Formation and Removal of Nitrogen Compounds in Gasification Processes

When gasifying nitrogenious fuels, organic and inorganic nitrogen compounds form in the gas. The main nitrogen compound in gasification atmosphere is ammonia. The ammonia content of the product gas has ranged in pressurized peat gasification processes between 6 000-13 400 ppm and hydrogen cyanide content 10 - 500 ppm. Decomposition and removal of nitrogen compounds can be accelerated by catalysis. The effect of several catalytic materials on the nitrogen compounds from an operating peat gasifier was measured. Nickel catalyst and ferrous materials proved to be most efficient in decomposing ammonia at high temperature. Limestone and dolomite did not have any strong catalytic effect on the decomposition of ammonia in the atmospheres studied. The calcareous and ferrous materials can increase the ammonium content of the gas at low temperatures by converting part of the organic nitrogen into ammonia if gas contains high tar loading.