There are two mainstream denitrification technologies (1) selective catalytic reduction (SCR), (2) selective non-catalytic reduction (SNCR).

The by-product of ammonia desulphurisation is the fertiliser ammonium sulphate, with approximately 4 tonnes of ammonium sulphate being by-produced for every 1 tonne of ammonia, the economics of which depend on the prices of ammonium sulphate and ammonia.

HDS desulphurisation and de-cyanidation technology belongs to wet redox method, which is a desulphurisation method with distinctive features developed by Chengdu Huaxi together with scientific and technological personnel of ammonia and coking industries, and it can make the removal rate of H2S in the gas reach at least 99.9%, and the removal rate of HCN reach more than 97%.