Process for concentrating CO
A method for capturing CO 2 from a gas stream using a metal organic framework (MOF) based physisorbent CO 2 concentrator is provided. In the method, a MOF material is pretreated, a gas stream is then introduced into the CO 2 concentrator which comprises the pretreated MOF material. CO 2 from the gas stream is captured with the CO 2 concentrator to generate a CO 2 -free stream, which is discharged from the CO 2 concentrator into the atmosphere. Introduction of the gas stream into the CO 2 concentrator is stopped when the pretreated MOF material becomes saturated with CO 2 . The CO 2 concentrator with the saturated MOF material is then regenerated by introducing hot air, hot nitrogen, vacuum, or a combination thereof into the CO 2 concentrator thereby generating a CO 2 -rich stream. The CO 2 -rich stream is diverted for purification and the regenerated CO 2 concentrator is recycled for future capture of CO 2 .
1 . A method for capturing CO 2 from a gas stream containing approximately 400 ppm to 6% of CO 2 using a metal organic framework (MOF) based physisorbent CO 2 concentrator, comprising:
pretreating a MOF material under airflow or vacuum, wherein the MOF material is KAUST-7;
introducing a gas stream into the CO 2 concentrator which comprises the pretreated MOF material;
capturing, with the CO 2 concentrator, CO 2 from the gas stream to generate a CO 2 -free stream in the CO 2 concentrator;
discharging the CO 2 -free stream from the CO 2 concentrator into the atmosphere;
stopping the introduction of the gas stream into the CO 2 concentrator when the pretreated MOF material becomes saturated with CO 2 ;
regenerating the CO 2 concentrator from the saturated MOF material by introducing hot air, hot nitrogen, or a combination thereof, thereby generating a CO 2 -rich stream, wherein the stream of the hot air or the hot nitrogen or the combination thereof is introduced to the CO 2 concentrator at a temperature of approximately 80-150° C., and wherein the hot air, the hot nitrogen, or the combination thereof exit the CO 2 concentrator as a part of the CO 2 -rich gas stream;
mixing the generated CO 2 -rich gas stream with a stream of industrial exhaust with similar CO 2 concentrations for subsequent purification; and
utilizing the regenerated CO 2 concentrator for future capture of CO 2 .
2 . The method of claim 1 , wherein the CO 2 concentrator comprises the pretreated MOF with a binder in a closed module and one or more gas valves configured to manipulate the flow of the gas stream inside the CO 2 concentrator.
3 . The method of claim 2 , wherein the binder is an organic polymer or an inorganic binder.
4 . The method of claim 1 , wherein the gas stream is gas from a natural gas combined cycle (NGCC) exhaust comprising 2-6% CO 2 , 10-13% 02 and 2-10% H 2 O vapor.
5 . The method of claim 1 , wherein the gas stream is air.
6 . The method of claim 1 , further comprising cooling the gas stream to approximately 20-25° C. before introduction into the CO 2 concentrator.
7 . The method of claim 1 , wherein the MOF material is in the form of pellets, laminates, or other structured forms.
8 . The method of claim 1 , wherein the MOF material is pretreated at a temperature in the range of approximately 60-150° C. under dynamic vacuum or dry inert gas.
9 . The method of claim 1 , wherein the pretreatment of the MOF material removes previously adsorbed molecules.
10 . The method of claim 1 , wherein the generated CO 2 -rich stream has a CO 2 concentration of approximately 1-50%.
11 . The method of claim 1 , wherein the CO 2 -rich stream is 1-10% CO 2 and wherein purification of the CO 2 -rich stream comprises purifying the CO 2 -rich stream to pure CO 2 or to a stream that comprises at least 90% CO 2 .
12 . A method for continuous capturing of CO 2 from a gas stream containing approximately 400 ppm to 6% of CO 2 using multiple metal organic framework (MOF) based physisorbent CO 2 concentrators, comprising:
pretreating a MOF material under airflow or vacuum, wherein the MOF material is KAUST-7;
introducing a gas stream into a first CO 2 concentrator which comprises the pretreated MOF material;
capturing, with the first CO 2 concentrator, CO 2 from the gas stream to generate a CO 2 -free stream in the first CO 2 concentrator;
discharging the CO 2 -free stream from the first CO 2 concentrator into the atmosphere;
substituting a second CO 2 concentrator comprising pretreated MOF material for the first CO 2 concentrator when the pretreated MOF material of the first CO 2 concentrator becomes saturated with CO 2 ;
regenerating the first CO 2 concentrator from the saturated MOF material by introducing hot air, hot nitrogen, or a combination thereof, thereby generating a CO 2 -rich stream, wherein the stream of the hot air or the hot nitrogen or the combination thereof is introduced to the CO 2 concentrator at a temperature of approximately 80-150° C., and wherein the hot air, the hot nitrogen, or the combination thereof exit the CO 2 concentrator as a part of the CO 2 -rich gas stream;
mixing the generated CO 2 -rich gas stream with a stream of industrial exhaust with similar CO 2 concentrations for subsequent purification; and
recycling the regenerated first CO 2 concentrator for future capture of CO 2 .
13 . The method of claim 12 , wherein the gas stream is gas from a natural gas combined cycle (NGCC) exhaust comprising 2-6% CO 2 , 10-13% 02 and 2-10% H 2 O vapor.
14 . The method of claim 12 , wherein the MOF material is pretreated at a temperature in the range of approximately 60-150° C. under dynamic vacuum or dry inert gas, and further comprising the step of cooling the gas stream to approximately 20-25° C. before introduction into the first CO 2 concentrator.