Production process for preparing high-purity sulfur trioxide from high-efficiency pure oxygen by using tandem double-furnace two-stage conversion method

Abstract

The invention discloses a production process for preparing high-purity sulfur trioxide from high-efficiency pure oxygen through a serial double-furnace two-stage conversion method. The production process comprises the following steps: S1, preparing sulfur dioxide; s2, preparing sulfur trioxide; s3, condensing and separating sulfur trioxide; and S4, recovering the non-condensable gas to enter the next cycle. According to the method, pure oxygen and liquid sulfur are used as raw materials, the sulfur trioxide finished product is continuously produced, no by-product is generated, and the yield of the finished product is close to 100%. The double sulfur burning furnaces are connected in series to burn liquid sulfur, the liquid sulfur is primarily burnt by the first-stage sulfur burning furnace to generate sulfur dioxide, and the sulfur dioxide enters the first-stage heat recoverer to be cooled, so that the heat load of the second-stage sulfur burning furnace is reduced. The staged treatment mode is beneficial to more accurate management of the temperature in each furnace, reduces the risk of equipment damage caused by overheating, prolongs the service life of the equipment, and ensures stable operation of the device.

Description

Technical Field

[0001] The invention relates to the technical field of sulfur trioxide preparation, and in particular to a production process for preparing high-purity sulfur trioxide with high-efficiency pure oxygen by a two-stage conversion method using two series furnaces. Background Art

[0002] In the current chemical industry, the production of pure sulfur trioxide mainly relies on the oleum method, which is deeply rooted in the traditional sulfur / pyrite acid production process. Although this process has been optimized and improved for a long time, it still faces many challenges in improving the yield and purity of pure sulfur trioxide.

[0003] In the traditional process, sulfur or pyrite reacts with oxygen at high temperature to generate sulfur dioxide, which is then further oxidized to sulfur trioxide under the action of a catalyst. However, most of the sulfur trioxide generated in this conversion process is not directly collected in pure form, but is combined with desalted water added to the dry absorption system and converted into sulfuric acid or oleum. Although this step effectively utilizes the reaction products, it limits the output of pure sulfur trioxide, because the extraction of pure sulfur trioxide from sulfuric acid or oleum requires a complex distillation and cooling liquefaction process, which is not only energy-intensive, but also difficult to achieve a satisfactory yield. What is even more difficult is that when air is used as an oxidant to react with sulfur, the generated flue gas contains a large amount of nitrogen, oxygen, and unavoidable nitrogen oxides and other by-products in addition to sulfur trioxide. The presence of these impurities makes it extremely difficult to directly separate and purify sulfur trioxide from the flue gas. Traditional separation technologies often fail to meet the ideal purity requirements, while also increasing production costs and environmental pollution risks. Summary of the invention

[0004] Based on the problems existing in the background technology, the present invention provides a production process for preparing high-purity sulfur trioxide from pure oxygen by a two-stage conversion method using two furnaces in series. Pure oxygen and liquid sulfur are used as raw materials to continuously produce finished sulfur trioxide products without generating any by-products, and the finished product yield is close to 100%.

[0005] The present invention is implemented by the following technical solutions:

[0006] A production process for preparing high-purity sulfur trioxide from pure oxygen using a two-stage conversion method with two furnaces in series, comprising the following steps:

[0007] S1. Preparation of sulfur dioxide: Liquid sulfur in the liquid sulfur tank and pure oxygen in the pure oxygen tank are mixed in the primary sulfur incinerator and the secondary sulfur incinerator. The liquid sulfur is fully burned in the furnace to generate sulfur dioxide. The gas at the outlet of the primary sulfur incinerator is cooled in the primary combustion heat recovery device. After cooling, it enters the secondary sulfur incinerator and is mixed with the liquid sulfur and pure oxygen that enter the secondary sulfur incinerator separately. The gas at the outlet of the secondary sulfur incinerator is cooled in the secondary combustion heat recovery device.

[0008] S2. Preparation of sulfur trioxide: The outlet gas of the secondary combustion heat recovery device is mixed with the pure oxygen in the pure oxygen tank and enters the first stage of the converter to undergo a catalytic oxidation reaction of sulfur dioxide. The outlet gas of the first stage of the converter enters the high-temperature heat recovery device for heat exchange and then enters the second stage of the converter to undergo a second stage of catalytic oxidation reaction. The outlet gas of the second stage of the converter enters the warm heat recovery device for heat exchange again. The outlet gas of the warm heat recovery device enters the economizer and the heat exchanger in sequence for heat exchange;

[0009] S3. Sulfur trioxide condensation and separation: The gas at the heat exchanger outlet enters the compressor for compression, the gas volume is reduced, and the temperature is increased. After the temperature is increased, the gas enters the heat recovery condensation device for compressor mechanical heat energy recovery and condensation with the finished pure sulfur trioxide. The gas is separated into pure sulfur trioxide products in the heat recovery condensation device and enters the pure sulfur trioxide tank;

[0010] S4. Recover the non-condensable gas and enter the next cycle: the remaining uncondensed gas in the heat recovery condensing device is treated as non-condensable gas and re-enters the primary sulfur incinerator and the secondary sulfur incinerator through the gas phase outlet pipe of the heat recovery condensing device to participate in the next cycle of the process system and form a gas phase closed circulation system.

[0011] Furthermore, in step S1, the liquid sulfur and pure oxygen enter the primary sulfur incinerator, including the non-condensable gas at the gas phase outlet of the heat recovery condensation device in step S4, and the ratio of the total amount of pure oxygen in the primary sulfur incinerator to the amount of liquid sulfur is (1.1-1.3):1;

[0012] Liquid sulfur and pure oxygen enter the secondary sulfur incinerator. The ratio of the total amount of pure oxygen in the secondary sulfur incinerator to the amount of liquid sulfur is (1-1.1):1. The concentration of pure oxygen in the secondary sulfur incinerator is lower than that in the primary sulfur incinerator.

[0013] Furthermore, in step S1, the primary combustion heat recovery device reduces the gas temperature to 650±20°C; the secondary combustion heat recovery device reduces the gas temperature to 400±10°C.

[0014] Furthermore, in step S2, the outlet gas of the secondary combustion heat recovery device is mixed with pure oxygen in a volume ratio of (2.05-2.2):1.

[0015] Furthermore, in step S2, after the first-stage outlet gas of the converter enters the high-temperature heat recovery device for heat exchange, the gas temperature drops to 450±10°C.

[0016] Furthermore, in step S2, after the outlet gas of the second stage of the converter enters the warm heat recovery device for heat exchange again, the gas temperature drops to 200±10°C.

[0017] Furthermore, in step S2, the outlet gas of the medium-temperature heat recovery device enters the economizer and the heat exchanger in sequence for heat exchange, and the gas temperature drops to 45-50°C.

[0018] Furthermore, in step S3, the gas at the outlet of the heat exchanger enters the compressor and is compressed to 2-3 MPa, and the gas temperature reaches 200-250°C.

[0019] Furthermore, in step S4, a tail gas discharge process is added on the way from the gas phase outlet pipeline of the heat recovery condensing device to the incinerator, and a small part of the non-condensable gas can be continuously or intermittently discharged to the tail gas absorption system for treatment.

[0020] Furthermore, in step S1, a filter assembly is connected to the outlet of the liquid sulfur tank, and the liquid sulfur in the liquid sulfur tank enters the primary sulfur incinerator and the secondary sulfur incinerator through the filter assembly;

[0021] Furthermore, the filter assembly includes a filter box, a partition is provided in the filter box, the partition divides the filter box into two filter chambers, filter plates are slidably provided in the filter chambers, two inclined plates are provided on the right side of the filter plate, the two inclined plates are used to aggregate liquid sulfur, the inclined plates are fixedly installed in the filter chamber, two rotating rods that are symmetrical up and down and front and back are provided on the right side of the inclined plate, the rotating rods are rotatably connected to the filter chamber, a number of adsorption plates are fixedly provided on the rotating rod, a rotating shaft is provided on the right side of the rotating rod, the rotating shaft is rotatably connected to the filter chamber, a number of adsorption strips are fixedly provided on the rotating shaft, a rotating cylinder is fixedly provided on the other end of the number of adsorption strips, a number of through grooves are provided on the rotating cylinder, the through grooves and the adsorption strips are staggered, the rotating cylinder is in contact with the inner wall of the filter chamber, and a liquid outlet pipe is also connected to the filter chamber, and the two liquid outlet pipes are respectively connected to the primary sulfur incinerator and the secondary sulfur incinerator after being connected.

[0022] Furthermore, an L-shaped plate is fixedly arranged on the right side of the filter box, a pressure sensor is arranged on the L-shaped plate, a front-to-back symmetrical spring is fixedly arranged on the L-shaped plate, the other end of the spring is fixedly connected to a moving rod, the moving rod slides and extends into the filter cavity, the moving rod is fixedly connected to the filter plate, a groove is opened on the lower side wall of the filter box, and the moving rod is slidably arranged in the groove;

[0023] Furthermore, the rotating rod is rotated upward to extend out of the filter box, the rotating rod is set to be hollow, a plurality of air holes are set on the rotating rod, the upper end of the rotating rod is rotatably connected to a water pipe, the water pipe is fixedly installed on the filter box, a connecting pipe is connected to the water pipe, the other end of the connecting pipe is connected to a water pump, the water pump is fixedly installed on the filter box, the water pipe is also connected to a front-to-back symmetrical cleaning pipe, the other end of the cleaning pipe is connected to a spray pipe, two openings are set on the upper side wall of the filter box, the spray pipe is rotatably installed at the opening, an arc-shaped rack is set on the spray pipe, and a plurality of nozzles are set on the spray pipe;

[0024] Furthermore, a liquid inlet hole is provided on the left side of the filter chamber, a slide plate is slidably provided on the left side wall of the filter box, a liquid inlet pipe is installed through the slide plate, a liquid storage box is connected to the liquid inlet pipe, the liquid storage box is fixedly connected to the slide plate, a lifting plate is slidably provided in the liquid storage box, a linear drive member 1 is fixedly provided on the upper end of the liquid storage box, the lower output end of the linear drive member 1 slides and extends into the liquid storage box, the lower output end of the linear drive member 1 is fixedly connected to the lifting plate, a front-to-back symmetrical linear drive member 2 is provided on the filter box, the right output end of the linear drive member 2 is fixedly connected to a gear rod, the gear rod is meshed with an arc-shaped rack, a linear drive member 3 is fixedly connected to the left side wall of the filter box, the output end of the linear drive member 3 is fixedly connected to the slide plate, and the linear drive member 3 is electrically connected to the pressure sensor;

[0025] Furthermore, a gear 1 and a sector gear are fixedly provided on the rotating rod, the two gear 1s located on the same filter chamber are meshed and connected, the two sector gears located on the same filter chamber are symmetrically distributed along the tangent direction of the meshing position of the two gear 1s, and a front-to-back symmetrical tooth block is slidably provided on the upper side wall of the filter box, the tooth block is alternately meshed with the two sector gears, the rotating shaft rotates upward and extends out of the filter box, and a gear 2 is fixedly provided on the rotating shaft, and the tooth block is meshed and connected with the gear 2.

[0026] Beneficial effects of the present invention:

[0027] 1. The present invention uses pure oxygen and liquid sulfur as raw materials. Compared with air oxidation, it reduces the participation of unnecessary inert gases such as nitrogen, improves the utilization rate of oxygen and the reaction rate, continuously produces sulfur trioxide products, does not produce by-products, has a finished product yield of nearly 100%, and has pure product quality.

[0028] 2. The present invention sets up two sulfur incinerators in series to burn liquid sulfur, which ensures the overall sulfur injection amount of the device while effectively controlling the temperature in the furnace through step-by-step combustion. After the first-level sulfur incinerator initially burns liquid sulfur to generate sulfur dioxide, it enters the first-level heat recovery device for cooling, reducing the heat load of the second-level sulfur incinerator. This staged treatment method helps to more accurately manage the temperature in each furnace, reduce the risk of equipment damage due to overheating, extend the life of the equipment, and ensure the stable operation of the device. At the same time, step-by-step combustion also improves energy utilization efficiency, helps to reduce unnecessary heat loss and equipment maintenance frequency, and improves overall production efficiency.

[0029] 3. The gas circulation system provided in the present invention allows unreacted gas and uncondensed sulfur trioxide to be reused, thereby improving the utilization rate of raw materials. This design reduces the consumption and waste of raw materials, and due to the recycling of reactants, the scale of the device can be controlled, and no overly large equipment is required, thereby saving space and capital investment.

[0030] 4. In the present invention, the finished pure sulfur trioxide is separated from the system by first compressing the gas and then condensing it, which avoids the acid treatment step in the traditional oleum method, thereby simplifying the process flow and reducing the difficulty of operation. This method effectively reduces the corrosive load of the equipment and reduces the requirements for equipment materials, which is beneficial to extending the service life of the equipment. The efficient reaction and separation process reduces energy consumption, making the production more energy-saving and environmentally friendly. Reducing energy consumption not only helps to improve the economic benefits of the device, but also helps to reduce the negative impact on the environment. Through the method of gas compression and condensation separation, the optimization of process energy consumption further improves the economy of the overall device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are used to provide further explanation 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:

[0032] Figure 1 It is the material flow chart of the present invention;

[0033] Figure 2 It is a process flow chart of the present invention;

[0034] Figure 3 The structure of the filter box of the present invention is shown in FIG. Figure 1 ;

[0035] Figure 4 The structure of the filter box of the present invention is shown in FIG. Figure 2 ;

[0036] Figure 5 It is a structural schematic diagram of the rotating rod of the present invention;

[0037] Figure 6 It is a schematic diagram of the meshing of the sector gear and the gear block of the present invention;

[0038] Figure 7 It is a structural schematic diagram of the ejection pipe of the present invention;

[0039] Figure 8 It is a structural schematic diagram of the slide plate of the present invention.

[0040] Among them, 1. Liquid sulfur tank, 2. Pure oxygen tank, 3. Primary sulfur incinerator, 4. Primary combustion heat recovery device, 5. Secondary sulfur incinerator, 6. Secondary combustion heat recovery device, 7. Converter stage 1, 8. High temperature heat recovery device, 9. Converter stage 2, 10. Medium temperature heat recovery device, 11. Economizer, 12. Heat exchanger, 13. Compressor, 14. Heat recovery condensing device, 15. Tail gas system, 16. Pure sulfur trioxide tank, 17. Filter box, 18. Filter plate, 19. Partition, 20. Liquid storage box, 21. Filter chamber, 22. Inclined plate, 23. Rotating rod, 24. Adsorption strip, 25. Moving rod, 26, liquid outlet pipe, 27, pressure sensor, 28, L-shaped plate, 29, spring, 30, rotating shaft, 31, through groove, 32, rotating cylinder, 33, adsorption plate, 34, air hole, 35, water pump, 36, gear two, 37, connecting pipe, 38, spray pipe, 39, linear drive component two, 40, linear drive component three, 41, cleaning pipe, 42, gear rod, 43, water pipe, 44, gear block, 45, fan gear, 46, lifting plate, 47, liquid inlet pipe, 48, slide plate, 49, arc rack, 50, nozzle, 51, linear drive component one, 52, gear one. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only partial embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] refer to Figure 1 and Figure 2 The present invention provides a production process for preparing high-purity sulfur trioxide from pure oxygen using a two-stage conversion method with two furnaces in series, comprising the following steps:

[0043] A production process for preparing high-purity sulfur trioxide from pure oxygen using a two-stage conversion method with two furnaces in series, comprising the following steps:

[0044] S1. Preparation of sulfur dioxide: Liquid sulfur in the liquid sulfur tank 1 and pure oxygen in the pure oxygen tank 2 enter the primary sulfur incinerator 3 and the secondary sulfur incinerator 5 for mixing, the liquid sulfur is fully burned in the furnace to generate sulfur dioxide, the gas at the outlet of the primary sulfur incinerator 3 enters the primary combustion heat recovery device 4 for cooling, and then enters the secondary sulfur incinerator 5 after cooling, and is mixed with the liquid sulfur and pure oxygen entering the secondary sulfur incinerator 5 separately for combustion, and the gas at the outlet of the secondary sulfur incinerator 5 enters the secondary combustion heat recovery device 6 for cooling; in order to avoid the generation of sublimated sulfur in the furnace, liquid sulfur and pure oxygen enter the primary sulfur incinerator 3, including the heat recovery condensation device 14 gas phase outlet in step S4. Condensing gas, the ratio of the total amount of pure oxygen to the amount of liquid sulfur in the primary sulfur incinerator 3 is (1.1-1.3):1; in order to avoid excessively high temperature in a single furnace, the amount of sulfur sprayed in the primary sulfur incinerator 3 should be controlled to ensure that the liquid sulfur in the sulfur incinerator is fully burned while avoiding excessive furnace temperature to burn the sulfur gun and refractory bricks, and to reduce the gas concentration ratio of oxygen in the secondary sulfur incinerator 5 to ensure that the secondary sulfur incinerator 5 will not be overheated due to excessively high oxygen content in the furnace. Liquid sulfur and pure oxygen are set to enter the secondary sulfur incinerator 5, and the ratio of the total amount of pure oxygen to the amount of liquid sulfur in the secondary sulfur incinerator 5 is (1-1.1):1.

[0045] S2. Preparation of sulfur trioxide: The outlet gas of the secondary combustion heat recovery device 6 is mixed with the pure oxygen in the pure oxygen tank 2 in a volume ratio of (2.05-2.2): 1, and enters the first stage of the converter 7 to undergo a catalytic oxidation reaction of sulfur dioxide. The outlet gas of the first stage of the converter 7 enters the high-temperature heat recovery device 8 for heat exchange, and then enters the second stage of the converter 9 to undergo a second-stage catalytic oxidation reaction. The outlet gas of the second stage of the converter 9 enters the warm heat recovery device 10 for heat exchange again, and the outlet gas of the warm heat recovery device 10 enters the economizer 11 and the heat exchanger 12 in turn for heat exchange. In order to ensure that the composition and pressure of the system circulating gas remain in a relatively constant state, it is further necessary to control the excess of pure oxygen entering the first stage of the converter to ensure that the amount of liquid sulfur burned in the gas cycle of this section is the same as the amount of finished pure sulfur trioxide produced.

[0046] S3. Sulfur trioxide condensation and separation: The gas at the outlet of the heat exchanger 12 enters the compressor 13 for compression, the gas volume is reduced, and the temperature is increased. After the temperature is increased, the gas enters the heat recovery condensing device 14 for compressor mechanical heat energy recovery and condensation with the finished pure sulfur trioxide. The gas is separated into pure sulfur trioxide products in the heat recovery condensing device and enters the pure sulfur trioxide tank 16.

[0047] S4. Recover the non-condensable gas and enter the next cycle: the remaining uncondensed gas in the heat recovery condensation device 14 is used as non-condensable gas, and re-enters the primary sulfur incinerator 3 and the secondary sulfur incinerator 5 through the gas phase outlet pipe of the heat recovery condensation device 14, participates in the next cycle of the process system, and forms a gas phase closed circulation system. In order to ensure that the pressure lower than the external atmospheric pressure will not be formed in the system, in the process of gas circulation back to the sulfur incinerator, part of the uncondensed sulfur trioxide and unconverted sulfur dioxide are retained as non-condensable gas. This part of non-condensable gas plays the role of circulating gas and diluent gas. When returning to the sulfur incinerator, it can avoid that when pure oxygen is added to the furnace, its oxygen content is too high to form a high oxygen environment that damages the equipment in the furnace. In order to maintain the stability of the pressure and components of the gas circulation system, an exhaust gas discharge process is added on the way from the gas phase outlet pipe of the heat recovery condensation device 16 to the primary sulfur incinerator 3, and a small part of the non-condensable gas can be continuously or intermittently discharged to the exhaust gas absorption system 15 for treatment.

[0048] The present invention also provides a heat recovery process, including 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, and a coal economizer 11. The chemical heat energy in the device of the present invention is only the heat of sulfur combustion and the heat of sulfur dioxide oxidation, and the mechanical heat energy is the internal energy of the gas converted after the compressor does work on the process gas. These heats can be recovered through the thermal equipment set at the outlet of the sulfur incinerator, the outlets of each section of the converter, and the outlet of the compressor, so as to achieve efficient recovery and utilization of heat energy, increase the unit sulfur combustion steam production of the device, and reduce its own steam energy consumption.

[0049] Among them, in step S1, the first-level combustion heat recovery device 4 reduces the gas temperature to 650±20℃, and the sulfur dioxide gas still maintains a high reactivity at this temperature, which is conducive to the continued generation of sulfur dioxide and can also protect the equipment; the second-level combustion heat recovery device 6 reduces the gas temperature to 400±10℃, at this temperature, the catalytic reaction efficiency when entering the converter stage 7 can be guaranteed, and the catalyst deactivation due to excessive temperature can be avoided.

[0050] In step S2, after the outlet gas of the first stage converter 7 enters the high-temperature heat recovery device 8 for heat exchange, the gas temperature drops to 450±10°C, which is conducive to maintaining the stability of sulfur trioxide and avoiding side reactions at excessively high temperatures, ensuring that the gas still has high activity when entering the second stage converter 9.

[0051] In step S2, after the outlet gas of the second stage 9 of the converter enters the warm heat recovery device 10 for heat exchange again, the gas temperature drops to 200±10°C. This temperature adjustment is helpful for further energy recovery and optimization of the final condensation step.

[0052] In step S2, the outlet gas of the medium-temperature heat recovery device 10 enters the economizer 11 and the heat exchanger 12 in turn for heat exchange, and the gas temperature drops to 45-50° C. This is to ensure that the heat energy of the gas is fully utilized before entering the compressor and is reduced to a temperature suitable for the compressor to handle.

[0053] In step S3, the gas at the outlet of the heat exchanger 12 enters the compressor 13 and is compressed to 2-3 MPa, and the gas temperature reaches 200-250° C. The compressor parameter range is sufficient to ensure that the gas is effectively condensed into liquid sulfur trioxide in the subsequent condensation step, while also maximizing the use of the mechanical heat energy generated in the compressor process.

[0054] In order to recover the mechanical energy of the compressor, the cold side medium in the heat recovery condensing device 14 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.

[0055] In addition to being used in the working condition where a mixed gas of sulfur trioxide / sulfur dioxide is used as circulating gas, the present invention can also be used for:

[0056] 1. Sulfur dioxide / inert gas as circulating gas, such as Figure 1 As shown, inert gas (such as CO2 / He) and sulfur dioxide are used as the main components of the circulating gas from the heat recovery condensing device 14 to the primary sulfur incinerator and the secondary sulfur incinerator, which can reduce the oxygen concentration in the furnace and the sulfur trioxide concentration in each stage of the converter, and can also play a role in reducing the risk of overheating due to violent combustion of sulfur, and improve the sulfur dioxide conversion rate in the converter, and all the generated sulfur trioxide is extracted and separated as finished pure sulfur trioxide, and only the remaining sulfur dioxide and inert gas enter the next cycle, but this working condition may require larger equipment and pipelines for production at the same production capacity;

[0057] 2. Sulfur dioxide as circulating gas, such as Figure 1 As shown, using sulfur dioxide as the main component of the circulating gas from the heat recovery condensing device 14 to the primary sulfur incinerator 3 and the secondary sulfur incinerator 5 can reduce the oxygen concentration in the furnace, reduce the risk of overheating due to violent combustion of sulfur in the furnace, and increase the sulfur dioxide concentration in each stage of the converter, thereby promoting the forward conversion reaction; all the generated sulfur trioxide is extracted and separated as finished pure sulfur trioxide, and only the remaining sulfur dioxide enters the next cycle.

[0058] The sulfur trioxide product of the present invention is in liquid or critical gas state. The product is tested and the purity is 99.9%.

[0059] 1. Pure sulfur trioxide is prepared with pure oxygen. The process gas produced after the reaction, combustion and conversion of liquid sulfur and pure oxygen has low impurity content and no by-products such as nitrogen oxides. It can meet the conditions of direct output of liquid after compression and condensation. It gets rid of the constraint of the traditional sulfuric acid production process that the sulfur trioxide in the flue gas must be used to produce 98% sulfuric acid and oleum. The conversion rate of raw materials into pure sulfur trioxide products is extremely high, which can greatly expand the production capacity of pure sulfur trioxide;

[0060] 2. The present invention gets rid of the water replenishment process of the traditional sulfuric acid production process, avoids the waste of low-temperature heat from the reaction of SO3 and H20, and the chemical heat energy in the device is only the heat of sulfur combustion and the heat of sulfur dioxide oxidation. The mechanical heat energy is the internal energy of the gas converted after the compressor does work on the process gas. This heat can be recovered through the thermal equipment set at the outlet of the sulfur incinerator, the outlets of each section of the converter, and the outlet of the compressor, so as to achieve efficient recovery and utilization of heat energy, increase the unit sulfur combustion steam production of the device, and reduce its own steam energy consumption;

[0061] 3. Pure sulfur trioxide is produced by the sulfur dioxide / sulfur trioxide cycle process. Compared with the nitrogen component that accounts for about 80% in the traditional sulfuric acid plant, the total gas volume in the plant is smaller, which can reduce the scale of equipment and pipelines, and have a smaller footprint and construction consumables at the same capacity. It can also reduce the proportion of oxygen content in each sulfur incinerator, avoiding the high oxygen over-temperature environment that damages the equipment after pure oxygen is transported into the furnace.

[0062] 4. The present invention can take into account both production output and equipment life, and sets up two sulfur incinerators in series to burn liquid sulfur, which ensures the overall sulfur injection amount of the device while effectively controlling the temperature in the furnace through step-by-step combustion. After the first-level sulfur incinerator initially burns liquid sulfur to generate sulfur dioxide, it enters the first-level heat recovery device for cooling, reducing the heat load of the second-level sulfur incinerator. This staged treatment method helps to more accurately manage the temperature in each furnace, reduce the risk of equipment damage due to overheating, extend the life of the equipment, and ensure the stable operation of the device. At the same time, step-by-step combustion also improves energy utilization efficiency, helps to reduce unnecessary heat loss and equipment maintenance frequency, and improves overall production efficiency.

[0063] refer to Figures 3 to 8 In step S1, a filter assembly is connected to the outlet of the liquid sulfur tank 1, and the liquid sulfur in the liquid sulfur tank 1 enters the primary sulfur incinerator 3 and the secondary sulfur incinerator 5 through the filter assembly;

[0064] The filter assembly includes a filter box 17, a partition 19 is arranged in the filter box 17, and the partition 19 divides the filter box 17 into two filter chambers 21. The filter plates 18 are slidably arranged in the filter chambers 21. Two inclined plates 22 are arranged on the right side of the filter plate 18. The two inclined plates 22 are used to aggregate liquid sulfur. The inclined plates 22 are fixedly installed in the filter chamber 21. Two rotating rods 23 that are symmetrical up and down and front and back are arranged on the right side of the inclined plate 22. The rotating rod 23 is rotatably connected to the filter chamber 21, and a plurality of adsorption plates are fixedly arranged on the rotating rod 23. 33, a rotating shaft 30 is arranged on the right side of the rotating rod 23, and the rotating shaft 30 is rotatably connected with the filter chamber 21, and a plurality of adsorption strips 24 are fixedly arranged on the rotating shaft 30, and a rotating cylinder 32 is fixedly arranged on the other end of the plurality of adsorption strips 24, and a plurality of through grooves 31 are arranged on the rotating cylinder 32, and the through grooves 31 are staggeredly distributed with the adsorption strips 24, and the rotating cylinder 32 is in contact with the inner wall of the filter chamber 21, and a liquid outlet pipe 26 is also connected through the filter chamber 21, and the two liquid outlet pipes 26 are respectively connected with the primary sulfur incinerator 3 and the secondary sulfur incinerator 5 after being connected.

[0065] An L-shaped plate 28 is fixedly arranged on the right side of the filter box 17, a pressure sensor 27 is arranged on the L-shaped plate 28, a front-to-back symmetrical spring 29 is fixedly arranged on the L-shaped plate 28, the other end of the spring 29 is fixedly connected to a moving rod 25, the moving rod 25 slides and extends into the filter chamber 21, the moving rod 25 is fixedly connected to the filter plate 18, a groove is opened on the lower side wall of the filter box 17, and the moving rod 25 is slidably arranged in the groove;

[0066] The rotating rod 23 rotates upward and extends out of the filter box 17. The rotating rod 23 is set to be hollow. A plurality of air holes 34 are set on the rotating rod 23. The upper end of the rotating rod 23 is rotatably connected to a water pipe 43. The water pipe 43 is fixedly installed on the filter box 17. A connecting pipe 37 is connected to the water pipe 43. The other end of the connecting pipe 37 is connected to a water pump 35. The water pump 35 is fixedly installed on the filter box 17. The water pipe 43 is also connected to a front-to-back symmetrical cleaning pipe 41. The other end of the cleaning pipe 41 is connected to a spray pipe 38. Two openings are set on the upper side wall of the filter box 17. The spray pipe 38 is rotatably installed at the opening. An arc-shaped rack 49 is set on the spray pipe 38. A plurality of nozzles 50 are set on the spray pipe 38.

[0067] A liquid inlet hole is provided on the left side of the filter chamber 21, a slide plate 48 is slidably provided on the left side wall of the filter box 17, a liquid inlet pipe 47 is installed through the slide plate 48, a liquid storage box 20 is connected to the liquid inlet pipe 47, the liquid storage box 20 is fixedly connected to the slide plate 48, a lifting plate 46 is slidably provided in the liquid storage box 20, a linear drive member 51 is fixedly provided on the upper end of the liquid storage box 20, the lower output end of the linear drive member 51 slides and extends into the liquid storage box 20, the lower output end of the linear drive member 51 is fixedly connected to the lifting plate 46, a front-to-back symmetrical linear drive member 2 39 is provided on the filter box 17, the right output end of the linear drive member 2 39 is fixedly connected to the gear rod 42, the gear rod 42 is meshed with the arc-shaped rack 49, a linear drive member 3 40 is fixedly connected to the left side wall of the filter box 17, the output end of the linear drive member 3 40 is fixedly connected to the slide plate 48, and the linear drive member 3 40 is electrically connected to the pressure sensor;

[0068] A gear 1 52 and a sector gear 45 are fixedly provided on the rotating rod 23. The two gears 1 52 located on the same filter chamber 21 are meshed and connected. The two sector gears 45 located on the same filter chamber 21 are symmetrically distributed along the tangential direction of the meshing position of the two gears 1 52. A front-to-rear symmetrical tooth block 44 is slidably provided on the upper side wall of the filter box 17. The tooth block 44 is alternately meshed with the two sector gears 45. The rotating shaft 30 rotates upward and extends out of the filter box 17. A gear 2 36 is fixedly provided on the rotating shaft 30. The tooth block 44 is meshed and connected with the gear 2 36.

[0069] Liquid sulfur enters one of the filter chambers 21 through the liquid inlet pipe 47, is filtered by the filter plate 18, and then aggregated by the inclined plate 22. The liquid sulfur will impact the adsorption plate 33, and the impurities will be adsorbed on the adsorption plate 33, and at the same time, the rotating rod 23 will be driven to rotate. Then, the liquid sulfur enters the interior of the rotating cylinder 32 through the through groove 31, and then is adsorbed by a number of adsorption strips 24, and then discharged from the through groove 31, and then enters the primary sulfur incinerator 3 and the secondary sulfur incinerator 5 through 26;

[0070] Since the two rotating rods 23 on the same filter chamber 21 rotate in different directions, when the rotating rod 23 rotates, the rotating rod 23 drives the gear 1 52 to rotate, and the sector gear 45 also rotates together, and the sector gear 45 meshes with the tooth block 44 alternately, thereby driving the tooth block 44 to move back and forth, and the movement of the tooth block 44 drives the gear 2 36 to rotate, and the rotation of the gear 2 36 drives the rotating shaft 30 to rotate, and the rotating shaft 30 drives the rotating cylinder 32 to rotate, so that the sulfur in the rotating cylinder 32 can contact the adsorption strip 24 as much as possible, the adsorption effect is better, and the cleaning effect of the liquid sulfur is better;

[0071] After the filter plate 18 has filtered for a period of time, the holes on the filter plate 18 are blocked, that is, the filter chamber 21 needs to be cleaned. When liquid sulfur flows through again, the impact force will cause the filter plate 18 to move a longer distance to the right, and the filter plate 18 drives the moving rod 25 to move. At this time, the moving rod 25 will generate pressure on the pressure sensor 27. The pressure sensor 27 transmits the signal to the linear drive member 3 40, and the linear drive member 3 40 drives the slide plate 48 to move. The slide plate 48 drives the liquid storage box 20 to move to the liquid inlet hole position of the filter chamber 21 on the other side. During the movement, liquid sulfur continuously enters the liquid storage box 20. When the liquid inlet pipe 47 is aligned with the liquid inlet hole, the linear drive member 1 51 is started, and the lifting plate 46 moves downward to press the liquid sulfur in the liquid storage box 20 into the liquid inlet pipe 47.

[0072] Then, the liquid inlet pipe 47 is started, and the liquid inlet pipe 47 inputs water or cleaning liquid into the water pipe 43 through the connecting pipe 37 (two valves are arranged in the water pipe 43, which respectively control the water inlet of the upper two rotating rods 23 and the water inlet of the lower two rotating rods 23), and then discharged into the two rotating rods 23 in the filter chamber 21 to be cleaned, and then sprayed from the several air holes 34 on the rotating rods 23 to flush the filter plate 18 and the adsorption plate 33 and the several adsorption strips 24, so as to complete the cleaning. At the same time, the water or cleaning liquid will enter the ejection pipe 38 through the cleaning pipe 41. At this time, the linear drive member 2 39 on the filter chamber 21 to be cleaned is started, and the linear drive member 2 39 drives the gear rod 42 to move, and the gear rod 42 drives the arc-shaped rack 49 to rotate, and the arc-shaped rack 49 drives the ejection pipe 38 to rotate, so as to spray a larger range of the filter chamber 21 to be cleaned, and the cleaning effect is better and the cleaning speed is faster;

[0073] Through the filter plate 18, the plurality of adsorption plates 33 and the plurality of adsorption strips 24, the liquid sulfur can be effectively cleaned, and the cleaning effect is better. In addition, the rotation of the plurality of air holes 34, the plurality of nozzles 50 and the ejection pipe 38 can effectively clean the filter cavity 21 on the side to be cleaned, and the structural coordination is high and the practicability is strong.

[0074] Finally, it should be noted that the above-mentioned embodiments only express several implementation methods of the present invention and are not intended to limit the invention. For those skilled in the art, any modification, equivalent replacement, improvement, etc. made without departing from the concept of the present invention should be included in the protection scope of the invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A production process for preparing high-purity sulfur trioxide by high-efficiency pure oxygen using a two-stage conversion method with two furnaces in series, characterized in that: The following steps are involved: S1. Preparation of sulfur dioxide: Liquid sulfur in the liquid sulfur tank (1) and pure oxygen in the pure oxygen tank (2) enter the primary sulfur incinerator (3) and the secondary sulfur incinerator (5) for mixing, the liquid sulfur is fully burned in the furnace to generate sulfur dioxide, the outlet gas of the primary sulfur incinerator (3) enters the primary combustion heat recovery device (4) for cooling, and then enters the secondary sulfur incinerator (5) for mixing and burning with the liquid sulfur and pure oxygen that enter the secondary sulfur incinerator (5) separately, and the outlet gas of the secondary sulfur incinerator (5) enters the secondary combustion heat recovery device (6) for cooling; S2. Preparation of sulfur trioxide: The outlet gas of the secondary combustion heat recovery device (6) is mixed with the pure oxygen in the pure oxygen tank (2) and enters the first converter (7) to undergo a catalytic oxidation reaction of sulfur dioxide. The outlet gas of the first converter (7) enters the high-temperature heat recovery device (8) for heat exchange and then enters the second converter (9) for a second-stage catalytic oxidation reaction. The outlet gas of the second converter (9) enters the warm heat recovery device (10) for heat exchange again. The outlet gas of the warm heat recovery device (10) enters the economizer (11) and the heat exchanger (12) in sequence for heat exchange; S3. Sulfur trioxide condensation and separation: The gas at the outlet of the heat exchanger (12) enters the compressor (13) for compression, the gas volume is reduced, and the temperature is increased. After the temperature is increased, the gas enters the heat recovery condensation device (14) for compressor mechanical heat recovery and condensation of the finished pure sulfur trioxide. The gas is separated into pure sulfur trioxide products in the heat recovery condensation device and enters the pure sulfur trioxide tank (16); S4. Recover the non-condensable gas and enter the next cycle: the remaining uncondensed gas in the heat recovery condensation device (14) is treated as non-condensable gas and re-enters the primary sulfur incinerator (3) and the secondary sulfur incinerator (5) through the gas phase outlet pipeline of the heat recovery condensation device (14), and participates in the next cycle of the process system, forming a gas phase closed circulation system.

2. The production process for preparing high-purity sulfur trioxide by high-efficiency pure oxygen using a two-stage conversion method with two furnaces in series according to claim 1 is characterized in that: In step S1, liquid sulfur and pure oxygen enter the primary sulfur incinerator (3), including the non-condensable gas at the gas phase outlet of the heat recovery condensation device (14) in step S4, and the ratio of the total amount of pure oxygen in the primary sulfur incinerator (3) to the amount of liquid sulfur is (1.1-1.3):1; Liquid sulfur and pure oxygen enter the secondary sulfur incinerator (5), the ratio of the total amount of pure oxygen to the amount of liquid sulfur in the secondary sulfur incinerator (5) is (1-1.1):1, and the concentration of pure oxygen in the secondary sulfur incinerator (5) is lower than that in the primary sulfur incinerator (3).

3. The production process for preparing high-purity sulfur trioxide by high-efficiency pure oxygen using a two-stage conversion method with two furnaces in series according to claim 1 is characterized in that: In step S1, the primary combustion heat recovery device (4) reduces the gas temperature to 650±20°C; the secondary combustion heat recovery device (6) reduces the gas temperature to 400±10°C.

4. The production process for preparing high-purity sulfur trioxide by high-efficiency pure oxygen using a two-stage conversion method with two furnaces in series according to claim 1 is characterized in that: In step S2, the outlet gas of the secondary combustion heat recovery device (6) is mixed with pure oxygen in a volume ratio of (2.05-2.2):

1.

5. The production process for preparing high-purity sulfur trioxide by high-efficiency pure oxygen using a two-stage conversion method with two furnaces in series according to claim 1 is characterized in that: In step S2, the outlet gas of the first stage (7) of the converter enters the high-temperature heat recovery device (8) for heat exchange, and the gas temperature drops to 450±10°C.

6. The production process for preparing high-purity sulfur trioxide by high-efficiency pure oxygen using a two-stage conversion method with two furnaces in series according to claim 1 is characterized in that: In step S2, the outlet gas of the second stage (9) of the converter enters the warm heat recovery device (10) for heat exchange again, and the gas temperature drops to 200±10°C.

7. The production process for preparing high-purity sulfur trioxide by high-efficiency pure oxygen using a two-stage conversion method with two furnaces in series according to claim 1 is characterized in that: In step S2, the outlet gas of the medium-temperature heat recovery device (10) enters the economizer (11) and the heat exchanger (12) in sequence for heat exchange, and the gas temperature drops to 45-50°C.

8. The production process for preparing high-purity sulfur trioxide by high-efficiency pure oxygen using a two-stage conversion method with two furnaces in series according to claim 1 is characterized in that: In step S3, the gas at the outlet of the heat exchanger (12) enters the compressor (13) and is compressed to 2-3 MPa, and the gas temperature reaches 200-250°C.

9. The production process for preparing high-purity sulfur trioxide by high-efficiency pure oxygen using a two-stage conversion method with two furnaces in series according to claim 1, characterized in that: In step S4, an exhaust gas discharge process is added on the way from the gas phase outlet pipeline of the heat recovery condensing device (14) to the incinerator.

10. The production process for preparing high-purity sulfur trioxide by high-efficiency pure oxygen using a two-stage conversion method with two furnaces in series according to claim 9, characterized in that: A small portion of the non-condensable gas can be continuously or intermittently discharged to the tail gas absorption system (15) for treatment.

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