190 results about "Trichlorohydrin" patented technology

The invention relates to a trichlorosilane three-tower differential pressure coupling energy-saving rectifying and purifying system and an operating method. The trichlorosilane three-tower differential pressure coupling energy-saving rectifying and purifying system comprises a primary tower, a secondary tower and a tertiary tower; the three towers are connected in series from low pressure to highpressure or from high pressure to low pressure, and a condensation re-boiler is arranged between the primary tower and the secondary tower and between the secondary tower and the tertiary tower respectively; and the three towers can be used for light removal, heavy removal and light removal in turn, and also can be used for combining light removal, heavy removal and light removal. According to the characteristics of approach full tower composition and approach temperature in the process of rectifying the trichlorosilane, the invention provides a trichlorosilane differential pressure coupling rectifying process which is expected to greatly reduce the production cost and energy consumption and theoretically rectify and save energy by nearly 70 percent. The technology remarkably improves themarket competitiveness of polycrystal silicon materials and promotes the development of a photovoltaic and information material industry chain.

The invention provides a system for separating and purifying trichlorosilane in production process of polysilicon and an operation method thereof. The system consists of a rectification working section and a recovery refining working section; wherein, the rectification working section comprises six towers, and the recovery refining working section includes three towers; the connection mode of the six towers of the rectification working section is that a lightness-removing tower I, a lightness-removing tower II, a weight-removing tower, a secondary lightness-removing tower, a secondary weight-removing tower I and a secondary weight-removing tower II are sequentially connected with each other; the connection mode of the three towers of the recovery refining working section is that a lower-removing tower, a higher-removing tower and a product refining tower are sequentially connected with each other. Chlorsilane rectification technical equipment can be one of main technical bottlenecks limiting the production of the high-quality polysilicon material in China. The invention can achieve the separation requirements and energy-saving aim under the condition that the mass flow rate elastic ratio between feeding of the rectification working section and feeding of the recovery working section is 1:1-1:5. The rectification technique is simplified and optimized, the separation efficiency is improved, the energy consumption of rectification products is reduced, the reliability and stability of system operation can be enhanced, and the content of phosphorus, arsenic, boron and metallic contamination in the rectification products can be lowered.

The invention provides a polycrystalline silicon producing device, comprising a trichlorosilane synthesis furnace, a trichlorosilane reduction furnace, a silicon tetrachloride hydrogenation furnace, a trichlorosilane synthesis tail gas recycling device and a trichlorosilane reduction tail gas recycling device, wherein the tail gas outlet of the silicon tetrachloride hydrogenation furnace is connected with the feeding hole of the trichlorosilane synthesis furnace, and the air inlet of the trichlorosilane reduction tail gas recycling device is connected with the air outlet of the trichlorosilane reduction furnace. In the invention, the tail gas outlet of the silicon tetrachloride hydrogenation furnace is connected with the feeding hole of the trichlorosilane synthesis furnace, and tail gas produced by silicon tetrachloride hydrogenation directly enters the trichlorosilane synthesis furnace, thus achieving high yield of trichlorosilane and higher purity of polycrystalline product, avoiding discharge of massive impurity of chlorosilane, saving raw material and eliminating a film pressing machine, a liquid chlorine gasification device and a hydrogen chloride synthesis device; meanwhile, the whole production technological process is a material closed-loop circulation formed by silicon tetrachloride hydrogenation and trichlorosilane reduction, and no waste is discharged, thus being beneficial to environmental protection.

The invention discloses a fluidized bed reactor and a method for preparing granular polysilicon and trichlorosilane by employing the same. By utilizing a positive electrode and a negative electrode in the fluidized bed reactor and enabling the current to flow through silicon particles, heat is supplied for the silicon particles in the reactor in a resistance heating manner. By employing the fluidized bed reactor, the purity of the products can be improved, the cost is reduced, industrialized application of large-diameter reactors is allowed, the output is improved, also the inner wall temperature of the reactor is reduced and further silicon deposition is reduced.

The invention discloses a method and a device for removing impurities from a trichlorosilane mixed gas. The method comprises the steps of: carrying out primary spraying on the trichlorosilane mixed gas in a gas and steam mixture humidifying tower by adopting silicon tetrachloride liquid, absorbing metal chloride and siliceous dust by silicon tetrachloride, introducing wet hydrogen in the trichlorosilane mixed gas to obtain SiO2 through reaction, absorbing boron and phosphorus in the trichlorosilane mixed gas through the SiO2; carrying out secondary spraying on the trichlorosilane mixed gas with the silicon tetrachloride liquid in a bubble column, and further removing the metal chloride to obtain a finished product of a trichlorosilane synthesis gas; and connecting the bubble column used for collecting the silicon tetrachloride obtained by spraying the silicon tetrachloride mixed gas for two times to a washing liquid distilling tower, distilling and purifying the silicon tetrachloride with impurities, and circularly spraying by using the silicon tetrachloride. The impurities are removed by adopting a wet method, the impurities in the trichlorosilane mixed gas can be fully removed to obtain high-quality refined trichlorosilane, the silicon tetrachloride can be circularly utilized, and the purposes of saving energy, reducing consumption and decreasing emission are achieved.

The invention relates to a reactive distillation method and equipment for preparing silane through direct disproportionation of trichlorosilane. The reactive distillation method comprises the following steps of: introducing refined trichlorosilane with the purity up to over 9N to a one-step disproportionation reaction distillation tower to prepare the silane; extracting a reaction product from the top of the disproportionation reaction distillation tower in a gas phase way, entering a silane tower by utilizing differential pressure, obtaining a chlorosilane mixture at the bottom of the tower, and entering a silicon tetrachloride tower; obtaining a high-purity liquid-phase silane product at the top of the silane tower, obtaining unreacted chlorosilane at the bottom of the tower, and returning the unreacted chlorosilane to the disproportionation reaction distillation tower; and obtaining unreacted chlorosilane at the top of the silicon tetrachloride tower, returning the unreacted chlorosilane to the disproportionation reaction distillation tower, and obtaining a silicon tetrachloride product at the bottom of the tower. Light and heavy impurities in the refined trichlorosilane raw material with the purity lower than 9N are removed after the trichlorosilane passes through a partition plate rectification tower so as to obtain trichlorosilane with the purity up to over 9N. The one-step disproportionation reaction is realized in one reaction distillation tower, the equipment is simplified, meanwhile, a great number of circular reactions for material separation are avoided, the processes are shortened, the energy is saved, and the consumption is reduced. The purity of a silane product is higher.

The invention discloses a catalyst and a preparation method thereof. The method comprises: contacting a soluble nickel salt, a soluble salt compound of metal M, a silicon source able to provide silica with a precipitant able to precipitate nickel and/or metal M ions in a solvent, filtering the contact product, and drying and roasting the obtained solid in order, wherein the M is selected from one or more of I B, II B, II A and group VIII metals except Ni. The catalyst prepared according to the method provided by the invention can be applied in preparation of trichlorosilane by hydrogenation of silicon tetrachloride. Compared with conventional aluminum-based catalysts, the catalyst prepared by the method provided by the invention has the advantages that: in the reaction atmosphere of preparation of trichlorosilane by hydrogenation of silicon tetrachloride, the SiO2 carrier is stable, the catalyst skeleton is not easily damaged as the carriers in traditional hydrogenation catalysts, therefore the service life can be longer, and compared with nickel salt and copper salt catalysts commonly used in the prior art, the activity is enhanced.

The invention discloses a polycrystalline silicon production method and polycrystalline silicon production equipment based on improved Siemens method, and belongs to the technical field of polycrystalline silicon production. The problems that the purity of trichlorosilane participating in a reduction reaction is low and first-time conversion rate of trichlorosilane is influenced to cause high production cost of the polycrystalline silicon are solved. According to the technical scheme, the polycrystalline silicon production method comprises the following steps: step 1, performing reduction and deposition on trichlorosilane to acquire polycrystalline silicon and exhausting tail gas; step 2, performing multilevel condensation on the tail gas to acquire non-condensable gas and condensate liquid, introducing the non-condensable gas into an absorption tower, absorbing HCL in the non-condensable gas and enabling a chlorosilane pregnant solution to flow out; after mixing the condensate liquid with the chlorosilane pregnant solution, enabling the condensate liquid to flow into an analyzing tower; step 3, performing a disproportionation reaction on at least a portion of chlorosilane barren liquid flowing out of the analyzing tower, so that the mass percentage content of dichlorosilane in the chlorosilane barren liquid is reduced; step 4, enabling the chlorosilane barren liquid after reaction to flow into a rectifying tower and pouring a product acquired in the rectifying tower into a reduction furnace.

The invention provides a method for preparing silicon tetrachloride for optical fiber. The method comprises the following steps of: introducing chloride under the protective atmosphere of inactive gas or inert gas and under the condition of illumination, so that trichlorosilane is subjected to a photochemical reaction in a rectifying tower, wherein high-boiling-point silicon tetrachloride generated in the production process of polycrystalline silicon serves as a raw material; and controlling the tower kettle temperature and the tower top temperature and taking materials by selecting proper reflux ratio to obtain an intermediate product; further rectifying and purifying the intermediate product to obtain high-purity silicon tetrachloride, wherein infrared transmissivity of hydrogen-containing impurities meets the requirement of the silicon tetrachloride for the optical fiber on impurity transmissivity; and the metal ion content meets the metal content standard of the silicon tetrachloride for the optical fiber. The method has the advantages that: the trichlorosilane with the boiling point close to that of the silicon tetrachloride is removed effectively; the hydrogen-containing impurity content and the metal impurity content of the silicon tetrachloride are reduced; the quality of the silicon tetrachloride purified and prepared by the process completely meets the requirement of optical fiber products; the reaction condition and the completeness are easy to control; other impurities are not introduced; and the method is implemented in an industrial scale and in an effective and economic mode.

The invention relates to a method for producing trichlorosilane and equipment thereof, in particular to a processing method of dust generated in the producing process of trichlorosilane and equipment thereof. The mixture of the tail gas and the dust in the producing process of the trichlorosilane is processed through a filtering device, the intercepted dust is then processed through a bag filter in two steps, at least one cloth-bag blowing pipe for blowing out nitrogen is arranged in the bag filter for processing the dust, and the cloth-bag blowing pipe comprises a main pipe, a branch pipe and at least one nozzle, wherein the main pipe is arranged at the bottom or the top of the filter, a branch pipe is installed on the main pipe and is parallel between filtering bags and the nozzle is arranged on the branch pipe; and at least one dust blowing pipe is arranged at the dust inlet of the bag filter, the dust blowing pipe is used for blowing out the nitrogen, and the dust is deposited at the bottom of the bag filter after being blown dispersedly. The processing method of the tail gas and the dust of the invention can realize continuous operation, saves the usage amount of the nitrogen, reduces the discharge of pollutants, and can be used for producing byproducts containing ammonium chloride.

The invention relates to a polycrystalline silicon production process, in particular to a trichlorosilane vaporizing process, belonging to the technical filed of production of polycrystalline silicon. The trichlorosilane vaporizing process comprises the following steps of: (1) rectifying to obtain high-purity trichlorosilane liquid, metering and feeding into an evaporator for evaporating; and (2)mixing the trichlorosilane gas obtained through evaporation with metered hydrogen in a gas mixer to obtain a mixed gas. In the trichlorosilane vaporizing process, the trichlorosilane gas is mixed with the hydrogen, so that the uniformly mixed gas with a stable mixture ratio can be obtained; and raw materials are mixed more uniformly, uniform growth of polycrystalline silicon rods in a reduction furnace is promoted, and grown polycrystalline silicon products have uniform crystal grains and better appearance quality.

The invention discloses a waste residue comprehensive utilization method for a trichlorosilane leaching system. The waste residue comprehensive utilization method comprises the following steps: filter pressing a leaching waste residue mixed solution formed by the leaching system by using a filter press to obtain leaching waste residue; putting the leaching waste residue into a drum mixer, adding an appropriate amount of tap water, and stirring to obtain a slurry; discharging the slurry to a dissolving tank by utilizing a high potential difference, adding the appropriate amount of the tap water, mechanically stirring to dissolve for 1.5-4 hours, and obtaining a feed liquid containing sodium chloride; filter pressing the feed liquid to obtain insoluble residue and filtrate, storing the insoluble residue for later use, performing secondary refined filtration on the obtained filtrate, injecting a refined filtration mother liquid into a double-effect evaporator through a centrifugal pump to evaporate and crystallize, and obtaining a finished product, sodium chloride with the purity of more than 99%. According to the waste residue comprehensive utilization method for the trichlorosilane leaching system, soluble salt and insoluble salt are effectively separated, and a purpose of recycling leaching waste residue in a classifying manner is achieved; the environment pollution and the wasting of resources are reduced, and the economic benefits are increased.

The present invention discloses a new vinyl alkoxy silane preparation process, which is characterized in that hydrogen chloride produced during a preparation process is adopted as a reactant to synthesize an initial raw material trichlorosilane, the hydrogen chloride is recycled, and the byproduct bis(trialkoxy)silyl ethane is adopted as a reaction solvent during a hydrogen silicon addition process, such that the byproduct emission is reduced, the new impurity introduction is avoided, and the product purity is improved. According to the present invention, the new process has characteristics of stable production, simple preparation process, and mild reaction conditions, and the yield of the product vinyl alkoxy silane is high, and the product purity is more than 99%.

The invention discloses a method for intermittently recycling chlorosilane in discharged waste liquid in a washing tower during polycrystalline silicon production, and the method the following steps of: intermittently charging a chlorosilane waste liquid produced in polycrystalline silicon production into an evaporation device at different places, evaporating trichlorosilane and silicon tetrachloride with lower boiling point into a gas state when the temperature of the evaporation device is controlled at 120-180DEG C and the pressure of the evaporation device is controlled at 0.1-0.6MPa, and charging the gaseous trichlorosilane and silicon tetrachloride into a rectifying tower so as to be purified and recycled. The invention further provides the evaporation device used in the method. The invention has the beneficial effects that the method is simple in process, the process condition is easy to realize, and the method is convenient to operate; and the treatment difficulty of the chlorosilane waste liquid during polycrystalline silicon production in the process of production can be improved, the discharge quantity of exhaust liquor can be mainly reduced, the waste of the chlorosilane can be reduced, the treatment load of an alkali liquor pond can be reduced, the environment pollution problem can be remitted, the labor quantity can be reduced, the production cost can be reduced, the complete recycle of the chlorosilane can be realized, and the phenomenon of equipment blockage can be avoided.

The invention relates to an anhydrous treatment process for polycrystalline silicon slurry. The process comprises the following steps of (1) carrying out solid-liquid-gas separation on upstream polycrystalline silicon slurry to obtain a liquid, gas A and a solid A, treating the liquid and the gas A, and collecting to obtain a liquid A; (2) heating and stirring the solid A by steam to obtain a dried solid product and silicon tetrachloride and part of trichlorosilane which exist in a gas manner, treating the silicon tetrachloride and part of trichlorosilane existing in a gas form, and collectingto obtain a liquid B; (3) heating the dried solid product through a pyrolyzing furnace to obtain solid wastes and high-boiling residues in a gaseous form, and carrying out catalytic cracking on the high-boiling residues in the gaseous form to obtain gas B and a liquid C; (4) allowing the solid wastes to pass through a gas locking tank, a cooling screw and a solid bin in sequence and discharging the solid wastes to a packaging and delivery unit, and (5) separating the liquid A, the liquid B, the liquid C and the gas B to obtain silicon tetrachloride and trichlorosilane products, residual high-boiling residues and part of solid B. The process has high utilization efficiency, and the anhydration is realized.

The invention discloses a synthetic method and apparatus for trichlorosilane. According to the method, silicon powder with a particle size in a range of 200 to 400 meshes is used for reaction with hydrogen chloride so as to synthesize trichlorosilane; the used silicon powder has a wide particle size range and is low in production cost and reduced in the difficulty coefficient of production; and since the silicon powder in a wide particle size range has low fluidizing gas velocity, the mole fraction of corresponding introduced hydrogen chloride can be reduced during preparation of trichlorosilane, so difficulty of and cost for tail gas recovery is lowered. Compared with silicon powder used in preparation of trichlorosilane in the prior art, the silicon powder in a particle size range of 200 to 400 meshes in the invention has a greater specific surface area, so a gas-solid contact area is increased and reaction intensity is improved; and thus, the production power of the synthetic method and apparatus for trichlorosilane in the invention is improved.

The invention discloses a separation device and separation method for removing silicon tetrachloride in an organosilicon monomer azeotrope, the separation device comprises: a first separation tower for separating the organosilicon monomer azeotrope, a fixed bed reactor connected with the tower top of the first separation tower, wherein a tower top material of the first separation tower flows intothe fixed bed reactor and undergoes a reverse disproportionation reaction with a dichlorosilane product under the catalytic action of a catalyst to generate trichlorosilane, a second separation towerconnected with the fixed bed reactor and used for separating materials flowing out of the fixed bed reactor, wherein a trimethyl monochlorosilane product is obtained at the tower bottom of the secondseparation tower, and a dichlorosilane product is obtained at the tower top of the second separation tower. According to the method disclosed by the invention, the load of a rectifying device in the prior art can be greatly reduced, silicon tetrachloride azeotrope in the organic silicon monomer azeotrope is removed, and silicon tetrachloride is converted into trichlorosilane.

The invention relates to a preparation method of alkoxy silane. According to the method, silicon waste is used as a raw material, the raw material comprises a rectified liquid high-boiling residue anda byproduct silica powder, and the rectified liquid high-boiling residue is mainly composed of trichlorosilane, silicon tetrachloride and high polymers thereof; when the rectified liquid high-boilingresidue is used as a raw material, anhydrous alkoxy alcohol and the rectified liquid high-boiling residue are directly added into a reactor to react; when the byproduct silica powder is used as a rawmaterial, a novel composite catalyst system is formed by adopting a copper-based catalyst and an auxiliary agent, the silica powder and the composite catalyst are pretreated, a mixture and anhydrousalkoxy alcohol are uniformly dispersed in a suspending agent, and a direct synthesis reaction is carried out in the reactor. According to the method, the utilization way of the silicon waste is widened, and high-added-value utilization of the silicon waste is achieved; in addition, the use amount of alkoxy alcohol is also reduced, the conversion rate of the silicon waste is improved, and the purity and yield of the product are improved.

The invention relates to a device and method for producing silane by disproportionated reaction distillation of trichlorosilane. The device is a distillation tower; the distillation tower is provided with a distillation section, a reaction section and a stripping section; a tower-top deep freezer is arranged on the distillation section; a tower kettle is provided with a reboiler; the distillation section and the stripping section are internally provided with structured packing; the reaction section is internally provided with a structure catalyst; a tower-top condenser and the distillation section are respectively provided with a vacuum jacket and an insulating layer; the vacuum jackets of the tower-top condenser and the distillation section are respectively provided with a vacuum extraction opening; the reaction section and the stripping section are provided with insulating layers; a silane outlet is arranged at the tower top; the tower-top deep freezer is provided with a tower-top condensate inlet and a tower-top condensate outlet; and a trichlorosilane inlet is arranged under the reaction section. Compared with a multi-step disproportionation process, the process has the advantages that the equipment is simple, the multi-step disproportionation reaction can be realized only by one reaction distillation tower, silicon tetrachloride as a product of the tower kettle returns into a cold hydrogenation system and is converted into the trichlorosilane, so that the closed-loop circulation is realized and simultaneously the purity of the obtained silane is high.