초록 ▼

The present invention relates to the selective separation of carbon dioxide (“CO2”) from nitrogen (“N2”) in streams containing both carbon dioxide and nitrogen utilizing a zeolitic imidazolate framework (“ZIF”) material. Preferably, the stream to be separated is fed to the present process in a subst

The present invention relates to the selective separation of carbon dioxide (“CO2”) from nitrogen (“N2”) in streams containing both carbon dioxide and nitrogen 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 carbon dioxide from combustion gas (e.g., flue gas) streams preferably for sequestration of at least a portion of the carbon dioxide produced in combustion processes.

대표청구항 ▼

1. A process for separating CO2 from a process feedstream, comprising: a) contacting an adsorbent bed comprised of a zeolitic imidazolate framework material with a process feedstream comprising CO2 and N2 at a first pressure and first temperature;b) adsorbing at least a portion of the CO2 in the ads

1. A process for separating CO2 from a process feedstream, comprising: a) contacting an adsorbent bed comprised of a zeolitic imidazolate framework material with a process feedstream comprising CO2 and N2 at a first pressure and first temperature;b) adsorbing at least a portion of the CO2 in the adsorbent bed, thereby producing a CO2-lean product stream, wherein the CO2-rich product stream has a higher concentration of CO2 by vol % than the process feedstream; andc) producing a CO2-rich product stream at a second pressure and second temperature, wherein the CO2-rich product stream has a higher concentration of CO2 by vol % 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 are linked by the nitrogen atoms of an imidazolate anion or its derivative, and wherein the zeolitic imidazolate framework material has an adsorptive loading ratio for CO2 over N2 of at least 5; wherein adsorptive loading ratio for Co2 over N2 is measured at 301 K and 106.6 kPa. 2. The process of claim 1 wherein the CO2 partial pressure in step a) is greater than the CO2 partial pressure in step d). 3. The process of claim 1, wherein the zeolitic imidazolate framework material has an adsorptive loading ratio for CO2 over N2 of at least 25. 4. The process of claim 2, wherein the first pressure is greater than the second pressure. 5. The process of claim 4, wherein the second temperature is greater than the first temperature. 6. The process of claim 2, wherein the steps of the process are part of a rapid cycle swing adsorption process and the cycle time of the rapid cycle swing adsorption process is less than about 1 minute. 7. The process of claim 2, wherein the process is a swing adsorption process and the difference between the maximum and minimum CO2 partial pressures achieved in the adsorbent bed during a cycle is less than 300 kPa. 8. The process of claim 2, wherein the CO2 partial pressure of the process feedstream in step a) is less than about 200 kPa. 9. The process of claim 2, wherein the process feedstream is comprised of a combustion gas stream. 10. The process of claim 9, wherein the CO2-rich product stream has a N2 content of less than about 20 vol %. 11. The process of claim 9, wherein the CO2 partial pressure of the process feedstream in step a) is less than about 200 kPa. 12. The process of claim 9, wherein the temperature of the combustion gas stream is reduced prior to contacting the adsorbent bed in step a). 13. The process of claim 10, wherein the combustion gas stream has a N2 content of from about 65 to about 85 vol %. 14. The process of claim 13, wherein the combustion gas stream has a CO2 content of from about 3 to about 25 vol % and the CO2-rich product stream has an CO2 content of at least about 50 vol %. 15. The process of claim 10, wherein at least a portion of the CO2-rich product stream is further treated in an amine unit. 16. The process of claim 9, wherein the process feedstream contacts the adsorbent bed at a pressure from about 0.1 to about 10 psig. 17. The process of claim 9, wherein the zeohtic imidazolate framework material has an adsorptive loading ratio for CO2 over N2 of at least 25. 18. The process of claim 2, wherein the process feedstream is comprised of a FCC regenerator off-gas stream. 19. The process of claim 18, wherein the zeolitic imidazolate framework material has an adsorptive loading ratio for CO2 over N2 of at least 25. 20. The process of claim 2, wherein the process feedstream is comprised of a synthetically produced gas stream and the CO2-rich product stream has a N2 content of less than 10 vol %. 21. The process of claim 20, wherein the zeolitic imidazolate framework material has an adsorptive loading ratio for CO2 over N2 of at least 25. 22. A process for separating CO2 from a process feedstream, comprising: a) contacting an adsorbent bed comprised of a zeolitic imidazolate framework material with a process feedstream comprising CO2 and N2 at a first pressure and first temperature;b) adsorbing at least a portion of the CO2 in the adsorbent bed, thereby producing a CO2-lean product stream, wherein the CO2lean product stream has a lower concentration of CO2 by vol % than the process feedstream; andc) producing a CO2 rich product stream at a second pressure and second temperature, wherein the CO2-rich product stream has a higher concentration of CO2 by vol % 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 are linked by the nitrogen atoms of an imidazolate anion or its derivative, andwherein the zeolitic imidazolate framework material has an adsorptive loading ratio for CO2 over N2 of at least 5; andwherein the CO2 partial pressure in step a) is greater than the CO2 partial pressure in step d); the process feedstream. is comprised of a combustion as stream; the CO2-rich product stream has a N2 content of less than about 20 vol % and at least a portion of the CO2-rich product stream is sequestered at a pressure of at least 500 psig.