Flexible production of benzene and derivatives thereof via oligomerization of ethylene
Disclosed is oligomerization of ethylene to form 1-hexene in combination with aromatization of the 1-hexene formed by oligomerization, to form benzene.
1 . A method comprising:
contacting, in an oligomerization reactor, ethylene and an oligomerization catalyst to yield an oligomerization reactor effluent comprising 1-hexene;
flowing at least a portion of 1-hexene recovered from the oligomerization reactor effluent to a hydrogenation reactor;
contacting, in the hydrogenation reactor, the at least a portion of 1-hexene with a hydrogenation catalyst to yield a hydrogenation reactor effluent comprising hexanes;
recovering hexanes from the hydrogenation reactor effluent; and
contacting, in an aromatization reactor, hexanes recovered from the hydrogenation reactor effluent with an aromatization catalyst to yield an aromatization reactor effluent comprising benzene.
2 . The method of claim 1 , further comprising:
cracking ethane, propane, butane, pentane, naphtha, or mixtures thereof in a steam cracker to yield a cracker effluent comprising ethylene; and
flowing ethylene recovered from the cracker effluent to the oligomerization reactor.
3 . The method of claim 2 , further comprising:
recovering light hydrocarbons from the cracker effluent; and
using the light hydrocarbons recovered from the cracker effluent for cooling for an oligomerization process containing the oligomerization reactor or for an aromatization process containing the aromatization reactor.
4 . The method of claim 2 , further comprising:
recovering steam from the steam cracker; and
using the steam recovered from the steam cracker in an oligomerization process containing the oligomerization reactor.
5 . The method of claim 2 , further comprising:
flowing ethylene recovered from the cracker effluent to an alkylation reactor;
flowing benzene recovered from the aromatization reactor effluent to the alkylation reactor; and
contacting, in the alkylation reactor, the ethylene recovered from the cracker effluent and the benzene recovered from the aromatization reactor effluent with an alkylation catalyst to yield an alkylation reactor effluent comprising ethylbenzene.
6 . The method of claim 5 , further comprising:
flowing ethylbenzene recovered from the alkylation reactor effluent to a dehydrogenation reactor; and
contacting, in the dehydrogenation reactor, ethylbenzene with a dehydrogenation catalyst to yield a dehydrogenation reactor effluent comprising styrene.
7 . The method of claim 1 , wherein contacting ethylene and the oligomerization catalyst is performed in a presence of a diluent i) selected from isobutane, cyclohexane, methylcyclohexane, n-alkanes, branched alkanes, iso-paraffin solvents, 2,2,4-trimethylpentane, or combinations thereof, or ii) recovered from the aromatization reactor effluent, wherein the diluent is selected from a raffinate, benzene, toluene, xylene, branched alkanes, or a combination thereof.
8 . The method of claim 1 , wherein the 1-hexene is recovered from the oligomerization reactor effluent by washing to remove catalyst and fractionation to remove diluent.
9 . The method of claim 1 , further comprising:
contacting, in the hydrogenation reactor, benzene recovered from the aromatization reactor effluent with the hydrogenation catalyst to yield cyclohexane in the hydrogenation reactor effluent;
recovering the cyclohexane from the hydrogenation reactor effluent; and
recycling the cyclohexane recovered from the hydrogenation reactor effluent to the oligomerization reactor.
10 . The method of claim 1 , further comprising:
recovering a lower purity 1-hexene stream from the oligomerization reactor effluent;
recovering a higher purity 1-hexene stream from the lower purity 1-hexene stream; and
flowing a portion of the lower purity 1-hexene stream to the hydrogenation reactor.
11 . The method of claim 1 , wherein a sulfur removal system is not used in flowing 1-hexene recovered from the oligomerization reactor effluent to the aromatization reactor.
12 . The method of claim 1 , wherein the oligomerization reactor effluent further comprises heavy hydrocarbons having greater than 8 carbon atoms, the method further comprising:
flowing the heavy hydrocarbons recovered from the oligomerization reactor effluent to a steam cracker; and
cracking the heavy hydrocarbons in the steam cracker.
13 . The method of claim 1 , further comprising:
flowing a raffinate recovered from the aromatization reactor effluent to a steam cracker; and
cracking the raffinate in the steam cracker.
14 . The method of claim 1 , wherein the oligomerization reactor effluent further comprises a heavy hydrocarbon having greater than 8 carbon atoms, the method further comprising:
blending the heavy hydrocarbon, a raffinate obtained from the aromatization reactor effluent, or both the heavy hydrocarbon and the raffinate into a motor fuel stream.
15 . The method of claim 1 , further comprising:
flowing hydrogen and light hydrocarbons having less than 6 carbon atoms recovered from the aromatization reactor effluent to a demethanizer, a depropanizer, or both a demethanizer and a depropanizer.
16 . A system comprising:
an oligomerization reactor configured to contact ethylene with an oligomerization catalyst to yield an oligomerization reactor effluent comprising 1-hexene;
a hydrogenation reactor configured to contact 1-hexene recovered from the oligomerization reactor effluent with a hydrogenation catalyst to yield an aromatization feed comprising hexane; and
an aromatization reactor configured to contact the aromatization feed with an aromatization catalyst to yield an aromatization reactor effluent comprising benzene.
17 . The system of claim 16 , further comprising:
a steam cracker that cracks ethane, propane, butane, pentane, naphtha, or mixtures thereof to yield a cracker effluent comprising ethylene,
wherein the oligomerization reactor receives at least a portion of the ethylene.
18 . The system of claim 17 , further comprising:
an alkylation reactor that receives at least a portion of the ethylene from the cracker effluent and at least a portion of the benzene from the aromatization reactor effluent, wherein the alkylation reactor is configured to contact the ethylene received from the cracker effluent and the benzene received from the aromatization reactor effluent with an alkylation catalyst to yield an alkylation reactor effluent comprising ethylbenzene.
19 . The system of claim 18 , further comprising:
a dehydrogenation reactor that receives at least a portion of the ethylbenzene from the alkylation reactor effluent, wherein the dehydrogenation reactor is configured to contact the at least a portion of the ethylbenzene with a dehydrogenation catalyst to yield a dehydrogenation reactor effluent comprising styrene.