The present invention relates to catalyst compositions containing a mixed oxide catalyst of formula (I) or formula (II) as described herein, their preparation, and their use in a process for ammoxidation of various organic compounds to their corresponding nitriles and to the selective catalytic oxidation of excess NH.sub.3 present in effluent gas streams to N.sub.2 and/or NO.sub.x.

Apparatus and methods for oxidizing an ammonia desulfurization solution. The apparatus may include an oxidation air system. The apparatus may include an oxidation tank. The apparatus may include in the tank, a gas-liquid dispersion enhancer. The enhancer may include a sieve plate layer that includes a sieve plate. The sieve plate layer may be one of a plurality of sieve plate layers. The plurality may include two or three sieve plate layers. The apparatus may include an oxidation enhancing device mated to the tank. The oxidation enhancing device may include an acoustic wave generating device. The oxidation enhancing device includes an ultrasonic wave generating device. The ultrasonic generating device may be configured to provide a sound intensity in the range 12 to 40 Watts/Liter. The ultrasonic generating device may be configured to provide to a liquid sound intensity in the range 12 to 40 Watts/Liter.

In a helium purification process, a stream containing at least 10% of helium, at least 10% of nitrogen in addition to hydrogen and methane is separated to form a helium-enriched stream containing hydrogen, a first stream enriched in nitrogen and in methane and a second stream enriched in nitrogen and in methane, the helium-enriched stream is treated to produce a helium-rich product and a residual gas containing water, the residual gas is treated by adsorption (TSA) to remove the water and the regeneration gas from the adsorption is sent to a combustion unit (O).

Disclosed is a catalyst suitable for the catalytic oxidative cracking of a H.sub.2S-containing gas stream. The catalyst comprises at least one or more active metals selected from the group consisting of iron, cobalt, and nickel, supported by a carrier comprising ceria and alumina. The active metal is preferably in the form of its sulphide. Also disclosed is a method for the production of hydrogen from a H.sub.2S-containing gas stream, comprising subjecting the gas stream to catalytic oxidative cracking so as to form H.sub.2 and S.sub.2, using a catalyst in accordance with any one of the composition claims.

The invention provides a device and system for decomposing and oxidizing of gaseous pollutants. A novel reaction portion reduces particle formation in fluids during treatment, thereby improving the defect of particle accumulation in a reaction portion. Also, the system includes the device, wherein a modular design enables the system to have the advantage of easy repair and maintenance.

The present invention solves the existing problem of using very expensive oxidation reagents, such as H.sub.2O.sub.2 and ozone, in removal of NO.sub.x and SO.sub.x from flue gases, by performing simultaneous oxidation of NO.sub.x and SO.sub.x with atmospheric oxygen in a combined system for catalytic oxidation and wet-scrubbing of both NO.sub.x and SO.sub.x from a flue gas and manufacturing fertilisers. Two major configurations of the oxidation system are disclosed in the present invention. The first configuration operates on oxygen-enriched air to increase efficiency of the oxidation reaction and requires an additional oxygen concentrator unit. The second configuration operates on atmospheric air at ambient conditions and requires an additional catalyst activation unit. In the second configuration, the efficient oxidation process is carried out at low temperatures of about 30-90 C. in the presence of recovered and re-activated catalyst. This temperature is a result of the exothermic character of the reaction, and therefore, no heating is required in the process.

A dynamically adjustable rate sulfur recovery process continuously calculates and adjusts sour gas stream operating pressure and/or flow rate to maximize sweet gas output, thereby improving efficiency. A corresponding desulfurization system may include a fixed-sized pressure vessel, a flow control valve that controls the rate of flow of a sour gas stream into the pressure vessel, a sensor that measures sulfur concentration in the sour gas stream, a reagent tank, an oxidizer tank, and a phase separator that separates sweet gas as a gaseous phase after hydrogen sulfide in the sour gas stream in the pressure vessel is converted to elemental sulfur, sulfur species, or both by contact with reagent from the reagent tank and oxidizer from the oxidizer tank. A PLC (programmable logic controller) continuously calculates updated flow rates based on sulfur concentration measurements from the sensor to achieve maximum sweet gas production.

This disclosure provides a method for treating natural gas comprising causing at least some of a sour natural gas stream comprising hydrocarbon gas and hydrogen sulfide to contact an amine or pass through a separation system. A sweet natural gas stream comprising hydrocarbon gas and a waste gas stream comprising hydrogen sulfide are formed by contacting the sour natural gas with an amine or by passing it though a separation device. At least some of the hydrogen sulfide in the waste gas stream is oxidized, forming an exhaust gas stream comprising sulfur dioxide, which is then contacted with water or reactant and water solution or slurry to destroy or convert SO.sub.2 into a less environmentally harmful compound.

Methods of producing a treated gas by removing nitrogenous compounds are disclosed. Methods of recovering nitrogenous compounds from a gas stream are disclosed. Methods of producing a fertilizer product from organic waste are disclosed. The methods may include introducing a gas stream having nitrogenous compounds into a nitrogenous liquid containing a salt of ammonia to absorb the nitrogenous compounds in the liquid and produce a treated gas. The methods may also include controlling the pH of certain solutions or introducing an oxidant into certain solutions to produce nitrogen ions. Systems for removing nitrogenous compounds including a reaction subsystem, an oxidation control subsystem, a dissolved solids concentrator, and a recirculation line are also disclosed. The systems may be employed to remove nitrogenous compounds from a gas stream, recover the nitrogenous compounds from the gas stream, or produce a fertilizer product from the recovered nitrogenous compounds.

A system and method of using the system for controlling oxidation of sulfites to reduce total nitrite and nitrate levels in a slurry is disclosed. The system includes a tank having an inlet for receiving a slurry produced in a wet flue gas desulfurization process. The tank also includes an inlet for receiving a gas. The inlet for receiving the gas is operable to disperse at least a portion of the gas received in the tank through at least a portion of the slurry received in the tank. A sensor is configured to measure a sulfite concentration of the slurry received in the tank to obtain a sulfite concentration measurement. In some embodiments, the sensor is a sulfite analyzer. In other embodiments, the sensor is a virtual analyzer. The system also includes a controller. Software executing on the controller generates an electronic signal affecting an adjustment of a flow rate of gas into the slurry in the tank based at least in part on the sulfite concentration/sulfite concentration measurement.