JPS61208420A - Method of combustion in dry retorting distillation gasification furnace - Google Patents

Abstract

PURPOSE:To cause the red-heated residual carbon to generate a combustible gas and at the same time prevent the formation of clinker by restricting the amount of the introduced air before the end of operation and mixing the air with the exhaust gas from an exhaust gas recycling duct and introducing the mixture into a dry distillation gasification furnace. CONSTITUTION:An exhaust gas recycling duct 17 having a gas flow rate regulator valve 16 is branched from a smoke stack and the duct 17 is installed to a gas cleaner 14 on its inlet side. An air inlet pipe 19 with a flow rate regulator valve 18 is connected to the duct 17. A mixture gas of air and exhaust gas is introduced by a blower 20 into a dry distillation gasification furnace 1 through its inlet 7. When the operation approaches the end, the air regulating valve 18 is operated and the amount of air introduced is restricted to a lower amount than in ordinary operation, and the recycling exhaust gas is led out from the duct 17. Accordingly the oxygen level in the dry distillation gasification furnace 1 is lowered and the furnace temperature becomes low, generating a gas with clinker formation prevented, while the heat quantity of the generated gas and red-heated residual carbon and red heat ash is transferred to a combustion furnace 8 by means of the added recycling exhaust gas, and they burn in the furnace 8. The recycling exhaust gas that does not participate in the combustion works as a heat carrier.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention prevents the generation of clinker in the hearth, which is likely to be generated especially at the end of operation, when carbonizing tires, plastic waste oil, industrial waste, etc. The present invention also relates to a combustion method in a carbonization gasification furnace for increasing the amount of combustible gas.

(Prior technology) Conventionally, mechanical stoker furnaces have been widely used in waste incineration equipment, but these furnaces are capable of gasifying waste and generating gas.
Since the combustion of phosphorus and phosphorus occur almost simultaneously, gasification and combustion are incomplete, and soot and unburned phosphorus remain in the exhaust gas, polluting the atmosphere and causing secondary pollution. was.

To prevent this, combustion devices that distinguish between gasification and combustion have recently been developed.

As mentioned above, a carbonization gasification furnace is used to gasify waste. In a carbonization gasification furnace, approximately 30% of the theoretical air amount is introduced to remove oil, wood, plastic, etc. from the waste. It is thermally decomposed to generate flammable gas, then carbonized, and a portion of it generates carbon monoxide, which is taken out as carbonized gas, and the residual carbon and ash in the furnace remain in a red-hot state. Thermal energy of the generated carbonized gas is recovered by a boiler or combustion furnace.

Particularly in the batch carbonization method, combustion and shutdown occur frequently, but if air supply is continued in the same way as during normal operation before the end of operation, approximately 30% of the theoretical amount of air can be introduced. In addition, the amount of oxygen becomes excessive with respect to the residual carbon content mentioned above, and the temperature rises too much, and the combustion becomes intense and the natural gas itself melts and becomes clinker, and furthermore, if there is melted glass etc. in the waste If there is a material that is easy to melt, it will melt and create a talin force within the ash layer, blocking the air flow path and making it difficult to remove the ash layer, and in some cases, forcing heavy labor such as crushing it by hammering. To avoid this, if the amount of air is excessively restricted, the furnace temperature will drop and clinker generation can be prevented, but because the amount of air is reduced, the carbonization gas cannot be transferred to the next stage combustion furnace, and There is a drawback that recovery is also insufficient.

Such an operation can also occur at the end of combustion in a carbonization gasifier in a continuous carbonization system.

In the 1970s, this technology was developed as an advanced technology to suppress the temperature rise of the carbonization gasifier by distinguishing between the carbonization gasification furnace and the combustion furnace when burning waste, and controlling and recirculating the combustion exhaust gas to the carbonization gasification furnace.
There is an incinerator described in Publication No. 6749, in which the supply of air is stopped to the carbonization gasifier called the first combustion chamber, and only circulating exhaust gas is used, the amount of which is adjusted to create a steaming state, and the combustible material is input. At the same time, the fuel is gasified by thermal decomposition while trying to prevent the generation of black smoke that occurs when the temperature of the first combustion chamber increases.

(Problem to be solved by the invention) However, the waste input is rubber, plastic.
Since there are various types of industrial waste, etc., the oxygen content remaining in the combustion exhaust gas becomes unstable, so in the prior art, the supply of air to the first combustion chamber is stopped. Even if the flow rate of combustion exhaust gas is controlled, it is difficult to maintain an appropriate oxygen concentration, and no consideration should be given to preventing clinker generation and the effective use of combustible materials that still remain in the furnace at the end of steaming and can be gasified. There are problems such as not being paid.

(Means for Solving the Problems) In view of the above, the present invention gasifies the residual carbon that remains in a red-hot state before the end of the operation of the carbonization gasifier at a low temperature, and facilitates the transfer of the generated carbonization gas. The purpose of the present invention is to provide a carbonization gasification furnace combustion method for cooling and recovering heat in the red-hot state and further preventing the generation of clinker in the ash layer. In a combustion apparatus equipped with a carbonization gas combustion furnace and an exhaust gas circulation pipe that branches from the combustion furnace flue and connects to the carbonization gasification furnace, an appropriate amount of air is introduced into the carbonization gasification furnace during normal operation. This is a carbonization gasifier combustion method in which carbonization gas is generated, the amount of introduced air is limited before the end of operation, and the mixture is mixed with exhaust gas from an exhaust gas circulation pipe and introduced into the carbonization gasification furnace.

(Embodiment) The figure is a flow sheet in one embodiment of the present invention, and as shown in FIG. 3 is provided in the upper part, a fixed retort 4 is provided in the lower part, an ignition device 5 is attached to the side wall, a gas outlet 6 is connected to the upper part of the side wall, and a mixed gas of air and circulating exhaust gas is provided in the lower part. The human loa is open. Separate inlet pipes may be installed for air and circulating exhaust gas.

The combustion furnace 8 is arranged horizontally, for example, and is connected to the carbonization gasification furnace 1 through a gas pipe 9, and has a secondary air inlet 11 connected to a fan 10 in its periphery, and a boiler water pipe for waste heat recovery inside. 12 is installed, and a heat recovery device 13 is installed on the furnace exit side, which is further connected to a chimney 15 via an exhaust gas purifier 14.

An exhaust gas circulation pipe 17 branching from the flue and having a gas flow rate control valve 16 is provided on the inlet side of the exhaust gas purifier 14,
The pipe line 17 includes an air introduction pipe 19 having a flow rate control valve 18.
A mixed gas of air and exhaust gas is introduced into the carbonization gasification furnace 1 from the input lower via the blower 20. 21
is a filter.

In the combustion apparatus having the above configuration, the waste 22 put into the carbonization gasifier is ignited by the ignition device 5, and the air, which is adjusted to about 30% of the theoretical air amount by the flow control valve 18, is sent to the fan 20. Normal operation is carried out by supplying power from Combustible materials form a preheating layer, reduced layer, oxidized layer, and ash layer, and generate carbonized gas.

The generated carbonized gas then enters the combustion furnace 8 and enters the ignition burner 23.
The combustion continues for m due to the supply of secondary air from the air inlet 11, and the heat energy is transferred to the waste heat recovery boiler 12.
, the heat is recovered by the heat recovery device 13.

The input waste 22 decreases as it is gasified, the residual carbon becomes red hot, the amount of gas generated decreases, and the operation is nearing completion.

Here, the air control valve 18 is operated to limit the amount of air to below the amount of air during normal operation, and the circulating exhaust gas is guided through the pipe 17. Therefore, the amount of oxygen in the carbonization gasification furnace 1 disappears and the temperature becomes low, and gas is generated while preventing the generation of clinker.At the same time, the calorific value of the generated gas, red residual carbon, and red hot ash is transferred to the combustion furnace by the added circulating exhaust gas. 8 and burned.

The circulating exhaust gas, which is not involved in combustion, acts exclusively as a heat transfer medium for the heat recovered from the red-hot residual carbon and red-hot ash to the waste heat recovery boiler and waste heat recovery device.

(Effects) The present invention provides a combustion apparatus equipped with a carbonization gasification furnace, a carbonization gas combustion furnace, and an exhaust gas circulation pipe that branches from the combustion furnace flue and connects to the carbonization gasification furnace. amount is introduced into the carbonization gasification furnace, and before the end of operation, the amount of air introduced is limited, circulating exhaust gas is introduced to keep the temperature inside the carbonization gasification furnace at a low temperature, and flammable gas is generated from residual carbon. This carbonization gasifier combustion method is characterized by reducing the amount of combustibles and preventing the generation of talin force, so as the combustibles are gasified in the carbonization gasifier, the combustibles decrease at the end of operation and gas generation is reduced. Even if the amount of red-hot carbon and red-hot pressure remains, a more limited amount of air is introduced than during normal operation, and circulating exhaust gas is introduced, so flammable gas is generated from the red-hot carbon. At the same time, the combustible gas can be transported by the circulating exhaust gas and reach the combustion furnace, and the amount of thermal energy is further increased by combustion, so that the combustible material in the input waste can be used without wasting it.

In addition, the red-hot carbon remaining in the carbonization gasifier is combusted by the more limited amount of air and the circulating exhaust gas, which has a lower oxygen content than the outside air, so the excessive combustion temperature becomes low and the generation of coal carbon can be prevented. effective.

[Brief explanation of drawings]

The figure is a flow sheet in one embodiment of the present invention. 1... Carbonization gasifier, 3... Waste injector, 4...
...Fixed retort, 5. Ignition device, 7. Mixed gas inlet, 8. Combustion furnace, 11. Secondary air inlet, 12. Boiler water pipe for waste heat recovery, 13. ...Heat recovery device, 14...Exhaust gas purifier,
15...Chimney, 16...Gas flow rate control valve, 17...Exhaust gas circulation pipe, 19...Air introduction pipe.

Claims (1)

[Claims] In a combustion apparatus equipped with a carbonization gasification furnace, a carbonization gas combustion furnace, and an exhaust gas circulation pipe that branches from the combustion furnace flue and connects to the carbonization gasification furnace, during normal operation, an appropriate amount of air is supplied to the carbonization gasification furnace. Carbonization gasifier combustion characterized by introducing carbonization gas into the carbonization gasifier, restricting the amount of introduced air before the end of operation, mixing it with exhaust gas from the exhaust gas circulation pipe, and introducing it into the carbonization gasifier. Method.