JP6872169B2 - Exhaust gas treatment equipment and exhaust gas treatment method - Google Patents

Description

The present invention relates to a treatment device for exhaust gas containing mercury emitted from various factories such as a waste incinerator, a cement manufacturing factory, a thermal power plant, and a non-ferrous metal smelting factory, and an exhaust gas treatment method.

Exhaust gas emitted from cement kiln furnaces and non-ferrous metal smelting furnaces and waste containing mercury may be contained in the exhaust gas emitted by incinerators in waste incinerators, and are released to the atmosphere as they are. It causes air pollution and becomes a problem. Therefore, it is required to remove mercury in the exhaust gas.

Furthermore, the "Minamata Convention on Mercury" was adopted in 2013, and movements to strengthen mercury management worldwide are underway. After the entry into force of this treaty, measures to curb mercury emissions have been considered for facilities subject to mercury emission regulations. Facilities subject to mercury emission control include coal-fired power plants, coal-fired boilers, non-ferrous metal smelting facilities, waste incinerator facilities, and cement manufacturing facilities. Under such circumstances, there is an increasing demand for a treatment method for efficiently removing mercury in the exhaust gas emitted from these facilities.

For example, as a general method for removing mercury in exhaust gas discharged from a waste incinerator or a boiler furnace, a bug filter for removing dust in the exhaust gas, a duct for guiding the exhaust gas to an electrostatic precipitator, a bug filter, etc. On the other hand, there is known a method in which powdered and granular activated carbon is blown at an upstream position, mercury is adsorbed on the activated carbon, and the activated carbon adsorbing the mercury is collected together with dust by a bag filter or the like and removed from the exhaust gas.

Depending on the type of waste incinerated in the incinerator and the type of raw material smelted in the cement kiln furnace and non-ferrous metal smelting furnace, the mercury concentration in the exhaust gas may fluctuate to temporarily increase. There is. Even in this case, in order to keep the mercury concentration in the exhaust gas discharged from the chimney low, it is necessary to constantly blow a large amount of activated carbon to be blown into the duct.

In this way, if a large amount of activated carbon is constantly supplied into the duct assuming a temporarily high mercury concentration, the result is that the activated carbon is excessively supplied in many time zones other than the above-mentioned temporary time zone. This causes a problem that the amount of activated carbon used becomes large and the exhaust gas treatment cost increases, and a problem that the amount of dust collected becomes large and the dust removal treatment cost increases. Therefore, in Patent Document 1, the exhaust gas flow path for guiding the exhaust gas containing mercury discharged from the furnace is provided with a dust collecting device for removing the exhaust gas and an activated carbon supply device for blowing activated carbon into the exhaust gas flow path, and is provided on the downstream side of the furnace. It is equipped with an upstream mercury concentration meter that measures the mercury concentration in the exhaust gas on the upstream side of the dust collector and a control device that controls the amount of activated carbon supplied by the activated carbon supply device. An exhaust gas treatment device that controls the amount of activated carbon supplied so that the mercury concentration in the exhaust gas on the downstream side of the dust collector is set to a set value or less based on the concentration measurement value is disclosed. According to the exhaust gas treatment device of Patent Document 1, the mercury concentration is measured by a mercury concentration meter on the downstream side of the furnace and on the upstream side of the dust collector, and the activated carbon supply amount is adjusted based on the measured value to collect dust. The mercury concentration in the exhaust gas on the downstream side of the device shall be below the allowable set value. When the mercury concentration in the exhaust gas from the furnace fluctuates, the mercury concentration can be measured before the exhaust gas flows into the dust collector, and the activated carbon supply amount can be quickly adjusted to an appropriate amount based on the measured value. The mercury concentration in the exhaust gas discharged from the chimney can be surely kept below the allowable set value without delaying the fluctuation of the mercury concentration, and it is not necessary to constantly inject a large amount of activated carbon. Therefore, the amount of activated carbon used can be reduced and the operating cost can be reduced.

International release 2016/132894

When the exhaust gas treatment device of Patent Document 1 is to be applied to a facility having a plurality of exhaust gas flow paths corresponding to each of a plurality of furnaces, a mercury concentration meter is installed for each exhaust gas treatment device attached to each exhaust gas flow path. There is a need. The mercury concentration meter installed on the upstream side of the dust collector measures the exhaust gas containing dust, so it is equipped with a filter mechanism to filter the dust and introduce the exhaust gas into the mercury concentration measurement sensor at a high price. Therefore, since a plurality of such mercury concentration meters are provided, there arises a problem that the equipment cost of the exhaust gas treatment device increases.

In view of such circumstances, the present invention reliably adsorbs and removes mercury in the exhaust gas in a facility provided with a plurality of furnaces, and supplies activated carbon with an appropriate amount of activated carbon even if the mercury concentration in the exhaust gas fluctuates. At the same time, it is an object to provide an exhaust gas treatment device and an exhaust gas treatment method that suppress the rise in equipment cost.

According to the present invention, the above-mentioned problems are solved by the following exhaust gas treatment device and further exhaust gas treatment method.

[Exhaust gas treatment equipment]
The exhaust gas treatment device in the present invention is configured as the following first invention, second invention and third invention, and the above-mentioned problems are solved by any of them.

<First invention>
In order to treat the exhaust gas containing mercury discharged from multiple furnaces, in each exhaust gas flow path that guides the exhaust gas discharged from each furnace, a dust collector that removes the exhaust gas and an upstream side of the dust collector In an exhaust gas treatment device provided with an activated carbon supply device that blows activated carbon into each exhaust gas flow path.
A mercury concentration measuring device that measures the mercury concentration of the confluence of exhaust gas collected from the exhaust gas flow path at a position downstream of the furnace and upstream of the dust collector in each exhaust gas flow path, and activated carbon of multiple activated carbon supply devices. Equipped with a control device to control the supply amount
The control device controls the amount of activated carbon supplied so that the concentration of activated carbon in the exhaust gas on the downstream side of the dust collector is equal to or less than the set value based on the value measured by the mercury concentration measuring device. An exhaust gas treatment device characterized by.

<Second invention>
In order to treat the exhaust gas containing mercury discharged from multiple furnaces, in each exhaust gas flow path that guides the exhaust gas discharged from each furnace, a dust collector that removes the exhaust gas and an upstream side of the dust collector In an exhaust gas treatment device provided with an activated carbon supply device that blows activated carbon into each exhaust gas flow path.
An upstream mercury concentration meter that measures the mercury concentration of the confluence of exhaust gas collected from the exhaust gas flow path at the position downstream of the furnace and upstream side of the dust collector in each exhaust gas flow path, and in each exhaust gas flow path. The control device includes a mercury concentration measuring device having a downstream mercury concentration meter that measures the mercury concentration in the exhaust gas on the downstream side of the dust collector, and a control device that controls the amount of activated carbon supplied by a plurality of activated carbon supply devices. , The amount of activated carbon supplied is set to the set value or less in the exhaust gas on the downstream side of the dust collector based on the mercury concentration measurement value by the upstream mercury concentration meter and the mercury concentration measurement value by the downstream mercury concentration meter. An exhaust gas treatment device characterized by controlling the amount of activated carbon supplied.

<Third invention>
In order to treat the exhaust gas containing mercury discharged from multiple furnaces, in each exhaust gas flow path that guides the exhaust gas discharged from each furnace, a dust collector that removes the exhaust gas and an upstream side of the dust collector In an exhaust gas treatment device provided with an activated carbon supply device that blows activated carbon into each exhaust gas flow path.
An upstream mercury concentration meter that measures the mercury concentration of the confluence of exhaust gas collected from the exhaust gas flow path at the position downstream of the furnace and upstream side of the dust collector in each exhaust gas flow path, and in each exhaust gas flow path. It is equipped with a downstream mercury concentration meter that measures the mercury concentration in the exhaust gas on the downstream side of the dust collector and a control device that controls the amount of activated carbon supplied by multiple activated carbon supply devices. Based on the first control that controls the amount of activated carbon supplied based on the measured value of mercury concentration and the value measured by the downstream mercury concentration meter, the concentration of mercury in the exhaust gas on the downstream side of each dust collector is less than or equal to the set value. An exhaust gas treatment device characterized in that a second control for controlling the amount of activated carbon supplied is performed.

In the first to third inventions, it is preferable that the control device controls the amount of activated carbon supplied so as to maintain a predetermined minimum value or more. By maintaining a predetermined minimum value, an adsorption layer of activated carbon is always formed on the bag filter of the dust collector, so that even when exhaust gas containing a high concentration of mercury is discharged. By the adsorption removal action by the above-mentioned adsorption layer formed in advance and the adsorption removal action by the activated carbon blown at that time, mercury can be quickly and surely adsorbed and removed, and the mercury concentration of the exhaust gas after dust collection is sufficiently low. can do.

In the first to third inventions, it is preferable that the control device is controlled so that the amount of activated charcoal supplied is maintained at a predetermined maximum value when the mercury concentration measured value by the mercury concentration measuring device is equal to or higher than a predetermined mercury concentration. When the mercury concentration rises temporarily and suddenly even though the mercury concentration is not so high as an hourly average, if a large amount of activated carbon is supplied in accordance with this high mercury concentration, the activated carbon will be excessively generated over the subsequent time. The result is that it will be supplied. Such an excessive supply can be prevented by controlling the amount of the activated carbon supply to be maintained at a predetermined maximum value.

Further, in the first to third inventions, regarding the increase from the minimum value to the maximum value of the activated coal supply amount, the control device starts from the value where the measured mercury concentration in the exhaust gas is zero or less than the measurable limit minimum value. In the range until the first predetermined mercury concentration is reached, the activated charcoal is supplied under the predetermined minimum value of the activated charcoal supply amount, and after the mercury concentration measurement value reaches the first predetermined mercury concentration, the mercury The amount of activated charcoal supplied is linearly increased from a predetermined minimum value as the measured concentration value increases, and when the measured mercury concentration reaches the second predetermined mercury concentration, the amount of activated charcoal supplied is supplied at a predetermined maximum value. After the mercury concentration measurement value reaches the second predetermined mercury concentration, the amount of activated charcoal can be kept constant at the predetermined maximum value with respect to the increase in the mercury concentration measurement value.

Further, in the first to third inventions, regarding the increase from the minimum value to the maximum value of the activated carbon supply amount, the control device starts from the value where the measured value of the mercury concentration in the exhaust gas is zero or less than the measurable limit minimum value. In the range until the first predetermined mercury concentration is reached, the activated carbon is supplied under the activated carbon supply amount which is the first supply amount at the predetermined minimum value, and the measured mercury concentration is the above-mentioned first predetermined mercury. When the concentration is reached, the amount of activated carbon supplied is stepwise increased to a predetermined second supply amount, and the amount of activated carbon supplied is increased to the range until the measured mercury concentration reaches the second predetermined mercury concentration. Keep constant at the second supply amount, and increase the activated carbon supply amount to the predetermined third supply amount when the mercury concentration measurement value reaches the second predetermined mercury concentration. The amount of activated carbon supplied is repeatedly increased in a stepwise manner as the amount of activated carbon is increased, and after the amount of activated carbon supplied is increased to a predetermined maximum value, the activated carbon is activated at the predetermined maximum value with respect to the increase in the measured mercury concentration value. It is also possible to keep the supply constant.

As described above, by increasing the amount of activated carbon supplied from the minimum value to the maximum value based on the measured value of mercury concentration in the exhaust gas, the activated carbon supply does not cause any trouble in the supply amount adjustment mechanism of the activated carbon supply device. The amount can be controlled smoothly.

[Exhaust gas treatment method]
The exhaust gas treatment method in the present invention is configured as the following fourth invention, fifth invention and sixth invention, and the above-mentioned problems are solved by any of them.

<Fourth invention>
In order to treat the exhaust gas containing mercury discharged from a plurality of furnaces, the exhaust gas is dust-removed by a dust collector in each exhaust gas flow path that guides the exhaust gas discharged from each furnace, and each is discharged on the upstream side of the dust collector. In the exhaust gas treatment method in which activated carbon is blown into the exhaust gas flow path from the activated carbon supply device,
The mercury concentration of the confluence of exhaust gas collected from multiple exhaust gas channels is measured by a mercury concentration measuring device at the position downstream of the furnace and upstream of the dust collector in each exhaust gas channel, and multiple activated carbon supply devices. It was decided that the amount of activated carbon supplied would be controlled by a control device.
The control device controls the amount of activated carbon supplied so that the concentration of activated carbon in the exhaust gas on the downstream side of the dust collector is equal to or less than the set value based on the value measured by the mercury concentration measuring device. An exhaust gas treatment method characterized by.

<Fifth invention>
In order to treat the exhaust gas containing mercury discharged from a plurality of furnaces, the exhaust gas is dust-removed by a dust collector in each exhaust gas flow path that guides the exhaust gas discharged from each furnace, and each is discharged on the upstream side of the dust collector. In the exhaust gas treatment method in which activated carbon is blown into the exhaust gas flow path from the activated carbon supply device,
An upstream mercury concentration meter that measures the mercury concentration of the confluence of exhaust gas collected from multiple exhaust gas channels at a position downstream of the furnace and upstream of the dust collector in each exhaust gas flow path, and each exhaust gas flow. The mercury concentration is measured by a mercury concentration measuring device having a downstream mercury concentration meter that measures the mercury concentration in the exhaust gas on the downstream side of the dust collector on the road.
It was decided to control the amount of activated carbon supplied by multiple activated carbon supply devices.
With the control device, the amount of activated carbon supplied is set based on the mercury concentration measurement value by the upstream mercury concentration meter and the mercury concentration measurement value by the downstream mercury concentration meter, and the mercury concentration in the exhaust gas on the downstream side of the dust collector is set. An exhaust gas treatment method characterized by controlling the amount of activated carbon supplied as follows.

<Sixth invention>
In order to treat the exhaust gas containing mercury discharged from a plurality of furnaces, the exhaust gas is dust-removed by a dust collector in each exhaust gas flow path that guides the exhaust gas discharged from each furnace, and each is discharged on the upstream side of the dust collector. In the exhaust gas treatment method in which activated carbon is blown into the exhaust gas flow path from the activated carbon supply device,
An upstream mercury concentration meter that measures the mercury concentration of the confluence of exhaust gas collected from multiple exhaust gas channels at a position downstream of the furnace and upstream of the dust collector in each exhaust gas flow path, and each exhaust gas flow. The mercury concentration is measured by a mercury concentration measuring device having a downstream mercury concentration meter that measures the mercury concentration in the exhaust gas on the downstream side of the dust collector on the road.
It was decided to control the amount of activated carbon supplied by multiple activated carbon supply devices.
The control device controls the amount of activated coal supplied based on the mercury concentration measured by the upstream mercury concentration meter, and in the exhaust gas on the downstream side of each dust collector based on the mercury concentration measured by the downstream mercury concentration meter. An exhaust gas treatment method characterized in that the amount of activated carbon supplied is controlled so that the mercury concentration is equal to or less than a set value.

In the fourth to sixth inventions, it is preferable that the control step is controlled so as to maintain the amount of activated carbon supplied to a predetermined minimum value or more. By maintaining a predetermined minimum value, an adsorption layer of activated carbon is always formed on the bag filter of the dust collector, so that exhaust gas containing a high concentration of mercury is discharged. In this case, mercury can be quickly and surely adsorbed and removed by the adsorption removal action by the above-mentioned adsorption layer formed in advance and the adsorption removal action by the activated carbon blown at that time, and the mercury concentration of the exhaust gas after dust collection can be sufficiently reduced. It can be low concentration.

In the fourth to sixth inventions, it is preferable that the control step is controlled so that the amount of activated charcoal supplied is maintained at a predetermined maximum value when the mercury concentration measured value by the mercury concentration measuring device is equal to or higher than a predetermined mercury concentration. When the mercury concentration rises temporarily and suddenly even though the mercury concentration is not so high as an hourly average, if a large amount of activated carbon is supplied in accordance with this high mercury concentration, the activated carbon will be excessively generated over the subsequent time. The result is that it will be supplied. Such an excessive supply can be prevented by controlling the amount of the activated carbon supply to be maintained at a predetermined maximum value.

Further, in the fourth to sixth inventions, regarding the increase from the minimum value to the maximum value of the activated coal supply amount, the control step starts from the value where the measured mercury concentration in the exhaust gas is zero or less than the measurable limit minimum value. In the range until the first predetermined mercury concentration is reached, the activated charcoal is supplied under the predetermined minimum value of the activated charcoal supply amount, and after the mercury concentration measurement value reaches the first predetermined mercury concentration, the mercury The amount of activated charcoal supplied is linearly increased from a predetermined minimum value as the measured concentration value increases, and when the measured mercury concentration reaches the second predetermined mercury concentration, the amount of activated charcoal supplied is supplied at a predetermined maximum value. After the mercury concentration measurement value reaches the second predetermined mercury concentration, the amount of activated charcoal can be kept constant at the predetermined maximum value with respect to the increase in the mercury concentration measurement value.

Further, in the fourth to sixth inventions, regarding the increase from the minimum value to the maximum value of the activated coal supply amount, the control step starts from the value where the measured mercury concentration of the exhaust gas is zero or less than the measurable limit minimum value. In the range until the first predetermined mercury concentration is reached, the activated charcoal is supplied under the activated charcoal supply amount which is the first supply amount at the predetermined minimum value, and the measured mercury concentration is the first predetermined mercury concentration. When the amount reaches, the amount of activated charcoal supply is increased stepwise to a predetermined second supply amount, and the amount of activated charcoal supply is increased to the range until the measured mercury concentration reaches the second predetermined mercury concentration. In addition, when the mercury concentration measurement value reaches the second predetermined mercury concentration, the activated charcoal supply amount is increased to the predetermined third supply amount. The amount of activated charcoal supplied is repeatedly increased in a stepwise manner as the amount increases, and after the amount of activated charcoal supply is increased to a predetermined maximum value, the activated charcoal is supplied at the predetermined maximum value with respect to the increase in the measured mercury concentration. You can also try to keep the amount constant.

As described above, by increasing the activated carbon supply amount from the minimum value to the maximum value based on the measured value of the mercury concentration of the exhaust gas, the activated carbon supply amount does not cause a problem for the supply amount adjustment mechanism of the activated carbon supply device. Can be controlled smoothly.

According to the present invention as described above, in the first invention and the fourth invention, the mercury concentration is measured by a mercury concentration meter on the downstream side of the furnace and on the upstream side of the dust collector, and the activated charcoal is supplied based on the measured value. Adjust the amount so that the mercury concentration in the exhaust gas on the downstream side of the dust collector is below the allowable set value. When the mercury concentration in the exhaust gas from the furnace fluctuates, the mercury concentration can be measured before the exhaust gas flows into the dust collector, and the amount of activated charcoal supplied can be quickly adjusted to an appropriate amount based on the measured value. The mercury concentration in the exhaust gas discharged from the chimney can be surely set to an allowable set value or less without delaying the fluctuation of the mercury concentration.

Moreover, in the first invention and the fourth invention, the exhaust gas from each of the plurality of exhaust gas channels is collected and used as a confluence to measure the mercury concentration of the confluence, so that even if there are a plurality of exhaust gas channels. Only one mercury concentration measuring device is required. The measured mercury concentration of the confluence is the average value of the mercury concentration of the exhaust gas in multiple exhaust gas channels, but the activated carbon supply amount should be set higher than the activated carbon supply amount commensurate with this average value. For example, it can sufficiently handle any exhaust gas flow path. Since the mercury concentration measuring device is equipped with a filter for removing dust so that the mercury concentration of the exhaust gas including dust can be measured and is expensive, as described above, even if there are a plurality of exhaust gas channels, only one mercury concentration measuring device is required. This means that the equipment cost is reduced and it is economically advantageous as compared with the case where each exhaust gas flow path is provided with a mercury concentration measuring device.

In the second invention, the third invention, the fifth invention and the sixth invention, the mercury concentration of the confluence of the exhaust gas collected on the downstream side of the furnace on the downstream side of the dust collector and on the upstream side of the dust collector for each of the plurality of exhaust gas channels is increased upstream. In addition to measuring with the side mercury concentration meter, measure the mercury concentration individually for each exhaust gas flow path on the downstream side of the dust collector with the downstream mercury concentration meter, and adjust the amount of activated charcoal supply based on these two measured values. Set the mercury concentration on the downstream side of the dust collector to the set value or less. In this way, the first control that determines the base value of the amount of activated carbon supplied is performed based on the measured mercury concentration of the confluence of exhaust gas collected on the downstream side of the furnace on the downstream side of the exhaust gas flow path and on the upstream side of the dust collector. The amount of activated carbon supplied is adjusted promptly, and the amount of activated carbon supplied to each exhaust gas flow path is individually increased or decreased from the above base value based on the measured value of mercury concentration on the downstream side of the dust collector. Is complemented to perform the second control. By doing so, it is possible to more reliably reduce the mercury concentration in the exhaust gas discharged from the chimney to the set value or less without causing a delay with respect to the fluctuation of the mercury concentration. Since activated carbon is individually supplied to each exhaust gas flow path based on the measurement of the mercury concentration on the downstream side of the dust collector so as to complement the amount of activated carbon supplied, control based on the measurement of the mercury concentration of the confluent is performed. Further, in the fourth invention, the amount of activated carbon supplied to the exhaust gas flow path having a low mercury concentration can be suppressed to be lower than that set to a higher amount.

As described above, according to the present invention, the mercury concentration in the exhaust gas in the exhaust gas flow path provided in each of the plurality of furnaces is measured on the upstream side of the dust collector, or on the upstream side and the downstream side of the dust collector. Then, since the amount of activated carbon to be blown in is adjusted based on the measured value of the mercury concentration, the concentration of mercury in the exhaust gas discharged from the chimney is surely below the predetermined value, and the activated carbon is supplied in just proportion. The amount used can be reduced and the exhaust gas treatment cost can be reduced. Moreover, in the present invention, the mercury concentration on the upstream side of the dust collector is measured by one mercury concentration measuring device for the confluence of exhaust gas collected from a plurality of exhaust gas channels. Compared with the case where the mercury concentration measuring device is provided on the road, the equipment cost is reduced, which is economically advantageous.

It is a schematic block diagram of the 1st Embodiment apparatus of this invention. It is a schematic block diagram of the 2nd Embodiment apparatus of this invention. (A) to (H) show various patterns that can be adopted as the relationship between the mercury concentration in the exhaust gas and the amount of activated carbon supplied. It is a figure which shows the relationship between the mercury concentration at the inlet of a bag filter, and the amount of activated carbon supply used in the comparative example of this invention. It is a figure which shows the relationship between the exhaust gas confluent mercury concentration and activated carbon supply amount used in the Example of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In the present embodiment shown below, an incinerator that incinerates waste is described as a furnace that emits exhaust gas containing mercury, but the present invention is not limited to this, and the present invention is not limited to this, and a cement kiln furnace and non-ferrous metal smelting are described. It can be used as a treatment device and a treatment method for exhaust gas containing mercury discharged from various furnaces such as a furnace.

For the exhaust gas from the incinerator that incinerates waste, activated carbon is blown into the exhaust gas flow path at the upstream position of the bug filter installed for dust collection, so that the mercury concentration on the downstream side of the bug filter is extremely low. Although it is possible to control the level, conventionally, when the mercury concentration in the exhaust gas from the incinerator fluctuates due to fluctuations in the type and amount of waste, the mercury concentration temporarily rises on the downstream side of the bag filter. In preparation for this, it is necessary to inject a large amount of activated carbon at all times, which increases the cost of exhaust gas treatment. Therefore, in the present embodiment, the mercury concentration is measured by a mercury concentration meter, and the amount of activated carbon in excess or deficiency is blown into the exhaust gas flow path based on the measured mercury concentration. The mercury densitometer is preferably in the form of continuous measurement.

<First Embodiment>
In FIG. 1 showing an outline configuration of the apparatus of the present embodiment, two exhaust gas flow paths A; B are provided to guide the exhaust gas discharged from each of the two incinerators 1A; 1B to the chimney 4A; 4B by a separate route. There is. In the present embodiment, an example in which two exhaust gas flow paths A; B are provided corresponding to two incinerators 1A; 1B is shown, but the present invention is not limited to this, and three or more are provided. Three or more exhaust gas channels may be provided corresponding to the incinerator. In FIG. 1, various devices provided corresponding to the two exhaust gas flow paths A; B are respectively assigned a numerical code A; B, and are common to both exhaust gas flow paths A; B. Only the numerical code shall be attached to the various devices provided in the above.

Each of the above two exhaust gas flow paths A; B has an incinerator 1A; 1B, a boiler 2A; 2B, and a bug filter 3A; 3B as a dust collector from the upstream side (left side in the figure) to the downstream side. And the chimneys 4A; 4B are provided. An activated carbon supply device 5A; 5B is provided on the side of the pipeline between the boiler 2A; 2B of the exhaust gas flow path A; B and the bag filter 3A; 3B, and is on the upstream side of the bag filter 3A; 3B. It is connected to the.

In FIG. 1, in two exhaust gas flow paths A; B, a sampling pipe 6A; 6B for collecting exhaust gas for measuring the mercury concentration in the exhaust gas is connected between the boiler 2A; 2B and the bag filter 3A; 3B. The two sampling pipes 6A; 6B are connected so as to merge, and the exhaust gas from both the sampled exhaust gas flow paths A; B form a confluence. The detection unit 7-1 of the mercury concentration measuring device 7 is arranged connected to the confluence position of both sampling tubes 6A; 6B. The mercury concentration measuring device 7 is connected to the control device 8 so as to measure the mercury concentration of the confluence of exhaust gas and send the mercury concentration measurement value of the confluence to the control device 8, and the control device 8 supplies the activated carbon. It is connected to the device 5A; 5B and issues an activated carbon supply command signal to both activated carbon supply devices 5A; 5B. The control device 8 sets the mercury concentration at a position downstream of the bag filter 3A; 3B to a predetermined predetermined mercury concentration value or less based on the mercury concentration measurement value of the exhaust gas confluence received from the mercury concentration measuring device 7. In addition, the activated carbon supply device 5A; 5B is controlled.

In the present embodiment, as seen in FIG. 1, the activated carbon by the activated carbon supply device 5A; 5B, which is on the downstream side of the incinerator 1A; 1B in the exhaust gas flow path A; B and on the upstream side of the bag filter 3A; 3B. A sampling pipe 6A; 6B for collecting exhaust gas from a position upstream of the blowing position is connected, and the mercury concentration measuring device 7 measures the mercury concentration of the exhaust gas confluent at the confluence position of the sampling pipe 6A; 6B. It is arranged so as to. In the present embodiment, the control device 8 grasps the relationship between the mercury concentration and the amount of activated carbon supplied from the exhaust gas confluence and the mercury concentration at a position downstream of the bag filters 3A; 3B based on the accumulated data. Therefore, the mercury concentration of the confluence of exhaust gas collected at a position upstream of the activated carbon injection position is measured, and the mercury concentration downstream of the bag filter 3A; 3B is estimated from the measured mercury concentration and the amount of activated carbon supplied. it can. That is, the mercury concentration downstream of the bag filter 3A; 3B is estimated based on the measured mercury concentration of the confluence of exhaust gas collected at a position upstream of the activated carbon blowing position by the control device 8, and the estimated mercury is estimated. The amount of activated carbon supplied to keep the concentration below a predetermined mercury concentration value can be obtained, and the amount of activated carbon supplied by the activated carbon supply device 3 is controlled. As a result, the mercury concentration downstream of the bug filters 3A; 3B is set to be equal to or less than the predetermined mercury concentration value.

Although not shown, the activated carbon supply devices 5A; 5B are specifically provided, for example, with a hopper for accommodating activated carbon, a rotary type cutting member provided at the lower outlet of the hopper, and further below the hopper. It has a valve or a damper. In the activated carbon supply device 5A; 5B, at least one of the rotation speed of the rotary of the cutting member, the opening degree of the valve, and the opening degree of the damper is adjusted in response to the command signal from the control device 8, and the activated carbon is adjusted. It is supplied to the exhaust gas flow paths A; B under the amount.

In this embodiment, when the mercury concentration in the exhaust gas from the incinerator 1A; 1B fluctuates, it is on the downstream side of the incinerator 1A; 1B and on the upstream side of the activated carbon blowing position by the activated carbon supply device 5A; 5B. Since the mercury concentration measuring device 7 measures the mercury concentration of the confluence of the exhaust gas collected at the position and detects the fluctuation of the mercury concentration, it is possible to quickly adjust the amount of activated carbon supplied, so there is no time lag and the chimney. The mercury concentration in the exhaust gas inside can be reliably maintained below the set value.

In such an embodiment, when the mercury concentration in the exhaust gas is different between the exhaust gas from the incinerator 1A in the exhaust gas flow path A and the exhaust gas from the incinerator 1B in the exhaust gas flow path B, both exhaust gas flow paths A; In a state where a part of the exhaust gas is collected from B by the sampling pipe 6A; 6B and merged to form a merged product, the mercury concentration of the merged product detected by the detection unit 7-1 is measured by the mercury concentration measuring device 7. .. The measured mercury concentration is the average value of the mercury concentration of the exhaust gas in both the exhaust gas channels A and B. In the present embodiment, in the control device 8, an activated carbon supply amount higher than the activated carbon supply amount required for the mercury concentration corresponding to this average value is set. That is, the variation in the mercury concentration of the exhaust gas in each exhaust gas flow path A; B is set to an appropriate amount of activated carbon supply with respect to the higher mercury concentration predicted from those results. Therefore, from the activated carbon supply device 5A; 5B, the activated carbon is supplied in a slightly excessive amount to one of the exhaust gas channels A or B having a mercury concentration lower than the above average value.

Thus, the mercury is removed by the bag filter 3A; 3B while being adsorbed by the activated carbon, and the exhaust gas is discharged from the chimney 4A; 4B into the atmosphere in a detoxified state.

<Second embodiment>
Compared to the first embodiment described above, the present embodiment shown in FIG. 2 is characterized in that the mercury concentration measuring device consists of a first mercury concentration meter and a second mercury concentration meter that measure at different positions. is there. That is, the present embodiment corresponds to the mercury concentration measuring device of the first embodiment for measuring the mercury concentration of the confluence of exhaust gas collected from a position upstream of the activated carbon blowing position by the activated carbon supply device 5A; 5B. In addition to the first mercury concentration meter 7, the second mercury concentration meter 9A; 9B that measures the mercury concentration in the exhaust gas at the outlet of the bag filter 3A; 3B or the chimney 4A; 4B on the downstream side of the bag filter 3A; 3B is also available. It is provided. The first mercury concentration meter 7 is provided only for the confluence of the exhaust gas collected from the two exhaust gas channels A; B and merged, while the second mercury concentration meter has two exhaust gas flows. It is provided for each of the roads A and B. The measured values of the second mercury concentration meters 9A; 9B are sent to the control device 8 as an output signal. The present embodiment is the same as the first embodiment except for the point relating to the second mercury concentration meter. Therefore, in FIG. 2, the same reference numerals are given to the parts common to the parts in the first embodiment of FIG. 1, and the description thereof will be omitted.

In this embodiment, as seen in FIG. 2, the mercury concentration of the confluence of exhaust gas collected from a position upstream of the activated carbon blowing position by the activated carbon supply device 5A; 5B in the first embodiment described above. In addition to the first mercury concentration meter 7 for measuring, a second mercury concentration meter 9A is provided at the outlet of the bag filter 3A in one exhaust gas flow path A, and another at the outlet of the bag filter 3B in the other exhaust gas flow path B. One second mercury concentration meter 9B is provided. Similar to the first embodiment, based on the measured value by the first mercury concentration meter 7 for measuring the mercury concentration of the confluence of the exhaust gas collected from the position upstream of the activated carbon blowing position by the activated carbon supply device 5A; 5B. Therefore, as the first control, in addition to controlling the base value of the amount of activated carbon supplied, in the present embodiment, the first control is based on the value measured by the secondary mercury concentration meter 9A; 9B at the outlet of the bag filter 3A; 3B. (1) The activated carbon supply amount is controlled to be increased or decreased as the second control so as to complement the first control based on the measured value by the mercury concentration meter 7. Since the second mercury concentration meters 9A; 9B are provided exclusively for the two exhaust gas flow paths A; B, the control device 8 sends a separate command signal to the two activated carbon supply devices 5A; 5B. Activated carbon is supplied from each of the activated carbon supply devices 5A; 5B to the exhaust gas flow paths A; B in an appropriate complementary amount.

In the first embodiment, the mercury concentration of a part of the confluence of the exhaust gas collected from both the exhaust gas channels A and B is measured, and the measured mercury concentration is the mercury of the exhaust gas in both the exhaust gas channels A and B. It is an average value of the concentration, and the control device 8 sets an activated carbon supply amount higher than the required activated carbon supply amount for the mercury concentration corresponding to this average value, from the activated carbon supply device 5A; 5B. Will supply activated carbon in a slightly excessive amount to one of the exhaust gas channels A or B having a mercury concentration lower than the above average value. In the second embodiment, based on the measured values by the second mercury concentration meter 9A; 9B at the outlet of the bag filter 3A; 3B, the first control based on the measured values by the first mercury concentration meter 7 is complemented. As the second control, the activated carbon supply amount of the activated carbon supply device 5A; 5B is controlled to be increased or decreased separately, so that the activated carbon is supplied from each of the activated carbon supply devices 5A; 5B to the exhaust gas flow path A; B in an appropriate complementary amount. Therefore, the amount of activated carbon used can be adjusted without supplying an excessive amount of activated carbon.

The second mercury concentration meter 9A; 9B shows an example in which the respective detection units 9A-1 and 9B-1 are directly arranged in the exhaust gas flow path A; B in FIG. 2, but the present invention is not limited to this. Exhaust gas flow paths A; B may be provided with sampling pipes similar to those in the case of the first mercury concentration meter 7, and detection units 9A-1 and 9B-1 may be arranged in each sampling pipe, respectively.

In the present embodiment, the mercury concentration measurement value by the first mercury concentration meter 7 for measuring the mercury concentration of the confluence of the exhaust gas collected from the position upstream of the activation charcoal injection position by the activated charcoal supply device 5A; 5B is short. There is a time lag between the detection of the increasing phenomenon (called the mercury concentration measurement value peak) and the detection of the mercury concentration measurement value peak by the second mercury concentration meter 9A; 9B at the outlet of the bag filter 3A; 3B. Therefore, even when the mercury concentration measured value peak on the upstream side of the activated charcoal blowing position by the activated charcoal supply device 3 is no longer detected, the mercury concentration measured value peak may be detected at the outlet of the bag filter 3A; 3B. Therefore, by installing a second mercury concentration meter 9A; 9B and controlling the amount of activated charcoal supply based on the mercury concentration measurement value at the outlet of the bag filter 3A; 3B, the control based on the measurement value of the first mercury concentration meter 7 is complemented. Therefore, the mercury concentration in the exhaust gas in the chimney can be more reliably lowered to the set value or less.

In the embodiment of the present invention, the control device may control the activated carbon supply amount based on a predetermined correspondence between the mercury concentration measurement value by the mercury concentration meter and the activated carbon supply amount. Various forms can be applied as the correspondence between the predetermined mercury concentration measurement value and the amount of activated carbon supplied.

As for the correspondence between the predetermined mercury concentration measurement value and the activated carbon supply amount, the activated carbon supply amount is gradually increased starting from a predetermined minimum value as the mercury concentration in the exhaust gas measured by the mercury concentration measuring device increases. It may be in the form of a correspondence relationship with the maximum value. As a predetermined minimum value of the amount of activated carbon supplied, even if the concentration of mercury in the exhaust gas is extremely low during operation when the exhaust gas is discharged from the incinerator 1, the activated carbon is always blown at the minimum supply amount. By doing so, the value of the amount of activated carbon supplied that ensures that the concentration of mercury in the exhaust gas in the chimney can be maintained below the set value is determined. As the measured value of mercury concentration in exhaust gas increases, the amount of activated carbon supplied is gradually increased from a predetermined minimum value, and an appropriate amount of activated carbon is supplied with respect to the concentration of mercury in exhaust gas. In the form of the correspondence in which the amount of activated carbon supply is gradually increased from a predetermined minimum value, the amount of activated carbon supply may be increased linearly as the mercury concentration increases, or the amount of activated carbon supply may be increased stepwise in a plurality of steps. However, various forms of correspondence can be adopted. As a means for adjusting the amount of activated carbon supplied, in the case of the rotary valve type of the activated carbon supply device, it is necessary to adjust the rotation speed of the rotary of the cutting member, the opening degree of the valve, the opening degree of the damper, etc. individually or in combination. However, it is preferable to adopt a form of correspondence suitable for the adjustment range of these adjustment mechanisms and the characteristics of adjustment (for example, the supply amount can be continuously increased or decreased, or can be gradually increased or decreased).

FIG. 3 shows examples of various forms of the correspondence between the measured mercury concentration and the amount of activated carbon supplied.

In the form shown in FIG. 3 (A), the measured value of the mercury concentration in the exhaust gas is zero or less than the measurable limit minimum value, and the activated carbon supply amount having a predetermined minimum value is in the range from a predetermined mercury concentration to a predetermined value. When the measured value of the mercury concentration reaches the above-mentioned predetermined mercury concentration, the amount of activated carbon supplied is increased stepwise to the predetermined maximum value, and the mercury concentration in the exhaust gas is further increased. On the other hand, it is a form in which the amount of activated carbon supplied is kept constant at the predetermined maximum value. When the measured value of the mercury concentration is lower than the predetermined mercury concentration, the activated carbon supply amount is set to the predetermined minimum value, and when the mercury concentration is higher than the predetermined mercury concentration, the activated carbon supply amount is set to the predetermined maximum value. The amount of activated carbon supplied can be controlled by a flexible control mechanism.

In the form shown in FIG. 3B, the measured value of the mercury concentration in the exhaust gas is zero or less than the measurable limit minimum value, and the range from reaching the first predetermined mercury concentration is a predetermined minimum value. Activated charcoal is supplied based on the activated charcoal supply amount (first supply amount), and when the measured value of the mercury concentration reaches the above-mentioned first predetermined mercury concentration, the activated charcoal supply amount is set in a stepwise manner to the predetermined second predetermined mercury concentration. When the supply amount is increased, the activated charcoal supply amount is kept constant at the second supply amount in response to the increase in the mercury concentration in the exhaust gas, and the measured value of the mercury concentration reaches the second predetermined mercury concentration. In order to increase the amount of activated charcoal supply to a predetermined third supply amount, the amount of activated charcoal supply is repeatedly increased in a fine stepwise manner as the mercury concentration in the exhaust gas increases, and the amount of activated charcoal supply is increased to a predetermined maximum value. After increasing to, the amount of activated coal supplied is kept constant at a predetermined maximum value against an increase in the mercury concentration in the exhaust gas. By increasing the amount of activated carbon supplied stepwise from a predetermined minimum value to a predetermined maximum value as the mercury concentration in the exhaust gas increases, the supply of activated carbon is supplied in a more appropriate amount with respect to the mercury concentration in the exhaust gas. Can be controlled as

The form shown in FIG. 3C is a form in which the amount of activated carbon supplied is linearly increased from a predetermined minimum value as the mercury concentration in the exhaust gas increases. Further, in the form shown in FIG. 3D, activated carbon is linearly supplied from a predetermined minimum value as the mercury concentration in the exhaust gas increases within the range until the measured value of the mercury concentration in the exhaust gas reaches the predetermined mercury concentration. The amount was increased, and when the measured value of the mercury concentration reached the mercury concentration in the predetermined exhaust gas, the activated carbon supply amount was set to the predetermined maximum value, and the activated carbon supply amount was increased to the predetermined maximum value. After that, the amount of activated carbon supplied is kept constant at a predetermined maximum value against an increase in the concentration of mercury in the exhaust gas. In the modes shown in FIGS. 3C and 3D, the amount of activated carbon supplied is continuously increased from a predetermined minimum value as the mercury concentration in the exhaust gas increases, so that the amount is finely adjusted with respect to the mercury concentration in the exhaust gas. Can be controlled to supply activated carbon at.

In the form shown in FIG. 3 (E), the range from the measured value of the mercury concentration in the exhaust gas to zero or less than the measurable limit minimum value to reaching the first predetermined mercury concentration is a predetermined minimum value. Activated carbon is supplied based on the amount of activated carbon supplied, and after the measured value of the mercury concentration reaches the above-mentioned first predetermined mercury concentration, the amount of activated carbon supplied linearly from the predetermined minimum value as the mercury concentration in the exhaust gas increases. When the measured value of the mercury concentration reaches the second predetermined mercury concentration, the activated carbon supply amount is set to the predetermined maximum value, and after the activated carbon supply amount is increased to the predetermined maximum value, , It is a form in which the amount of activated carbon supplied is kept constant at a predetermined maximum value against an increase in the concentration of mercury in the exhaust gas. The form shown in FIG. 3 (E) is a combination of the forms shown in FIGS. 3 (A) and 3 (C), and has the characteristics and effects of each form.

In the form shown in FIG. 3 (F), the range from the measured value of the mercury concentration in the exhaust gas to zero or less than the measurable limit minimum value to reaching the first predetermined mercury concentration is a predetermined minimum value. Activated charcoal is supplied based on the amount of activated charcoal supplied (first supply amount), and after the measured value of mercury concentration reaches the above-mentioned first predetermined mercury concentration, the first supply is made as the mercury concentration in the exhaust gas increases. The amount of activated charcoal supply is linearly increased from the amount, and the amount is increased to the second supply amount corresponding to the second predetermined mercury concentration, and then the activated charcoal supply amount is increased to the second supply amount in response to the increase in mercury concentration in the exhaust gas. When the third predetermined mercury concentration is reached, the activated coal supply amount is linearly increased from the second supply amount to reach the third supply amount corresponding to the fourth predetermined mercury concentration. After that, the amount of activated charcoal supplied was kept constant at the third supply amount in response to the increase in mercury concentration in exhaust gas, and the amount of activated charcoal supplied was kept constant and increased in response to such an increase in mercury concentration in exhaust gas. After repeatedly increasing the amount of activated charcoal supply to a predetermined maximum value, the activated charcoal supply amount is kept constant at the predetermined maximum value with respect to the increase in the mercury concentration in the exhaust gas. The form shown in FIG. 3 (F) is a combination of the forms shown in FIGS. 3 (B) and 3 (D), and has the characteristics and effects of each form.

In the form shown in FIG. 3 (G), the amount of activated carbon supplied is linearly increased from a predetermined minimum value as the mercury concentration in the exhaust gas increases until the measured value of the mercury concentration in the exhaust gas reaches the predetermined mercury concentration. When the measured value of the mercury concentration reaches the above-mentioned predetermined mercury concentration, the activated carbon supply amount is increased to the predetermined maximum value in a stepwise manner, and after the activated carbon supply amount is increased to the predetermined maximum value, the exhaust gas is exhausted. It is a form in which the amount of activated carbon supplied is kept constant at a predetermined maximum value with respect to an increase in the concentration of medium mercury. When the measured value of the mercury concentration in the exhaust gas is lower than the predetermined value, which is relatively medium, the amount of activated carbon supplied in the exhaust gas is continuously increased from the predetermined minimum value as the mercury concentration in the exhaust gas increases. It is possible to finely control the supply of activated carbon in an appropriate amount with respect to the mercury concentration, and when the measured value of the mercury concentration in the exhaust gas is higher than the predetermined mercury concentration, which is relatively medium, the amount of activated carbon supplied is set to the specified maximum. It is a correspondence relationship to be set as a value, and the activated carbon supply amount can be controlled by an appropriate amount by effectively utilizing a plurality of means for adjusting the activated carbon supply amount.

In the form shown in FIG. 3H, the amount of activated charcoal supplied linearly from a predetermined minimum value as the mercury concentration in the exhaust gas increases until the measured value of the mercury concentration in the exhaust gas reaches the first predetermined mercury concentration. When the measured value of the mercury concentration reaches the first predetermined mercury concentration, the activated charcoal supply amount is set as the predetermined first supply amount, and the measured value of the mercury concentration reaches the second predetermined mercury concentration. Until then, the amount of activated charcoal supply is kept constant at a predetermined first supply amount, and when the measured value of mercury concentration reaches the above-mentioned second predetermined mercury concentration, the amount of activated charcoal supply is stepped up to a predetermined maximum value. After increasing the amount of activated charcoal supply to a predetermined maximum value, the amount of activated charcoal supply is kept constant at the predetermined maximum value with respect to the increase in the mercury concentration in the exhaust gas. The form shown in FIG. 3 (H) has a predetermined range in which the measured value of the mercury concentration in the exhaust gas is relatively medium (from the first predetermined mercury concentration to the second predetermined silver concentration) in the form shown in FIG. 3 (G). In the range up to), it is a form in which the amount of activated carbon supplied is kept constant at the first predetermined supply amount, and the supply of activated carbon can be controlled to be supplied in a more appropriate amount.

Further, when the control device controls the activated coal supply amount based on the correspondence relationship between the mercury concentration measured value by the mercury concentration meter and the activated charcoal supply amount, the correspondence relationship between the predetermined mercury concentration measured value and the activated charcoal supply amount is determined. As a form, when the measured mercury concentration in the exhaust gas is zero or less than the measurable limit minimum value of the mercury concentration meter or lower than the predetermined value set in advance, the activated charcoal is not supplied and the mercury concentration in the exhaust gas is zero or measurable. When the limit is higher than the minimum value or a predetermined value set in advance, the amount of activated charcoal supplied may be gradually increased as the concentration of mercury in the exhaust gas increases. Further, when the amount of activated carbon supplied is increased according to the increase in the mercury concentration in the exhaust gas, it may be increased linearly or stepwise.

In addition, as another form of the above correspondence, when the measured mercury concentration in the exhaust gas is zero or less than the measurable limit minimum value of the mercury concentration meter or lower than the predetermined first predetermined mercury concentration, the activated charcoal is supplied. As the mercury concentration in the exhaust gas increases, the mercury concentration in the exhaust gas is zero, the minimum measurable value, or higher than the predetermined first predetermined mercury concentration and lower than the predetermined second predetermined mercury concentration. , The amount of activated charcoal supplied may be gradually increased, and the amount of activated charcoal supplied may be kept constant as a predetermined amount within a range in which the measured value of the mercury concentration in the exhaust gas is higher than the above-mentioned second predetermined mercury concentration. Further, when the amount of activated carbon supplied is increased according to the increase in the mercury concentration in the exhaust gas, it may be increased linearly or stepwise.

In the present invention, when the activated carbon supply amount is controlled based on a predetermined correspondence relationship between the mercury concentration in the exhaust gas and the activated carbon supply amount, various forms can be taken for increasing the activated carbon supply amount from the minimum value to the maximum value. This is as explained in FIG. 3, but as an example of how to determine the predetermined minimum value and the predetermined maximum value, the case where the activated carbon supply amount is increased in the form of FIG. 3 (E) is as follows. Explain to. That is, the correspondence between the measured mercury concentration and the amount of activated carbon supplied is shown below. In the range from the measured value of the mercury concentration in the exhaust gas to zero or less than the measurable limit minimum value to the first predetermined mercury concentration, the activated charcoal is supplied under the predetermined minimum value of the activated charcoal supply amount. Then, after the measured value of the mercury concentration reaches the first predetermined mercury concentration, the amount of activated charcoal supplied is linearly increased from the predetermined minimum value as the mercury concentration in the exhaust gas increases, and the measured value of the mercury concentration is increased. When the second predetermined mercury concentration is reached, the activated charcoal supply amount is set to the predetermined maximum value, and after the activated charcoal supply amount is increased to the predetermined maximum value, the mercury concentration in the exhaust gas is increased. It is a form in which the amount of activated coal supplied is kept constant at the predetermined maximum value.

The inventors have examined various conditions for determining the above-mentioned predetermined minimum value and predetermined maximum value when treating exhaust gas containing mercury by using the exhaust gas treatment apparatus shown in FIG. In the examination, the mercury concentration in the exhaust gas at the inlet (upstream side) of the dust collector was measured, and the ratio of this mercury concentration measurement value to the set value of the mercury concentration in the exhaust gas on the downstream side of the dust collector ( When the upstream mercury concentration ratio) is changed in the range of 20 to 200 times, the mercury adsorption removal process using activated carbon is simulated to obtain an appropriate range of the predetermined minimum value and the predetermined maximum value of the activated carbon supply amount. It was. The upstream mercury concentration ratio was divided into a plurality of stages between 20 times and 200 times, and an appropriate range for a predetermined minimum value and a predetermined maximum value was determined in the range of each category. The results obtained are shown in Table 1.

In Table 1, for example, when it is predicted that the exhaust gas containing mercury whose upstream mercury concentration ratio is in the range of 100 times or more and less than 120 times is discharged from the furnace, it is defined as the activated carbon injection weight with respect to the treated exhaust gas flow rate. is a predetermined minimum value of the activated carbon supply amount is set to 60~200mg / Nm ^3, to set a predetermined maximum value of the activated carbon supply amount and 300~1000mg / Nm ^3.

In Table 1, for each category range of the upstream mercury concentration ratio, the lower limit of the predetermined minimum value is when the measured mercury concentration in the exhaust gas is low or when the mercury concentration set value on the downstream side of the dust collector is high. The upper limit of the predetermined minimum value corresponds to the case where the measured mercury concentration in the exhaust gas is high or the mercury concentration set value on the downstream side of the dust collector is low.

Further, in Table 1, for each category range of the upstream mercury concentration ratio, the lower limit of the predetermined maximum value is when the measured mercury concentration in the exhaust gas is low or the mercury concentration set value on the downstream side of the dust collector is high. Corresponding to the case, the upper limit of the predetermined maximum value corresponds to the case where the measured mercury concentration in the exhaust gas is high or the mercury concentration set value on the downstream side of the dust collector is low.

By setting a predetermined minimum value of the amount of activated carbon supplied in this way, the activated carbon is adhered to the bag filter of the dust collector and the adsorption layer is sufficiently formed in advance, and contains a high concentration of mercury. When the exhaust gas is discharged, the activated carbon adsorbed layer already formed and the activated carbon blown at that time can adsorb and remove mercury, and the mercury concentration can be lowered to a sufficiently low concentration.

Further, by setting a predetermined maximum value of the amount of activated carbon supplied, it is possible to sufficiently adsorb and remove high-concentration mercury without excessive supply of activated carbon.

Hereinafter, examples of the present invention will be described together with comparative examples.

[Comparison example]
A configuration different from that of the example will be described with respect to a comparative example with respect to the example using the exhaust gas treatment apparatus shown in FIG. 1 to be described later. Two exhaust gas channels are provided to guide the exhaust gas discharged from each of the two incinerators to the chimney by each route, and the amount of exhaust gas discharged from the waste incinerator is 10,000 Nm ^{3 each from the chimney.} The amount of supply is always constant from the activated carbon supply device provided in each exhaust gas flow path so that the concentration of mercury in the exhaust gas in the chimney is 50 μg / Nm ^{3 or less on average for one hour.} Activated carbon is blown at 5 kg / h. The mercury concentration in the exhaust gas upstream of the bug filter at regular times is 100 μg / Nm ³ . When a mercury concentration meter is installed upstream of the bag filter in each exhaust gas flow path and the mercury concentration measured by the mercury concentration meter ^{increases to 500 μg / Nm 3} or more, the mercury concentration upstream of the bag filter and activated charcoal shown in FIG. Based on the correspondence between the supply amounts, the amount of activated charcoal supplied is controlled to be increased in steps as the measured mercury concentration increases.

By variations in the dust properties supplied, although the mercury concentration in the exhaust gas in the bag filter upstream position rose to 1,600μg / Nm ^3, the mercury concentration in the exhaust gas in the chimney it was kept below 50 [mu] g / Nm ^3. The mercury concentration in the exhaust gas fluctuates due to fluctuations in the properties of the supplied waste, and after the measured value of mercury concentration at the upstream position of the bag filter exceeds ^{500 μg / Nm 3 during the period when the amount of activated carbon supplied in response to the fluctuation is controlled.} The amount of activated carbon supplied before the temperature dropped to less than 500 μg / Nm ^{3 was 0.33 kg.}

[Example 1]
In Example 1, the exhaust gas treatment apparatus shown in FIG. 1 was used to remove mercury from exhaust gas containing mercury, and the effect was confirmed. The mercury concentration of the exhaust gas confluent collected from the upstream position of the bug filter of each exhaust gas flow path is measured with one mercury concentration meter, and the correspondence between the exhaust gas confluence mercury concentration and the amount of activated carbon supplied shown in FIG. The amount of activated carbon supplied is controlled to be increased based on the above. When the measured mercury concentration value is ^{less than 300 μg / Nm 3, the} amount of activated charcoal supplied is 0.5 kg / h, and when the measured value of mercury concentration is 300 μg / Nm ³ or more, the amount of activated charcoal supplied increases as the measured value of mercury concentration increases. Is increased in steps so that the maximum value is 5 kg / h. In each exhaust gas flow path, the mercury concentration in the exhaust gas upstream of the bug filter at steady time is 100 μg / Nm ³ , but the mercury concentration in the exhaust gas upstream of the bag filter in one exhaust gas flow path is up to 500 μg / Nm ^3. When it rises, the ^{measured value of the mercury concentration meter of the confluence shows 300 μg / Nm 3} , so as shown in FIG. 5, when the measured value of mercury concentration is 300 μg / Nm ³ or more, the amount of activated carbon supplied is controlled to be increased. To do.

Due to fluctuations in the properties of the supplied waste, the measured mercury concentration of the confluence of exhaust gas collected from the upstream position of the bag filter in each exhaust gas flow path ^{increased to 1,600 μg / Nm 3} , but the maximum mercury concentration in the chimney. The value could be suppressed to 50 μg / Nm ^{3 or less.} When the mercury concentration in the exhaust gas fluctuates due to fluctuations in the properties of the supplied waste, the measured mercury concentration of the confluent is 300 μg during the period when the amount of activated carbon supplied is controlled for the fluctuation. / Nm ³ from beyond activated carbon amount supplied to the down to less than 300 [mu] g / Nm ³ was 0.56 kg. In the comparative example, two mercury densitometers were required, but one mercury densitometer was used to reduce the equipment cost.

[Example 2]
In Example 2, the exhaust gas treatment apparatus shown in FIG. 2 was used to remove mercury from the exhaust gas containing mercury, and the effect was confirmed. The mercury concentration of the confluence of exhaust gas collected from the upstream position of the bug filter in each exhaust gas flow path is measured with one first mercury concentration meter, and the correspondence between the measured mercury concentration value shown in FIG. 5 and the amount of activated carbon supplied. The first control is to increase the amount of activated carbon supplied based on the relationship. The first control is performed in the same manner as in the first embodiment, and a second mercury densitometer for measuring the mercury concentration in the exhaust gas is also provided at the downstream position of each bag filter, and the measured value by the second mercury densitometer is used. Based on this, the first control based on the mercury concentration measurement value by the first mercury concentration meter is complemented, and the second control is to increase or decrease the amount of activated carbon supplied.

Due to fluctuations in the properties of the supplied waste, the measured mercury concentration of the confluence of exhaust gas collected from the upstream position of the bag filter in each exhaust gas flow path ^{increased to 1,600 μg / Nm 3} , but the maximum mercury concentration in the chimney. The value could be suppressed to 50 μg / Nm ^{3 or less.} When the mercury concentration in the exhaust gas fluctuates due to fluctuations in the properties of the supplied waste, the measured mercury concentration of the confluent is 300 μg during the period in which the amount of activated carbon supplied is controlled for the fluctuation. The amount of activated carbon supplied from the time when it exceeded / Nm ³ to the time when ^{it decreased to less than 300 μg / Nm 3} was 0.46 kg, and the amount of activated carbon supplied could be reduced as compared with Example 1. In the comparative example, two mercury densitometers were required, but one mercury densitometer was used to reduce the equipment cost.

1A; 1B furnace (incinerator)
3A; 3B dust collector (bug filter)
5A; 5B Activated carbon supply device 7 Mercury concentration measuring device (first mercury concentration meter)
8 Control device 9A; 9B Second mercury concentration meter

Claims (14)

In order to treat the exhaust gas containing mercury discharged from multiple furnaces, in each exhaust gas flow path that guides the exhaust gas discharged from each furnace, a dust collector that removes the exhaust gas and an upstream side of the dust collector In an exhaust gas treatment device provided with an activated carbon supply device that blows activated carbon into each exhaust gas flow path.
Mercury concentration measurement that measures the mercury concentration of the confluence of exhaust gas collected from the exhaust gas flow path on the downstream side of the furnace and on the upstream side of the dust collector in each exhaust gas flow path on the upstream side of the activated carbon injection position. It is equipped with a device and a control device for controlling the amount of activated carbon supplied by a plurality of activated carbon supply devices.
The control device controls the amount of activated carbon supplied so that the concentration of activated carbon in the exhaust gas on the downstream side of the dust collector is equal to or less than the set value based on the value measured by the mercury concentration measuring device. An exhaust gas treatment device characterized by. In order to treat the exhaust gas containing mercury discharged from multiple furnaces, in each exhaust gas flow path that guides the exhaust gas discharged from each furnace, a dust collector that removes the exhaust gas and an upstream side of the dust collector In an exhaust gas treatment device provided with an activated carbon supply device that blows activated carbon into each exhaust gas flow path.
Upstream mercury that measures the mercury concentration of the confluence of exhaust gas collected from the exhaust gas flow path on the downstream side of the furnace and on the upstream side of the dust collector in each exhaust gas flow path on the upstream side of the activated carbon injection position. A mercury concentration measuring device having a densitometer and a downstream mercury concentration meter for measuring the mercury concentration in the exhaust gas on the downstream side of the dust collector in each exhaust gas flow path, and a control for controlling the activated carbon supply amount of the activated carbon supply device. Equipped with equipment,
The control device sets the mercury concentration in the exhaust gas on the downstream side of the dust collector based on the mercury concentration measurement value by the upstream mercury concentration meter and the mercury concentration measurement value by the downstream mercury concentration meter for the amount of activated carbon supplied. An exhaust gas treatment device characterized by controlling the amount of activated carbon supplied as follows. In order to treat the exhaust gas containing mercury discharged from multiple furnaces, in each exhaust gas flow path that guides the exhaust gas discharged from each furnace, a dust collector that removes the exhaust gas and an upstream side of the dust collector In an exhaust gas treatment device provided with an activated carbon supply device that blows activated carbon into each exhaust gas flow path.
Upstream mercury that measures the mercury concentration of the confluence of exhaust gas collected from the exhaust gas flow path on the downstream side of the furnace and on the upstream side of the dust collector in each exhaust gas flow path on the upstream side of the activated carbon injection position. It is equipped with a densitometer, a downstream mercury densitometer that measures the mercury concentration in the exhaust gas on the downstream side of the dust collector in each exhaust gas flow path, and a control device that controls the amount of activated carbon supplied by a plurality of activated carbon supply devices.
The control device is the first control that controls the amount of activated carbon supplied based on the mercury concentration measurement value by the upstream mercury concentration meter, and the control device on the downstream side of each dust collector based on the mercury concentration measurement value by the downstream mercury concentration meter. An exhaust gas treatment device characterized in that a second control for controlling the amount of activated carbon supplied is performed so that the mercury concentration in the exhaust gas of the above is less than or equal to a set value. The exhaust gas treatment device according to claim 1, wherein the control device is controlled so as to maintain the amount of activated carbon supplied to a predetermined minimum value or more. One of claims 1 to 4, wherein the control device controls the amount of activated carbon supplied so as to keep the amount of activated carbon supplied at a predetermined maximum value when the mercury concentration measured value by the mercury concentration measuring device is equal to or higher than a predetermined mercury concentration. The exhaust gas treatment device described in 1. The control device has a predetermined minimum value of activated carbon in the range from the value measured by the mercury concentration measuring device in the exhaust gas to zero or less than the measurable limit minimum value to reach the first predetermined mercury concentration. Activated charcoal is supplied based on the supply amount, and after the mercury concentration measurement value reaches the first predetermined mercury concentration, the activated charcoal supply amount is linearly increased from the predetermined minimum value as the mercury concentration measurement value increases. Then, when the measured mercury concentration reaches the second predetermined mercury concentration, the amount of activated charcoal supplied is set to the predetermined maximum supply amount, and after the measured mercury concentration reaches the second predetermined mercury concentration, The exhaust gas treatment apparatus according to one of claims 1 to 5, wherein the amount of activated coal supplied is kept constant at a predetermined maximum value with respect to an increase in the measured mercury concentration value. The control device has a predetermined minimum value in the range from the value measured by the mercury concentration measuring device in the exhaust gas to zero or less than the measurable limit minimum value to reach the first predetermined mercury concentration. Activated carbon is supplied based on the activated carbon supply amount as one supply amount, and when the measured mercury concentration reaches the first predetermined mercury concentration, the activated carbon supply amount is stepwise set to the predetermined second supply amount. In the range until the measured mercury concentration reaches the second predetermined mercury concentration, the amount of activated carbon supplied is kept constant at the second supply, and the measured mercury concentration is the second predetermined mercury. When the concentration is reached, the amount of activated carbon supplied is repeatedly increased stepwise as the measured mercury concentration increases so that the amount of activated carbon supplied is increased to a predetermined third supply amount. Is one of claims 1 to 5, wherein the amount of activated carbon supplied is kept constant at the predetermined maximum value with respect to the increase in the measured mercury concentration value. Exhaust gas treatment device according to. In order to treat the exhaust gas containing mercury discharged from a plurality of furnaces, the exhaust gas is dust-removed by a dust collector in each exhaust gas flow path that guides the exhaust gas discharged from each furnace, and each is discharged on the upstream side of the dust collector. In the exhaust gas treatment method in which activated carbon is blown into the exhaust gas flow path from the activated carbon supply device,
The mercury concentration of the confluence of exhaust gas collected from the exhaust gas flow path at the position downstream of the furnace and upstream side of the dust collector in each exhaust gas flow path is measured by the mercury concentration measuring device on the upstream side of the activated carbon injection position. It was decided to measure and control the amount of activated carbon supplied by multiple activated carbon supply devices with a control device.
The control device controls the amount of activated carbon supplied so that the concentration of activated carbon in the exhaust gas on the downstream side of the dust collector is equal to or less than the set value based on the value measured by the mercury concentration measuring device. An exhaust gas treatment method characterized by. In order to treat the exhaust gas containing mercury discharged from a plurality of furnaces, the exhaust gas is dust-removed by a dust collector in each exhaust gas flow path that guides the exhaust gas discharged from each furnace, and each is discharged on the upstream side of the dust collector. In the exhaust gas treatment method in which activated carbon is blown into the exhaust gas flow path from the activated carbon supply device,
Upstream mercury that measures the mercury concentration of the confluence of exhaust gas collected from the exhaust gas flow path on the downstream side of the furnace and on the upstream side of the dust collector in each exhaust gas flow path on the upstream side of the injection position of the activated charcoal. The mercury concentration is measured by a densitometer and a mercury concentration measuring device having a downstream mercury concentration meter that measures the mercury concentration in the exhaust gas on the downstream side of the dust collector in each exhaust gas flow path.
It was decided to control the amount of activated carbon supplied by multiple activated carbon supply devices.
With the control device, the amount of activated carbon supplied is set based on the mercury concentration measurement value by the upstream mercury concentration meter and the mercury concentration measurement value by the downstream mercury concentration meter, and the mercury concentration in the exhaust gas on the downstream side of the dust collector is set. An exhaust gas treatment method characterized by controlling the amount of activated carbon supplied as follows. In order to treat the exhaust gas containing mercury discharged from a plurality of furnaces, the exhaust gas is dust-removed by a dust collector in each exhaust gas flow path that guides the exhaust gas discharged from each furnace, and each is discharged on the upstream side of the dust collector. In the exhaust gas treatment method in which activated carbon is blown into the exhaust gas flow path from the activated carbon supply device,
Upstream mercury that measures the mercury concentration of the confluence of exhaust gas collected from the exhaust gas flow path on the downstream side of the furnace and on the upstream side of the dust collector in each exhaust gas flow path on the upstream side of the injection position of the activated charcoal. The mercury concentration is measured by a densitometer and a mercury concentration measuring device having a downstream mercury concentration meter that measures the mercury concentration in the exhaust gas on the downstream side of the dust collector in each exhaust gas flow path.
It was decided to control the amount of activated carbon supplied by multiple activated carbon supply devices.
The control device performs the first control to control the amount of activated charcoal supply based on the mercury concentration measurement value by the upstream mercury concentration meter, and the downstream side of each dust collector based on the mercury concentration measurement value by the downstream mercury concentration meter. A method for treating an exhaust gas, which comprises performing a second control for controlling the amount of activated coal supplied so that the mercury concentration in the exhaust gas in the above is less than or equal to a set value.
The exhaust gas treatment method according to claim 8, wherein the control device controls so as to maintain the amount of activated carbon supplied to a predetermined minimum value or more. One of claims 8 to 11, wherein the control device controls the amount of activated carbon supplied so as to keep the amount of activated carbon supplied at a predetermined maximum value when the mercury concentration measured value by the mercury concentration measuring device is equal to or higher than a predetermined mercury concentration. The exhaust gas treatment method described in 1. The control device has a predetermined minimum value of activated carbon in the range from the value measured by the mercury concentration measuring device in the exhaust gas to zero or less than the measurable limit minimum value to reach the first predetermined mercury concentration. Activated charcoal is supplied based on the supply amount, and after the mercury concentration measurement value reaches the first predetermined mercury concentration, the activated charcoal supply amount is linearly increased from the predetermined minimum value as the mercury concentration measurement value increases. Then, when the measured mercury concentration reaches the second predetermined mercury concentration, the amount of activated charcoal supplied is set to the predetermined maximum supply amount, and after the measured mercury concentration reaches the second predetermined mercury concentration, The exhaust gas treatment method according to one of claims 8 to 12, wherein the amount of activated coal supplied is kept constant at a predetermined maximum value with respect to an increase in the measured mercury concentration value. The control device has a predetermined minimum value in the range from the value measured by the mercury concentration measuring device in the exhaust gas to zero or less than the measurable limit minimum value to reach the first predetermined mercury concentration. Activated carbon is supplied based on the activated carbon supply amount as one supply amount, and when the measured mercury concentration reaches the first predetermined mercury concentration, the activated carbon supply amount is stepwise set to the predetermined second supply amount. In the range until the measured mercury concentration reaches the second predetermined mercury concentration, the amount of activated carbon supplied is kept constant at the second supply, and the measured mercury concentration is the second predetermined mercury. When the concentration is reached, the amount of activated carbon supplied is repeatedly increased stepwise as the measured mercury concentration increases so that the amount of activated carbon supplied is increased to a predetermined third supply amount. Is one of claims 8 to 12, wherein the amount of activated carbon supplied is kept constant at the predetermined maximum value with respect to the increase in the measured mercury concentration value. The exhaust gas treatment method described in 1.

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