Demulsifiers
The present invention provides a demulsifier comprising a compound of the general formula (I), a demulsification formulation comprising the demulsifier, methods of making a demulsifier, a method of demulsifying an oil-in-water or a water-in oil emulsion and the use as a demulsifier of a compound comprising a dimer and/or trimer fatty residue and an alkyleneoxy chain comprising a first ethyleneoxy section, a second ethyleneoxy section, and a propyleneoxy section located between the first ethyleneoxy section and the second ethyleneoxy section, wherein the propyleneoxy section comprises from 1 to 20 propyleneoxy groups. The demulsifier may be for use in demulsifying an emulsion, for example crude oil.
1. A compound of the general formula (I):
R 1 [(EO) p (PO) q (EO) r R 2 ]n (I)
where:
R 1 comprises a mixture of dimer fatty residues and trimer fatty residues and the weight ratio of dimer fatty residues to trimer fatty residues is from 20 to 0.2:1;
R 2 is H or (CO) x R 3 where x is 0 or 1 and R 3 is a C 1 to C 6 aliphatic hydrocarbyl group;
EO is an ethyleneoxy group;
PO is a propyleneoxy group;
p is from 1 to 20;
q is from 1 to 20;
r is from 1 to 20; and
n is from 1 to 3.
2. A compound as claimed in claim 1 wherein p is from 3 to 15.
3. A compound as claimed in claim 1 wherein q is from 3 to 15.
4. A compound as claimed in claim 1 wherein r is from 3 to 15.
5. A compound as claimed in claim 1 wherein the ratio of (p+r) to q is from 0.5 to 8:1.
6. A compound as claimed in claim 1 wherein the ratio of p to q to r is from 0.5 to 2:from 0.5 to 2:from 0.5 to 2.
7. A compound as claimed in claim 1 wherein of the mixture of dimer fatty residues and trimer fatty residues comprises at least one of: a dimer fatty diacid having from 24 to 48 carbon atoms, a trimer fatty triacid having from 36 to 72 carbon atoms, a dimer fatty diol having from 24 to 48 carbon atoms and/or a trimer fatty triol having from 36 to 72 carbon atoms.
8. A compound as claimed in claim 1 wherein the mixture of dimer fatty residues and trimer fatty residues comprises a mixture of dimer fatty diacid residues and trimer fatty triacid residues and the weight ratio of dimer fatty diacid to trimer fatty triacid is from 20 to 0.2:1.
9. A compound as claimed in claim 1 wherein R 2 is H.
10. A compound as claimed in claim 1 wherein the compound of general formula (I) has a viscosity at 25° C. of 500 cP to 15,000 cP.
11. A compound as claimed in claim 1 wherein the compound of general formula (I) has a pour point of −45° C. to +30° C.
12. A demulsification formulation comprising 0.1 to 80 wt % of a compound as claimed in claim 1 .
13. A method of making a compound comprising the steps of:
a) forming an alkyleneoxy chain of the general formula (II):
HO(EO) p (PO) q (EO) r H (II)
where:
EO is an ethyleneoxy group;
PO is a propyleneoxy group;
p is from 1 to 20;
q is from 1 to 20; and
r is from 1 to 20; and
b) reacting the alkyleneoxy chain with a mixture of a dimer fatty diacid, and a trimer fatty triacid, wherein the weight ratio of dimer fatty diacid to trimer fatty triacid is from 20 to 0.2:1.
14. A method of making a compound comprising the steps of:
a) reacting a mixture of a dimer fatty diacid and a trimer fatty triacid with 2 to 60 mols of ethylene oxide, wherein the weight ratio of dimer fatty diacid to trimer fatty triacid is from 20 to 0.2:1;
b) reacting the product of step a) with 2 to 60 mols of propylene oxide; and
c) reacting the product of step b) with 2 to 60 mols of ethylene oxide.
15. A method as claimed in claim 14 wherein the compound is a compound of general formula (I):
R 1 [(EO) p (PO) q (EO) r R 2 ] n (I)
where:
R 1 comprises a mixture of residues of the dimer fatty diacid and the trimer fatty triacid, wherein the weight ratio of dimer fatty diacid to trimer fatty triacid is from 20 to 0.2:1;
R 2 is H;
EO is an ethyleneoxy group;
PO is a propyleneoxy group;
p is from 2 to 20;
q is from 2 to 20;
r is from 2 to 20; and
n is from 1 to 3.
16. A method of demulsifying an oil-in-water or a water-in-oil emulsion comprising the step of adding a compound as claimed in claim 1 to the emulsion.
17. A method as claimed in claim 16 wherein the emulsion comprises crude oil.