Desulphurisation with zero waste
Several options are available to remove SO2 and byproducts from in gases. Our expertise goes from sulphuric acid plant tail gas, to refinery and secondary hood in gases from metal smelters.
Simply removing SO2 with caustic will create a large amount of waste water, partly in the form of Sulphites, which have to be oxidized before entering the waste water cleaning. See image 1
Ecosystems has supplied all kind of processes alternative to caustic. The design of recent project was awarded to us by Tata Steel where we transform the SO2 into ammonium sulphate, in a useful product for the fertiliser industry.
The gases pass through two columns with different pH in order to concentrate the ammonium sulphate to 38 weight% in the liquid. Advantage is savings on energy cost down stream when the ammonium sulphate is solidified to dry fertiliser.
Special care is taken by installing a high efficient mist eliminator to remove solid submicron ammonium sulphate and H2SO4 mist. See image 2
Ecosystems has several units in operation based on this principle please inquire. See image 3
Other options for zinc smelters include Gas Scrubbers with addition of zinc oxide. In this case the produced zinc sulphate is send back to the feed stock of the furnace. See image 4
More common is the use of peroxide for tail gas of sulphuric acid plants. In these we can produce sulphuric acid up to a concentration of 40%. The effluent can be reused in the acid plant to be concentrated to 98%. See image 5
Image 1 - Caustic tail gas scrubber
Image 3 - Amsox tail gas scrubber The Netherlands
Image 5 - Peroxide can produce weak acid for reuse