Using a desulfurizer involves employing a specific chemical or physical process to remove sulfur compounds,typically hydrogen sulfide(H2S)or sulfur dioxide(SO2),from a gas or liquid stream.The exact method depends entirely on the application(e.g.,natural gas,refinery products,or power plant flue gas)and the desulfurization agent used.
1.Wet Scrubbing
For large-scale flue gas desulfurization(FGD),wet scrubbing is common.The flue gas passes into a tower where it is contacted with a fine spray or slurry of an alkaline sorbent,most often limestone or lime(CaCO3 or Ca(OH)2).The sorbent reacts chemically with the SO2 to form a solid byproduct like calcium sulfite/sulfate(gypsum),which is then collected and removed.
2.Amine/Chemical Absorption
In natural gas and refinery processes(gas sweetening),a liquid desulfurizer like a tertiary amine(e.g.,MDEA)is circulated through an absorption column.The gas stream flows up,countercurrent to the amine solution,which selectively absorbs the H2S and CO2.The resulting"rich"amine is then sent to a separate regeneration column,where heat is applied to release the acid gases,allowing the"lean"amine to be recycled.
3.Dry/Solid Adsorption
For smaller scale or fine purification,dry desulfurizers like iron oxide(Fe2O3)pellets or activated carbon are used.The gas stream simply passes through a packed bed of this solid material.The sulfur compounds are chemically or physically adsorbed onto the surface of the media.Once saturated,the solid desulfurizer must be either replaced or regenerated,often through steam stripping or an oxidation step.
These processes are critical for meeting environmental regulations and protecting downstream equipment from corrosion.
