185 results about "Oxidized nitrogen" patented technology

Systems and methods for producing nitrates, nitric acid, salts thereof, or a mixture thereof are disclosed. The systems may include a feed conduit configured for receiving a feed stream comprising molecular oxygen and molecular nitrogen; an inlet conduit configured for receiving an inlet stream; a plasma reactor fluidically coupled to the inlet conduit, the plasma reactor fluidically coupled to a reactor-outlet conduit configured for receiving the reactor-outlet stream, the plasma reactor configured to produce oxidized nitrogen species; and an absorber fluidically coupled to the reactor-outlet conduit, the absorber configured to receive the reactor outlet stream and to produce nitrates, nitrites, nitric acid, salts thereof, or a mixture thereof from the reactor outlet stream. A recycle conduit may be fluidically coupled to the absorber and the inlet conduit, wherein the recycle conduit is configured to receive the gas-phase stream from the absorber and provide the gas-phase stream to the inlet conduit.

The invention relates to the technical field of environmental monitoring, and discloses a method for reconstructing carbon dioxide concentration enhancement based on multi-source satellite data, which comprises the following operation steps: collecting environmental information such as carbon dioxide dry air column concentration, nitrogen dioxide total column concentration, population density, land utilization, weather and the like to construct an environmental database; pre-processing the collected multi-source data to ensure time-space consistency; according to the population density of the region, the total column concentration of nitrogen dioxide and the land utilization type, setting a threshold value, and dividing the target region into a discharge region and a background region; constructing a background concentration reconstruction model, inverting the carbon dioxide background concentration, and calculating a residual error with actually measured carbon dioxide to obtain a carbon dioxide concentration enhanced sample; based on the carbon dioxide concentration enhanced sample, a concentration enhanced reconstruction model is constructed, and high-resolution carbon dioxide concentration enhanced spatial-temporal distribution is obtained. According to the method, high-frequency monitoring of the carbon source in the region can be realized spatially, and powerful support is provided for dynamic tracking of carbon emission.

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 discloses a coal bunker mixed gas concentration detection method based on a BSA algorithm and a BP neural network, and belongs to the technical field of gas detection. The coal bunker mixed gas concentration detection method based on the BSA algorithm and the BP neural network comprises the following steps: collecting gases including carbon monoxide, nitrogen dioxide, sulfur dioxide, hydrogen sulfide and methane, and constructing the BP neural network by taking normalized gas data as an input layer; and optimizing BP neural network parameters by using a BSA bird flock algorithm, carrying out network training by using a back propagation algorithm, and inputting gas concentration data collected in real time into the trained neural network in real time to obtain a predicted value of the gas concentration. According to the method, the parameters of the BP neural network are optimized through the BSA algorithm, the accuracy of network prediction is greatly improved, the gas concentration in the coal storage bunker can be monitored in real time, and once it is detected that the hazardous gas concentration exceeds the standard, quick response can be made and corresponding measures can be taken, so that potential safety risks are reduced.

The invention relates to the technical field of automobile air purification, and particularly discloses a filtering material, a preparation method of the filtering material and a novel automobile air conditioner multi-effect catalytic formaldehyde removal filter. The filtering material comprises a PET (Polyethylene Terephthalate) supporting layer, a gas filtering layer and a PP (Polypropylene) electrostatic filtering layer which are arranged in sequence, the gas filtering layer is prepared from the following raw materials in parts by weight: 30 to 90 parts of activated carbon and 10 to 70 parts of manganese catalyst. The gas filtering layer composed of the activated carbon and the manganese catalyst is matched with the filtering material composed of the PET supporting layer and the PP electrostatic filtering layer, four gases of n-butane, methylbenzene, sulfur dioxide and nitrogen dioxide can be adsorbed, the manganese catalyst degrades formaldehyde at normal temperature, meanwhile, the reaction on the formaldehyde is a catalytic reaction, and the environment-friendly effect is achieved. Therefore, the filter material disclosed by the invention also has longer service life, so that a filter made of the filter material has a better formaldehyde removal effect and longer service life.

The invention relates to the technical field of chemical synthesis, and discloses a method for preparing short-chain diacid by catalytic oxidation of polyethylene with an ionic liquid, which comprises the following steps: mixing the ionic liquid and polyethylene, and mixing for oxidation reaction in the presence of nitric oxide and oxygen to obtain the short-chain diacid. According to the method, the polyethylene is adopted as the raw material for the first time, the ionic liquid is used as the reaction catalyst and the reaction medium, nitric oxide is catalyzed to generate nitrogen dioxide, efficient catalytic oxidation of the polyethylene is achieved, the short-chain diacid product with the carbon number of 4-12 is obtained, the highest yield reaches 90% or above, and the influence on the yield is not large when the polyethylene recycled material is adopted. The method not only solves the problem of polyethylene waste recovery, but also solves the problem of high preparation cost of short-chain diacid, so that the preparation cost is greatly reduced.

The present application discloses a sludge treatment slow-release material and a treatment method, and belongs to the technical field of sludge treatment. A water-soluble coating material forms a slow-release film on the surface of an iron-carbon micro-electrolysis filler, and the slow-release film slowly dissolves in the sludge to slowly release the iron-carbon micro-electrolysis filler. The iron-carbon micro-electrolysis filler undergoes a galvanic cell reaction in the sludge, and the generated divalent iron ions can catalytically activate persulfate to produce persulfate radicals and trivalent iron ions. The persulfate radicals can oxidize nitrogen-containing organic matter, and the trivalent iron ions react with phosphates to generate iron phosphate precipitates; the dissolved water-soluble coating material complexes with heavy metals, thereby achieving the purpose of removing nitrogen-containing organic matter, phosphorus-containing organic matter and heavy metals in the sludge. The slow-release material can slowly release the iron-carbon micro-electrolysis filler, thereby continuously producing stable divalent iron ions, prolonging the active time of persulfate, and then prolonging the treatment time of the slow-release material on the sludge, achieving the purpose of long-term repair.

According to the anti-oxidation UN-based composite fuel pellet and the preparation method thereof, silicon carbide (SiC) serves as an anti-oxidation performance reinforcing phase of the UN fuel pellet, SiC is distributed in a dispersed mode or continuously distributed in a UN fuel matrix in a three-dimensional mode, and by means of the intragranular-grain boundary synergistic reinforcing effect of SiC, the anti-oxidation UN-based composite fuel pellet can be used for preparing the anti-oxidation UN-based composite fuel pellet, and the anti-oxidation UN-based composite fuel pellet can be used for improving the anti-oxidation performance of the UN fuel pellet. And the oxidation resistance of the UN fuel pellet is remarkably improved. Intragranular modification generated by solid solution reaction of trace SiC and UN can effectively enhance intrinsic oxidation resistance of a UN matrix, and meanwhile, excellent chemical inertness of a second phase of SiC can effectively inhibit grain boundary oxidation. By optimizing the morphology and distribution mode of the SiC second phase in the composite fuel pellet, the oxidation resistance of the composite fuel pellet can be further improved.

The invention discloses a process and a device for recycling nitrogen dioxide, which are characterized in that degassed crude dimethyl sulfoxide is used as a raw material, nitrogen dioxide is absorbed by two stages of crude dimethyl sulfoxide and enters a micro-channel reactor to be used as a catalyst for oxidizing dimethyl sulfide, and recycling is realized. The device comprises a tail gas absorption unit, a microreactor unit, a heat exchanger unit and a separator unit, the technology adopts a dimethyl sulfoxide low-temperature absorption technology, and has the advantages of cyclic utilization of nitrogen oxides, energy conservation and emission reduction, convenience in operation, greenness, high efficiency and the like.

The utility model discloses a diesel generator flue gas purification mechanism for civil air defence engineering, including air inlet pipe and purification bin, the air inlet pipe one end is linked with diesel generator exhaust pipe in civil air defence engineering power generation room intercommunication, the other end of air inlet pipe is inserted into the purification bin and the opening direction is perpendicular to downward, the open end position of air inlet pipe in the purification bin is connected with the shunt joint, each interface of shunt joint all is connected with the jet pipe that the air hole of pipe body lateral wall is evenly set up, the utility model relates to civil air defence engineering technical field, utilize liquid supply booster pump and press into the spray subassembly in alkaline solution (15% magnesium hydroxide compound agent), and further via spray subassembly to the spray of filler layer, make the nitrogen monoxide, nitrogen dioxide, sulfur dioxide and particulate matter etc. in tail gas contact with the alkaline water mist in purification bin and filler layer, to the purification treatment of nitrogen monoxide, nitrogen dioxide, sulfur dioxide and particulate matter.

The invention provides an In2O3 carrier material, a preparation method of the In2O3 carrier material, a sensitive sensing assembly and application of the sensitive sensing assembly. The preparation method of the In2O3 carrier material comprises the following steps: S1, firstly synthesizing MIL-68 by an oil bath method, and then performing oxidation treatment to obtain an In2O3 nanorod; and S2, putting the In2O3 nanorod into a high-speed nitriding furnace, and carrying out nitriding treatment in an ammonia gas atmosphere, so as to obtain the In2O3 carrier material. The porous MIL-68 is subjected to oxidation treatment to derive the In2O3 nanorods, and then nitridation treatment is performed to regulate and control the nitrogen-oxygen ratio of the In2O3 carrier material, so that the crystal structure of In2O3 is optimized, and the sensitivity and selectivity of In2O3 to nitrogen dioxide are improved. In the fuel cell type gas sensor, the sensitive sensing assembly made of the In2O3 carrier material has high sensitivity and selectivity to low-concentration nitrogen dioxide, and has the advantages of high response speed, short recovery time, high stability, good moisture resistance and the like.

The utility model discloses a reaction device for normal-pressure leaching of nitric acid, which is characterized in that in the reaction process, nitric oxide in a reaction kettle enters an absorption tower through a nitric oxide exhaust outlet, a first pipeline and a nitric oxide gas inlet, and an oxygen supply device supplies oxygen to the absorption tower; an absorption liquid circulating pump I conveys an absorbent in the absorption tower circulating device to an absorbent circulating inlet I and enters the absorption tower, the absorbent absorbs nitric oxide gas to form nitric acid, nitric oxide released in the process reacts with oxygen to generate nitrogen dioxide, and the nitrogen dioxide reacts with the absorbent to generate nitric acid; according to the device, nitrogen oxide gas generated in the reaction process can be absorbed, the obtained absorption acid (nitric acid) can be cyclically applied to the leaching reaction, and tail gas can be discharged after reaching the standard. And the method is environment-friendly.

The invention relates to a method for producing an electrochemical cell, preferably a fuel cell, in particular a PEM fuel cell, in which a catalyst material is deposited on a carbon-based support material having a porous structure in order to form an electrode of a membrane-electrode assembly and the carbon-based support material is subsequently subjected to a thermal post-treatment, the carbon-based support material is selectively oxidized by means of a reaction gas containing at least one reactant, preferably carbon dioxide (CO2), ammonia (NH3), nitrogen dioxide (NO2), nitrogen monoxide (NO) and / or water vapor (H2O). The invention also relates to an electrochemical cell, preferably a fuel cell, in particular a PEM fuel cell.

The present invention relates to a process for removing nitrogen oxides, nitrous oxide and carbon monoxide from a gas stream (1), comprising: (a) oxidizing nitric oxide in the gas stream to form nitrogen dioxide by adding an oxygen-containing gas (3) to the gas stream (1), thereby obtaining a nitric oxide-depleted gas stream, and washing the nitric oxide-depleted gas stream with water (7) to obtain a nitric oxide-depleted gas stream (11) to remove nitrogen oxides from the gas stream (1); (b) oxidizing at least a portion of the carbon monoxide in the nitrogen oxide-depleted gas stream (11) to form carbon dioxide, thereby obtaining a carbon monoxide-depleted gas stream (19); (c) converting nitrous oxide in the carbon monoxide-depleted gas stream (19) to nitrogen and oxygen if the carbon monoxide-depleted gas stream (19) does not contain carbon monoxide, or converting nitrous oxide in the carbon monoxide-depleted gas stream to nitrogen and oxygen and / or carbon dioxide if the carbon monoxide-depleted gas stream (19) still contains carbon monoxide, or converting nitrous oxide in the carbon monoxide-depleted gas stream (19) to nitrogen and oxygen and / or carbon dioxide if the carbon monoxide-depleted gas stream (19) still contains carbon monoxide; to obtain a purified tail gas stream (25).

The utility model relates to the technical field of dilute nitric acid production, in particular to a dilute platinum nitrate net precious metal recovery device which comprises a baffle, a guide cover fixedly connected to the interior of the baffle, an exhaust pipe fixedly connected to the center of the guide cover, a communicating pipe communicated with one side of the exhaust pipe, and a plurality of bending parts installed on the outer side of the communicating pipe. The other ends of the bent parts are fixedly connected with transverse parts, and the other ends of the transverse parts are arranged in a sealed mode. Laminated filtering materials are wound on the outer sides of the bent part and the transverse part; when the gas filter is used, mixed gas such as nitric oxide gas needing to be filtered enters the shell through the gas inlet connector and is filtered through the filtering material, metal particles are attached to the surface of the filtering material, and the gas enters the shell through the through holes in the surfaces of the transverse part and the bent part and is exhausted through the exhaust pipe. When the dilute nitric acid device is shut down and the platinum net is replaced, the new filter element is synchronously replaced, precious metal particles in the old filter element are recycled, and precious metal lost from the platinum net of the oxidizing furnace is continuously recycled in the dilute nitric acid production process.

The invention belongs to the technical field of nano sensing and gas monitoring, and discloses an MXene / ZnO nano composite material as well as a preparation method and application thereof. The preparation method comprises the following steps: firstly, etching Ti3AlC2 by using hydrochloric acid and lithium fluoride to obtain multi-layer two-dimensional MXene, and then carrying out ultrasonic stripping and freeze drying to obtain few-layer MXene; carrying out alkalization treatment on few layers of MXene, and then carrying out centrifugal cleaning to obtain 1D / 2D-MXene with a composite structure; the preparation method comprises the following steps: adding 1D / 2D-MXene and zinc acetate dihydrate into a mixed solution of water and ethanol, and carrying out a hydrothermal reaction; the preparation method comprises the following steps of: performing centrifugal cleaning and vacuum drying to obtain a multi-level 1D / 2D-MXene / 0D-ZnO nano-composite structure consisting of 0D-ZnO, 1D-MXene and 2D-MXene, and the multi-dimensional nano-composite structure is suitable for preparing a gas sensor and is used for detecting low-concentration nitrogen dioxide gas at room temperature. The nano composite material and the sensor prepared by the invention show excellent gas-sensitive performance on nitrogen dioxide gas, are high in sensitivity, can realize normal-temperature detection, and have relatively great application potential.

The invention provides a safety protection method, device and equipment in a cockpit and a readable storage medium, the method comprises the following steps: receiving various index information monitored by a sensor, the various index information comprising concentrations of a plurality of gases in formaldehyde, nitrogen dioxide, oxygen and carbon monoxide; corresponding safety protection measures are matched and executed according to the standard reaching conditions of the various index information, the flameout state of the vehicle and the biological conditions in the vehicle, and the biological conditions comprise the character conditions and the animal conditions. According to the method, the effects of accurately detecting the safety in the vehicle and carrying out the safety protection process in time can be achieved.

The invention discloses a nitric oxide backdraft balance test device which comprises a plasma generation furnace, a cooler, a first detection device and a second detection device, the plasma generation furnace is used for heating nitrogen and oxygen to enable the nitrogen and the oxygen to generate nitric oxide at high temperature, a thermal medium inlet is communicated with a gas outlet, and a gas inlet is communicated with a gas outlet. The cooler is used for cooling gas discharged by the plasma generator; the first detection device is used for detecting the content of nitric oxide entering the plasma generation furnace, and the second detection device is used for detecting the content of cooled nitric oxide discharged by the cooler. The nitric oxide backdraft balance test device can be used for studying backdraft balance of thermal nitric oxide, technical support is provided for reducing the content of nitric oxide in flue gas of a coal-fired boiler, the boiler emission control technology can be further optimized, near-zero emission of the coal-fired boiler can be achieved, and environmental pollution can be reduced.

The invention discloses a porous crystal material for air purification and a preparation method and application thereof. The crystal material belongs to a tetragonal system, the space group is P43212, the simple formula of the chemical structure is [Ni (Htbc) (fdpy) (H2O)], the molecular formula is C54H42NiN2O7, and the cell parameter is # imgabs0 # alpha = beta = gamma = 90 degrees; the prepared crystal material has a clear space structure and an accurate molecular formula, has good adsorption performance on harmful gas micromolecules, is used as a porous crystal material for removing harmful gas pollutants such as formaldehyde, acetylene, ethylene, halogenated hydrocarbon, nitric oxide, nitrogen dioxide, ammonia or sulfide and the like for air purification, and has a wide application prospect. The technology has the advantages of simplicity in operation, low cost, stable performance, suitability for large-scale production and the like.

Flue gas pollutants are particulate matter, gaseous pollutants, and other harmful substances generated during the combustion of fossil fuels (such as coal, oil, natural gas). These pollutants include PM2.5, PM10, sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and volatile organic compounds (VOCs), which pose serious hazards to the environment and human health. The present invention proposes a method for predicting the generation amount of flue gas pollutants, which is predicted by the constructed T3N model and smooth loss function. This method can accurately master the data of flue gas generation amount, thereby realizing the real-time regulation and optimization operation of pollutant sources, and providing more effective means for environmental protection and pollution control.

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.

There is provided a method for analyzing gas containing nitrosyl fluoride capable of highly accurately and safely quantitatively determining oxygen gas and nitrogen gas contained in mixed gas containing nitrosyl fluoride and at least one of the oxygen gas and the nitrogen gas. The method for analyzing gas containing nitrosyl fluoride includes: a conversion step of bringing the mixed gas into contact with a reactant reacting with the nitrosyl fluoride to generate nitrogen oxide, and converting the nitrosyl fluoride into the nitrogen oxide by a reaction between the nitrosyl fluoride and the reactant; a removal step of bringing the gas after the conversion step into contact with an adsorbent adsorbing the nitrogen oxide, and removing the nitrogen oxide from the gas by the adsorption of the nitrogen oxide; and an analysis step of analyzing the gas after the removal step and quantitatively determining the oxygen gas and the nitrogen gas.

The invention discloses a method for relieving and eliminating sewage anaerobic fermentation stink. The method comprises the following steps: mixing malodorous gas generated by anaerobic fermentation with nitrogen dioxide, and carrying out gas-phase oxidation reaction; the reacted gas is subjected to ultraviolet photolysis treatment, so that nitrogen dioxide is decomposed to generate ozone; and the generated ozone is utilized to continuously oxidize the malodorous substances. The method can also comprise a source sulfur fixation step: adding a sulfur fixation agent into the anaerobic fermentation system, and reducing the generation of hydrogen sulfide from the source. Nitrogen dioxide can be prepared from steel cylinder gas, industrial waste gas or on site, and the on-site preparation comprises an ammonia water / ammonium salt catalytic oxidation method and a nitric acid reduction method. Through multi-stage cooperation of'source sulfur fixation + NO2 gas-phase oxidation + UV ozone conversion + ozone continuous oxidation ', efficient removal of malodorous gas is achieved, an ozone generator does not need to be additionally arranged, nitrogen dioxide residues are thoroughly eliminated, secondary pollution is avoided, equipment is compact, and the operation cost is low.

The utility model relates to a nitric acid waste heat power generation energy comprehensive utilization device which comprises an oxidation furnace, a back pressure steam turbine, a power generator, a nitric oxide compressor, an air compressor and a waste heat boiler. A high-pressure steam pipeline of the oxidation furnace is connected with a steam inlet of the back-pressure steam turbine, an output shaft of the back-pressure steam turbine is connected with the generator, the generator is used for supplying power to a high-pressure power distribution system of the unit, and a steam outlet of the back-pressure steam turbine is communicated with a first low-pressure steam pipeline; a nitric oxide gas pipeline of the oxidation furnace is connected with the nitric oxide compressor, an output shaft of the nitric oxide compressor is connected with an input shaft of the air compressor, and a gas outlet of the air compressor is connected with an air inlet of the waste heat boiler; and an air pipeline of the waste heat boiler is communicated with an air inlet of the oxidizing furnace. The device recycles steam, saves energy, is beneficial to energy conservation and emission reduction, and is environment-friendly.

The application discloses a river nitric oxide emission calculation method based on a land-river-air simulation, and belongs to the field of environmental engineering. The existing method for measuring river N2O has poor accuracy. A RF regression model is trained by using a nitrogen emission prediction set, a geographical variable prediction set and a climate variable prediction set, and a trained RF regression model is obtained. The nitrogen emission test set, the geographical variable test set and the climate variable test set are input into the trained RF regression model, and the river water concentration of each sub-basin in each region is output. The river hydrological parameters of each sub-basin in each region and the river water concentration of each sub-basin are input into an air-water interface gas exchange model, and the total river nitric oxide emission of each sub-basin in each region is obtained. The application is used for obtaining the total river nitric oxide emission.

The invention discloses a nano spherical SnPd oxide, which is prepared by the following steps: firstly, cross-linking tannic acid and formaldehyde at room temperature by taking F127 as a surfactant, then adding stannous sulfate and palladium nitrate dihydrate for chelation, carrying out hydrothermal reaction to obtain a SnPd phenolic hybrid, and finally, calcining to obtain the nano spherical SnPd oxide, namely SP for short. SP is an n-type semiconductor, and the chemical composition of SP is SnO2 and Pd; the diameter of the mesoporous nanosphere is 100-150nm, and the average pore size of the mesoporous nanosphere is 5-7nm. The preparation method comprises the following steps: 1, preparing the SnPd phenolic hybrid SPZ; 2, preparation of an SnPd oxide SP; according to the SP-based hydrogen sensor and the preparation method thereof, the response value is 14.6, the response time is 1.5-2 seconds, the recovery time is 7-10 seconds, and the minimum hydrogen concentration detection is 0.2 ppm; the cycling stability reaches 30 days; the catalyst has selectivity on ammonia gas, methane, carbon dioxide, carbon monoxide and nitrogen dioxide.

The invention relates to the technical field of adsorbents, in particular to a multi-element gas adsorbent as well as a preparation method and application thereof. The preparation method of the multi-element gas adsorbent provided by the invention is simple, economic and environment-friendly, and is suitable for industrial large-scale production. The prepared adsorbent is regular in morphology and rich in various active sites, and sulfur dioxide, nitrogen dioxide and ammonia gas in air can be effectively adsorbed. Compared with the prior art, the CHO-SBA-PEI multi-element gas adsorbent prepared by the preparation method disclosed by the invention combines a mesoporous structure (high specific surface area and regular pore channels) of SBA-15, amino active sites of PEI and aldehyde groups modified in the pore channels of SBA-15, not only realizes multi-element absorption of SO2, NO2 and NH3, but also has high adsorption capacity, and can effectively purify gas entering a hydrogen energy fuel cell. The preparation process is simple and controllable, does not need special equipment, is easy for large-scale production, and is suitable for industrial application of the hydrogen energy fuel cell air filter.

The present invention relates to a method for removing nitric oxide, nitrogen dioxide, and nitrous oxide from an exhaust gas stream obtained during nitration, the method comprising: (a) removing nitric oxide and nitrogen dioxide from the exhaust gas stream by adding an oxygen-containing gas to the exhaust gas stream to oxidize the nitric oxide in the gas stream to form nitrogen dioxide, thereby obtaining a nitric oxide-deficient gas stream; (b) washing the nitric oxide-deficient gas stream with water to obtain a nitric oxide- and nitrogen dioxide-deficient gas stream; and (c) converting the nitrous oxide in the nitric oxide- and nitrogen dioxide-deficient gas stream 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 relates to a method for operating a drive unit (1) for a motor vehicle, which has a drive unit (2) that generates exhaust gas and is designed as a gasoline internal combustion engine, as well as an exhaust gas aftertreatment device (4) for aftertreating the exhaust gas with a first vehicle catalyst (5) and a second vehicle catalyst (6) connected in series with the first vehicle catalyst (5) in terms of flow technology.The invention provides that, after operating the drive unit (2) with a lean fuel-air mixture for a specific first period, the drive unit (2) is operated with a rich fuel-air mixture for a specific second period to adjust the actual fill level of an oxygen storage element of the first vehicle catalyst (5) towards a target fill level selected to reduce nitrogen oxide emissions from the drive unit (1). The second period is selected based on at least one state variable of the vehicle catalysts (5, 6) to reduce ammonia emissions from the drive direction (1). The invention further relates to a drive unit (1) for a motor vehicle and a computer program.

The invention discloses a ship tail gas desulfurization and denitration catalytic treatment device and method.The device comprises a heat exchange oil tank, a desulfurization tower, a denitration tower and an SCR denitration reactor, a first heat exchange coil pipe is arranged in the heat exchange oil tank, and a tail gas exhaust pipe of a ship diesel engine is connected with a three-way valve; one outlet of the three-way valve is connected with a first heat exchange coil pipe through a pipeline, the other outlet of the three-way valve is connected with a heat exchanger through a pipeline, the heat exchanger and the first heat exchange coil pipe are connected with an air inlet header pipe of a desulfurizing tower through pipelines, and a plurality of first spraying heads are arranged in the desulfurizing tower and connected with a first booster pump through pipelines; the first booster pump is connected with an alkali liquor tank through a pipeline; the bottom of the desulfurizing tower is communicated with an alkali liquor recycling tank through a pipeline. Compared with a traditional treatment mode that sulfur dioxide and nitric oxide need to be completely oxidized into sulfur trioxide and nitrogen dioxide, the method only needs to oxidize part of nitric oxide, energy is saved, and meanwhile treatment reagents can be saved.