mahmood sahabi - M.Sc student faculty of chemical engineering
mansoor shirvani - assistant professor
hooman fatoorehchi - M.Sc student faculty of chemical engineering

the fact that liquefaction of natural gas occurs at an extremely low temperature -160c which is times lesser than the freezing point of carbon dioxide -60 c imposes a more CO2 removal/ separation in LNG production process compared to the degree needed for ordinary pipiline gas transporation. in order words , if carbon dioxide component of natural gas is not lowered down to at least 50ppmv during LNG production , it will freeze and stop the system from funcioning . because of some other essential requirements , a limited numbers of sweetening methods like sulfionl and activated methyl diethanolamine aMDEA are being used in LNG units wordwide. acoordingly in this paper the intrinsic properties /characteristics of a gas sweetening suitable for LNG units is described and the methods in this service worldwide are discussed in detail. in the end the plus points and drawbacks of each method are investigated.

LNG, carbon dioxide, sulfinol, Amdea