Integrated processes and systems for conversion of methane to multiple higher hydrocarbon products
Integrated systems are provided for the production of higher hydrocarbon compositions, for example liquid hydrocarbon compositions, from methane using an oxidative coupling of methane system to convert methane to ethylene, followed by conversion of ethylene to selectable higher hydrocarbon products. Integrated systems and processes are provided that process methane through to these higher hydrocarbon products.
1. A method for producing fuel from ethylene produced by oxidative coupling of methane (OCM), the method comprising:
(a) providing an OCM product gas comprising ethylene from an OCM process;
(b) directing a first portion of said OCM product gas into a first ethylene conversion reactor and directing a second portion of said OCM product gas into a second ethylene conversion reactor in parallel to said first ethylene conversion reactor, said first ethylene conversion reactor and said second ethylene conversion reactor operated under different reactor conditions;
(c) in said first ethylene conversion reactor and in said second ethylene conversion reactor, reacting said ethylene from said OCM product gas to produce first higher carbon products and second higher carbon products different from said first higher carbon products, said first higher carbon products and said second higher carbon products including C 3 to C 10 hydrocarbons in separate streams;
(d) combining said separate streams into a product stream, and cooling said product stream in a heat exchanger;
(e) directing said product stream from said heat exchanger into a flash drum that condenses said product stream to produce (i) a light product stream comprising C 2 to C 4 compounds and (ii) a heavy product stream comprising C 4 to C 10 compounds;
(f) directing said light product stream to a compressor that compresses said light product stream; and
(g) directing said light product stream from said compressor to said first ethylene conversion reactor or said second ethylene conversion reactor, thereby (i) reacting at least a portion of said C 2 to C 4 compounds from said light product stream to produce additional said first higher carbon products or second higher carbon products, or (ii) controlling a temperature in said first ethylene conversion reactor or in said second ethylene conversion reactor.
2. The method of claim 1 , wherein said first higher carbon products have a first carbon number range and said second higher carbon products have a second carbon number range different than said first carbon number range.
3. The method of claim 1 , further comprising fractionating said heavy product stream to produce (i) gasoline, (ii) jet fuel, (iii) diesel fuel, (iv) fuel blendstock, or (v) aromatics.
4. The method of claim 3 , further comprising fractionating said heavy product stream to produce at least two of (i)-(v).
5. The method of claim 1 , wherein said first ethylene conversion reactor and said second ethylene conversion reactor each comprises a zeolite catalyst.
6. The method of claim 5 , wherein said zeolite catalyst includes ZSM-5.
7. The method of claim 5 , wherein said first ethylene conversion reactor comprises a different zeolite catalyst than said second ethylene conversion reactor.
8. The method of claim 1 , further comprising directing said heavy product stream into a hydrogenation reactor, and in said hydrogenation reactor hydrogenating said heavy product stream.
9. The method of claim 8 , wherein said heavy product stream is hydrogenated with a Co/Mo, Pd, or Ni/Mo hydrogenation catalyst.
10. The method of claim 9 , wherein olefins in said heavy product stream are hydrogenated to paraffins or isoparaffins in said hydrogenation reactor.
11. The method of claim 1 , wherein said OCM product gas comprises between about 0.5% and about 15% ethylene.
12. The method of claim 1 , wherein said OCM product gas further comprises CO 2 , CO, H 2 , H 2 O, C 2 H 6 , CH 4 , or C 3+ hydrocarbons, or any combination thereof.
13. The method of claim 1 , wherein said OCM product gas further comprises propylene.
14. The method of claim 1 , further comprising cooling said OCM product gas to a temperature between about 200° C. and 500° C. prior to (b).
15. The method of claim 14 , further comprising generating steam from said cooling.
16. The method of claim 1 , further comprising directing a third portion of said OCM product gas into a third ethylene conversion reactor and in said third ethylene conversion reactor, reacting said ethylene from said OCM product gas to produce higher carbon products including C 3 to C 10 compounds.
17. The method of claim 1 , wherein each of said first higher carbon products and said second higher carbon products is generated at a selectivity greater than about 50%.