Device and method for preparing sodium pyrosulfite through one-step method

Abstract

The invention discloses a device and method for preparing sodium pyrosulfite through a one-step method, and belongs to the technical field of sodium pyrosulfite production. The problem that when three bubbling reaction kettles are used for continuously absorbing sulfur dioxide feed gas to produce sodium pyrosulfite, material transfer among the three reaction kettles is tedious is solved. The device specifically comprises a circulating absorption reactor, wherein a dynamic wave reactor is arranged in the circulating absorption reactor; the circulating absorption reactor is connected with the circulating absorption liquid preparation tank; the bottom of the circulating absorption reactor is connected with a centrifugal machine which is connected with the circulating absorption liquid preparation tank. According to the invention, alkali liquor is sprayed out from the large-diameter nozzle and then absorbs sulfur dioxide raw material gas in the dynamic wave reactor for reaction; according to the invention, sodium metabisulfite is added into the circulating absorption reactor to generate crystal mush containing sodium metabisulfite crystals, mother liquor obtained after the crystal mush is centrifuged can be conveyed into the circulating absorption liquid preparation tank to be prepared into alkali liquor again, and the reaction process only needs to be carried out in one circulating absorption reactor, so that material transfer among a plurality of reaction kettles is avoided, and the technological process is simplified.

Description

Technical Field

[0001] The invention relates to the technical field of sodium pyrosulfite production, and in particular to a device and method for preparing sodium pyrosulfite in one step. Background Art

[0002] Sodium metabisulfite, also known as sodium dithiosulfate or sodium pyrosulfate, is an inorganic compound. The current sodium metabisulfite production process generally uses three bubbling reactors to continuously absorb sulfur dioxide, and sodium metabisulfite crystals are precipitated when the pH is about 4 in the last reactor; the specific reaction process in the three bubbling reactors is:

[0003] Primary reactor: The purified SO2 gas is passed into the first bubbling reactor, and a soda solution is added for absorption. In this process, SO2 reacts with soda to generate sodium bisulfite and carbon dioxide. As the reaction proceeds, the concentration of sodium bisulfite gradually increases, and when it reaches a certain supersaturated concentration, sodium pyrosulfite crystals will precipitate.

[0004] Secondary reactor: The slurry in the primary reactor is continued to be passed into the second bubbling reactor for further reaction and crystallization. In this process, sodium bisulfite continues to react with SO2 to generate more sodium pyrosulfite crystals.

[0005] Three-stage reactor: The slurry in the second-stage reactor is passed into the third bubbling reactor for the final reaction and crystallization. By controlling the reaction conditions and slurry concentration, high-quality sodium metabisulfite products can be obtained.

[0006] Subsequent treatment: After the reaction and crystallization in three bubbling reactors, the obtained sodium metabisulfite slurry is centrifuged, dried and packaged to obtain the sodium metabisulfite product.

[0007] When using three bubbling reactors to produce sodium pyrosulfite, each reactor needs to be filled with sulfur dioxide gas of sufficient pressure to ensure the bubbling reaction. This process requires pressurization and has high energy consumption. In the prior art, the first and second bubbling reactors are also transformed into tower reactors to reduce the pressure of sulfur dioxide gas required in the reaction; however, this process and the process of producing sodium pyrosulfite using three bubbling reactors both involve the transfer of slurry between the three reactors, which is cumbersome to operate, has a long process flow, and the quality of the produced sodium pyrosulfite is unstable. Summary of the invention

[0008] In view of the deficiencies in the prior art, the present invention provides a one-step preparation device and method for sodium pyrosulfite, which solves the problems in the prior art of using three bubbling reactors to continuously absorb sulfur dioxide raw gas to produce sodium pyrosulfite, that the material transfer between the three reactors is cumbersome and the sulfur dioxide gas pressure requirement is high.

[0009] In the first aspect, in order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is:

[0010] A one-step sodium pyrosulfite preparation device comprises a circulating absorption reactor, a dynamic wave reactor, a circulating absorption liquid preparation tank and a centrifuge; a dynamic wave reactor is arranged in the circulating absorption reactor, a sulfur dioxide raw material gas inlet is connected to the top of the dynamic wave reactor, a large-diameter nozzle is arranged at the bottom of the dynamic wave reactor, the large-diameter nozzle is connected to the circulating absorption reactor through a slurry circulation pipe, and a slurry circulation pump is arranged on the slurry circulation pipe; an alkali liquid inlet of the circulating absorption reactor is connected to the circulating absorption liquid preparation tank through an alkali liquid pipe; the bottom of the circulating absorption reactor is connected to the centrifuge through a slurry circulation system, and the centrifuge is connected to the circulating absorption liquid preparation tank through a mother liquor circulation pipe.

[0011] In this scheme, the slurry circulation pump transports the alkali solution in the circulation absorption reactor to the large-diameter nozzle for spraying, so that it continuously absorbs the sulfur dioxide raw gas inside the dynamic wave reactor, so that the sulfur dioxide raw gas and the alkali solution fully react, which can reduce the pressure requirement for the sulfur dioxide raw gas and reduce energy consumption compared with the reaction in the bubbling reactor. A circulation absorption liquid configuration tank connected to the circulation absorption reactor is set up, and the mother liquor produced after centrifugation of sodium pyrosulfite crystals can be transported to the circulation absorption liquid configuration tank to be reconfigured into alkali solution, and then sent to the circulation absorption reactor through the alkali solution pipe for reaction again. The reaction process only needs to be carried out in one circulation absorption reactor, avoiding the transfer of materials between multiple reactors and simplifying the process flow.

[0012] Furthermore, the tail gas outlet at the top of the circulating absorption reactor is connected to one end of the tail gas pipe, and the other end of the tail gas pipe is connected to the tail gas absorption tower; a tail gas discharge port is provided at the top of the tail gas absorption tower, and the bottom of the tail gas absorption tower is connected to the circulating absorption liquid configuration tank through a tail gas absorption liquid pipe.

[0013] In this scheme, the sulfur dioxide in the tail gas can be absorbed by the tail gas absorption tower to reduce pollution to the environment; at the same time, the tail gas absorption liquid produced can be sent to the circulating absorption liquid preparation tank through the tail gas absorption liquid pipe to re-participate in the preparation of the alkali solution.

[0014] Furthermore, a demister is provided in the exhaust gas outlet.

[0015] In this solution, the demister is used to separate the mist from the exhaust gas.

[0016] Furthermore, the slurry circulation system includes a slurry circulation pipe; one end of the slurry circulation pipe is connected to the bottom of the circulation absorption reactor, and the other end of the slurry circulation pipe is connected to the middle of the circulation absorption reactor; a slurry circulation pump and a first valve are provided on the slurry circulation pipe;

[0017] The slurry circulation pipe is connected to one end of the slurry output pipe on the pipe body between the slurry circulation pump and the first valve, and the other end of the slurry output pipe is connected to the centrifuge; a second valve is arranged on the slurry output pipe.

[0018] In this scheme, at the initial stage of the reaction, the alkaline solution absorbs the sulfur dioxide raw gas to generate sodium sulfite, and the sodium sulfite is precipitated at the bottom of the circulating absorption reactor; the slurry circulation pump can transport the sodium sulfite precipitated at the bottom of the circulating absorption reactor to the middle of the circulating absorption reactor through the slurry circulation pipe, so that it continues to absorb the sulfur dioxide raw gas to generate sodium bisulfite, and finally the sodium bisulfite is self-dehydrated to obtain the sodium pyrosulfite product; the slurry circulation system can make the sodium sulfite continuously absorb the sulfur dioxide raw gas, so as to avoid the sodium sulfite formed at the beginning being precipitated at the bottom of the circulating absorption reactor.

[0019] Furthermore, a drying machine is provided at the discharge end of the centrifuge; the drying machine dries the sodium metabisulfite product after centrifugation.

[0020] Furthermore, the circulating absorption reactor is provided with a detection instrument; the detection instrument includes a pH sensor and a temperature sensor.

[0021] In this solution, the pH sensor is used to detect the pH of the reaction system inside the circulating absorption reactor, and the pH of the reaction system can reflect the reaction progress.

[0022] Furthermore, the circulating absorption liquid configuration tank is connected with an alkali solution inlet pipe.

[0023] In this scheme, alkali solution is added to the circulating absorption liquid preparation tank through the alkali solution inlet pipe.

[0024] In a second aspect, the present invention provides a method for preparing sodium pyrosulfite in one step based on the device for preparing sodium pyrosulfite in one step provided in the first aspect, comprising the following steps:

[0025] S1: injecting alkali solution into the circulating absorption reactor; introducing sulfur dioxide raw gas into the dynamic wave reactor;

[0026] S2: The alkali solution in the circulating absorption reactor is transported to the dynamic wave reactor, and the alkali solution and the sulfur dioxide raw gas react inside the dynamic wave reactor to generate a slurry containing sodium metabisulfite crystals and tail gas containing sulfur dioxide;

[0027] S3: transporting the slurry to a centrifuge for centrifugation, and transporting the mother liquor after centrifugation to a circulating absorption liquid preparation tank;

[0028] S4: The tail gas is transported to the tail gas absorption tower, the tail gas absorption tower absorbs the tail gas and then discharges it, and the tail gas absorption liquid generated after absorption is transported to the circulating absorption liquid configuration tank;

[0029] S5: adding sodium hydroxide solution into the circulating absorption liquid preparation tank to adjust the pH of the mother liquor and the tail gas absorption liquid to obtain new alkali solution;

[0030] S6: Send new alkali solution into the circulating absorption reactor through the alkali solution pipe to continue the reaction.

[0031] In this scheme, the slurry generated by the reaction of alkali solution and sulfur dioxide raw gas is centrifuged in a centrifuge to obtain sodium metabisulfite crystals and mother liquor. The mother liquor is transported to the circulating absorption liquid configuration tank to reconfigure the alkali solution to ensure that the part of sodium sulfite that has not precipitated in the mother liquor can return to the circulating absorption reactor to continue to participate in the reaction.

[0032] Furthermore, S2 includes:

[0033] S201: starting the slurry circulation pump, which transports the alkali solution to the dynamic wave reactor through the slurry circulation pipe and sprays it out from the large-diameter nozzle at the bottom of the dynamic wave reactor; the sprayed alkali solution and sulfur dioxide raw gas react inside the dynamic wave reactor to produce sodium sulfite and tail gas containing sulfur dioxide;

[0034] S202: Open the first valve and close the second valve; start the slurry circulation pump, which transports the sodium sulfite precipitated at the bottom of the circulation absorption reactor to the middle of the circulation absorption reactor through the slurry circulation pipe, so that the sodium sulfite continues to absorb the sulfur dioxide raw gas to produce sodium bisulfite;

[0035] S203: Sodium bisulfite is self-dehydrated to generate sodium pyrosulfite.

[0036] In this scheme, the slurry circulation pump drives the slurry to circulate in the slurry circulation pipe to ensure that the sodium sulfite can continuously absorb the sulfur dioxide raw gas to generate sodium bisulfite.

[0037] Furthermore, S3 includes:

[0038] S301: Detecting the pH of the reaction system inside the circulating absorption reactor; when the pH of the reaction system drops to 3.9-4.1, closing the first valve and opening the second valve, and transporting the slurry containing sodium metabisulfite crystals to the centrifuge through the slurry output pipe;

[0039] S302: centrifuging the slurry using a centrifuge to obtain sodium metabisulfite crystals and mother liquor;

[0040] S303: using a dryer to dry the sodium metabisulfite crystals to obtain a sodium metabisulfite product;

[0041] S304: The mother liquor after centrifugation is transported to the circulating absorption liquid preparation tank through the mother liquor circulation pipe.

[0042] The beneficial effects of the present invention are:

[0043] A dynamic wave reactor is arranged in the one-step sodium pyrosulfite preparation device provided by the present invention. After the alkali solution is sprayed into the dynamic wave reactor, the alkali solution absorbs the sulfur dioxide raw gas inside the dynamic wave reactor. The reaction mode has a lower pressure requirement for the sulfur dioxide raw gas. Compared with the mode of absorbing the sulfur dioxide raw gas inside the bubbling reactor in the prior art, the pressure requirement for the sulfur dioxide raw gas can be reduced, thereby reducing energy consumption.

[0044] The one-step sodium pyrosulfite preparation device provided by the present invention is provided with a circulating absorption liquid configuration tank, which is connected to a circulating absorption reactor through an alkali liquid pipe; the mother liquor generated when the sodium pyrosulfite crystals are centrifuged and the tail gas absorption liquid generated when the tail gas is absorbed can be reconfigured into alkali liquid in the circulating absorption liquid configuration tank, and then re-sent into the circulating absorption reactor through the alkali liquid pipe, so that the unprecipitated sodium sulfite contained in the mother liquor can react again; and the reaction process only needs to be carried out in one circulating absorption reactor, so that the material transfer between multiple reactors is avoided and the process flow is simplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic diagram of the structure of a device for preparing sodium pyrosulfite by a one-step method according to the present invention;

[0046] Figure 2 The present invention is a flow chart of a one-step method for preparing sodium pyrosulfite.

[0047] Reference numerals:

[0048] 1. Circulating absorption reactor; 10. Slurry circulation pump; 11. Slurry circulation pipe; 12. Alkali liquid inlet; 13. Alkali liquid pipe; 14. Tail gas pipe; 2. Power wave reactor; 21. Sulfur dioxide raw gas inlet; 22. Large-diameter nozzle; 3. Circulating absorption liquid configuration tank; 31. Mother liquid circulation pipe; 32. Alkali liquid inlet pipe; 33. Tail gas absorption liquid pipe; 4. Tail gas absorption tower; 5. Centrifuge; 6. Dryer; 7. Crystal slurry circulation pump; 71. Crystal slurry circulation pipe; 72. First valve; 73. Crystal slurry output pipe; 74. Second valve; 8. Testing instrument; 9. Demister; DETAILED DESCRIPTION

[0049] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. The specific implementation of the present invention is described below to facilitate the understanding of the present invention by those skilled in the art, but it should be clear that the present invention is not limited to the scope of the specific implementation. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

[0050] Example 1

[0051] like Figure 1 As shown, this embodiment provides a one-step method for preparing sodium pyrosulfite. When using the device to prepare sodium pyrosulfite, alkali liquid absorbs sulfur dioxide raw gas inside the dynamic wave reactor, and the gas pressure requirement for sulfur dioxide is relatively low; at the same time, it can replace the commonly used three-tower connection absorption process, reduce the process flow, and reduce energy consumption; it specifically includes:

[0052] Circulating absorption reactor 1, dynamic wave reactor 2, circulating absorption liquid preparation tank 3, tail gas absorption tower 4, centrifuge 5, drying machine 6, slurry circulation pump 7, detection instrument 8 and demister 9;

[0053] Among them, a dynamic wave reactor 2 is provided in the circulation absorption reactor 1, and a sulfur dioxide raw gas inlet 21 is connected to the top of the dynamic wave reactor 2. A large-diameter nozzle 22 is provided at the bottom of the dynamic wave reactor 2. The large-diameter nozzle 22 is connected to the circulation absorption reactor 1 through a slurry circulation pipe 11, and a slurry circulation pump 10 is provided on the slurry circulation pipe 11; the slurry circulation pump 10 transports the alkali solution in the circulation absorption reactor 1 to the large-diameter nozzle 22 for spraying, so that it continuously absorbs the sulfur dioxide raw gas inside the dynamic wave reactor 2, so that the sulfur dioxide raw gas and the alkali solution fully react.

[0054] The alkali liquid inlet 12 of the circulating absorption reactor 1 is connected to the circulating absorption liquid preparation tank 3 through the alkali liquid pipe 13; the bottom of the circulating absorption reactor 1 is connected to the centrifuge 5 through the slurry circulation system, and the centrifuge 5 is connected to the circulating absorption liquid preparation tank 3 through the mother liquid circulation pipe 31; the mother liquor generated after the centrifuge 5 centrifuges the sodium metabisulfite crystals can be transported to the circulating absorption liquid preparation tank 3 to be reconfigured into alkali liquid, and then sent to the circulating absorption reactor 1 through the alkali liquid pipe 13 to participate in the reaction again.

[0055] A dryer 6 is provided at the discharge end of the centrifuge 5 ; the dryer 6 dries the sodium metabisulfite product after centrifugation by the centrifuge 5 .

[0056] The tail gas outlet at the top of the circulating absorption reactor 1 is connected to one end of the tail gas pipe 14, and the other end of the tail gas pipe 14 is connected to the tail gas absorption tower 4. The top of the tail gas absorption tower 4 is provided with a tail gas discharge port. The tail gas absorption tower 4 can absorb sulfur dioxide in the tail gas to reduce pollution to the environment; the bottom of the tail gas absorption tower 4 is connected to the circulating absorption liquid configuration tank 3 through the tail gas absorption liquid pipe 33, and the generated tail gas absorption liquid can be sent to the circulating absorption liquid configuration tank 3 through the tail gas absorption liquid pipe 33 to re-participate in the configuration of the alkali solution.

[0057] A demister 9 is provided in the tail gas outlet, and the demister 9 is used to separate the mist in the tail gas.

[0058] The slurry circulation system includes a slurry circulation pipe 71 and a slurry output pipe 73; one end of the slurry circulation pipe 71 is connected to the bottom of the circulation absorption reactor 1, and the other end of the slurry circulation pipe 71 is connected to the middle of the circulation absorption reactor 1; a slurry circulation pump 7 and a first valve 72 are provided on the slurry circulation pipe 71; the slurry circulation pipe 71 is connected to one end of the slurry output pipe 73 on the pipe body located between the slurry circulation pump 7 and the first valve 72, and the other end of the slurry output pipe 73 is connected to the centrifuge 5; a second valve 74 is provided on the slurry output pipe 73. In the initial stage of the reaction, the alkali solution absorbs the sulfur dioxide raw gas to generate sodium sulfite, and the sodium sulfite is precipitated at the bottom of the circulating absorption reactor 1; the slurry circulation pump 7 can transport the sodium sulfite precipitated at the bottom of the circulating absorption reactor 1 to the middle of the circulating absorption reactor 1 through the slurry circulation pipe 71, so that it continues to absorb the sulfur dioxide raw gas to generate sodium bisulfite, and finally the sodium bisulfite is self-dehydrated to obtain the sodium pyrosulfite product; the slurry circulation system can make the sodium sulfite continuously absorb the sulfur dioxide raw gas, so as to avoid the sodium sulfite formed at the beginning being precipitated at the bottom of the circulating absorption reactor 1.

[0059] The circulating absorption reactor 1 is provided with a detection instrument 8, which includes a pH sensor and a temperature sensor. The pH sensor is used to detect the pH of the reaction system inside the circulating absorption reactor 1, and the pH of the reaction system can reflect the reaction process.

[0060] The circulating absorption liquid configuration tank 3 is connected to an alkali solution inlet pipe 32 ; alkali solution is added to the circulating absorption liquid configuration tank 3 through the alkali solution inlet pipe 32 .

[0061] Example 2

[0062] like Figure 2 As shown, this embodiment provides a one-step method for preparing sodium pyrosulfite based on the device for preparing sodium pyrosulfite in one step provided in Example 1, comprising the following steps:

[0063] S1: Alkali solution is prepared in the circulating absorption liquid preparation tank 3, and the alkali solution is transported to the circulating absorption reactor 1 through the alkali solution pipe 13;

[0064] Sulfur dioxide raw gas is introduced into the dynamic wave reactor 2 through the sulfur dioxide raw gas inlet 21 .

[0065] In this embodiment, the alkali solution is preferably a sodium hydroxide solution with a concentration of 22%-30%.

[0066] S2: transporting the alkali solution in the circulating absorption reactor 1 to the dynamic wave reactor 2, and reacting the alkali solution and the sulfur dioxide raw gas in the dynamic wave reactor 2 to produce a slurry containing sodium metabisulfite crystals and tail gas containing sulfur dioxide; specifically including:

[0067] S201: starting the slurry circulation pump 10, the slurry circulation pump 10 transports the alkali solution to the dynamic wave reactor 2 through the slurry circulation pipe 11, and sprays it out from the large-diameter nozzle 22 at the bottom of the dynamic wave reactor 2; the sprayed alkali solution and sulfur dioxide raw gas react inside the dynamic wave reactor 2 to produce a crystal slurry containing sodium sulfite and a tail gas containing sulfur dioxide;

[0068] S202: Open the first valve 72 and close the second valve 74; start the slurry circulation pump 7, which transports the sodium sulfite precipitated at the bottom of the circulation absorption reactor 1 to the middle of the circulation absorption reactor 1 through the slurry circulation pipe 71, so that the sodium sulfite is continuously circulated and continuously absorbs the sulfur dioxide raw gas to produce sodium bisulfite; ensure that the sodium sulfite can continuously absorb the sulfur dioxide raw gas to generate sodium bisulfite.

[0069] S203: Sodium bisulfite is self-dehydrated to generate sodium pyrosulfite.

[0070] S3: transporting the slurry containing sodium metabisulfite to the centrifuge 5 for centrifugation, and transporting the mother liquor after centrifugation to the circulating absorption liquid configuration tank 3; specifically comprising:

[0071] S301: Detecting the pH of the reaction system inside the circulating absorption reactor 1; when the pH of the reaction system drops to 3.9-4.1, closing the first valve 72 and opening the second valve 74, and transporting the slurry containing sodium metabisulfite crystals to the centrifuge 5 through the slurry output pipe 73;

[0072] S302: centrifuging the slurry using a centrifuge 5 to obtain sodium metabisulfite crystals and mother liquor;

[0073] S303: Drying the sodium metabisulfite crystals using a dryer 6 to obtain a sodium metabisulfite product;

[0074] S304: The mother liquid after centrifugation is transported to the circulating absorption liquid configuration tank 3 through the mother liquid circulation pipe 31 .

[0075] S4: The tail gas containing sulfur dioxide is transported to the tail gas absorption tower 4, and the tail gas absorption tower 4 absorbs the tail gas and then discharges it. The tail gas absorption liquid generated after the absorption is transported to the circulating absorption liquid configuration tank 3 through the tail gas absorption liquid pipe 33.

[0076] S5: adding sodium hydroxide solution into the circulating absorption liquid preparation tank 3 to adjust the pH of the mother liquid and the tail gas absorption liquid to obtain a new alkali solution; controlling the sodium ion concentration in the new alkali solution to be between 12.65% and 17.25%.

[0077] S6: Send new alkali solution into the circulation absorption reactor 1 through the alkali solution pipe 13 to continue the reaction.

[0078] Those skilled in the art will appreciate that the embodiments herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the invention.

Claims

1. A one-step method for preparing sodium pyrosulfite, characterized in that: The invention comprises a circulating absorption reactor (1), a dynamic wave reactor (2), a circulating absorption liquid preparation tank (3) and a centrifuge (5); the circulating absorption reactor (1) is provided with the dynamic wave reactor (2), the top of the dynamic wave reactor (2) is connected to a sulfur dioxide raw gas inlet (21), the bottom of the dynamic wave reactor (2) is provided with a large-diameter nozzle (22), the large-diameter nozzle (22) is connected to the circulating absorption reactor (1) through a slurry circulation pipe (11), and the slurry circulation pipe (11) is provided with a slurry circulation pump (10); the alkali liquid inlet (12) of the circulating absorption reactor (1) is connected to the circulating absorption liquid preparation tank (3) through an alkali liquid pipe (13); the bottom of the circulating absorption reactor (1) is connected to the centrifuge (5) through a slurry circulation system, and the centrifuge (5) is connected to the circulating absorption liquid preparation tank (3) through a mother liquid circulation pipe (31).

2. The device for preparing sodium pyrosulfite by one-step method according to claim 1, characterized in that: The tail gas outlet at the top of the circulating absorption reactor (1) is connected to one end of a tail gas pipe (14), and the other end of the tail gas pipe (14) is connected to a tail gas absorption tower (4); a tail gas discharge port is provided at the top of the tail gas absorption tower (4), and the bottom of the tail gas absorption tower (4) is connected to the circulating absorption liquid configuration tank (3) via a tail gas absorption liquid pipe (33).

3. The device for preparing sodium pyrosulfite by one-step method according to claim 2, characterized in that: A demister (9) is arranged in the tail gas outlet.

4. The device for preparing sodium pyrosulfite by one-step method according to claim 1, characterized in that: The slurry circulation system comprises a slurry circulation pipe (71); one end of the slurry circulation pipe (71) is connected to the bottom of the circulation absorption reactor (1), and the other end of the slurry circulation pipe (71) is connected to the middle of the circulation absorption reactor (1); a slurry circulation pump (7) and a first valve (72) are provided on the slurry circulation pipe (71); The slurry circulation pipe (71) is connected to one end of the slurry output pipe (73) on the pipe body located between the slurry circulation pump (7) and the first valve (72), and the other end of the slurry output pipe (73) is connected to the centrifuge (5); a second valve (74) is provided on the slurry output pipe (73).

5. The device for preparing sodium pyrosulfite by one-step method according to claim 1, characterized in that: A drying machine (6) is provided at the discharge end of the centrifuge (5); the drying machine (6) dries the sodium metabisulfite product after centrifugation in the centrifuge (5).

6. The device for preparing sodium pyrosulfite by one-step method according to claim 1, characterized in that: The circulating absorption reactor (1) is provided with a detection instrument (8); the detection instrument (8) comprises a pH sensor and a temperature sensor.

7. The device for preparing sodium pyrosulfite by one-step method according to claim 1, characterized in that: The circulating absorption liquid configuration tank (3) is connected to an alkali liquid inlet pipe (32).

8. A method for preparing sodium pyrosulfite in one step according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: injecting alkali solution into the circulating absorption reactor (1); Introducing sulfur dioxide raw gas into the dynamic wave reactor (2); S2: The alkali solution in the circulating absorption reactor (1) is transported to the dynamic wave reactor (2), and the alkali solution and the sulfur dioxide raw gas react inside the dynamic wave reactor (2) to generate a slurry containing sodium pyrosulfite crystals and tail gas containing sulfur dioxide; S3: transporting the slurry containing sodium metabisulfite crystals to a centrifuge (5) for centrifugation, and transporting the mother liquor after centrifugation to a circulating absorption liquid preparation tank (3); S4: transporting the tail gas containing sulfur dioxide to the tail gas absorption tower (4), the tail gas absorption tower (4) absorbs the tail gas and then discharges it, and the tail gas absorption liquid generated after the absorption is transported to the circulating absorption liquid configuration tank (3); S5: adding sodium hydroxide solution into the circulating absorption liquid preparation tank (3) to adjust the pH of the mother liquid and the tail gas absorption liquid to obtain new alkaline solution; S6: Send new alkali solution into the circulation absorption reactor (1) through the alkali solution pipe (13) to continue the reaction.

9. The method for the one-step method for preparing sodium pyrosulfite according to claim 8, characterized in that: The S2 includes: S201: starting the slurry circulation pump (10), the slurry circulation pump (10) transports the alkali solution to the dynamic wave reactor (2) through the slurry circulation pipe (11), and sprays it out from the large-diameter nozzle (22) at the bottom of the dynamic wave reactor (2); the sprayed alkali solution and the sulfur dioxide raw gas react inside the dynamic wave reactor (2) to produce sodium sulfite and tail gas containing sulfur dioxide; S202: opening the first valve (72) and closing the second valve (74); starting the slurry circulation pump (7), which transports the sodium sulfite precipitated at the bottom of the circulation absorption reactor (1) to the middle of the circulation absorption reactor (1) through the slurry circulation pipe (71), so that the sodium sulfite continues to absorb the sulfur dioxide raw gas to produce sodium bisulfite; S203: Sodium bisulfite is self-dehydrated to generate sodium pyrosulfite.

10. The method for preparing sodium pyrosulfite by one-step method according to claim 9, characterized in that: The S3 includes: S301: Detecting the pH of the reaction system inside the circulating absorption reactor (1); when the pH of the reaction system drops to 3.9 to 4.1, closing the first valve (72) and opening the second valve (74), and transporting the slurry containing sodium metabisulfite crystals to the centrifuge (5) through the slurry output pipe (73); S302: centrifuging the slurry using a centrifuge (5) to obtain sodium metabisulfite crystals and mother liquor; S303: using a dryer (6) to dry the sodium metabisulfite crystals to obtain a sodium metabisulfite product; S304: The mother liquid after centrifugation is transported to the circulating absorption liquid preparation tank (3) through the mother liquid circulation pipe (31).

Images