Ethylene-to-liquids systems and methods
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, comprising:
(a) directing an olefin feed stream comprising (i) ethylene (C 2 H 4 ) at a concentration of at least about 0.5 mole percent (mol %), (ii) propylene (C 3 H 6 ) and (iii) carbon monoxide (CO) or carbon dioxide (CO 2 ), into an ethylene-to-liquids (ETL) reactor, wherein said ETL reactor comprises an ETL catalyst that facilitates conversion of C 2 H 4 to higher hydrocarbon products, wherein said ETL reactor operates substantially adiabatically, wherein said olefin feed stream has a combined concentration of C 2 H 4 and C 3 H 6 of at most about 10 mol %, and wherein said olefin feed stream is at a first temperature;
(b) in said ETL reactor, conducting an ETL process to convert said C 2 H 4 in said olefin feed stream to said higher hydrocarbon products as part of a product stream at a second temperature, said higher hydrocarbon products including (i) at least 5 compounds having 5 different carbon numbers, said 5 carbon numbers selected from 12 through 20 and (ii) a paraffin compound, an isoparaffin compound, and a naphthene compound, which second temperature is higher than said first temperature, and wherein said ETL process liberates heat; and
(c) recovering from said product stream a liquid stream comprising said higher hydrocarbon products including (i) at least 5 compounds having 5 different carbon numbers, said 5 carbon numbers selected from 12 through 20, wherein each of said 5 carbon numbers is at a concentration of at least 5 weight percent (wt %) of said liquid stream, and (ii) a paraffin compound, an isoparaffin compound, and a naphthene compound,
wherein at least about 80% of said heat liberated in said ETL process provides a difference between said first temperature and said second temperature of between about 50° C. and about 150° C.
2. The method of claim 1 , wherein said higher hydrocarbon products further comprise an olefin compound or an aromatic compound.
3. The method of claim 1 , wherein said recovering comprises cooling said product stream.
4. The method of claim 1 , further comprising, prior to (a), directing said olefin feed stream into a treatment unit, and in said treatment unit reducing the concentration in said olefin feed stream of (1) compounds having triple bonds or (2) compounds having more than one double bond, wherein said reducing is accomplished by a separations process or a reaction process.
5. The method of claim 1 , wherein said olefin feed stream comprises less than about 500 parts per million (ppm) of acetylene.
6. The method of claim 1 , further comprising, prior to (a), directing said olefin feed stream into a treatment unit, and in said treatment unit reducing the concentration in said olefin feed stream of compounds having sulfur to less than about 300 parts per million (ppm).
7. The method of claim 1 , wherein said olefin feed stream comprises less than about 10 mol % carbon monoxide (CO).
8. The method of claim 1 , wherein said higher hydrocarbon products are generated at a single pass conversion of at least about 40%.
9. The method of claim 1 , wherein said ETL reactor is operated at a temperature greater than or equal to about 200° C.
10. The method of claim 1 , wherein said ETL reactor is operated at a pressure greater than or equal to about 50 pounds per square inch.
11. The method of claim 1 , wherein said product stream comprises less than about 50 weight percent (wt %) water.