A method of dehydrating a hydrocarbon gas stream including stripping water from a liquid desiccant stream using a water-undersaturated portion of the gas stream, drying the gas stream to extract the stripped water, and then further drying the partially-dried gas stream using the stripped desiccant to achieve a low water content level in the gas stream for pipeline transportation. In one embodiment, the liquid desiccant is supplied by a regeneration facility at a remote location and the liquid desiccant is returned to the regeneration facility for regeneration after drying the gas. In another embodiment, the regeneration of the desiccant is performed locally whereby the liquid desiccant is, after drying the gas, stripped again of water and reused locally.

The invention provides a method for generating a solid wood-based material and a hemicellulose-derived material from a wood raw material. The method includes treating the wood raw material under aqueous conditions at elevated temperature and pressure to generate a hemicellulose-containing fluid component and a solid component; separating the fluid component from the solid component; processing at least a part of the solid component into a solid wood-based material; and processing the liquid component into a hemicellulose-derived material. The invention also provides for a wood-derived fuel with a low ash content.

The disclosure provides compositions and methods that are useful in removing, lowering, or otherwise controlling hydrogen sulfide and mercaptans. The compositions and methods can be used in any industry where hydrogen sulfide poses problems, such as when dealing with crude oil based, natural gas based, and/or coal based products. In some embodiments, the compositions include one or more alkoxylated amino formaldehyde adducts.

Certain functionalized aldehydes scavengers may be used to at least partially scavenge sulfur-containing contaminants from fluid systems containing hydrocarbons and/or water. The contaminants scavenged or otherwise removed include, but are not necessarily limited to, H.sub.2S, mercaptans, and/or sulfides. Suitable scavengers include, but are not necessarily limited to, reaction products of glycolaldehyde with aldehydes; reaction products of glycolaldehyde with a nitrogen-containing reactant (e.g. an amine, a triazine, an imine, an aminal, and/or polyamines); non-nitrogen-containing reaction products of a hydrated aldehyde with certain second aldehydes; reaction products of 1,3,5-trioxane with hydroxyl-rich compounds (e.g. glyoxal, polyethylene glycol, polypropylene glycol, pentaerythritol, and/or sugars); and reaction products of certain aldehydes with certain phenols; and combinations of these reaction products.

Disclosed herein are scavenging compounds and compositions useful in applications relating to the production, transportation, storage, and separation of crude oil and natural gas. Also disclosed herein are methods of using the compounds and compositions as scavengers, particularly in applications relating to the production, transportation, storage, and separation of crude oil and natural gas.

Multiple risers are provided to perform different steps in a biogas water wash process. The risers may include absorption risers, flashing risers, and stripping risers. In each riser, the inlets to provide fluids to the riser and outlets to remove fluids from the risers are provided at one end of the riser. Each riser may then be located substantially below grade such that the end with the inlets and outlets is accessible at or just above the ground level. The risers within each step of the water wash process may be connected in series, parallel, or a combination thereof. The risers may also be constructed of a polyethylene material to reduce cost and weight of the water wash system.

A process for separating a mixed or raw gas feed to produce a dry gas product and a hydrocarbon liquid product is provided. The process comprises scrubbing heavier hydrocarbon components from the gas feed to produce a lighter ends gas stream and a heavier ends liquid stream; cooling the lighter ends gas stream and separating the cooled lighter ends gas stream into a cold liquid stream and the dry gas product; and using the cold liquid stream to assist in scrubbing the heavier hydrocarbon components from the gas feed.

An absorbent for selective removal of hydrogen sulfide over carbon dioxide from a fluid stream comprises an aqueous solution of a) a tertiary amine, b) a sterically hindered secondary amine of the general formula (I)

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in which R.sub.1 and R.sub.2 are each independently selected from C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are each independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl, with the proviso that at least one R.sub.4 and/or R.sub.5 radical on the carbon atom bonded directly to the nitrogen atom is C.sub.1-4-alkyl or C.sub.1-4-hydroxyalkyl when R.sub.3 is hydrogen; x and y are integers from 2 to 4 and z is an integer from 1 to 4; where the molar ratio of b) to a) is in the range from 0.05 to 1.0, and c) an acid in an amount, calculated as neutralization equivalent relative to the protonatable nitrogen atoms in a) and b), of 0.05 to 15.0%. One preferred amine of the formula I is 2-(2-tert-butylaminoethoxy)ethanol. The absorbent allows a defined H.sub.2S selectivity to be set at pressures of the kind typical in natural gas processing.

Hydrocarbon gas treatment systems and methods. The hydrocarbon gas treatment systems include a feed gas supply system configured to provide a feed gas stream and a hydrogen sulfide removal system configured to separate the feed gas stream into a product gas stream and an acid gas stream. The hydrocarbon gas treatment systems also include a heat exchanger configured to cool the acid gas stream to generate a cooled acid gas stream and an acid gas enrichment system configured to separate the cooled acid gas stream into a treated gas stream and an enriched acid gas stream. The methods include providing a feed gas stream, separating the feed gas stream into a product gas stream and an acid gas stream, cooling the acid gas stream to generate a cooled acid gas stream, and separating the cooled acid gas stream into a treated gas stream and an enriched acid gas stream.

Certain functionalized aldehydes scavengers may be used to at least partially scavenge sulfur-containing contaminants from fluid systems containing hydrocarbons and/or water. The contaminants scavenged or otherwise removed include, but are not necessarily limited to, H.sub.2S, mercaptans, and/or sulfides. Suitable scavengers include, but are not necessarily limited to, reaction products of glycolaldehyde with aldehydes; reaction products of glycolaldehyde with a nitrogen-containing reactant (e.g. an amine, a triazine, an imine, an aminal, and/or polyamines); non-nitrogen-containing reaction products of a hydrated aldehyde with certain second aldehydes; reaction products of 1,3,5-trioxane with hydroxyl-rich compounds (e.g. glyoxal, polyethylene glycol, polypropylene glycol, pentaerythritol, and/or sugars); and reaction products of certain aldehydes with certain phenols; and combinations of these reaction products.