Gas combustion treatment method and apparatus therefor

Abstract

A gas combustion treatment method for the combustion treatment of an ammonia-containing gas and a hydrogen sulfide-containing gas, the method comprising a first combustion treatment step in which the ammonia-containing gas, together with a fuel, is introduced and burned; a nitrogen oxide reduction step downstream of the first combustion treatment step, in which a portion of the hydrogen sulfide-containing gas or the ammonia-containing gas is introduced and the nitrogen oxides produced in the first combustion treatment step are reduced in a reducing atmosphere; and a second combustion treatment step downstream of the nitrogen oxide reduction step, in which the remaining hydrogen sulfide-containing gas, together with air, is introduced and burned. The present invention provides a combustion apparatus suitable for use as a combustion furnace for off-gases resulting from the wet purification of coal gasification gas.

Description

CROSS REFERENCE TO A RELATED APPLICATION [0001] This application is a divisional of U.S. patent application Ser. No. 10 / 245,326, filed Sep. 18, 2002, now allowed, which claims priority to Japanese patent application No. 2001-329190, filed Oct. 26, 2001, both of which are hereby incorporated by reference in their entirety.FIELD OF THE INVENTION [0002] This invention relates to gas combustion treatment methods and gas combustion apparatus. More particularly, it relates to a combustion apparatus suitable for use as a combustion furnace for off-gases resulting from the wet purification of coal gasification gas, and a combustion method therefor. BACKGROUND OF THE INVENTION [0003] When coal is gasified and used as a fuel for electric power generation, sulfur compounds (e.g., hydrogen sulfide and carbonyl sulfide) and nitrogen compounds such as ammonia are contained in the product gas. From the viewpoint of environmental protection and corrosion prevention, these compounds are removed in w...

AI Technical Summary

Benefits of technology

The present invention provides a method and apparatus for the efficient treatment of ammonia-containing gas and hydrogen sulfide-containing gas. The method involves a three-stage combustion apparatus that reduces nitrogen oxide production and the need for separate treatment of NH3 off-gas and H2S off-gas. The apparatus includes a first combustion section for burning NH3 off-gas and a nitrogen oxide reduction section for reducing NOx. The second combustion section then burns the remaining H2S off-gas and air. The method and apparatus can effectively treat these gases with reduced costs and low environmental impact.

Problems solved by technology

However, storage type combustion furnaces have problems in that they require a valve mechanism for carrying out operation while changing a plurality of flow paths in order to maintain the effectiveness of heat exchange and its operating procedure is troublesome.

Moreover, they are disadvantageous from the viewpoint of reliability ensuring freedom from troubles such as failure.

On the other hand, when conventional storage type combustion furnaces (at 1,000° C.) are used for the combustion treatment of NH3 off-gas, the complete combustion treatment of NH3 cannot be achieved to cause a leak of NH3 to the downstream side.

Although a high combustion temperature (about 1,500° C.) is required to decompose NH3 completely, the operating temperature of storage type combustion furnaces has been limited to about 1,000° C. owing, for example, to the endurable temperature limits of heat reservoirs comprising mullite and cordierite (high-temperature ceramic materials).

However, in order to maintain a high temperature of about 1,000° C. or above under a reducing atmosphere, it is necessary to burn a large amount of additional fuel.

Moreover, a large-sized combustion apparatus adapted for high-temperature conditions is required, and this is not economical from the viewpoint of operation and equipment investment.

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