Process for preparing pure sulfur trioxide through three-section conversion of pure oxygen by using double sulfur burning furnaces

Abstract

The invention provides a technology for preparing pure sulfur trioxide through three-section conversion of pure oxygen by using double sulfur burning furnaces, and relates to the technical field of sulfur trioxide production, and the technology comprises the following steps: step 1, sulfur burning reaction, step 2, heat recovery, and step 3, condensation separation. The double sulfur burning furnaces are arranged to burn sulfur, the total rated sulfur spraying amount is kept, meanwhile, the burning temperature of a single sulfur burning furnace is reduced to a certain extent, a high-temperature and high-oxygen environment is prevented from being generated in the furnaces, the product yield is guaranteed, meanwhile, related equipment of the sulfur burning furnaces is protected, and the production cost is reduced. The invention also discloses a preparation method of the composite carrier loaded vanadium tungsten molybdenum pentoxide catalyst used in the production process.

Description

Technical Field

[0001] The invention relates to the technical field of sulfur trioxide production, and in particular to a process for preparing pure sulfur trioxide by converting pure oxygen into pure sulfur trioxide in three stages using a double sulfur incinerator. Background Art

[0002] Sulfur trioxide is a sulfur oxide with a similar smell to sulfur dioxide. It dissolves in water and reacts to form sulfuric acid. Its gaseous form is a serious pollutant and one of the main sources of acid rain. Existing pure sulfur trioxide products are mainly produced by the oleum method, which relies on traditional sulfur / pyrite acid production equipment to absorb sulfur trioxide gas with sulfuric acid to produce oleum, and then distill sulfur trioxide gas to obtain sulfur trioxide gas. The gas is cooled and liquefied to obtain a liquid pure sulfur trioxide product.

[0003] In order to improve the economy and efficiency of exhaust gas treatment, the dust removal and catalytic processes are combined together. The catalyst needs to face the high temperature corrosion environment. Although a single metal catalyst has good catalytic performance, its surface area is poor and it cannot contact more flue gas, resulting in too low efficiency. Using a single substrate has poor mechanical strength and stability, and the catalyst is prone to failure. Therefore, a preparation method of a composite carrier-loaded vanadium pentoxide tungsten-molybdenum catalyst is developed to solve the above problems.

[0004] In addition, in the traditional sulfuric acid production process, most of the sulfur trioxide generated by catalytic oxidation in the conversion section is combined with the desalted water added to the dry absorption system and converted into sulfuric acid and fuming sulfuric acid products. The output of pure sulfur trioxide products is difficult to increase and the yield of finished products is extremely low. Secondly, the traditional process only has one sulfur incinerator, which is prone to generate high temperatures, causing damage or destruction to the sulfur incinerator. Summary of the invention

[0005] The present invention provides a process for preparing pure sulfur trioxide by converting pure oxygen in three stages using a double sulfur incinerator, so as to solve the problems raised in the above background technology.

[0006] In order to solve the above technical problems, the present invention discloses a process for preparing pure sulfur trioxide by converting pure oxygen in three stages using a double sulfur incinerator, comprising the following steps:

[0007] Step 1 is the sulfur incineration reaction process: liquid sulfur and pure oxygen are sent to the primary sulfur incinerator and the secondary sulfur incinerator for combustion to generate sulfur dioxide. Then, sulfur dioxide is converted into sulfur trioxide through a three-stage converter, and a composite carrier-supported vanadium tungsten-molybdenum pentoxide catalyst is used in the process; Step 2 is the heat recovery process: the chemical heat energy generated in step 1 is collected; Step 3 is the condensation separation process: the generated sulfur trioxide is collected as a finished product, and the mechanical heat energy generated is also recovered through heat recovery.

[0008] Furthermore, the sulfur burning reaction process includes a primary sulfur burning furnace, a secondary sulfur burning furnace and a three-stage converter. The three-stage converter includes a first stage converter, a second stage converter and a third stage converter. Liquid sulfur and one of the pure oxygen are introduced into the primary sulfur burning furnace and the second stage sulfur burning furnace to start combustion. The gas generated by the combustion of the primary sulfur burning furnace is introduced into the second stage sulfur burning furnace. The gas generated by the combustion of the primary sulfur burning furnace is mixed with the liquid sulfur and pure oxygen that enter the second stage sulfur burning furnace separately and burns. The gas after combustion passes through the first stage converter, the second stage converter and the third stage converter in sequence.

[0009] Furthermore, the heat recovery process includes a primary combustion heat recovery device, a secondary combustion heat recovery device, a high-temperature heat recovery device, a medium-temperature heat recovery device, a low-temperature heat recovery device, and an economizer; the gas generated by the combustion of the primary sulfur incinerator enters the primary combustion heat recovery device for cooling, and then the gas is passed into the secondary sulfur incinerator; the gas generated by the combustion of the secondary sulfur incinerator enters the secondary combustion heat recovery device for cooling; the gas cooled by the secondary combustion heat recovery device is mixed with another stream of pure oxygen and enters the first stage of the converter, the temperature of the gas is increased after the first stage of catalytic oxidation, the first stage outlet gas enters the high-temperature heat recovery device for heat exchange, and then enters the second stage of the converter; the temperature of the gas after the second stage of catalytic oxidation is increased again, the second stage outlet gas enters the medium-temperature heat recovery device for heat exchange again, and enters the third stage of the converter for reaction; the gas exiting the third stage of the converter enters the low-temperature heat recovery device and the economizer in turn.

[0010] Furthermore, the condensation separation process includes a heat exchanger, a compressor, and a heat recovery condensing device; the gas at the economizer outlet enters the heat exchanger for heat exchange, the thermal energy in the gas is fully utilized, and the temperature of the gas is greatly reduced; then the gas enters the compressor, and the mechanical energy is converted into the internal energy of the gas by the work of the compressor, the gas volume is reduced, the gas pressure is increased, and the temperature is increased again; the heated gas enters the heat recovery condensing device to recover the mechanical heat energy of the compressor and condense the finished pure sulfur trioxide before being produced.

[0011] Furthermore, a portion of the gaseous sulfur trioxide in the gas is separated in the heat recovery condensing device as pure sulfur trioxide product for production, and the remaining uncondensed gas components are used as non-condensable gas and connected to the primary sulfur incinerator and the secondary sulfur incinerator through the gas phase outlet of the heat recovery condensing device to participate in the next cycle of the production process; an exhaust gas discharge process is added on the way from the gas phase outlet pipeline of the heat recovery condensing device to the primary sulfur incinerator and the secondary sulfur incinerator, and a small portion of the non-condensable gas is treated by the exhaust gas absorption system.

[0012] Furthermore, the preparation method of the composite carrier-supported vanadium pentoxide-tungsten-molybdenum catalyst comprises the following steps:

[0013] Step 1: Mixed particle preparation: diatomaceous earth, ball milling medium and alumina particles are mixed by a particle preparation device, a wetting agent is added, and then ball milling, grinding and drying are performed to obtain mixed particles;

[0014] Step 2: dissolving the precursor of vanadium pentoxide and the precursor of tungsten in N,N-dimethylformamide solution, adding nano sodium molybdate and mixed particles, and stirring after ultrasonic dispersion to obtain a spinning solution;

[0015] Step 3, electrospinning the spinning solution obtained in step 2 to obtain a fiber membrane, placing it on quartz after drying, placing it in a tubular heating furnace, heating it under a nitrogen atmosphere, introducing hydrogen to react, heating it to introduce acetylene to react, cooling it under a nitrogen atmosphere, and obtaining vanadium pentoxide tungsten molybdenum-carbon nanotubes;

[0016] Step 4: blending the vanadium pentoxide tungsten molybdenum-carbon nanotubes obtained in step 3 with polytetrafluoroethylene fibers and aluminum silicate fibers to obtain a product.

[0017] Furthermore, in the preparation method of the composite carrier-supported vanadium pentoxide-tungsten-molybdenum catalyst, the precursor of vanadium pentoxide in step 1 is aminovanadate;

[0018] Preferably, the tungsten precursor is one or both of tungsten hexacarbonyl and tungsten hexaisopropoxide;

[0019] Preferably, the ball milling medium is corundum ball, and the wetting agent is polydimethylpolysiloxane.

[0020] Furthermore, in the preparation method of the composite carrier-supported vanadium pentoxide tungsten-molybdenum catalyst, the weight ratio of the diatomaceous earth, the ball milling medium and the alumina particles in step 1 is 1:7:3;

[0021] Preferably, the weight ratio of the nano sodium molybdate and the mixed particles added in step 2 is:.

[0022] Furthermore, in step 3 of the preparation method of the composite carrier-supported vanadium pentoxide tungsten-molybdenum catalyst, the electrospinning voltage is 10-20 kV, the spinning solution flow rate is 0.1-1 mm / min, and the calcination temperature is 600-900° C.;

[0023] Preferably, in step 3, the flow rate of hydrogen introduced is 200 ml / min, and the flow rate of acetylene introduced is 50 ml / min.

[0024] Furthermore, in step 4 of the method for preparing the composite carrier-loaded vanadium pentoxide tungsten-molybdenum catalyst, the mass ratio of the vanadium pentoxide tungsten-molybdenum-carbon nanotubes to the PTFE fibers and the aluminum silicate fibers is: :.

[0025] Preferably, the particle preparation device comprises: a preparation shell and a conical heating element, a conical heating element is fixedly provided at the bottom of the preparation shell, a supporting foot is installed at the bottom of the conical heating element, a transmission chamber 1, a guide chamber, a transmission chamber 2, a grinding chamber and a transmission chamber 3 are provided in the preparation shell, a crankshaft assembly 1 is installed in the transmission chamber 2, and one end of the crankshaft assembly 1 is movably extended into the transmission chamber 1, and the other end of the crankshaft assembly 1 is fixedly connected to the top of the drive shaft, and one end of the two sets of crankshaft assemblies 1 extending into the transmission chamber 1 are fixedly sleeved with a pulley 1, and the two sets of pulleys 1 are connected for transmission through a belt 1, and the guide block is connected to the first connecting rod through the first connecting rod. The crankshaft assembly is hinged, the fixed part slides up and down in the guide cavity, and one end of the second connecting rod is hinged to the first connecting rod, and the other end of the second connecting rod is hinged to the fixed part. The grinding head and the rotating grinding sleeve are both installed in the grinding cavity, and the grinding head and the rotating grinding sleeve are provided with the same grinding teeth on the side close to each other. The grinding head is connected to the fixed part through the second connecting rod, the rotating grinding sleeve is movably connected to the inner wall of the grinding cavity, and the outer wall of the rotating grinding sleeve is fixedly sleeved with gear 2, gear 1 is fixedly sleeved on the outer wall of the drive shaft, and gear 1 and gear 2 are meshed. A filter is installed at the connection between the bottom of the grinding cavity and the feed channel, and an annular The rolling piece is rotatably connected to the inner wall of the feeding channel through a rotating shaft, and the bottom of the rotating shaft on one side extends into the transmission chamber three, the second pulley is fixedly sleeved on the outer wall of the driving shaft, the third pulley is fixedly sleeved on the outer wall of the rotating shaft extending into the transmission chamber three, the second pulley and the third pulley are connected through the second belt transmission, the driving motor one is installed in the preparation shell, and the output shaft of the driving motor one is fixedly connected to the bottom of the driving shaft, the outer wall of the preparation shell is provided with a feeding bin, and the feeding bin is connected with the grinding chamber through the feeding channel, the shell of the conical heating element is embedded with a heating wire, and the top of the conical heating element is provided with a feeding port connected with the feeding channel Material inlet, the circulating material barrel is fixedly connected to the inner wall of the conical heating element through a fixed rod, the bottom of the circulating material barrel is fixedly connected to the inner wall of the conical heating element through a support ring, the pushing block is movably arranged in the conical heating element, the circulating material barrel is a structure with upper and lower openings, and the diameter of the pushing block is smaller than the inner diameter of the circulating material barrel, the motor fixing plate is fixedly connected to the supporting foot, and a driving motor 2 is installed on the motor fixing plate, the output end of the driving motor 2 is fixedly connected to the bottom of the third connecting rod through the crankshaft assembly 2, the top of the third connecting rod movably extends into the conical heating element and is fixedly connected to the pushing block, and the outer wall of the conical heating element is provided with a discharge port, and a solenoid valve is installed on the discharge port.

[0026] Compared with the prior art, the present invention provides a process for preparing pure sulfur trioxide by converting pure oxygen in three stages in a double sulfur incinerator, which has the following beneficial effects:

[0027] 1. Using pure oxygen and liquid sulfur as raw materials, the finished sulfur trioxide is produced continuously without any by-products. The finished product yield is close to 100% and the product quality is pure.

[0028] 2. Setting up double sulfur incinerators to burn sulfur can maintain the total rated sulfur injection volume while reducing the combustion temperature of a single sulfur incinerator to a certain extent, avoiding the generation of a high-temperature and high-oxygen environment in the furnace. While ensuring product output, it can further protect the sulfur incinerator-related equipment and extend the life of the device.

[0029] 3. Establish a relatively closed flue gas circulation system. Theoretically, the device does not produce three wastes. The tail gas treatment system is only set up to balance the pressure fluctuations in actual production.

[0030] 4. Different from the traditional sulfuric acid production, there is no heat energy consumption caused by flue gas heat exchange in the device, so the combustion heat, conversion heat, etc. can be used to increase steam production, further reducing the unit consumption of steam output.

[0031] 5. There is no water in the system to participate in the reaction, and no acid mist or condensed acid will be formed, which greatly reduces the damage to the catalyst in the converter and the internal masonry of the equipment, prolongs the life of the catalyst and reduces the damage caused by corrosion to the equipment;

[0032] 6. Diatomaceous earth has a porous structure, which can effectively increase the specific surface area of ​​the catalyst, promote the diffusion and contact of reactants, and improve the catalytic efficiency. Alumina can withstand high temperature environments and usually maintains stable chemical properties under conditions above 1000°C, which makes up for the slightly insufficient performance of diatomaceous earth at high temperatures. Polydimethylpolysiloxane (PDMS) has good chemical stability and elasticity, which can improve the corrosion resistance of the catalyst and its ability to withstand gas pulsation in chemical production processes, and maintain long-term stable operation of the system;

[0033] 7. Vanadium pentoxide and tungsten and molybdenum metal catalysts can effectively promote the catalytic reduction reaction of sulfur trioxide, and the carbon nanotubes generated by the metal catalyst are conducive to making the catalytic reaction contact area wider, enhancing the dispersibility of the active metal in the catalyst, increasing the density of its surface active sites, promoting the catalytic reaction, and forming a more efficient catalytic reaction interface. PTFE has excellent corrosion resistance and can resist the erosion of various acids, alkalis and organic solvents. This prolongs the stability and life of the catalyst in harsh environments. The high surface energy of PTFE and its wettability at the nano level further help to improve its contact with the reactants. Aluminum silicate, as a structural material, can improve the mechanical strength and impact resistance of the catalyst, prevent it from breaking or deforming under high temperature and airflow impact, thereby ensuring the effectiveness and durability of the catalyst. The porous medium formed by the PTFE-aluminum silicate fiber structure helps to optimize gas flow, increase the diffusion rate of gas in the catalyst, and thus improve the reaction rate and efficiency. It has good filtering performance and can effectively capture dust and particulate matter in the gas. The vanadium pentoxide generated by the thermal decomposition of aminovanadate at 600 degrees has high purity;

[0034] 8. The various formulas work synergistically to make up for the deficiencies of a single raw material. By improving corrosion resistance, increasing mechanical strength, improving reaction conditions and filtering performance, the overall performance of the catalyst is significantly improved, ensuring its effectiveness and reliability in dust removal and catalytic applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0036] Figure 1 is a process flow chart of the present invention;

[0037] Figure 2 It is a structural schematic diagram of the tail gas absorption system of the present invention;

[0038] Figure 3 It is a schematic diagram of the structure of the particle preparation device in the present invention;

[0039] Figure 4 This is a schematic diagram of the cross-sectional structure of the shell prepared in the present invention;

[0040] Figure 5 It is a schematic diagram of the cross-sectional structure of the conical heating element in the present invention.

[0041] In the figure: 1. liquid sulfur; 2. pure oxygen; 3. primary sulfur incinerator; 4. primary combustion heat recovery device; 5. secondary sulfur incinerator; 6. secondary combustion heat recovery device; 7. converter section 1; 8. high temperature heat recovery device; 9. converter section 2; 10. medium temperature heat recovery device; 11. converter section 3; 12. high temperature heat recovery device; 13. economizer; 14. heat exchanger; 15. compressor; 16. heat recovery condensation device; 17. tail gas absorption system; 18. finished pure sulfur trioxide; 19. shell preparation; 20. transmission chamber 1; 21. guide chamber; 22. belt 1; 23. transmission chamber 2; 24. pulley 1; 25. first connecting rod; 26. guide block; 27. second connecting rod; 28. second connecting rod; 29. ​​fixing piece; 30 , drive shaft; 31, crankshaft assembly one; 32, feeding bin; 33, grinding chamber; 34, feeding channel; 35, feeding port; 36, supporting foot; 37, grinding head; 38, grinding teeth; 39, rotating grinding sleeve; 40, gear one; 41, gear two; 42, filter screen; 43, rotating shaft; 44, annular rolling part; 45, pulley two; 46, transmission chamber three; 47, driving motor one; 48, belt two; 49, pulley three; 50, feeding channel; 51, conical heating element; 52, heating wire; 53, circulating barrel; 54, fixing rod; 55, supporting ring; 56, pushing block; 57, third connecting rod; 58, motor fixing plate; 59, driving motor two; 60, crankshaft assembly two; 61, feeding port. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0043] In addition, in the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes, and do not specifically refer to the order or sequence, nor are they used to limit the present invention. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions and technical features between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0044] Unless otherwise specified, the examples and comparative examples are parallel tests with the same components, component contents, preparation steps and preparation parameters. The experimental methods in the following examples are conventional methods unless otherwise specified. The experimental materials used in the following examples are analytical reagents (AR) unless otherwise specified, which are purchased from commercial channels.

[0045] The diatomaceous earth is white diatomaceous earth of 4000 mesh, purchased from Shanghai Yuanjiang Chemical Co., Ltd.; the alumina particles have a particle size of 5 mm and a purity of 98%, purchased from Beijing Beike New Materials Technology Co., Ltd.; the nano sodium molybdate has a molybdenum content of ≥99.90% and a particle size of 30 nm, purchased from Hubei Sino-Australian Nanomaterials Technology Co., Ltd.; the PTFE fiber is SABIC LNP.

[0046] Example 1

[0047] like Figure 1-2 As shown, the process comprises the following steps: step 1, a sulfur incineration reaction process, wherein liquid sulfur 1 and one of the streams of pure oxygen 2 are introduced into a primary sulfur incinerator 3 and a secondary sulfur incinerator 5 to burn to generate sulfur dioxide, and then the sulfur dioxide is converted into sulfur trioxide through a three-stage converter, and the composite carrier loaded with vanadium pentoxide tungsten-molybdenum catalyst is placed in the sulfur incinerator and the converter; step 2, a heat recovery process, wherein the chemical heat energy and mechanical heat energy generated in step 1 are recovered; and step 3, a condensation process, wherein the sulfur trioxide generated in step 1 is condensed and separated, and is extracted as a finished pure sulfur trioxide 18.

[0048] The working principle and beneficial effects of the above technical solution are as follows: the first step is a sulfur incineration reaction process, in which liquid sulfur 1 and one of the pure oxygen 2 are introduced into a primary sulfur incinerator 3 and a secondary sulfur incinerator 5 to burn to produce sulfur dioxide, and then the sulfur dioxide is converted into sulfur trioxide through a three-stage converter; the second step is a heat recovery process, in which the chemical heat energy and mechanical heat energy generated in step one are recovered; the third step is a condensation process, which is used to condense and separate the sulfur trioxide generated in step one and produce it as a finished pure sulfur trioxide 18.

[0049] 1. Using pure oxygen 2 and liquid sulfur 1 as raw materials, the finished product pure sulfur trioxide 18 is continuously produced without any by-products. The finished product yield is close to 100% and the product quality is pure.

[0050] 2. Setting up double sulfur incinerators to burn sulfur can maintain the total rated sulfur injection volume while reducing the combustion temperature of a single sulfur incinerator to a certain extent, avoiding the generation of a high-temperature and high-oxygen environment in the furnace. While ensuring product output, it can further protect the sulfur incinerator-related equipment and extend the life of the device.

[0051] Example 2

[0052] On the basis of the above-mentioned embodiment 1, Figure 1-2 As shown, the sulfur burning reaction process includes a primary sulfur burning furnace 3, a secondary sulfur burning furnace 5 and a three-stage converter, the three-stage converter includes a first stage converter 7, a second stage converter 9 and a third stage converter 11, liquid sulfur 1 and one of the pure oxygen 2 are introduced into the primary sulfur burning furnace 3 and the secondary sulfur burning furnace 5 to start combustion, the gas generated by the combustion of the primary sulfur burning furnace 3 is introduced into the secondary sulfur burning furnace 5, the gas generated by the combustion of the primary sulfur burning furnace 3 is mixed with the liquid sulfur and pure oxygen separately entering the secondary sulfur burning furnace 5 and burned, and the gas after combustion passes through the first stage converter 7, the second stage converter 9 and the third stage converter 11 in sequence.

[0053] Among them, preferably, the heat recovery process includes a primary combustion heat recovery device 4, a secondary combustion heat recovery device 6, a high-temperature heat recovery device 8, a medium-temperature heat recovery device 10, a low-temperature heat recovery device 12, and an economizer 13; the gas generated by the combustion of the primary sulfur incinerator 3 enters the primary combustion heat recovery device 4 for cooling, and then the gas is passed into the secondary sulfur incinerator 5; the gas generated by the combustion of the secondary sulfur incinerator 5 enters the secondary combustion heat recovery device 6 for cooling; the gas cooled by the secondary combustion heat recovery device 6 is mixed with another stream of pure oxygen 2 and enters the first stage of the converter 7, the gas temperature is increased after the first stage of catalytic oxidation, the first stage outlet gas enters the high-temperature heat recovery device 8 for heat exchange, and then enters the second stage of the converter 9; the gas temperature after the second stage of catalytic oxidation is increased again, the second stage outlet gas enters the medium-temperature heat recovery device 10 for heat exchange again, and enters the third stage of the converter 11 for reaction; the gas out of the third stage of the converter 11 enters the low-temperature heat recovery device 12 and the economizer 13 in turn.

[0054] Among them, preferably, the condensation process includes a heat exchanger 14, a compressor 15, and a heat recovery condensing device 16; the gas at the outlet of the economizer 13 enters the heat exchanger 14 for heat exchange, the thermal energy in the gas is fully utilized, and the temperature of the gas is greatly reduced; then the gas enters the compressor 15, and the compressor 15 does work, the mechanical energy is converted into the internal energy of the gas, the gas volume is reduced, the gas pressure is increased, and the temperature is increased again; the heated gas enters the heat recovery condensing device 16 to recover the mechanical heat energy of the compressor and condense the finished pure sulfur trioxide 18 before being produced.

[0055] Among them, preferably, a part of the gaseous sulfur trioxide in the gas is separated into pure sulfur trioxide product 18 in the heat recovery condensing device 16, and the remaining uncondensed gas phase components are used as non-condensable gas, which is connected to the primary sulfur incinerator 3 and the secondary sulfur incinerator 5 through the gas phase outlet of the heat recovery condensing device 16 to participate in the next cycle of the production process; an exhaust gas discharge process is added on the way from the gas phase outlet pipeline of the heat recovery condensing device 16 to the primary sulfur incinerator 3 and the secondary sulfur incinerator 5, and a small part of the non-condensable gas is treated by the exhaust gas absorption system 17.

[0056] Among them, it is necessary to control the excess of pure oxygen 2 entering the first stage of the converter to ensure the conversion rate of sulfur dioxide;

[0057] Among them, some uncondensed sulfur trioxide and excess oxygen remaining from the reaction must be retained as circulating gas. Sulfur trioxide should account for the largest proportion of the circulating gas to avoid excessive oxygen content in the furnace gas after returning to the furnace, forming a high-oxygen environment that damages the equipment in the furnace.

[0058] Among them, the cold side medium in the heat recovery condensing device is desalted water, which absorbs the heat energy in the process gas, increases the temperature of the desalted water, and saves the steam energy consumption of the system;

[0059] The working principle and beneficial effects of the above technical solution are as follows: liquid sulfur 1, one of the pure oxygen 2, and the SO3-containing non-condensable gas transported from the gas phase outlet main of the heat recovery condensing device 16 enter the primary sulfur incinerator 3 and the secondary sulfur incinerator 5 respectively and mix, so that the liquid sulfur is fully burned in each furnace to generate sulfur dioxide gas and release a large amount of heat; the outlet gas of the primary sulfur incinerator 3 enters the primary combustion heat recovery device 4 for cooling, and the cooled process gas enters the secondary sulfur incinerator 5 to be mixed with the liquid sulfur and pure oxygen that enter the secondary sulfur incinerator separately for combustion, and the high-temperature gas at the outlet of the secondary sulfur incinerator 5 enters the secondary combustion heat recovery device 6 for cooling.

[0060] The process gas at the outlet of the secondary combustion heat recovery device 6 is mixed with another stream of pure oxygen 2 gas and enters the first stage of the converter 7. The temperature of the process gas after the first stage of catalytic oxidation is increased, and the process gas at the outlet of the first stage enters the high-temperature heat recovery device 8 for heat exchange, and then enters the second stage of the converter 9; the temperature of the process gas after the second stage of catalytic oxidation is increased again, and the process gas at the outlet of the second stage enters the medium-temperature heat recovery device 10 for heat exchange again, and enters the third stage of the converter 11 for reaction; the process gas exiting the third stage of the converter 11 enters the low-temperature heat recovery device 12, the economizer 13, and the heat exchanger 14 for heat exchange in turn, so as to ensure that the heat energy in the process gas is fully utilized before entering the compressor 15, and the temperature of the process gas is greatly reduced;

[0061] The process gas from the heat exchanger 14 enters the compressor 15, where the compressor 15 does work, and the mechanical energy is converted into the internal energy of the process gas. The volume of the process gas decreases, the gas pressure increases, and the temperature rises again; the heated process gas enters the heat recovery condensing device 16 for compressor mechanical heat recovery and condensation with the finished pure sulfur trioxide; a portion of the gaseous sulfur trioxide in the process gas is separated into the pure sulfur trioxide finished product 18 in the heat recovery condensing device 16 for extraction, and the remaining uncondensed gas phase components are used as non-condensable gas and re-enter the primary sulfur incinerator 3 through the gas phase outlet pipeline of the heat recovery condensing device 16 to participate in the next cycle of the process system; an exhaust gas discharge process is added on the way from the gas phase outlet pipeline of the heat recovery condensing device 16 to the primary sulfur incinerator 3, and a small portion of the non-condensable gas can be continuously or intermittently discharged to the exhaust gas absorption system 17 for treatment.

[0062] Using pure oxygen and liquid sulfur as raw materials, sulfur trioxide is produced continuously without any by-products, with excellent yield and pure product quality.

[0063] A gas circulation system is set up to achieve extremely high raw material utilization rate.

[0064] The finished pure sulfur trioxide is separated from the system by first compressing the gas and then condensing it, which gets rid of the constraint of additional acid production in the traditional oleum method, avoids the waste of raw materials, reduces the energy consumption of the product, and greatly improves the economic benefits of the device.

[0065] Setting up two sulfur incinerators in series to burn sulfur can maintain the total rated sulfur injection volume while reducing the combustion temperature of a single sulfur incinerator to a certain extent, avoiding the generation of a high-temperature and high-oxygen environment in the furnace. While ensuring product output, it can further protect the sulfur incinerator-related equipment and extend the life of the device.

[0066] Example 3

[0067] Preparation of mixed particles: 1 part of diatomaceous earth, 7 parts of corundum balls and 3 parts of alumina particles were mixed by a particle preparation device, 10 parts of polydimethylpolysiloxane wetting agent were added, and mixed particles were obtained after grinding and drying. The particle size of the obtained mixed particles was 200 nm.

[0068] 0.2 parts of aminovanadate and 4 parts of hexaisopropoxide tungsten were dissolved in 60 parts of N,N-dimethylformamide solution, 2 parts of nano sodium molybdate were added, and then 10 parts of mixed particles were added. After ultrasonic dispersion in a 50W ultrasonic machine for 30 minutes, the spinning solution was stirred evenly to obtain a spinning solution; the spinning solution was electrostatically spun to obtain a VW-alumina fiber membrane, the electrostatic spinning voltage was 15kV, and the spinning solution flow rate was 1mm / min. After drying at 150℃ for 10 hours, it was placed on quartz, put into a tubular heating furnace, and heated to 300℃ under a nitrogen atmosphere (flow rate of 600ml / min), hydrogen was introduced (flow rate of 200ml / min), and the reaction was carried out for 30 minutes, and the temperature was raised to 600℃, acetylene was introduced (flow rate of 50ml / min), and the reaction was carried out for 60 minutes, and the vanadium pentoxide tungsten molybdenum-carbon nanotubes were obtained. The obtained vanadium pentoxide tungsten molybdenum-carbon nanotubes are blended with PTFE fibers and aluminum silicate fibers to obtain vanadium pentoxide tungsten molybdenum-carbon nanotubes / PTFE-aluminum silicate catalysts, wherein the mass ratio of vanadium pentoxide tungsten molybdenum-carbon nanotubes to PTFE fibers and aluminum silicate fibers is 4.5:3:4.

[0069] Example 4

[0070] Preparation of mixed particles: 1 part of diatomaceous earth, 7 parts of corundum balls and 3 parts of alumina particles were mixed by a particle preparation device, 10 parts of polydimethylpolysiloxane wetting agent were added, and mixed particles were obtained after grinding and drying. The particle size of the obtained mixed particles was 300 nm.

[0071] 0.2 parts of aminovanadate and 4 parts of hexaisopropoxide tungsten were dissolved in 60 parts of N,N-dimethylformamide solution, 3 parts of nano sodium molybdate were added, and then 8 parts of mixed particles were added. After ultrasonic dispersion in a 50W ultrasonic machine for 30 minutes, the spinning solution was stirred evenly to obtain a spinning solution; the spinning solution was electrostatically spun to obtain a VW-alumina fiber membrane, the electrostatic spinning voltage was 15kV, and the spinning solution flow rate was 1mm / min. After drying at 150℃ for 10 hours, it was placed on quartz, put into a tubular heating furnace, and heated to 300℃ under a nitrogen atmosphere (flow rate of 600ml / min), hydrogen was introduced (flow rate of 200ml / min), reacted for 30min, heated to 600℃, acetylene was introduced (flow rate of 50ml / min), reacted for 60min, and cooled under a nitrogen atmosphere to obtain vanadium pentoxide tungsten molybdenum-carbon nanotubes. The obtained vanadium pentoxide tungsten molybdenum-carbon nanotubes are blended with PTFE fibers and aluminum silicate fibers to obtain vanadium pentoxide tungsten molybdenum-carbon nanotubes / PTFE-aluminum silicate catalysts, wherein the mass ratio of vanadium pentoxide tungsten molybdenum-carbon nanotubes to PTFE fibers and aluminum silicate fibers is 4:2:3.

[0072] Example 5

[0073] Preparation of mixed particles: 1 part of diatomaceous earth, 7 parts of corundum balls and 3 parts of alumina particles were mixed by a particle preparation device, 10 parts of polydimethylpolysiloxane wetting agent were added, and mixed particles were obtained after grinding and drying. The particle size of the obtained mixed particles was 500 nm.

[0074] 0.2 parts of aminovanadate and 4 parts of hexaisopropoxide tungsten were dissolved in 60 parts of N,N-dimethylformamide solution, 2 parts of nano sodium molybdate were added, and then 8 parts of mixed particles were added. After ultrasonic dispersion in a 50W ultrasonic machine for 30 minutes, the spinning solution was stirred evenly to obtain a spinning solution; the spinning solution was electrostatically spun to obtain a VW-alumina fiber membrane, the electrostatic spinning voltage was 15kV, and the spinning solution flow rate was 1mm / min. After drying at 150℃ for 10 hours, it was placed on quartz, put into a tubular heating furnace, and heated to 300℃ under a nitrogen atmosphere (flow rate of 600ml / min), hydrogen was introduced (flow rate of 200ml / min), reacted for 30min, heated to 600℃, acetylene was introduced (flow rate of 50ml / min), reacted for 60min, and cooled under a nitrogen atmosphere to obtain vanadium pentoxide tungsten molybdenum-carbon nanotubes. The obtained vanadium pentoxide tungsten molybdenum-carbon nanotubes are blended with PTFE fibers and aluminum silicate fibers to obtain vanadium pentoxide tungsten molybdenum-carbon nanotubes / PTFE-aluminum silicate catalysts, wherein the mass ratio of vanadium pentoxide tungsten molybdenum-carbon nanotubes to PTFE fibers and aluminum silicate fibers is 5:3:3.

[0075] Comparative Example 1

[0076] The difference from Example 3 is the lack of mixed particles in equal weight portions, and the other aspects are the same.

[0077] Comparative Example 2

[0078] The difference from Example 3 is the lack of an equal weight portion of aluminum silicate fiber, and the rest are the same.

[0079] Performance Test The stability test of Example 3 and the comparative example was carried out for 24 and 72 hours. The results are shown in Table 1.

[0080] Table 1

[0081]

[0082] Example 5

[0083] See also Figure 3-5The particle preparation device includes: a preparation shell 19 and a conical heating element 51, a conical heating element 51 is fixedly provided at the bottom of the preparation shell 19, a supporting foot 36 is installed at the bottom of the conical heating element 51, a transmission chamber 20, a guide chamber 21, a transmission chamber 23, a grinding chamber 33 and a transmission chamber 3 46 are opened in the preparation shell 19, a crankshaft assembly 31 is installed in the transmission chamber 23, and one end of the crankshaft assembly 31 is movably extended into the transmission chamber 20, and the other end of the crankshaft assembly 31 is fixedly connected to the top of the drive shaft 30, and one end of the two groups of crankshaft assemblies 31 extending into the transmission chamber 20 are fixedly sleeved with a pulley 24, and the two groups of pulleys 24 are connected to each other through a belt 22 for transmission, and the guide block 26 is connected to the crankshaft assembly through a first connecting rod 25 The first connecting rod 25 is hinged to the second connecting rod 25, and the other end of the second connecting rod 27 is hinged to the fixing member 29. The grinding head 37 and the rotating grinding sleeve 39 are both installed in the grinding chamber 33, and the grinding head 37 and the rotating grinding sleeve 39 are provided with the same grinding teeth 38 on the side close to each other. The grinding head 37 is connected to the fixing member 29 through the second connecting rod 28. The rotating grinding sleeve 39 is movably connected to the inner wall of the grinding chamber 33, and the outer wall of the rotating grinding sleeve 39 is fixedly sleeved with a gear 2 41, and the gear 1 40 is fixedly sleeved on the outer wall of the driving shaft 30, and the gear 1 40 and the gear 2 41 are meshed. A filter screen 42 is installed at the connection between the bottom of the grinding chamber 33 and the feeding channel 50, and an annular The rolling piece 44 is rotatably connected to the inner wall of the feeding channel 50 through the rotating shaft 43, and the bottom of the rotating shaft 43 on one side extends into the transmission chamber 3 46, the pulley 2 45 is fixedly sleeved on the outer wall of the driving shaft 30, the pulley 3 49 is fixedly sleeved on the outer wall of the rotating shaft 43 extending into the transmission chamber 3 46, the pulley 2 45 and the pulley 3 49 are connected by the belt 2 48, the driving motor 1 47 is installed in the preparation shell 19, and the output shaft of the driving motor 1 47 is fixedly connected to the bottom of the driving shaft 30, the outer wall of the preparation shell 19 is provided with a feeding bin 32, and the feeding bin 32 is connected with the grinding chamber 33 through the feeding channel 34, the shell of the conical heating element 51 is embedded with a heating wire 52, and the top of the conical heating element 51 is provided with a The feeding port 35, the circulating material barrel 53 is fixedly connected to the inner wall of the conical heating element 51 through the fixing rod 54, the bottom of the circulating material barrel 53 is fixedly connected to the inner wall of the conical heating element 51 through the supporting ring 55, the pushing block 56 is movably arranged in the conical heating element 51, the circulating material barrel 53 is a structure with upper and lower openings, and the diameter of the pushing block 56 is smaller than the inner diameter of the circulating material barrel 53, the motor fixing plate 58 is fixedly connected to the supporting foot 36, and the motor fixing plate 58 is installed with a driving motor 2 59, the output end of the driving motor 2 59 is fixedly connected to the bottom of the third connecting rod 57 through the crankshaft assembly 2 60, the top of the third connecting rod 57 movably extends into the conical heating element 51 and is fixedly connected to the pushing block 56, the outer wall of the conical heating element 51 is provided with a discharge port 61, and a solenoid valve is installed on the discharge port 61.

[0084] The working principle and beneficial effects of the above technical solution are as follows: while diatomaceous earth, corundum balls and alumina particles are fed into the grinding chamber 33 through the feeding bin 32 along the feeding channel 34, the driving motor 47 is started, and the crankshaft assembly 31 on the left side is driven to reciprocate through the driving shaft 30, and then the crankshaft assembly 31 on the right side is also driven to reciprocate through the cooperation of the two sets of pulleys 24 and the belt 22. At this time, the first connecting rod 25 will drive the guide block 26 to move back and forth, so that the fixing part 29 can be driven to move back and forth up and down along the guide cavity 21 through the second connecting rod 27. At the same time, the rotating grinding sleeve 39 rotates in cooperation with the gear 1 40 and the gear 2 41. Through the above method, the particles falling into the grinding cavity 33 can be ground, and the up and down reciprocating movement of the grinding head 37 can improve the grinding efficiency. After grinding, the qualified mixed material enters the feed channel 50 through the filter screen 42, continues to be further rolled between the two groups of rotating annular rolling parts 44, and then falls through the feed port 35 to accumulate on the pusher block 56 in the cavity of the conical heating element 51. At this time, the crankshaft assembly 2 60 is driven to rotate by starting the drive motor 2 59. , and then the crankshaft assembly 2 60 pushes the pushing block 56 to move reciprocatingly up and down through the third connecting rod 57. When moving upward, the mixed material is pushed into the circulating material barrel 53 until it reaches its top, and part of the mixed material will overflow between the circulating material barrel 53 and the inner wall of the conical heating element 51 and slide down along the inner wall of the conical heating element 51. In this process, the heat emitted by the heating wire 52 can dry the mixed material, and in the process of the pushing block 56 falling back, it continues to fall back onto the pushing block 56 through the gap left between the support ring 55 and the inner wall of the conical heating element 51. The reciprocating movement of the pushing block 56 up and down can drive the mixed material to flip back and forth and greatly improve the drying speed with the assistance of the heating wire 52. After the drying is completed, the mixed material is discharged by opening the solenoid valve on the discharge port 61.

[0085] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. If these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A process for preparing pure sulfur trioxide by three-stage conversion of pure oxygen in a double sulfur incinerator, characterized in that: The following steps are involved: Step 1 is a sulfur incineration reaction process: liquid sulfur (1) and pure oxygen (2) are sent to a primary sulfur incinerator (3) and a secondary sulfur incinerator (5) for combustion to generate sulfur dioxide, and then the sulfur dioxide is converted into sulfur trioxide through a three-stage converter, and a composite carrier-supported vanadium pentoxide tungsten-molybdenum catalyst is used in the process; Step 2 is a heat recovery process: the chemical heat energy generated in step 1 is collected; Step 3 is a condensation separation process: the generated sulfur trioxide (18) is collected as a finished product, and the mechanical heat energy generated is also recovered through a heat recovery process.

2. The process for preparing pure sulfur trioxide by three-stage conversion of pure oxygen by double sulfur incinerators according to claim 1, characterized in that: The sulfur burning reaction process comprises a primary sulfur burning furnace (3), a secondary sulfur burning furnace (5) and a three-stage converter, wherein the three-stage converter comprises a first stage converter (7), a second stage converter (9) and a third stage converter (11), wherein liquid sulfur (1) and one stream of pure oxygen (2) are introduced into the primary sulfur burning furnace (3) and the second stage converter (5) to start combustion, wherein the gas generated by the combustion of the primary sulfur burning furnace (3) is introduced into the second stage converter (5), wherein the gas generated by the combustion of the primary sulfur burning furnace (3) is mixed with the liquid sulfur and pure oxygen separately introduced into the second stage converter (5) and combusted, and the gas after combustion passes through the first stage converter (7), the second stage converter (9) and the third stage converter (11) in sequence.

3. The process for preparing pure sulfur trioxide by three-stage conversion of pure oxygen by double sulfur incinerators according to claim 1, characterized in that: The heat recovery process comprises a primary combustion heat recovery device (4), a secondary combustion heat recovery device (6), a high temperature heat recovery device (8), a medium temperature heat recovery device (10), a low temperature heat recovery device (12), and a coal economizer (13); the gas generated by the combustion of the primary sulfur incinerator (3) enters the primary combustion heat recovery device (4) for cooling, and then the gas is passed into the secondary sulfur incinerator (5); the gas generated by the combustion of the secondary sulfur incinerator (5) enters the secondary combustion heat recovery device (6) for cooling; the gas cooled by the secondary combustion heat recovery device (6) is mixed with another stream of pure oxygen (2) and then enters the first stage of the converter (7); the temperature of the gas is increased after the first stage of catalytic oxidation, and the gas at the first stage outlet enters the high temperature heat recovery device (8) for heat exchange, and then enters the second stage of the converter (9); the temperature of the gas is increased again after the second stage of catalytic oxidation, and the gas at the second stage outlet enters the medium temperature heat recovery device (10) for heat exchange again, and then enters the third stage of the converter (11) for reaction; the gas exiting the third stage of the converter (11) enters the low temperature heat recovery device (12) and the coal economizer (13) in sequence.

4. The process for preparing pure sulfur trioxide by three-stage conversion of pure oxygen by double sulfur incinerators according to claim 3 is characterized in that: The condensation separation process includes a heat exchanger (14), a compressor (15), and a heat recovery condensation device (16); the gas at the outlet of the economizer (13) enters the heat exchanger (14) for heat exchange, the heat energy in the gas is fully utilized, and the temperature of the gas is greatly reduced; then the gas enters the compressor (15), and the compressor (15) does work, the mechanical energy is converted into the internal energy of the gas, the gas volume is reduced, the gas pressure is increased, and the temperature is increased again; the heated gas enters the heat recovery condensation device (16) to recover the mechanical heat energy of the compressor and condense the finished pure sulfur trioxide (18) before being produced.

5. The process for preparing pure sulfur trioxide by three-stage conversion of pure oxygen by double sulfur incinerators according to claim 4, characterized in that: A portion of the gaseous sulfur trioxide in the gas is separated into pure sulfur trioxide product (18) in the heat recovery condensing device (16) and taken out, and the remaining uncondensed gas phase components are used as non-condensable gas and connected to the primary sulfur incinerator (3) and the secondary sulfur incinerator (5) through the gas phase outlet of the heat recovery condensing device (16) to participate in the next cycle of the production process; an exhaust gas discharge process is added on the way from the gas phase outlet pipeline of the heat recovery condensing device (16) to the primary sulfur incinerator (3) and the secondary sulfur incinerator (5), and a small portion of the non-condensable gas is processed by the exhaust gas absorption system (17).

6. The process for preparing pure sulfur trioxide by three-stage conversion of pure oxygen by double sulfur incinerators according to claim 1, characterized in that: The preparation method of the composite carrier-supported vanadium pentoxide tungsten-molybdenum catalyst comprises the following steps: Step 1: Mixed particle preparation: diatomaceous earth, ball milling medium and alumina particles are mixed by a particle preparation device, a wetting agent is added, and then ball milling, grinding and drying are performed to obtain mixed particles; Step 2: dissolving the precursor of vanadium pentoxide and the precursor of tungsten in N,N-dimethylformamide solution, adding nano sodium molybdate and mixed particles, and stirring after ultrasonic dispersion to obtain a spinning solution; Step 3, electrospinning the spinning solution obtained in step 2 to obtain a fiber membrane, placing it on quartz after drying, placing it in a tubular heating furnace, heating it under a nitrogen atmosphere, introducing hydrogen to react, heating it to introduce acetylene to react, cooling it under a nitrogen atmosphere, and obtaining vanadium pentoxide tungsten molybdenum-carbon nanotubes; Step 4: blending the vanadium pentoxide tungsten molybdenum-carbon nanotubes obtained in step 3 with polytetrafluoroethylene fibers and aluminum silicate fibers to obtain a product.

7. The process for preparing pure sulfur trioxide by three-stage conversion of pure oxygen by double sulfur incinerators according to claim 6, characterized in that: In the preparation method of the composite carrier-supported vanadium pentoxide-tungsten-molybdenum catalyst, the precursor of vanadium pentoxide in step 1 is aminovanadate; Preferably, the tungsten precursor is one or both of tungsten hexacarbonyl and tungsten hexaisopropoxide; Preferably, the ball milling medium is corundum ball, and the wetting agent is polydimethylpolysiloxane.

8. The process for preparing pure sulfur trioxide by three-stage conversion of pure oxygen by double sulfur incinerators according to claim 6, characterized in that: The weight ratio of diatomaceous earth, ball milling medium and alumina particles in step 1 of the preparation method of the composite carrier loaded vanadium pentoxide tungsten molybdenum catalyst is 1:7:3; Preferably, the weight ratio of the nano-sodium molybdate and the mixed particles added in step 2 is (2-3):(8-10).

9. The process for preparing pure sulfur trioxide by three-stage conversion of pure oxygen by double sulfur incinerators according to claim 6, characterized in that: In the preparation method of the composite carrier-supported vanadium pentoxide tungsten-molybdenum catalyst, in step 3, the electrospinning voltage is 10-20 kV, the spinning solution flow rate is 0.1-1 mm / min, and the calcination temperature is 600-900° C.; Preferably, in step 3, the flow rate of hydrogen introduced is 200 ml / min, and the flow rate of acetylene introduced is 50 ml / min.

10. The process for preparing pure sulfur trioxide by three-stage conversion of pure oxygen by double sulfur incinerators according to claim 6, characterized in that: In step 4 of the method for preparing the composite carrier-loaded vanadium pentoxide tungsten-molybdenum catalyst, the mass ratio of vanadium pentoxide tungsten-molybdenum-carbon nanotubes to PTFE fibers and aluminum silicate fibers is (4-5): (2-3): (3-4).

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