JP2004155800A - Method for treating biomass in coke dry quenching equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for treating biomass in coke dry quenching equipment effectively utilizing a large amount of the biomass without causing corrosion trouble to the equipment due to remaining of combustible gases, recovering fixed carbon of the charged biomass as heat without recovering the fixed carbon as dust and effectively utilizing the fixed carbon. <P>SOLUTION: The biomass such as wood or a sewage sludge cake is treated with the coke dry quenching equipment for charging red-hot coke 1 from a coke charging port 3 in the upper part of a cooling column 2 into a prechamber 4, introducing an inert gas from the lower part of the cooling column 2 and cooling the red-hot coke 1. In the process, the biomass is charged into the prechamber 4 and pyrolyzed into combustible gases and biomass-fixed carbon in the prechamber 4. Combustion air for burning the biomass-fixed carbon and combustible gas after the pyrolysis is blown into the prechamber 4, or blown into an annular duct 5 and a flue 10. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method for treating biomass, such as wood and sewage sludge cake, which is effectively used by treating biomass 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 Document 1 discloses a method in which biomass (sewage sludge cake) is charged into a prechamber of a cooling tower of a coke dry fire extinguishing facility and subjected to thermal decomposition treatment.
[0003]
The thermal decomposition treatment method disclosed in Patent Document 1 uses the sensible heat of red hot coke to thermally decompose organic components of sewage sludge cake in a pre-chamber, and converts water in the sewage sludge cake and red hot coke to an aqueous solution. by gasification reaction, CO, leads to the flue as a combustible gas such as H _2, is intended for introducing combustion air in the flue combustion.
[0004]
In the flue of the coke dry fire extinguishing system, a gravity sedimentation type solid-gas separation mechanism called a dust catcher is provided to protect the boiler. The gravity sedimentation-type solid-gas separation mechanism uses the inertia force of a solid to settle.If the gas flow is made turbulent, the inertia force of the solid is impeded and the efficiency of solid-gas separation is significantly reduced. In the fire extinguisher flue, the gas flow velocity is reduced as much as possible to keep the gas in a laminar flow state. Therefore, it is very difficult to mix and burn combustible gas and combustion air in the flue while maintaining solid-gas separation performance, and the residence time is short, so that the amount of combustion is limited. If the combustible gas does not completely burn and the combustible gas remains, corrosive components such as H ₂ S are generated, and the metal is corroded in the boiler, the lower part of the cooling tower, and the like, causing serious equipment trouble.
[0005]
Biomass such as wood and sewage sludge cake contains a carbon content called fixed carbon. The fixed carbon is a carbon content that is not gasified and remains as solid carbon when the raw material is thermally decomposed in an oxygen-free atmosphere. Normal biomass contains about 20% by weight of fixed carbon. When the biomass raw material is thermally decomposed in the pre-chamber of the coke dry fire extinguishing system, the fixed carbon content in the biomass is guided to the flue together with combustible gas as dust. As described above, since the flue has low combustion efficiency, the scattered dust (fixed carbon) is collected by the dust catcher without burning, and the calorific value generated by burning the fixed carbon has not been effectively used. The calorific value of the fixed carbon component is very high because all carbon is used, and accounts for about 40% of the calorific value of biomass.
[0006]
[Patent Document 1]
Japanese Patent No. 2789988
[Problems to be solved by the invention]
The problem to be solved by the present invention is that it is possible to effectively use a large amount of biomass without causing a corrosion problem of equipment due to residual combustible gas, and without collecting fixed carbon of the charged biomass as dust. It is an object of the present invention to provide a method for treating biomass in a coke dry fire extinguishing system, which can be recovered as heat and used effectively.
[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 process in which red-hot coke is charged into a pre-chamber from a coke charging inlet at an upper part of a cooling tower, and an inert gas is introduced from a lower part of the cooling tower to cool the red-hot coke. In the treatment of biomass such as wood and sewage sludge cake with fire extinguishing equipment, biomass is charged into the pre-chamber, and the biomass is pyrolyzed into combustible gas and biomass fixed carbon in the pre-chamber, and after pyrolysis. The combustion air for burning the biomass fixed carbon and the combustible gas is blown into the pre-chamber.
[0009]
In the present invention, the combustion air for burning the exhaust gas after burning the biomass-fixed carbon and the combustible gas after pyrolysis again may be blown into the annular duct and / or the flue, and the pre-chamber may be blown. Water and / or steam for controlling the temperature in the pre-chamber may be blown into the chamber.
[0010]
Further, in the method for treating biomass in the coke dry fire extinguishing equipment of the present invention, red-hot coke is charged into a pre-chamber from a coke charging inlet at the upper part of a cooling tower, and an inert gas is introduced from a lower part of the cooling tower to cool red-hot coke. In processing biomass such as wood and sewage sludge cake in a coke dry fire extinguishing facility, biomass is charged into the pre-chamber, and the biomass is pyrolyzed into combustible gas and biomass fixed carbon in the pre-chamber, and pyrolyzed. The combustion air for burning the biomass fixed carbon and the combustible gas is blown into the annular duct and the flue. At this time, the amount of combustion air blown into the annular duct for burning the pyrolyzed biomass fixed carbon and combustible gas is controlled by the gas temperature in the annular duct.
[0011]
Furthermore, in the present invention, biomass can be charged into the pre-chamber from two or more biomass loading ports, and the biomass is provided near the biomass loading port, and a cut-out / dispersion device equipped with rotary blades, or , Can be distributed into the pre-chamber by means of a chute whose inclination and / or direction can be changed.
[0012]
In the present invention, the charging of the biomass into the pre-chamber may be stopped or the charging amount may be reduced during a period in which the lid of the coke charging inlet is opened due to charging of the preheating chamber with red hot coke or the like.
[0013]
BEST MODE FOR CARRYING OUT 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-type fire extinguishing system that implements the biomass treatment method of the present invention. In the coke dry fire extinguishing equipment, the red hot coke 1 is opened from the coke charging inlet 3 in the upper part of the cooling tower 2, the lid 3 a is opened, then charged into the pre-chamber 4, lowered, and supplied from the cooling gas pipe 14 in the lower part of the cooling tower 2. The inert gas as a cooling gas was subjected to heat exchange with the red hot coke 1, and the high temperature inert gas recovered from the heat of the red hot coke 1 was introduced into the boiler 13 from the annular duct 5 through the flue 10 and heat exchanged. Thereafter, the circulating blower 15 pressurizes and circulates the cooling tower 2 underneath. 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 loading inlet 7 for wood, sewage sludge cake, and the like, and a combustion air inlet 8. Among the biomass, the wood is roughly pulverized to about 10 to 50 mm by a hammer crusher or the like (not shown) and is continuously charged from the biomass inlet 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. A cyclone 16 for dust separation is provided in a pipe between the boiler 13 and the circulation blower 15.
[0016]
In this coke dry fire extinguishing system, biomass is treated as follows.
[0017]
The biomass charged into the pre-chamber 4 from the biomass charging port 7 is thermally decomposed into flammable gas and biomass fixed carbon by the sensible heat of the red hot coke 1. The combustible gas generated by the thermal decomposition is burned 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 inserted biomass (hereinafter, referred to as “necessary air amount”) is introduced. Biomass-fixed carbon generated by pyrolysis is also burned with combustion air. The biomass-fixed carbon has a significantly lower strength than coke, and thus powders in the packed bed of the red hot coke 1. The powdered biomass-fixed carbon has a very large specific surface area as compared with the red-hot coke 1 and is highly flammable because it is made porous by thermal decomposition. 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. It is done efficiently.
[0018]
The exhaust gas that has finished burning contains a small amount of combustible matter due to the equilibrium reaction with the moisture, and is led to the flue 10 via the annular duct 5. In the flue 10, the combustion air is again continuously introduced from the combustion air inlet 9. Since the combustible content is small, it is completely burned even during a short residence time, is completely burned until 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. In this way, all the fixed carbon in the biomass raw material is burned and converted into exhaust gas sensible heat, and the heat is effectively exchanged and recovered by the boiler 13. As a result, a large amount of biomass can be treated by the coke dry fire extinguishing system, and the entire amount of heat possessed by the biomass can be recovered as heat and used effectively.
[0019]
Here, the combustion air for burning the exhaust gas after burning the biomass fixed carbon and the combustible gas after the pyrolysis again is introduced into the flue 10 as in the above embodiment, and the annular duct 5 is also used. Or may be introduced into both.
[0020]
On the other hand, when the lid 3a is opened, for example, when charging red hot coke, a large amount of air flows in from the coke charging inlet 3 at the top of the cooling tower 2. Therefore, if the pre-chamber 4 is filled with the combustible gas, there is a risk of explosion. Further, since 80% or more of biomass is a volatile component, a large amount of gas is released. When the total amount of the released gas and the amount of air flowing in from the coke inlet 3 exceeds the allowable amount of the circulation blower 15, the top of the cooling tower 2 has a positive pressure, and gas leaks from the coke inlet 3. Therefore, in processing the biomass, the charging of the biomass into the pre-chamber 4 is stopped or the charging amount is reduced while the lid 3a of the coke charging inlet 3 is opened. 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 configuration diagram of a coke dry fire extinguishing facility that implements another embodiment of the present invention. In the pre-chamber 4 of the coke dry-type fire extinguishing system shown in FIG. 2, a water and / or steam inlet 17 is provided in addition to the biomass inlet 7 and the combustion air inlet 8.
[0022]
As described above, when a large amount of biomass is burned in the pre-chamber 4 and is effectively used, a temperature rise occurs in the pre-chamber 4. This increase in temperature has a serious problem of melting the ash, as well as affecting the equipment. Generally, the melting point of ash contained in biomass is lower than the melting point of coal ash. Therefore, when the ash is burned at a high temperature, the ash is scattered in a semi-molten state, and adheres to a wall, a heat transfer tube, or the like, causing an adverse effect. Therefore, it is necessary to control the combustion temperature. Therefore, for temperature control when a large amount of biomass is burned in the pre-chamber 4, water / steam is blown from the inlet 17 as necessary to control the temperature. The injected water / steam causes a water gasification reaction (endothermic reaction) with the carbon content in the pre-chamber 4 and cools the pre-chamber 4. With this temperature control, it is possible to maximize the effective use of biomass without melting the ash, generating unburned gas, and discharging the recoverable heat as dust out of the system. Become.
[0023]
Example 3
FIG. 3 is a configuration diagram of a coke dry-type fire extinguishing facility that implements another embodiment of the present invention. In the coke dry fire extinguishing system shown in FIG. 3, a combustion air inlet 18 for introducing combustion air for burning the biomass fixed carbon and the combustible gas after pyrolysis is not provided in the pre-chamber 4 and the annular duct 5 is provided. And in the flue 10.
[0024]
As described above, it is difficult to completely burn the biomass fixed carbon generated by the thermal decomposition of the biomass because the residence time is too short just by introducing the combustion air into the flue 10. . Therefore, in the present embodiment, the combustion air is introduced into the annular duct 5 so that 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. However, if a large amount of combustion air is introduced into the annular duct 5, the temperature of the annular duct 5 increases significantly due to the heat of combustion, As described above, the temperature rise in the annular duct 5 causes the biomass ash to melt and adhere. In general, since the inner wall of the annular duct 5 has a single-layer structure of brick and has no strength at a high temperature, 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 at or below an allowable temperature. Therefore, in this embodiment, the temperature of the gas in the annular duct 5 is measured by a temperature sensor (not shown), and the 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 air to be blown is controlled, and the remaining amount of required air is blown into the flue 10.
[0025]
This method of blowing air for combustion makes it possible to prevent coke combustion, which is generated in a small amount when air is introduced into the pre-chamber 4, without causing loss of coke as a product and without melting ash. In addition, biomass can be effectively used to the maximum without generating unburned gas and without discharging recoverable heat as dust.
[0026]
Example 4
FIG. 4 is a configuration diagram of a coke dry-type fire extinguishing system that implements another embodiment of the present invention.
[0027]
When the throughput of the biomass is increased, the heat transfer efficiency is reduced and the temperature of the biomass is not increased, so that thermal decomposition and combustion are not reliably performed, and a portion where the thermal efficiency is reduced is generated. Then, the temperature of the portion becomes low, and if the portion exists near the inner wall of the cooling tower 2, the brick constituting the inner wall is also adversely affected. One of the factors that lower the heat transfer efficiency is the thickness of the filled biomass. That is, if there is a locally thick portion in the filling thickness, the temperature decreases due to the heat insulating effect of biomass, and the thermal efficiency of that portion decreases.
[0028]
Therefore, in order to increase the biomass throughput without lowering the thermal efficiency, it is necessary to uniformly load the biomass into the pre-chamber 4. For this reason, the coke dry fire extinguishing system of FIG. 4 is provided with two or more biomass inlets 7 so that the biomass can be dispersed in the pre-chamber 4 and can be charged as uniformly as possible.
[0029]
Further, as shown in FIG. 5, if a cut-out / dispersion device 19 provided with rotary blades is provided near the biomass charging inlet 7, the biomass can be more uniformly charged into the pre-chamber 4.
[0030]
Also, as shown in FIG. 6, by providing a biomass charging chute 20 whose inclination angle and / or direction can be changed near the biomass charging inlet 7, the biomass can be more evenly distributed in the pre-chamber 4. Can be charged
【The invention's effect】
In the method of treating biomass in the coke dry fire extinguishing system of the present invention, combustion air for burning the biomass-fixed carbon and combustible gas after pyrolysis is blown into the pre-chamber, so that most of the unburned gas is contained in the pre-chamber. Burned within. Therefore, a large amount of biomass can be effectively used without causing a corrosion problem of the equipment due to residual combustible gas. Further, since the biomass fixed carbon is also preferentially burned in the pre-chamber by the combustion air, the fixed carbon of the biomass charged can be recovered and effectively used as heat without recovering it as dust.
[0032]
Further, by blowing combustion air into the annular duct and / or the flue, it is possible to completely burn the biomass-fixed carbon, and it is possible to collect and effectively use the entire amount of heat possessed by the biomass as heat. It becomes possible. Furthermore, by blowing water and / or steam for temperature control into the pre-chamber, it is possible to suppress a rise in temperature in the pre-chamber, without causing adverse effects such as adhesion of ash in biomass having a low melting point due to melting. In addition, a large amount of biomass can be treated, and the entire amount of heat possessed by biomass can be recovered as heat and used effectively.
[0033]
Further, in the method for treating biomass in the coke dry fire extinguishing system of the present invention, the biomass fixed carbon is blown into the annular duct and the flue for burning the biomass fixed carbon and the combustible gas after pyrolysis, whereby the biomass fixed carbon is removed. It becomes possible to completely burn, and it becomes possible to collect and effectively use the entire amount of heat possessed by biomass as heat. When blowing combustion air into the annular duct, the amount of combustion air into the annular duct is controlled so that the temperature of the annular duct does not exceed the allowable temperature, and the remaining amount of required air is blown from the flue into the pre-chamber. Prevent combustion of coke that is generated in a small amount, and do not cause loss of coke as a product, do not cause adverse effects such as adhesion of ash in biomass with low melting point, and can process a large amount of biomass. In addition, the entire amount of heat possessed by biomass can be recovered as heat and used effectively.
[0034]
In addition, the biomass can be charged into the shake chamber from two or more inlets, a cutting and dispersing device having rotary blades is provided near the biomass inlet, and an inclination angle and / or is provided near the biomass inlet. By providing a biomass charging chute whose direction can be changed, the biomass can be dispersed in the pre-chamber and charged uniformly, preventing the temperature drop due to the heat insulation effect of the biomass, and the refractory due to temperature fluctuation. A large amount of biomass can be treated without causing adverse effects on biomass and without lowering thermal efficiency due to insufficient thermal decomposition and combustion of biomass, and the entire amount of heat possessed by biomass is recovered as heat and used effectively It is possible to do.
[0035]
In addition, gas leakage can be avoided by stopping the charging of the biomass into the pre-chamber or reducing the charging amount when the lid is opened, for example, when charging red hot coke.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a coke dry-type fire extinguishing facility for implementing a biomass treatment method of the present invention.
FIG. 2 is a configuration diagram of a coke dry-type fire extinguishing facility that implements another embodiment of the present invention.
FIG. 3 is a configuration diagram of a coke dry-type fire extinguishing system that implements another embodiment of the present invention.
FIG. 4 is a configuration diagram of a coke dry-type fire extinguishing facility that implements another embodiment of the present invention.
FIG. 5 is a view showing a dispersing and dispersing apparatus provided near a biomass loading port.
FIG. 6 is a view showing a biomass charging chute provided near a biomass charging inlet.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 red hot coke 2 cooling tower 3 coke inlet 3a coke inlet lid 4 prechamber 5 annular duct 6 coke outlet 7 biomass inlet 8 combustion air inlet 9 combustion air inlet 10 flue 11 collision wall 12 dust Catcher 13 Boiler 14 Cooling gas pipe 15 Circulating blower 16 Cyclone 17 Water and / or steam inlet 18 Combustion air inlet 19 Cutting and dispersing device 20 with rotary blades 20 Chute for charging biomass

Claims (9)

Red-hot coke is charged into the pre-chamber through the coke charging inlet at the top of the cooling tower, and inert gas is introduced from the bottom of the cooling tower to cool red-hot coke. In doing so, biomass is charged into the pre-chamber, and the biomass is thermally decomposed into combustible gas and biomass fixed carbon in the pre-chamber, and used for burning the pyrolyzed biomass fixed carbon and combustible gas. A method for treating biomass in a coke dry fire extinguishing facility, characterized by blowing air into a pre-chamber. The coke dry process according to claim 1, wherein combustion air for reburning the exhaust gas after burning the biomass fixed carbon and the combustible gas after the pyrolysis is blown into the annular duct and / or the flue. A method for treating biomass in fire extinguishing equipment. The method for treating biomass in a coke dry-type fire extinguishing facility according to claim 1 or 2, wherein water and / or steam for controlling the temperature in the pre-chamber is blown into the pre-chamber. Red-hot coke is charged into the pre-chamber through the coke charging inlet at the top of the cooling tower, and inert gas is introduced from the bottom of the cooling tower to cool red-hot coke. In doing so, biomass is charged into the pre-chamber, and the biomass is thermally decomposed into combustible gas and biomass fixed carbon in the pre-chamber, and used for burning the pyrolyzed biomass fixed carbon and combustible gas. A method for treating biomass in a coke dry fire extinguishing system, characterized by blowing air into an annular duct and a flue. The coke dry method according to claim 4, wherein the amount of combustion air blown into the annular duct for burning the pyrolyzed biomass fixed carbon and combustible gas is controlled by the gas temperature in the annular duct. A method for treating biomass in fire extinguishing equipment. The method for treating biomass in a coke dry fire extinguishing facility according to any one of claims 1 to 5, wherein the biomass is charged into the pre-chamber through two or more biomass charging inlets. The coke dry process according to any one of claims 1 to 6, wherein the biomass is dispersed and charged into the pre-chamber by a cutting and dispersing device provided with a rotary blade provided near a biomass charging inlet. A method for treating biomass in fire extinguishing equipment. The biomass is dispersedly charged into the pre-chamber by a chute provided near a biomass charging inlet and having a tilt angle and / or a direction that can be changed, and the biomass is charged into the prechamber according to any one of claims 1 to 6. A method for treating biomass in a coke dry fire extinguishing system. The charging of the biomass to the pre-chamber is stopped or the charging amount is reduced during a period in which the lid of the coke charging inlet is opened by charging red hot coke to the pre-chamber or the like. A method for treating biomass in a coke dry-type fire extinguishing facility according to claim 1.

Images