Abstract: A method and apparatus for uniting workpieces of silicon-infiltrated silicon carbide with large dimensions includes surrounding each of two silicon-infiltrated silicon carbide workpieces with at least one tightly closing shell in the vicinity of a junction between the workpieces, defining at least one intermediate space between the shell and the workpieces. A vacuum or an inert gas atmosphere is maintained in the intermediate space or spaces. Solder is placed at the junction and the junction is locally heated to soldering temperature for materially bonding the workpieces by soldering at the junction.

Abstract: Apparatus and method for reducing nitrogen oxides in flue gas within a flue gas duct includes a number of distributor tubes for the injection of a reducing agent into the flue gas within the duct. Each distributor tube includes a control valve to be able to set an appropriate injection of the reducing agent to respond to different concentrations of the nitrogen oxides within the flue gas over the cross section of the flue gas duct. Each distributor tube comprises at least two parallel distributor tube segments which extend from opposite sides of the flue gas duct to the center of the flue gas duct. The two parallel distribution tube segments include a plurality of openings along the lengths thereof to supply the reducing agent generally evenly throughout their aligned portions of the cross section.

Abstract: This invention relates to a process for the manufacture of catalysts for the reduction of oxides of nitrogen from exhaust gases and in chemical air cleaning processes in which a catalytically active material containing iron ores, chromium ores and/or zeolite is placed in contact with a carrier means having a series of openings; e.g., wire mesh, expanded or perforated metal or any type of grid-like structure to form a catalytic member. The carrier means is etched with an acid etchant before forming the catalytic member or, instead, the catalytic member is etched with an acid etchant. The catalytic member is bonded by a thermal treatment; e.g., drying, tempering and/or fixing. This invention also relates to catalytic members or products produced by the process. This invention proposes the use of pressure bonding to obtain a catalytic member product which has significantly improved catalytic activity, greater mechanical strength and higher resistance to chipping.

Abstract: A process for the manufacture of catalysts for the reduction of nitrogen oxides in exhaust gases or for chemical air cleaning processes, in which catalyst moldings are produced from a mixture of solid primary materials which include iron oxide or mixtures of iron oxide and chromium oxide and/or manganese oxide, which are reduced to grain sizes less than 2 mm, with the use of inorganic binders and sulfuric acid, and with the possible addition of activating additives, wherein:(a) either the mixture of the solid primary materials is reacted with sulfuric acid, a mixture of sulfuric acid and phosphoric acid or mixtures of sulfuric acid and phosphoric acid containing sulfate, hydrogen sulfate, phosphate or hydrogen phosphate of ammonium, aluminum, iron, vanadium, manganese, molybdenum, chromium, copper and/or cobalt, and moldings are formed from this mixture, or the mixture of the solid primary materials is formed into moldings after the addition of fluid and/or phosphoric acid and/or phosphates, and these molding

Abstract: This invention relates to a process for the manufacture of catalysts for the reduction of nitrogen oxides in exhaust gases or for chemical air cleaning processes, in which catalyst moldings are produced from iron oxide or mixtures of iron oxide and chromium oxide and/or manganese oxide, which are reduced to grain sizes less than 2 mm, with the use of inorganic binders and sulfuric acid, and with the possible addition of activating additives.

Abstract: The invention relates to the use of manganese nodules or deep-sea ores containing manganese of more recent or older crustal layers as catalysts or for the manufacture of catalysts for the reduction of NO.sub.x components in exhaust gases or for the oxidation of NO.sub.x components and SO.sub.2 particles in exhaust gases.With the use of such catalysts, it becomes possible to reduce the NO.sub.x components in exhaust gases by using reduction agents such as NH.sub.3 at relatively low temperatures, for example, 250.degree. C. It is also possible to perform an oxidation reaction first in exhaust gases with the use of such catalysts, for example, with excess oxygen from NO to NO.sub.2.

Abstract: In a process for cleaning a waste gas containing various pollutants, the exhaust gas with the pollutants is introduced directly into a reduction reactor. In the reactor, the pollutants are reduced by ammonia. The catalyst used is iron oxide material or a mixed oxide material of iron oxide and chromium oxide, or a mixture of the mixture material of the mixed oxide material and the iron oxide material.

Abstract: The invention relates to a process for the production of catalysts for the reduction of nitrogen oxides from exhaust gases and similar chemical air cleaning processes, in which a catalytically active material is deposited and bonded on a carrier made of metal, preferably stainless steel. The carrier is preferably in the form of a perforated metal plate, or of rib mesh, or a grid, preferably fabric, honeycombed or knitted material made of metal wire, or a similar material with a high specific surface. To simplify manufacturing and to improve the characteristics of the catalysts, the invention proposes the use of an acid which etches the surface of the metal carrier as the binder for the catalytically active material.

Abstract: The invention relates to a catalyst in the form of a plate for nitrogen oxide reduction in exhaust gases manufactured by molding granular Cr.sub.2 O.sub.3 or a mixture of granular Fe.sub.2 O.sub.3 with Cr.sub.2 O.sub.3 with phosphoric acid or sulphuric acid as binder, characterized by the fact that a combination is molded of separately prepared mixtures of Cr.sub.2 O.sub.3 or (Fe.sub.2 O.sub.3 +Cr.sub.2 O.sub.3) with phosphoric acid as binder, and of Cr.sub.2 O.sub.3 or (Fe.sub.2 O.sub.3 +Cr.sub.2 O.sub.3) with sulphuric acid as binder.

Abstract: A mounting frame for a block-type parallel mounting of catalyst plates is provided. The block mounting has frame members separated by a distance substantially corresponding to the width of the catalyst plates to be mounted. The frame members are provided with a series of guide slots open on top for admission of the catalyst plates. On the bottom edges of the frame members, there are provided base supports for the bottom edges of the catalyst plates. The frame members themselves also form lateral supports for the catalyst plates to prevent movement thereof when mounted in the module. The mounting modules, once loaded with the planar elements, can be combined into a larger frame in a horizontal mode, or they can be vertically stacked, such as in the flue of a combustion furnace itself. The plates are typically pre-coated with a material that is catalytic to further the conversion of the gaseous compounds passing thereby.

Abstract: A quadrangular catalyst block having a plurality of through-going slots separated by intermediate walls, each of the slots having first and second characterizing dimensions, with one of the characterizing dimensions being significantly greater than the other.

Abstract: The invention relates to a cartridge to hold catalyst plates, which plates are spaced apart, thereby leaving open slot-shaped channels for the passage of fluids to be cleaned catalytically by the plates. The cartridge is shaped in a parallelepiped or an essentially cubic form. There are recesses which form mountings for the insertion of the catalyst plates on at least two sides facing one another. The recesses are groove-like, into which the edges of the catalyst plates fit. For the simplest possible and most solid fastening of the catalyst plates in the cartridge, the mountings comprise a metal wire mesh as the static element, which is coated with a coating containing vermiculite or a similar material which expands when heated. Zeolite may also be used as the coating material.

Abstract: A process for the manufacture of catalyst moldings from granular catalyst material, preferably iron ore, chromium ore or a similar ore, with the use of a binder is disclosed. The granular catalyst material is thermally pre-treated in a temperature range of approximately 250.degree. to 1000.degree. C., before it is mixed with dilute and/or concentrated sulfuric acid functioning as the binder.

Abstract: The invention relates to a process for the manufacture of a catalyst for the reduction of nitrogen oxides in exhaust gases. The catalyst contains a metal oxide. The catalyst is preferably used for catalytic reduction with ammonia. The process comprises screening a natural goethite iron ore to the required grain size and then treating the ore with sulfuric acid. Subsequently, the goethite iron ore is heated to a temperature which approximately equals the temperature at which it will be used in the catalytic reaction.

Abstract: In a process for the manufacture of catalyst moldings a natural raw material containing Fe.sub.2 O.sub.3, Cr.sub.2 O.sub.3 or another such catalyst component such as TiO.sub.2, NbO.sub.2, WO.sub.3, V.sub.2 O.sub.5 or MoO.sub.3 is screened to a grain size equal to or less than approximately 0.25 mm. This screened base mixture is thoroughly blended, and then preferably a concentrated sulphuric acid is added. This mixture of material is then pressed into a molding in a hydraulic press with a pressure of approximately 500 bar to produce the molding.

Abstract: The invention relates to catalyst plates for reducing nitrogen oxide in exhaust gases. These plates are molded of granular Fe.sub.2 O.sub.3 catalyst material and a binder. To achieve high activity and strength in the plates, these are molded of a combination of a first mixture comprised of Fe.sub.2 O.sub.3 catalyst material and phosphoric acid as binder, and a second, separately-produced mixture comprised of Fe.sub.2 O.sub.3 catalyst material and sulphuric acid as binder. The plates can also be a molding having layers, which layers have alternate layers of the first and second mixtures.

Abstract: A structure made from catalyst for use in the separation of nitrogen oxides from combustion exhaust gases which contain dust. The catalytic structure has plates with spaces therebetween to carry a flow of the exhaust gas therethrough. The catalyst is constructed of individual ceramic plates. The abrasion or wear resistance of the plates is chosen such that the dust in the exhaust gases flowing through the spaces abrades the plate surface at a rate which is at least equivalent to the deactivation of the catalyst surface by action of the nitrogen oxides, which constantly provides a fresh catalyst surface for reaction with the nitrogen oxides. The movement of the exhaust gas through the catalytic structure carries the dust and abraded material along with it and out of the structure.

Abstract: A process for the removal of nitrogen oxides and soot from exhaust gases from machines and combustion installations burning heavy fuel oil by means of free-passage catalysts at increased temperatures with the addition of ammonia into the exhaust gas stream ahead of the catalysts. To make the process mre effective, the soot adhering to the catalyst surfaces is removed by burning it off and/or by friction resulting from the admixture of sand, ash or similar abrasive mixtures into the exhaust gas stream ahead of the catalysts.

Abstract: A catalyst for use with ammonia for the selective reduction of nitrogen oxides in waste gases. The catalyst comprises a mixture of substances which has high activity and selectivity with regard to nitrogen oxide conversion and high sorption capabilities with regard to ammonia, but low oxidation capabilities with regard to sulfur dioxide, ammonia, or similar substances. The invention also provides a process for the manufacture and use of such catalysts.

Abstract: This invention relates to mounting porous ceramic material to metal surfaces. The metal surfaces may either be flat surfaces or tubes. The ceramic material is held onto a perforated metal sheet by screwed-in spiral springs. The perforated metal sheet acts as a holding device and is located adjacent to a metal surface. The invention provides for porous ceramic insulation which is conveniently mounted with relation to the metal surface. Spiral springs absorb the stresses which occur during use.