WSA – can it make your TGTU viable?
For industries like oil refining, coal gasification and coking, the WSA (Wet gas Sulfuric Acid) Technology has been the preferred acid gas treatment solution for decades.
The WSA process is a simple and efficient sulfur recovery process meeting the demands of the industry for environmental compliance without tail-gas treatment, low energy usage, and low overall operating costs. Sulfur in any form is recovered as concentrated sulfuric acid of commercial quality.
The ratio between H2S and CO2 is important for the acid gas treatment. In case of a low ratio, below say 20 vol.-% H2S, a Claus plant is difficult to operate. By selecting the WSA process, there is no such thing as difficult acid gas – the WSA plant can treat H2S concentrations ranging from 1 vol% to 100 vol%. In this way you can avoid using special amines and enrichment units. Also a TGTU and a thermal oxidizer can be omitted and thereby the CAPEX drastically reduced.
In addition, producing sulfuric acid liberates three times as much energy than producing elemental sulfur from H2S. The additional energy in the form of high pressure steam is highly appreciated for amine regeneration, or for power generation.
Today, more than 150 plants worldwide benefit from a licensed Topsoe WSA plant tailored for various applications and ranging from 2 to 300 tpd sulfur equivalents.
The paper describes the WSA technology, how it is applied in the gas treatment sector and shows a case story from an LNG plant in Indonesia. Also a comparison with the Claus technology is given.
