Basic ionic liquids as hydrochloric acid scavengers in refinery crude processing
Treatment of crude oil with basic ionic liquids (ILs), results in scavenging of any hydrochloric acid (HCl) that is present to remove the HCl. The IL is a quaternary ammonium compound having the formula R 4 N + X − or R 3 N + R′N + R 3 , where R is independently an alkyl group, an alkylbenzyl group, a hydroxyalkyl group, or a hydroxyalkylbenzyl group, and R is straight or branched and has 1-22 carbon atoms, R′ is a straight or branched alkylene or oxyalkylene having 1 to 10 carbon atoms, and where X − is selected from the group consisting of hydroxide, carbonate, alkylcarbonate, bicarbonate or alkoxide, where the alkyl group of the alkyl-carbonate or alkoxide, if present, is straight or branched and has 1 to 8 carbon atoms. The ILs are introduced into the crude oil after the refinery desalters and before the crude distillation tower to prevent or inhibit HCl from distilling to the crude tower overhead.
1. A method for scavenging hydrochloric acid from crude oil containing the hydrochloric acid, the method comprising:
contacting the crude oil with an amount of a basic ionic liquid effective to react with the hydrochloric acid to scavenge the hydrochloric acid therefrom; where:
the basic ionic liquid consists of:
a quaternary ammonium compound having the formula R 4 N + X − or R 3 N + R′N + R 3 , where:
R is independently an alkyl group, an alkylbenzyl group, a hydroxyalkyl group, or a hydroxyalkylbenzyl group, and R is straight or branched and has 1 to 22 carbon atoms,
R′ is a straight or branched alkylene or oxyalkylene having 1 to 10 carbon atoms, and
where X − is selected from the group consisting of hydroxide, carbonate, alkylcarbonate, bicarbonate or alkoxide, where the alkyl group of the alkylcarbonate or alkoxide, if present, is straight or branched and has 1 to 8 carbon atoms; and
a liquid selected from the group consisting of a monohydric or polyhydric alcohol having 1 to 8 carbon atoms, and an aromatic solvent.
2. The method of claim 1 where contacting the crude oil with the basic ionic liquid is conducted at a temperature between about 240° F. (about 116° C.) to about 750° F. (about 399° C.).
3. The method of claim 1 where contacting the crude oil with the basic ionic liquid is conducted by adding the basic ionic liquid to the crude oil, where the effective amount of the basic ionic liquid ranges from about 1 to about 10 molar equivalents of the basic ionic liquid per molar equivalent of chloride present.
4. The method of claim 1 where in the basic ionic liquid, when X − is carbonate, the carbonate is selected from the group consisting of carbonate, alkylcarbonate, and bicarbonate.
5. A method for scavenging hydrochloric acid from crude oil containing the hydrochloric acid, the method comprising:
contacting the crude oil with an amount of a basic ionic liquid effective to react with the hydrochloric acid to scavenge the hydrochloric acid therefrom; where the contacting is conducted at a location after at least one refinery desalter and before a crude distillation tower at a temperature between about 240° F. (about 116° C.) to about 750° F. (about 399° C.), where:
the basic ionic liquid consists of:
a quaternary ammonium compound having the formula R 4 N + X − or R 3 N + R′N + R 3 , where:
R is independently an alkyl group, an alkylbenzyl group, a hydroxyalkyl group, or a hydroxyalkylbenzyl group, and R is straight or branched and has 1 to 22 carbon atoms,
R′ is a straight or branched alkylene or oxyalkylene having 1 to 10 carbon atoms, and
where X − is selected from the group consisting of hydroxide, carbonate, alkylcarbonate, bicarbonate or alkoxide, where the alkyl group of the alkylcarbonate or alkoxide, if present, is straight or branched and has 1 to 8 carbon atoms; and
a liquid selected from the group consisting of a monohydric or polyhydric alcohol having 1 to 8 carbon atoms, and an aromatic solvent.
6. The method of claim 5 where contacting the crude oil with the basic ionic liquid is conducted by adding the basic ionic liquid to the crude oil, where the effective amount of the basic ionic liquid ranges from about 1 to about 10 molar equivalents of the basic ionic liquid per molar equivalent of chloride present in the crude oil.
7. The method of claim 5 where in the basic ionic liquid, when X − is carbonate, the carbonate is selected from the group consisting of carbonate, alkylcarbonate, and bicarbonate.
8. A method for scavenging hydrochloric acid from crude oil containing the hydrochloric acid, the method comprising:
contacting the crude oil with an amount of a basic ionic liquid effective to react with the hydrochloric acid to scavenge the hydrochloric acid therefrom; where:
the basic ionic liquid consists of:
a quaternary ammonium compound having the formula R 4 N + X − or R 3 N + R′N + R 3 , where:
R is independently an alkyl group, an alkylbenzyl group, a hydroxyalkyl group, or a hydroxyalkylbenzyl group, and R is straight or branched and has 1 to 22 carbon atoms,
R′ is a straight or branched alkylene or oxyalkylene having 1 to 10 carbon atoms, and
where X − is selected from the group consisting of hydroxide, carbonate, alkylcarbonate, bicarbonate or alkoxide, where the alkyl group of the alkylcarbonate or alkoxide, if present, is straight or branched and has 1 to 8 carbon atoms;
the basic ionic liquid further comprises a liquid selected from the group consisting of water, a monohydric or polyhydric alcohol having 1 to 8 carbon atoms, and an aromatic solvent; and
contacting the crude oil with the basic ionic liquid is conducted by adding the basic ionic liquid to the crude oil, where the effective amount of the basic ionic liquid ranges from about 1 to about 10 molar equivalents of the basic ionic liquid per molar equivalent of chloride present.
9. The method of claim 8 where contacting the crude oil with the basic ionic liquid is conducted at a temperature between about 240° F. (about 116° C.) to about 750° F. (about 399° C.).
10. The method of claim 8 where in the basic ionic liquid, when X − is carbonate, the carbonate is selected from the group consisting of carbonate, alkylcarbonate, and bicarbonate.
11. The method of claim 1 further comprising, prior to the contacting, forming the hydrochloric acid by hydrolysis of a chloride selected from the group consisting of organic chlorides and inorganic chlorides.
12. The method of claim 11 further comprising, prior to the contacting, forming the hydrochloric acid by hydrolysis of a chloride selected from the group consisting of magnesium chloride and calcium chloride.