A process for hydrotreating a feed stream comprising a biorenewable feedstock is disclosed. The process comprises hydrotreating the feed stream in the presence of a hydrotreating hydrogen stream and a hydrotreating catalyst to provide a hydrotreated stream. The hydrotreated stream is separated into a hydrotreated liquid stream and a hydrotreated gas stream. The hydrotreated liquid stream is subjected to stripping to provide a stripper off-gas stream. At least a portion of the stripper off-gas stream is contacted with a caustic stream to provide a sulfur-lean gas stream and a sulfur-rich caustic stream. The sulfur-rich caustic stream is further treated to provide a treated gas stream.

The removal of acid gases (e.g., non-carbon dioxide acid gases) using sorbents that include salts in molten form, and related systems and methods, are generally described.

A process is provided using a concentrated sodium bicarbonate solution as a solubilizer mixed with a calcium hydroxide to chemically produce an insoluble calcium carbonate and produce an alkaline liquid solution, then passing the alkaline liquid solution through detrimental gases in a scrubber to produce an enhanced sodium bicarbonate which regenerates the sodium bicarbonate thus creating a continuous closed loop. The process can also produce a sodium phosphate (trisodium phosphate) by mixing the alkaline liquid solution with a phosphoric acid.

A method for preparing hydrogen sulfide from sulfur dioxide by electrochemical reduction includes electrochemically reducing sulfur dioxide absorbed in an aqueous solution into gaseous hydrogen sulfide with a membrane electrode, resulting in efficient and selective conversion of the sulfur dioxide absorbed in the aqueous solution into the hydrogen sulfide to avoid a deactivation of a cathode due to colloidal sulfur produced on the cathode and adhesion onto a surface of the cathode, wherein the method is carried out at ambient temperature and normal pressure without addition of a reducing agent, having no waste salts produced, and is simple in operation, and is convenient for large-scale application.

A method of exhaust gas scrubbing includes providing recycled concrete fines as a waste material rich in carbonatable Ca and/or Mg phases and with d.sub.90≤1000 μm and a Rosin-Rammler slope n from 0.6 to 1.4 , injecting the waste material into an exhaust gas stream containing CO.sub.2 and/or SO.sub.x for reaction with CO.sub.2 and/or SO.sub.x at a relative humidity of 50 to 100 Vol.-% and a temperature from 40 to 130° C. in an amount of dry waste material ranging from 5 to 30 kg/m.sup.3, withdrawing a partly carbonated and/or sulphurized waste material and purified exhaust gas, and recycling a part of the partly carbonated and sulphurized waste material while the remainder is discharged, as well as use of a waste material slurry for exhaust gas cleaning of CO.sub.2 and/or SO.sub.x.

A method and modular desulfurization-decarbonization apparatus for removing contaminants from exhaust gas is described. The apparatus comprises discrete modular units with distinct functions. The modular units may be housed in standard shipping containers and installed on cargo ships. The modules can be removed and replaced while docking with minimal disruption to ship and port operations.

This invention relates to a system and method for improving sulfur recovery from a Claus unit. More specifically, this invention provides a steam swept membrane tail gas treatment system and method for treating acid gas streams and minimizing sulfur dioxide emissions therefrom.

This invention relates to a system and method for improving sulfur recovery from a Claus unit. More specifically, this invention provides a steam swept membrane tail gas treatment system and method for treating acid gas streams and minimizing sulfur dioxide emissions therefrom.

The present disclose is directed to a method for controlling iodine levels in wet scrubbers, and, in particular, recirculating wet scrubbers by removing the iodine from the scrubbing solution, such as by using ion exchange, absorption, adsorption, precipitation, filtration, solvent extraction, ion pair extraction, and an aqueous two-phase extraction.

The present disclose is directed to a method for controlling iodine levels in wet scrubbers, and, in particular, recirculating wet scrubbers by removing the iodine from the scrubbing solution, such as by using ion exchange, absorption, adsorption, precipitation, filtration, solvent extraction, ion pair extraction, and an aqueous two-phase extraction.