A process and an apparatus for dehumidifying a moist gas mixture are provided. The apparatus for dehumidifying a moist gas mixture can be used and in the process. The absorption medium used in the process and the apparatus is also provided.

Systems and methods for selectively removing hydrogen sulfide from a feed gas stream. The systems include an absorber-heat exchanger (ABHEX) assembly configured to exchange thermal energy between a mixed stream and a thermal management fluid stream. The ABHEX assembly defines a mixed stream volume and a thermal management fluid stream volume. The ABHEX assembly includes an isolation structure that maintains fluid separation between the mixed stream and the thermal management fluid stream and facilitates thermal communication between the mixed stream and the thermal management fluid stream. The ABHEX assembly is configured to receive and to mix the feed gas stream and a lean solvent stream to generate the mixed stream, to separate the mixed stream into a product gas stream and a rich solvent stream, and to cool the mixed stream. The methods include methods of operating the systems.

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.

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.

Disclosed is a process for regenerating a hybrid solvent used to remove contaminants from a fluid stream and to provide an improved yield of purified fluid. Said process comprises a purification unit (12) and at least one regeneration unit (40) wherein make-up water (72) is added to the regenerated lean hybrid solvent (55) prior to reuse in the first purification unit and no water is recycled into the regeneration unit.

Methods for separation of oxygenates or other chemical components from fuels using chemical processes and separations including, but not limited to, onboard applications in vehicles. These separations may take place using a variety of materials and substances whereby a target material of interest is captured, held, and then released at a desired location and under desired conditions. In one set of experiments we demonstrated an enhancement in the separation of diaromatics by >38 times over gasoline and aromatics by >3.5 times over gasoline. This would give an advantage to reducing cold-start emissions, or emissions during transient conditions, in either gasoline or diesel.

A process for removing hydrogen sulfide from a sour gas stream is presented. The method oxidizes hydrogen sulfide to sulfuric acid by reducing aqueous bromine to hydrobromic acid in solution. The aqueous bromine solution does not react with hydrocarbon components common to natural gas including methane and ethane. This allows the process to both sweeten sour gas and convert its hydrogen sulfide content to sulfuric acid in a single step. In the present process, sulfuric acid is concentrated to eliminate its bromine content prior to being removed from the system, while the remaining hydrobromic acid solution is electrolyzed to regenerate aqueous bromine and produce hydrogen. Hydrobromic acid electrolysis requires less than half the energy required by water electrolysis and is an inherently flexible load that can shed or absorb excess power to balance supply and demand.

In an aspect, a method is disclosed that includes contacting a composition with an aqueous solution to yield a mixture, where the composition includes one or more of animal fats, animal oils, plant fats, plant oils, vegetable fats, vegetable oils, greases, and used cooking oil, about 5 wt. % or more of free fatty acids, about 10 wppm or more of total metals, about 8 wppm or more phosphorus, about 20 wppm or more of nitrogen, and the aqueous solution includes ((NH.sub.4).sub.2H.sub.2EDTA, (NH.sub.4).sub.4EDTA, a monoammonium salt of diethylenetriaminepentaacetic acid, a diammonium salt of diethylenetriaminepentaacetic acid, a triammonium salt of diethylenetriaminepentaacetic acid, a tetraammonium salt of diethylenetriaminepentaacetic acid, (NH.sub.4).sub.5DTPA, a combination of citric acid and Na.sub.4EDTA, a combination of citric acid and Na.sub.2H.sub.2EDTA, a combination of citric acid and a monosodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and a disodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and a trisodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and a tetrasodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and Na.sub.5DTPA, or a combination of any two or more thereof, where the method further includes centrifuging the mixture to yield a first treated composition, wherein the first treated composition has less total metals and less phosphorus than the composition.

The invention relates to a process and a plant for removing thiols from synthesis gas. Thiols and optionally thiophene and carbon disulfide are absorbed in a dedicated absorption stage with methanol as physical absorption medium. Methanol laden with at least thiols is freed of thiols in a stripping stage with methanol vapours as stripping gas and the methanol vapours-containing thiols are freed of methanol in a scrubbing stage. The process according to the invention minimizes methanol losses and the amounts of coolant required for the process.

An oxidation-reduction desulfurization system includes a reactor vessel with sour gas inlet at the bottom and a gas outlet at the top. A primary stage phase separator includes a vertically-oriented pipe with an inlet located inside the reactor vessel. The ratio of the reactor vessel diameter to the pipe inlet diameter is in a range of 2:1 to 5:1. Surface foam and non-gaseous multi-phase mixture including emulsion flow into a partially gas-filled upper section of the vertically-oriented pipe and freefall to a lower level, thereby facilitating mechanical breaking of the foam and the emulsion. A secondary stage phase separator connected to the gas outlet separates non-gaseous surge from sweet gas. Valves and a controller automatically maintain target levels of the non-gaseous multi-phase mixture and non-gaseous surge.