Methods and systems for treating volatile organic compounds (VOCs) generated in a hydrocarbon treating process are disclosed. An effluent stream containing the VOCs, as well as carbon dioxide (CO.sub.2) is combined with hot exhaust gas from a turbine and provided to a waste heat recovery unit (WHRU). The WHRU is adapted to contain a catalyst bed containing oxidation catalyst capable of effecting the oxidation of the VOCs. The temperature of the catalyzing reaction can be tailored based on the position of the catalyst bed within the temperature gradient of the WHRU. The methods and systems described herein solve the problem of effecting the removal of VOCs from the effluent. Heating the CO.sub.2-containing effluent in the WHRU also lend buoyancy to the effluent, thereby facilitating its dispersal upon release.

Catalyst regeneration processes that include measures for controlling emissions generated during the regeneration are described. The present invention further relates to catalytic processes for producing various chlorinated aromatic compounds that include provisions for controlling emissions during catalyst regeneration.

A SCR catalyst for removing nitrogen oxides comprises: a carrier prepared from a support in which Ti-PILC is mixed with titania; and a catalyst material on the carrier, wherein the catalyst material contains an active material of a vanadium component and a co-catalyst of a tungsten component. On the basis of the total weight of the catalyst, the support Ti-PILC is contained at 0.01-40 wt %, and the support titania is contained at 50 to 90 wt %. In addition, a method for producing a SCR catalyst for removing nitrogen oxides comprises the steps of: preparing a carrier by using a support in which Ti-PILC is mixed with titania; and supporting a catalyst material on the carrier. The present disclosure provides: a SCR catalyst for removing nitrogen oxides, which has an excellent nitrogen oxide removing performance and a high producing convenience; and a method for producing the same.

The present invention relates to a catalyst comprising at least one oxide of vanadium, at least one oxide of tungsten, at least one oxide of cerium, at least one oxide of titanium and at least one oxide of antimony, and an exhaust system containing said oxides.

A process for the removal of nitrous oxide (N.sub.2O) contained in a process off-gas in an axial flow reactor. The process includes the steps of (a) adding an amount of reducing agent into the process off-gas; (b) in a first stage passing in axial flow direction the process off-gas admixed with the reducing agent through a first monolithic shaped catalyst active in decomposing nitrous oxide by reaction with the reducing agent to provide a gas with a reduced amount of nitrous oxide and residual amounts of reducing agent; and (c) in a second stage passing the gas with a reduced amount of nitrous oxide and residual amounts of the reducing agent in axial flow direction through a second monolithic shaped catalyst active in oxidation of the residual amounts of the reducing agent.

Disclosed is a process system and a process for converting the sulfur-containing flue gas into the sulfuric acid. The process system comprises: a flue gas preheater, which for preheating the sulfur-containing flue gas to 15˜30° C. above its dew point, and the flue gas preheater has a glass tube as a heat exchange tube; a flue gas fan for boosting the pressure of the preheated acid process gas and transporting one part of which to a combustion furnace, and the other part of which to a process gas steam heater; a sulfuric acid steam condenser for condensing SO.sub.3 generated by the combined reactor into sulfuric acid. The device of the present invention can resist the fluctuation of SO.sub.2 concentration in the feed gas, and can realize considerable economic benefits and rational utilization of energy.

A sorbent composition that is useful for injection into a flue gas stream of a coal burning furnace to efficiently remove mercury from the flue gas stream. The sorbent composition may include a sorbent with an associated ancillary catalyst component that is a catalytic metal, a precursor to a catalytic metal, a catalytic metal compound or a precursor to a catalytic metal compound. Alternatively, a catalytic metal or metal compound, or their precursors, may be admixed with the coal feedstock prior to or during combustion in the furnace, or may be independently injected into a flue gas stream. A catalytic promoter may also be used to enhance the performance of the catalytic metal or metal compound.

The present invention refers to a method for the preparation of a shell type catalyst for mercury oxidation, the catalyst and the use of the catalyst. The catalyst is prepared by a method comprising mixing titanium dioxide, a compound of a promoter selected from molybdenum and tungsten, and a binder, to prepare a paste; shaping the paste, to obtain a shaped paste; drying and optionally calcining the shaped paste, to obtain a support material; impregnating the support material with an aqueous alkaline impregnation solution comprising a vanadium compound; drying and calcining the impregnated support material, to obtain the catalyst. The catalyst is useful for purifying exhaust gases from coal plants and other power plants where mercury emissions occurs.

A sorbent composition that is useful for injection into a flue gas stream of a coal burning furnace to efficiently remove mercury from the flue gas stream. The sorbent composition may include a sorbent with an associated ancillary catalyst component that is a catalytic metal, a precursor to a catalytic metal, a catalytic metal compound or a precursor to a catalytic metal compound. Alternatively, a catalytic metal or metal compound, or their precursors, may be admixed with the coal feedstock prior to or during combustion in the furnace, or may be independently injected into a flue gas stream. A catalytic promoter may also be used to enhance the performance of the catalytic metal or metal compound.

The present disclosure generally provides catalysts, catalyst articles and catalyst systems including such catalyst articles. In particular, the catalyst composition includes a metal ion-exchanged molecular sieve ion-exchanged with at least one additional metal, which reduces the number of metal centers often present in metal promoted zeolite catalysts. Methods of making and using the catalyst composition are also provided, as well as emission treatment systems including a catalyst article coated with the catalyst composition. The catalyst article present in such emission treatment systems is useful to catalyze the reduction of nitrogen oxides in gas exhaust in the presence of a reductant while minimizing the amount of dinitrogen oxide emission.