A method for removing amine contaminants from both liquid and gaseous hydrocarbon streams and methods thereof are described. An additive that reacts with said contaminant to form water-soluble compounds is injected into the hydrocarbon streams.

A system for removing mercaptan contaminants from both liquid and gaseous hydrocarbon streams and methods thereof are described. An additive that reacts with said contaminant to form water-soluble compounds is injected into the hydrocarbon streams.

A method of treating the atmosphere of a storage of vegetable products with a volume greater than 200 m.sup.3, wherein the method comprises at least one step of contacting the atmosphere with a liquid flow by circulation in a packing. A treatment unit of the atmosphere of a storage of vegetable products having a volume greater than 200 m.sup.3, wherein the unit comprises a contacting device comprising a packing, a device for injecting a liquid flow into the contacting device, a device for circulating the storage atmosphere in the contacting device, wherein the contacting device is so designed that the atmosphere is brought into contact with the liquid flow by circulation in the packing.

Methods, apparatus, and compositions for cleaning gas. The use of segmented multistage ammonia-based liquid spray with different oxidation potentials to remove sulfur compounds from gas. The use of different oxidation potentials may reduce unwanted ammonia slip.

Methods of producing a treated gas by removing nitrogenous compounds are disclosed. Methods of recovering ammonia from a gas stream having nitrogenous compounds are disclosed. Methods of producing a fertilizer product from organic waste are disclosed. The methods may include introducing aqueous sulfurous acid into a gas stream having nitrogenous compounds to absorb the nitrogenous compounds in a liquid and produce a treated gas. The methods may also include maintaining the pH of certain solutions above 5 or introducing an oxidant into certain solutions to produce sulfate ions. Systems for removing nitrogenous compounds including a reaction subsystem, a solids-liquid separator, a temperature control subsystem, an oxidation control subsystem, and a recirculation line are also disclosed. The systems may be employed to remove nitrogenous compounds from a gas stream, recover the ammonia from the gas stream, or produce a fertilizer product from the recovered ammonia.

A system for removing contaminants from both liquid and gaseous hydrocarbon streams and methods thereof are described. An additive that reacts with said contaminant to form water-soluble compounds is injected into the hydrocarbon streams.

A process and an apparatus for gas denitration, involving first the use of an oxidizing agent to oxidize NO in a gas to NO.sub.2, then using a denitration agent to absorb the NO.sub.2 in the gas, thus achieving the purpose of denitration.

Methods, apparatus, and compositions for cleaning gas. The use of segmented multistage ammonia-based liquid spray with different oxidation potentials to remove sulfur compounds from gas. The use of different oxidation potentials may reduce unwanted ammonia slip.

Methods, apparatus, and compositions for cleaning gas. The use of segmented multistage ammonia-based liquid spray with different oxidation potentials to remove sulfur compounds from gas. The use of different oxidation potentials may reduce unwanted ammonia slip.

One aspect of the invention relates to a method comprising a single-stage conversion of an atmospheric pollutant, such as NO, NO.sub.2 and/or SO.sub.x in a first stream to one or more mineral acids and/or salts thereof by reacting with nonionic gas phase chlorine dioxide (ClO.sub.2.sup.0), wherein the reaction is carried out in the gas phase. Another aspect of the invention relates to a method comprising first adjusting the atmospheric pollutant concentrations in a first stream to a molar ratio of about 1:1, and then reacting with an aqueous metal hydroxide solution (MOH). Another aspect of the invention relates to an apparatus that can be used to carry out the methods disclosed herein. The methods disclosed herein are unexpectedly efficient and cost effective, and can be applied to a stream comprising high concentration and large volume of atmospheric pollutants.