Patent CA-1270746-A (CA)
Inventor: GAZZI LUIGI
IPC: C10K1/16
Filed: 1986-05-22
Granted: 1990-06-26
Abstract: "CRYOGENIC  PROCESS FOR THE SELECTIVE REMOVAL  OF  ACIDIC GASES FROM MIXTURES OF GASES BY SOLVENTS"               Abstract of the Disclosure A  cryogenic process is disclosed for the  selective removal  of acidic gases from natural gases or from syn-thesis  gases by adsorption in two towers and cooling  of the gas outcoming from the first tower to the purpose  of condensing  a  portion of CO2 contained in the same  gas, which  is characterized in that in it a mixture  is  used constituted  by  one or more selective solvents  selected among low molecular weight esters, alcohols and ethers of the following classes: - esters of alcohols of general formula R1COOR2, wherein  R1  and  R2 are alkyl groups of from  1  to  4 carbon  atoms,  equal to or different from each  other, wherein  one or more hydrogen atoms can be  substituted by alcoholic groups; - esters of glycols of general formula   or 2.    wherein  R1 and R2 are alkyl groups having from 1 to  3 carbon  atoms,  equal to or different from each  other, R3,  R4, R5, R6, equal to or different from each other, are  either alkyl groups containing from 1 to 3  carbon atoms or hydrogen atoms, m and n are integers which can have the value 0 or 1; - cyclic esters (lactones) of formula   or   wherein R2, R3, R4, R5, equal to or different from each other, are alkylene groups wherein one or more hydrogen atoms can also be substituted by alkylic,  alcoholic or ether groups; - alcohols of general formula   wherein R1,  R2,  R3, R4, R5, R6, equal to or different from  each other,  are alkyl groups having from 1 to  3 carbon atoms or hydroxy groups or hydrogen atoms, m and 3. n are integers which can assume the values O and 1; - cyclic ethers such as   wherein  R2,  R5,  R6,  equal to or different from each other,  are  alkyl groups wherein hydrogen can also  be substituted by alkyl or methoxy groups, R3 is either an oxygen  atom or an alkylene group wherein hydrogen  can also be substituted by alkyl or methoxy groups,  R4  is either   equal  to  R3 or can be absent in  case  of  a pentaatomic ring; - ethers of general formula R1-O-CH2-(R3)n-CH2-O-R2 wherein  R1  is an alkyl group of from 1  to  4  carbon atoms,  R2  is  either  an alkyl group of from 1  to 4 carbon  atoms  or a hydrogen atom ,  R3  is  either  an alkylene  group or (CH2-0-CH2),  n is an integer  which can have the value 0 or 1; - ethers of general formula wherein  R1 and R2,  either equal to or different  from each  other,  are  alkyl groups of from 1 to  4  carbon atoms,  wherein  one or more hydrogen atoms can be sub-stituted by alcoholic groups; - ester-ethers,  compounds containing both the functions, of formula:            (R4-0)n - R1 - COOR2 (OR3)m wherein  R3  and R4,  equal to or different  from  each other,  are  alkyl  groups having from 1  to  4 carbon 4. atoms,  R2  is  an  alkylene group having from 1  to 4 carbon atoms,  R1 is either equal to R2 or equal to R3, m and D are integers which can have the value 0 or 1, and by one or more organic compounds selected from: - heptane, - fractions  of natural gasolines containing hydrocarbons having  a number of carbon atoms comprised  within  the range of from 5 to 8; - monoaromatic  compounds  having a number of  paraffinic carbon atoms comprised within the range of from 2 to 4, bound  to the benzene ring either separately or as  one or more linear or branched side chains; - dimethylethers  of polyglycols having the glycolic unit -CH2-CH-O- repeated from once to five times; - methoxy- and/or  ethoxyalcohols,  wherein the alcoholic group  is a radical having from 1 to 4 carbon atoms  in either linear or branched chain.