JPS5841320B2 - Colloidal fuel production equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel colloidal fuel manufacturing device, and particularly to a device for manufacturing colloidal fuel by mixing and pulverizing coal and heavy oil. In addition to lowering the heating temperature, the exhaust gas emitted during the mixing and pulverization of heavy oil and coal is combusted, and the resulting combustion waste gas is used as drying gas to dry the coal. The present invention relates to a colloidal fuel manufacturing apparatus that can lower the temperature and effectively treat purging exhaust gas exhausted during mixing.

Generally, a technique is known in which colloidal fuel is produced by mixing coal and heavy oil and pulverizing the coal.

By the way, in a conventional colloidal fuel production device, there is a mill section for pulverizing coal while mixing coal and heavy oil;
It mainly consists of a separator that separates and removes oil mist from the exhaust gas purged inside the mill section.

On the other hand, coal is constantly sprinkled with water and stored in a highly moist state to prevent ignition or spontaneous combustion, or to prevent coal dust from scattering.

In addition, in coal storage yards, coal is stored in a highly moist state due to rainwater.

Therefore, in the mill section of the conventional apparatus, the coal supplied or charged during mixing with heavy oil is heated to evaporate the water content.

Specifically, heavy oil was heated above its flash point, and coal was heated with this high-temperature heavy oil.

Generally, coal containing high moisture content is fed into the mill at room temperature, and then high-temperature heavy oil is added to it and mixed and pulverized, and the colloidal fuel that is a mixture of coal and heavy oil has a high viscosity. Therefore, a high manufacturing temperature of 90 to 100°C is maintained.

In particular, in order to evaporate the moisture contained in coal, 1 liter of heavy oil is added.
It is necessary to heat it to 80°C to 250°C.

Therefore, volatile gas is generated in the mill due to thermal decomposition during the mixing and pulverizing process of coal and heavy oil, which can cause an explosion.

To prevent explosions within the mill, air is sucked into the mill and exhausted to purge the volatile gas (raw gas) generated.

When the inside of the mill reaches a high temperature, a large amount of volatile gas is generated, necessitating powerful purging.

In addition, coal dust is also generated within the mill section, so it is necessary to discharge this to the outside.

Therefore, the purge exhaust gas exhausted from the mill section contains oil mist and coal dust, and a separator is provided to remove these.

This separator had a problem in that it was not possible to completely remove oil mist and the like in the purging exhaust gas and that it could not be discharged outside the system.

Therefore, the present invention has been devised to effectively solve the problems of conventional colloidal fuel production apparatuses.

An object of the present invention is to provide a colloidal fuel manufacturing apparatus that can minimize the generation of volatile gas during the mixing and pulverizing process of coal and heavy oil, and can prevent explosion accidents in the mill section.

Another object of the present invention is to make it possible to recover heat by burning the remaining oil mist and exhaust gas containing coal dust after removing oil mist from purging exhaust gas, and to dry coal with the combustion waste gas. Provided is a colloidal fuel production device that can achieve effective use of waste gas.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a coal dryer, specifically a rotary dryer or an air flow/fluidized bed type dryer.

A wet mill section 4 is provided at the discharge port 2 of the coal dryer 1 via a dry coal transfer passage or transfer system 3 for transferring dried coal.

The mill section 4 is connected to the passage 3 for charging coal.

Further, the mill section 4 is provided with a charging port so that coal can be charged through a buffer bin or the like.

The mill section 4 also includes a heavy oil supply system 5 for supplying heavy oil.
is connected to this heavy oil supply system 5, and a heavy oil heater 6 is connected to this heavy oil supply system 5.
is interposed.

This heavy oil heater 6 heats heavy oil transferred from a heavy oil supply tank 8 using steam from a steam boiler 7, which will be described later.
It is configured to be supplied to the mill section 4.

The mill section 4 is provided with a purge air supply system 9, and is configured to constantly supply purge air inside.

Further, the mill section 4 is provided with a colloidal fuel outlet 10 in which coal and heavy oil are mixed and the coal is appropriately pulverized into particles.

The mill section 4 is also provided with a purging exhaust gas system 11, and this purging exhaust gas system 11 is provided with a separator 12, which is configured to remove oil mist and the like contained in the exhaust gas. ing.

A combustion engine 14 is connected to the exhaust system 13 of the separator 12 .

This combustion engine 14 is specifically a steam boiler 7, which burns residual mist contained in the purge exhaust gas exhausted from the separator 12.

Since the purge exhaust gas contains residual mist, it becomes not only combustible gas as fuel but also combustion air.

The steam boiler 7 is separately provided with a fuel supply system 15, which is configured so that the purging exhaust gas and the supplied fuel can be mixed and combusted.

The steam obtained from the steam boiler 7 is transferred to the aforementioned heavy oil heater 6 to heat the heavy oil and is also used for factory utilities.

The exhaust system 16 of the combustion engine 14 is connected to the coal dryer 1 and is configured so that high-temperature waste gas obtained from the combustion engine 14 can be used as drying gas for the coal dryer 1.

Further, the exhaust system 13 of the separator 12 is branched and a hot air stove 17 is provided.

This hot air stove 17 uses the exhaust gas from the separator 12 as combustion air, is for absorbing load fluctuations of the steam boiler 7, and is for heating dry gas, which is the waste gas from the exhaust system 16.

A dust collector 1 is provided in the dry gas exhaust system 18 of the coal dryer 1.
9 and a flue gas treatment device 20 are provided.

The solid matter discharge system 21 of the dust collector 19 is connected to the dry coal transfer system 3 that connects the coal dryer 1 and the mill section 4,
It is configured to supply the coal dust collected by the dust collector 19 to the mill section 4 together with the coal.

The operation of this device having the above configuration will be described in detail below.

First, coal containing a large amount of moisture, which has been sprinkled with rainwater, dust, and water to prevent spontaneous combustion in a coal storage yard, is crushed in advance using a crusher, etc., and fed into the coal dryer 1 by the coal supply system 22, where it is discharged as waste gas. It will be heated with drying gas.

The dried coal is supplied to the mill section 4 via the dry coal transfer system 3, and mixed with heavy oil heated by the heavy oil heater 6, while the coal is appropriately pulverized into particles to produce colloidal fuel.

In particular, since the coal is sufficiently dried in the dryer 1 and contains almost no water, there is no need to heat it in the mill section 4 with heavy oil to evaporate the water.

Therefore, the temperature of the heavy oil can be set to about 100°C, which is necessary for coal to mix with the heavy oil and become colloidal, and volatile gases generated from the heavy oil can be suppressed to a minimum and the inside of the mill section 4 can be kept at a low temperature. can be maintained and explosion accidents can be prevented.

Air is constantly introduced into the mill section 4 from a purge air supply system 9 in order to purge volatile gas and dust (coal dust).
It is transferred from the purging exhaust gas system 11 to the separator 12.

The exhaust gas taken out from the exhaust gas system 11 contains oil mist and the like, and these mist are separated and removed by the separator 12 and taken out of the system as collected mist.

The exhaust gas exhausted from the separator 12 contains residual mist, which is transferred as combustible gas or combustion air to the steam boiler 7 as the combustion engine 14, where it is combusted together with fuel.

Steam obtained from the steam boiler 7 is supplied to the heavy oil heater 6 to heat the heavy oil.

The exhaust gas from the separator 12 combusted in the steam boiler γ becomes waste gas and is transferred to the dryer 1 via the exhaust system 16.

The waste gas transferred by this exhaust system 16 becomes dry gas for the dryer 1.

In particular, since the waste gas becomes dry gas, it is necessary to prevent coal dust explosion inside the coal dryer 1, so the inlet oxygen temperature is 10%.
The fuel consumption of the steam boiler 7 as the combustion engine 14 and the hot blast furnace 17 to be described later is controlled so that the inlet temperature is below the coal dust explosion limit temperature corresponding to the inlet oxygen concentration.

The hot air stove 17 absorbs the load fluctuation of the steam boiler 7 and secondarily maintains the dry gas at a predetermined temperature and oxygen concentration. 17 becomes unnecessary.

The waste gas thus obtained from the combustion engine 14 is transferred to the coal dryer 1 to dry the coal, and then exhausted through the dry gas exhaust system 18.

A dust collector 19 is provided in the dry gas exhaust system 18 of the dryer 1. Since the gas exhausted from the dryer 1 contains a large amount of coal dust, the dust collector 19 removes the coal dust. is collected and supplied into the mill section 4 via the solid matter discharge system 21.

The dust collector 19 may be a cyclone, a bag filter, or the like.

The gas leaving the dust collector 19 passes through the flue gas treatment device 20 and is discharged from the leveling rod 23 to the atmosphere.

In summary, the present invention exhibits the following excellent effects.

(1) A coal dryer is installed just before the wet mill section where coal and heavy oil are mixed, and the coal can be dried in advance to remove moisture, reducing the amount of dry moisture and reducing the sensible heat of the coal. Due to this increase, the heat load within the mill section can be reduced, and the heating temperature of heavy oil can be reduced.

(2) Since the heating temperature of the heavy oil is lowered, the amount of volatile matter due to thermal decomposition etc. is reduced, making it possible to prevent explosions within the mill.

(3) The purge exhaust gas that has purged the mill section is burned by the combustion engine, heat is recovered, and it can be effectively used as drying gas for the dryer, which is extremely effective in terms of energy conservation.

(4) Coal dust explosion within the dryer can be prevented by controlling the oxygen concentration and temperature of the drying gas at the inlet of the dryer.

(5) Since the coal is not dried in oil in the wet mill section but is dried with drying gas, the coal drying surface area can be increased and the drying rate can be increased.

[Brief explanation of the drawing]

The figure is a schematic system diagram showing a preferred embodiment of the present invention. In the figure, 1 is a coal dryer, 4 is a mill section, 12 is a separator, 1
4 is a drying engine, 7 is a steam boiler, 6 is a heavy oil heater, 17
is a hot stove.

Claims (1)

[Claims] 1. A mill section that adds heavy oil to coal and mixes and pulverizes it to produce a colloidal fuel that is a mixture of coal and heavy oil; a separator that removes oil mist in the purging exhaust gas exhausted from the mill section; A combustion engine that uses the exhaust gas after oil mist removal obtained from the separator as combustion air, and a coal that uses the combustion waste gas exhausted from the combustion engine as dry gas and is installed on the coal supply side of the mill section to dry the supplied coal. A colloidal fuel production device characterized by comprising a dryer.