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.

A method for generating Renewable Natural Gas (RNG) from raw biogas is disclosed, in which carbon dioxide is removed from biogas to generate pipeline specification RNG by a combination of absorption and membrane processes. The absorption process provides for the initial bulk carbon dioxide removal. The membrane process provides for the simultaneous removal of carbon dioxide and water vapors to pipeline specification. The method is characterized by a reduced separation energy consumption as compared to stand-alone membrane and absorption unit separations for biogas upgrading.

A gas treatment method includes an absorption step in which a gas to be treated containing an acidic compound, such as carbon dioxide, is brought into contact, in an absorber, with a treatment liquid that absorbs the acidic compound; and a regeneration step in which the treatment liquid, having the acidic compound absorbed therein, is sent to a regenerator, and the treatment liquid is then heated to separate the acidic compound from the treatment liquid. In the regeneration step, a gas almost insoluble to the treatment liquid, such as hydrogen gas, is brought into contact with the treatment liquid.

A process for absorbing carbon dioxide from a gas stream containing carbon dioxide, including the steps of contacting the gas stream with an aqueous composition including a substituted heteroaromatic compound having a six-membered heteroaromatic ring with from 1 to 3 nitrogen atoms in the heteroaromatic ring and at least one substituent wherein at least one of the substituents is of formula —R.sup.1NH.sub.2 wherein R.sup.1 is selected from C.sub.1 to C.sub.6 alkylene and ethers of formula —R.sup.2—O—R.sup.3— wherein R.sup.2 and R.sup.3 are C.sub.1 to C.sub.3 alkylene

A particulate material for removing an acid gas and/or mercury contaminant from a hydrocarbon gas is disclosed. The particulate material comprises a superabsorbent hydrogel comprising a cross-linked hydrophilic polymer network having from 0.1 mol % to 50 mol % cross-linking agent. The superabsorbent hydrogel has one or more compounds capable of binding the acid gas and/or mercury contaminant incorporated into the hydrophilic polymer network by absorbing said one or more compounds as a liquid phase or an aqueous solution. Methods for preparing the particulate material and using the particulate material to remove one or more acid gas and/or mercury contaminants from a hydrocarbon gas, dehydrating the hydrocarbon gas, and mitigating corrosion in gas flowlines are also disclosed.

Systems and methods for preventing formation of carbonyl sulfide in the production of sweet gas using an amine-lean aqueous solution and metal oxide adsorbent material. In embodiments, a method may include producing, via an amine absorption column supplied with a raw gas stream that includes fractions of hydrogen sulfide (H.sub.2S), carbon dioxide (CO.sub.2), and carbon monoxide (CO), (1) a sweet gas stream that includes the fractions of the CO and (2) an amine-rich aqueous solution that includes the H.sub.2S and CO.sub.2. The method may include heating the amine-rich aqueous solution to produce a heated amine-rich aqueous solution. The method may include producing, via an amine regenerator supplied with the heated amine-rich aqueous solution (1) an acid gas stream that includes the H.sub.2S and CO.sub.2 and (2) an amine-lean aqueous solution. The method may include producing, via adsorption in a metal oxide adsorbent vessel, an effluent stream that includes the CO.sub.2.

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.

A process for absorbing carbon dioxide from a gas stream containing carbon dioxide, including the steps of contacting the gas stream with an aqueous composition including a substituted heteroaromatic compound having a six-membered heteroaromatic ring with from 1 to 3 nitrogen atoms in the heteroaromatic ring and at least one substituent wherein at least one of the substituents is of formula —R.sup.1NH.sub.2 wherein R.sup.1 is selected from C.sub.1 to C.sub.6 alkylene and ethers of formula —R.sup.2—O—R.sup.3— wherein R.sup.2 and R.sup.3 are C.sub.1 to C.sub.3 alkylene.

A system for carbon dioxide capture from a gas mixture comprises an absorber that receives a lean solvent system stream (containing a chemical solvent, physical-solvent, and water) from the stripper, a stripper that receives the rich solvent stream from the absorber and produces the product carbon dioxide and the lean solvent through the use of a reboiler in fluid communication with a lower portion of the stripper, a condenser in fluid communication with a vapor outlet of the stripper, a cross-exchanger in fluid communication with a rich solvent system outlet from the absorber and a rich solvent system inlet on the stripper, and a splitter. The splitter is configured to separate the rich solvent system stream into a first portion and second portion, where the first portion directly passes to the stripper and the second portion passes through the cross-exchanger prior to passing to the stripper.

Embodiments of a composition of the present invention for scavenging sulfides from hydrocarbon fluids and water generally include diaminol/diaminacetal provided in a chemical system, wherein the diaminol/diaminacetal is prepared by reacting one molar equivalent of glyoxal and two molar equivalents of a primary amine functionality. In various embodiments, the chemical system includes at least one component selected from surfactants, hydrotropes, alcohols, amines, amino acids, and ethers. Embodiments of a method for scavenging sulfides from hydrocarbon fluids and water is also provided.