A method of treating a metal carbonate salt includes hydrolyzing a metal halide salt to form a hydrohalic acid and a hydroxide salt of the metal in the metal halide salt. The metal includes an alkaline earth metal or an alkali metal. The method includes reacting the hydrohalic acid with the metal carbonate salt, wherein the metal carbonate salt is a carbonate salt of the alkaline earth metal or alkali metal, to form CO.sub.2 and the metal halide salt. At least some of the metal halide salt formed from the reacting of the hydrohalic acid with the metal carbonate salt is recycled as at least some of the metal halide salt in the hydrolyzing of the metal halide salt to form the hydrohalic acid and the hydroxide salt.

This disclosure provides an apparatus to manipulate the crystal morphology of a powder to improve the flow of a powder from a vessel and/or flowability of a powder in order to achieve stable fluidization of the powder within a vessel.

The removal of carbon dioxide using sequestration materials that include salts in molten form, and related systems and methods, are generally described.

A method for managing and controlling nitrogen emission from a cyclic liquor flow system in a pulp mill (1), the pulp mill (1) comprising a recovery system (20) for recovering heat and chemicals from a pulping process (30), the recovery system (20) comprising a recovery boiler (8) and a nitrogen oxide scrubber (15), the nitrogen oxide scrubber (15) being arranged to remove nitrogen oxide from flue gas (16) from the recovery boiler (8), the method comprising the steps of: —exposing flue gas (16) from the recovery oiler (8) to an oxidizing agent, thereby oxidising nitrogen oxide in the flue gas (16) to higher nitrogen oxides; —contacting the flue gas (16) with an alkaline aqueous scrubber liquid (17) in the nitrogen oxide scrubber (15), thereby absorbing the nitrogen oxides in the scrubber liquid (17) and producing a nitrogen containing scrubber liquid (17); —introducing all or a part of the nitrogen containing scrubber liquid (17) into the cyclic liquor flow system. An arrangement for managing and controlling nitrogen emission from a cyclic liquor flow system in a pulp mill (1) is also disclosed.

A system for producing gas streams for use in synthetic fuel production through CO2 capture and water splitting is disclosed. The system includes a CO2 capture device configured to receive a CO2-containing stream and including an aqueous alkaline solution. The alkaline solution includes hydroxide and/or carbonate ions. The CO2 capture device generates a carbon-rich solution when the alkaline solution absorbs CO2. The carbon-rich solution includes carbonate and/or bicarbonate ions. The system also includes an electrolyzer fluidically coupled to the CO2 capture device, and defining a volume including an anode region having an anode, and a cathode region having a cathode. The volume includes an electrolyte solution having a pH gradient generated by an electric current, causing the electrolyte solution to be acidic in the anode region and alkaline in the cathode region. The carbon-rich solution is received into the electrolyzer. The electrolyzer generates hydrogen, oxygen, and CO2 streams.

The present disclosure is directed to systems and methods of providing a mixed-gas inhalant to a patient via a gas recirculation loop. The gas recirculation loop receives a first mixed-gas exhalant having a first carbon dioxide concentration from the patient, one or more carbon dioxide removal devices discharge a second mixed-gas exhalant having a second carbon dioxide concentration that is less than the first carbon dioxide concentration. The second mixed-gas exhalant is combined with a mixed-gas supply to provide a mixed-gas inhalant. The mied-gas supply includes a first gas and a second gas. The mixed-gas supply is pressure and flow controlled to produce a mixed-gas inhalant having a defined composition delivered to the patient at a defined volumetric flow rate. The first gas may include a gas containing oxygen and the second gas may include a gas mixture containing a noble or inert gas and oxygen.

The present disclosure provides systems and methods useful in capture of one more moieties (e.g., carbon dioxide) from a gas stream (i.e., direct air capture). In various embodiments, the systems and methods can utilize at least a scrubbing unit, a regeneration unit, and an electrolysis unit whereby an alkali solution can be used to strip the moiety (e.g., carbon dioxide) from the gas stream, the removed moiety can be regenerated and optionally purified for capture or other use, and a formed salt can be subjected to electrolysis to recycle the alkali solution back to the scrubber for re-use with simultaneous production of one or more further chemicals.

This disclosure relates to improved methods for alkali metal cyanide production, particularly to improved methods for sodium cyanide production. The improved method of producing sodium cyanide involves the step of contacting hydrogen cyanide with an aqueous solution of sodium carbonate or of a mixture of sodium carbonate and sodium bicarbonate to produce a sodium cyanide solution.

This disclosure provides a method for treating natural gas comprising causing at least some of a sour natural gas stream comprising hydrocarbon gas and hydrogen sulfide to contact an amine or pass through a separation system. A sweet natural gas stream comprising hydrocarbon gas and a waste gas stream comprising hydrogen sulfide are formed by contacting the sour natural gas with an amine or by passing it though a separation device. At least some of the hydrogen sulfide in the waste gas stream is oxidized, forming an exhaust gas stream comprising sulfur dioxide, which is then contacted with water or reactant and water solution or slurry to destroy or convert SO.sub.2 into a less environmentally harmful compound.

Methods of sequestering carbon dioxide (CO.sub.2) are provided. Aspects of the methods include contacting a CO.sub.2 containing gaseous stream with an aqueous medium under conditions sufficient to produce a bicarbonate rich product. The resultant bicarbonate rich product (or a component thereof) is then combined with a cation source under conditions sufficient to produce a solid carbonate composition and product CO.sub.2 gas, followed by injection of the product CO.sub.2 gas into a subsurface geological location to sequester CO.sub.2. Also provided are systems configured for carrying out the methods.