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US 10,780,387 B1Granted
System and method for gas quality and efficiency of a pressure swing adsorption gas separation unit
AssigneeArc Technologies, Inc.
InventorStanley Michael Siegel
Life of this patent
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Abstract
The invention provides a system and method that applies novel algorithms and compositions for efficiently adjusting compression, unit turn down, pressure and flows of a pressure swing adsorption unit. The present invention also reduces overall horsepower, increases unit's product gas recovery, maximizes product gas quality and allows for non-disturbance of upstream and downstream equipment in regard to pressure and flow oscillations. Raw gas streams addressed include methane (CH4), nitrogen (N2), oxygen (O2), carbon dioxide (CO2), water (H2O), Hydrogen Sulfide (H2S) and non-methane organic compounds (NMOC) gases/vapors. The invention incorporates a CO2 and H2O trim units and provides a VPSA N2 and O2 rejection section.
Claims15
A method for processing and purifying a gas stream comprises:
- collecting a raw gas stream which includes at least methane (CH4), nitrogen (N2), oxygen (O2), carbon dioxide (CO2), water (H2O), Hydrogen Sulfide (H2S) and non-methane organic compounds (NMOC) gases/vapors;
- separating the raw gas stream using H2S and NMOC removal and creating at least one intermediate NMOC and H2S stream, wherein an exiting treated gas stream is enriched in CH4, N2, O2, CO2, H2O, N2 and depleted in NMOC and H2S relative to the raw gas stream;
- further partially separating the treated gas stream using CO2 and H2O removal and creating at least one intermediate CO2 and H2O stream, wherein a new produced first product gas stream is enriched in CH4, N2, O2 and partially depleted in CO2 and H2O relative to the first product gas stream;
- further separating the first product gas stream using at least two PSA vessels that have adsorbent material selective of H2O and or CO2 and creating at least one intermediate CO2 and or H2O stream, wherein a new produced Trimmed stream is enriched in CH4, O2, N2 and depleted in CO2 and H2O relative to the first product gas stream;
- further separating the Trimmed gas stream using at least two Vacuum Swing Adsorption (VPSA) vessels having adsorbent material selective of CH4 and creating a new commercial heavy product stream enriched in CH4 and depleted in N2 and O2 relative to the Trimmed gas stream, directing the produced commercial product gas stream to at least one commercial heavy product buffer vessel and a second produced light gas product stream directed to a purge unit and or a light product buffer vessel;
- providing at least one equalization stream between said VPSA vessels, wherein the equalization stream is enriched in N2 and lightly depleted in CH4 relative to a higher pressurized VPSA vessel's adsorbent gas content;
- sensing at least one gas adsorption temperature in said VPSA vessels, and using sensed increasing gas adsorption temperature to command the end of vessel's adsorption sequence;
- providing at least one purge stream between said PSA vessels and said VPSA vessels, wherein the purge stream is enriched in N2 and O2 and depleted in CH4, CO2 and H2O relative to a lower pressurized upstream PSA vessel with exiting purge flow to a light buffer vessel;
- and
- providing at least one computerized process schema outputting PID loop outputs, controlling analog valves, and prioritizing and balancing gas pressures and gas flows.
7 more elements
A system for processing and purifying a gas stream comprises:
- A raw gas stream piping flow network to convey at least methane (CH4), nitrogen (N2), oxygen (O2), carbon dioxide (CO2), water (H2O), Hydrogen Sulfide (H2S) and non-methane organic compounds (NMOC) gases/vapors;
- a raw gas separation unit for H2S and NMOC removal, and creating at least one intermediate NMOC and H2S stream, wherein the exiting treated gas stream is enriched in CH4, N2, O2, CO2, H2O and depleted in NMOC and H2S relative to the raw gas stream;
- a treated gas separation unit for CO2 and H2O removal and creating at least one intermediate CO2 and H2O stream, wherein the new produced first product gas stream is enriched in CH4, N2, O2, N2 and partially depleted in CO2 and H2O relative to the exiting treated gas stream;
- a Trim unit to separate the first product gas stream using at least two PSA vessels having adsorbent material selective of H2O and or CO2 and creating at least one intermediate CO2 and or H2O stream, wherein a new Trimmed product stream is enriched in CH4, O2, N2 and depleted in CO2 and H2O relative to the first product gas stream;
- a VPSA gas separation unit to produce a commercial product gas stream using at least two Vacuum Swing Adsorption (VPSA) vessels having adsorbent material selective of CH4 and wherein creating a new commercial product stream enriched in CH4 and depleted in N2 and O2 relative to the Trimmed stream;
- at least one equalization conduit between said VPSA vessels, wherein an equalization stream is enriched in N2 and lightly depleted in CH4 relative to higher pressurized VPSA vessel's adsorbent gas content;
- at least one gas temperature sensor in said VPSA vessels, sensing gas adsorption temperature flow and using increasing temperature values to command an end of said vessel's adsorption sequence;
- at least one purge conduit between said Trim Unit and said VPSA vessels, wherein a purge stream is enriched in N2 and O2 and depleted in CH4, CO2 and H2O relative to a lower pressurized PSA vessel;
- and
- at least one computer with a process analog valve for prioritizing and balancing gas pressures and gas flow.
7 more elements
Dependencies are inferred from the claim text.