This disclosure is related to systems, methods, apparatuses, and techniques for generating water using waste heat. In certain embodiments, a system includes a water generating unit and a waste-heat-generating-system. The water generating unit can be configured to generate the water and comprises a desiccation device and a condenser coupled to the desiccation device. The waste-heat-generating-system can generate the waste heat when operating or is use. The water generating unit can be configured to use waste heat generated by the waste-heat-generating-system to generate the water.

The present disclosure is directed to the integration of direct air capture of carbon dioxide with thermochemical water splitting, the latter optionally driven by solar energy. The disclosure is also directed to a process comprising extracting carbon dioxide from an air stream by contacting the air-stream with an alkali metal ion-transition metal oxide of empirical formula A.sub.xMO.sub.2 (0.1<x≤1), where A represents the alkali metal ion comprising sodium ion, potassium ion, or a combination thereof and M comprises iron, manganese, or a combination thereof to form a transition metal composition comprising an oxidized ion extracted-transition metal oxide.

There are provided methods for treating a gas having an undesirable odor. The methods comprise contacting the gas with an acidic aqueous oxidizing composition having a pH of about 2.0 to about 3.0 and comprising at least one cation of a metal; a sequestering agent; and H.sub.2O.sub.2 and submitting the gas and the composition to UV radiation when the gas and the composition are contacting each other, wherein the treatment permits to reduce by at least 60% intensity of the undesirable odor.

A method and apparatus for purifying gas where gas is treated in a multistage treatment having at least two ejector stages, a motive medium including liquid, steam or gaseous agent at high pressure injected by an ejector of the ejector stage, and the gas is sucked into the same ejector and mixed with the motive medium for forming a mixture, at least a part of gas and/or liquid phase of the mixture is supplied to a second ejector stage having so that a second motive medium which includes liquid, steam or gaseous agent is injected to the ejector and the gas and/or the liquid phase is sucked into the same ejector in which the gas and/or liquid phase is mixed with the second motive medium for forming a second mixture, at least one of the mixtures includes an additive for removing impurities of the gas, and a purified gas is formed.

A carbon dioxide capture facility is disclosed comprising packing formed as a slab, and at least one liquid source. The slab has opposed dominant faces, the opposed dominant faces being at least partially wind penetrable to allow wind to flow through the packing. The at least one liquid source is oriented to direct carbon dioxide absorbent liquid into the packing to flow through the slab. The slab is disposed in a wind flow that has a non-zero incident angle with one of the opposed dominant faces. A method of carbon dioxide capture is also disclosed. Carbon dioxide absorbing liquid is applied into packing in a series of pulses. A gas containing carbon dioxide is flowed through the packing to at least partially absorb the carbon dioxide from the gas into the carbon dioxide absorbing liquid.

Described herein is a dry sorbent injection system and process for removing sulfur oxides from a flue gas. The process generally comprises treating the flue gas with a dry sorbent material to convert the sulfur oxides to sodium sulfate particulates. The sodium sulfate particulates may then be introduced into a mix tank with water to form sodium sulfate solution. The sodium sulfate solution may then be reacted with a calcium hydroxide slurry to produce a reaction mixture comprising calcium sulfate precipitate and a sodium hydroxide solution. The calcium sulfate (gypsum) may be recovered, and the sodium hydroxide solution may be recirculated to pre-treat the flue gas by removing at least a portion of the sulfur dioxide and/or cooling the flue gas stream.

An ocean alkalinity enhancement (OAE) system that reduces atmospheric CO.sub.2 and mitigates ocean acidification by electrochemically processing feedstock solution (e.g., seawater or brine) to generate an alkalinity product that is then supplied to the ocean. The OAE system includes a base-generating device and a control circuit disposed within a modular system housing deployed near a salt feedstock. The base-generating device (e.g., a bipolar electrodialysis (BPED) system) generates a base substance that is then used to generate the ocean alkalinity product. The control circuit controls the base-generating device such that the alkalinity product is supplied to the ocean only when (1) sufficient low/zero-carbon electricity is available, (2) it is safe to operate the base-generating device, and (3) supplying the alkalinity product will not endanger sea life. Modified BPED systems include features that facilitate autonomous system operations including enhanced maintenance cycle operations and a reduced reliance on external fresh water sources.

An emissions clean-up process is provided to remove detrimental exhaust gases from a fossil fuel power plant and to produce and/or reclaim various useful commercial byproducts. The process includes mixing a blended liquid solution with a solubilizer in a mixing tank to create a chemical reaction therein to produce an ionic solid and an alkaline liquid solution. By mixing various blended solutions with desired solubilizers, alkaline liquids are produced which may be chemically combined to create other byproducts or sold commercially. Likewise, the alkaline liquids may be passed through a wet scrubber to create a byproduct that when chemically mixed with an acid creates desired byproducts. Other byproducts such as a sodium bicarbonate liquid solution exits the wet scrubber and is sold or used in the subject process to produce various other byproducts.

A method for producing a synthetic fuel from hydrogen and carbon dioxide comprises extracting hydrogen molecules from hydrogen compounds in a hydrogen feedstock to produce a hydrogen-containing fluid stream; extracting carbon dioxide molecules from a dilute gaseous mixture in a carbon dioxide feedstock to produce a carbon dioxide containing fluid stream; and processing the hydrogen and carbon dioxide containing fluid streams to produce a synthetic fuel. At least some thermal energy and/or material used for at least one of the steps of extracting hydrogen molecules, extracting carbon dioxide molecules, and processing the hydrogen and carbon dioxide containing fluid streams is obtained from thermal energy and/or material produced by another one of the steps of extracting hydrogen molecules, extracting carbon dioxide molecules, and processing the hydrogen and carbon dioxide containing fluid streams.

A process for hydrotreating a feed stream comprising a biorenewable feedstock is disclosed. The process comprises hydrotreating the feed stream in the presence of a hydrotreating hydrogen stream and a hydrotreating catalyst to provide a hydrotreated stream. The hydrotreated stream is separated into a hydrotreated liquid stream and a hydrotreated gas stream. The hydrotreated liquid stream is subjected to stripping to provide a stripper off-gas stream. At least a portion of the stripper off-gas stream is contacted with a caustic stream to provide a sulfur-lean gas stream and a sulfur-rich caustic stream. The sulfur-rich caustic stream is further treated to provide a treated gas stream.