US 12,605,670 B2Granted

Biogas halogenated volatile organic compound and acid removal systems and methods

AssigneeStearns, Conrad and Schmidt, Consulting Engineers, Inc.

InventorJeffrey Grill

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Abstract

A method to produce an acid-depleted biogas is described. The method includes supplying biogas to a biogas acid removal system to produce an acid-depleted biogas. Biogas pre-processing, post-processing, and a product production system may be integrated with the biogas acid removal process to produce a product. A two-stage volatile organic compound removal process is also described including a volatile organic compound removal step, and a halogenated volatile organic compound removal step, followed by an acid removal step. Oxygen removal from the biogas is also provided by combusting oxygen together with halogenated volatile organic compounds within the biogas, followed by removing acid generated in the combustion of the halogenated volatile organic compounds.

Claims19

Dependent claims

A method to produce a water-depleted gas, comprising:

providing a pre-processing system configured to accept a gas comprising at least methane, oxygen, and a halogenated volatile organic compound, wherein said gas is a source of biogas, and to subject said gas to a combustion process within said pre-processing system to produce a pre-processed gas;
wherein said pre-processed gas comprises carbon dioxide, water vapor, a reduced amount of said oxygen, and a reduced amount of said halogenated volatile organic compound relative to said gas, wherein a halogen portion of said halogenated volatile organic compound is dissociated into said halogen by said combustion process, wherein said halogen combines with said water vapor within said pre-processed gas to produce an acid, wherein said pre-processed gas comprises at least said acid and said water vapor, and said pre-processing system is further configured to evacuate said pre-processed gas from said pre-processing system and supply said pre-processed gas to an acid removal system;
providing said acid removal system comprising an acid removal material, said acid removal system is configured to accept said pre-processed gas and contact said pre-processed gas with said acid removal material within said acid removal system to remove at least a portion of said acid from said pre-processed gas to produce an acid-depleted gas, said acid-depleted gas comprises a reduced amount of said acid relative to said pre-processed gas;
wherein said acid removal system does not comprise a liquid caustic scrubber;
wherein said acid removal system is further configured to evacuate said acid-depleted gas from said acid removal system and supply said acid-depleted gas to a temperature swing adsorption water removal process;
providing said temperature swing adsorption water removal process configured to accept said acid-depleted gas from said acid removal system and remove at least a portion of said water vapor from said acid-depleted gas to produce said water-depleted gas, wherein said water-depleted gas comprises a reduced amount of said water vapor relative to said acid-depleted gas;
supplying said gas to said pre-processing system, and within said pre-processing system, subjecting said gas to said combustion process to produce said pre-processed gas, said pre-processed gas comprises an increased amount of carbon dioxide, an increased amount of water vapor, a reduced amount of said oxygen, and a reduced amount of said halogenated volatile organic compound relative to said gas, wherein said halogen portion of said halogenated volatile organic compound is dissociated into said halogen by said combustion process, wherein said halogen combines with said water vapor within said pre-processed gas to produce said acid;
supplying said pre-processed gas to said acid removal system, wherein within said acid removal system said pre-processed gas is contacted with said acid removal material to remove at least a portion of said acid from said pre-processed gas to produce said acid-depleted gas, wherein said acid-depleted gas comprises a reduced amount of said acid relative to said pre-processed gas;
and
supplying said acid-depleted gas to said temperature swing adsorption water removal process to remove at least a portion of said water vapor from said acid-depleted gas to produce said water-depleted gas, said water-depleted gas comprises a reduced amount of said water vapor relative to said acid-depleted gas, said increased amount of carbon dioxide, said reduced amount of said oxygen, and said reduced amount of said halogenated volatile organic compound, wherein said at least a portion of said water is removed from said acid-depleted gas without supplying said acid-depleted gas to a carbon dioxide removal process.

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A method to produce a water-depleted gas, comprising:

providing a gas comprising carbon dioxide, methane, and a halogenated volatile organic compound, wherein said gas is a processed source of biogas and/or includes biogas;
removing at least a portion of said carbon dioxide from said gas to produce a carbon dioxide depleted gas, wherein said carbon dioxide depleted gas comprises a reduced amount of said carbon dioxide relative to said gas;
removing at least a portion of said halogenated volatile organic compound from said carbon dioxide depleted gas to produce a halogenated volatile organic compound depleted gas by subjecting said carbon dioxide depleted gas to a combustion process and/or contacting said carbon dioxide depleted gas with a catalyst, wherein said halogenated volatile organic compound depleted gas comprises a reduced amount of said halogenated volatile organic compound relative to said carbon dioxide depleted gas, wherein said halogenated volatile organic compound depleted gas comprises an acid and water vapor;
contacting at least a portion of said halogenated volatile organic compound depleted gas with an acid removal material to remove at least a portion of said acid from said halogenated volatile organic compound depleted gas to produce an acid-depleted gas, wherein said acid-depleted gas comprises a reduced amount of said acid relative to said halogenated volatile organic compound depleted gas;
wherein said acid removal material comprises one or more materials selected from the group consisting of an adsorbent, activated alumina, activated carbon, alumina, carbon, carbon nanotubes, catalyst, ceramic material, chitosan, chitin, clay, a dry scrubbing agent, an engineered reactant, iron sponge, an ion-exchange resin, molecular sieve, a polymeric adsorbent, promoted alumina, a reactant, a scavenger, silica gel, a base, a neutralizing agent, a pH buffer, and a zeolite;
and
removing at least a portion of said water vapor from said acid-depleted gas to produce said water-depleted gas, wherein said water-depleted gas comprises a reduced amount of said water vapor relative to said acid-depleted gas.

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Dependencies are inferred from the claim text.

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Abstract

A method to produce a water-depleted gas, comprising:

providing a pre-processing system configured to accept a gas comprising at least methane, oxygen, and a halogenated volatile organic compound, wherein said gas is a source of biogas, and to subject said gas to a combustion process within said pre-processing system to produce a pre-processed gas;
wherein said pre-processed gas comprises carbon dioxide, water vapor, a reduced amount of said oxygen, and a reduced amount of said halogenated volatile organic compound relative to said gas, wherein a halogen portion of said halogenated volatile organic compound is dissociated into said halogen by said combustion process, wherein said halogen combines with said water vapor within said pre-processed gas to produce an acid, wherein said pre-processed gas comprises at least said acid and said water vapor, and said pre-processing system is further configured to evacuate said pre-processed gas from said pre-processing system and supply said pre-processed gas to an acid removal system;
providing said acid removal system comprising an acid removal material, said acid removal system is configured to accept said pre-processed gas and contact said pre-processed gas with said acid removal material within said acid removal system to remove at least a portion of said acid from said pre-processed gas to produce an acid-depleted gas, said acid-depleted gas comprises a reduced amount of said acid relative to said pre-processed gas;
wherein said acid removal system does not comprise a liquid caustic scrubber;
wherein said acid removal system is further configured to evacuate said acid-depleted gas from said acid removal system and supply said acid-depleted gas to a temperature swing adsorption water removal process;
providing said temperature swing adsorption water removal process configured to accept said acid-depleted gas from said acid removal system and remove at least a portion of said water vapor from said acid-depleted gas to produce said water-depleted gas, wherein said water-depleted gas comprises a reduced amount of said water vapor relative to said acid-depleted gas;
supplying said gas to said pre-processing system, and within said pre-processing system, subjecting said gas to said combustion process to produce said pre-processed gas, said pre-processed gas comprises an increased amount of carbon dioxide, an increased amount of water vapor, a reduced amount of said oxygen, and a reduced amount of said halogenated volatile organic compound relative to said gas, wherein said halogen portion of said halogenated volatile organic compound is dissociated into said halogen by said combustion process, wherein said halogen combines with said water vapor within said pre-processed gas to produce said acid;
supplying said pre-processed gas to said acid removal system, wherein within said acid removal system said pre-processed gas is contacted with said acid removal material to remove at least a portion of said acid from said pre-processed gas to produce said acid-depleted gas, wherein said acid-depleted gas comprises a reduced amount of said acid relative to said pre-processed gas;
and
supplying said acid-depleted gas to said temperature swing adsorption water removal process to remove at least a portion of said water vapor from said acid-depleted gas to produce said water-depleted gas, said water-depleted gas comprises a reduced amount of said water vapor relative to said acid-depleted gas, said increased amount of carbon dioxide, said reduced amount of said oxygen, and said reduced amount of said halogenated volatile organic compound, wherein said at least a portion of said water is removed from said acid-depleted gas without supplying said acid-depleted gas to a carbon dioxide removal process.

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