Abstract: Integrated process for the synthesis of ammonia and nitric acid, comprising a synthesis of nitric acid including the following steps: a) subjecting a stream of ammonia (10) to catalytic oxidation, obtaining a gaseous stream containing nitrogen oxides (13); b) subjecting said gaseous stream to a process of absorption of nitrogen oxides, providing nitric acid (16) and a tail gas (17) containing nitrogen and residual nitrogen oxides; c) subjecting at least a portion of said first tail gas (17) to a process of removal of nitrogen oxides, providing a nitrogen oxides-depleted tail gas (18), and comprising a synthesis of ammonia by catalytic conversion of a make-up gas (126, 226) comprising hydrogen and nitrogen in an ammonia synthesis loop, wherein at least a portion (18b, 18d, 21) of said second tail gas is used as nitrogen source for obtaining said make-up gas (126, 226).

Abstract: A method of reducing NOx in tail gas obtained during startup of a plant for preparing nitric acid may involve heating the tail gas from a starting temperature T0, through a threshold temperature TG, to an operating temperature TB at which steady-state operation of the plant can occur (T0<TG<TB). NOx-containing tail gas may be passed through a storage medium and at least partially stored while the temperature of the tail gas is lower than the threshold temperature TG. The NOx may be released, preferably when the temperature of the tail gas has attained the threshold temperature TG. The NOx may be combined with a reducing agent in the presence of an SCR catalyst after the temperature of the tail gas has exceeded the threshold temperature TG, but not before, resulting in catalytic reduction of at least a portion of the NOx.

Abstract: The present invention relates to a reactor R with apparatus D, the latter comprising a gas- and/or liquid-permeable tray B, in the edge region of which there is disposed a lateral boundary W which fully encloses the tray B and forms a volume V comprising catalytic and/or noncatalytic shaped bodies (F), wherein there is at least one braid made of precious metal and/or base metal on the upstream side opposite the tray B, and the catalytic and/or noncatalytic shaped bodies (F) are selected from (i) shaped bodies (F1) in the form of straight prisms, the footprint of which is selected from triangle, rectangle, hexagon or fragments of these polygons, and (ii) a combination of the shaped bodies (F1) with shaped bodies (F2) that are smaller than the shaped bodies (F1), wherein groups of m to n shaped bodies (F1), m and n being an integer from 3 to 30 with n>m, are framed in a metal cassette open in the upstream direction and closed in the downstream direction by a gas-permeable tray, in a virtually seamless manner

Abstract: An ammonia oxidation catalyst basket design has two support grids. A first grid supports the primary catalyst and a separate, second grid supports the secondary catalyst. This dual grid design separates the two catalysts, and enables the catalysts to be independent of each other. Any interruption in the primary or the secondary catalyst does not impede or adversely impact on the structure or function of the other catalyst.

Abstract: A selective catalytic reduction catalyst composition for converting oxides of nitrogen (NOx) in an exhaust gas using a nitrogenous reductant comprises a mixture of a first component and a second component, wherein the first component is an admixture of the H-form of an aluminosilicate mordenite zeolite (MOR) and an iron-promoted aluminosilicate MFI zeolite; and the second component is a vanadium oxide supported on a metal oxide support, which is titania, silica-stabilized titania or a mixture of both titania and silica-stabilized titania, wherein the weight ratio of the first component to the second component is 10:90 to 25:75.

Abstract: Provided is a catalyst composition for treating exhaust gas comprising a blend of a first component and second component, wherein the first component is an aluminosilicate or ferrosilicate molecular sieve component wherein the molecular sieve is either in H+ form or is ion exchanged with one or more transition metals, and the second component is a vanadium oxide supported on a metal oxide support selected from alumina, titania, zirconia, cella, silica, and combinations thereof. Also provided are methods, systems, and catalytic articles incorporating or utilizing such catalyst blends.

Abstract: Described herein are fenestrated placental tissue allografts, methods for using the same for treating wounds that produce an exudate and to promote the healing process, and apparatus and kits for making the same that minimize or eliminate cross-contamination with placental tissue from other placental donors.

Abstract: Ammonia oxidation catalyst units comprising a pair of honeycomb-type blocks having interplaced between them a layer of a gas permeable material performing the function of radially mixing the gas flow, said blocks comprising an ammonia oxidation catalysts, and having height of less than 15 cm and the interplaced layer height of 3 to 0.5 cm.

Abstract: An apparatus and a process are described for preparation of nitric acid from ammonia and oxygenous gas by the single pressure or dual pressure process, in which the oxidation of the ammonia used is accomplished by means of compressed process air which has been compressed in at least one compressor over a catalyst, and the nitrous gas formed by the oxidation is at least partly absorbed by water, forming nitric acid, and the unabsorbed residual gas is expanded for the purpose of recovering compressor work in at least one multistage residual gas turbine (1).

Abstract: The invention relates to processes for reducing ammonia loss and odor from organic material or waste to the atmosphere. A plasma generator is applied to upgrade organic waste and manure with a mixture of acidic nitrates and nitrites. The present invention also relates to an acidic nitrate solution, suitable for reducing ammonia loss and odor from organic material or waste to the atmosphere, and a process for producing such an acidic nitrate solution. The invention further comprises plants for reducing ammonia loss and odor from organic material or waste to the atmosphere.

Abstract: An apparatus and a process are described for preparation of nitric acid from ammonia and oxygenous gas by the single pressure or dual pressure process, in which the oxidation of the ammonia used is accomplished by means of compressed process air which has been compressed in at least one compressor over a catalyst, and the nitrous gas formed by the oxidation is at least partly absorbed by water, forming nitric acid, and the unabsorbed residual gas is expanded for the purpose of recovering compressor work in at least one multistage residual gas turbine (1).

Abstract: A process is described for startup and/or shutdown of a plant for preparation of nitric acid from ammonia and oxygenous gas by the single pressure or dual pressure process, in which the ammonia used is oxidized by means of compressed process air over a catalyst, said process air having been compressed in at least one compressor (6), the nitrous gas formed by the combustion is cooled in one or more process gas coolers (3) equipped with pipe coils for a cooling medium and in one or more feed water preheaters (2) equipped with pipe coils for a cooling medium, and the cooled nitrous gas is subsequently absorbed at least partly by water, forming nitric acid, and the unabsorbed residual gas is expanded in at least one residual gas turbine (11) for the purpose of recovering compressor work.

Abstract: The material proposed for sealing off cavities between structural components formed of materials having different thermal characteristics comprises an intumescent mat completely sealed in a polymeric film and the interior bounded by the polymeric film and containing the intumescent mat is evacuated.

Abstract: A process for producing ammonium nitrate is disclosed and in which: a) a gaseous oxidizer feed composed at least substantially of ammonia, steam and an oxidizing gas is exposed to conditions whereby the ammonia is oxidized to produce a reaction mixture including nitrogen monoxide and water vapor, b) the reaction mixture is cooled in a heat exchanger whereby the nitrogen monoxide is oxidized, the water vapor is condensed and the products of the nitrogen monoxide oxidation react with and are absorbed by the condensed water to form a nitric acid stream, with substantially all of the nitrogen monoxide in the reaction mixture being converted to nitric acid, and c) the nitric acid stream is reacted with a stream of ammonia in an ammonium nitrate producing stage to form the ammonium nitrate.

Abstract: The invention relates to a process and apparatus for preparing nitric acid by catalytic oxidation of NH3 by means of oxygen and subsequent reaction of the NOx formed with an absorption medium in an absorption tower, which comprises a catalyst bed for N2O decomposition arranged in the process gas downstream of the catalytic NH3 oxidation and upstream of the absorption tower in the flow direction and a catalyst bed for NOx reduction and effecting a further decrease in the amount of N2O arranged in the tailgas downstream of the absorption tower in the flow direction, wherein the amount of N2O removed in the catalyst bed for N2O removal arranged in the process gas is not more than that which results in an N2O content of >100 ppmv and a molar N2O/NOx ratio of >0.

Abstract: A process for producing nitric acid is disclosed in which a gaseous oxidiser feed composed at least substantially of ammonia, steam and an oxidising gas is exposed to conditions whereby the ammonia is oxidised to produce a reaction mixture including nitrogen monoxide and water vapour. The reaction mixture is then cooled in a heat exchanger whereby: a) the nitrogen monoxide is oxidised and the water vapour is caused to condense, b) the products of the nitrogen monoxide oxidation react with and are absorbed by the condensed water, and c) substantially all of the nitrogen monoxide in the reaction mixture is converted to nitric acid. Also disclosed is a nitric acid solution when produced by the disclosed process.

Abstract: Method and apparatus for carrying out highly exothermic catalyzed reactions, like so-called oxidative reactions, in pseudo-isothermal conditions, for example the reaction for producing nitric acid and the reaction for producing formaldehyde.

Abstract: A method for reducing the levels of nitrogen oxides in the tail gas from a nitric acid production process by adding ozone to the absorber column of the production process. Nitric acid formation is also intensified by adding a mixture of secondary air and oxygen to the absorber column.

Abstract: By a method and a device for preventing corrosion on and in the region of a gas inlet nozzle during nitric acid condensation, contact of the condensing gas with the nozzle and with the surroundings of the nozzle are supposed to be minimized. This is achieved in that the gas inlet nozzle has a sleeve on the inside in the transition region to the interior of the condenser, by which sleeve a gas inlet orifice in the form of an annular gap is formed, whereby the annular space is provided with at least one feed opening for secondary air, so that an enveloping flow of secondary air is produced around the entering NO gas.

Abstract: The present invention relates to a method for manufacturing nitric acid wherein a gaseous mixture, including air and ammonia, is transported on a catalyst including platinum to carry out catalytic oxidation of the ammonia, and is characterized in that a sulfurated component is added to the gaseous mixture.

Abstract: Ammonia in a gas stream comprising oxygen and nitrogen may be effectively completely oxidized to a mixture of NO and NO2 for further processing to nitric acid. The gas stream is flowed over fine particles of La1-xSrxCoO3 and/or La1-xSrxMnO3, and/or La1-xSrxFeO3 where x=about 0.1, 0.2, or 0.3. The particles are supported as catalyst layers on gas stream-contacting surfaces of a flow-through catalyzed oxidation reactor. These relatively inexpensive perovskite-type materials may be used to promote oxidation of ammonia at temperatures below about 450° C. to about 500° C. to selectively produce a mixture of NO and NO2. This mixture is suitable for further oxidation to NO2 for adsorption into water to make nitric acid.

Abstract: By a method and a device for preventing corrosion on and in the region of a gas inlet nozzle during nitric acid condensation, contact of the condensing gas with the nozzle and with the surroundings of the nozzle are supposed to be minimized. This is achieved in that the gas inlet nozzle has a sleeve on the inside in the transition region to the interior of the condenser, by which sleeve a gas inlet orifice in the form of an annular gap is formed, whereby the annular space is provided with at least one feed opening for secondary air, so that an enveloping flow of secondary air is produced around the entering NO gas.

Abstract: A catalyst charge for ammonia oxidation, including the Andrussow process, comprises a first stage ammonia oxidation catalyst capable of oxidizing 20 to 99% of designed ammonia throughput, to produce a first stage product gas comprising unreacted ammonia, oxygen and nitrogen oxides, and a second stage ammonia oxidation catalyst capable of completing the oxidation of unreacted ammonia. Low levels of nitrous oxide are produced an extended campaign lengths may be seen.

Abstract: The present invention relates to a method for manufacturing nitric acid wherein a gaseous mixture, including air and ammonia, is transported on a catalyst including platinum to carry out catalytic oxidation of the ammonia, and is characterized in that a sulfurated component is added to the gaseous mixture.

Abstract: N2O is removed in nitric acid manufacture by using catalysts comprising three-dimensional structures coated with catalytically active materials.

Abstract: The invention relates to a method for the production of nitric acid having a concentration of between 50 and 76%, from ammonia and gas containing oxygen, under pressure, according to a single pressure method or dual pressure method. The expansion of the residual gas takes place in at least two stages in a work efficient manner. At least one device for heating the previously expanded gas to a temperature of more than 450° is disposed between every other expansion stage, using waste heat from the production process of nitric acid.

Abstract: The invention relates to a process for the catalytic decomposition of N2O to N2 and O2. This process is carried out at a high temperature, generally of between 700 and 1000° C., at a high HSV and in the presence of a catalyst composed of a mixed oxide of zirconium and of cerium existing in the form of a solid solution.

Abstract: A process for producing nitric acid of a concentration in the range of 68 to 76% by weight, using the mono-pressure or the dual-pressure process in which the ammonia feedstock is combusted with the aid of compressed process air. The water vapour content of the process air used for combustion and/or stripping and imported from outside the system, is reduced in this process.

Abstract: A combination comprising a bed of a particulate copper-containing catalyst bed, a guard bed in the form of shaped units formed from lead carbonate and/or basic lead carbonate particles having an average (by volume) particle size below 100 ?m.

Abstract: Ammonia oxidation by passing a mixture of air and ammonia over a catalyst containing at least one cobalt compound at an elevated temperature wherein, prior to contact with the catalyst, the air is passed through an absorber comprising a support carrying an absorbent material for acidic gases.

Abstract: A reactor for the catalytic oxidation of ammonia to form nitrogen oxides which has a noble metal gauze catalyst and a heat exchanger in that order in the direction of flow, a catalyst for the decomposition of N2O is located between the noble metal gauze catalyst and the heat exchanger and in a process for the catalytic decomposition of N2O in a gas mixture obtained in the preparation of nitric acid by catalytic oxidation of ammonia, where the N2O is decomposed catalytically over a catalyst of the decomposition of N2O, the hot gas mixture obtained from the catalytic oxidation of ammonia is brought to contact with the catalyst for the decomposition of N2O prior to subsequent cooling.

Abstract: A process and a device for reducing the nitrous oxide which is formed during the catalytic combustion of ammonia and oxygen to form nitrogen oxides. A catalyst system including at least one first catalyst mesh element and at least one second catalyst mesh element is used for the catalytic combustion of ammonia and oxygen to form nitrogen oxides, where the minimum of one first catalyst mesh element is a platinum-rhodium mesh and the minimum of one second, downstream catalyst mesh element is a palladium-rhodium mesh with 2-4 wt. % of rhodium.

Abstract: The invention relates to a process for the production of nitric acid of a concentration ranging from 68 to 76% by wt., using the mono-pressure or the dual-pressure process in which the ammonia feedstock is combusted with the aid of compressed process air. The water vapour content of the process air used for combustion and/or stripping and imported from outside the system, is reduced in this process.

Abstract: In the method of preparing nitric oxide by burning NH3 with oxygen, over a catalyst network in which the reaction product gases contain N2O and are cooled, the N2O is eliminated by oxidation or decomposition by immediately passing the reaction product gases over a thermally stable catalyst.

Abstract: The present invention relates to three-dimensional catalyst gauzes for gas reactions knitted in two or more layers from noble metal wires in which the meshes of the individual layers are joined to one another by pile threads. In these catalyst gauzes weft threads are inserted between the mesh layers. These catalyst gauzes have an increased catalytic activity and efficiency in gas reaction. These improvements enable operation with a lower total amount of noble metal employed, for example by reducing the number of gauzes and/or the length of the wire processed in the catalyst gauze and/or the wire thickness, without thereby having to accept disadvantages with respect to the yield and selectivity of the gas reaction, mechanical strength and service life of the gauzes or unavoidable loss of noble metal.

Abstract: A method is provided for performing catalytic or non-catalytic processes which uses oxygen supplied from the permeate side of a mixed oxygen ion and electron conducting membrane by means of a sweep gas at an elevated temperature. The sweep gas is formed by burning fuel in a sweep gas preheater. The sweep gas containing oxygen picked up from the membrane is reacted with a hydrocarbon fuel in a catalytic reactor to form a syngas containing nitrogen and hydrogen. The nitrogen and hydrogen containing syngas is worked up into ammonia; the ammonia is burned in an ammonia burner to produce a nitrogen oxides containing gas, and the nitrogen oxides containing gas is used in the production of nitric acid. The process is able to directly transfer the oxygen containing sweep gas to the catalytic reactor, without any intermediate cooling; recompression and reheating.

Abstract: A process for the production of nitric acid using the dual-pressure process in which the ammonia is burnt at an initial low pressure with the aid of compressed process air and the nitrous gases formed during combustion are at least partly absorbed by water at a second pressure which is higher than the first. This causes nitric acid to be produced and the pressure of the residual gas, which is not absorbed, is reduced to atmospheric pressure in a residual gas expander for the purpose of winning compression potential. Said process provides a solution aimed at optimising the production of nitric acid whilst improving the production parameters and the materials and energy balances. This is achieved by supplying a multishaft geared centrifugal compressor separately with process air and nitrous gas, the process air being compressed to the initial pressure and the nitrous gas being compressed to a second pressure.

Abstract: A process for nondestructive heating and supplying of ammonia feed gas wherein high quality ammonia (typically greater than 90% and as high as 99%) is preserved at temperatures well in excess of the conventional limit of 230° C. (typically from 400 to 700° C.) by controlling the selection of metal surfaces in contact with the hot gas, the bulk temperature of the gas, the wall temperature, the pressure, the contact time, and the spatial surface density. Such hot gases are particularly useful for the manufacture of hydrogen cyanide.

Abstract: Nitrogen oxides are removed from a waste gas stream by contacting the waste gas stream with ammonia, thereby reducing the nitrogen oxides to nitrogen. Residual nitrogen oxides and unreacted ammonia in the waste gas stream leaving the nitrogen oxides reducing step are oxidized to nitrogen pentoxide or nitric acid by contacting this gas stream with ozone. Contact of the ozone and waste gas is preferably carried out in the presence of an aqueous solution at a pH above about 9 and at a temperature above about 75° C., and this step is preferably carried out in the presence of an ammonia-oxidizing catalyst.

Abstract: A process is described for producing nitric acid involving oxidizing ammonia gas to form dinitrogen tetroxide gas, reacting the dinitrogen tetroxide with water in an absorption zone to form aqueous nitric acid and nitric oxide gas, removing a nitric acid/nitric oxide stream from the absorption zone and feeding the stream into a nitric acid bleaching zone, removing impurities from the nitric acid in the bleaching zone to form nitric acid product and adding supplemental oxygen gas to one or more of the reaction streams to increase nitric acid production and or strength. The improvement involves injecting the supplemental oxygen into a nitric acid-containing process stream to form a gas bubble/liquid mixture in the stream, the mixture forming a fine dispersion of gas bubbles having diameters of less than about 0.1 mm.

Abstract: The invention relates to a process for removing nitrogen oxides from a gas stream containing same, which comprises passing the gas stream(A) through a stage for absorbing the nitrogen oxides other than N.sub.2 O in an absorbent or reacting the nitrogen oxides other than N.sub.2 O with an absorbent at a pressure of from 1,5 to 20 bar, and(B) through a stage for reducing the amount of N.sub.2 O, preferably employing the pressure level of step A, and to apparatus therefor and the use thereof.

Abstract: Provided is a process having an increased production capacity for nitric acid, which moves can be operated safely and efficiently. The process comprises forming a reaction mixtures by mixing air, ammonia, oxygen and an inert cooling fluid, preferably water, and then reacting the ammonia with oxygen in a reaction zone to form nitric oxide. The amount of inert cooling fluid in the reaction mixture is sufficient to control the temperature of the mixture and maintain the ammonia percentage below the lower explosion limit for the mixture. The nitric oxide produced in the reaction zone is then oxidized to nitrogen dioxide and its dimer, with additional oxygen being introduced into the process for oxidizing the nitric oxide. The nitrogen dioxide and its dimer is then reacted with water to form the nitric acid.

Abstract: A catalyst composition for oxidation of ammonia in the production of nitric acid incorporates a porous ceramic structure which is at least partially coated, the coating including a layer containing alumina, zirconium and cerium, a layer containing cobalt, cerous zirconium and optionally manganese, and a layer containing platinum.

Abstract: A catalyst assembly is disclosed which comprises a plurality of foraminous wire mesh sheets disposed in intimate nested relation to each other along their broad surfaces, the wire sheets defining a non-planar cross-section which consists of a plurality of undulating corrugations. The border of the catalyst assembly is flattened to allow for secure installation in an ammonia converter. The invention includes individual sheets that are stacked adjacent each other, as well as pads comprising multiplicities of sheets that are edge bonded to each other to form integral units. The catalyst assemblies of the present invention provide a combination of increased surface area and reduced pressure drop that is unique and contributes to improve useful life and corresponding reductions in cost and down time. The catalyst assemblies may be easily manufactured and installed and may be prepared in a variety of sizes and shapes to suit the dimensions and requirements of differing reactors.

Abstract: A process for the preparation and processing of a hydroxylammonium salt solution involves maintaining an aqueous acid reaction medium circulation between a hydroxylammonium salt synthesis zone and an oxime synthesis zone; continuously supplying nitrate ions or nitrogen oxides to be converted into nitrate, by way of nitrogen source for the formation of the hydroxylammonium salt, to the liquid being maintained in circulation; catalytically reducing the nitrate ions with hydrogen to obtain hydroxylamine; removing the ammonium ions, formed as a by-product in the reduction of the nitrate ions, by contacting the circulating liquid with a gas flow consisting of nitrogen oxides generated in catalytic combustion of ammonia. Advantageously, 0.01 to 5 wt. % of the nitrogen oxides formed in the combustion effect reduction of the ammonium ions to nitrogen, and the remainder of the nitrogen oxides are used for the preparation of nitric acid.

Abstract: The present invention relates to processes and apparatus for mixing oxidizable reactants with oxidant and/or oxidizing oxidizable reactants. Through using particular mixing and/or oxidizing arrangements, the risk of flammable or explosive reactions can be significantly reduced or prevented. When ammonia is used as the reactant, nitric acid can be obtained.

Abstract: The present invention provides an improved coextruded medical grade port tubing. The medical grade port tubing provides characteristics that are desirable in the medical industry and therefore can be used as a medical port tubing in, for example, renal therapy or blood donor tubes. To this end, the present invention provides a non-PVC coextruded medical grade port tubing including: an outer layer comprising a blend of polypropylene copolymer and styrene-ethylene-butylene-styrene copolymer; a tie layer; and a core layer including a blend of polyamide and ethylene vinyl acetate.

Abstract: Wires of platinum containing 4 to 12% rhodium or 4 to 12% of palladium and rhodium (4 to 12% being in reference to the sum of palladium and rhodium and not the percent values for each individually) and wires of palladium containing 2 to 15% nickel or 2 to 15% copper or 2 to 15% of nickel and copper (2 to 15% being in reference to the sum of nickel and copper) and having a diameter of 50 to 120 .mu.m, a tensile strength of 900 to 1050 N/mm.sup.2 and an elastic limit of 0.5 to 3% are used for the knitting of round nets for use as catalysts in the oxidation of ammonia and as recovery nets for platinum metals. A flat knitting machine with a gauge of 3.63 to 1.81 mm is also used whereby the loop length is 2 to 6 mm and wherein the loop or width gauge corresponds with the knitting machine gauge so as to provide a loop width of 1.81 to 3.63 mm.

Abstract: The present invention relates to processes and apparatus for mixing oxidizable reactants with oxidant and oxidizing oxidizable reactants. When ammonia is used as the reactant, nitric acid can be obtained. Through using particular mixing and oxidizing arrangements, the volume of reactant oxidized can be significantly increased.

Abstract: Reticulated ceramic or metal substrate coated with Cobalt compounds, noble metals or mixtures thereof are superior catalysts for the oxidation of ammonia to produce nitric oxide.