A process and apparatus for producing a hydrogen-enriched product and recovering CO.sub.2 from an effluent stream from a hydrogen production unit are described. The effluent from the hydrogen production unit, which comprises a mixture of gases comprising hydrogen, carbon dioxide, water, and at least one of methane, carbon monoxide, nitrogen, and argon, is sent to a PSA system that produces at least two product streams for separation. The PSA system that produces at least two product streams separates the gas mixture into a high-pressure hydrogen stream enriched in hydrogen, optionally a second gas stream containing the majority of the impurities, and a low-pressure tail gas stream enriched in CO.sub.2 and some impurities. The CO.sub.2-rich tail gas stream is compressed and sent to a CO.sub.2 recovery unit, where a CO.sub.2-enriched stream is recovered. The CO.sub.2-depleted overhead gas stream is recycled to the PSA system that produces at least two product streams.

In a carbon dioxide recovery system. an electrochemical cell of a recovery device includes a working electrode having an adsorbent capable of adsorbing carbon dioxide, and a counter electrode paired with the working electrode. A sensor detects a recovery amount that is an amount of carbon dioxide recovered in the recovery device and sent to a carbon dioxide recovery tank. A controller applies a first potential between the electrodes only for an adsorption time period in an adsorption mode such that the adsorbent adsorbs carbon dioxide. The adsorption time period corresponds to a target adsorption amount that is an amount of carbon dioxide that can be adsorbed by the adsorbent. The controller applies a second potential between the electrodes in a recovery mode such that the adsorbed carbon dioxide is desorbed. The controller acquires the target adsorption amount as a correlation value correlated with the detected recovery amount.

The disclosure relates to a rotary kiln catalytically enhanced oxy-fuel gasification and oxy-fuel combustion system—power plant including an air separation unit arranged to separate oxygen from air and produce a stream of substantially pure liquid oxygen; rotary kiln gasifiers to convert municipal solid waste, biomass, alternate wastes, coal, or hydrocarbon fuels into a synthesis gas in the presence of oxygen, carbon dioxide, high temperature steam and lime catalysts; an oxy-fuel fired boiler arranged to combust synthesis gas, in the presence of substantially pure oxygen gas, to produce an exhaust gas comprised of water and carbon dioxide; and a carbon dioxide removal unit arranged to recover carbon dioxide gas from the exhaust gas, recycle a portion of the recovered carbon dioxide gas for use in the rotary kiln gasifier, and liquefy the remainder of the recovered carbon dioxide gas for removal from the plant. In this new plant, the carbon dioxide removal unit is thermally integrated with the air separation unit or alternately the liquid oxygen storage and supply system by directing a stream of liquid oxygen to the carbon dioxide removal unit to liquefy the recovered carbon dioxide gas, the liquid oxygen thereby evaporating and forming cold oxygen gas which is heated prior to consumption in the rotary kiln and oxy-fuel fired boiler.

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

A gas recovery system includes: a working electrode that adsorbs a recovery target gas; a counter electrode that exchanges electrons with the working electrode; a working-electrode current collector in contact with the working electrode to electrically connect the working electrode and the counter electrode; and a counter-electrode current collector in contact with the counter electrode to electrically connect the working electrode and the counter electrode. The working-electrode current collector has a working electrode opening to expose the working electrode to the gas mixture. The counter-electrode current collector has a counter electrode opening to expose the counter electrode to the gas mixture. An opening area of the counter electrode opening is smaller than an opening area of the working electrode opening.

A carbon dioxide recovery system separates CO.sub.2 from gas containing CO.sub.2 via an electrochemical reaction. The carbon dioxide recovery system includes an electrochemical cell including a working electrode and a counter electrode. The working electrode includes CO.sub.2 adsorbent. The CO.sub.2 adsorbent adsorbs CO.sub.2 via an oxygen reduction reaction by using electrons supplied from the counter electrode to the working electrode when a first voltage is applied between the working electrode and the counter electrode. The oxygen reduction reaction produces active oxygen via reduction of O.sub.2. The CO.sub.2 adsorbent desorbs CO.sub.2 by discharging electrons from the working electrode to the counter electrode when a second voltage different from the first voltage is applied between the working electrode and the counter electrode. The CO.sub.2 adsorbent has a promoting function for promoting the oxygen reduction reaction.

A movable carbon capture system applied to agriculture-harmonious buildings, which includes a carbon capture unit and a high-concentration CO.sub.2 supply unit which are respectively integrated, wherein the carbon capture unit comprises a CO.sub.2 adsorption chamber and an air pump, and the high-concentration CO.sub.2 supply unit comprises a vacuum pump and an air storage cavity; an air inlet of the CO.sub.2 adsorption chamber is connected to the indoor environment, an exhaust port of the CO.sub.2 adsorption chamber is connected to an atmosphere outlet, an air outlet of the CO.sub.2 adsorption chamber is connected with an air inlet of the vacuum pump, an air outlet of the vacuum pump is connected with an air inlet of the air storage cavity, an air outlet of the air storage cavity is connected with a greenhouse air supply port, and the greenhouse air supply port is connected with a greenhouse.

A system for synchronously recovering nitrogen and carbon dioxide from boiler flue gas includes: a flue gas pretreatment system used for dehydrating and cooling boiler flue gas; a carbon and nitrogen separation system communicated with the flue gas pretreatment system, and used for performing pressure swing adsorption on the pretreated flue gas and separating the nitrogen-containing vent gas and the crude carbon dioxide gas; a carbon dioxide secondary purification system communicated with the carbon and nitrogen separation system, and used for performing secondary purification on the crude carbon dioxide gas separated from the carbon and nitrogen separation system; and a nitrogen concentration and purification system communicated with the carbon and nitrogen separation system and the carbon dioxide secondary purification system, and used for purifying the nitrogen-containing vent gas separated from the carbon and nitrogen separation system and the vent gas generated by the carbon dioxide secondary purification system.

Disclosed is an improved method and system of operating the semi-closed cycle, which both reduces parasitic loads for oxygen generation and for gas clean up, while also reducing, capital cost of the gas clean up plant (reduced drying requirement) and of the oxygen plant (enabling membranes vs. mole sieves). The invention is applicable to piston or turbine engines, and results in a near fully non-emissive power system via the Semi-Closed Cycle (SCC), in a manner which both captures carbon in the form of carbon dioxide, CO2, and in a manner which improves the efficiency and cost effectiveness of prior disclosures. The captured carbon is of a purity and pressure directly suitable for Enhanced Oil Recovery (EOR), sequestration, or industrial use.

The present invention provides a process of cultivating microalgae and a joint method of same jointed with denitration. During the microalgae cultivation, EM bacteria is added into the microalgae suspension. In the nutrient stream for cultivating microalgae, at least one of the nitrogen source, phosphorus source and carbon source is provided in the form of a nutrient salt. During the cultivation, the pH of the microalgae suspension is adjusted with nitric acid and/or nitrous acid. The joint method includes (1) a step of cultivating microalgae; (2) a separation step of separating a microalgae suspension obtained from step (1) into a wet microalgae (microalgae biomass) and a residual cultivation solution; and (3) a NOx absorbing/immobilizing step of denitrating an industrial waste gas with the residual cultivation solution obtained from step (2). The nutrient stream absorbed with NOx obtained from step (3) is used to provide nitrogen source to the microalgae cultivation of step (1).