A process for treating effluent streams in a renewable transportation fuel production process is described. One or more of the sour water stream and an acid gas stream are treated directly in thermal oxidation section. The process allows the elimination or size reduction of a sour water stripper unit, waste water treatment plant, and sulfur recovery unit.

A method for decomposing a nitroso compound, comprising: adding an aqueous solution containing hydrogen halide to a liquid to be treated that contains the nitroso compound in such a manner that the hydrogen halide is present in an amount of 2 mol or more and 20 mol or less per mol of a nitroso group in the nitroso compound; and subsequently heating the resulting liquid to be treated at a temperature of not lower that 75° C. and not higher than a boiling point of water under ordinary pressure, thereby an amines are recovered.

In one embodiment, a carbon dioxide capturing system includes an absorber configured to include a first contact portion that brings a combustion exhaust gas containing carbon dioxide into contact with an absorbing liquid containing an amine compound, cause the absorbing liquid to absorb at least a portion of the carbon dioxide in the combustion exhaust gas at the first contact portion, and release the combustion exhaust gas. The system further includes a washing apparatus configured to include a second contact portion that brings the combustion exhaust gas released from the first contact portion of the absorber into contact with a washing liquid, and configured such that the combustion exhaust gas and the washing liquid are individually fed to an upstream side of the second contact portion.

An acid-gas capturing apparatus according to an embodiment includes an absorption unit configured to discharge an absorption-unit exhaust gas, and a regeneration unit configured to discharge a regeneration unit exhaust gas. The regeneration unit exhaust gas is compressed in a compression unit. The absorption-unit exhaust gas or the regeneration unit exhaust gas before it is compressed by the compression unit is cleaned in a first cleaning unit by means of a first cleaning liquid. A compression-condensate liquid, which is generated by the compression of the regeneration unit exhaust gas in the compression unit, is mixed into the first cleaning liquid through a first compression-condensate-liquid line whose one end is connected to the compression unit.

Various illustrative embodiments of a system and process for recovering high-quality biomethane and carbon dioxide product streams from biogas sources and utilizing or sequestering the product streams are provided. The system and process synergistically yield a biomethane product which meets gas pipeline quality specifications and a carbon dioxide product of a quality and form that allows for its transport and sequestration or utilization and reduction in greenhouse gas emissions. The system and process result in improved access to gas pipelines for products, an improvement in the carbon intensity rating of the methane fuel, and improvements in generation of credits related to reductions in emissions of greenhouse gases.

A CO.sub.2 separation/recover method in cement production exhaust gas has a step of harmful component removal that removes an acidic component and a harmful component from exhaust gas discharged from a cement production facility; and a step of CO.sub.2 separation and recover that separates and recovers CO.sub.2 by bringing the exhaust gas from which the acidic component and the harmful component are removed into contact with a CO.sub.2 absorption material, so that the acidic component and the harmful component are removed before separating and recovering CO.sub.2, resulting in deterioration of the absorbing ability of the CO.sub.2 absorption material being suppressed; and the cement production exhaust gas can be appropriately disposed.

A solvent system for the removal of acid gases from mixed gas streams is provided. Also provided is a process for removing acid gases from mixed gas streams using the disclosed solvent systems. The solvent systems may be utilized within a gas processing system.

In one embodiment, a carbon dioxide capturing system includes an absorber to absorb CO2 from first gas into lean liquid, and produce rich liquid that is the lean liquid absorbing the CO2 and second gas that is the first gas removing the CO2, and a regenerator to separate third gas including the CO2 from the rich liquid flowing from the absorber, and provide the lean liquid and the third gas. The system further includes a flowmeter to measure a flow rate of the third gas, a liquid level gauge to measure a liquid level of the lean liquid and/or the rich liquid, and a controller to regulate a quantity of heat energy supplied to the regenerator based on the flow rate of the third gas, and regulate a total amount of the lean liquid and the rich liquid in the system based on the liquid level.

Provided is a method for upgrading a bio-based material, the method including the steps of pre-treating bio-renewable oil(s) and/or fat(s) to provide a bio-based fresh feed material, hydrotreating the bio-based fresh feed material, followed by separation, to provide a bio-propane composition.

A system and method to both reduce interior levels of volatile organic compounds and carbon dioxide that is more energy efficient than increasing building ventilation rates. The system comprises a carbon dioxide scrubber that operates in a continuous manner, and optionally but preferably further comprises an air purifier.