Destruction of waste gas
AssigneeThe BOC Group, Inc.
InventorStephen Rhys Graville
Life of this patent
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Abstract
A gas stream containing at least 50% by volume of ammonia but eventually no hydrogen sulphide is burned in a reaction region which is supplied with oxygen and oxygen-enriched air. Both combustion and thermal cracking of ammonia takes place in the reaction region. The rate of supplying oxygen moleculars to the reaction region is from 75 to 98% of the stoichiometric rate required for full combustion of all combustible fluids supplied to the reaction region. Under these conditions essentially no ammonia remains in the effluent gas but formation of oxides of nitrogen can be minimized.
Claims17
A method of destroying a waste gas containing at least 50 percent by volume of ammonia, comprising the steps of:
- (a) supplying at least one stream of the waste gas to a reaction region;
- (b) supplying molecules of oxygen to the reaction region either in at least one stream of oxygen-enriched air or in separate streams of (i) air unenriched in oxygen and (ii) pure oxygen or oxygen-enriched air;
- (c) both burning and thermally cracking ammonia in the reaction region;
- and
- (d) taking from the reaction region an effluent gas stream, comprising nitrogen, water vapour, argon, and hydrogen, but being essentially free of nitric oxide, nitrogen dioxide, and dinitrogen tetroxide and essentially free of ammonia, wherein
- (i) the mole ratio of oxygen molecules to all non-combustible gas molecules (including oxygen molecules) supplied to the reaction region is in the range of 28:100 to 70:100;
- (ii) the rate of supplying oxygen molecules to the reaction region is from 75 to 98% of the stoichiometric rate required for full combustion of all combustible fluids supplied to the reaction region;
- (iii) and essentially no hydrogen sulphide is supplied to the reaction region.
Dependencies are inferred from the claim text.