CN113274755B

CN113274755B - Process and device for preparing oxygen by phase thermal decomposition of sulfuric acid in iodine-sulfur cycle

Info

Publication number: CN113274755B
Application number: CN202110565904.9A
Authority: CN
Inventors: 刘宏; 董宏光; 王安然; 陈晓宇
Original assignee: Dalian University of Technology
Current assignee: Dalian University of Technology
Priority date: 2021-05-24
Filing date: 2021-05-24
Publication date: 2022-05-13
Anticipated expiration: 2041-05-24
Also published as: CN113274755A

Abstract

The invention provides an iodine-sulfur cycleA process and a device for preparing oxygen by phase thermal decomposition of cyclic sulfuric acid belong to the technical field related to hydrogen preparation by thermochemical cycle. The process comprises a sulfuric acid phase stripping purification section, a rectification concentration section, a water washing section, a sulfuric acid thermal decomposition and mixed gas regulation process and a device. The shell pass and the tube pass of the novel shell-and-tube heat integration composite tower are respectively filled with No. 1 and No. 2 fillers, N tower sections of the composite section are coaxially and hermetically connected, and a sulfuric acid phase stripping purification section, a reaction rectification section and a water washing section are coupled together, so that the energy gradient utilization is realized. The invention decomposes sulfuric acid into O-containing₂And SO₂And O produced by the system₂And the mixed gas is taken as stripping and purifying gas to enter a shell-pass stripping and purifying section of the composite tower and a HIX stripping and purifying tower respectively. Compared with the traditional process for preparing oxygen by sulfuric acid phase thermal decomposition, the process improves the quality and the energy utilization rate of the system, improves the purification efficiency and reduces the energy consumption and the production cost.

Description

Process and device for preparing oxygen by phase thermal decomposition of sulfuric acid in iodine-sulfur cycle

Technical Field

The invention relates to a process and a device for preparing oxygen by phase thermal decomposition of sulfuric acid in iodine-sulfur cycle hydrogen production, and belongs to the technical field related to iodine-sulfur thermochemical cycle hydrogen production.

Background

The major energy in the world today is fossil fuel, petroleum and natural gas are non-renewable energy sources and cause pollution to the environment, and the greenhouse effect is intensified by the emission of a large amount of CO2 from fossil fuel, so that the scientific community is seeking new energy sources without carbon. The hydrogen energy is high in energy density, clean and nontoxic, forms a plurality of compounds and has large reserves, and the hydrogen energy is considered as a future alternative energy carrier. However, conventional hydrogen production methods suffer from a number of disadvantages: CO produced in hydrogen production process by fossil fuel dry gas₂The discharge is large, the prepared hydrogen contains sulfur, and the high-purity hydrogen needs to be desulfurized and purified; the electrolytic hydrogen production process has low efficiency and higher cost; the hydrogen obtained by decomposing the biomass to prepare the hydrogen is limited, and cannot be applied to large-scale industry. Therefore, the development of a clean and pollution-free green hydrogen technology for preparing pure hydrogen on a large scale becomes a hot point of research.

At present, hydrogen production technologies reported in documents mainly include electrocatalytic water decomposition, solar water decomposition, biomass hydrogen production, direct thermal water decomposition, thermochemical cycle hydrogen production, and the like, and hydrogen production by thermochemical cycle is considered to be the most likely process for industrialization and large-scale application. Among the numerous thermochemical cycle pathways, JingmeiResearch reports of national GA, Japan atomic energy agency, Korea energy institute and French research institute that Iodine Sulfur (IS) thermochemical cycle IS clean H₂The main candidate for production. The Iodine Sulfur (IS) thermochemical cycle mainly comprises 3 reaction processes:

bunsen reaction-SO₂+I₂+2H₂O＝2HI+H₂SO₄ ⑴

SA sulfuric acid decomposition H₂SO₄＝H₂O+SO₂+1/2O₂ ⑵

HIX decomposition of hydrogen iodide 2HI ═ I₂+H₂ ⑶

Net reaction 2H₂O＝O₂+2H₂ ⑷

Wherein Bunsen is exothermic reaction, the reaction temperature is 120 ℃, the sulfuric acid decomposition reaction is endothermic reaction, the reaction temperature is 800-900 ℃, the hydrogen iodide decomposition is endothermic reaction, the reaction temperature is 300-500 ℃, and the net reaction product of the whole thermochemical cycle coupling system only contains H₂And O₂. The temperature of directly thermally decomposed water is reduced from 2500 ℃ to 800-900 ℃ in the iodine-sulfur thermal cycle hydrogen production process, and no CO is generated in the process₂And the clean hydrogen production process is expected to be produced in a large scale. In contrast, in the hydriodic acid unit after the Bunsen reaction, the hydriodic acid is doped with a small amount of H in the purification process₂SO₄The presence of impurities may, under certain conditions, cause the following side reactions:

formation of by-product S H₂SO₄+6HI＝S+3I₂+4H₂O ⑸

By-product H₂S generation H₂SO₄+8HI＝H₂S+4I₂+4H₂O ⑹

Although the IS cycle IS promising, there are many scientific and technical problems to be solved in order to realize large-scale production and industrialization. The traditional process for preparing oxygen by thermally decomposing sulfuric acid in iodine-sulfur cycle is complex, firstly, a stripping purification tank or a rectifying tower is generally used in an SA stripping purification section, and in addition, an SA rectifying concentration section and a stripping concentration sectionThe gas washing section needs 2 rectifying towers, wherein the steam stripping purification tower needs to consume energy, the high temperature of the SA rectifying concentration tower is difficult to be coupled with the steam stripping tower, the common rectifying tower structure cannot be solved, and the cascade utilization of energy cannot be realized. Secondly, if the traditional process for preparing oxygen by sulfuric acid phase thermal decomposition in iodine-sulfur cycle does not involve the process that an SA stripping section directly enters an SA rectification concentration section, a small amount of HI in a gas phase is brought into the SA rectification concentration section to influence the decomposition of sulfuric acid to generate O₂Of (2), partial HI is decomposed into H₂The energy consumption and the safety performance of the system are affected, if inert gas is used for steam stripping, byproducts are generated, and the cost of the system is increased; the traditional process HIX has no steam stripping section HIX directly entering HIX high pressure reactive distillation process, and small amount of SO in gas phase₂The introduction of HIX reaction rectification section has influence on the energy consumption and safety performance of HIX reaction system, if pure O is used₂Purification consumes the bulk acid HI, and if stripping is performed with an inert gas, byproducts are generated and the cost of the system increases. Finally, the recovery of acidic water from the conventional iodine-sulfur cycle sulfuric acid phase thermal decomposition oxygen generation process is inadequate, resulting in system I₂And SO₂The consumption of (c).

For SA Unit sulfuric acid phase purification and hydroiodic acid purification Process, China (reference 1)]Guo H F,Zhang P,Bai Y,et al.Continuous purification of H₂SO₄ and HI phases by packed column in IS process[J]International Journal of Hydrogen Energy,2010,35(7):2836-]Kubo S,Nakajima H,Kasahara S,et al.A demonstration study on a closed-cycle hydrogen production by the thermochemical water-splitting iodine-sulfur process.Nucl Eng Des[J]The purification method commonly used by countries such as Nuclear Engineering and Design,2004,233(1/3):347-354.) for the sulfuric and hydroiodic acid phases during IS cycles IS the reverse reaction using the Bunsen reaction: 2HI + H2SO4 ═ SO₂+I₂+2H₂And O is used for realizing two-phase purification, nitrogen is used as a purge gas, the reverse reaction of the Bunsen reaction is promoted to occur under the heating condition, and a small amount of hydroiodic acid in a sulfuric acid phase or a small amount of sulfuric acid in a hydroiodic acid phase is removed. The purification of the two phases by this process has the following disadvantagesOn one hand, the main acid such as sulfuric acid or hydroiodic acid is consumed, the hydrogen production rate is reduced, and on the other hand, a byproduct H is generated₂And S.

In order to eliminate the by-products of the sulphuric acid phase purification process, patent CN101857204B provides a process and a device for purifying the sulphuric acid phase in the iodine sulphur cycle at low pressure, which uses a low pressure purification process and a low pressure purification device, using the reverse reaction of the Bunsen reaction: 2HI + H₂SO₄＝SO₂+I₂+2H₂The sulfuric acid phase in the iodine-sulfur cycle is purified by using the O, the use of nitrogen is eliminated, and the defects of high cost of raw materials and equipment, complex process and the like caused by the use of nitrogen are overcome, but the purification efficiency in the process is low, and side reaction can be caused under certain conditions. Patent CN101857204B provides a method for purifying sulfuric acid phase, the sulfuric acid phase flows through a purification tower with controlled temperature under the condition of active purge gas purge, and a small amount of hydroiodic acid in the sulfuric acid phase and oxygen in the active purge gas undergo oxidation reaction to generate iodine: 4HI + O₂＝2I₂+2H₂O, for the purpose of purifying the sulfuric acid phase, but using a source of gas external to the system as purge gas, SA Unit O₂Recovery requires separation from the inert gas, increasing system costs.

In order to eliminate the by-products of the hydriodic acid purification process, japanese patent JP2008137824A provides a method for phase purification of hydriodic acid, which uses pure oxygen as a purge gas through the oxidation reaction: h₂SO4+H₂S+O₂＝2SO₂+2H₂O and S + O₂＝SO₂To eliminate H generated by side reaction in sulfuric acid phase and hydriodic acid phase₂And S. However, an excess of oxygen may cause deep oxidation of hydroiodic acid, thereby affecting the purification reaction. Patent CN101830443B provides a method for phase purification of hydroiodic acid using a mixture of oxygen and an inert gas as the active purge gas, but using a source of gas outside the system as the purge gas, SA unit O₂Recovery requires separation from the inert gas, increasing system costs.

Research on process for preparing oxygen by thermal phase decomposition of sulfuric acid in iodine-sulfur hydrogen production in currently-disclosed technical and literature dataCN103213945(A) provides a method for promoting the Bunsen reaction in thermochemical iodine-sulfur cycle hydrogen production, firstly I₂And H2O were added to the Bunsen reactor, a small amount of HI was added and stirred to dissolve iodine, and then SO was introduced₂The original gas-liquid-solid three-phase reaction is converted into the gas-liquid reaction, so that the dynamic rate of the Bunsen reaction is improved, only the strengthened Bunsen reaction is considered in the process, and excessive I required for phase separation after the Bunsen reaction is not considered₂Allowing the HI to react with H after the Bunsen reaction₂SO₄The phase separation is difficult, and the energy consumption for preparing oxygen by sulfuric acid phase thermal decomposition is increased; patent WO2008123651(a1) provides a method for separating and recovering pure SO at high temperature using absorption and degassing of ionic liquids₂The method is used for iodine-sulfur circulation, the ionic liquid is an ionic bonding compound and comprises acetate, sulfonate and the like, and the ionic liquid can influence the separation of the whole system if introduced into a Bunsen system circulation; patent US2013195749(a1) provides a method for improved thermochemical efficiency of nuclear power iodine-sulfur cycle hydrogen production, the concentration of sulfuric acid and the high temperature heat energy required in the decomposition process are supplied from a high temperature nuclear reactor, and since sulfuric acid has stronger hydrophilicity than hydrogen iodide, a large amount of water is generated in the phase separation absorption process after Bunsen reaction, and then introduced into a sulfuric acid concentrator, and high concentration of iodide is obtained only through the flash evaporation process, thereby reducing energy consumption and simplifying the process, thereby improving economic efficiency, and the patent is only an argument for the process, and does not mention related system equipment, and does not consider practical problems such as the application of acidic feed liquid; patent US20130330269(a1) provides a method for producing hydrogen from solar thermal energy coupled with an iodine-sulfur cycle, which only considers the source and coupling of energy and does not consider the industrial equipment and practical problems.

The iodine-sulfur circulation hydrogen production process has high hydrogen production efficiency and no CO₂The discharge is beneficial to carbon neutralization, so that the iodine-sulfur circulation is expected to become a clean, economic and sustainable large-scale hydrogen production method. The traditional process for preparing oxygen by thermally decomposing sulfuric acid in iodine-sulfur cycle is complex, a stripping purification tank or a rectifying tower is generally used in an SA stripping purification section, and in addition, 2 rectifying towers are needed in an SA rectifying concentration section and a stripping gas water washing section, wherein the stripping purification tower needs to consumeEnergy, the high temperature of the SA rectification concentration tower is difficult to couple with the stripping tower, and the common rectification tower structure cannot be solved, so that the cascade utilization of the energy cannot be realized. If the traditional process for preparing oxygen by sulfuric acid phase thermal decomposition in iodine-sulfur cycle does not involve the process that an SA stripping section directly enters an SA rectification concentration section, a small amount of HI in a gas phase is brought into the SA rectification concentration section to influence the decomposition of sulfuric acid to generate O₂Of (2), partial HI is decomposed into H₂The energy consumption and the safety performance of the system are affected, if inert gas is used for steam stripping, byproducts are generated, and the cost of the system is increased; the traditional process HIX has no steam stripping section HIX directly entering HIX high pressure reactive distillation process, and small amount of SO in gas phase₂The reaction is carried into HIX reaction rectification section, which affects the energy consumption and safety performance of HIX reaction system, if pure O is used₂Purification consumes the bulk acid HI, and if stripping is performed with an inert gas, byproducts are generated and the cost of the system increases. The recovery of acid water in the traditional oxygen preparation process by sulfuric acid phase thermal decomposition in the iodine-sulfur cycle is insufficient, resulting in system I₂And SO₂The consumption of (c).

Disclosure of Invention

The invention relates to a process and a device for preparing oxygen by thermal decomposition of sulfuric acid phase in iodine-sulfur cycle, and discloses a novel heat integration composite tower with a shell-and-tube structure, which strengthens the mass transfer and heat transfer processes, couples an SA steam stripping purification section, an SA rectification concentration section and a steam stripping gas washing section of the whole process together, integrates the heat of the SA rectification concentration section into the SA steam stripping purification section, and realizes the energy gradient utilization of the process and the system. The invention mixes the gas phase of the stripping tank and the extracted O₂The mixed gas is used as the steam purification gas, thereby avoiding using a gas source outside the system as the steam stripping gas, and improving SO in SA and HIX₂Recovery rate of (3), purification of S, H of SA inclusions₂S and a small amount of HI, so that S, H occluded by HIX series is purified₂S and a small amount of H₂SO₄. In addition, the invention returns the acidic water of the composite tower washing section extracted from the tower bottom of the composite tower C101 washing section to the mixing tank in front of the Bunsen reactor, thereby improving the quality and energy utilization rate of the system.

The specific technical scheme of the invention is as follows:

the invention relates to a process method for preparing oxygen by phase thermal decomposition of sulfuric acid in iodine-sulfur cycle, which is characterized by comprising the following steps: comprises an SA stripping purification section process, an SA rectification concentration section process, a heat integration composite tower washing section process and a sulfuric acid thermal decomposition and mixed gas regulation process.

And SA stripping and purifying section process: the SA feed from a post-separator of a Bunsen reactor enters a shell-side stripping purification section of a heat-integrated composite tower, gas blended by an SA unit serves as stripping gas of the shell-side stripping purification section of the composite tower, heat is provided by a tube-side rectification concentration section, liquid-phase SA feed of the stripping purification section is distributed by a gas-liquid distributor on a shell-side tray of the stripping purification section, liquid is uniformly distributed into packing of the shell-side stripping purification section of the tower section, sequentially contacts downwards for mass transfer through a plurality of stages of external connecting pipelines for communicating each tower section, and finally enters the shell-side rectification concentration section of the composite tower after being preheated by a heat exchanger; the gas phase of the stripping purification tower sequentially upwards contacts the liquid phase step by step through the shell-saving side of the composite tower and then passes through a compressor to reach the washing section of the composite tower;

the SA rectification concentration section process comprises the following steps: liquid phase of a rectification concentration section of the heat integration composite tower is uniformly distributed to a composite tower section tube side packing section through a top gas-liquid distributor liquid phase distribution pipe, the liquid phase of the rectification concentration section is heated into gas phase through a bottom reboiler and enters the tower section tube side packing section, the ascending gas phase and the descending liquid phase are sequentially contacted step by step, the gas phase at the top end of the rectification concentration section is condensed to a buffer tank through a condenser and is conveyed to the top of a composite tower washing section through an acidic washing water circulating pump to be used as washing water; sequentially contacting the downward liquid phase and the upward gas phase to the tower kettle of the rectification concentration section step by step, and extracting the circulating feed liquid at the bottom of the rectification concentration section tower;

the heat integration composite tower washing section process comprises the following steps: compressing stripping gas of a stripping purification section of the SA heat integration composite tower and stripping gas of an HIX stripping purification tower, then feeding the compressed stripping gas into a stripping gas washing section of the composite tower, washing the compressed stripping gas by using acidic water at the top of a sulfuric acid rectification concentration section of an SA unit composite tower, and extracting a product O at the top of a water washing section of the SA composite tower₂O coming out from the bottom of the water washing section of the composite tower₂Washing acidic water enters a mixing tank before Bunsen reaction;

the thermal decomposition and mixed gas conditioning of sulfuric acid and the process are as follows: heat integrationConcentrated sulfuric acid at the bottom of the condensation section of the combined tower enters a sulfuric acid thermal decomposition reactor through a feed pump and a feed preheater, decomposed mixed gas of the sulfuric acid thermal decomposition reactor enters a stripping gas storage tank, liquid phase of the stripping gas storage tank returns to the shell-side stripping purification section of the heat integration combined tower for feeding, and gas phase of the stripping gas storage tank and extracted O₂And the mixed gas is taken as stripping and purifying gas to enter a shell-pass stripping and purifying section of the composite tower and a HIX stripping and purifying tower respectively.

In the process, the heat integration composite tower utilizes the gas phase of the stripping tank and the extracted O₂The blended stripped purified gas was used to purify a small amount of HIX and some of the byproducts in the SA acid phase: a small amount of sulfuric acid undergoes the reverse reaction of the Bunsen reaction: 4HI + O₂＝2I₂+2H₂O；

Sulfuric acid and by-product H₂S is reacted: h₂SO₄+H₂S+O₂＝2SO₂+2H₂O；

The byproduct S reacts with the mixed gas: s + O₂＝SO₂，

S, H of mixed stripping gas and SA system after stripping and purifying section₂S and a small amount of HI to achieve the purpose of purifying HIX, and the mixed gas O is blended by the system₂Molar flow of and SO₂Has a molar flow ratio of more than 2: 3 and O₂The ratio of the molar flow of (b) to the molar flow of HI impurities contained in the SA system is greater than 1: 4;

HIX stripping purification column utilizes stripping tank gas phase and recovered O₂The blended stripped purified gas purifies a small amount of sulfuric acid and partial byproducts in HIX acid phase: a small amount of sulfuric acid undergoes the reverse reaction of the Bunsen reaction: h₂SO₄+2HI＝SO₂+I₂+2H₂O；

The byproduct S reacts with the mixed gas: s + O₂＝SO₂S, H of mixed stripping gas and HIX series of materials after stripping and purifying section₂S and a small amount of H₂SO₄Reacting to achieve the aim of purifying HIX, and mixing the mixed gas O by the system₂Molar flow of and SO₂The molar flow ratio of (a) is greater than 1: 2 and less than 2: 1.

A process unit for preparing oxygen by thermal decomposition of sulfuric acid in iodine-sulfur circulation comprises a heat integration composite tower, an HIX stripping purification tower, a sulfuric acid thermal decomposition reactor, a feed pump, an acidic washing water circulating pump, a stripping gas storage tank, an acidic washing water buffer tank, a composite tower tube-pass tower bottom reboiler, a composite tower sulfuric acid rectification section feed preheater, a composite tower sulfuric acid rectification section top condenser, a sulfuric acid decomposition reactor feed preheater and a compressor;

the heat integration composite tower comprises a stripping gas washing section, a shell-and-tube composite section tower section, an acidic washing water circulating pump, an acidic washing water buffer tank, a tube pass tower bottom reboiler, a sulfuric acid rectification section feeding preheater and a sulfuric acid rectification section top condenser;

the tower section of the heat integration composite section adopts a shell-and-tube structure, the shell pass of the heat integration composite section is communicated with the steam stripping purification section, the tube pass is communicated with the rectification concentration section, the tower section of each heat integration composite section is a single-stage theoretical stage, and the shell pass and the tube pass of the tower section of the heat integration composite section are respectively filled with fillers; n (N is more than or equal to 1) tower sections of the heat integration composite section are coaxially and hermetically connected; the heat integration composite section tower section comprises a rectification concentration section outer tower tray, a stripping purification section inner tower tray, a gas-liquid distributor, inner and outer tower tray sieve holes, a rectification concentration section tube nest, a composite tower section tower wall, a composite tower section flange, a stripping purification section liquid phase inlet and outlet, a stripping purification section vapor phase inlet and outlet and a tube shell pass bottom packing fixing plate;

the interior of the heat integration composite tower is divided into a heat integration composite section and a stripping gas washing section, and the heat integration composite section comprises a tube side rectification concentration section and a shell side stripping purification section; the shell side stripping purification section and the HIX stripping purification tower stripping gas enter the heat integration composite tower washing section after being pressurized by a compressor;

the shell of the tower section in the heat integration composite tower is formed by the tower wall of the composite tower section, the lower flange of the composite tower section and the upper flange of the composite tower section; the upper part of the composite tower section wall is provided with a shell pass stripping section tower section liquid feeding port and a stripping purification section tower section vapor outlet, the lower part of the composite tower section wall is provided with a stripping purification section tower section vapor inlet and a shell pass stripping section tower section liquid outlet, the shell pass stripping purification section tower section liquid feeding port is welded between a shell pass bottom filler fixing plate and a tube pass bottom filler fixing plate, the stripping purification section tower section vapor outlet is welded between an outer tower tray and an inner tower tray gas-liquid distributor liquid inlet, the stripping purification section tower section vapor inlet is welded at the upper part of the shell pass bottom filler fixing plate, and the shell pass stripping purification section tower section liquid outlet is welded between the outer tower tray and the inner tower tray;

two ends of the tube array of the tube pass rectification concentration section are respectively fixed on an outer tray of the rectification concentration section and a tube shell pass bottom packing fixing plate;

a steam stripping purification section inner tower tray, a rectification concentration section outer tower tray, a shell pass bottom packing fixing plate and a tube pass bottom packing fixing plate are fixed in the shell; the inner tray of the stripping purification section is fixed on the shell pass, and the outer tray of the rectification concentration section is fixed on the tube pass; holes are formed in the shell pass bottom filler fixing plate and the tube pass bottom filler fixing plate; sieve holes are arranged on the inner tower tray of the stripping purification section and the outer tower tray of the rectification concentration section, a gas-liquid distributor is welded in the sieve holes, and the aperture of each sieve hole is the same as the outer diameter of a liquid phase outlet of the gas-liquid distributor; the gas-liquid distributor is mainly formed by nesting a liquid phase pipe and a gas phase pipe, wherein the top of the gas phase pipe is used as a gas phase outlet, and the bottom of the gas phase pipe is used as a gas phase inlet; the top of the liquid phase pipe is used as a liquid phase inlet, and the bottom of the liquid phase pipe is used as a liquid phase outlet;

the tower sections are connected through flanges to form a heat integration composite section of the heat integration composite tower;

the top of the stripping gas water washing section of the heat integration composite tower is provided with O₂The side part of the extraction port is provided with acidic water H₂A washing acidic water extraction port is formed at the bottom of the feeding port O; the top of the shell side stripping purification section of the heat integration composite tower is provided with a stripping gas outlet of the stripping purification section of the heat integration composite tower, and the outlet is communicated with a gas inlet of the water washing section of the composite tower through a compressor in sequence by a pipeline; the upper part of the shell-side steam stripping purification section of the heat integration composite tower is provided with a liquid phase inlet, and the lower part of the shell-side steam stripping purification section of the heat integration composite tower is provided with a gas phase inlet and a liquid phase outlet; the liquid phase extraction outlet of the shell-side stripping purification section passes through the rectifying concentration section preheater and then is integrated with heatThe liquid phase inlets of the tube pass rectification concentration sections of the compound tower are connected; a liquid phase extraction outlet and a gas phase inlet are formed in the bottom of a tower kettle of a tube pass rectification concentration section of the heat integration composite tower, a pipeline from the liquid phase extraction outlet is divided into two paths, and one path enters from the gas phase inlet at the bottom of the tower kettle of the rectification concentration section after passing through a reboiler at the bottom of the tube pass tower of the composite tower; the other path enters the sulfuric acid decomposition reactor through a sulfuric acid decomposition reactor feed pump and a preheater;

HIX the upper part of the stripping and purifying tower is provided with a HIX material inlet, the bottom of the stripping and purifying tower is provided with a HIX purified liquid outlet, the bottom is provided with a stripping and purifying gas inlet, and the top is provided with a stripping and purifying gas outlet;

the stripping gas storage tank is provided with a gas inlet, a gas outlet and a discharge hole, the discharge hole is connected with a liquid phase feed inlet at the top of the stripping and purifying section of the composite tower, and the gas outlet is respectively connected with a gas phase inlet at the bottom of the stripping and purifying section of the composite tower and a gas phase inlet at the bottom of the stripping and purifying section of HIX.

The sulfuric acid decomposition reactor R101 is provided with a feed inlet and an air outlet, and the air outlet is connected with a gas phase air inlet of a stripping gas storage tank.

The total number of trays in the stripping section of the composite tower is N1, and N1 is more than or equal to 1; the total number of the outer trays of the rectifying and concentrating section is N2, and N2 is more than or equal to 1; external pipelines of the rectifying and concentrating sections of the shell-and-tube composite tower are connected step by step to form a symmetrical structure with the same theoretical stages of the rectifying and concentrating tower and the stripping and purifying tower, namely N1 is N2; the external pipeline of the rectifying and concentrating section of the composite tower is bridged to form an asymmetric structure with unequal theoretical stages of a rectifying and concentrating tower and a stripping and purifying tower, namely N1 is not equal to N2.

The total heat transfer area of the heat integration composite tower section is the sum of the wall surface heat transfer areas of a plurality of tube bundles in the composite section tower section, and the total heat transfer area is increased.

The outer diameter range of the heat integration shell-and-tube type composite tower is 100-8000 mm, the heat integration shell-and-tube type composite tower can be applied to various thermal coupling processes, and is not limited to a process for preparing oxygen through sulfuric acid phase thermal decomposition in iodine-sulfur circulation.

The pressure of the stripping and purifying section of the composite tower is controlled to be 1bar, and the temperature is 110-130 ℃; the tower pressure of the rectifying and concentrating section of the composite tower is controlled to be 1bar, the temperature of the top of the tower is 50-60, and the temperature of the bottom of the tower is 310-350 ℃; the tower pressure of the water washing section of the composite tower is controlled to be 5-7 bar, and the temperature is 110-130 ℃; HIX washing the tower with stripping gas, the tower pressure is controlled at 1bar, and the temperature is 110-130 deg.C.

The invention has the beneficial effects that: compared with the traditional process and device for preparing oxygen by thermally decomposing the sulfuric acid phase in the iodine-sulfur cyclic hydrogen production, the process and device for preparing oxygen by thermally decomposing the sulfuric acid phase in the iodine-sulfur cyclic hydrogen production strengthens the mass transfer and heat transfer processes by utilizing the novel shell-and-tube composite structure of the heat integration composite tower C101, couples the SA steam stripping purification section, the SA rectification concentration section and the steam stripping gas washing section of the whole process together, integrates the heat of the SA rectification concentration section into the SA steam stripping purification section, and realizes the energy conservation of the process and the system; the invention mixes the gas phase of the stripping tank and the extracted O₂The mixed gas is used as a steam purification gas, and the mixed gas O at the bottom of the steam stripping purification section of the SA compound tower₂Molar flow of and SO₂Has a molar flow ratio of more than 2: 3 and O₂The ratio of the molar flow of the second component to the molar flow of HI impurities contained in the SA system is more than 1: 4, SO that a gas source outside the system is prevented from being used as stripping gas, and SO in the SA is increased₂Recovery rate of (3), purification of S, H of SA inclusions₂S and a small amount of HI; the HIX stripping and purifying mixed gas O at the bottom of the tower₂Molar flow of and SO₂The molar flow ratio is more than 1: 2 and less than 2: 1, thereby avoiding using a gas source outside the system as stripping gas, and improving SO in HIX₂The recovery rate of (2) is high, and S, H of HIX series inclusion is purified₂S and a small amount of H₂SO₄. In addition, the acid water produced at the washing section of the composite tower from the bottom of the C101 water washing section of the composite tower returns to the mixing tank in front of the Bunsen reactor, so that the quality and the energy utilization rate of the system are improved, and the investment and the energy consumption can be reduced by more than 25 percent compared with the investment and the energy consumption of the traditional method for preparing oxygen by thermally decomposing sulfuric acid phase in the iodine-sulfur cyclic hydrogen production.

Drawings

FIG. 1 is a schematic diagram of a process apparatus for preparing oxygen by thermal phase decomposition of sulfuric acid in an iodine-sulfur cycle according to the present invention;

FIG. 2 is a schematic structural diagram of a heat-integrated composite tower for preparing oxygen by thermal decomposition of sulfuric acid in an iodine-sulfur cycle according to the present invention;

FIG. 3(a) is a schematic structural diagram of a tower section of a heat-integrated composite tower for preparing oxygen by thermal decomposition of sulfuric acid in iodine-sulfur cycle according to the present invention;

FIG. 3(b) is a schematic filling diagram of tower section packing of a heat integrated composite tower for preparing oxygen by thermal decomposition of sulfuric acid in iodine-sulfur cycle according to the present invention;

FIG. 4 is a schematic structural diagram of a tower section internal and external tray gas-liquid distributor of a heat integrated composite tower for preparing oxygen by thermal decomposition of sulfuric acid in iodine-sulfur circulation according to the present invention;

FIG. 5(a) is a schematic diagram of an external tower tray of a heat integrated composite tower for preparing oxygen by thermal decomposition of sulfuric acid in an iodine-sulfur cycle according to the present invention;

FIG. 5(b) is a schematic diagram of a tray in a tower section of a heat-integrated composite tower for preparing oxygen by the thermal decomposition of sulfuric acid in iodine-sulfur circulation according to the present invention;

in FIG. 1, S1-SA is fed; S2-SA composite tower stripping purification section tower bottom liquid; stripping a gas phase at the top of a purification section of the S3-SA composite tower; s4-stripping gas of a stripping tank; the bottom of a stripping and purifying section of the S51-SA composite tower is adjusted to be gas; S52-HIX stripping and purifying the bottom gas; s6-the bottom liquid of the sulfuric acid rectification concentration section of the compound tower; s7-decomposing the mixed gas by sulfuric acid; s8-stripping tank bottom feed liquid; s9-compound tower sulfuric acid rectification concentration section tower top produced water; S10-HIX stripping and purifying the mixed gas at the top of the tower; S11-O₂(ii) a S12-HIX; S13-HIX stripping the bottom liquid of the purification tower; o supplement by mixed gas at the bottom of stripping and purifying section of S14-SA composite tower₂(ii) a O is supplemented by mixed gas at the bottom of S15-HIX stripping and purifying tower₂(ii) a S16-acidic water of the washing section of the compound tower; C101-SA heat integration composite tower; C102-HIX stripping purification column; p101-charge pump; p102-acidic wash water circulation pump; v101-a stripping gas storage tank; v102-acid wash water buffer tank; e101-a reboiler at the bottom of the composite tower pipeline tower; e102-a feeding preheater of a sulfuric acid rectification concentration section of the compound tower; e103-a condenser at the top of the sulfuric acid rectification and concentration section of the compound tower; E104-R101 feed preheater; r101-sulfuric acid thermal decomposition reactor; d101, a compressor.

In FIG. 2, I-heat integration composite column stripping gas scrubbing section; II, a pipe shell type composite section of the heat integration composite tower; t1-first heat integrated composite tower shell and tube composite section tower section; t2-second heat integration composite tower tube shell composite section tower section; t3-third Heat setForming a composite tower pipe shell composite section tower section; t4-fourth heat integration composite tower shell-and-tube composite section tower section; l1-a pipeline connected with the external liquid of the shell-side stripping purification section of the first composite tower; l2-pipeline for connecting external liquid of shell-side stripping and purifying section of the second composite tower; l3-pipeline connected with external liquid of shell-side stripping and purifying section of the third composite tower; g1-pipeline connected with external gas of the shell pass stripping purification section of the third composite tower; g2-a second composite tower shell pass stripping purification section tower section external gas connection pipeline; g3-a first composite tower shell pass stripping purification section tower section external gas connection pipeline; p102-acidic wash water circulation pump; v102-acid wash water buffer tank; e101-a reboiler at the bottom of the composite tower pipeline tower; e102-a compound tower sulfuric acid rectifying section feed preheater; e103-a condenser at the top of the sulfuric acid rectifying section of the compound tower; S1-SA feed; stripping and purifying section tower bottom liquid by an S2-SA composite tower; stripping a gas phase at the top of a purification section of the S3-SA composite tower; stripping mixed gas at the bottom of a purification section of the S51-SA composite tower; s6-material liquid at the bottom of the sulfuric acid rectifying section of the compound tower; s9-the water is extracted from the top of the sulfuric acid rectifying section of the compound tower; S10-HIX stripping and purifying the mixed gas at the top of the tower; S11-O₂(ii) a S16-composite tower wash stage sour water.

In FIG. 3(a), 1-rectifying concentrating section external tray; 2-tower tray sieve holes; 3-shell side steam stripping purification section tower section liquid feed inlet; 4-stripping purification section internal tray; 5-rectifying and concentrating section tube array; 6-composite tower section tower wall; 7-steam stripping purification section tower gas saving phase inlet; 8-the lower flange surface of the composite tower section; 9-outer tray gas-liquid distributor; 10-upper flange surface of the composite tower section; 11-outer tray gas-liquid distributor liquid inlet; 12-a steam-saving phase outlet of a stripping purification section tower; 13-gas outlet of gas-liquid distributor of inner tower tray; 14-inner tray gas-liquid distributor; 15-shell side; 16-shell side bottom packing fixed plate liquid channel; 17-shell pass bottom packing fixing plate; 18-shell side steam stripping purification section tower section liquid discharge port; 19-tube pass bottom packing fixing plate.

In FIG. 3(b), the column packing of the 1# -shell side stripping purification section; and 2# -tube pass rectification concentration section tower section packing.

In FIG. 4, A-gas-liquid distributor liquid phase inlet; b-a liquid phase outlet of the gas-liquid distributor; c-gas phase outlet of gas-liquid distributor; d-gas-liquid distributor gas phase pipe; e-gas phase inlet of gas-liquid distributor; f-gas liquid phase pipe of gas-liquid distributor.

In FIG. 5(a), T1-1-composite column section stripping purification section external tray; t1-2-composite tower section stripping purification section outer tray sieve holes.

In FIG. 5(b), T2-1-composite tower section rectification concentration section inner tray; t2-2-composite tower section inner tray sieve holes; t2-3-composite tower section inner tray fixed welding mouth.

Detailed Description

The technical scheme of the invention is described in detail below with reference to the accompanying drawings and specific examples, which are only used for explaining the invention, but the protective scope of the invention is not limited to the examples.

The invention relates to a process and a device (figure 1) for preparing oxygen by thermal decomposition of sulfuric acid in iodine-sulfur circulation, wherein the process and the device comprise SA heat integration composite towers C101 and HIX, a stripping purification tower C102, an R101 feed pump P101, an acidic washing water circulating pump P102, a stripping gas storage tank V101, an acidic washing water buffer tank V102, a composite tower tube bottom reboiler E101, a composite tower sulfuric acid rectification section feed preheater E102, a composite tower sulfuric acid rectification section top condenser E103, an R101 feed preheater E104, a sulfuric acid thermal decomposition reactor R101 and a compressor D101.

The feed of the SA heat integration composite tower C101 shell side stripping purification section is SA feed S1 and feed liquid S8 at the bottom of the stripping tower, the feed liquid S2 at the bottom of the SA composite tower stripping purification section is heated by a composite tower sulfuric acid rectification concentration section feed preheater E102 and then enters a C101 tube side rectification concentration section, the gas phase S3 at the top of the SA composite tower stripping purification section and the mixed gas S10 at the top of the HIX stripping purification section from the HIX stripping purification tower C102 are compressed by a compressor D101 and then enter a C101 heat integration composite tower stripping gas washing section, and the product discharge O9 is washed by the composite tower sulfuric acid rectification concentration section tower top produced water S9₂The acid water S16 is extracted from the bottom of the stripping gas washing section of the composite tower through an S11 pipeline.

The gas phase at the top of the C101 tube pass rectification concentration section of the SA heat integration composite tower passes through a condenser E103 at the top of the sulfuric acid rectification section of the composite tower to be buffered by acidic washing waterAnd a tank V102 is used as washing water at the top of the washing section of the compound tower through an acid washing water circulating pump P102, and water washing is carried out on the gas phase S3 at the top of the stripping and purifying section of the SA compound tower and the gas phase S10 at the top of the stripping and purifying section of the SA compound tower. Concentrated sulfuric acid at the bottom of the concentration section of the compound tower enters a sulfuric acid thermal decomposition reactor R101 after being heated by a sulfuric acid thermal decomposition reactor R101 feeding pump P101 through a R101 feeding preheater E104, decomposed mixed gas of the R101 enters a stripping gas storage tank V101, feed liquid S8 at the bottom of a stripping tank returns to the feeding of a shell side stripping purification section of the SA thermal integration compound tower C101, feed liquid S8 at the bottom of the stripping tank and mixed gas at the bottom of the stripping purification section of the S14 compound tower supplement O₂The mixed gas is taken as SA composite tower stripping purification section tower bottom mixed gas S51 to enter a composite tower C101 shell side stripping purification section, and the stripping tank bottom feed liquid S8 is mixed with S15HIX stripping purification tower bottom mixed gas to supplement O2 and then taken as HIX stripping purification tower bottom mixed gas S52 to enter a HIX stripping purification tower C102.

HIX stripping purification column C102 feed is HIX feed S12 separated after Bunsen reaction, HIX feed contains HI, H₂O、I₂And small amounts of SO₂Jing O₂After the blended HIX steam stripping purification tower bottom gas adjustment and the gas S52 steam stripping purification, HIX steam stripping purification tower bottom liquid S13 enters a HIX high-pressure reaction rectification unit, and HIX steam stripping purification tower top mixed gas S10 enters a C101 composite tower steam stripping gas washing section to be washed and extracted O₂。

A heat integration composite tower for preparing oxygen by thermal decomposition of sulfuric acid in iodine-sulfur circulation is shown in figure 2 and comprises an SA heat integration composite tower C101, an acidic washing water circulating pump P102, an acidic washing water buffer tank V102, a composite tower tube-pass tower bottom reboiler E101, a composite tower sulfuric acid rectifying section feeding preheater E102 and a composite tower sulfuric acid rectifying section top condenser E103;

an SA heat-integration composite tower C101 for preparing oxygen by thermally decomposing sulfuric acid phase in iodine-sulfur circulation comprises a heat-integration composite tower stripping gas washing section I and a heat-integration composite tower shell-and-tube composite section II, wherein the heat-integration composite section consists of a stripping purification section and a rectification concentration section. The heat integration composite section tower adopts a shell-and-tube composite structure, the shell side of the heat integration composite section is communicated with the steam stripping purification section, the tube side is communicated with the rectification concentration section, each composite section tower section is a single-stage theoretical stage, the shell side and the tube side of the composite section tower section are respectively filled with 1# and 2# fillers, and N (N is more than or equal to 1) tower sections of the heat integration composite section tower section are coaxially and hermetically connected. The stripping gas washing section of the heat integration composite tower consists of a buffer tank, a common plate tower, a gas phase distributor and a circulating pump.

The connection relation of N (N is more than or equal to 1) tower sections of the pipe shell type composite section of the heat integration composite tower is as follows (figure 2): the adjacent heat integration tower sections are coaxially and hermetically connected through flanges, the liquid phase of a stripping purification section is SA feeding S1 separated by a Bunsen reaction, the liquid is uniformly distributed to a tower section shell side stripping purification section filler through the distribution of a gas-liquid distributor on a shell side tower tray of the stripping purification section, the liquid is connected with a pipeline L1 through an external liquid phase of a tower section of a first composite tower shell side stripping purification section to a tower tray feeding port of a pipe shell composite section T2 of a second heat integration composite tower, the liquid phase of a tower section T2 of the second heat integration composite tower shell side stripping purification section is connected with a pipeline L2 through a liquid phase outlet of a pipe shell composite section T2 of the second heat integration composite tower to a tower section feeding port of a pipe shell composite section T3 of the third heat integration composite tower, the liquid phase of a tower section T3 of the pipe shell composite tower is connected with an external liquid phase outlet of a tower section of the third composite tower shell side stripping section L3 through a feeding port of a pipe shell composite tower 4 of the fourth heat integration composite tower, the feed liquid S2 at the bottom of the SA composite tower stripping purification section is heated by a composite tower sulfuric acid rectification section feed preheater E102 and then enters a thermal integration composite tower sulfuric acid rectification concentration section;

the gas phase of the stripping and purifying section passes through a fourth heat integration composite tower tube shell composite section tower section T4 outlet third composite tower shell section external gas connecting pipeline G1 to the shell section of a third heat integration composite tower tube shell composite section tower section T3, passes through a third heat integration composite tower tube shell composite section tower section T3 outlet second composite tower shell section stripping and purifying section tower section external gas connecting pipeline G2 to the shell section of a second heat integration composite tower tube shell composite section tower T2, passes through a second heat integration composite tower tube shell composite section tower section T2 outlet first composite tower shell section external gas connecting pipeline G3 to the shell section of a first heat integration composite tower tube shell composite section tower T1, and passes through an SA composite tower stripping and purifying tower top section gas phase S3 pipeline to pass through a compressor to a C101 composite tower stripping gas washing section;

liquid phase of the rectification concentration section is uniformly distributed through a top gas-liquid distributor liquid phase distribution pipe F and then is sent to a first heat integration composite tower tube shell composite section tower section T1 tube side filling section, liquid phase of a superior rectification concentration section is uniformly distributed through a top gas-liquid distributor liquid phase distribution pipe F and then is sent to a second heat integration composite tower tube shell composite section tower section T2 tube side filling section, liquid phase of a superior rectification concentration section is uniformly distributed through a top gas-liquid distributor liquid phase distribution pipe F and then is sent to a third heat integration composite tower tube shell composite section tower section T3 tube side filling section, liquid phase of a superior rectification concentration section is uniformly distributed through a top gas-liquid distributor liquid phase distribution pipe F and then is sent to a fourth heat integration composite tower tube shell composite section tower section T4 tower section tube side filling section, liquid phase of a fourth heat integration composite tube shell tower composite section tower bottom tower T4 rectification concentration section tower bottom liquid phase enters a heat integration composite tower C101 rectification concentration section tower kettle, and liquid material liquid S6 of a composite tower sulfuric acid section is collected;

the liquid phase of the rectification concentration section is heated by a reboiler E101 at the bottom of the composite tower tube pass tower to rise to a tower section T4 tube pass filler section of a fourth heat integration composite tower tube shell composite section, is distributed by a gas-liquid distributor gas-phase distribution pipe D at the top and then uniformly rises to a tower section T3 tube pass filler section of a third heat integration composite tower tube shell composite section, is distributed by the gas-liquid distributor gas-phase distribution pipe D at the top and then uniformly rises to a tower section T2 tube pass filler section of a second heat integration composite tower tube shell composite section, is distributed by the gas-liquid distributor gas-phase distribution pipe D at the top and then uniformly rises to a tower section T1 tube pass filler section of a first heat integration composite tower tube shell composite section, the gas phase at the top end of the rectification concentration section passes through a condenser E103 at the top of a sulfuric acid rectification section of the composite tower to a stripping gas storage tank V102, and is used as washing water at the top of the composite tower washing section by an acid washing water circulating pump P102, and (3) stripping the gas phase S3 at the top of the SA composite tower stripping purification section and O in the mixed gas S10 at the top of the SA composite tower stripping purification section HIX stripping purification.₂External SO₂Washing with other components, and taking out the acidic water S16 from the washing section of the composite tower to a mixing tank before Bunsen reaction.

The structure of the heat integration composite section tower section is shown in fig. 3(a) and 3 (b): the heat integration composite section tower section adopts a shell-and-tube structure and comprises a rectifying and concentrating section outer tower tray 1, a stripping and purifying section inner tower tray 4, an outer tower tray gas-liquid distributor 9, an inner tower tray gas-liquid distributor 14, tower tray sieve holes 2, a rectifying and concentrating section tube array 5, a composite tower section tower wall 6, connecting

flanges

8 and 10 at the two side ends of the tower section, a shell side stripping and purifying section tower section liquid feeding port 3, a shell side stripping and purifying section tower section liquid discharging port 18, a stripping and purifying section tower section vapor phase inlet 7, a stripping and purifying section tower vapor phase outlet 12, a shell side bottom filler fixing plate 17 and a tube side bottom filler fixing plate 19. The composite section tower section is welded and fixed through an inner tower tray, an outer tower tray and a tube pass bottom packing fixing plate which are nested inside, the upper ends of the inner tower tray and the outer tower tray are hermetically welded with a gas-liquid distributor, and shell pass stripping purification section tower section 1# packing and tube pass rectifying concentration section tower section 2# packing are arranged between the inner tower tray, the outer tower tray and the bottom fixing plate. The shell of the tower section in the heat integration composite tower is formed by the tower wall of the composite tower section, the lower flange of the composite tower section and the upper flange of the composite tower section; the upper part of the composite tower section wall is provided with a shell pass stripping section tower section liquid feeding port and a stripping purification section tower section vapor outlet, the lower part of the composite tower section wall is provided with a stripping purification section tower section vapor inlet and a shell pass stripping section tower section liquid outlet, the shell pass stripping purification section tower section liquid feeding port is welded between a shell pass bottom filler fixing plate and a tube pass bottom filler fixing plate, the stripping purification section tower section vapor outlet is welded between an outer tower tray and an inner tower tray gas-liquid distributor liquid inlet, the stripping purification section tower section vapor inlet is welded at the upper part of the shell pass bottom filler fixing plate, and the shell pass stripping purification section tower section liquid outlet is welded between the outer tower tray and the inner tower tray; two ends of the tube array of the tube pass rectification concentration section are respectively fixed on an outer tray of the rectification concentration section and a tube shell pass bottom packing fixing plate; a stripping purification section inner tower tray, a rectification concentration section outer tower tray, a shell side bottom filler fixing plate and a tube side bottom filler fixing plate are fixed in the shell; the inner tray of the stripping purification section is fixed on the shell pass, and the outer tray of the rectification concentration section is fixed on the tube pass; holes are formed in the shell pass bottom filler fixing plate and the tube pass bottom filler fixing plate; the tower sections are connected through flanges to form a heat integration composite section of the heat integration composite tower;

the structure (figure 4) of the gas-liquid distributor of the inner tower tray and the outer tower tray of the heat integration composite section tower section comprises a liquid-phase inlet A of the gas-liquid distributor, a liquid-phase outlet B of the gas-liquid distributor, a gas-phase outlet C of the liquid distributor, a gas-phase pipe D of the gas-liquid distributor, a gas-phase inlet E of the gas-liquid distributor and a liquid-phase pipe F of the gas-liquid distributor, wherein the gas-liquid distributor is welded in sieve pores of the inner tower tray and the outer tower tray, and the aperture of the sieve pores is the same as the outer diameter of the liquid-phase outlet of the gas-liquid distributor; the gas-liquid distributor is mainly formed by nesting a liquid phase pipe and a gas phase pipe, wherein the top of the gas phase pipe is used as a gas phase outlet, and the bottom of the gas phase pipe is used as a gas phase inlet; the top of the liquid phase pipe is used as a liquid phase inlet, the bottom of the liquid phase pipe is used as a liquid phase outlet, and the gas-liquid distributors arranged on the inner tower tray and the outer tower tray enable the distribution of vapor and liquid to be averaged in the mass transfer process, so that the mass transfer area is increased.

The heat integrated composite section tower section inner and outer tray structure comprises a rectification concentration section outer tray structure and a stripping purification section inner tray structure, the rectification concentration section outer tray structure is shown in figure 5(a), the outer tray is provided with a sieve hole T1-2, and the rectification concentration column pipe is connected between the rectification concentration section outer tray and the bottom fixing plate in a sealing and communicating mode. FIG. 5(b) is the structure of the inner tray of the stripping and purifying section, the inner tray is provided with a sieve hole T2-2 and a fixed welding port T2-3 of the inner tray of the composite tower section, and the upper ends of the inner and outer trays are hermetically welded with the gas-liquid distributor.

The composite section tower section is welded and fixed by an inner tower tray, an outer tower tray and a tube shell pass bottom packing fixing plate which are nested inside. FIG. 5(a) is a structure of an outer tray of the rectifying and concentrating section, wherein the outer tray is provided with a sieve hole T1-2, and the outer tray of the rectifying and concentrating section is communicated with a bottom fixing plate in a sealing manner to be connected with a rectifying and concentrating tube. Fig. 5(b) is a structure of an inner tray of a stripping purification section, a sieve hole T2-2 is arranged on the inner tray, and a fixed welding port T2-3 of the inner tray of a composite tower section is arranged on the inner tray, the upper ends of the inner tray and the outer tray are hermetically welded with a gas-liquid distributor, a shell-side stripping purification section 1# filler and a tube-side rectification concentration section 2# filler are arranged between the inner tray, the outer tray and a bottom fixing plate, and the gas-liquid distributor arranged on the inner tray and the outer tray makes the distribution of vapor and liquid in the mass transfer process uniform, thereby increasing the mass transfer area.

The process for preparing oxygen by carrying out sulfuric acid phase thermal decomposition in iodine-sulfur circulation by adopting the device comprises the following steps:

and SA stripping and purifying section process: SA feed S1 from a separator at the back of the Bunsen reactor enters a shell-side stripping and purifying section of a C101 heat integration composite tower, and the bottom of the shell-side stripping and purifying section of the SA composite tower contains SO₂And O₂The mixed gas S51 is used as stripping gas in the stripping and purifying section of the composite tower, heat is provided in the tube pass rectifying and concentrating section, and stripping and purifying are carried outLiquid phase SA feed of the section is distributed through a gas-liquid distributor on a shell pass tray of a stripping purification section, liquid is uniformly distributed into a packing of the stripping purification section of the tower section shell pass, the liquid phase of the outer part of the tower section of the second composite tower shell-stripping purification section is connected with a feed port of an inner tower disc through a first composite tower shell-stripping purification section tower section L1 to a second heat integration composite tower shell-stripping section tower section T2, and is connected with a liquid phase outlet through a second heat integration composite tower shell-stripping purification section tower section T2, and is connected with a pipe L2 to a feed port of a third heat integration composite tower shell-stripping purification section tower section T3, and is connected with a pipe L3 to a feed port of a fourth heat integration composite tower shell-stripping purification section tower section T4 through a third heat integration composite tower shell-stripping section T3 tower section liquid phase outlet, and is preheated by a composite tower sulfuric acid rectification section feed pipe shell preheater E102 and then enters a composite tower shell-stripping concentration section;

the gas phase of the stripping and purifying tower passes through a fourth heat integration composite tower tube shell composite section tower section T4, exits a third composite tower shell section stripping and purifying section tower section external gas connecting pipeline G1 to a third heat integration composite tower tube shell composite section tower section T3 shell section, passes through a third heat integration composite tower tube shell composite section tower section T3, exits a second composite tower shell section stripping and purifying section tower section external gas connecting pipeline G2 to a second heat integration composite tower tube shell composite section tower section T2 shell section, passes through a second heat integration composite tower tube shell composite section T2, exits a first composite tower shell section stripping and purifying section tower section external gas connecting pipeline G3 to a first heat integration composite tower tube shell composite section tower section T1 shell section, and the composite tower stripping gas passes through a SA composite tower stripping section gas phase S3 pipeline and passes through a compressor D101 to a heat integration composite tower stripping gas washing section.

The SA rectification concentration section process comprises the following steps: liquid phase of a rectifying and concentrating section of the composite tower is uniformly distributed through a liquid phase distribution pipe F of a top gas-liquid distributor and then is distributed to a tower section T1 tube side packing section of a first heat integration composite tower tube shell composite section, liquid phase of a higher rectifying and concentrating section is uniformly distributed through the liquid phase distribution pipe F of the top gas-liquid distributor and then is distributed to a tower section T2 tube side packing section of a second heat integration composite tower tube shell composite section, liquid phase of the higher rectifying and concentrating section is uniformly distributed through the liquid phase distribution pipe F of the top gas-liquid distributor and then is distributed to a tower section T3 tube side packing section of a third heat integration composite tower tube shell composite section, liquid phase of the higher rectifying and concentrating section is uniformly distributed through the liquid phase distribution pipe F of the top gas-liquid distributor and then is distributed to a tower section T4 tube side packing section of a fourth heat integration composite tower tube shell composite section, liquid phase of the rectifying and concentrating section T4 of the fourth heat integration composite tower tube shell tower enters a rectifying and concentrating section of a heat integration composite tower C101, and liquid in two paths, one path of the tower bottom feed liquid S6 of the sulfuric acid rectification section of the composite tower is extracted, the other path of the tower bottom feed liquid is heated by a composite tower tube-pass tower bottom reboiler E101 and rises to a fourth heat integration composite tower tube-shell composite section tower section T4, is distributed by a top gas-liquid distributor gas-phase distribution pipe D and then uniformly rises to a third heat integration composite tower tube-shell composite section tower section T3 tube-pass filling section, is distributed by the top gas-liquid distributor gas-phase distribution pipe D and then uniformly rises to a second heat integration composite tower tube-shell composite section tower section T2 tube-pass filling section, is distributed by the top gas-liquid distributor gas-phase distribution pipe D and then uniformly rises to a first heat integration composite tower tube-shell composite section tower section T1 tube-pass filling section, the gas phase at the top end of the rectification concentration section passes through a composite tower sulfuric acid rectification concentration section top condenser E103 to an acid washing water buffer tank V102, and is used as washing water at the top of the composite tower washing section through an acid washing water circulating pump P102.

The heat integration composite tower washing section process comprises the following steps: the gas phase S3 from the top of the SA composite tower at the stripping and purifying section and the mixed gas S10 from the top of the HIX stripping and purifying section are compressed by a compressor D101, enter a stripping gas washing section of a C101 heat integration composite tower, and are washed by the sulfuric acid rectification and concentration section and the tower top produced water S9 of the SA unit composite tower to obtain a product discharge O₂The acid water S16 is extracted from the bottom of the washing section of the composite tower through an S11 pipeline.

The thermal decomposition and mixed gas conditioning of sulfuric acid and the process are as follows: concentrated sulfuric acid from the bottom of the concentration section of the C101 composite tower enters a sulfuric acid thermal decomposition reactor R101 through a sulfuric acid thermal decomposition reactor R101 feeding pump P101, is heated by an R101 feeding preheater E104 and then enters the sulfuric acid thermal decomposition reactor R101, decomposed mixed gas of the R101 enters a stripping gas storage tank V101, liquid phase of the stripping gas storage tank returns to the shell side stripping purification section of the heat integration composite tower C101 for feeding, and mixed gas at the bottom of the stripping purification section of the V101 stripping gas and SA composite tower supplements O₂The mixed gas is taken as SA composite tower stripping and purifying section tower bottom mixed gas S51 to enter a composite tower C101 shell side stripping and purifying section, and the V101 stripping gas and HIX stripping and purifying tower bottom mixed gas supplement O₂The blended gas is fed to HIX as HIX stripping purification column bottoms blending gas S52.

The process device for preparing oxygen by thermal decomposition of the sulfuric acid phase in the iodine-sulfur cycle utilizes the novel shell-and-tube composite structure of the heat integration composite tower C101, strengthens the mass transfer and heat transfer processes, couples the SA steam stripping purification section, the SA rectification concentration section and the steam stripping gas washing section of the whole process together, integrates the heat of the SA rectification concentration section into the SA steam stripping purification section, and realizes the energy conservation of the process and the system.

The invention mixes the gas phase S4 of the stripping tank and the extracted O₂The mixed gas is used as a vaporized and purified gas, and the mixed gas O of S51 at the bottom of the stripping and purifying section of the SA compound tower₂Molar flow of and SO₂In a molar flow ratio of more than 2: 3 and O₂The ratio of the molar flow of the SO (sulfur) to the molar flow of the HI impurities contained in the SA system is more than 1: 4, thereby avoiding using a gas source outside the system as stripping gas and improving the SO content in the SA₂Recovery rate of (3), purification of S, H of SA inclusions₂S and a small amount of HI;

the HIX stripping purification tower bottom S52 mixed gas O₂Molar flow of and SO₂The molar flow ratio is more than 1: 2 and less than 2: 1, thereby avoiding using a gas source outside the system as stripping gas, and improving SO in HIX₂The recovery rate of (2) is high, and S, H of HIX series inclusion is purified₂S and a small amount of H₂SO₄。

The invention returns the acidic water S16 extracted from the washing section of the composite tower at the bottom of the washing section of the composite tower C101 to the mixing tank in front of the Bunsen reactor, thereby improving the quality utilization rate of the system.

The invention is illustrated in detail below by means of several specific examples.

Example 1

By adopting the process, SA enters a C101 heat integration composite tower, the outer diameter of the novel composite tower is 250mm, the height of a composite tower section is 650mm, and the composite tower is made of corrosion-resistant and high-temperature-resistant stainless steel. The C101 heat integration composite tower stripping purification section and the rectification concentration section are respectively 8 trays, and the washing section comprises 10 trays. The pressure in the stripping and purification section was 1bar and the temperature in the stripper was 120 ℃. The pressure of the rectifying and concentrating section is 1bar, the feeding position is the 4 th plate, the feeding temperature is 125 ℃, the temperature of the top of the tower is 55 ℃, and the temperature of the bottom of the tower is 330 ℃. The pressure in the water washing section was 7bar and the temperature was 110 ℃. The C102 column contains 8 trays, the pressure is 1bar and the temperature of the C102 column is 120 ℃.

The reference number of the sulfuric acid phase thermal decomposition oxygen production unit stream in the iodine-sulfur cycle is consistent with that of the attached figure 1, and the material properties are shown as S1 in the table 1 of the example 1: s1 is the feed of the composite column stripping purification section SA with a total flow rate of 7.357kmol/h, and the tempered C101 stripping section stripping gas S51 contains 0.866kmol/h of SO₂And 0.730kmol/h of O₂C101 stripping section stripping gas purified stripping gas S3, containing 0.832kmol/h SO₂And 0.678kmol/h of O₂. A tempered C102 stripping section stripper gas S52 comprising 0.866kmol/h of SO2 and 0.490kmol/h of O₂C102 stripper purified stripping gas S10, containing 0.703kmol/h SO₂And 0.455kmol/h of O₂. After washing in the C10 water washing section, the composition of the acidic water at the bottom of the scrubber tower is shown as S16 in Table 1, and SO₂1.505kmol/h was recovered. The gas phase after the sulfuric acid decomposition of the reaction gas, which contained 0.866kmol/h of SO, was as S4 in Table 1₂And 0.490kmol/h of O₂。

C101 stripper blend O₂And SO₂In a ratio of 0.830, O₂And the ratio of HI in feed stream S1 was 6.892, the system was adjusted and the gas purified for small amounts of HI and part of the by-products in the SA acid phase:

a small amount of sulfuric acid undergoes the reverse reaction of the Bunsen reaction: 4HI + O₂＝2I₂+2H₂O；

The byproduct S reacts with the mixed gas: s + O₂＝SO₂Analysis S2 shows that the conversion rate of HI in the purification process of the stripping tower is 100%, and the aim of purifying the sulfuric acid phase SA is effectively achieved.

C102 stripper blend O₂And SO₂0.553, the system gas mixture is used for mixing a small amount of sulfuric acid in HIX acid phase with part of byproductsAnd (3) performing purification:

part of the sulfuric acid undergoes the reverse reaction of the Bunsen reaction: h₂SO₄+2HI＝SO₂+I₂+2H₂O；

Small amount of sulfuric acid and by-product H₂S is reacted: h₂SO₄+H₂S+O₂＝2SO₂+2H₂O；

The byproduct S reacts with the mixed gas: s + O₂＝SO₂Analysis of S10, S12 and S13 revealed that the by-product H was produced₂S conversion 95%, H₂SO₄The conversion rate in the purification process of the stripping tower is 100 percent, and the aim of HIX purification is effectively achieved. Under the stable condition, the latent heat of the reaction section is recovered by the steam stripping section, the energy is saved by 25.32KW, and compared with the equivalent 3-tower conventional process flow, the heat integration composite tower saves the space and the cost, and the annual total investment is saved by more than 25%.

Table 1 shows the material property parameters and compositions of example 1

Example 2

By adopting the flow of the invention, the structure and the process parameters are the same as those of the embodiment 1.

The reference number of the sulfuric acid phase thermal decomposition oxygen production unit stream in the iodine-sulfur cycle is consistent with that of the attached figure 1, and the material properties are shown as S1 in the table 2 of example 2: s1 is the feed of the composite column stripping purification section SA with a total flow rate of 9.507kmol/h, and the tempered C101 stripping section stripping gas S51 contains 0.866kmol/h of SO₂And 0.820kmol/h of O₂C101 stripping section stripping gas purified stripping gas S3, containing 0.832kmol/h SO₂And 0.630kmol/h of O₂. A tempered C102 stripper stripping gas S52 containing 0.866kmol/h SO₂And 0.490kmol/h of O₂C102 stripper purified stripping gas S10, containing 0.899kmol/h SO₂And 0.320kmol/h of O₂. After washing in the C10 water washing section, the composition of the acidic water at the bottom of the scrubber tower is shown as S16 in Table 1, and SO₂Recycling 1.702kmol/h. The gas phase after decomposition of the reaction gas with sulfuric acid was as shown in S4 in Table 1, and the decomposed gas contained 0.866kmol/h of SO2 and 0.490kmol/h of O₂。

C101 stripper blend O₂And SO₂In a ratio of 0.925, O₂And the ratio of HI in the feed stream S1 is 6.833, the system is adjusted and gasified to purify a small amount of HI and partial by-products in the SA acid phase, and analysis on S2 shows that the conversion rate of HI in the purification process of the stripping tower is 100 percent, so that the aim of purifying the SA in the sulfuric acid phase is effectively fulfilled. C102 stripper blend O₂And SO₂The ratio of the sulfuric acid to the by-product H is 0.565, the system gas mixture purifies a small amount of sulfuric acid and a part of the by-product in HIX acid phase, and the analysis on S10, S12 and S13 shows that the by-product H is₂S conversion 99%, H₂SO₄The conversion rate in the purification process of the stripping tower is 100 percent, and the aim of HIX purification is effectively achieved. Under the stable condition, the latent heat of the reaction section is recovered by the steam stripping section, the energy is saved by 26.85KW, and compared with the equivalent 3-tower conventional process flow, the heat integration composite tower saves the space and the cost, and the annual total investment is saved by more than 25%.

Table 2 shows the material property parameters and compositions of example 2

Example 3

By adopting the process, SA enters a C101 heat integration composite tower, the outer diameter of the novel composite tower is 300mm, the height of a composite tower section is 680mm, and the composite tower is made of corrosion-resistant and high-temperature-resistant stainless steel. The stripping purification section and the rectification concentration section of the C101 heat integration composite tower are respectively 8 trays, and the washing section comprises 8 trays. The pressure in the stripping and purification section was 1bar and the temperature in the stripper was 120 ℃. The pressure of the rectifying and concentrating section is 1bar, the feeding position is the 4 th plate, the feeding temperature is 125 ℃, the temperature of the top of the tower is 55 ℃, and the temperature of the bottom of the tower is 330 ℃. The pressure in the water washing section was 7bar and the temperature was 110 ℃. The C102 column contains 10 trays, the pressure is 1bar and the C102 column temperature is 120 ℃.

The material flow label of the sulfuric acid phase thermal decomposition oxygen production unit in the iodine-sulfur cycle is consistent with that of figure 1, and the material propertiesAs shown in example 3 at S1 in table 3: s1 is a combined column stripping purification section SA feed with a total flow rate of 5.907kmol/h, and a tempered C101 stripping section stripping gas S51 containing 0.805kmol/h of SO₂And 0.705kmol/h of O₂Stripping gas S3, containing 0.796kmol/h SO, after C101 stripping section stripping gas purification₂And 0.686kmol/h of O₂. A tempered C102 stripping section stripper gas S52, comprising 0.805kmol/h SO2 and 0.502kmol/h O₂C102 stripper purified stripping gas S10 containing 0.765kmol/h SO₂And 0.497kmol/h of O₂. After washing in the C10 water washing section, the composition of the acidic water at the bottom of the scrubber tower is shown as S16 in Table 1, and SO₂1.766kmol/h was recovered. The gas phase after decomposition of the reaction gas with sulfuric acid was as shown in Table 1 as the component S4, and the decomposed gas contained 0.805kmol/h of SO2 and 0.500kmol/h of O₂。

C101 stripper blend O₂And SO₂In a ratio of 0.876, O₂And the ratio of HI in feed stream S1 was 12.593, the system make-up and gas purified small amounts of HI in the SA acid phase with part of the by-products, analysis S2 showed that the conversion of HI during the stripper purification was 100%, the by-products S and H were₂The conversion rate of S is 100 percent, and the aim of purifying the sulfuric acid phase SA is effectively fulfilled. C102 stripper blend O₂And SO₂The ratio of (A) to (B) is 0.632, the system gas mixture purifies a small amount of sulfuric acid and partial by-products in HIX acid phase, and analysis on S10, S12 and S13 shows that H is₂SO₄The conversion rate in the purification process of the stripping tower is 100 percent, and the aim of HIX purification is effectively achieved. Under the stable condition, the latent heat of the reaction section is recovered by the steam stripping section, the energy is saved by 28.67KW, and compared with the equivalent 3-tower conventional process flow, the heat integration composite tower saves the space and the cost, and the annual total investment is saved by more than 30 percent.

Table 3 shows the material property parameters and compositions of example 3

Claims

1. A device for preparing oxygen by thermal decomposition of sulfuric acid in iodine-sulfur circulation is characterized by comprising a heat integration composite tower, an HIX stripping purification tower, a sulfuric acid thermal decomposition reactor, a feed pump, an acidic washing water circulating pump, a stripping gas storage tank, an acidic washing water buffer tank, a composite tower tube-pass tower bottom reboiler, a composite tower sulfuric acid rectification section feed preheater, a composite tower sulfuric acid rectification section top condenser, a sulfuric acid decomposition reactor feed preheater and a compressor;

the tower section of the heat integration composite section adopts a shell-and-tube structure, the shell pass of the heat integration composite section is communicated with the steam stripping purification section, the tube pass is communicated with the rectification concentration section, the tower section of each heat integration composite section is a single-stage theoretical stage, and the shell pass and the tube pass of the tower section of the heat integration composite section are respectively filled with fillers; n tower sections of the heat integration composite section are coaxially and hermetically connected, wherein N is more than or equal to 1; the heat integration composite section tower section comprises a rectification concentration section outer tower tray, a stripping purification section inner tower tray, a gas-liquid distributor, inner and outer tower tray sieve holes, a rectification concentration section tube nest, a composite tower section tower wall, a composite tower section flange, a stripping purification section liquid phase inlet and outlet, a stripping purification section vapor phase inlet and outlet and a tube shell pass bottom packing fixing plate;

the shell of the tower section in the heat integration composite tower is formed by the tower wall of the composite tower section, the lower flange of the composite tower section and the upper flange of the composite tower section; the upper part of the composite tower section wall is provided with a shell pass stripping purification section tower section liquid feed inlet and a stripping purification section tower section vapor outlet, the lower part of the composite tower section wall is provided with a stripping purification section tower section vapor inlet and a shell pass stripping purification section tower section liquid outlet, the shell pass stripping purification section tower section liquid outlet is welded between a shell pass bottom filler fixing plate and a tube pass bottom filler fixing plate, the stripping purification section tower section vapor outlet is welded between an outer tower tray and an inner tower tray liquid inlet, the stripping purification section tower section vapor inlet is welded at the upper part of the shell pass bottom filler fixing plate, and the shell pass stripping purification section tower section liquid feed inlet is welded between the outer tower tray and the inner tower tray;

a stripping purification section inner tower tray, a rectification concentration section outer tower tray, a shell side bottom filler fixing plate and a tube side bottom filler fixing plate are fixed in the shell; the inner tray of the stripping purification section is fixed on the shell pass, and the outer tray of the rectification concentration section is fixed on the tube pass; holes are formed in the shell pass bottom filler fixing plate and the tube pass bottom filler fixing plate; sieve holes are arranged on the inner tower tray of the stripping purification section and the outer tower tray of the rectification concentration section, a gas-liquid distributor is welded in the sieve holes, and the aperture of each sieve hole is the same as the outer diameter of a liquid phase outlet of the gas-liquid distributor; the gas-liquid distributor is mainly formed by nesting a liquid phase pipe and a gas phase pipe, wherein the top of the gas phase pipe is used as a gas phase outlet, and the bottom of the gas phase pipe is used as a gas phase inlet; the top of the liquid phase pipe is used as a liquid phase inlet, and the bottom of the liquid phase pipe is used as a liquid phase outlet;

the top of the stripping gas water washing section of the heat integration composite tower is provided with O₂The side part of the extraction port is provided with acidic water H₂A washing acidic water extraction port is formed at the bottom of the feeding port O; the top of the shell side stripping purification section of the heat integration composite tower is provided with a stripping gas outlet of the stripping purification section of the heat integration composite tower, and the outlet is communicated with a gas inlet of the water washing section of the composite tower through a compressor in sequence by a pipeline; the upper part of the shell side steam stripping purification section of the heat integration composite tower is provided with a liquid phase inlet, and the lower part of the shell side steam stripping purification section of the heat integration composite tower is provided with a gas phase gas inlet and a liquid phase extraction outlet; a liquid phase outlet of the shell-side stripping purification section is connected with a liquid phase inlet of a tube-side rectification concentration section of the heat integration composite tower after passing through a rectification concentration section preheater; the bottom of the tower kettle of the tube pass rectification concentration section of the heat integration composite tower is provided with a liquid phase extraction port and a gas phase inlet, a pipeline from the liquid phase extraction port is divided into two paths, and one path is reboiled through the bottom of the composite tower tube pass towerThe liquid enters from a gas phase inlet at the bottom of a rectifying and concentrating section tower kettle; the other path enters the sulfuric acid decomposition reactor through a feed pump and a preheater of the sulfuric acid decomposition reactor; the upper part of the HIX stripping and purifying tower is provided with a HIX material-based inlet, the bottom of the HIX stripping and purifying tower is provided with a HIX purified liquid outlet, the bottom of the HIX stripping and purifying tower is provided with a stripping and purifying gas inlet, and the top of the HIX stripping and purifying tower is provided with a stripping and purifying gas outlet;

the stripping gas storage tank is provided with a gas inlet, a gas outlet and a discharge hole, the discharge hole is connected with a liquid phase feed inlet at the top of the stripping and purifying section of the composite tower, and the gas outlet is respectively connected with a gas phase inlet at the bottom of the stripping and purifying section of the composite tower and a gas phase inlet at the bottom of the stripping and purifying section of HIX;

the sulfuric acid decomposition reactor is provided with a feed inlet and an air outlet, and the air outlet is connected with a gas phase air inlet of a stripping gas storage tank.

2. The device of claim 1, wherein the total number of trays in the stripping and purifying section is N1, N1 is more than or equal to 1; the total number of the outer trays of the rectifying and concentrating section is N2, and N2 is more than or equal to 1; external pipelines of the rectifying and concentrating section of the shell-and-tube composite tower are connected step by step to form a symmetrical structure with the same theoretical stages of the rectifying and concentrating section and the stripping and purifying section, namely N1 is N2; or the external pipeline of the rectifying and concentrating section of the composite tower is bridged to form an asymmetric structure with unequal theoretical stages of the rectifying and concentrating section and the stripping and purifying section, namely N1 is not equal to N2.

3. The device according to claim 1 or 2, wherein the outer diameter of the heat-integrated shell-and-tube composite tower is 100-8000 mm.

4. A process for preparing oxygen by thermal decomposition of sulfuric acid in an iodine-sulfur cycle by using the apparatus of any one of claims 1 to 3, wherein the process comprises a process of SA stripping purification section, a process of SA rectification concentration section, a process of water washing section, and a process of thermal decomposition of sulfuric acid and mixed gas regulation;

and SA stripping and purifying section process: SA feed from a post-separator of the Bunsen reactor enters a shell side SA stripping purification section of the heat integration composite tower, and gas phase of a stripping gas storage tank is blended to contain SO₂And O₂SA composite tower steamThe bottom regulating gas of the stripping and purifying section is used as stripping gas of the SA stripping and purifying section, and heat is provided by the tube pass SA rectifying and concentrating section; liquid phase SA feed of the SA steam stripping purification section is distributed through a gas-liquid distributor on a shell side tower tray of the SA steam stripping purification section, liquid is uniformly distributed to packing of the tower section shell side steam stripping purification section, the packing is sequentially contacted downwards through a plurality of stages of external connecting pipelines for communicating each tower section to transfer mass, and finally the packing is collected through a bottom tank of the shell side tower of the composite tower, and the collected liquid phase enters a tube side rectification concentration section of the heat integration composite tower after being preheated by a feed preheater of a sulfuric acid rectification concentration section of the composite tower; the gas phase of the SA steam stripping purification section sequentially upwards contacts the liquid phase step by step through the shell section of the composite tower, and the gas phase at the top of the SA steam stripping purification section is compressed by a compressor and then flows to the washing section of the composite tower;

the SA rectification concentration section process comprises the following steps: liquid phase of the SA rectification concentration section is uniformly distributed through a liquid phase distribution pipe of a top gas-liquid distributor, then is transferred to a tube side filling section of a tube side shell composite section tower section of the heat integration composite tower, and is sequentially transferred downwards to a rectification concentration section tower kettle of the heat integration composite tower, tower kettle liquid is divided into two paths, one path of the liquid phase is extracted to form a tower bottom liquid of a sulfuric acid rectification concentration section of the composite tower, the other path of the liquid phase is heated by a reboiler at the bottom of the composite tower tube side tower and is lifted to a tube side sulfuric acid rectification concentration section tower section of the last stage of the heat integration composite tower, and is uniformly lifted to the tube side filling section of the tube side shell composite section tower section of the upper stage of the heat integration composite tower after being distributed through a gas phase distribution pipe of the top gas-liquid distributor, and is sequentially transferred upwards to the tube side shell composite section tower section of the first stage of the heat integration composite tower, gas phase at the top end of the rectification concentration section passes through a condenser at the top of the composite tower sulfuric acid rectification section to an acid washing water buffer tank, and then enters a washing section of the heat integration composite tower through an acid washing water circulating pump to be used as washing water at the top of the washing section, removing O from HIX stripping purified top gas mixture₂External SO₂Washing with other components, and extracting acidic water from the washing section of the compound tower to a mixing tank before Bunsen reaction;

and (3) a water washing section process: the gas phase at the top of the SA composite tower stripping and purifying section from the shell pass of the thermal integration composite tower and the mixed gas at the top of the HIX stripping and purifying section are compressed by a compressor and then enter a water washing section of the thermal integration composite tower, and a product O is obtained from the top of the sulfuric acid rectification and concentration section of the composite tower after water washing₂The acid water is extracted through a pipeline and is treated by the washing section of the compound towerExtracting from the bottom of a water washing section of the heat integration composite tower;

the thermal decomposition and mixed gas conditioning of sulfuric acid and the process are as follows: the feed liquid at the bottom of the sulfuric acid rectification concentration section from the compound tower passes through a feed pump and then is heated by a feed preheater and then enters a sulfuric acid thermal decomposition reactor, the decomposed mixed gas of the sulfuric acid thermal decomposition reactor enters a stripping gas storage tank, the feed liquid at the bottom of a stripping tank of the stripping gas storage tank returns to the heat integration compound tower to be used as the feed of an SA stripping purification section, and the stripping gas and the extracted O in the stripping gas storage tank₂The mixed stripping and purifying gas respectively enters a stripping and purifying section of the heat integration composite tower and an HIX stripping and purifying tower.

5. The process of claim 4 wherein the SA stripping purification section will contain SO₂The sulfuric acid decomposition mixture and pure O extracted from the water washing section₂The mixture is taken as heat integration composite tower bottom purified gas of an SA stripping purification section after being blended, and O in the purified gas₂Molar flow of and SO₂Has a molar flow ratio of more than 2: 3 and O₂The ratio of the molar flow of (b) to the molar flow of HI impurities contained in the SA system is greater than 1: 4.

6. The process of claim 4 or 5, wherein the HIX stripping purification column contains SO₂The sulfuric acid decomposition mixture and pure O extracted from the water washing section₂The mixed gas is used as purified gas at the bottom of a HIX stripping purification tower, and O in the purified gas₂Molar flow of and SO₂The molar flow ratio of (a) is greater than 1: 2 and less than 2: 1.

7. The process according to claim 4 or 5, wherein the column pressure of the stripping and purification section of the combined column is controlled at 1bar, and the temperature is 110-130 ℃; the tower pressure of the rectifying and concentrating section of the composite tower is controlled to be 1bar, the temperature of the top of the tower is 50-60 ℃, and the temperature of the bottom of the tower is 310-350 ℃; the tower pressure of the water washing section of the composite tower is controlled to be 5-7 bar, and the temperature is 110-130 ℃; HIX stripping and purifying tower, the tower pressure is controlled at 1bar, and the temperature is 110-130 deg.C.

8. The process according to claim 6, wherein the column pressure of the stripping and purification section of the combined column is controlled at 1bar, and the temperature is 110-130 ℃; the tower pressure of the rectifying and concentrating section of the composite tower is controlled to be 1bar, the temperature of the top of the tower is 50-60 ℃, and the temperature of the bottom of the tower is 310-350 ℃; the tower pressure of the water washing section of the composite tower is controlled to be 5-7 bar, and the temperature is 110-130 ℃; HIX stripping and purifying tower, the tower pressure is controlled at 1bar, and the temperature is 110-130 deg.C.