JP6928544B2 - Fluidized bed monitoring method and equipment - Google Patents

Description

The present invention relates to a technique for monitoring the state of a fluidized bed in a fluidized bed furnace.

Conventionally, a fluidized bed furnace has been known in which a fluidized bed formed by flowing a fluidized medium filled in the lower part of the furnace with a fluidized gas blown from the bottom of the furnace is formed. In a fluidized bed furnace, it is generally not possible to visually check the state of the fluidized bed during operation. Therefore, a technique has been proposed in which the state of the fluidized bed is detected by using a sensor or the like during the operation of the fluidized bed furnace.

For example, in Patent Document 1, two or more pressure sensors are arranged at different positions along the surface of the inner wall of the furnace at different depths of the fluidized bed, and the height of the fluidized bed is based on the measured values obtained by the pressure sensors. It is stated to detect the level.

Further, for example, in Patent Document 2, pressure outlet holes are provided at two points having different heights in the fluidized bed, the pressure difference between the two points is measured, and the particle shape of the fluidized material is determined from the temporal change of those values. It is described to indirectly predict the increase (deterioration) of.

Further, for example, in Patent Document 3, a plurality of temperature sensors dispersedly arranged in the depth direction and a plurality of temperature sensors dispersedly arranged in the arrangement direction of the air boxes arranged in the lower part of the furnace in the fluidized bed. It is described that a temperature sensor is provided and a local flow failure site of the flow bed is identified from the temperature distribution obtained from the temperature sensors.

Japanese Unexamined Patent Publication No. 3-105193 Japanese Unexamined Patent Publication No. 7-19413 Japanese Unexamined Patent Publication No. 2007-271203

By the way, in the above-mentioned fluidized bed furnace, the fuel is partially burned (gasified) in the fluidized bed under a low air ratio condition of, for example, 0.2 to 0.6. In combustion under such a low air ratio condition, a large amount of unburned char (unburned carbon), which is unburned fuel, is generated in the fluidized bed. In general, the specific gravity of unburned char is smaller than the specific gravity of a fluidized medium (for example, silica sand), so when the proportion of unburned char in the fluidized bed increases, the volume of the fluidized bed expands and the density decreases, resulting in flow characteristics. May worsen.

Further, in a fluidized bed furnace, when a mixture of a plurality of materials including an oxygen occlusion / release material such as ylmenite (Fe-based) and a carbon gasification promoting material such as Ni ore is used as a fluidized bed, the fluidized bed is used. If the proportion of the gasification promoting material in the above is excessive, the volume of the fluidized bed expands, the density decreases, and the fluidized characteristics may deteriorate.

Further, in a fluidized bed furnace, a mixture of a plurality of materials including silica sand and an anti-aggregation agent composed of a material (porous substance such as zeolite or calcium oxide) that absorbs an alkaline component of silica sand is used as a fluidized bed. In this case, if the proportion of the antiaggregating agent in the fluidized bed becomes excessive, the volume of the fluidized bed expands, the density decreases, and the fluidized characteristics may deteriorate.

As described above, it is known that the flow characteristics of the fluidized bed deteriorate due to the increase (excess) of flow-inhibiting factors such as unburned carbon, gasification promoting material, and anti-aggregation agent contained in the fluidized bed, and it is avoided. To this end, it is useful to monitor the proportion of fluidized beds in the fluidized bed. Therefore, the present invention proposes an apparatus and a method for monitoring the ratio of flow-inhibiting factors contained in the fluidized bed of a fluidized bed furnace.

The fluidized bed monitoring method according to one aspect of the present invention is a method for monitoring a fluidized bed in a fluidized bed furnace in which a fluidized bed formed by flowing a fluidized bed filled in the lower part of the furnace with a fluidized gas blown from the bottom of the furnace. A fluidized bed monitoring method that monitors the condition,
A segment in the height direction is defined in the fluidized bed, and the pressure difference between the upper end level and the lower end level of the segment is detected.
Based on the detected pressure difference, the proportion of the flow inhibitor contained in the segment, which reduces the fluidity of the fluidized bed by reducing the density of the fluidized bed, was determined.
It is characterized in that the ratio of the fluidized bed factor is monitored during the operation of the fluidized bed furnace.

Here, for example, the flow is based on the difference between the detected pressure difference and the pressure difference reference value, which is the pressure difference between the upper end level and the lower end level of the segment in a state where fuel is not supplied to the fluidized bed. The proportion of the inhibitor can be determined.

Further, the fluidized bed monitoring device according to one aspect of the present invention is the fluidized bed furnace in which a fluidized bed formed by flowing a fluidized medium filled in the lower part of the furnace with a fluidized gas blown from the bottom of the furnace. A fluidized bed monitoring device that monitors the condition of the floor.
A segment in the height direction is defined in the fluidized bed.
A pressure sensor provided on the inner wall of the fluidized bed furnace in contact with the fluidized bed to detect the pressure difference between the upper end level and the lower end level of the segment.
Based on the detected pressure difference, a calculation unit for obtaining the ratio of a flow inhibitor containing in the segment to reduce the fluidity of the fluidized bed by reducing the density of the fluidized bed, and
It is characterized by including a monitoring unit that monitors the ratio of the fluidized bed factor during the operation of the fluidized bed furnace.

Here, for example, the calculation unit determines the pressure difference reference value, which is the pressure difference between the upper end level and the lower end level of the segment in a state where fuel is not supplied to the fluidized bed, and the detected pressure difference. From the difference, the ratio of the flow inhibitory factor can be obtained.

According to the above-mentioned fluidized bed monitoring method and apparatus, it is possible to monitor the ratio of flow-inhibiting factors such as unburned carbon (including unburned char) in the fluidized bed during operation of the fluidized bed furnace. Then, based on the change in the ratio of the fluidized bed in the fluidized bed, it is possible to predict the deterioration of the flow characteristics of the fluidized bed due to the increase in the ratio of the fluidized bed in the fluidized bed. As a result, it is possible to perform appropriate treatment before the deterioration of the flow characteristics of the fluidized bed and avoid the deterioration of the flow characteristics of the fluidized bed.

In the fluidized bed monitoring method, the proportion of the fluidized bed factor is determined in two or more segments having different height levels, and the proportion of the fluidized bed factor in the two or more segments is monitored during the operation of the fluidized bed furnace. You can do it.

Similarly, in the fluidized bed monitoring device, the calculation unit obtains the ratio of the fluidized bed factor in two or more of the segments having different height levels, and the monitoring unit obtains 2 during the operation of the fluidized bed furnace. The proportion of the fluidized bed factor in the above segment may be monitored.

According to the above-mentioned fluidized bed monitoring method and apparatus, it is possible to monitor the ratio of fluidized bed flow-inhibiting factors at a plurality of positions having different height levels of the fluidized bed.

In the fluidized bed monitoring method, if a local increase in the proportion of the fluidized bed in the fluidized bed is found from the proportion of the fluidized bed in the two or more segments, a predetermined treatment may be performed.

Similarly, in the fluidized bed monitoring device, the monitoring unit determines that a local increase in the proportion of the fluidized bed in the fluidized bed is found from the proportion of the fluidized bed in the two or more segments. Processing may be performed.

According to the above-mentioned fluidized bed monitoring method and apparatus, it is possible to prevent deterioration of the fluidized bed's flow characteristics by detecting an increase in the proportion of local fluidized bed in the fluidized bed and taking measures according to the situation. Can be done.

In the fluidized bed monitoring method, if an increase in the overall proportion of the fluidized bed of the fluidized bed is found from the proportion of the fluidized bed in the two or more segments, a predetermined treatment may be performed.

Similarly, in the fluidized bed monitoring device, the monitoring unit determines that an increase in the overall proportion of the fluidized bed of the fluidized bed is found from the proportion of the fluidized bed in the two or more segments. Processing may be performed.

According to the above-mentioned fluidized bed monitoring method and apparatus, it is possible to prevent deterioration of the fluidized bed's flow characteristics by detecting an increase in the proportion of the overall fluidized bed in the fluidized bed and taking measures according to the situation. Can be done.

According to the present invention, the ratio of the fluidized bed contained in the fluidized bed of the fluidized bed furnace can be monitored.

FIG. 1 is a block diagram showing a schematic configuration of a combustion system including a fluidized bed furnace according to an embodiment of the present invention. FIG. 2 is a diagram showing a schematic configuration of a fluidized bed furnace according to an embodiment of the present invention. FIG. 3 is an enlarged view of the fluidized bed portion of the fluidized bed furnace. FIG. 4 is a diagram showing a configuration of a fluidized bed monitoring device. FIG. 5 is a chart showing the relationship between the unburned carbon concentration and the differential pressure in a certain segment.

[Combustion system 100 configuration]
First, the configuration of the combustion system 100 including the fluidized bed furnace 1 according to the embodiment of the present invention will be described. The combustion system 100 shown in FIG. 1 is a system that burns fuel (combustion target) such as coal, biomass, RDF, municipal waste, and industrial waste, and recovers the exhaust heat thereof.

The combustion system 100 includes a fluidized bed furnace 1 that burns fuel. The combustion exhaust gas system 3 of the fluidized bed furnace 1 is provided with a heat exchange device 31, a cyclone type dust collector 32, a bag filter 33, and an attraction blower 34 which is an attraction fan. Exhaust heat from the combustion exhaust gas of the fluidized bed furnace 1 is recovered by the heat exchange device 31, dust is separated by the cyclone type dust collector 32 and the bag filter 33, and a part of the dust is discharged to the outside of the system through a chimney (not shown) by the attraction blower 34. Will be done.

An exhaust gas recirculation system 4 is connected to the downstream side of the bug filter 33 of the combustion exhaust gas system 3. The exhaust gas recirculation system 4 is provided with a gas recirculation blower 40, and a part of the combustion exhaust gas of the combustion exhaust gas system 3 is returned to the fluidized bed furnace 1 by the gas recirculation blower 40. The combustion exhaust gas returned to the flow bed furnace 1 by the exhaust gas recirculation system 4 is used as a flow gas (primary combustion gas), a secondary combustion gas, and a tertiary combustion gas.

[Structure of fluidized bed furnace 1]
Next, the configuration of the fluidized bed furnace 1 according to the embodiment of the present invention will be described. The fluidized bed furnace 1 shown in FIG. 2 has a furnace body 10 provided with a combustion chamber including a fluidized bed portion 11 at the bottom of the furnace and a freeboard portion 12 above the fluidized bed portion 11, and an operation control device for controlling the operation of the fluidized bed furnace 1. A fluidized bed monitoring device 9 and a fluidized bed monitoring device 9 are provided. At the lower part of the freeboard portion 12, there is a throttle portion 13 in which the cross-sectional area of the gas passage is narrowed as compared with the remaining portion of the combustion chamber. In the freeboard section 12, the combustion gas flows from the bottom to the top, and a heat transfer tube constituting the heat exchange device 31 is installed in the flue connected to the upper part of the freeboard section 12.

FIG. 3 is an enlarged view of the fluidized bed portion 11. As shown in FIGS. 2 and 3, the fluidized bed portion 11 is filled with a fluidized bed 51 such as silica sand, and a fluidized gas supply device 52 that supplies fluidized gas to the fluidized bed 51 from the bottom thereof. An internal circulating fluidized bed is formed by partition walls 41, 42 that partition the fluidized bed 51 into three cells 61, 62, 63.

The first partition wall 41 partitions the lower portion of the furnace body 10 including the fluidized bed portion 11 into a combustion region 53 and a heat recovery region 54. The second partition wall 42 is provided in the heat recovery region 54 in the vicinity of the first partition wall 41 and in parallel with the first partition wall 41. By these partition walls 41 and 42, the fluidized bed portion 11 is a "combustion cell 61" formed between the first side wall 10a of the furnace body 10 and the first partition wall 41, and the first partition wall 41 and the second. In three cells, a "circulation cell 62" formed between the partition wall 42 and a "heat collecting cell 63" formed between the second partition wall 42 and the second side wall 10b of the furnace body 10. It is partitioned. The heat collecting cell 63 is provided with a heat transfer tube 64 such as a superheater tube or an evaporator tube. Heat recovery is performed by the heat medium passing through the heat transfer tube 64.

Above the combustion region 53, a combustion chamber extending linearly in the vertical direction is formed. On the other hand, above the heat recovery area 54, a ceiling wall 43 that closes the upper part of the heat recovery area 54 is provided. The upper end of the first partition wall 41 is close to the ceiling wall 43, and an upper communication port serving as an unburned gas supply port 68 is formed between the upper end of the first partition wall 41 and the ceiling wall 43. The lower end of the first partition wall 41 is higher than the lower end of the second partition wall 42, whereby a lower communication port 55 through which the flow medium flows is formed below the first partition wall 41. Further, at the upper and lower portions of the second partition wall 42, communication ports 56 and 57 are formed in which the circulation cell 62 and the heat collecting cell 63 are communicated with each other and the flow medium is circulated.

The flow gas supply device 52 supplies the flow gas whose flow rate is adjusted independently to each of the combustion cell 61, the circulation cell 62, and the heat collection cell 63. At the bottom of each of the combustion cell 61, the circulation cell 62, and the heat collecting cell 63, one or more air diffusers 80 having a large number of air outlets opened sideways are provided. Each air diffuser 80 is arranged below the lower ends of the first partition wall 41 and the second partition wall 42. However, the flow gas supply device 52 replaces the air diffuser pipe 80 with a wind box arranged at the bottom of each cell 61, 62, 63 and a gas dispersion plate provided so as to close the upper part of the wind box. It may be provided (all are not shown).

The air diffuser pipe 80 is connected to each cell 61, 62, 63 by a header, and each header is provided with flow rate adjusting means 81a, 82a, 83a such as a damper (or valve) and a flow meter 81b, 82b, 83b. Gas supply pipes 81, 82, 83 are connected. To the flow gas supply pipe 81 connected to the air diffuser pipe 80 arranged at the bottom of the combustion cell 61 and the flow gas supply pipe 82 connected to the air diffuser pipe 80 arranged at the bottom of the circulation cell 62. Air is supplied by the indentation blower 79. Further, the exhaust gas recirculation system 4 is connected to the flow gas supply pipe 83 connected to the air diffuser pipe 80 arranged at the bottom of the heat collecting cell 63.

The operation control device 15 supplies each fluidized gas based on the detected values of the temperature sensor (not shown) and the flowmeters 81b, 82b, 83b, etc. that detect the temperatures of the combustion cell 61 and the heat collecting cell 63 in the fluidized bed 51. The flow rate adjusting means 81a, 82a, 83a are operated so as to adjust the flow rate of the fluidized gas in the pipes 81, 82, 83. Air is blown out as a flowing gas from the bottoms of the combustion cell 61 and the circulation cell 62, and combustion exhaust gas is blown out as a flowing gas from the bottom of the heat collecting cell 63.

Here, the superficial velocity of the flow gas in the combustion cell 61 is larger than the superficial velocity of the flow gas in the heat collecting cell 63, and the superficial velocity of the flow gas in the circulation cell 62 is that of the combustion cell 61. The flow rate of the flow gas is adjusted so as to be larger than the superficial velocity of the flow gas and the superficial velocity of the flow gas in the heat collecting cell 63. As a result, the flow medium of the combustion cell 61 moves to the circulation cell 62 through the lower communication port 55 of the first partition wall 41, and the flow medium of the circulation cell 62 passes through the upper communication port 56 of the second partition wall 42. A flow of the flow medium is generated so as to move to the heat collection cell 63 and the flow medium of the heat collection cell 63 circulates to the combustion cell 61 and the circulation cell 62 through the lower communication port 57 of the second partition wall 42. By such circulation of the fluid medium, the heat energy of the fluid medium that has become hot in the combustion cell 61 is taken out in the heat collecting cell 63, and the fluid medium whose temperature has decreased is returned to the combustion cell 61. , The temperature rise of the flow medium of the combustion cell 61 is suppressed.

In the freeboard portion 12, a fuel inlet 65 is opened in the first side wall 10a, which is immediately above the surface layer portion of the fluidized bed portion 11 during operation. The fuel inlet 65 is located on the upstream side of the flow of combustion gas with respect to the throttle portion 13. Fuel is supplied to the fuel inlet 65 by a fuel supply device (not shown). The fuel charged into the furnace from the fuel inlet 65 falls to the upper part of the combustion cell 61 of the fluidized bed portion 11.

In the freeboard section 12, an unburned gas supply port 68 is opened in the furnace wall on the downstream side of the flow of combustion gas from the fuel inlet 65 and around the throttle section 13. From the unburned gas supply port 68, the air-fuel mixture of air and combustion exhaust gas is blown into the fluidized bed 51 from the air diffuser pipe 80 arranged in the fluidized bed 51 of the heat recovery region 54 and passed through the fluidized bed 51. , Blow out as a secondary combustion gas. However, in addition to the unburned gas supply port 68, a supply port for blowing out the secondary combustion gas may be provided.

In the freeboard section 12, a plurality of tertiary combustion gas supply ports 69 are opened in the furnace wall on the downstream side of the combustion gas flow from the unburned gas supply port 68. The plurality of tertiary combustion gas supply ports 69 are dispersedly provided at a plurality of height positions. Further, a temperature sensor 70 is provided on the furnace wall included in the diffusion region of the tertiary air blown out from the tertiary combustion gas supply port 69.

The air content of the tertiary combustion gas is adjusted by mixing the combustion exhaust gas with the air. Therefore, flow rate adjusting means 88 and 89 such as dampers (or valves) are provided in the air supply path to the tertiary combustion gas supply port 69 and the combustion exhaust gas supply path. When the temperature detected by the temperature sensor 70 at a certain location exceeds a predetermined range, the operation control device 15 maintains the flow rate of the tertiary combustion gas at a predetermined flow rate and supplies the tertiary combustion gas to that location. Flow rate adjusting means 88, 89 so that the air content of the gas decreases and, when the detected temperature falls below a predetermined range, the air content of the tertiary combustion gas supplied to the location increases. Adjust the opening of.

[Operation method of fluidized bed furnace 1]
Here, the operation method of the fluidized bed furnace 1 having the above configuration will be described. In the fluidized bed furnace 1, low air ratio combustion is performed in the fluidized bed portion 11. More specifically, the air ratio (that is, the primary air ratio) of the combustion cell 61 of the fluidized floor portion 11 and the fuel input while setting the total air ratio of the fluidized floor portion 11 and the free board portion 12 to a value larger than 1. The amount of fluidized air and secondary combustion gas supplied to the combustion cell 61 and / or its so that the air ratio (secondary air ratio) around the mouth 65 is a low air ratio of less than 1. The air content is adjusted. Desirably, the primary air ratio is lower than the secondary air ratio. For example, when the total air ratio of the fluidized bed portion 11 and the free board portion 12 is 1.2, the primary air ratio may be 0.4 and the secondary air ratio may be 0.8.

In the fluidized bed 11 in a reducing atmosphere with a low oxygen concentration, flammable pyrolysis gas and pyrolysis residue are produced by the slow drying and thermal decomposition of the fuel. The thermal decomposition residue and the unburned residue of the fuel are the bottom of the combustion cell 61, and the furnace is provided from the outlet 72 of the flow medium and the incombustible material provided at an intermediate position between the first side wall 10a and the first partition wall 41. It is discharged to the outside. The pyrolysis gas generated in the fluidized floor portion 11 is burned by the secondary combustion gas, and the unburned portion in the combustion gas is completely burned by the tertiary combustion gas in the free board portion 12, and the combustion exhaust gas is the combustion exhaust gas. It is discharged to the system 3.

In the combustion cell 61 of the fluidized bed furnace 1 according to the above configuration, since the fuel is burned at a low air ratio, the unburned portion (unburned char) of the fuel in the combustion cell 61 is compared with the case where the air ratio is 1 or more. The ratio is large. When the primary air ratio is 0.4 as in the above example, the ratio of unburned char in the combustion cell 61 is particularly high as compared with the case where the conventional air ratio is about 0.8 to 0.9. growing. As the proportion of unburned char in the combustion cell 61 increases, the density of the unburned char is lower than that of the fluidized bed, so that the density of the fluidized bed 51 decreases. When the density of the fluidized bed 51 decreases, the volume of the fluidized bed 51 may expand and the fluidized characteristics may deteriorate.

Further, when the proportion of unburned char in the combustion cell 61 increases, the unburned char may flow into the heat collecting cell 63 due to the circulation of the fluid medium. In the heat collecting cell 63, it is desirable that unburned carbon does not exist in the fluidized bed 51, or even if it exists, its proportion is extremely small.

Therefore, in the fluidized bed furnace 1, the fluidized bed monitoring device 9 is provided to monitor the ratio of unburned carbon (including unburned char) in the fluidized bed 51 with respect to the combustion cell 61 and the heat collecting cell 63 of the fluidized bed portion 11. Therefore, the treatment is performed according to the proportion of unburned carbon. There may be a plurality of types of flow inhibiting factors that reduce the fluidity of the fluidized bed 51 by reducing the density of the fluidized bed 51, and here, the ratio of unburned carbon, which is one of them, is monitored. .. Hereinafter, the fluidized bed monitoring device 9 and the fluidized bed monitoring method performed by the device 9 will be described in detail.

[Fluidized bed monitoring device 9]
FIG. 4 is a diagram showing the configuration of the fluidized bed monitoring device 9. In FIG. 4, one of the plurality of segments S is highlighted. As shown in FIG. 4, the fluidized bed monitoring device 9 includes a plurality of pressure sensors 91, a calculation unit 92, and a monitoring unit 93.

The plurality of pressure sensors 91 are provided on the inner wall of the furnace body 10 of the fluidized bed furnace 1 in contact with the fluidized bed 51 of the fluidized bed portion 11, and are arranged at different height levels. The plurality of pressure sensors 91 can measure the pressure difference between two different height levels. In the present embodiment, a plurality of pressure sensors 91 are arranged at equal intervals in the height direction on the furnace wall of the fluidized bed portion 11. Then, one segment S is located between the height levels of the two pressure sensors 91 adjacent to each other in the height direction, and each segment S is used by using the pressure detection value at the upper end level and the pressure detection value at the lower end level of each segment S. The pressure difference between the upper end level and the lower end level of the above (hereinafter referred to as "differential pressure of segment S") is measured. However, instead of the plurality of pressure sensors 91, one or a plurality of differential pressure sensors that detect the differential pressure of the segment S with a pair of probes arranged at the upper end level and the lower end level of the segment S may be used.

The arithmetic unit 92 is a so-called computer, which includes a processor, a memory, a communication interface, and the like (both are not shown), and the processor executes a predetermined program stored in the memory to form the arithmetic unit 92. Demonstrate the function of. The communication interface receives detection signals from a plurality of pressure sensors 91 by using wireless or wired communication means by being controlled by a processor, and also transmits / receives data to / from a monitoring unit 93 and the like.

The calculation unit 92 acquires the detection signals of the plurality of pressure sensors 91, and obtains the differential pressure of each segment S from the detection values of the plurality of pressure sensors 91. However, as described above, when a differential pressure sensor is used instead of the plurality of pressure sensors 91, the detected value of each differential pressure sensor may be acquired as the differential pressure of the segment S.

Further, the calculation unit 92 obtains the unburned carbon ratio of the segment S from the differential pressure of the segment S for each segment S. The unburned carbon ratio of the segment S can be expressed as a function of the differential pressure of the segment S and the flow velocity (superficial velocity) of the flow gas of the target cell.

FIG. 5 is a chart showing the relationship between the unburned carbon concentration [wt%] and the differential pressure [kPa] in a certain segment S. In this chart, the relationship between the unburned carbon concentration of the segment S and the differential pressure is shown when the flow velocity f of the flow gas of the target cell is F1, F2, F3 (F1> F2> F3). The unburned carbon concentration [wt%] is represented by the weight of unburned carbon / (weight of fluid medium + weight of unburned carbon) × 100 in the target segment S. The unburned carbon concentration of the segment S decreases as the differential pressure of the segment S increases. In other words, the unburned carbon concentration in the segment S increases as the differential pressure in the segment S decreases. This is because the unburned carbon content has a lower specific gravity than the silica sand, so that when the unburned carbon concentration of the segment S increases, the weight of the flow medium of the segment S is compared with the state where the unburned carbon concentration is lower than that. As a result, the differential pressure (differential pressure) of the segment S decreases.

The calculation unit 92 calculates the unburned carbon concentration from the detected differential pressure of the segment S based on the relationship between the unburned carbon concentration of the segment S and the differential pressure as described above. The relationship between the unburned carbon concentration of the segment S and the differential pressure is obtained in advance by an experiment or a simulation and stored in the calculation unit 92.

Instead of the above-mentioned method for calculating the unburned carbon ratio, the calculation unit 92 of the segment S in a state where the unburned carbon concentration of the segment S is zero (that is, a state in which fuel is not supplied to the fluidized floor portion 11). The "pressure difference reference value", which is the differential pressure, is obtained and stored in advance by an experiment or simulation, and the unburned carbon ratio of the segment S is calculated from the difference between the detected differential pressure of the segment S and the pressure difference reference value. It may be configured as desired.

The monitoring unit 93 is a so-called computer, which includes a processor, a memory, a communication interface, and the like (both are not shown), and the processor executes a predetermined program stored in the memory to serve as the monitoring unit 93. Demonstrate the function of. The communication interface is controlled by a processor to transmit and receive data to and from the monitoring unit 93, the operation control device 15, and the like by using wireless or wired communication means.

The monitoring unit 93 acquires the unburned carbon ratio of each segment S obtained by the calculation unit 92, and monitors the value of the unburned carbon ratio of the fluidized bed furnace 1 during operation and its change. Further, when a predetermined state is detected during monitoring, the monitoring unit 93 transmits a warning and its measures to the operation control device 15.

For example, when the monitoring unit 93 detects that the unburned carbon ratio exceeds a predetermined threshold value in the segment S included in the range from the surface layer of the fluidized bed 51 to 1/3 of the height dimension of the fluidized bed 51, the fluidized bed 93 flows. Since it is estimated that excess unburned carbon is floating in the layer 51, a signal is sent to the operation control device 15 so as to reduce the amount of fuel input.

For example, when the monitoring unit 93 detects that the unburned carbon ratio exceeds a predetermined threshold value in the segment S included in the range of 1/3 of the height dimension of the fluidized bed 51 from the bottom of the fluidized bed 51, the fluidized bed 93 flows. Since it is estimated that excess unburned carbon is retained in the lower part of the layer 51, a signal is sent to the operation control device 15 so as to increase the flow rate of the fluidized gas. In the state where excess unburned carbon is retained in the lower part of the fluidized bed 51, there is a possibility that the fluidized gas will not be fluidized even if the fluidized gas is supplied to the fluidized bed 51. May send a signal to the operation control device 15 to stop the operation of the fluidized bed furnace 1.

The segment S in which the monitoring unit 93 monitors the unburned carbon ratio may be singular or plural. Further, as the segment S, the entire height direction of the flow layer 51 may be defined as one segment S, or a plurality of segments S continuous in the height direction of the flow layer 51 may be defined, or the flow layer may be defined. A plurality of segments S dispersed in the height direction of 51 may be defined. When a plurality of segments S are defined in the fluidized bed 51, the monitoring unit 93 monitors the unburned carbon ratio of the fluidized bed furnace 1 in operation, and the monitoring unit 93 does not have two or more segments S having different height levels. It is advisable to estimate the state of the fluidized bed 11 by comparing the fuel carbon ratio.

For example, the monitoring unit 93 can compare the unburned carbon proportions of two or more segments S and detect a local increase in the unburned carbon proportions in the fluidized bed 51. As described above, when the local increase in the unburned carbon ratio in the fluidized bed 51 is found, the monitoring unit 93 performs the treatment according to the portion where the unburned carbon ratio in the fluidized bed 51 is increased. For example, when the segment S in which the local increase in the unburned carbon ratio is found is the surface layer of the fluidized bed 51 or a portion close to the surface layer, the fuel is charged at the timing when the segment S rises to the surface layer of the fluidized bed 51. A signal is sent to the operation control device 15 so as to reduce the input amount. For example, when the segment S in which the local increase in the unburned carbon ratio is found is the bottom or a portion near the bottom of the fluidized bed 51, the monitoring unit 93 sets the timing at which the flow failure of the fluidized bed 51 is predicted. At the same time, a signal is sent to the operation control device 15 so as to increase the flow rate of the fluidized gas.

For example, the monitoring unit 93 can compare the unburned carbon proportions of the two or more segments S and detect an increase in the unburned carbon proportions over the entire height direction of the fluidized bed 51. Here, it is preferable that the two or more segments S are dispersed in the height direction of the fluidized bed 51 or continuous in the height direction of the fluidized bed 51. In this way, when an increase in the overall unburned carbon ratio in the fluidized bed 51 is found, the monitoring unit 93 reduces the fuel input amount, increases the flow rate of the fluidized gas, increases the fluidized medium, and the fluidized bed furnace. A signal is sent to the operation control device 15 so as to perform at least one process in the corresponding process group of the operation stop of 1.

In the above, the monitoring unit 93 instructs the operation control device 15 to take measures to be taken by the operation control device 15, but the monitoring unit 93 only performs a process of transmitting the estimated state of the fluidized bed 51 to the operation control device 15. May be done. In this case, the operation control device 15 performs processing corresponding to the estimated state of the fluidized bed 51 acquired from the monitoring unit 93.

As described above, the fluidized bed monitoring device 9 according to the present embodiment has a fluidized bed 51 in which a fluidized bed 51 formed by flowing a fluidized medium filled in the lower part of the furnace with a fluidized gas blown out from the bottom of the furnace. In the fluidized bed 1, the state of the fluidized bed 51 is monitored, and a segment S in the height direction is defined in the fluidized bed 51, and is provided on the inner wall of the fluidized bed furnace 1 in contact with the fluidized bed 51. The pressure sensor 91 that detects the pressure difference between the upper end level and the lower end level of the segment S, the calculation unit 92 that calculates the unburned carbon ratio of the segment S based on the detected pressure difference, and the fluidized bed furnace 1 are in operation. Is provided with a monitoring unit 93 for monitoring the unburned carbon ratio of the fluidized bed 51. The fluidized bed 51 can be read as a fluidized bed.

Here, in the calculation unit 92, for example, the difference between the pressure difference reference value, which is the pressure difference between the upper end level and the lower end level of the segment S in the state where fuel is not supplied to the fluidized bed 51, and the detected pressure difference. From, the unburned carbon ratio can be obtained.

Similarly, in the fluidized bed monitoring method according to the present embodiment, a segment S in the height direction is defined in the fluidized bed 51, a pressure difference between the upper end level and the lower end level of the segment S is detected, and the detected pressure is detected. Based on the difference, the unburned carbon ratio of the segment S is obtained, and the unburned carbon ratio of the fluidized bed 51 is monitored during the operation of the fluidized bed furnace 1.

According to the fluidized bed monitoring device 9 and the fluidized bed monitoring method described above, the proportion of unburned carbon such as unburned char in the fluidized bed 51 can be monitored during the operation of the fluidized bed furnace 1. Then, based on the change in the ratio of unburned carbon in the fluidized bed 51, it is possible to predict the deterioration of the flow characteristics of the fluidized bed 51 due to the increase in the ratio of unburned carbon in the fluidized bed 51. As a result, it is possible to perform an appropriate treatment before the flow characteristics of the fluidized bed 51 deteriorate, and it is possible to avoid deterioration of the flow characteristics of the fluidized bed 51.

Further, the monitoring unit 93 of the fluidized bed monitoring device 9 according to the present embodiment is configured to monitor the unburned carbon ratio of the fluidized bed 51 illustrated below. However, the monitoring unit 93 may be configured to perform at least one of those monitoring methods.
(1) When the unburned carbon ratio exceeds a predetermined threshold value in the segment S included in the range from the surface layer of the fluidized bed 51 to 1/3 of the height dimension of the fluidized bed 51, a predetermined process is performed. (2) When the unburned carbon ratio exceeds a predetermined threshold value in the segment S included in the range of 1/3 of the height dimension of the fluidized bed 51 from the bottom of the fluidized bed 51, a predetermined process is performed.
(3) When a local increase in the unburned carbon ratio in the fluidized bed 51 is found from the unburned carbon ratio in the two or more segments S, a predetermined treatment is performed.
(4) When an increase in the overall unburned carbon ratio of the fluidized bed 51 is found from the unburned carbon ratio of the two or more segments S, a predetermined treatment is performed.

By monitoring the unburned carbon ratio of the fluidized bed 51 by the above-mentioned method for monitoring the unburned carbon ratio, the flow characteristics of the fluidized bed 51 are improved due to the increase in the ratio of unburned carbon in the fluidized bed 51. You can predict it before it gets worse. Then, by performing an appropriate treatment before the flow characteristics of the fluidized bed 51 deteriorate, it is possible to avoid deterioration of the flow characteristics of the fluidized bed 51.

Although the preferred embodiment of the present invention has been described above, the present invention may include modified details of the specific structure and / or function of the above embodiment without departing from the spirit of the present invention. ..

For example, the fluidized bed portion 11 of the fluidized bed furnace 1 according to the above embodiment is an internal circulating fluidized bed, but the fluidized bed monitoring device 9 and the fluidized bed monitoring device 9 according to the present invention can also be used in other modes such as an external circulating fluidized bed. Methods can be applied to detect and monitor the percentage of unburned carbon in fluidized beds.

Further, in the above embodiment, the case where the flow inhibitor that reduces the fluidity of the fluidized bed 51 by reducing the density of the fluidized bed 51 is unburned carbon has been described, but the flow inhibitor is limited to unburned carbon. Not done.

For example, in a fluidized bed furnace using a mixture of a plurality of materials including an oxygen occlusion / release material such as ilmenite (Fe-based) and a carbon gasification promoting material such as Ni ore as a fluidized bed, the fluid is fluidized as a fluidized bed factor. The proportion of gasification-promoting material in the layer 51 may be monitored. In this case, in the above embodiment, by replacing the unburned carbon with "gasification promoting material", the ratio of the gasification promoting material in the fluidized bed 51 is monitored, and the flow characteristics of the ratio of the gasification promoting material are deteriorated. Can be predicted.

Further, for example, as a fluidized bed, a fluidized bed furnace using a mixture of a plurality of materials including silica sand and an anti-aggregation agent composed of a material (porous substance such as zeolite or calcium oxide) that absorbs an alkaline component of the silica sand. Then, the ratio of the antiaggregating agent in the fluidized bed 51 may be monitored as a fluidizing inhibitor. In this case, in the above embodiment, by replacing the unburned carbon with "anti-aggregation agent", the ratio of the anti-aggregation agent in the fluidized bed 51 is monitored, and the deterioration of the flow characteristics of the ratio of the anti-aggregation agent is predicted. be able to.

1: Fluidized bed furnace 3: Combustion exhaust gas system 4: Exhaust gas recirculation system 10: Furnace body 10a: First side wall 10b: Second side wall 11: Fluidized bed part 12: Free board part 13: Squeezing part 15: Operation control device 31 : Heat exchange device 32: Cyclone type dust collector 33: Bug filter 34: Attracting blower 40: Gas recirculation blower 41: First partition wall 42: Second partition wall 43: Ceiling wall 51: Fluidized bed 52: Gas supply device for fluidization 53: Combustion area 54: Heat recovery area 55, 56, 57: Communication port 61: Combustion cell 62: Circulation cell 63: Heat collection cell 64: Heat transfer tube 65: Fuel input port 68: Unburned gas supply port 69: Tertiary combustion Gas supply port 70: Temperature sensor 72: Extraction outlet 79: Pushing blower 80: Air diffuser pipe 81, 82, 83: Flow gas supply pipe 81a, 82a, 83a: Flow adjustment means 81b, 82b, 83b: Flow meter 88, 89: Flow adjustment means 9 Fluid bed monitoring device 91: Pressure sensor 92: Calculation unit 93: Monitoring unit 100: Combustion system

Claims (10)

A fluidized bed monitoring method for monitoring the state of the fluidized bed in a fluidized bed furnace in which a fluidized bed formed by flowing a fluidized medium filled in the lower part of the furnace with a fluidized gas blown from the bottom of the furnace.
A segment in the height direction is defined in the fluidized bed, and the pressure difference between the upper end level and the lower end level of the segment is detected.
Based on the detected pressure difference, the proportion of the flow inhibitor contained in the segment, which reduces the fluidity of the fluidized bed by reducing the density of the fluidized bed, was determined.
Monitor the proportion of the fluidized bed factor during the operation of the fluidized bed furnace,
Fluidized bed monitoring method. The ratio of the fluidized bed is determined from the difference between the detected pressure difference and the pressure difference reference value, which is the pressure difference between the upper end level and the lower end level of the segment in a state where fuel is not supplied to the fluidized bed. Ask,
The fluidized bed monitoring method according to claim 1. The proportion of the flow inhibitor was determined in two or more of the segments having different height levels.
Monitor the proportion of the fluidized bed factor in two or more of the segments during the operation of the fluidized bed furnace.
The fluidized bed monitoring method according to claim 1 or 2. When a local increase in the proportion of the flow-inhibiting factor in the fluidized bed is found from the proportion of the flow-inhibiting factor in two or more of the segments, a predetermined treatment is performed.
The fluidized bed monitoring method according to claim 3. When an increase in the overall proportion of the fluidized bed in the fluidized bed is found from the proportion of the fluidized bed in the two or more segments, a predetermined treatment is performed.
The fluidized bed monitoring method according to claim 3. A fluidized bed monitoring device for monitoring the state of the fluidized bed in a fluidized bed furnace in which a fluidized bed formed by flowing a fluidized medium filled in the lower part of the furnace with a fluidized gas blown from the bottom of the furnace is formed.
A segment in the height direction is defined in the fluidized bed.
A pressure sensor provided on the inner wall of the fluidized bed furnace in contact with the fluidized bed to detect the pressure difference between the upper end level and the lower end level of the segment.
Based on the detected pressure difference, a calculation unit for obtaining the ratio of a flow inhibitor containing in the segment to reduce the fluidity of the fluidized bed by reducing the density of the fluidized bed, and
A monitoring unit for monitoring the ratio of the fluidized bed factor during the operation of the fluidized bed furnace is provided.
Fluidized bed monitoring device. The flow unit is based on the difference between the detected pressure difference and the pressure difference reference value, which is the pressure difference between the upper end level and the lower end level of the segment in a state where fuel is not supplied to the fluidized bed. Find the percentage of inhibitor,
The fluidized bed monitoring device according to claim 6. The calculation unit obtains the ratio of the flow inhibitor in two or more of the segments having different height levels.
The monitoring unit monitors the proportion of the fluidized bed factor in two or more of the segments during the operation of the fluidized bed furnace.
The fluidized bed monitoring device according to claim 6 or 7. When the monitoring unit finds a local increase in the ratio of the flow-inhibiting factor in the fluidized bed from the ratio of the flow-inhibiting factor in two or more of the segments, a predetermined process is performed.
The fluidized bed monitoring device according to claim 8. When the monitoring unit finds an increase in the overall proportion of the fluidized bed in the fluidized bed from the proportion of the fluidized bed in the two or more segments, it performs a predetermined treatment.
The fluidized bed monitoring device according to claim 8.

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