Process and apparatus (10) are disclosed for capturing and converting an ozone-depleting alkyl halide fumigant from a fumigant/air mixed stream (14) by absorbing it into a metal hydroxide-alcohol buffer solution (26) in an absorber/scrubber (12) to produce a fumigant-free air stream (28). The captured alkyl halide in aqueous alcohol solution can actively react with the metal hydroxide in alcohol solution to produce a value-added product, such as a precipitate metal halide, and another alcohol that further enhances absorption. The absorbing solution is well-mixed with make-up alcohol and alkali streams to maintain the concentration of the metal hydroxide in the desired buffer solution range. The solid precipitate metal halide (52) is separated from the liquid stream, and the metal hydroxide-containing mixed alcohol stream (26) is recycled to the absorber/scrubber (12).

An organic iodine remover is a remover for removing organic iodine and is a substance composed of a cation and an anion, and the cation (for example, a phosphonium cation, an ammonium cation, or a sulfonium cation) has a molecular structure in which an electron donating group (for example, a phosphino group, an amino group, a sulfanyl group, a hydroxy group, or an alkoxy group) is bonded to a phosphorus atom, a nitrogen atom or a sulfur atom. An organic iodine removing apparatus includes: a vessel into which the organic iodine remover for removing the organic iodine is charged; and introduction pipes through which a fluid containing organic iodine is introduced into the organic iodine remover.

The invention relates to a process for producing ethylene glycol and/or ethylene carbonate, said process comprising contacting at least a portion of a recycle gas stream comprising an alkyl iodide impurity with a guard bed system positioned upstream of an ethylene oxide reactor to produce a treated recycle gas stream, wherein the guard bed system comprises silver on alumina; contacting a feed gas stream comprising ethylene, oxygen and at least a portion of the treated recycle gas stream with an epoxidation catalyst in the ethylene oxide reactor to produce an epoxidation reaction product comprising ethylene oxide; and contacting at least a portion of the epoxidation reaction product comprising ethylene oxide with an aqueous absorbent in the presence of an iodide-containing catalyst in an absorber to produce an aqueous product stream comprising ethylene carbonate and/or ethylene glycol and the recycle gas stream comprising the alkyl iodide impurity.

A system and process for the recovery of at least one halogenated hydrocarbon from a gas stream. The recovery includes adsorption by exposing the gas stream to an adsorbent with a lattice structure having pore diameters with an average pore opening of between about 5 and about 50 angstroms. The adsorbent is then regenerated by exposing the adsorbent to a purge gas under conditions which efficiently desorb the at least one adsorbed halogenated hydrocarbon from the adsorbent. The at least one halogenated hydrocarbon (and impurities or reaction products) can be condensed from the purge gas and subjected to fractional distillation to provide a recovered halogenated hydrocarbon.

A system and process for the recovery of at least one halogenated hydrocarbon from a gas stream. The recovery includes adsorption by exposing the gas stream to an adsorbent with a lattice structure having pore diameters with an average pore opening of between about 5 and about 50 angstroms. The adsorbent is then regenerated by exposing the adsorbent to a purge gas under conditions which efficiently desorb the at least one adsorbed halogenated hydrocarbon from the adsorbent. The at least one halogenated hydrocarbon (and impurities or reaction products) can be condensed from the purge gas and subjected to fractional distillation to provide a recovered halogenated hydrocarbon.

Novel methods for pretreating a rare-gas-containing stream exiting an etch chamber followed by recovering the rare gas from the pre-treated, rare-gas containing stream are disclosed. More particularly, the invention relates to the pretreatment and recovery of a rare gas, such as xenon or krypton, from a nitrogen-based exhaust stream with specific gaseous impurities generated during an etch process that is performed as part of a semiconductor fabrication process.

Disclosed are a flue gas purification and waste heat utilization system and method. The system comprises a flue gas exhaust unit, a primary waste heat utilization unit, a primary flue gas purification unit, a secondary waste heat utilization unit and a secondary flue gas purification unit that are sequentially connected in a flue gas flow direction, wherein the primary flue gas purification unit is configured for removing NO.sub.x, large particles and CO in the flue gas, the secondary flue gas purification unit is configured for removing NO.sub.x and dioxin in the flue gas, an ammonia-spraying device is externally connected between the flue gas exhaust unit and the primary waste heat utilization unit, and the ammonia-spraying device is configured for injecting ammonia gas into the flue gas exhausted from the flue gas exhaust unit.

Disclosed are a flue gas purification and waste heat utilization system and method. The system comprises a flue gas exhaust unit, a primary waste heat utilization unit, a primary flue gas purification unit, a secondary waste heat utilization unit and a secondary flue gas purification unit that are sequentially connected in a flue gas flow direction, wherein the primary flue gas purification unit is configured for removing NO.sub.x, large particles and CO in the flue gas, the secondary flue gas purification unit is configured for removing NO.sub.x and dioxin in the flue gas, an ammonia-spraying device is externally connected between the flue gas exhaust unit and the primary waste heat utilization unit, and the ammonia-spraying device is configured for injecting ammonia gas into the flue gas exhausted from the flue gas exhaust unit.

A process for the purification of CO.sub.2 from chlorinated hydrocarbons and non-chlorinated hydrocarbons, comprising: contacting a CO.sub.2 stream with a chromium oxide catalyst, wherein the stream comprises the CO.sub.2, and impurities, wherein the impurities comprise the non-chlorinated hydrocarbons and the chlorinated hydrocarbons; forming a purified CO.sub.2 stream by interacting the impurities with the chromium oxide catalyst to form additional CO.sub.2 and chromium chloride; and regenerating the chromium oxide catalyst by contacting the chromium chloride with an oxygen containing gas stream.

A process for the purification of CO.sub.2 from chlorinated hydrocarbons and non-chlorinated hydrocarbons, comprising: contacting a CO.sub.2 stream with a chromium oxide catalyst, wherein the stream comprises the CO.sub.2, and impurities, wherein the impurities comprise the non-chlorinated hydrocarbons and the chlorinated hydrocarbons; forming a purified CO.sub.2 stream by interacting the impurities with the chromium oxide catalyst to form additional CO.sub.2 and chromium chloride; and regenerating the chromium oxide catalyst by contacting the chromium chloride with an oxygen containing gas stream.