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 at least one purification unit (12) and at least one regeneration unit (40) wherein condensed water 62 from the regeneration unit is recycled back into the purification unit and none of the condensed water is reintroduced into the regeneration unit.

A degradant concentration measurement device 14 according to the invention has an electric conductivity measurement instrument 71A measuring the electric conductivity of a lean solution 16 that is an acidic gas-absorbing solution and detection means 72 obtaining the concentration of a degradant contained in a lean solution 16 from the measured electric conductivity of the lean solution 16 based on the relationship between the previously-obtained electric conductivity of the lean solution 16 and the concentration of the degradant contained in the lean solution 16.

A method for treating liquefied hydrocarbons including acid gases to remove said acid gases while minimizing loss of amine species, said method comprising the steps of contacting the liquefied hydrocarbons with an absorbent aqueous solution of a first amine compound, the first amine compound having the structure: ##STR00001##
wherein R.sub.1 is propane-2,3-diol; R.sub.2 is hydrogen, methyl ethyl, 2-hydroxyethyl, or propane-2,3-diol; and R.sub.3 is hydrogen, methyl, ethyl, 2-hydroxyethyl or propane-2,3-diol.

The rate of recovery of a purification target gas from a gas purification apparatus that uses a PSA device is improved, and both a high purity and a high recovery rate are achieved with good power efficiency. The present invention is directed to a gas purification method using the PSA method, in which a carbon molecular sieve having a pore volume, at a pore diameter of 0.38 nm or more, of not exceeding 0.05 cm.sup.3/g and a pore volume, at a pore diameter of 0.34 nm, of 0.15 cm.sup.3/g or more, in a pore diameter distribution measured by the MP method is used as an adsorbent, and, in an adsorption step, a miscellaneous gas is adsorbed from a source gas by bringing the source gas into contact with the adsorbent for 10 seconds or more and 6000 seconds or less so as to obtain a concentrated methane.

The present invention relates to an aqueous alkanolamine solution demonstrating low volatility comprising 2-di-methylamino-2-hydroxymethyl-1, 3-propanediol useful for removing acid gases from gaseous mixtures. Said aqueous alkanolamine solution may further comprise one or more of an acid or acid-forming compound, another amino compound, an activator, a physical solvent, or one or more other compounds used in gal-liquid treatment practices. Further, the present invention relates to a process for removing acid gases from a gaseous mixture, preferably hydrogen sulfide, comprising the step of contacting the gaseous mixture with said aqueous alkanolamine solution. Examples of the gaseous mixtures include natural gas, synthesis gas, tail gas, and refinery gas.

Methods of reducing acid gas from a stream, comprising contacting the stream with a solvent system comprising a glycerol derivative are described herein. Disclosed herein is a composition comprising a glycerol derivative and an acid gas. A method for sweetening a natural gas stream comprising contacting a solvent system comprising a glycerol derivative with a natural gas stream is described herein.

Systems comprising a composition where an imidazole is tethered to an amine and a solvent are described herein. Methods of their preparation and use are also described herein. The methods of using the systems include the reduction of volatile compounds from gas streams and a liquid stream.

Processes and systems for upgrading natural gas liquids. At least a portion of the natural gas liquid components in a shale gas stream can be dehydrogenated to their corresponding olefin derivatives prior to separating any methane from the liquids. Further processing subsequent to dehydrogenation could include various separations, oligomerizing olefins produced in the dehydrogenation step, recovering desired products, etc. The order of the processing steps subsequent to dehydrogenation could be adjusted in various cases.

A process for removal of acid gases from fluid stream, wherein the fluid stream is brought into contact with an absorbent to obtain a treated fluid stream and a laden absorbent, the absorbent comprising a diluent and a compound of the general formula (I) wherein R.sup.1 is selected from C.sub.1-C.sub.8-alkyl and C.sub.2-C.sub.8-hydroxyalkyl; R.sup.2 is selected from hydrogen and C.sub.1-C.sub.8-alkyl; R.sup.3 is selected from hydrogen and C.sub.1-C.sub.8-alkyl; R.sup.4 is selected from hydrogen and C.sub.1-C.sub.8-alkyl; R.sup.5 is C.sub.1-C.sub.8-alkyl; with the proviso that at least one of the following conditions (i) and (ii) is met: (i) R.sup.5 is C.sub.3-C.sub.8-alkyl bound to the nitrogen atom via a secondary or tertiary carbon atom; (ii) when R.sup.4 is hydrogen, R.sup.3 is C.sub.1-C.sub.8-alkyl; or when R.sup.4 is C.sub.1-C.sub.8-alkyl, at least one of R.sup.2 and R.sup.3 is C.sub.1-C.sub.8-alkyl; and n is an integer from 0 to 6. Further provided is an absorbent for the absorption of acid gases from a fluid stream, comprising a diluent and a compound of the general formula (I) as defined above, as well as the use of a compound of the general formula (I) as defined above for removal of acid gases from a fluid stream. The absorbents are useful for the selective removal of hydrogen sulfide from fluid streams and have high acid gas loading capacity, high stability, and low volatility.

##STR00001##

A natural gas pretreatment system includes: a carbon dioxide removal unit configured to remove carbon dioxide from the natural gas by bringing an absorption liquid and the natural gas into contact with each other; and a water removal unit configured to remove water by causing the natural gas to flow through a packed bed containing a water adsorbent. The packed bed contains a carbon dioxide adsorbent for adsorbing and removing the carbon dioxide that has not been completely removed in the carbon dioxide removal unit, and a concentration of the carbon dioxide contained in the natural gas is measured by an outlet-side carbon dioxide measurement unit on an outlet side of the water removal unit.