SNOX process
The SNOX process is a process which removes sulfur dioxide, nitrogen oxides and particulates from flue gases. The sulfur is recovered as concentrated sulfuric acid and the nitrogen oxides are reduced to free nitrogen. The process is based on the well-known wet sulfuric acid process (WSA), a process for recovering sulfur from various process gasses in the form of commercial quality sulfuric acid (H2SO4). The SNOX process is based on catalytic reactions and does not consume water or absorbents. Neither does it produce any waste, except for the separated dust. In addition the process can handle other sulfurous waste streams. This is highly interesting in refineries, where e.g. hydrogen sulfide (H2S) gas, sour water stripper gas and Claus tail gas can be led to the SNOX plant, and thereby investment in other waste gas handling facilities can be saved. Process The SNOX process includes the following steps: Dust removal Catalytic reduction of NOx by adding NH3 to the gas upstream of the SCR DeNOx reactor Catalytic oxidation of SO2 to SO3 in the oxidation reactor Cooling of the gas to about 100 °C whereby the H2SO4 condenses and can be withdrawn as concentrated sulfuric acid Applications The SNOX process developed