284results about "Nitric acid" patented technology

The invention discloses an electronic-grade nitric acid preparation device and method capable of controlling the filtering speed based on temperature difference, and relates to the technical field of nitric acid preparation.The electronic-grade nitric acid preparation device comprises a first-stage rectifying tower and a second-stage rectifying tower, and a first-stage evaporator and a second-stage evaporator are arranged on the outer sides of the bottoms of the first-stage rectifying tower and the second-stage rectifying tower respectively; compared with an existing filtering part, the temperature control assembly is arranged, the temperature control assembly has double functions, on one hand, liquefied nitric acid entering the filter is preheated, and on the other hand, the filtering speed of the filtering assembly on nitric acid is changed according to needs; in addition, a filling disc is accurately rotated through a reversing motor, so that a target material storage cavity is isolated from the rectifying tower main body, and the risk of negative pressure damage or harmful gas leakage in the tower in the traditional dismounting process is avoided.

The invention relates to a process for removing nitrogen monoxide, nitrogen dioxide and nitrous oxide from an exhaust gas stream obtained in a nitration process, comprising: (a) Removing nitrogen monoxide and nitrogen dioxide from the exhaust gas stream by adding an oxygen comprising gas to the exhaust gas stream, oxidizing the nitrogen monoxide in the gas stream to form nitrogen dioxide, thereby obtaining a gas stream depleted in nitrogen monoxide; (b) Washing the gas stream depleted in nitrogen monoxide with water to obtain a gas stream depleted in nitrogen monoxide and nitrogen dioxide; (c) Converting nitrous oxide in the gas stream depleted in nitrogen monoxide and nitrogen dioxide into nitrogen and carbon dioxide and optionally oxygen in the presence of a nitrous oxide reduction catalyst and in the presence of hydrogen cyanide.

The invention provides a preparation method of an organic polymer photocatalyst and application of the organic polymer photocatalyst in the aspect of photocatalytic synthesis of nitric acid (HNO3) by directly taking nitrogen (N2) and oxygen (O2) as raw materials in water, and additional reagents do not need to be added. It is worthy of notice that the organic polymer photocatalyst (PyOP) shows excellent photocatalytic performance. When O2 is subjected to photocatalytic reduction, the yield of hydrogen peroxide (H2O2) reaches 10147.5 [mu] mol g <-1 > cat, and meanwhile, 672.8 [mu] mol g <-1 > cat of HNO3 can be synthesized by directly utilizing N2 and O2. The preparation method of the photocatalyst provided by the invention is simple, the raw materials are easy to obtain, the preparation cost is low, a metal-free photocatalytic platform only using H2O, N2 and O2 is constructed, and the photocatalyst is used for green and sustainable nitric acid production.

There is provided a method for nitrogen oxide (NOx) synthesis, the method comprising: - providing a gas mixture comprising oxygen and nitrogen in a plasma reactor chamber; and - exciting the gas mixture into plasma in the plasma reactor chamber, wherein a duration of the excitation is in the range ≥0.15 / P nanoseconds & ≤90 / P nanoseconds, wherein P is pressure of the gas mixture in atm, and wherein the gas mixture is provided at a pressure P of ≥ 1.1 atm.

The invention relates to the technical field of nitric acid purification, in particular to purification equipment for producing electronic-grade industrial nitric acid, which comprises a heated barrel, a heating component, a feeding component, a condensing component, a collecting barrel and a gas transmission component, the heating component is connected to the outer wall of the heated barrel, and the condensing component is connected to the bottom of the heated barrel; and the collecting barrel is communicated with the condensing assembly. The heated barrel is divided into the heating area and the feeding area through the arc-shaped pipe, so that acid steam on the inner wall of the arc-shaped pipe exchanges heat with reagent-grade nitric acid in the feeding area, heat released during condensation is absorbed by the reagent-grade nitric acid in the feeding area, and the energy utilization rate is increased; the circulation path in the feeding area and the heating area is only the top of the arc-shaped pipe, so that direct convection between the solution in the heating area and the solution in the feeding area is reduced, loss of heat of the solution in the heating area is reduced, heat is concentrated in the heating area due to the heat insulation effect of the arc-shaped pipe, the heating effect is further improved, and the evaporation speed is increased.

The invention discloses a conjugated polymer photocatalyst, a preparation method thereof and application of the conjugated polymer photocatalyst in photocatalytic synthesis of nitric acid, and belongs to the technical field of polymer materials and photocatalysis. The preparation method of the catalyst mainly comprises the following steps: synthesizing an intermediate 2CzTPN-Br through a nucleophilic substitution reaction, then synthesizing an intermediate TBBA through an esterification reaction, and finally copolymerizing the intermediate 2CzTPN-Br and the intermediate TBBA through a coupling polymerization reaction to obtain the target catalyst. The preparation method disclosed by the invention is controllable in process, and the obtained catalyst does not need to participate in noble metal and has wide light absorption, high specific surface area and excellent carrier separation efficiency; when being applied to photocatalytic synthesis of nitric acid, nitrogen in air can be directly and efficiently converted into nitric acid under the mild conditions of room temperature, air atmosphere and water serving as a solvent, excellent durability is shown, the yield of nitric acid can reach 4466.2 mol g <-1 > cat after 324-hour continuous illumination, and wide application prospects are achieved in the field of green synthesis.

The invention provides a nitric acid production method with tail gas circulation. The method comprises the following steps: enriching feed air to form oxygen-enriched gas, and mixing the oxygen-enriched gas with high-pressure tail gas absorbed by a nitric acid absorption tower to obtain mixed gas; mixing the preheated mixed gas in the reactor with the gasified ammonia raw material, and oxidizing or reducing nitrogen oxides in the tail gas into NO2, N2O5 and N2; recovering high-grade heat in the process gas at the outlet of the reactor; process gas is subjected to gas-liquid separation, a gas phase is subjected to heat exchange, and a liquid phase enters a nitric acid absorption tower and faces a concentration tower plate. According to the method, unit consumption and energy consumption in the nitric acid production process can be reduced, NOx in tail gas emission is reduced, and the investment and operation cost in the nitric acid production process is reduced.

The invention provides a production device and process for recovering electronic-grade phosphoric acid from waste etching liquid. The device comprises a raw material storage tank, a multi-stage filtration system, a phosphoric acid evaporation kettle, a purification system, a mixed acid storage tank and a neutralization reaction and crystallization system. The waste etching liquid enters an evaporation kettle after being subjected to multi-stage filtration to remove suspended solid particles, and phosphoric acid is separated from volatile nitric acid and acetic acid; and condensing the volatile acid into mixed acid for storage, and removing metal ions from the semi-finished phosphoric acid through a purification system to obtain the electronic-grade phosphoric acid. The mixed acid reacts with alkali to generate a mixed solution of sodium acetate and nitric acid, sodium acetate crystals are separated out through evaporation and concentration, a solid product is obtained after separation, nitric acid is obtained by condensing gas, and suspended particles and metal impurities are subjected to incineration treatment. Through the steps of filtering, negative-pressure evaporation, neutralization and crystallization and the like, the process realizes efficient recovery of electronic-grade phosphoric acid and byproducts of sodium acetate and nitric acid, and has the characteristics of high resource recovery rate and low pollution emission.

The utility model discloses a nitric acid production unit and device, and relates to the technical field of nitric acid production equipment. The nitric acid production unit comprises an air compressor, a nitric oxide compressor, an expansion machine and a driving module, the driving module comprises a driving machine and at least two first-stage transmission shafts, the at least two first-stage transmission shafts are connected with the driving machine and provided with at least three first-stage connecting ends, and the first-stage connecting ends are connected with the driving machine. And the first-stage connecting end is correspondingly connected with one or two of the air compressor, the nitrogen oxide compressor and the expansion machine. The nitric acid production unit provided by the utility model is more compact in structure and smaller in size.

The invention relates to a method for a regeneration of a nitric acid, in which the used nitric acid is fed into a regeneration device that comprises a heated receiving tank B and a condenser C connected to it and a collection tank D, and where the regeneration is carried out in two stages. The nitric acid to be regenerated fed to receiving tank B in both the first stage and the second stage is heated under vacuum in receiving tank B in two separate heating cycles.

A burner basket assembly of an ammonia oxidation reactor, wherein the burner basket assembly comprises a burner basket inner side wall, a gas-permeable bottom plate, wherein between the burner basket inner side wall and the bottom plate a circumferential radial clearance is present, an L-shaped clearance cover profile which comprises a horizontal clearance cover plate and a vertical clearance cover plate which has a certain length, wherein the horizontal and the vertical clearance cover plate are mechanically fixed to each other, and wherein the L-shaped cover profile during operation is displaceable in a vertical direction in view of the burner basket inner side wall, a support ring which is mechanically fixed to the burner basket inner side wall, an upside-down positioned L-shaped locking profile, comprising a horizontal locking plate and a vertical locking plate which are mechanically fixed to each other, wherein the horizontal locking plate is mechanically fixed to the support ring, wherein the L-shaped locking profile, the support ring and the respective part of the burner basket inner side wall limit a ring-shaped gap into which at least a top part of the vertical clearance cover plate is located, and wherein between the support ring and the vertical clearance cover plate a distance is arranged which is such that the vertical displacement of the vertical clearance cover plate in view of the burner basket inner side wall is limited by the support ring and at all times during the operation of the burner basket, collision between the L-shaped clearance cover profile and the L-shaped locking profile is avoided.

The present disclosure provides system and method for synthesis of green ammonia and other nitrogenous fertilizers derived from it including urea and nitric acid (as well as others that may be produced by any combination / reaction of these) by coupling renewable energy and Carnot battery with Solid-Oxide Electrolyser Cell (SOEC) and Direct Air Capture (DAC). 5 The system provides a solution for round-the-clock renewable energy using Carnot battery that provides both heat and power to run SOEC. The heat from Carnot battery is used by DAC to capture carbon dioxide from air. A nitrogen-oxygen generator may produce nitrogen using continuous power from Carnot battery. Ammonia may be produced by using hydrogen from SOEC, and nitrogen from the nitrogen-oxygen generator. Urea may be produced using 0 carbon dioxide from DAC and ammonia. Ammonia and oxygen from SOECs and nitrogen- oxygen generator may be used for synthesis of nitric acid, and other nitrogenous fertilizers. The process heat from ammonia and nitric acid synthesis is recycled back to the Carnot battery.

This utility model discloses an energy-saving device for nitric acid recovery, including a demineralized water preheater. The outlet of the demineralized water preheater is connected to the inlet of a second demineralized water heater, and the outlet of the second demineralized water heater is connected to the inlet of a nitrogen oxide cooler. It also includes a nitrogen oxide compressor, the outlet of which is connected to the inlet of a first demineralized water heater, and the outlet of the first demineralized water heater is connected to the inlet of a rapid cooler. Furthermore, it includes a demineralized water boiler feed pump, the outlet of which is also connected to the inlet of the first demineralized water heater, the outlet of the first demineralized water heater, and the outlet of the second demineralized water heater, which is also connected to the inlet of the demineralized water preheater. Compared to existing technologies, this utility model adds two demineralized water heaters, recovering heat from nitrogen oxides through demineralized water, reducing the amount of circulating water used, and simultaneously reducing the amount of steam used in the steam drum.

The application belongs to the technical field of nitric acid decolorization, and particularly relates to a microelectronic nitric acid decolorization device, which comprises a decolorization barrel, a corrugated barrel is fixedly connected to the inner side of the decolorization barrel, a cavity is arranged between the decolorization barrel and the corrugated barrel, the cavity is divided into left and right cavities by two front and back partitions, an air outlet disc is fixedly connected to the bottom end of the corrugated barrel, the top end of the air outlet disc is fixedly connected to the bottom end of the decolorization barrel, a feed pipe is fixedly connected to the front left side of the top end of the decolorization barrel, an activated carbon pipe is fixedly connected to the left side of the top end of the feed pipe, an air inlet pipe one is fixedly connected to the rear left side of the top end of the decolorization barrel, a transmission box is fixedly connected to the middle side of the top end of the decolorization barrel, and transmission assemblies symmetrically arranged on the left and right sides of the transmission box are arranged on the outer side of the transmission box. The microelectronic nitric acid decolorization device provided by the application can solve the problem that the contact area is affected by the synchronous rotation of gas and liquid, and can also perform secondary reaction on the gas which is not completely reacted in the reaction process.

There is provided a method for the synthesis of nitrogen oxides (NOx) comprising the steps of providing a gas mixture comprising oxygen and nitrogen; and heating the gas mixture to a temperature of at least 2300 K at a pressure of 10-100 bar in a thermal reactor forming a gas mixture comprising NOx. There is also provided a method for the production of HNO3.

The utility model discloses a nitric acid preparation device for simulating an early atmospheric photochemical reaction of the earth. The nitric acid preparation device comprises an ultraviolet photochemical reaction system, a reaction gas source feeding system, a water vapor generator and a nitric acid freezing collector, the ultraviolet photochemical reaction system comprises an ultraviolet light source and a reaction chamber, and the ultraviolet light source is used for providing ultraviolet light required by reaction into the reaction chamber; the reaction gas source supply system is communicated with the reaction chamber and is used for supplying gas required for generating nitric acid through ultraviolet light chemical reaction into the reaction chamber; the water vapor generator is used for providing water vapor for the reaction chamber; the water vapor generator is connected with the reaction chamber; the nitric acid freezing collector is connected with the reaction chamber and is used for collecting nitric acid generated by photochemical reaction in the reaction chamber. The utility model realizes the preparation of nitric acid by simulating the early atmospheric photochemical reaction of the earth.

The utility model discloses waste heat recovery complete equipment for a small ammoxidation furnace, and belongs to the technical field of ammoxidation furnaces. The waste heat recovery complete equipment comprises a furnace end and a furnace body, the furnace end comprises a maneuvering device, a catalyst basket, an ignition device and a rotating device; the catalyst basket comprises four identical right-angle sectors, the linear edge of each right-angle sector wraps an L-shaped steel plate, the right-angle sectors are connected through bolts, welding bolts for lifting lugs are reserved in each right-angle sector, and the lifting lugs and the furnace end are of a bolt detachable structure. The catalyst basket is composed of four identical right-angle sectors, the length of each L-shaped plate is reduced, bending deformation in the later high-temperature using process due to the too long length is avoided, meanwhile, parts are conveniently maintained and replaced in a split mode, and resources are saved; a lifting lug of the catalyst basket adopts a bolt detachable structure, so that the catalyst net is convenient to mount and use; meanwhile, the catalyst baskets are connected through bolts, and welding bolts are reserved for lifting lugs of the catalyst baskets, so that later maintenance, replacement and lifting are facilitated.

This invention discloses a process for producing dilute nitric acid using a tail gas oxygenation cycle, belonging to the field of nitric acid preparation. First, the nitrogen-oxygen ratio is controlled to heat the nitrogen-oxygen mixture before it enters an ammonia mixer. The mixture undergoes ammonia oxidation in an oxidation furnace to produce NO. After recovering heat through a waste heat boiler, economizer, and demineralized water preheater, the mixture is cooled by a rapid cooler and then enters a dilute acid separator. The condensed dilute acid from the bottom of the separator is transported to an oxidation absorption tower. At the bottom of the oxidation absorption tower, NO is further oxidized to NO2 in the mixed gas. The remaining NO at the bottom of the oxidation absorption tower... x The mixed gas enters the upper part of the oxidation absorption tower through a baffle plate, where oxidation and absorption occur simultaneously. In the lower part of the absorption section, 55-60% dilute nitric acid is formed and flows to the upper part of the bleaching tower. After treatment in the bleaching tower, the finished acid flows out. The tail gas from the top of the oxidation absorption tower is pressurized by a booster and then enters an oxygen mixer for recycling. This invention solves the problem of tail gas pollution in nitric acid production, with low investment costs, high finished acid concentration, and low energy consumption.

The invention relates to a method for the catalytic oxidation of ammonia gas by means of an oxygen-containing gas, particularly by means of air, in the presence of a catalyst containing a noble metal, to form nitrogen monoxide, in which, according to the invention, the temperature of an ammonia-air mixed gas is adjusted before contact with the catalyst to a value that is optimum in terms of the nitrogen monoxide selectivity of the reaction. A more detailed observation of the process of the catalytic NH3 oxidation according to the above-mentioned reaction equation (I) 4 NH3 + 5 O2 → 4 NO + 6 H2O (I) would lead to the realisation that the optimum operating mode of a NH3-burner in a HNO3-installation is not achieved by maintaining a constant gauze temperature of the catalyst gauze by automatic adjustment of the NH3 : air ratio. Rather, there is an optimum temperature for each operating condition, which should not be adjusted by modifying the NH3 : air ratio, but by modifying the temperature of the NH3-air mixed gas before contact with the catalyst gauzes.

The invention provides a heat pipe enhanced heat exchange reducing absorption tower for nitric acid preparation, which comprises a tower body and a heat pipe exchanger, nitric oxide gas enters from the tower bottom, absorption liquid enters from the tower top, and the nitric oxide gas and the absorption liquid contact and react in the tower body to generate nitric acid, and is characterized in that the tower body is divided into a plurality of sections from top to bottom, the diameters of the sections are different, and the diameters of the sections are different in the direction from top to bottom; the diameter of the tower body is gradually increased; a plurality of heat pipe heat exchangers are arranged, an inclined angle is formed between the heat pipe heat exchangers and the tower body, an evaporation section of each heat pipe is arranged in the tower body, and a condensation end of each heat pipe extends out of the tower body. The design of the reducing absorption tower is matched with the concentration of nitrogen oxide, so that the absorption efficiency can be remarkably improved.

The present disclosure provides systems and methods for effecting chemical conversion using a plasma generating device. Advantageously, the plasma generating device is configured to directly deliver a plasma to fluid within a reservoir in a manner sufficient to create supersonic flow within the fluid. Such systems and methods can enhance reaction efficiency and convenience. A method of providing a point-of-use fertilizer composition is disclosed; the method comprising: introducing a gas feed stream comprising air into a plasma generating device; operating the plasma generating device to produce a plasma output comprising NOx compounds; injecting the plasma output through an outlet component into a reservoir having a fluid contained therein in a manner sufficient to create 5 supersonic flow within the fluid, wherein the outlet component is submerged within the fluid and wherein the fluid comprises water; withdrawing a liquid product stream from the reservoir; and optionally adjusting the pH of the liquid product stream for use as a point-of-use fertilizer composition.

A process and system are disclosed for producing lithium oxide from lithium nitrate. In the process and system, the lithium nitrate is thermally decomposed in a manner such that a fraction of the lithium nitrate forms lithium oxide, and such that a remaining fraction of the lithium nitrate does not decompose to lithium oxide. The thermal decomposition may be terminated after a determined time period to ensure that there is a remaining fraction of lithium nitrate and to thereby produce a lithium oxide in lithium nitrate product. The lithium oxide in lithium nitrate product may have one or more transition-metal oxides, hydroxides, carbonates or nitrates added thereto to form a battery electrode. The lithium oxide in lithium nitrate product may alternatively be subjected to carbothermal reduction to produce lithium metal.

The catalyst support system (1) for the ammonia oxidation burner (2) comprises a catalytic gauze for the oxidation of ammonia and a basket (14) connected to a support ring (10) for holding an inert substance and / or a catalyst for removing N2O from the gaseous effluent of this catalytic gauze (9), this basket (14) having a modular structure comprising a plurality of modules, each module comprising a gas-permeable surface (16) and a support frame (15), each module being connected to an adjacent module by a connection configured to allow limited displacement between the modules, and only the outer modules forming the periphery of the basket being connected to the support ring (10).

The invention discloses a novel process for joint production of concentrated nitric acid and dilute nitric acid. The novel process comprises the procedures of N2O4 separation, absorption, rectification, oxidation and bleaching. The N2O4 separation is to separate liquid N2O4 from the NOX gas produced by a double-pressurization method; the absorption is that NOX which is not completely separated is absorbed to generate dilute nitric acid; in the rectification step, dilute nitric acid generated by absorption is concentrated to obtain a finished product dilute nitric acid; in the oxidation step, dilute nitric acid, liquid N2O4 and oxygen are subjected to a reaction to generate concentrated nitric acid, and in the bleaching step, impurities in the concentrated nitric acid are removed to obtain the finished product concentrated nitric acid. By technically improving the nitric acid device adopting the double-pressurization method, the concentrated nitric acid and the dilute nitric acid can be co-produced, the production cost of the concentrated nitric acid and the dilute nitric acid can be effectively reduced, a new concentrated nitric acid production device is not needed, and the existing production line is improved at low cost. In addition, the yield of concentrated nitric acid and dilute nitric acid can be controlled by controlling the separation amount of N2O4.

A method for reducing the NOx emission during start-up and shutdown events of a nitric acid plant, wherein the nitric acid plant comprises a tail gas treatment section (10) including a first catalytic bed (2) for removal of N2O followed by a second catalytic bed (3) for removal of NOx, wherein during a start-up or shutdown the operation of said treatment section (10) is temporarily modified by adding a NOx reducing agent (4) upstream of said first catalytic bed (2), so that said first catalytic bed (2) provides reduction of NOx.

[Problem] To provide a nitrogen fixation method and a nitrogen fixation device which are capable of significantly reducing energy and cost and are easy to put into practical use. [Solution] According to the present invention, water 14, which is brought into contact with air and has dissolved the air, is brought into contact with a photocatalyst (photocatalyst layer 5), and the photocatalyst is irradiated with ultraviolet rays (light source 91), and thus ammonia, nitric acid, or nitrous acid is generated in the water 14 from nitrogen molecules in the air dissolved in the water 14 by a photocatalytic reaction.

This invention discloses a waste acid recovery method based on ion exchange separation technology, belonging to the field of waste acid recovery technology. The method includes the following steps: passing a waste nitric acid solution containing aluminum and chloride ions through a cation exchange resin to adsorb aluminum ions; adding silver nitrate solution to the adsorbed waste liquid to allow silver ions to react with chloride ions to form silver chloride precipitate; filtering out the silver chloride precipitate to obtain a nitric acid solution; removing the silver chloride precipitate, using aluminum foil as a reducing agent, and adding a small amount of hydrochloric acid to reduce the silver chloride to silver powder; washing the reduced silver powder and dissolving it in nitric acid to obtain a silver nitrate solution for recycling. This waste acid recovery method based on ion exchange separation technology solves the problem of excessive total nitrogen in wastewater discharge; it also significantly reduces waste acid treatment costs and improves economic efficiency.

Process for the synthesis of nitric acid comprising a catalytic oxidation step of an ammonia feed in the presence of an oxidant to yield a nitrogen oxide-containing gas, an absorption step of said nitrogen oxide-containing gas in water to produce nitric acid and a tail gas, wherein said oxidant is subjected to multiple compression steps prior to said oxidation step, said multiple compression steps comprise at least a first compression step and a second compression step, wherein inter-cooling is carried out between said compression steps, wherein said inter-cooling comprises a first cooling step in which the compressed oxidant is cooled with a cooling medium selected from a stream of tail gas, a demineralised water stream, or at least a portion of said ammonia feed.