Separation of carbon dioxide from methane utilizing zeolitic imidazolate framework materials
AssigneeExxonMobil Research and Engineering Company
InventorsSebastian C. Reyes, Zheng Ni, Charanjit S. Paur, Pavel Kortunov, John Zengel, Harry W. Deckman
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Abstract
The present invention relates to the selective separation of carbon dioxide (“CO2”) from methane (“CH4”) in streams containing both carbon dioxide and methane 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 natural gas streams preferably for sequestration of at least a portion of the carbon dioxide present in the natural gas.
Claims21
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 CH4 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-lean product stream has a lower concentration of CO2 by vol % than the process feedstream;
- and
- c) 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 is linked by nitrogen atoms of an imidazolate anion or its derivative, and wherein the zeolitic imidazolate framework material has an adsorptive loading ratio for CO2 over CH4 of at least 10;
- and the adsorptive loading ratio for CO2 over CH4 is measured at 301 K and 106.6 kPa.
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 CH4 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-lean product stream has a lower concentration of CO2 by vol % than the process feedstream;
- and
- c) 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 is linked by nitrogen atoms of an imidazolate anion or its derivative, and wherein the zeolitic imidazolate framework material has an adsorptive loading ratio for CO2 over CH4 of at least 10;
- and the process feedstream is comprised of a natural gas and at least a portion of the CO2-rich product stream is sequestered at a pressure of at least 500 psig.
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 CH4 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-lean product stream has a lower concentration of CO2 by vol % than the process feedstream;
- and
- c) 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 is linked by nitrogen atoms of an imidazolate anion or its derivative, and wherein the zeolitic imidazolate framework material has an adsorptive loading ratio for CO2 over CH4 of at least 10, wherein the adsorptive loading ratio for CO2 over CH4 is measured at 301 K and 106.6 kPa;
- and the process feedstream is comprised of an organically derived gas stream selected from a landfill produced gas and a biogenically produced gas;
- and the process feedstream contacts the adsorbent bed at a pressure of less than about 50 psig.
Dependencies are inferred from the claim text.