JP2003279015A - Biomass thermally-decomposed gas combusting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a clean produced gas of high calorie by drying and thermally decomposing biomass of high wetness to be effectively utilized as a heat source for drying and thermally decomposing the biomass in a system, and to extract the char of little water content as a valuable resource. <P>SOLUTION: A drying furnace (drying zone) 2 and thermal decomposition furnaces (thermal-decomposition gasifying zone) 3a-3c located at the back of the drying furnace are mounted inside of a hot air furnace 1, a generated vapor passage 4 from the drying zone 1 and a produced gas passage 5 from the thermal decomposition gasifying zone 3 are separated from each other, and the produced gas passage 5 is connected to a combustion part 6 of the hot air furnace. By compensating the shortage of calories of a gas turbine waste gas by the thermally decomposed gas of high calorific power not diluted by the dry vapor as the hot air furnace heat source, the energy is saved on. The dried water content taken out from the drying zone is deodorized in the hot air furnace, and further the char of low water content is extracted as the valuable resource. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biomass pyrolysis gas combustion method, and more particularly to a highly moist biomass (for example, woody matter, sludge, manure, food residues, food waste, rice husks, beer residue, etc.). Waste) pyrolysis gas efficient combustion technology.

[0002]

2. Description of the Related Art For example, livestock excrement has been exposed to environmental deterioration due to conventional field loading and ocean dumping.
Regulations on the treatment of livestock manure, etc., and the establishment of legislation such as the Food Waste Recycling Law for food residues, etc. are required to properly treat these biomasses.

[0003] It has been conventionally known that pyrolysis of biomass produces pyrolysis gas, char, tar and the like. The amount and composition of each of these differ depending on the operating temperature of the gasifier based on heating.

As a technique of this kind, Japanese Patent Laid-Open No. 10-330 is known.
Japanese Unexamined Patent Publication No. 760 describes a continuous carbonization device for organic substances. This example is a drying furnace, charcoal furnace, deodorizing drum, hopper,
The steam generated in the drying furnace is sent to the carbonization furnace together with the dry matter as it is, and mixed with the gas generated in the carbonization furnace to become a low-calorie pyrolysis product gas to become a deodorizing drum. Was sent to.

[0005]

DISCLOSURE OF THE INVENTION In order to effectively utilize the above-mentioned pyrolysis product gas, the present inventors dry biomass having a high water content for a certain period of time in a drying step, and then pyrolyze it in the pyrolysis step. The pyrolysis gas that produces gas and combines this gas with the vapor evaporated in the drying process is mixed with the exhaust gas of the gas turbine (waste heat temperature is about 500 ° C.) to support combustion (about A technique for performing further heating at 500 ° C. has been developed (see Japanese Patent Application No. 2002-030815).

By the way, when livestock manure (cow dung) is used as a raw material, its composition is C (52.4%), H (7.1%),
It becomes N (2.8%) and O (37.7%). Ash has 16.9% of these elemental components and a water content of 88.3%.

The calorific value of the thermal decomposition gas after thermal decomposition (heating at an external heat temperature of about 800 ° C.) in this composition (composition in the case of general cow dung) is due to the presence of water vapor evaporated in the drying process. It was extremely low and had a problem with flammability.

The composition (vol. Ratio) and heat generation amount of the conventional decomposition gas in which this evaporated water is mixed are shown below. For example, it can be seen that the calorie content is extremely low even when compared with about 9900 kcal of general city gas.

Combustible components: 0.02766 CO ₂ and other non-combustible components: 0.0181 H ₂ O: 0.95423 Calorific value (LHV): 237 kcal / Nm ³

As a solution to this problem, there is a means for taking out the produced gas mixed with dry steam from the gas passage and washing it with water to remove excess water, but this is not a good idea because it causes heat loss.

The object of the present invention is to dry and pyrolyze highly moist biomass to obtain a high calorie and clean product gas, which is effectively used as a heat source for biomass drying and pyrolysis in the system, and which is also included. It is to collect char with a small amount of water as a valuable resource.

[0012]

[Means for Solving the Problems] The above objects are a drying zone for drying biomass, a pyrolysis gasification zone for pyrolyzing the biomass dried in the drying zone to produce pyrolysis gas and char, and the drying. A zone and a hot air stove that generates combustion gas for heating the pyrolysis gasification zone, a dry steam passage for taking out dry steam of biomass from the drying zone and feeding it to the hot air stove, and the pyrolysis The pyrolysis gas passages for taking out the pyrolysis gas from the gasification zone and supplying it to the hot blast stove are separately arranged, the pyrolysis gas is supplied to the combustion section of the hot blast stove, and the dry steam is the hot air blast. This is achieved by a biomass pyrolysis gas combustion method, which is characterized in that the biomass is fed to a place different from the combustion part to perform deodorizing treatment.

According to the present invention, the steam generated in the biomass drying zone is taken out in advance, and the dry biomass in which the steam is not mixed is fed to the pyrolysis gasification zone, so that it is generated in the pyrolysis gasification zone. Pyrolysis gas and char do not contain evaporated water in the drying zone, and can be effectively used as a high-calorie fuel. In the present invention, this pyrolysis gas was used as the heat source of the hot stove that heats the drying zone and the pyrolysis gasification zone. Further, the dry steam separately taken out in the drying zone was supplied to a wake side different from the combustion part in the hot air stove to deodorize.

Further, stable combustion can be maintained by supplying the external fuel together with the pyrolysis gas as the heat source of the hot stove. Further, by sending the exhaust gas of the gas turbine or the gas engine to the hot stove as combustion air, the waste heat of these high efficiency heat engines can be effectively used. Moreover, high-calorie char containing no biomass dry steam can be taken out as valuables from the pyrolysis gasification zone.

FIG. 1 is a graph showing the change over time in the thermal decomposition of biomass. There is a rapid weight loss up to 15 minutes, but this is mostly due to the generation of steam in the drying zone,
It can be seen that about 70% of the weight of biomass is reduced as evaporated water, and after passing through it, combustible gas is gradually generated instead of steam.

That is, from the above graph, it is suggested that it is possible to prevent a decrease in the calorific value of the produced gas in the pyrolysis gasification zone by distinguishing the drying zone from the pyrolysis zone and taking out the steam in the drying zone separately. .

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The outline of the embodiment of the present invention is that the pyrolysis gas of biomass is effectively used as a high-calorie fuel, and at the same time, the char produced by the pyrolysis is collected as a valuable resource. Evaporated moisture generated is taken out separately, and in the pyrolysis gasification zone on the downstream side, the biomass that does not contain dry moisture is pyrolyzed to generate pyrolysis gas and char with extremely low water content. is there.

The high-calorie pyrolysis gas is effectively used as a heat source for a hot-blast stove that heats the drying zone and the pyrolysis-gasification zone in the system, and the dry water taken out in the drying zone is deodorized in the hot-blast stove. I chose

FIG. 2 is a constitutional view showing an example of a pyrolysis gasification apparatus adopting the biomass pyrolysis gas combustion method of the present invention. Drying furnace (drying zone) 2 in hot blast stove 1 and thermal decomposition furnaces 3a to 3c as pyrolysis gasification zone 3 in the subsequent stage.
Is installed.

A partition plate 11 is provided in the hot-air stove 1, and a passage for a combustion gas 12 for heating the drying furnace 1 and the thermal decomposition furnaces 3a to 3c from the outside is formed. Combustion gas 12
Is sequentially discharged from the outside through the pyrolysis gasification zone 3 and the drying zone 2 while passing through this passage, and then discharged from the discharge port 13.

In this example, the steam generation passage 4 from the drying furnace 1
And the generated gas (pyrolysis gas) passage 5 from the thermal decomposition furnaces 3a to 3b are separated, and the pyrolysis gas passage 5 is connected to the combustion part 6 of the hot stove. As a result, since the pyrolysis gas is not diluted with steam, it is possible to maintain a high calorific value and facilitate combustion.

In this example, the exhaust gas 7 of the gas turbine is used to generate the combustion gas in the hot stove, but the pyrolysis temperature at which the biomass is pyrolyzed is usually 600 to 800 ° C. On the other hand, since the gas turbine exhaust gas 7 has a temperature of about 500 ° C., it is not possible to raise the temperature to the thermal decomposition temperature only by the amount of heat of the exhaust gas 7.

Therefore, an additional heating burner 8 for heating the gas turbine exhaust gas 7 is provided to compensate for the insufficient heat quantity of the exhaust gas. In this case, energy is saved by burning a high-calorie generated gas that does not contain dry water generated in the thermal decomposition furnace to raise the temperature of the gas turbine exhaust gas to the thermal decomposition temperature.

Further, by supplementing the additional burner 8 of the hot stove with fossil fuel such as kerosene or external fuel such as city gas, the combustion of the hot stove can be further stably maintained. If necessary, it is possible to burn the hot stove using only the external fuel and effectively use the high-calorie pyrolysis gas for other purposes.

Further, the dry steam separately taken out from the drying furnace is placed together with the air (gas turbine exhaust gas in this example) in a place different from the pyrolysis gas combustion section 6 in the hot stove (shown as dry steam and air 15). Add to deodorize. Further, the char 16 discharged from the pyrolysis gasification zone 3
Also, since the dry water content of the biomass has been removed in advance in the drying zone 2, high-calorie char with a low water content can be collected as a valuable resource.

Next, the method of the present invention in which the waste heat of the gas turbine is effectively used and the measures against high calorie of the produced gas are taken as described above, and the manure carbonization treatment using other fuels are carried out in terms of energy cost unit The comparison results are shown in Table 1 below.

That is, the conventional case in which cow dung is dried and carbonized by using kerosene as fuel is referred to as case 1, and the case in which cow dung is dried and carbonized by utilizing the gas turbine waste heat according to the present invention is compared as case 2.

In case 1 of the conventional case, kerosene of 30 liters is used, and the annual cost is 92,880,000 yen, and the cost is 2,300 yen per ton of manure. On the other hand, in case 2 according to the present invention, the cost of using kerosene is 100,253,000 yen per year, but as a merit of power generation, with a 1000 kW gas turbine (operating time 8000 hr), 96,000,000 yen (electric power unit price 12 yen / kWh) Is amortized, and after all 110 tons of manure can be processed for 110 yen.

[0029]

[Table 1]

As described above, it is understood that the pyrolysis carbonization (charification) treatment system for heating by using the waste heat of the gas turbine by the method of the present invention is extremely excellent. At this time, the valuable material is char, which is effectively used as a substitute for fuel or fertilizer. In addition, the discharge to the outside of the system in this processing apparatus is only the combustion gas of the hot stove, which reduces the load on the environment.

[0031]

As described above, according to the present invention, by removing the dry water generated in the drying zone in advance, it is possible to generate a high-calorie pyrolysis gas in which the dry water is not mixed. By utilizing it as a heat source for decomposition, a highly efficient biomass pyrolysis gas combustion method can be obtained. Further, since the dry steam taken out in advance in the drying zone is deodorized by the hot-air stove, it is possible to maintain extremely efficient combustion and deodorize the generated steam with a simple structure.

[Brief description of drawings]

FIG. 1 is a graph showing the change over time in the thermal decomposition of biomass in the present invention.

FIG. 2 is a diagram showing an example of the configuration of the biomass pyrolysis gas combustion method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Hot-blast stove 2 Drying furnace (drying zone) 3, 3a, 3b, 3c Thermal decomposition furnace (pyrolysis gasification zone) 4 Steam passage 5 Product gas (pyrolysis gas) passage 6 Combustion part 7 Gas turbine exhaust gas 8 Burner 10 Biomass 11 Partition Plate 12 Hot Stove Combustion Gas 15 Dry Steam and Air 16 Char

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C10J 3/00 C10J 3/00 A 4H012 F23G 5/04 F23G 5/04 J 5/16 5/16 B F term (reference) ) 3K061 AA18 AB02 AC02 AC12 AC17 BA04 CA01 CA07 3K065 AA18 AB02 AC02 AC12 AC17 BA04 CA12 3K078 AA04 BA10 CA07 4D004 AA02 AA04 AA12 BA03 BA04 CA24 CA42 CA48 JA57 JA07 CA01 CA07 CA01 CA01 CA01 CA01 CA07 CA01 CA07 CA47 CA02 CA16 CA02 CA16 CA02 CA16 CA02 CA16 CA02 CA16 CA02 CA16 CA02 CA16 CA02 CA16 CA02 CA01 CA07 CA07 CA01 JA11

Claims (4)

[Claims] 1. A drying zone for drying biomass,
A pyrolysis gasification zone for pyrolyzing the biomass dried in the drying zone to produce pyrolysis gas and char, and a hot stove producing a combustion gas for heating the drying zone and the pyrolysis gasification zone. A dry steam passage for taking out dry steam of biomass from the drying zone and feeding it to the hot stove, and a pyrolysis gas passage for taking out the pyrolysis gas from the pyrolysis gasification zone and supplying it to the hot stove. And separately disposed, the pyrolysis gas is supplied to the combustion part of the hot stove, and the dry steam is sent to a place different from the combustion part in the hot stove to perform deodorizing treatment. And biomass pyrolysis gas combustion method. 2. The biomass pyrolysis gas combustion method according to claim 1, wherein exhaust gas from a gas turbine or a gas engine is fed to the hot stoves as combustion air. 3. The biomass pyrolysis gas combustion method according to claim 1, wherein external fuel is supplied to the combustion section of the hot stove. 4. The char is taken out as valuables from the pyrolysis gasification zone.
3. The biomass pyrolysis gas combustion method according to any one of 3 above.