The composite amine absorbing solution according to the present invention absorbs CO.sub.2 or H.sub.2S or both in a gas, and is obtained by dissolving a linear monoamine, a diamine, and an amide group-containing compound in water. By adopting this composite amine absorbing solution, the composites are interacting in a composite manner, due to an integrated effect of the components, the absorption property of CO.sub.2 or H.sub.2S or both is favorable, the desorption properties of the CO.sub.2 or H.sub.2S absorbed when regenerating the absorbing solution become favorable, and the amount of steam from a reboiler used when regenerating the absorbing solution in a CO.sub.2 recovery device can be reduced.

A process for the removal of CO.sub.2 from flue gases using a co-current flow absorption column followed by one or more serial osmotic filters. The permeate is heated to strip out the CO.sub.2. Both sides of the filters are fed back to the column input.

Disclosed herein are methods of electrochemically enhanced amine-based CO.sub.2 capture and systems for performing the methods of amine-based CO.sub.2 capture. The present methods and systems advantageously may be carried out at ambient temperatures and allow for reusing the amine through multiple cycles.

Reclaimer systems and methods of their use are provided. Reclaimer systems use one or more fluid input streams and a variable steam input to control temperature of a fluid in a reclaimer vessel. In certain embodiments, a temperature controller and level controller are both connected to at least one fluid input stream subsystem and a steam input subsystem. Output from the level controller and the temperature controller is used to control flow through both a fluid input stream subsystem and a steam input subsystem. In certain embodiments, selectors are used to determine which controller output to obey when controlling the steam input subsystem and the fluid input stream subsystem. In certain embodiments, lean amine agent and an inert fluid are input in a ratio controlled by a ratio controller in order to maintain the fluid level in a vessel.

A method of increasing the overall mass transfer rate of acid gas scrubbing solids is disclosed. Various catalyst compounds for that purpose are also disclosed.

A compound of the general formula (I) ##STR00001##
in which R.sub.1, R.sub.2 and R.sub.3 are independently selected from C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.4 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.5 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; m is 2, 3, 4 or 5; n is 2, 3, 4 or 5; and o is an integer from 0 to 10. A preferred compound of the formula (I) is 2-(2-tert-butylaminoethoxy)ethylamine. Absorbents comprising a compound of the formula (I) have rapid absorption of carbon dioxide from fluid streams and are also suitable for processes for the simultaneous removal of H.sub.2S and CO.sub.2, where given H.sub.2S limits have to be observed but complete removal of CO.sub.2 is not required.

A process for removing C.sub.5-C.sub.8-hydrocarbons and acid gases from a fluid stream is described, where a) the fluid stream is brought into contact with an absorption medium comprising at least one amine in an absorption zone to obtain a deacidified fluid stream and an acid-gases-laden absorption medium, b) the laden absorption medium is heated in a first heat exchanger and decompressed into a decompression zone to a pressure of from 5 to 10 bar to obtain a C.sub.5-C.sub.8-hydrocarbons-comprising gas phase and a hydrocarbon-depleted laden absorption medium, c) the hydrocarbon-depleted laden absorption medium is heated in an optional second heat exchanger and passed into a stripper in which at a pressure of 1 to 2.5 bar the acid gases are at least partially liberated by supplying heat to obtain a regenerated absorption medium and an acid-gas-comprising stream, and d) the regenerated absorption medium is recycled into the absorption zone.

A method of generating electricity from an amine-based acid gas capture process using an electrolytic cell containing an anode and a cathode and an amine based electrolyte comprising: contacting a metal based redox material with an amine based electrolyte in the presence of an anode to form a metal-ammine complex in solution; adding an absorbed or absorbable acid gas to the metal-ammine complex containing electrolyte to form an acid gas absorbed electrolyte; and contacting the acid gas absorbed electrolyte with a cathode deposit, wherein the acid gas breaks up the metal-ammine complex in the metal-ammine complex containing electrolyte thereby generating a potential difference between the anode and the cathode.

An apparatus and a combined process for carbon dioxide gas separation, combining the hydrate-based process with the chemical absorption process, which reduces secondary pollution and allows the efficient continuous separation of carbon dioxide gas without increasing the pressure and thereby the operating cost is reduced significantly. The apparatus and combined process can be applied in the separation of carbon dioxide in IGCC synthetic gas, natural gas and biogas, and address the issues of the existing processes such as high energy consumption, low throughput, and secondary pollution.

Methods for removing oxyanions from water according to the following steps: (i) dissolving an oxyanion precipitating compound into the aqueous source to result in precipitation of an oxyanion salt of the oxyanion precipitating compound; and (ii) removing the oxyanion salt from the water containing the oxyanion to result in water substantially reduced in concentration of the oxyanion; wherein the oxyanion precipitating compound has the following composition:

##STR00001##

wherein A is a ring-containing moiety and X.sup.m is an anionic species with a magnitude of charge m. The invention employs bis-iminoguanidinium compounds according to Formula (1a) as well as neutral precursor compounds according to Formula (1), which can be used for removing undesirable species from aqueous solutions or air, such as removal of sulfate from water and carbon dioxide from air.