JPS6046322B2 - Furnace combustion method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for effectively utilizing high-temperature exhaust gas from a heavy oil heating furnace used as a rolling heating furnace or the like.

Exhaust gas from a heavy oil heating furnace has an outlet temperature of, for example, 800 to 90
It is extremely high at 0'C, and has traditionally been used for heat exchange with combustion air or fuel, but this has only been used for the obvious use of exhaust gas.

Also, there is CO in these exhaust gases. ,H. No, along with O etc.
Because of this, exhaust gas treatment has become an issue from the standpoint of pollution prevention. From this perspective, the present inventors have conducted research on the effective use of exhaust gas from heavy oil heating furnaces and have arrived at the present invention.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. The exhaust gas from the heating furnace 1, which uses heavy oil F as fuel, has an extremely high temperature of 800 to 900°C, and contains CO2 and H.
It contains various nitrogen oxides NOx along with O, etc., and it is not preferable to release it into the atmosphere as it is due to pollution problems. Therefore, NO in this exhaust gas is reduced to harmless N2, and CO as well. ,H. If combustible gas such as Co)H2 can be produced from O etc., it is extremely preferable in terms of pollution prevention and effective use of exhaust gas. The present invention was able to solve this problem by combining a heavy oil heating furnace and a special reduction furnace. That is, in the present invention, high-temperature exhaust gas from the heating furnace 1 is transferred to the reducing furnace 2 filled with coke non-caking coal or high volatile coal C.
The following reactions are caused to take place in the furnace by whitening the coal by blowing air into the furnace. C +C02-2
CO CfH20→ Co+H2 CfNOx→ N2+Co That is, by burning coal in a reducing atmosphere, CO2 and H2O in the exhaust gas are converted to Co)Ho, producing flammable gas, and NOx is effectively converted to harmless N2. It will be done.

This combustible gas, which is a metamorphosed gas, contains coal volatile matter in addition to the components listed in Table 1, so the tar content was removed using a deterrer 3, and a part of the high-calorie combustible gas was temporarily stored in a gas holder 4. Afterwards, the fuel can be heated in the heat exchanger 5 if necessary and then reused as fuel in the heating furnace.

Furthermore, since the nitrogen content in the combustible gas has been reduced to harmless N2, it can be released into the atmosphere as is. In addition, AS in the figure
is the ash originating from the reduction furnace, P is the gas blowing fan, and G is the exhaust gas. As described above, according to the present invention, part of the exhaust gas becomes a closed system and is reused, reducing the amount of heavy oil fuel consumed in the heating furnace.In conjunction with this, the amount of released NOx is also significantly reduced, and furthermore, the amount of NOx released is reduced significantly. Since it is rendered harmless by the furnace, it is useful for reducing fuel consumption in the heating furnace and for preventing pollution.

The calorie of the combustible gas obtained by metamorphosis from the reduction furnace is 1250K-Cal even if the coal is combusted by air injection.
/d, which shows a high calorie, but if 02 is added to the reduction device, it is possible to produce a modified gas with an even higher calorie. In addition, the flammable gas from the deterrer can be circulated directly to the heating furnace 1, or as mentioned above, it can be stored in the gas holder and then sent to the heating furnace. Preferably, the gas is heated by heat exchange with another heat source.

This heat exchange can be carried out using any heat source, but for example, as shown by dotted lines in the attached figure, two or more heating furnaces 6 are arranged in parallel, and the high-temperature exhaust gas from the second heating furnace 6 is exchanged with the heat exchanger. Heat exchange is performed by an exchanger 5, and air A is sent to another heat exchanger 7 for the sensible heat of the exhaust gas from another second heating furnace 6, and the heated air is transferred to the first heating furnace 1, reduction furnace 2, or second heating furnace. It is particularly preferable to use it in the heating furnace 6 to further increase thermal efficiency. As described above, by carrying out the present invention, the heating furnace exhaust gas is effectively utilized, and it is also useful for preventing pollution, making it possible to utilize the exhaust gas in an industrially extremely effective manner.

[Brief explanation of the drawing]

FIG. 1 is a raw sheet showing each processing step of the method of the present invention. In the figure, 1 is a heating furnace, 2 is a coal-filled reduction furnace, 3 is a dethaller, 4 is a gas holder, 5 is a heat exchanger, 6 is a second heating furnace, 7 is a heat exchanger, F is heavy oil, and AS is ash content , P is a fan,
G is exhaust gas, A is air, and G″ is exhaust gas from the second heating furnace.

Claims (1)

[Claims] 1 High-temperature exhaust gas from a heavy oil heating furnace is passed through a reduction furnace filled with coke, non-caking coal, or high-volatile coal to reduce C in the exhaust gas.
A combustion method for a heating furnace, characterized in that O_2 and H_2O are reduced and transformed into combustible gases such as CO and H_2, and the combustible gases are recycled and used in the heating furnace.