Process for purifying hydrogen gas for use in fuel cells
The invention generally relates to a process for purifying a hydrogen gas for use in a fuel cell. The process involves taking a hydrogen feed stream from a high-pressure tank and passing it through a purifier comprising an adsorbent to provide a purified hydrogen stream which is sent to a fuel cell. A particular adsorbent which can be used is a metal-organic framework composition. The adsorbent can be housed in a device such as a canister or cartridge having an inlet and outlet port.
1. A process for providing purified hydrogen to a hydrogen fuel cell, the process comprising:
providing a system comprising a high-pressure tank containing hydrogen gas having at least one contaminant, a purifier containing an adsorbent, and a fuel cell;
flowing a hydrogen stream from said high-pressure tank through said purifier at purification conditions thereby substantially removing said at least one contaminant to provide a purified hydrogen stream, and
flowing said purified hydrogen stream to said fuel cell.
2. The process of claim 1 where the at least one contaminant is selected from H 2 S, CO, formaldehyde, CO 2 , COS, CS 2 , methyl mercaptan, NH 3 , hydrocarbons, halogenates, and water.
3. The process of claim 1 where the purified hydrogen stream has a purity of at least 99.7%.
4. The process of claim 1 where the purifier is operated at a temperature from about −40° C. to about 40° C. and a pressure from about 100 kPa to about 84 MPa.
5. The process of claim 1 further characterized in that the purifier comprises a cartridge which contains the adsorbent.
6. The process of claim 5 where the cartridge is a disposable cartridge.
7. The process of claim 1 where the adsorbent is selected from metal organic frameworks (MOFs), zeolites, activated carbon, covalent organic frameworks (COFs), porous organic polymers (POPs) and mixtures thereof.
8. The process of claim 1 where the purifier comprises at least two different adsorbents.
9. The process of claim 7 where the adsorbent comprises a MOF and the MOF comprises metal ion corner atoms where the metal ion is selected from Li + , Na + , K + , Rb + , Be 2+ , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , Sc 3+ , Y 3+ , Ti 4+ , Zr 4+ , Hf 4+ , V 5+ , V 4+ , V 3+ , Nb 3+ , Ta 3+ , Cr 3+ , Cr 2+ , Mo 3 , W 3+ , Mn 3+ , Fe 3+ , Fe 2+ , Ru 3+ , Ru 2+ , Os 3+ , Os 2+ , Co 3 , Co 2+ , Ni 2+ , Ni + , Pd 2+ , Pd + , Pt 2+ , Pt + , Cu 2+ , Cu + , Ag + , Au + , Zn 2+ , Al 3+ , Ga 3+ , In 3+ , Si 4+ , Si 2+ , Ge 4+ , Ge 2+ , Sn 4+ , Sn 2+ , Bi 5+ , Bi 3+ , Cd 2+ , Mn 2+ , Tb 3+ , Gd 3+ , Ce 3+ , La 3+ and Cr 4+ , and mixtures thereof, the metal ions being joined by an at least bidentate organic linker molecules to form a metal organic framework, the at least bidentate organic linker molecules being selected from one or more molecules comprising a linker backbone comprising one or more groups selected from 1) saturated or unsaturated, linear, branched or cyclic alkyl groups having from 1 to 10 carbon atoms and optionally comprising heteroatoms; and 2) groups comprising 1 to 5 aryl or heteroaryl rings which can be fused or joined covalently; wherein the hetero atoms are selected from S, N, O, P and mixtures thereof; and optionally comprising one or more functional groups selected from one or more of saturated and unsaturated alkyl, aryl, heteroaryl, halide, —OH, —NH 2 , —COOH, NO 2 , COH, CO(NH 2 ), CN and thiols.
10. The process of claim 9 where the metal ion is selected from Ti 4+ , Zr 4+ , Hf 4+ , Fe 3+ , Fe 2+ , Co 3+ , Co 2+ , Ni 2+ , Ni + , Cu 2+ , Cu + , Zn 2+ , Ga 3+ , Al 3+ and mixtures thereof and the linker molecule is selected from 1,3,5-benzene tricarboxylic acid (BTC), triazine tris-benzoic acid (TATB), 2-amino-terephthalic acid, naphthalene dicarboxylate (NDC), acetylene dicarboxylate (ATC), benzene-1,4- dicarboxylic acid (BDC), benzene tribenzoate (BTB), methane tetrabenzoate (MTB), adamantane tetracarboxylate (ATC), adamantane tribenzoate (ATB), 4,4′,4″,4′″-(pyrene-1,3,6,8-tetrayl)tetrabenzoic acid (TBAPy), meso-Tetraphenylporphine-4,4′,4″,4′″-tetracarboxylic acid (TCPPH2), 3,3′,5,5′-azobenzenetetracarboxylic acid, 2,5-dihydroxyterephthalic acid, pyrazine, 1,4-diazabicyclo[2.2.2]octane, and mixtures thereof.
11. The process of claim 1 where the adsorbent has a B. E. T. surface area of at least 200 m 2 /g.
12. The process of claim 9 where the MOF has an average pore size from about 2 angstroms to about 500 angstroms.
13. The process of claim 1 where the adsorbent is in the form of a bed through which the hydrogen stream flows.
14. The process of claim 1 further characterized in that the adsorbent is deposited onto a solid support selected from a membrane, woven fiber, non-woven fiber, a monolithic support, a ceramic foam, a metal support, and mixtures thereof.
15. The process of claim 1 further characterized in that the adsorbent is formed into a shape selected from pellets, spheres, extrudates, irregularly shaped particles, monolithic shapes, and mixtures thereof.
16. The process of claim 9 where the MOF is selected from MOF-74-Co, MOF-74-Ni, MOF-74-Cu, PCN-250, HKUST-1, UiO-66, UiO-66-NH 2 , SIFSIX-3, MIL-88, MIL-89, Ga-soc-MOF, Zn 2 (BDC) 2 (DABCO), and mixtures thereof.
17. The process of claim 1 further characterized in that the process is carried out onboard a vehicle.
18. The process of claim 17 where the hydrogen stream is flowed through the purifier at a flow rate from about 0.05 kg/hr. to about 2 kg/hr.
19. The process of claim 4 where the pressure is from about 100 kPa to about 40 MPa.
20. The process of claim 1 further characterized in that the adsorbent is regenerated by changing the temperature or changing the pressure.
21. The process of claim 1 further characterized in that the high-pressure tank, purifier and fuel cell are part of a stationary power system.
22. The process of claim 21 where the stationary power system is housed in a container and the power system provides power to a building.
23. The process of claim 21 where the hydrogen stream is flowed through the purifier at a flow rate from about 0.2 kg/hr. to about 10 kg/hr.
24. A process for purifying hydrogen, the process comprising
flowing a hydrogen stream comprising hydrogen and at least one contaminant from a high-pressure tank through a purifier comprising a metal organic framework adsorbent at purification conditions, thereby substantially removing said at least one contaminant,
wherein the MOF is selected from MOF-74-Co, MOF-74-Ni, MOF-74-Cu, PCN-250, HKUST-1, UiO-66, UiO-66-NH 2 , SIFSIX-3, MIL-88, MIL-89, Ga-soc-MOF, Zn 2 (BDC) 2 (DABCO), and mixtures thereof.