Advances in Ammonia Removal from Hot Coal Gas

摘要

Nitrogen occurs in coal in the form of tightly bound organic ring compounds, typically at levels of 1 to 2 wt%. During coal gasification, this fuel bound nitrogen is released principally as ammonia (NH(sub 3)). When hot coal gas is used to generate electricity in integrated gasification combined cycle (IGCC) power plants, NH(sub 3) is converted to nitrogen oxides (NO(sub x)) which are difficult to remove and are highly undesirable as atmospheric pollutants. Similarly, while the efficiency of integrated gasification molten carbonate fuel cell (IGFC) power plants is not affected by NH(sub 3), NO(sub x) is generated during combustion of the anode exhaust gas. Thus NH(sub 3) must be removed from hot coal gas before it can be burned in a turbine or fuel cell. The objective of this study is to develop a successful combination of an NH(sub 3) decomposition catalyst with a zinc-based mixed-metal oxide sorbent so that the sorbent-catalyst activity remains stable for NH(sub 3) decomposition in addition to H(sub 2)S removal under cycle sulfidation-regeneration conditions in the temperature range of 500 to 750(degrees)C.