266 results about "Low temperature combustion" patented technology

The invention discloses a preparation method of a lithium ion battery negative electrode material spinel porous high-entropy oxide material, and belongs to the field of inorganic oxide powder materials. The method is a low-temperature combustion synthesis method, and specifically includes the steps that metal nitrate is adopted as a metal source, one or a mixture of several of tartaric acid, citric acid, glucose, hexamine and ethylenediaminetetraacetic acid is used as a fuel, and by controlling the concentration of the metal salt raw material, the kind and the amount of the fuel, the kind andthe amount of a combustion improver and an ignition mode, characteristics of the grain size, the shape and the like of spinel ransition metal high-entropy oxide nano-powder are adjusted and controlled. According to the preparation method of the lithium ion battery negative electrode material spinel porous high-entropy oxide material, liquid-phase ingredients are adopted, molecular-level even mixing of the raw materials is ensured, and a stoichiometric ratio of the product is achieved; meanwhile the preparation method of the lithium ion battery negative electrode material spinel porous high-entropy oxide material has the advantages of being energy-saving, high in production efficiency, environmentally friendly, free from complex post-treatment and the like, and the prepared high-entropy oxide powder is high in purity, small in grain size and even in distribution, and has high initial discharge capacity and good cycle performance.

The invention provides a preparation method of rare earth oxide doped tungsten powder, belonging to a technical field of rare earth refractory metal material. The process flow is that: firstly, a precursor powder is obtained by adopting low-temperature combustion synthesis, wherein the precursor powder is a uniform mixture of rare earth oxide (at least one of Sc2O3, Y2O3, La2O3, CeO2, ZrO2, Gd2O3and Eu2O3) and tungsten oxide; secondly, the precursor powder undergoes calcination in a muffle furnace; lastly, two-step reduction is carried out in the atmosphere of hydrogen or dissociated ammonia. Easy-reduction tungsten oxide is reduced to tungsten matrix powder, and the rare earth oxide that can not be reduced is reserved, thereby the rare earth oxide doped tungsten powder is obtained. The content of the rare earth oxide in the rare earth oxide doped tungsten powder is 0.05-35 wt%. The advantage of the invention is that target element and organic carbon source are capable of forming a highly dispersed system, and particle sizes of the obtained oxide are uniform and fine. The method is suitable for industrialization production because of low cost of raw materials, quick reaction speed, low energy consumption and simple technology.

Belonging to the field of inorganic oxide powder materials, the invention discloses a preparation method of a spinel-type porous high entropy oxide material. The method is low temperature combustion synthesis method. Specifically, a metal nitrate is adopted as the metal source, one of or a mixture of several of citric acid, ethylenediamine tetraacetic acid, hexamethylenetetramine and glucose is adopted as the fuel, by controlling the concentration of the metal salt raw materials, the fuel type and adding amount, the combustion improver type and adding amount, and the ignition way, the granularity, morphology and other characteristics of the spinel-type transition metal high entropy oxide (CoCrFeMnNi)3O4 nanopowder can be regulated. The preparation method adopts liquid phase compounding toensure molecular level uniform mixing of the raw materials, and the product achieves stoichiometric ratio. At the same time, the method has the advantages of energy saving, high production efficiency,green and environmental protection, no need for complicated post-treatment and the like. The high entropy oxide powder prepared by the method provided by the invention has high purity and uniform particle size distribution.

Removal of fine particles by oxidation or/and sulfur poisoning recovery control may be required when an internal combustion engine has been in an extremely low load state for a predetermined period or more. In this case, the engine speed of the internal combustion engine (1) is adjusted to a range where the temperature of a filter (20) can be raised by heat-up control. The heat-up control is then executed by a filter temperature control means to raise the temperature of the filter (20) to a predetermined value. When the filter (20) reaches the predetermined temperature by means of low-temperature combustion, post-injection, VIGOM-injection, addition of 10 fuel to an exhaust system and the like, removal of fine particles by oxidation or/and sulfur poisoning recovery control for eliminating sulfur poisoning of a NOx absorbent are conducted. Removal of PMs captured by the filter and sulfur poisoning recovery control of the NOx absorbent can thus be conducted even if the internal combustion engine is left in an extremely low load operational state.

This invention detects the crank angle location where combustion switches from premixed to diffusion, referred to as the transition index, and uses that location to define integration limits that measure the portions of heat released during the combustion process that occur during the premixed and diffusion phases. Those integrated premixed and diffusion values are used to develop a metric referred to as the combustion index. The combustion index is defined as the integrated diffusion contribution divided by the integrated premixed contribution. As the EGR rate is increased enough to enter the low temperature combustion regime, PM emissions decrease because more of the combustion process is occurring over the premixed portion of the heat release rate profile and the diffusion portion has been significantly reduced. This information is used to detect when the engine is or is not operating in a low temperature combustion mode and provides that feedback to an engine control algorithm.

Disclosed is a catalytic filter for removing soot particulates from diesel engine exhaust, which is comprised of monolithic oxidation catalyst upstream of the catalytic filter, which effectively oxidize gaseous pollutants and volatile organic fractions, and a catalyzed wall-flow filter downstream serving to low temperature combustion of soot particulates collected on the filter. Also, the preparation method of the catalytic filter is provided, including the colloidal mixture solution of platinum group metal salts and other metal salts with a water-soluble polymer and a reducing agent, which is then impregnated on a catalyst support, followed by calcining at high temperatures. In the present invention, use of the catalytic filter provides effective means of abating diesel exhaust pollutant emissions, that is, particulate matter (PM) and gaseous pollutants (HC, CO, NOx).

A method of fueling an internal combustion engine including operating the internal combustion engine in a dual-fuel mode in which the engine is fueled by a pre-mixed charge of fresh air, recirculated exhaust gases, gaseous fuel as primary fuel and early injected liquid fuel as a secondary fuel, ignited by a late injected pilot fuel to provide low temperature combustion. The method further includes adjusting EGR and/or fresh airflow to the engine to maintain peak in-cylinder temperature in a desired range, preferably between 1500 K and 2000 K. EGR preferably is controlled to obtain a desired in-cylinder O₂ mole fraction, and fresh airflow preferably is controlled to obtain a desired fresh air lambda.

The invention provides a six-element high-entropy oxide material for a lithium ion battery and a preparation method, and relates to the technical field of entropy oxide materials. The chemical formulaof the six-element high-entropy oxide powder material is (AlxCoCrFeMnNi)3O4, wherein the value of x ranges between 0.2 and 1. Raw materials comprise aluminum nitrate, cobalt nitrate, chromium nitrate, ferric nitrate, manganese nitrate and nickel nitrate, wherein the molar ratio of aluminum nitrate to the sum of the rest nitrates is (0.2-1):1. The preparation method comprises the steps of dissolving the nitrates, adding a proper amount of fuel, uniformly mixing, and carrying out low-temperature combustion to obtain the six-element spinel type high-specific-surface-area (AlxCoCrFeMnNi)3O4 high-entropy oxide nano-powder material. The six-element high-specific-surface-area (AlxCoCrFeMnNi)3O4 high-entropy oxide nano-powder prepared according to the method is used as a lithium ion battery negative electrode material, has relatively high specific capacity, excellent cycle characteristic, and is simple in preparation method and low in cost.

The invention discloses a method for preparing ultrafine tungsten copper composite powder by a low-temperature combustion method, which comprises the following steps: using ammonium para-tungstate (APT) or ammonium meta-tungstate (AMT), a copper salt, citric acid and polyethylene glycol as raw materials; mixing the raw materials and adding water to prepare a transparent citric acid sol system; putting the sol system in a spray tower, and obtaining precursor powder by means of spraying and low-temperature combustion; and finally, carrying out reduction on the precursor powder to obtain ultrafine tungsten copper composite powder. The method has the advantages of energy consumption conservation, being simple in process, large in yield ratio, and being suitable for large-scale industrialization production. By using the methods of sol spraying and low-temperature combustion, the speed of crystallization is improved and the phase separation of tungsten and copper is reduced. Particularly, the composite powder is ignited in a reaction kettle to carry out low-temperature combustion, so that the energy can be saved and the subsequent calcining procedure can be canceled through the low-temperature combustion of the composite powder on one hand, and the yield ratio can be improved to a larger extent on the other hand.

The invention discloses a preparation method of a rare-earth-based fluorite type high-entropy oxide powder material and belongs to the field of rare earth oxide powder materials. The method is a low-temperature combustion synthesis method and specifically comprises the following steps: taking rare earth nitride as a metal source and one or a mixture of more of urea, acetic acid, ammonium acetate,oxalic acid and glycine as fuel; and controlling the concentration of metal salt raw materials, types and adding amounts of the fuel, types and adding amounts of a combustion improver and an ignitionmanner to regulate and control properties including granularity, shapes and the like of rare-earth-based fluorite type high-entropy oxide powder. According to the preparation method disclosed by the invention, liquid-phase ingredients are adopted to ensure that a molecular level of the raw materials is uniform and a stoichiometric proportion of a product is realized; meanwhile, the preparation method has the advantages of energy source saving, high production efficiency, greenness and environment protection, no need of complicated post-treatment and the like; and the prepared rare earth oxidepowder has the advantages of high purity, small granularity and uniformity in distribution.

The preparation process of spinel type nanometer composite ferrite material is the organic combination of sol-gel process and low temperature combustion synthesis and is intense oxidation-reduction practically. During forming sol, fuel or oxidant, such as citric acid, is introduced, the sol is dewatered and ignited in air, and oxidant and nitrate react to produce high temperature to promote the formation of spinel type ferrite. The present invention has the demerits of traditional method overcome and obtains spinel type nanometer composite ferrite AFe2o4/SiO2 material directly through combustion in a fast simple process with low power consumption.

The invention relates to a method for preparing a porous nickel-based ODS (Oxide Dispersion Strengthened) alloy, and belongs to the technical field of porous high temperature alloy preparation. The method comprises the following steps of: preparing nano mixed oxide powder by a low temperature combustion synthesis method; then, selectively reducing the oxide powder in hydrogen to obtain ODS alloy powder; then, obtaining a porous blank by pressing, injection moulding and degreasing the powder; and then sintering to obtain the final porous nickel-based ODS alloy or directly performing SPS (Spark Plasma Sintering) to obtain the final porous nickel-based ODS alloy. The method provided by the invention solves the problem that porous nickel-based ODS alloy which is complex in shape is hard to form and the pore structure is hard to control. The method has the advantages of strong designability of porosity and aperture, low cost, high utilization ratio of raw material powder and high strength at a high temperature, and is suitable for high temperature resisting, corrosion resisting and oxidization resisting conditions.

The invention discloses a method for improving low-temperature combustion soot emission and fuel economy of a diesel engine. The method includes the steps of firstly, a control unit reads a rotation speed signal of a sensor mounted on a crankshaft of the engine and an engine load signal of a sensor mounted at an accelerator pedal, and judges operation load and rotation speed of the engine according to the engine load signal and the rotation speed signal; and secondly, a control signal is output according to the judging result obtained in the first step. EGR (exhaust gas recirculation) rate when low-temperature combustion soot emission increases evidently is delayed effectively by the method, EGR tolerance is increased from 35% to above 55%, and soot emission peak is lowered effectively.

The invention discloses a low-temperature combustion catalyst for eliminating diesel engine carbon black, the low-temperature combustion catalyst does not contain alkali metal and precious metal and is ferro-cerium-zirconium composite oxide; wherein the mole percentage composition of CeO2 is 50 percent, the mole percentage composition of Fe2O3 is 5-50 percent, and the mole percentage composition of ZrO2 is 45-0 percent; two preparation methods are included, the method I is coprecipitation hydrothermal synthesis method, the method II is mechanical mixing method; the method I comprises the following steps: Ce, Fe and Zr nitrates are prepared into saline solution with 0.1-0.5mol/L of total concentration according to stoichiometric ratio, and then H2O2 with proper amount is added, the mixture is fully stirred and mixed uniformly; under the strong stirring condition, the mixing solution is dropped in 3-8mol/L of ammonia water at 2-10mL/mim speed, so as to obtain precipitate; after the precipitating is completely carried out, the solution is continuously stirred for 30-120min. after aging is carried out for 30-180min, partial supernatant liquid is removed, the precipitate is transferred to a high pressure reactor (50-70 percent of filling degree) with 160-240 DEG C for 24-72 hours. The obtained product is washed respectively by deionized water and ethanol, and is dried 6-24h at 80-120 DEG C, so as to obtain the target catalyst. The material has high catalytic activity and heat stability, and has no pollution to environment.

The invention discloses a novel preparation method of a Mn-base metal oxide (MnOx) catalyst and application of the MnOx catalyst to the field of volatile organic chemicals (VOCs) low-temperature catalytic combustion. The method comprises the steps that KMnO4 and inorganic liquid acid are dissolved to a certain volume of deionized water to form a solution 1; a certain amount of H2O2 is diluted by deionized water to form a solution 2; on the room temperature condition, the solution 2 is added into the solution 1 dropwise; generated sediment is filtered, washed, dried and roasted at the high temperature after being aged and passing the night, and then the needed MnOx catalyst can be obtained. The method has the advantages that simpleness and quickness are achieved; the problems that the synthetic temperature is high, time is long and the amount of waste water and the number of waste residues are large in a hydrothermal synthesis method and a direct precipitation method can be avoided; a MnOx material of a multilevel structure can be synthesized, and the large comparison area is beneficial for a VOCs catalytic combustion reaction on the surface of the MnOx catalyst. In methylbenzene and methanol low-temperature combustion, the synthesized MnOx has an ideal catalyzing effect.

The low exhaust combustion system for flexible fuel engine includes main gear, rotation speed sensor, two oil pumps with speed regulator, throttle valve position sensor, electric control unit, frequency variator, motor, compressor, pressure stabilizer, scavenging port, exhaust port, oil ejector and cylinder. The present invention consists of engine scavenging and exhausting system and diesel oil and fuel substitute double ejecting system. The present invention has double ejecting system and flexibly selected fuel substitute to lower the exhaust of the engine, two oil pumps for convenient regulation of oil supplying ahead angle and sectional ejecting, homogeneous mixed gas obtained before ignition, fast low temperature combustion, greatly lowered NOx and grain exhaust and raised heat efficiency.

A rotary valve engine using a single rotary valve serving multiple cylinders significantly increases both volumetric and thermodynamic efficiencies. A novel stratified three stage low temperature combustion system reduces both heat transfer loss and combustion process irreversibility. Using large intake and exhaust valves and passages to reduce throttling losses, the rotary valve also contains a combustion valve and passage connected to a central combustion chamber. Combustion is initiated for all cylinders by a fuel injector in this central chamber which then sequentially ignites a second combustion chamber charge located in each cylinder head. A passage in the rotary valve shaft transfers gas from the combustion cycle to the compression cycle varying the compression ratio of the engine, producing EGR, and transferring radical species for combustion to the next cycle. A compounding element on the rotary valve extracts additional thermal energy derived from reduced heat transfer loss and increased energy.

The invention provides a method for exploiting a heavy oil reservoir by strengthening in-situ oil combustion. The method includes: arranging a vertical injection-production well pattern including an injection well and a production well in an exploiting area of the heavy oil reservoir; lighting oil layers by means of chemical ignition or electric ignition; continuously injecting air from the vertical injection well to maintain combustion; continuously exploiting through the production well; injecting 1-3m<3> of hydrogen peroxide slug 30-50% in mass concentration when every 100000-150000Nm<3> of air is injected in the injection well, and alternately injecting in this way; and closely monitoring oxygen content and temperature of gas produced by the production well, and timely adjusting slug injection parameters. Hydrogen peroxide rapidly decomposes at high temperature in the oil layers, so that a large amount of heat and oxygen is provided for oil layer combustion, strengthened combustion is achieved, heavy oil combustion rapidly and favorably crosses a low-heat area to enter a high-temperature combustion area, and continuous oil combustion exploiting is achieved.

The invention relates to double-perovskite tungsten molybdate red fluorescent powder for a white light LED and a preparation method of the double-perovskite tungsten molybdate red fluorescent powder. The chemical expression of the red fluorescent powder is AA<II>1-xLi<+>B<II>O6:xEu<3+>, wherein Eu<3+> is an active ion doped to an A<II> site, and the doping amount x is more than or equal to 0.01 and less than or equal to 0.6; A is any one of or a combination of more of divalent alkaline earth metal ions Ca<2+>, Sr<2+> and Ba<2+>; A<II> is any one of or a combination of more of trivalent rare-earth ions La<3+>, Gd<3+>, Y<3+> and Sc<3+>; B<II> is any one of or a combination of W<6+> and Mo<6+>; and the red fluorescent powder is prepared by adopting a low-temperature combustion method. The double-perovskite tungsten molybdate red fluorescent powder disclosed by the invention can be efficiently excited by near ultraviolet and blue light chips, the luminous efficiency is improved, the preparation process is simple, and the synthesis temperature is low, so that the double-perovskite tungsten molybdate red fluorescent powder is ideal red fluorescent powder suitable for the white light LED.