The present invention relates to methods for selective binding, selective membrane transport and storage of carbon dioxide (CO.sub.2) in aqueous media. The method of the present invention comprises providing an aqueous acceptor solution containing at least one acceptor compound having a free guanidino and/or amidino group, which is contacted with a gas containing carbon dioxide to bind the carbon dioxide in the acceptor solution. The acceptor solutions containing bound carbon dioxide obtained thereby are useful for storing carbon dioxide in aqueous media, for again releasing the carbon dioxide, and for use in electrochemical processes, such as electrodialysis, to selectively transport bound carbon dioxide through separation membranes into aqueous media. The present invention further relates to the preparation of carbonates starting from acceptor solutions containing bound carbon dioxide.

An energy conversion system includes a fuel synthesis device, an H.sub.2O supply unit, a CO.sub.2 supply unit, and a supply control unit. The fuel synthesis device includes an electrolyte, and a pair of electrodes provided on both sides of the electrolyte. The H.sub.2O supply unit supplies H.sub.2O to the fuel synthesis device. The CO.sub.2 supply unit supplies CO.sub.2 to the fuel synthesis device. The supply control unit controls a supply of H.sub.2O and a supply of CO.sub.2. The fuel synthesis device electrolyzes H.sub.2O and CO.sub.2 using external electric power, and synthesizes a hydrocarbon using H.sub.2 and CO generated by electrolysis. The supply control unit starts the supply of H.sub.2O to the fuel synthesis device by the H.sub.2O supply unit after the supply of CO.sub.2 to the fuel synthesis device by the CO.sub.2 supply unit is started.

In an aspect, the application discloses a method for producing renewable hydrocarbon fuels where the method includes electrolysis of a mixture to produce an electrolysis product comprising a renewable diesel and optionally a renewable gasoline, where the mixture includes (i) free fatty acids from a biorenewable feedstock, and (ii) terminal monomethyl-branched carboxylic acids, and where the renewable diesel includes terminal monomethyl-branched paraffins and terminal monomethyl-branched alkenes.

A system of treating waste materials (28) is provided, and includes a waste treatment reactor (10) configured to treat the waste materials. The waste treatment reactor (10) has a cylindrical body (12) having an inlet (14) to receive the waste materials, a waste chamber (26) to store the waste materials, and an outlet (16) configured to deliver treated waste materials out of the waste chamber. A bundle reactor (38) has the waste treatment reactor and performs a waste treatment for the waste materials stored in the waste chamber. An energy recirculation assembly (40) is connected to the bundle reactor and recirculates thermal energy associated with the bundle reactor during the waste treatment. The energy recirculation assembly (40) has a heating unit (42) to heat a first region of the bundle reactor, and a cooling unit (44) to cool a second region of the bundle reactor.

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.

Production of fuels from low carbon electricity and from carbon dioxide by the use of a solid oxide electrolysis cell (SOEC) and Fischer-Tropsch is shown. Fischer-Tropsch is an exothermic reaction that can be used to produce steam. Steam produced from the Liquid Fuel Production (LFP) reactor system, where the Fischer-Tropsch reaction occurs, is used as feed to the SOEC. The higher temperature steam improves the efficiency of the overall electrolysis system. The integration of the LFP steam improves the efficiency of the electrolysis because the heat of vaporization for the liquid water does not have to be supplied by the electrolyzer.

A method, a system, and an apparatus of certain embodiments are provided to recover water and carbon dioxide from combustion emissions. The recovery includes, among other things, electrolysis and carbon dioxide capture in a suitable solvent. The recovered water and carbon dioxide are subject to reaction, such as a catalytic methanation reaction, to generate at least methane.

A method for recycling CO.sub.2 from CO.sub.2 containing inputs to produce hydrocarbon products includes the steps of (i) capturing CO.sub.2 from at least one CO.sub.2 containing input, at least one of the at least one CO.sub.2 containing input including air; (ii) producing a CO.sub.2 feed stream from the captured CO.sub.2; (iii) reacting the CO.sub.2 feed stream with a H.sub.2 feed stream to produce a methane containing output; and (iv) separating the methane containing output so as to at least provide methane and a first waste output, wherein the first waste output is incinerated or gasified to provide one of the at least one CO.sub.2 containing inputs for step (i).

A method for carbon capture and recycling, the method including the steps of: (i) Capturing CO.sub.2 from at least one CO.sub.2 containing input; (ii) Producing a CO.sub.2 feed stream from the captured CO.sub.2; and (iii) Reacting the CO.sub.2 feed stream with a H.sub.2 feed stream to produce a methane containing output.

Disclosed are antioxidants used in compositions and methods to stabilize synthetic feedstock derived from plastic. Some methods disclosed herein include adding an antioxidant composition to a plastic-derived synthetic feedstock composition. Some methods disclosed herein include heating plastic under substantially oxygen free conditions at a temperature of from about 400° C. to about 800° C. to produce a pyrolysis effluent, distilling the pyrolysis effluent, recovering the synthetic feedstock, and adding a stabilizer to the synthetic feedstock to reduce contamination. The disclosure also provides compositions including a synthetic feedstock derived from plastic and an antioxidant.