Process For Reducing Fouling In The Processing Of Liquid Hydrocarbons
The present invention relates to the use of a polyester which bears hydroxyl groups and is preparable by polycondensation of a polyol containing two primary OH groups and at least one secondary OH group with a dicarboxylic acid or anhydride thereof or ester thereof bearing a C 16 - to C 400 -alkyl radical or a C 16 - to C 400 -alkenyl radical as an antifoulant in the thermal treatment of liquid hydrocarbon media in the temperature range from 100 to 550 DEG C.
1 . The use of a polyester which bears hydroxyl groups and is preparable by polycondensation of a polyol containing two primary OH groups and at least one secondary OH group with a dicarboxylic acid or anhydride thereof or ester thereof which bears a C 16 - to C 400 -alkyl radical or a C 16 - to C 400 -alkenyl radical as an antifoulant in the thermal treatment of liquid hydrocarbon media within the temperature range from 100 to 550° C.
2 . The use as claimed in claim 1 , wherein the OH number of the polyester is at least 40 mg KOH/g.
3 . The use as claimed in claim 1 and/or 2 , wherein the dicarboxylic acid or anhydride thereof or ester thereof bears a C 16 - to C 40 -alkyl radical or a C 16 - to C 40 -alkenyl radical.
4 . The use as claimed in claim 3 , wherein the dicarboxylic acid is a C 16 - to C 40 -alkyl- or C 16 - to C 40 -alk(en)ylsuccinic acid or anhydride thereof.
5 . The use as claimed in one or more of claims 1 to 4 , wherein the alkyl or alkenyl radical of the dicarboxylic acid or anhydride thereof or ester thereof contains 18 to 36 carbon atoms.
6 . The use as claimed in one or more of claims 3 to 5 , wherein the alkyl or alkenyl radical derives from an α-olefin.
7 . The use as claimed in claim 1 and/or 2 , wherein the dicarboxylic acid or anhydride thereof or ester thereof bears a C 41 - to C 400 -alkyl radical or a C 41 - to C 400 -alkenyl radical.
8 . The use as claimed in claim 7 , wherein the alkyl or alkenyl radical of the dicarboxylic acid is branched.
9 . The use as claimed in claim 7 and/or 8 , wherein the alkyl or alkenyl radical derives from a polyolefin.
10 . The use as claimed in claim 9 , wherein the polyolefin derives from an olefin having 3 to 6 carbon atoms.
11 . The use as claimed in claim 10 , wherein the polyolefin is poly(isobutene).
12 . The use as claimed in one or more of claims 1 to 11 , wherein the polyol is of monomeric structure, and comprises three to 10 carbon atoms and 1 to 6 secondary OH groups, but not more than one OH group per carbon atom.
13 . The use as claimed in one or more of claims 1 to 11 , wherein the polyol is of polymeric structure and comprises six to 150 carbon atoms and two to 50 secondary OH groups, but not more than one OH group per carbon atom.
14 . The use as claimed in one or more of claims 1 to 11 , wherein the polyol is selected from glycerol and oligomers thereof having 2 to 10 monomer units.
15 . The use as claimed in one or more of claims 1 to 14 , wherein the polyester corresponds to the structural formula (A)
in which
one of the R 1 to R 4 radicals is a C 16 -C 400 -alkyl or -alkenyl radical and
the other R 1 to R 4 radicals are each independently hydrogen or an alkyl radical having 1 to 3 carbon atoms,
R 5 is a C—C single bond or an alkylene radical having 1 to 6 carbon atoms,
R 16 is a hydrocarbyl group which bears at least one hydroxyl group and has 3 to 10 carbon atoms,
n is a number from 1 to 100,
m is a number from 3 to 250,
p is 0 or 1, and
q is 0 or 1.
16 . The use as claimed in claim 15 , wherein one of the R 1 to R 4 radicals is a linear C 16 -C 40 -alkyl or -alkenyl radical.
17 . The use as claimed in claim 15 , wherein one of the R 1 to R 4 radicals is a C 41 -C 400 -alkyl or -alkenyl radical.
18 . The use as claimed in claim 9 , wherein R 16 is a radical of the formula (2)
—(CH 2 ) r —(CH(OH)) t —(CH 2 ) s — (2)
in which
t is a number from 1 to 6,
r, s are each independently a number from 1 to 9 and
t+r+s is a number from 3 to 10.
19 . The use as claimed in one or more of claims 1 to 18 , wherein the polyester is nitrogen-free.
20 . The use as claimed in one or more of claims 1 to 19 , wherein the molecular weight of the polyester is between 2000 g/mol and 100 000 g/mol.
21 . The use as claimed in one or more of claims 1 to 20 , wherein the liquid hydrocarbon medium is crude oil or a fraction obtainable from crude oil.
22 . The use as claimed in one or more of, claims 1 to 21 , wherein the liquid hydrocarbon medium is a petrochemical or a hydrocarbon used as a heat carrier.
23 . The use as claimed in one or more of claims 1 to 22 , wherein the liquid hydrocarbon medium is of biogenic origin.
24 . The use as claimed in one or more of claims 1 to 23 , wherein the use is effected at temperatures between 200 and 550° C.
25 . A method for reducing fouling in a liquid hydrocarbon medium during the heat treatment of the medium at temperatures between 100 and 550° C., in which the polyester bearing hydroxyl groups as defined in one or more of claims 1 to 20 is added to the liquid hydrocarbon before and/or during the thermal treatment.
26 . A method for increasing the service life of plants for thermal treatment of hydrocarbons, in which the polyester bearing hydroxyl groups as defined in one or more of claims 1 to 20 is added to the hydrocarbon media to be processed before and/or during the thermal treatment.
27 . The method as claimed in claim 25 or 26 , which proceeds at temperatures of 200 to 550° C.