The invention relates to a method and a device for selective catalytic NOx reduction in waste gases containing oxygen, using ammonia and a reduction catalyst (9). According to the said method, gaseous ammonia is provided by heating a solid storage medium, said storage medium being introduced into a container (1). The inventive method and device are particularly suitable for use in automobiles.

Method and device for selective catalytic nox reduction

A system for storing ammonia in and releasing ammonia from a storage material capable of binding and releasing ammonia reversibly by adsorption or absorption for a process with a gradual ammonia demand that can vary over the time. The system has a container capable of housing the ammonia-containing storage material; a heating source arranged to supply heat for the desorption of ammonia from the solid storage medium; and a controller arranged to control the heating source to release ammonia. The heating source is arranged inside the container and surrounded by ammonia storage material. A controllable dosing valve is arranged to dose released ammonia according to the ammonia demand. The controller comprises a feed-forward control arranged to control the heat supplied by the heating source, based on the ammonia demand.

A system for storing ammonia in and releasing ammonia from a storage material and method for storing and releasing ammonia

A system for NO x reduction in combustion gases, especially from diesel engines, incorporates an oxidation catalyst to convert at least a portion of NO to NO 2 , a particulate filter, a source of reductant such as NH 3 and an SCR catalyst. Considerable improvements in NO x conversion are observed.

CATALYTIC REDUCTION OF NOx

A system for abating undesired component(s) from a gas stream containing the same, such as halocompounds, acid gases, silanes, ammonia, etc., by scrubbing of the effluent gas stream with an aqueous scrubbing medium. Halocompounds, such as fluorine, fluorides, perfluorocarbons, and chlorofluorocarbons, may be scrubbed in the presence of a reducing agent, e.g., sodium thiosulfate, ammonium hydroxide, or potassium iodide. In one embodiment, the scrubbing system includes a first acid gas scrubbing unit operated in cocurrent gas/liquid flow (110), and a second 'polishing' unit operated in countercurrent gas/liquid flow (120), to achieve high removal efficiency with low consumption of water. The scrubbing system may utilize removable insert beds of packing material, packaged in a foraminous containment structure. The abatement system of the invention has particular utility in the treatment of semiconductor manufacturing process effluents.

Apparatus and method for point-of-use treatment of effluent gas streams

A process for producing acetic acid comprising reacting ethylene and oxygen in the presence of a catalyst comprising metallic Pd and at least one member selected from the group consisting of heteropoly-acids and their salts, or in the presence of a catalyst comprising metallic Pd, at least one member selected from the group consisting of heteropoly-acids and their salts and at least one member selected from the group consisting of metallic elements of Groups 11, 14, 15 and 16 of the Long-Form Periodic Table.

Process for producing acetic acid

PURPOSE: To supply a solid reducing agent easily and eliminate troubles of choking a pipeline to supply the solid reducing agent to a denitrifying apparatus by installing a cartridge in which a solid reducing agent is previously packed in a gasifying vessel and gasifying and supplying the reducing agent. CONSTITUTION: A denitrifying catalyst is put in a flue of a nitrogen oxide- containing waste gas and a reducing agent is supplied to the denitrifying catalyst to remove the nitrogen oxides containing in the waste gas by contact-reduction reaction. At that time, a reducing agent cartridge in which a solid reducing agent 15 (e.g. urea) is packed is so set as to be freely detachable and a gasifying vessel 1 having a heating means 6 and an outlet 4 to lead out a vapor of the reducing agent is installed and the outlet 4 is connected to said flue of the waste gas. As a result, the solid reducing agent is supplied easily and troubles of choking a pipeline to supply the solid reducing agent to a denitrifying apparatus is eliminated and dispersion and mixing of the reducing agent to a combustion gas can be carried out excellently. COPYRIGHT: (C)1990,JPO&Japio

Denitrifying apparatus for waste gas using solid reducing agent

A process for continuously and automatically producing a high concentration coal-water slurry having a uniform quality is provided, which process comprises always monitoring the viscosity, concentration, pH, particle diameter distribution and the like of the slurry, detecting the variations of the foregoing and adjusting the quantity of coal fed, the quantity of water fed and the quantities of a surfactant and a pH adjustor added to thereby control the specifications of the coal-water slurry to definite ones.

Process for producing a high concentration coal-water slurry

An improved process for desulfurizing combustion exhaust gases of mainly coal containing sulfur oxides, HF and dust containing Al is provided, which process consists of four steps; a first step of contacting the gases with calcium carbonate or hydroxide in the form of slurry to convert the sulfur oxides into CaSO 3 ; a second step of contacting O 2 with the resulting slurry to convert CaSO 3 into CaSO 4 ; a third step of separating CaSO 4 and mother liquor from the resulting slurry; and a fourth step of preparing a slurry of calcium carbonate or hydroxide to be employed in the first step, from the mother liquor, the pHs of the slurry and the mother liquor in the first and fourth steps being adjusted to 5 or higher by adding alkali such as sodium carbonate. According to the present process, it is possible to prevent hindrance of HF and Al contained in dust to the reaction of SO 2 -absorbent (CaCO 3 or Ca[OH] 2 ) with SO 2 gas, and thereby improve percentage desulfurization and also obtain a high quality gypsum.

Process for desulfurizing combustion exhaust gases

PURPOSE: To simultaneously and economically remove the SOx and NOx in exhaust gases with high efficiency by bringing the exhaust gases and metal sult compd. into contact with a carrier consisting of a gypsum-contg. material. CONSTITUTION: An SiO 2 compd. and/or Al 2 O 3 compd. as well as lime and gypsum are used as raw materials and water is added to this mixture. After the mixture is kneaded, the mixture is subjected to curing and drying treatments under heating to form a desulfurizing agent. CaSO 4 is formed from the limestone contained in this desulfurizing agent and the used desulfurizing agent is used if the desulfurizing agent is brought into contact with the gases contg. the NOx together with the SOx. Further, active components, such as iron, vanadium and copper, are deposited thereon to form a denitrifying catalyst. The carrier increases the gypsum content gradually to increase the acidity when this catalyst is brought into contact with the gases contg. the SOx and NOx. The activity as the denitrifying catalyst is then enhanced and the gases are denitrified with high efficiency. The desulfurization and denitrification are simultaneously executed in this way and the treatment is systematized. COPYRIGHT: (C)1992,JPO&Japio

Catalyst for denitrifying exhaust gas and exhaust gas treating device

CO is recovered from a CO-containing gas by contacting a CO-containing gas with a non-aqueous CO-absorbing solution comprising 3 to 6 moles/l of hexametaphosphateamine, 1 to 4 moles/l of cuprous chloride, 0.1 to 1% by weight of water and an organic solvent, thereby absorbing CO into the CO-absorbing solution from the CO-containing gas, and then atomizing the CO-absorbed solution, thereby stripping CO from the CO-absorbed solution and obtaining a CO gas, while recycling the CO-freed absorbing solution to the absorption of CO from the CO-containing gas with remarkable reduction in the corrosion rate on apparatus materials without impairing the CO absorption, and use of a two-fluid, simultaneous atomizing means for atomizing the CO-absorbed solution together with the vapor of the organic solvent can improve the CO stripping rate, and reduce the CO recovery cost.

Yasuyuki Nishimura

Papers

Denitrifying apparatus for waste gas using solid reducing agent

Process for producing a high concentration coal-water slurry

Process for desulfurizing combustion exhaust gases

Catalyst for denitrifying exhaust gas and exhaust gas treating device

Process for absorbing CO