Solid sorbents, and especially zeolites, are attractive candidates for CO.sub.2 direct air capture (DAC) and point source capture applications because of their potential for high selectivity, fast kinetics, and low energy CO.sub.2 capture cycles. A common issue with solid sorbents, including zeolites, is their low thermal conductivity, which makes them difficult to heat for regeneration without using complex and expensive heat transfer systems. This invention utilizes a modified TVSA process which utilizes the product CO.sub.2 gas itself as the heating medium for the adsorbent bed, alone or in conjunction with internal or external heaters. The use of CO.sub.2 as a heating medium allows efficient heating of the sorbent bed and enables high purity CO.sub.2 product.

An evaluation method capable of evaluating whether or not waste plastic-derived porous carbon can be applied on an industrial scale, according to the present disclosure, may include the steps of evaluating CO.sub.2 capture performance using a 5-step temperature vacuum swing adsorption (TVSA) process, assessing economic feasibility in an industry using a techno-economic assessment (TEA) method, and quantifying environmental impacts of the porous carbon production pathway and global warming potential (GWP) using cradle-to-gate life-cycle assessment (LCA).

A method for manufacturing porous carbon, according to the present disclosure, may include the steps of carbonizing a polyethylene terephthalate plastic, activating the carbonized plastic with CO.sub.2, and performing cooling.

A passive valve for use as a fixed leak valve. The valve includes a body having an internal chamber, first and second body ports in fluid communication with the chamber with the first port configured for fluid communication with a patient connection and the second body port configured for fluid communication with a ventilator, a body passageway in fluid communication with the chamber and with ambient air exterior of the body, and a check valve seal positioned to seal the body passageway to permit the flow of gas within the chamber through the body passageway to the exterior of the body and to prevent the flow of ambient air exterior of the body through the body passageway into the chamber. In alternative embodiments, the valve is incorporated into the patient connection or constructed as a separate part connectable to the patient connection.

A passive valve for use as a fixed leak valve. The valve includes a body having an internal chamber, first and second body ports in fluid communication with the chamber with the first port configured for fluid communication with a patient connection and the second body port configured for fluid communication with a ventilator, a body passageway in fluid communication with the chamber and with ambient air exterior of the body, and a check valve seal positioned to seal the body passageway to permit the flow of gas within the chamber through the body passageway to the exterior of the body and to prevent the flow of ambient air exterior of the body through the body passageway into the chamber. In alternative embodiments, the valve is incorporated into the patient connection or constructed as a separate part connectable to the patient connection.

An adsorptive gas separation process and system is provided for separating at least a first component from a multi-component fluid mixture, or specifically for separating carbon dioxide from a combustion gas stream. The adsorptive gas separation process comprises an adsorbing step, a first regenerating step, an optional second regenerating step and an optional conditioning step.

The disclosure provides a method and system for extracting carbon dioxide from an exhaust gas. The method includes lowering a temperature of an exhaust gas using a heat exchanger, lowering a concentration of a particulate matter within the lowered temperature exhaust gas, and passing the lowered particulate concentration and lowered temperature exhaust gas through one or more membrane modules to produce a membrane module permeate flow that contains a higher concentration of carbon dioxide compared to a concentration of carbon dioxide in the lowered particulate concentration and lowered temperature exhaust gas. Further, the system includes a heat exchanger fluidly coupled to a particulate filter that is configured to lower a concentration of the particulate matter within the exhaust gas, and one or more membrane modules fluidly coupled to the particulate filter and configured to produce the membrane module permeate flow.

A system for processing biogas, the system comprising: a container, a pressure swing adsorption (PSA) unit housed in the container, the PSA unit having: a plurality of beds containing adsorbent material, the adsorbent material configured to selectively adsorb gas species from the biogas to process the biogas, a rotary valve module for distributing flow of 5 the biogas within the PSA unit, an inlet for supplying the biogas to the plurality of beds from outside of the container, and an outlet for transporting the processed biogas away from the PSA unit.

A method for producing oxygen from air using vacuum swing adsorption by means of a unit including at least two adsorbers each following, with an offset a pressure cycle, with a decompression step including at least a co-current first decompression sub-step for the partial balancing of pressure with the other adsorber which is performing counter-current recompression by means of a balancing valve, and, at least for one cycle out of three, a dead time sub-step which succeeds the first decompression sub-step, the method including a pressure of X bar at the end of the first decompression sub-step for the cycles that do not have a dead time sub-step, and a pressure of X bar at the end of the dead time sub-step, opening the balancing valve identically during the first decompression sub-step and the dead time sub-step, for the cycles that do have a dead time sub-step.

Methods of designing zeolite materials for adsorption of CO.sub.2. Zeolite materials and processes for CO.sub.2 adsorption using zeolite materials.

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.