A process for separating carbon dioxide from a fluid containing carbon dioxide, NO.sub.2, and at least one of oxygen, argon, and nitrogen comprises the steps of separating at least part of the fluid into a carbon dioxide enriched stream, a carbon dioxide depleted stream comprising CO.sub.2 and at least one of oxygen, argon, and nitrogen and a NO.sub.2 enriched stream and recycling said NO.sub.2 enriched stream upstream of the separation step.

Provided is a method for reusing an adsorbent which can stably exhibit purification ability by regenerating a used absorbent, in order to keep the composition of a purified syngas constant.

The present invention concerns a method for regenerating a zeolite adsorbent which adsorbs a carbon dioxide gas from a syngas comprising the carbon dioxide gas and reduces the concentration of the carbon dioxide gas in the syngas, comprising: a step of recovering a used zeolite adsorbent; a step of calcining the used zeolite adsorbent at a temperature of 300° C. to 600° C. in an oxygen atmosphere to produce a regenerated zeolite adsorbent; and a step of reusing the regenerated zeolite adsorbent.

A method for adjusting a gas stream separation unit having N adsorbers, where N≥2, each following a PSA, VSA or VPSA adsorption cycle, with a time lag of a phase time, said adjustment method including continuously measuring a physical parameter associated with the gas stream entering and/or leaving the adsorber; for at least one step of the adsorption cycle, determining at least one characteristic value of the step chosen in step a) which is selected from the values of the physical parameter measured in step a) or a function of those values; comparing this characteristic value with a target value; and modifying the flow of the gas stream in order to obtain the target value, in the event of a variation between the value of this (these) difference(s) and the target values.

A purification system for recovering carbon dioxide from a gaseous carbon dioxide stream originating from a fermentation process, brewery or a bottling line is provided. The purification system includes a compressor in fluid communication with an absorber. The compressor provides a compressed gaseous stream at a predetermined pressure and the absorber separates the compressed gaseous stream into a carbon dioxide rich gaseous stream and a contaminant rich stream. A condenser is designed to operate at a pressure of at least 30 bar and is designed to separate the carbon dioxide rich gaseous stream into a condensate and a purge gas. A distillation column is configured to separate the condensate into a second purge gas and a purified carbon dioxide stream.

A device for testing performance of photocatalytic ozonation in degradation of volatile organic compounds. The device includes an air generator, an oxygen cylinder, a volatile organic compound cylinder, a mass flow meter, an ozone generator, a humidifier, a thermohygrometer, a gas mixer, a light source, a plate-type reactor, an ozone analyzer, a gas chromatographic instrument, a first valve, a second valve, a third valve and a tail gas treatment unit; The experimental device of the present invention is suitable for the experiment of photocatalytic degradation of volatile organic gases in mixed gas, and has the advantages of wide experimental conditions, simple structure, convenient use, reliable performance, etc.

Disclosed is an adsorbent containing a metal oxide for adsorption of hydrogen sulfide in biogas, and a biogas purification system using the same.

A fuel cell system includes a first fuel cell having a first anode and a first cathode, wherein the first anode is configured to output a first anode exhaust gas. The system further includes a first oxidizer configured to receive the first anode exhaust gas and air from a first air supply, to react the first anode exhaust gas and the air in a preferential oxidation reaction, and to output an oxidized gas. The system further includes a second fuel cell configured to act as an electrochemical hydrogen separator. The second fuel cell includes a second anode configured to receive the oxidized gas from the first oxidizer and to output a second anode exhaust gas, and a second cathode configured to output a hydrogen stream. The system further includes a condenser configured to receive the second anode exhaust gas and to separate water and CO.sub.2.

The invention present provides a method (and suitable apparatus) to convert biomass to ethanol, comprising gasifying the biomass to produce raw syngas; feeding the raw syngas to an acid-gas removal unit to remove at least some CO.sub.2 and produce a conditioned syngas stream; feeding the conditioned syngas stream to a fermentor to biologically convert the syngas to ethanol; capturing a tail gas from an exit of the fermentor, wherein the tail gas comprises at least CO.sub.2 and unconverted CO or H.sub.2; and recycling a first portion of the tail gas to the fermentor and/or a second portion of the tail gas to the acid-gas removal unit. This invention allows for increased syngas conversion to ethanol, improved process efficiency, and better overall biorefinery economics for conversion of biomass to ethanol.

A gas compression system includes a system inlet to receive a gas stream containing a first component and a second component, a vapor system outlet to discharge the gas stream, and a plurality of compression stages coupled in series between the system inlet and the vapor system outlet. Each of the plurality of compression stages includes a compressor, a condenser coupled to the compressor, and a gravity-independent phase separator coupled to the condenser. The compressor is configured to receive the gas stream from either the system inlet or another of the plurality of compression stages and compress the gas stream. The condenser is configured to condense the second component from the gas stream. The gravity-independent phase separator is configured to remove the second component from the gas stream and discharge the gas stream to either the system outlet or another of the plurality of compression stages.

Systems and methods to separate carbon dioxide from flue gases and sequester carbon dioxide are described here. By using the properties of carbon dioxide and the temperature in a body of water (e.g., the ocean or freshwater body of water) or the temperatures of the ambient atmosphere, gaseous carbon dioxide can be converted to a liquid and separated from other gases. Pressure used to separate carbon dioxide from other gases may also be used to sequester liquid carbon dioxide. The liquid carbon dioxide is inert and can be discharged into the ocean without dissolving in seawater and acidifying the ocean. The liquid carbon dioxide may further be densified to be denser than seawater. The liquid carbon dioxide can then sink to the bottom of the ocean or be injected into ocean sediments or sediments and rocks beneath the ocean floor, inert and sequestered for the long term.