JP3962308B2 - Treatment method of biomass in coke dry fire extinguishing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a biomass processing method in which biomass such as wood and sewage sludge cake is processed and effectively used in a coke dry fire extinguishing facility.
[0002]
[Prior art]
As a method for treating biomass in a coke dry fire extinguishing facility, for example, Patent Literature 1 discloses a method in which biomass (sewage sludge cake) is charged into a pre-chamber of a cooling tower of a coke dry fire extinguishing facility and pyrolyzed.
[0003]
The thermal decomposition method disclosed in Patent Document 1 uses the sensible heat of red hot coke to thermally decompose the organic components of the sewage sludge cake in the pre-chamber, and the water in the sewage sludge cake and red hot coke are aqueous. A gasification reaction is performed and the gas is introduced into a flue as a combustible gas such as CO or H ₂ , and combustion air is introduced into the flue and burned.
[0004]
In the flue of the coke dry fire extinguishing equipment, a gravity settling solid-gas separation mechanism called a dust catcher is provided to protect the boiler. The gravity-settling solid-gas separation mechanism uses the inertial force of solids to settle, and if the gas flow is turbulent, the inertial force of the solids is hindered and the solid-gas separation efficiency is significantly reduced. In the fire extinguisher flue, the gas flow rate is reduced as much as possible to keep the gas in a laminar state. Therefore, it is very difficult to mix and burn the combustible gas and the combustion air in the flue while maintaining the solid-gas separation performance, and the residence time is short, so the amount of combustion is limited. Further, if the combustible gas remains without being combusted completely, a corrosive component such as H ₂ S is generated, and the metal is corroded at the bottom of the boiler and the cooling tower to cause a large facility trouble.
[0005]
Carbon such as fixed carbon is present in biomass such as wood and sewage sludge cake. Fixed carbon is the carbon content that remains as solid carbon without being gasified when the raw material is pyrolyzed in an oxygen-free atmosphere. Ordinary biomass contains about 20% by weight of fixed carbon. When the biomass raw material is pyrolyzed in the pre-chamber of the coke dry fire extinguishing equipment, the fixed carbon content in the biomass is guided to the flue along with the combustible gas as dust. As described above, since the combustion efficiency is poor in the flue, the scattered dust (fixed carbon) is collected by the dust catcher without burning, and the calorific value due to the combustion of the fixed carbon has not been effectively utilized. The calorific value of the fixed carbon is very high because it is all carbon, accounting for about 40% of the calorific value of biomass.
[0006]
[Patent Document 1]
Japanese Patent No. 2789988 [0007]
[Problems to be solved by the invention]
The problem to be solved by the present invention is that a large amount of biomass can be effectively used without causing trouble of corrosion of equipment due to residual flammable gas, and the fixed carbon of the charged biomass can be recovered as dust. Another object of the present invention is to provide a method for treating biomass in a coke dry fire extinguishing facility that can be recovered and used effectively as heat.
[0008]
[Means for Solving the Problems]
The method for treating biomass in the coke dry fire extinguishing system of the present invention is a coke dry type in which red hot coke is charged into the pre-chamber from the coke charging inlet at the upper part of the cooling tower, and inert gas is introduced from the lower part of the cooling tower to cool the red hot coke. When processing biomass such as wood and sewage sludge cake in the fire extinguishing equipment, the biomass is charged into the pre-chamber from one or more biomass inlets provided in the pre-chamber above the coke dry fire extinguishing equipment. The biomass is thermally decomposed into combustible gas and biomass pulverized fixed carbon in the pre-chamber, and combustion air in an amount of air necessary for complete combustion of the charged biomass is blown into the pre-chamber.
[0009]
In the present invention, the combustion air for burning the exhaust gas after burning the biomass powdered fixed carbon and combustible gas after pyrolysis again seen write blown into the annular duct and / or flue, unburned gas may be prevented from occurring, so that blowing of water and / or steam to control the temperature of the pre-chamber increases due to the combustion of the biomass powdering fixed carbon and combustible gas after the pyrolysis in said pre-chamber Anyway.
[0011]
Further, in the present invention, the biomass can be charged into the pre-chamber from two or more biomass inlets, and the cutting and dispersing device provided with rotating blades provided with the biomass in the vicinity of the biomass inlets, or Alternatively, the pre-chamber can be distributed and loaded by a chute having a changeable inclination angle and / or direction.
[0012]
In the present invention, the charging of the biomass into the pre-chamber is stopped or charged in order to prevent gas leakage from the coke charging inlet during the period when the lid of the coke charging inlet is opened due to red hot coke charging into the pre-chamber. The amount of input can be reduced.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples shown in the drawings.
[0014]
Example 1
FIG. 1 is a configuration diagram of a coke dry fire extinguishing facility for carrying out the biomass processing method of the present invention. In the coke dry fire extinguishing equipment, the red hot coke 1 is supplied from the coke charging inlet 3 at the upper part of the cooling tower 2, and then is introduced into the pre-chamber 4 after the lid 3 a is opened and lowered and supplied from the cooling gas pipe 14 at the lower part of the cooling tower 2. The inert gas as the cooling gas is heat exchanged with the red hot coke 1, and the high temperature inert gas recovered from the heat of the red hot coke 1 is introduced into the boiler 13 from the annular duct 5 through the flue 10 and heat exchanged. After that, the circulation blower 15 is circulated by being pumped to the lower part of the cooling tower 2. The cooled coke is discharged from the coke discharge port 6 at the bottom of the cooling tower 2.
[0015]
The pre-chamber 4 is provided with a biomass inlet 7 such as wood and sewage sludge cake and a combustion air inlet 8. Of the biomass, wood is roughly crushed to about 10 to 50 mm with a hammer crusher or the like (not shown) and is continuously charged from the biomass charging port 7. The flue 10 is provided with a combustion air inlet 9, a collision wall 11, and a dust catcher 12 for collecting dust separated by the collision wall 11. Further, a cyclone 16 for separating dust is provided in a pipe between the boiler 13 and the circulation blower 15.
[0016]
In this coke dry fire extinguishing equipment, biomass is processed as follows.
[0017]
Biomass charged into the pre-chamber 4 from the biomass inlet 7 is thermally decomposed into combustible gas and biomass fixed carbon by the sensible heat of the red hot coke 1. The combustible gas generated by the pyrolysis is combusted in the pre-chamber 4 by the combustion air continuously introduced from the combustion air inlet 8. As the combustion air, an air amount necessary for complete combustion of the charged biomass (hereinafter referred to as “necessary air amount”) is introduced. Similarly, biomass-fixed carbon produced by pyrolysis is combusted with combustion air. Biomass-fixed carbon is pulverized in a packed bed of red hot coke 1 because its strength is significantly lower than that of coke. The pulverized biomass-fixed carbon has a remarkably large specific surface area compared to the red hot coke 1 and is made porous by thermal decomposition, so that the combustibility is very good. As a result, the red hot coke 1 is preferentially burned before burning. In addition, the residence time in the pre-chamber 4 is much longer than the residence time in the flue 10, and the gas is in a turbulent state due to the packed bed of the red hot coke 1, so that it is reliably mixed and burned. Done efficiently.
[0018]
The exhaust gas that has finished burning contains a small amount of combustible components due to the equilibrium reaction due to its moisture, and is led to the flue 10 via the annular duct 5. In the flue 10, combustion air is continuously introduced again from the combustion air inlet 9. Since the combustible amount is small, it burns completely even in a short residence time, and is completely burned until the exhaust gas reaches the collision wall 11 installed in the flue 10, and unburned biomass fixed carbon collides. There is no collision with the wall 11. Thus, all the fixed carbon in the biomass raw material is burned and converted into exhaust gas sensible heat, and is effectively heat-exchanged and recovered by the boiler 13. As a result, a large amount of biomass is processed by the coke dry fire extinguishing equipment, and the total amount of heat possessed by the biomass can be recovered and used as heat.
[0019]
Here, the combustion air for recombusting the exhaust gas after burning the biomass-fixed carbon and the combustible gas after pyrolysis is introduced into the flue 10 as in the above embodiment, and the annular duct 5 It may be introduced inside or both.
[0020]
On the other hand, when the lid 3a is opened when red hot coke is charged, a large amount of air flows from the coke charging inlet 3 at the top of the cooling tower 2. Therefore, if the prechamber 4 is filled with combustible gas, there is a risk of explosion. Moreover, since 80% or more of biomass is volatile, a large amount of gas is released. When the total amount of the released gas amount and the air amount flowing in from the coke charging inlet 3 exceeds the allowable amount of the circulation blower 15, the top of the cooling tower 2 becomes a positive pressure and the gas leaks from the coke charging inlet 3. Therefore, when processing the biomass, while the cover 3a of the coke charging inlet 3 is opened, the charging of the biomass into the pre-chamber 4 is stopped or the charging amount is reduced. As a result, gas leakage and the like can be avoided without increasing the capacity of the circulation blower 15.
[0021]
Example 2
FIG. 2 is a block diagram of a coke dry fire extinguishing facility for implementing another embodiment of the present invention. In addition to the biomass charging inlet 7 and the combustion air inlet 8, the pre-chamber 4 of the coke dry fire extinguishing equipment of FIG. 2 is provided with an inlet 17 for water and / or steam.
[0022]
As described above, when a large amount of biomass is combusted in the pre-chamber 4 and effectively used, the temperature rises in the pre-chamber 4. This rise in temperature causes a serious problem of ash melting as well as the effect on the equipment. In general, the melting point of ash contained in biomass is lower than the melting point of coal ash. Therefore, when burning at high temperature, the ash is scattered in a semi-molten state and adheres to walls, heat transfer tubes, etc., causing harmful effects. Therefore, it is necessary to perform combustion temperature management. Therefore, for temperature control when a large amount of biomass is burned in the pre-chamber 4, water / steam is blown from the introduction port 17 as necessary to control the temperature. The blown water / steam generates a carbon gas and water gasification reaction (endothermic reaction) in the pre-chamber 4 to cool the pre-chamber 4. This temperature control makes it possible to make maximum use of biomass without melting ash, without generating unburned gas, and without exhausting the recoverable heat as dust to the outside of the system. Become.
[0023]
Reference example 1
FIG. 3 is a configuration diagram of a coke dry fire extinguishing facility that implements part of the biomass processing method of the present invention. In the coke dry fire extinguishing system of FIG. 3, the pre-chamber 4 is not provided with the combustion air inlet 18 for introducing the combustion air for burning the pyrolyzed biomass fixed carbon and the combustible gas, but the annular duct 5 And provided in the flue 10.
[0024]
As described above, it is difficult to completely burn the biomass-fixed carbon generated by the pyrolysis of the biomass because the residence time is too short simply by introducing the combustion air into the flue 10. . Therefore, in this embodiment, combustion air is introduced into the annular duct 5 and the time for burning the biomass-fixed carbon with the combustion air is lengthened. In that sense, it is preferable to introduce the entire required amount of air from the annular duct 5, but when a large amount of combustion air is introduced into the annular duct 5, the temperature of the annular duct 5 significantly increases due to the combustion heat, As described above, the temperature rise in the annular duct 5 causes melting and adhesion of biomass ash. In general, since the inner wall of the annular duct 5 has a brick unit structure and does not have high-temperature strength, it is necessary to avoid a local high temperature, and the temperature of the inner wall of the annular duct 5 needs to be maintained below an allowable temperature. Therefore, in this embodiment, the gas temperature in the annular duct 5 is measured by a temperature sensor (not shown), and combustion from the annular duct 5 is performed so that the gas temperature does not exceed an allowable temperature (for example, 1000 ° C.). The amount of necessary air blown is controlled so that the remaining amount of the required air is blown into the flue 10.
[0025]
This combustion air blowing method makes it possible to prevent a small amount of coke combustion when air is introduced into the pre-chamber 4, without causing loss of coke as a product and without melting ash. Further, it is possible to make maximum use of biomass without generating unburned gas and without discharging the recoverable amount of heat as dust to the outside of the system.
[0026]
Reference example 2
FIG. 4 is a configuration diagram of a coke dry fire extinguishing facility that implements a part of the biomass processing method of the present invention.
[0027]
As the biomass throughput increases, the heat transfer efficiency decreases and the temperature of the biomass does not increase, so that pyrolysis and combustion are not reliably performed, and a portion where the thermal efficiency decreases occurs. And the part becomes low temperature, and if that part exists in the inner wall vicinity of the cooling tower 2, it will have a bad influence also on the brick which comprises an inner wall. One factor that reduces the heat transfer efficiency is the filling thickness of the biomass. That is, when a locally thick portion exists in the filling thickness, the temperature is lowered due to the heat insulating effect of the biomass, and the thermal efficiency of the portion is lowered.
[0028]
Therefore, in order to increase the throughput of biomass without reducing the thermal efficiency, it is necessary to charge the biomass evenly into the prechamber 4. For this reason, the coke dry fire extinguishing equipment of FIG. 4 is provided with two or more biomass inlets 7 to disperse the biomass in the pre-chamber 4 so that it can be charged as evenly as possible.
[0029]
Further, as shown in FIG. 5, if a cutting and dispersing device 19 having a rotary blade is provided in the vicinity of the biomass charging port 7, the biomass can be charged more evenly into the prechamber 4.
[0030]
In addition, as shown in FIG. 6, the biomass can be more evenly distributed in the prechamber 4 by providing a biomass charging chute 20 whose inclination angle and / or direction can be changed in the vicinity of the biomass charging inlet 7. Can be charged [0031]
【The invention's effect】
In the method for treating biomass in the coke dry fire extinguishing equipment of the present invention, combustion air for burning the biomass-fixed carbon and the combustible gas after pyrolysis is blown into the pre-chamber, so that most of the unburned gas is pre-chamber. Burned in. Therefore, a large amount of biomass can be effectively used without causing the corrosion trouble of the equipment due to the remaining of the combustible gas. Further, since the biomass fixed carbon is also preferentially burned in the pre-chamber by the combustion air, it can be recovered and used as heat without recovering the fixed carbon of the charged biomass as dust.
[0032]
In addition, by blowing combustion air into the annular duct and / or the flue, it becomes possible to completely burn the biomass-fixed carbon, and the total amount of heat possessed by the biomass can be recovered and used as heat. It becomes possible. Further, by blowing water and / or steam for temperature control into the pre-chamber, it is possible to suppress the temperature rise in the pre-chamber without causing adverse effects such as adhesion due to melting of ash in biomass having a low melting point. A large amount of biomass can be processed, and the amount of heat possessed by the biomass can be recovered and used as heat.
[0034]
In addition, the biomass can be charged into the bleed chamber from two or more inlets, a cutting and dispersing device provided with rotating blades in the vicinity of the biomass inlet, an inclination angle and / or in the vicinity of the biomass inlet By providing a chute for biomass charging, the direction of which can be changed, the biomass can be dispersed in the pre-chamber and charged evenly, preventing a decrease in temperature due to the heat insulation effect of the biomass, and a refractory due to temperature fluctuations It is possible to process a large amount of biomass without causing adverse effects on the environment and without lowering the thermal efficiency due to insufficient thermal decomposition and combustion of the biomass, and recovering and effectively using the entire amount of heat possessed by the biomass as heat. It becomes possible to do.
[0035]
Further, it is possible to avoid gas leakage by stopping the charging of biomass into the pre-chamber or reducing the charging amount when the lid is opened, such as when charging red hot coke.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a configuration diagram of a coke dry fire extinguishing facility for implementing a biomass processing method of the present invention.
FIG. 2 is a configuration diagram of a coke dry-type fire extinguishing facility for implementing another embodiment of the present invention.
FIG. 3 is a configuration diagram of a coke dry fire extinguishing facility for carrying out part of the biomass processing method of the present invention.
FIG. 4 is a configuration diagram of a coke dry fire extinguishing facility for carrying out part of the biomass processing method of the present invention.
FIG. 5 is a view showing a cutting and dispersing device provided in the vicinity of a biomass charging port.
FIG. 6 is a view showing a biomass charging chute provided in the vicinity of a biomass charging inlet.

Claims (6)

Biomass such as wood and sewage sludge cake is treated in a coke dry fire extinguishing system that charges red hot coke into the pre-chamber from the coke inlet at the top of the cooling tower and introduces inert gas from the bottom of the cooling tower to cool the red hot coke. In doing so, biomass is charged into the pre-chamber from one or more biomass inlets provided in the pre-chamber above the coke dry fire extinguishing equipment, and this biomass is combusted gas and biomass pulverized in the pre-chamber. A method for treating biomass in a coke dry fire extinguishing system, characterized in that combustion air is blown into a pre-chamber with an amount of air necessary for complete combustion of the biomass that has been pyrolyzed into fixed carbon.   To prevent the generation of unburned gas by blowing combustion air into the annular duct and / or flue for recombusting the exhaust gas after burning pyrolyzed biomass powdered fixed carbon and combustible gas The processing method of the biomass in the coke dry fire extinguishing equipment of Claim 1 characterized by the above-mentioned.   The water and / or steam for controlling the temperature in the pre-chamber which rises by combustion of the biomass powdered fixed carbon and the combustible gas after pyrolysis is blown into the pre-chamber. A method for treating biomass in the described coke dry fire extinguishing equipment.   The coke dry type according to any one of claims 1 to 3, wherein the biomass is dispersed and charged into the pre-chamber by a cutting and dispersing device provided with a rotary blade provided in the vicinity of the biomass charging inlet. Biomass processing method in fire extinguishing equipment.   4. The biomass is distributedly charged into the pre-chamber by a chute provided in the vicinity of the biomass charging inlet and having a changeable inclination angle and / or direction. Biomass treatment method in coke dry fire extinguishing equipment.   In order to prevent gas leakage from the coke charging inlet during the open period of the coke charging inlet due to red hot coke charging into the pre-chamber, the charging of the biomass into the pre-chamber is stopped or the charging amount is reduced. The method for treating biomass in the coke dry fire extinguishing equipment according to any one of claims 1 to 3.

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