Systems and processes for conversion of ethylene feedstocks to hydrocarbon fuels
Systems, processes, and catalysts are disclosed for obtaining fuel and fuel blends containing selected ratios of open-chain and closed-chain fuel-range hydrocarbons suitable for production of alternate fuels including gasolines, jet fuels, and diesel fuels. Fuel-range hydrocarbons may be derived from ethylene-containing feedstocks and ethanol-containing feedstocks.
1. A process for conversion of an ethylene-containing feedstock into distillate range hydrocarbons for fuels and fuel blend stocks, the method comprising the steps of:
oligomerizing ethylene in the ethylene-containing feedstock over a metal heterogeneous catalyst at a temperature from about 40° C. to 200° C. to form a water-free first oligomerization product in a first reaction stage, wherein the first oligomerization product contains a majority concentration of mixed olefins with a carbon number from about C4 to about C8; and
oligomerizing the mixed olefins in the water-free first oligomerization product over a non-metal heterogeneous catalyst at a temperature from greater than 200° C. to about 350° C. to form a second oligomerization product in a subsequent reaction stage, wherein the second oligomerization product contains mixed linear olefins and branched olefins with a carbon number from about C8 to about C23 in a yield of greater than or equal to 20% suitable for production of selected hydrocarbon fuels and fuel blend stocks.
2. The process of claim 1 , wherein the ethylene-containing feedstock is derived from ethanol.
3. The process of claim 1 , wherein the ethylene-containing feedstock is derived from methanol.
4. The process of claim 1 , wherein the yield of mixed linear olefins and branched olefins with a carbon number greater than or equal to C8 in the second oligomerization product is greater than or equal to about 50%.
5. The process of claim 1 , wherein the yield of mixed linear olefins and branched olefins with a carbon number ranging from greater than or equal to C8 to C23 in the second oligomerization product is greater than or equal to about 70%.
6. The process of claim 1 , wherein the second oligomerization product includes a concentration of open-chain oligomers greater than or equal to about 90% by weight.
7. The process of claim 1 , wherein the second oligomerization product includes a concentration of aromatic compounds less than or equal to about 4% by weight.
8. The process of claim 1 , wherein the second oligomerization product includes a concentration of aromatic compounds ranging from about 4% to about 20% by weight.
9. The process of claim 1 , wherein the second oligomerization product includes a concentration of aromatic compounds greater than or equal to about 20% by weight.
10. The process of claim 1 , further including fractionating the second oligomerization product to obtain individual fractions, a fraction containing distillate range olefins with a carbon number greater than or equal to about C8, and a light fraction containing olefins with a carbon number less than or equal to about C8.
11. The process of claim 10 , wherein the distillate-range olefin fraction is hydrotreated to yield a mixture of linear and branched paraffins and iso-paraffins a majority boiling from about 120° C. to about 300° C.
12. The process of claim 10 , wherein the distillate-range olefin fractions include open chain linear and branched hydrocarbons with a carbon number from about C8 to about C16.
13. The process of claim 12 , wherein the about C8 to about C16 fraction is hydrotreated to form linear and branched paraffins and iso-paraffins in the jet fuel range.
14. The process of claim 12 , wherein the about C8 to about C16 fraction is hydrotreated to form a mixture boiling from about 120° C. to about 300° C.
15. The process of claim 1 , further including fractionating the second oligomerization product to obtain individual fractions, a fraction containing distillate range olefins with a carbon number greater than or equal to about C11, and a light fraction containing olefins with a carbon number less than or equal to about C11.
16. The process of claim 15 , wherein the distillate-range olefin fraction is hydrotreated to yield a mixture of linear and branched paraffins and iso-paraffins a majority boiling from about 160° C. to about 390° C.
17. The process of claim 15 , wherein the distillate-range olefin fractions include open chain linear and branched hydrocarbons with a carbon number from about C11 to about C23.
18. The process of claim 17 , wherein the about C11 to about C23 fraction is hydrotreated to form linear and branched paraffins and iso-paraffins in the diesel fuel range.
19. The process of claim 17 , wherein the about C11 to about C23 fraction is hydrotreated to form a mixture boiling from about 160° C. to about 390° C.
20. The process of claim 1 , further including fractionating the second oligomerization product to obtain individual fractions, a fraction containing distillate range olefins boiling higher than about 120° C., and a light fraction boiling below about 120° C.
21. The process of claim 20 , wherein the distillate-range olefin fraction is hydrotreated to yield open-chain linear and branched paraffins and iso-paraffins.
22. The process of claim 21 , wherein the open chain linear and branched paraffins and iso-paraffins are used as components of a fuel production process or a fuel blending process.
23. The process of claim 21 , wherein the open chain linear and branched paraffins and iso-paraffins contain a fraction with a boiling range of about 120° C. to about 300° C.
24. The process of claim 21 , wherein the open-chain linear and branched paraffins and iso-paraffins boil in the jet fuel range.
25. The process of claim 20 , further including hydrotreating the light fraction to form open-chain linear and branched paraffins and iso-paraffins that boil in the gasoline fuel range.
26. The process of claim 20 , further including recycling the light fraction over the non-metal heterogeneous catalyst to increase the yield of second oligomerization product having a boiling range of about 120° C. to about 300° C.
27. The process of claim 26 , wherein the recycling includes mixing the light fraction with the water-free first oligomerization product to make a new mixture, the new mixture being oligomerized over the non-metal heterogeneous catalyst to increase the yield of second oligomerization product having a boiling range of about 120° C. to about 300° C.
28. The process of claim 1 , further including fractionating the second oligomerization product to obtain individual fractions, a fraction containing distillate range olefins boiling higher than about 160° C., and a light fraction boiling below about 160° C.
29. The process of claim 28 , wherein the distillate-range olefin fraction is hydrotreated to yield open-chain linear and branched paraffins and iso-paraffins.
30. The process of claim 29 , wherein the open chain linear and branched paraffins and iso-paraffins are used as components of a fuel production process or a fuel blending process.
31. The process of claim 29 , wherein the open chain linear and branched paraffins and iso-paraffins contain a fraction with a boiling range of about 160° C. to about 390° C.
32. The process of claim 29 , wherein the open-chain linear and branched paraffins and iso-paraffins boil in the diesel fuel range.
33. The process of claim 28 , further including hydrotreating the light fraction to form open-chain linear and branched paraffins and iso-paraffins that boil in the gasoline fuel range.
34. The process of claim 28 , further including recycling the light fraction over the non-metal heterogeneous catalyst to increase the yield of second oligomerization product having a boiling range of about 160° C. to about 390° C.
35. The process of claim 34 , wherein the recycling includes mixing the light fraction with the water-free first oligomerization product to make a new mixture, the new mixture being oligomerized over the non-metal heterogeneous catalyst to increase the yield of second oligomerization product having a boiling range of about 160° C. to about 390° C.
36. The process of claim 1 , wherein the metal heterogeneous catalyst comprises nickel (Ni) on a silico-aluminate support with a nickel concentration of from about 0.2% to about 5% by weight.
37. The process of claim 1 , wherein the metal heterogeneous catalyst comprises a crystalline zeolite support selected from Y zeolites, Beta zeolites, HZSM-5 zeolites, Mordenite zeolites, Ferrierite zeolites, Al-MCM-41 zeolites, MCM-48 zeolites, MCM-22 zeolites, SAPO-34 zeolites, Chabazite zeolites, Group I metal-exchanged zeolites, Group II metal-exchanged zeolites, and combinations thereof.
38. The process of claim 1 , wherein the metal heterogeneous catalyst comprises an amorphous silicoaluminate support selected from Grace 3111, Grace 3113, Grace 3115, Grace 3125, and Grace X501, Group I metal-exchanged amorphous silicoaluminates, Group II metal-exchanged amorphous silicoaluminates, and combinations thereof.
39. The process of claim 1 , wherein the non-metal heterogeneous catalyst is a solid acid catalyst.
40. The process of claim 1 , wherein the non-metal heterogeneous catalyst is a crystalline zeolite catalyst selected from Y zeolites, Beta zeolites, HZSM-5 zeolites, Mordenite zeolites, Ferrierite zeolites, Al-MCM-41 zeolites, MCM-48 zeolites, MCM-22 zeolites, SAPO-34 zeolites, Chabazite zeolites, hydrogen-exchanged zeolite catalysts, and combinations thereof.
41. The process of claim 1 , wherein the non-metal heterogeneous catalyst is an amorphous silicoaluminate catalyst selected from Grace 3111, Grace 3113, Grace 3125, and Grace X501, Amberlyst 70, and combinations thereof.
42. A system for conversion of an ethylene-containing feedstock into distillate range hydrocarbons for fuels and fuel blend stocks, the system comprising:
a first reactor or reactor stage optionally pressurized with an inert gas and that contains a supported metal catalyst comprising nickel (Ni) on a solid silicoaluminate support configured to oligomerize ethylene in the feedstock introduced thereto at a temperature from about 40° C. to 220° C. and pressure selected to produce a first oligomerization product containing a majority concentration of mixed olefins with a carbon number in the range from about C4 to about C8; and
a second reactor or reactor stage, optionally pressurized with an inert gas, and that contains a solid acid catalyst that converts olefins in the first oligomerization product from the first reactor and forms a second oligomerization product containing linear olefins and branched olefins with a carbon number from about C8 to about C23 in a yield of greater than or equal to 20% suitable for production of selected hydrocarbon fuels and fuel blend stocks.
43. The system of claim 42 , wherein the first reactor or reactor stage employs a temperature below 220° C. and a total pressure selected in the range from about 100 psig to about 1200 psig.
44. The system of claim 42 , wherein the second reactor or reactor stage employs a temperature from about 150° C. to about 350° C. and a total pressure selected in the range from about 50 psig to about 1000 psig.