초록 ▼

The present invention relates to the selective separation of methane (“CH4”) from higher carbon number hydrocarbons (“HHC”s) in streams containing both methane and higher carbon number hydrocarbons (e.g. ethylene, ethane, propylene, propane, etc.) utilizing a zeolitic imidazolate framework (“ZIF”) m

The present invention relates to the selective separation of methane (“CH4”) from higher carbon number hydrocarbons (“HHC”s) in streams containing both methane and higher carbon number hydrocarbons (e.g. ethylene, ethane, propylene, propane, etc.) utilizing a zeolitic imidazolate framework (“ZIF”) material. Preferably, the stream to be separated is fed to the present process in a substantially gaseous phase. In preferred embodiments, the current invention is utilized in a process to separate methane from higher carbon number hydrocarbons in natural gas streams.

대표청구항 ▼

1. A process for separating CH4 from a process feedstream, comprising: a) contacting an adsorbent material comprised of a zeolitic imidazolate framework material with a process feedstream comprising CH4 and at least one C2+ hydrocarbon compound at a first pressure and first temperature;b) adsorbing

1. A process for separating CH4 from a process feedstream, comprising: a) contacting an adsorbent material comprised of a zeolitic imidazolate framework material with a process feedstream comprising CH4 and at least one C2+ hydrocarbon compound at a first pressure and first temperature;b) adsorbing at least a portion of the C2+ hydrocarbon compound in the adsorbent material, thereby producing a CH4-rich product stream, wherein the CH4-rich product stream has a higher concentration of CH4 by mol % than the process feedstream; andc) producing a CH4-lean product stream at a second pressure and second temperature, wherein the CH4-lean product stream has a lower concentration of CH4 by mol % than the process feedstream;wherein the zeolitic imidazolate framework material has a framework structure wherein each vertex of the framework structure is comprised of a single metal ion and each pair of connected adjacent vertices of the framework structure is linked by nitrogen atoms of an imidazolate anion or its derivative, and wherein the zeolitic imidazolate framework material has an adsorptive loading ratio measured at 301 K and 106.6 kPa for the C2+ hydrocarbon compound over CH4 of at least 5. 2. The process of claim 1, wherein the adsorbent material is further comprised of a binder material selected from the group consisting of a crystalline polymer, a non-crystalline polymer, an epoxy, a thermoplastic, a clay, a silica-containing material, an alumina-containing material, and a titania-containing material. 3. The process of claim 1, wherein the zeolitic imidazolate framework material is selected from the group consisting of ZIF-7, ZIF-9, and ZIF-1. 4. The process of claim 3, wherein the CH4-rich product stream contains at least 70 mol % of the CH4 present in the process feedstream. 5. The process of claim 4, wherein the C2+ hydrocarbon compound partial pressure in step a) is greater than the C2+ hydrocarbon compound partial pressure in step d). 6. The process of claim 5, wherein the first pressure is greater than the second pressure. 7. The process of claim 5, wherein the second temperature is greater than the first temperature. 8. The process of claim 5, wherein the process is a swing adsorption process, wherein the overall swing adsorption cycle time is less than about 1 minute. 9. The process of claim 5, wherein the process is a swing adsorption process and the difference between maximum and minimum C2+ hydrocarbon compound partial pressures achieved in the adsorbent bed during a cycle is less than 43.5 psia (300 kPaa). 10. The process of claim 5, wherein the C2+ hydrocarbon compound has a partial pressure in the process feedstream in step a) of less than about 29 psia (200 kPaa). 11. The process of claim 1, wherein the process feedstream is comprised of a natural gas. 12. The process of claim 11, wherein at least a portion of the CH4-rich product stream is utilized to make a final natural gas product. 13. The process of claim 11, wherein the first pressure is at least 500 psig. 14. The process of claim 11, wherein the zeolitic imidazolate framework material is selected from the group consisting of ZIF-7, ZIF-9, and ZIF-1. 15. The process of claim 14, wherein the CH4-rich product stream contains at least 70 mol % of the CH4 present in the process feedstream. 16. The process of claim 1, wherein the C2+ hydrocarbon compound is selected from the group consisting of C2H4 (ethylene), C2H6 (ethane), C3H6 (propylene), C3H8 (propane), C4H8 (1-butene), and C4H10 (n-butane). 17. The process of claim 16, wherein the zeolitic imidazolate framework material is selected from the group consisting of ZIF-7, ZIF-9, and ZIF-1. 18. The process of claim 1, wherein the process feedstream is comprised of ethylene, C2H4 and methane, CH4; and the C2+ hydrocarbon compound is ethylene, C2H4. 19. The process of claim 1, wherein the process feedstream is comprised of propylene, C3H6 and methane, CH4; and the C2+ hydrocarbon compound is propylene, C3H6. 20. The process of claim 1, wherein the process feedstream is comprised of a Light Plant Gas feedstream, and the C2+ hydrocarbon compound is selected from the group consisting of C2H4 (ethylene), C2H6 (ethane), C3H6 (propylene), and C3H8 (propane). 21. The process of claim 20, wherein the C2+ hydrocarbon compound partial pressure of the process feedstream in step a) is less than about 29 psia (200 kPaa). 22. The process of claim 20, wherein the process feedstream is at a pressure of less than 100 psia.