Method and device for hydrogen production by thermochemical sulfur-iodine cycle and mineralization of carbon dioxide

Abstract

The application belongs to the field of CO2 emission reduction and thermochemical hydrogen production, and particularly relates to a method and device for thermochemical sulfur-iodine cycle hydrogen production and carbon dioxide mineralization, which comprises the following steps: reacting a mixed solution of Bunsen reaction with magnesium silicate minerals to generate MgI2, MgSO4 and SiO2; concentrating and crystallizing the separated solution to obtain MgI2 and MgSO4 crystals; reacting the crystals with CO2 and water vapor to generate HI, MgCO3 and MgSO4 crystals, discharging the HI gas, dissolving the MgCO3 and MgSO4 crystals in water and filtering; decomposing the MgSO4 at high temperature into MgO, SO2 and O2, and returning the gas to participate in the Bunsen reaction; and separating hydrogen gas product from I2 and hydrogen gas generated in the HI decomposition and unreacted HI gas through spray washing, and returning the washing liquid to participate in the Bunsen reaction. The application mineralizes and fixes CO2 under mild reaction conditions, simultaneously produces H2, and is easy to realize large-scale industrial application.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of CO2 emission reduction and thermochemical hydrogen production, and particularly relates to a method and device for thermochemical sulfur-iodine cycle hydrogen production and carbon dioxide mineralization. BACKGROUND

[0002] At present, CO2 capture and storage (CCS) technology is the main end-of-pipe emission reduction strategy and has been widely studied. However, due to the high cost and energy consumption of existing CCS technology, its commercial application still faces economic problems. Moreover, CO2 geological storage may also have a series of risks, such as gas leakage, groundwater pollution, and even geological disasters. Carbon dioxide mineralization utilization is a new carbon dioxide emission reduction technology, which can convert carbon dioxide into stable minerals, thereby realizing long-term storage and utilization of carbon dioxide. This technology not only can reduce carbon dioxide emissions, but also can produce products with certain added value, and is expected to develop into a CO2 control and utilization technology for large-scale application in the future. The raw material in CO2 mineralization utilization technology is the source of alkaline earth metal cations required for mineralization reaction, and the abundance of raw material fundamentally determines the upper limit of mineralization capacity. Alkaline earth metal minerals in nature, mainly magnesium silicate ores such as serpentine and olivine, have a mineralization capacity equivalent to 36,000 GtCO2. CO2 mineralization must use alkaline earth metal minerals, i.e. calcium magnesium silicate, as raw material. On the other hand, the main product of CO2 mineralization technology is calcium magnesium carbonate, which has low economic value and added value, which is an important factor restricting its commercial application. If a CO2 mineralization technology has high-value and economic by-products, or can be organically combined with other more economic energy technologies, it will be more dynamic.

[0003] Hydrogen energy is a secondary energy source, also known as zero-pollution efficient energy, which can be produced by various methods. Moreover, in the combustion process, it can be directly converted into electricity and water, without emitting any pollutants. Water can be used to produce hydrogen through thermal dissociation, but the reaction requires a high temperature of 2500°C or above. The sulfur-iodine cycle hydrogen production method divides the water dissociation reaction into several steps, which can not only reduce the reaction temperature, but also avoid the hydrogen-oxygen separation problem, and the sulfur dioxide and iodine used in the cycle can be recycled. The sulfur-iodine (SI) cycle was first proposed by General Atomics in the 1970s. Due to its many advantages, including easy continuous operation of the whole flow phase process, high energy utilization efficiency, complete closed cycle, and compatibility with nuclear or solar energy, the sulfur-iodine cycle has the potential for large-scale and low-cost hydrogen production. The Bunsen reaction is an exothermic SO2 gas absorption reaction that occurs spontaneously in the liquid phase at a temperature of 20-100°C, generating mutually soluble HI and H2SO4. Excess iodine and water must be added to separate the two acids.

[0004] The prior art has reported cases of combining two technologies, for example, Chinese invention patent publication number: CN108821315B, name: method and device for mineralizing CO2 and simultaneously decomposing H2O to produce H2 by thermochemical cycle. The invention patent proposes to combine CO2 mineralization technology with thermochemical sulfur-iodine open cycle water decomposition hydrogen production, to mineralize and fix CO2 under relatively mild reaction conditions, while co-producing H2 with high added value; the organic combination of hydrogen production cycle and mineralization technology skillfully avoids the HI-I2 rectification separation process in traditional hydrogen production cycle, and the cycle has higher theoretical thermal efficiency. The theoretical thermal efficiency of the invention seems higher, but it needs to invest excess iodine, which not only increases the initial investment cost, but also increases the risk of iodine deposition blocking the pipeline, and uses electrodialysis method to concentrate hydroiodic acid, which further increases the operation and maintenance cost. For another example, Chinese invention patent publication number: CN108715438B, name: method and device for mineralizing CO2 and simultaneously decomposing H2O to produce H2 and co-produce H2SO4 by thermochemical cycle. The invention patent similarly proposes to combine CO2 mineralization technology with thermochemical sulfur-iodine open cycle water decomposition hydrogen production technology, but it has similar shortcomings as CN108821315B. SUMMARY

[0005] In view of the problems existing in the prior art, the present application provides a method and device for thermochemical sulfur-iodine cycle hydrogen production and carbon dioxide mineralization, which eliminates the separation step of hydroiodic acid and sulfuric acid, reduces the input amount of iodine and water, reduces the cost of acid solution concentration and the risk of iodine deposition blocking the pipeline, ensures the continuity of system operation, and uses the energy of the high-temperature gas produced by decomposition for distillation and concentration, realizing energy recycling.

[0006] In one aspect, the present application provides a method for thermochemical sulfur-iodine cycle hydrogen production and carbon dioxide mineralization, which comprises (S1) I2, SO2, and H2O undergo Bunsen reaction to generate a mixed solution, and the mixed solution reacts with magnesium silicate minerals to generate MgI2, MgSO4, and SiO2, wherein SiO2 is filtered out as a byproduct;

[0007] (S2) The MgI2 and MgSO4 solution is concentrated and crystallized to obtain MgI2·nH2O crystals and MgSO4·nH2O crystals;

[0008] (S3) The MgI2·nH2O crystals and MgSO4·nH2O crystals are reacted with the introduced CO2 and water vapor to generate HI gas, MgCO3, and MgSO4·nH2O crystals, the HI is discharged in gas form, and the MgCO3 and MgSO4·nH2O crystals are dissolved in water and then filtered and separated, and the collected MgCO3 is output as a byproduct;

[0009] (S4) MgSO4 high temperature decomposition to generate MgO, SO2 and O2, high temperature gas as (S2) solution concentration heat source, heat exchange cooling and return to (S1) to participate in Bunsen reaction;

[0010] (S5) HI decomposition and produce I2 and hydrogen and unreacted HI gas by spraying washing, the liquid from the (S1) Bunsen reaction generated by spraying mixed liquid, washing after hydrogen discharge as product output, spraying washing liquid returns to (S1) cycle and participate in Bunsen reaction.

[0011] In particular, the (S1) Bunsen reaction conditions are 20-120℃, 1-2atm, the liquid phase reaction raw material in Bunsen reaction comes from (S5) spraying washing liquid and external water supplement.

[0012] In particular, the (S1) Bunsen reaction generated mixed liquid and magnesium silicate mineral reaction temperature is controlled at 20-90℃.

[0013] In particular, the (S3) reaction temperature is controlled at 180-250℃.

[0014] In particular, the (S4) MgSO4 decomposition at 1000-1200℃, the reaction of MgO back to (S3), MgO and CO2 reaction to generate MgCO3, the reaction of high temperature gas back to (S2) for concentration, crystallization provides energy.

[0015] In particular, the (S5) HI gas in 450-500℃, the presence of catalyst, decomposition into I2 and H2, I2 and unreacted HI by spraying washing, hydrogen as product output.

[0016] In particular, the magnesium silicate mineral is natural ore, the natural ore is serpentine and / or peridot.

[0017] In another aspect, the present application also provides a device for thermochemical sulfur-iodine cycle hydrogen production while mineralizing carbon dioxide, comprising Bunsen reactor 1, salt generation reactor 2, distillation device 4, hydrolysis carbonation reactor 5 connected in turn, hydrolysis carbonation reactor 5 is connected with HI decomposer 8 and MgSO4 dissolver 6 respectively, HI decomposer 8 is connected with condenser 3 and Bunsen reactor 1; MgSO4 dissolver 6 is connected with MgSO4 decomposer 7; the device operates according to the above method.

[0018] In particular, the Bunsen reactor 1 comprises at least two liquid inlets, two liquid outlets, one gas inlet and one gas outlet. One liquid inlet is connected to the condenser 3 for the introduction of the iodine-containing mixture after the spray washing. One liquid inlet is used for the external supply of water. One liquid outlet is connected to the condenser 3 for the discharge of the mixture for spraying. One liquid outlet is connected to the salt generation reactor 2 for the discharge of the mixture. One gas inlet is used for the reception of SO2 and oxygen after the heat exchange in the distillation device 4. One gas outlet is used for the discharge of the product oxygen.

[0019] The salt generation reactor 2 comprises at least one liquid inlet, one liquid outlet, one solid inlet and one solid outlet. The liquid inlet is used for the reception of the mixture of HI and H2SO4 discharged from the Bunsen reactor 1. One liquid outlet is connected to the distillation device 4 for the discharge of the mixture of MgI2 and MgSO4. One solid inlet is used for the supply of magnesium silicate ore. One solid outlet is used for the discharge of the by-product SiO2.

[0020] The distillation device 4 comprises at least one liquid inlet, one solid outlet, one gas inlet and one gas outlet. The liquid inlet is used for the reception of the mixture of MgI2 and MgSO4. One solid outlet is used for the discharge of the crystals of MgI2 nH2O and MgSO4 nH2O. One gas inlet is used for the reception of the high-temperature SO2 and O2 produced by the MgSO4 decomposer 7. One gas outlet is used for the discharge of the SO2 and O2 after the heat exchange.

[0021] The hydrolytic carbonation reactor 5 comprises at least two solid inlets, one solid outlet, one gas inlet and one gas outlet. One solid inlet is used for the reception of the crystals of MgI2 nH2O and MgSO4 nH2O. One solid inlet is used for the reception of the MgO solid produced by the MgSO4 decomposer 7. One solid outlet is used for the discharge of the MgCO3 and the crystals of MgSO4 nH2O. One gas inlet is used for the reception of water vapor and CO2. One gas outlet is used for the discharge of the HI gas.

[0022] The HI decomposer 8 is connected to the hydrolytic carbonation reactor 5. The HI gas discharged from the hydrolytic carbonation reactor 5 enters the HI decomposer 8 for decomposition.

[0023] The condenser 3 comprises at least one liquid inlet, one liquid outlet, one gas inlet and one gas outlet. The liquid inlet is connected to the Bunsen reactor 1 for the reception of the mixture of HI and H2SO4. One liquid outlet is connected to the Bunsen reactor 1 for the discharge of the iodine-containing mixture after the washing. One gas inlet is connected to the HI decomposer 8 for the reception of HI, I2 and H2. One gas outlet is used for the discharge of the product hydrogen.

[0024] The MgSO4 dissolver 6 comprises at least one liquid phase inlet for external water supplement, one liquid phase outlet connected with the MgSO4 decomposer 7 for discharging MgSO4 solution, one solid phase inlet connected with the hydrolytic carbonation reactor 5 for collecting MgCO3 and MgSO4 nH2O crystals, and one solid phase outlet for discharging byproduct MgCO3.

[0025] The MgSO4 decomposer 7 is connected with the MgSO4 dissolver 6 for collecting MgSO4 and decomposing.

[0026] The above technical solution has the following advantages or beneficial effects: the application innovatively combines the CO2 mineralization technology with the thermochemical sulfur-iodine cycle water-splitting hydrogen production, mineralizes and fixes CO2 under relatively mild reaction conditions, and simultaneously produces H2 with high added value; by omitting the separation steps of hydroiodic acid and sulfuric acid, the iodine and water input is reduced, the cost of acid solution concentration and the risk of iodine deposition blocking the pipeline are reduced, the continuity of system operation is ensured, and the purification step of removing sulfuric acid from the hydroiodic acid phase is not required, which is beneficial to system simplification. High-temperature SO2 and oxygen provide part of the heat for the distillation system, realizing energy recycling and utilization, and the application is more suitable for large-scale industrial application. Of course, any technical solution of the application does not necessarily achieve all the above advantages at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, other drawings can also be obtained by the provided drawings without creative labor for those skilled in the art.

[0028] Figure 1 is the full process flow diagram of the method and device for thermochemical sulfur-iodine cycle hydrogen production and carbon dioxide mineralization of the application.

[0029] Among them, 1-Bunsen reactor, 2-salt generation reactor, 3-condenser, 4-distillation device, 5-hydrolytic carbonation reactor, 6-MgSO4 dissolver, 7-MgSO4 decomposer, 8-HI decomposer. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the application will be described clearly and completely below in combination with the drawings of the application. Obviously, the described embodiments are only part of the embodiments of the application, and are intended to explain the inventive concept. Based on the embodiments of the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0031] Unless otherwise explicitly specified and limited, the terms "connection," "connection," etc., used in the description should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments according to the specific circumstances.

[0032] The term "a specific embodiment" as used in the description means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0033] like Figure 1 As shown in the figure, a specific embodiment of the thermochemical sulfur-iodine cycle hydrogen production and simultaneous carbon dioxide mineralization apparatus proposed in this application mainly includes a Bunsen reactor 1, a salt generation reactor 2, a condenser 3, a distillation unit 4, a hydrolysis-carbonation reactor 5, a MgSO4 dissolver 6, a MgSO4 decomposer 7, and an HI decomposer 8. The Bunsen reactor 1, salt generation reactor 2, distillation unit 4, and hydrolysis-carbonation reactor 5 are connected sequentially. The hydrolysis-carbonation reactor 5 is then connected to the HI decomposer 8 and the MgSO4 dissolver 6, respectively. The HI decomposer 8 is then connected to the condenser 3 and the Bunsen reactor 1. The MgSO4 dissolver 6 is then connected to the MgSO4 decomposer 7.

[0034] This application also provides an apparatus for thermochemical sulfur-iodine cycle hydrogen production and simultaneous carbon dioxide mineralization, including a Bunsen reactor 1, which includes at least two liquid inlets, two liquid outlets, one gas inlet, and one gas outlet. One liquid inlet is connected to a condenser 3 for introducing an iodine-containing mixed solution after spray washing, one liquid inlet is for external water replenishment, one liquid outlet is connected to the condenser 3 for discharging the sprayed mixed solution, one liquid outlet is connected to a salt generation reactor 2 for discharging the mixed solution, one gas inlet is for receiving SO2 and oxygen after heat exchange in a distillation unit 4, and one gas outlet discharges product oxygen to the outside.

[0035] The salt generating reactor 2 comprises at least one liquid phase inlet, one liquid phase outlet, one solid phase inlet and one solid phase outlet, the liquid phase inlet is used to receive the mixed solution of HI and sulfuric acid discharged from the Bunsen reactor 1, the liquid phase outlet is connected with the distillation device 4 for discharging the mixed solution of MgI2 and MgSO4, the solid phase inlet is used to supplement the magnesium silicate ore, and the solid phase outlet is used to discharge the by-product SiO2.

[0036] The distillation device 4 comprises at least one liquid phase inlet, one solid phase outlet, one gas phase outlet and one gas phase inlet, the liquid phase inlet is used to receive the mixed solution of MgI2 and MgSO4, the solid phase outlet is used to discharge the MgI2·nH2O crystal and the MgSO4·nH2O crystal, the gas phase inlet is used to receive the high-temperature SO2 and O2 generated by the MgSO4 decomposer 7, and the gas phase outlet is used to discharge the heat-exchanged SO2 and O2.

[0037] The hydrolysis carbonation reactor 5 comprises at least two solid phase inlets, one solid phase outlet, one gas phase inlet and one gas phase outlet, one solid phase inlet is used to receive the MgI2·nH2O crystal and the MgSO4·nH2O crystal, one solid phase inlet is used to receive the MgO solid generated by the MgSO4 decomposer 7, the solid phase outlet is used to discharge the MgCO3 and the MgSO4·nH2O crystal, the gas phase inlet is used to receive the water vapor and CO2, and the gas phase outlet is used to discharge the HI gas.

[0038] The HI decomposer 8 is connected with the hydrolysis carbonation reactor 5, and the HI gas discharged from the hydrolysis carbonation reactor 5 enters the HI decomposer 8 for decomposition.

[0039] The condenser 3 comprises at least one liquid phase inlet, one liquid phase outlet, one gas phase inlet and one gas phase outlet, the liquid phase inlet is connected with the Bunsen reactor 1 for receiving the mixed solution of HI and H2SO4, the liquid phase outlet is connected with the Bunsen reactor 1 for discharging the mixed solution containing iodine after washing, the gas phase inlet is connected with the HI decomposer 8 for receiving the HI, I2 and H2, and the gas phase outlet is used to discharge the product hydrogen.

[0040] The MgSO4 dissolver 6 comprises at least one liquid phase inlet, one liquid phase outlet, one solid phase inlet and one solid phase outlet, the liquid phase inlet is used to supplement water from outside, the liquid phase outlet is connected with the MgSO4 decomposer 7 for discharging the MgSO4 solution, the solid phase inlet is connected with the hydrolysis carbonation reactor 5 for receiving the MgCO3 and the MgSO4·nH2O crystal, and the solid phase outlet is used to discharge the by-product MgCO3 to the outside.

[0041] The MgSO4 decomposer 7 is connected with the MgSO4 dissolver 6 for receiving the MgSO4 and performing decomposition.

[0042] One specific embodiment of the present application proposes a method of hydrogen production and carbon dioxide mineralization by thermo-chemical sulfur-iodine cycle, which comprises the following steps. In Bunsen reactor 1, an exothermic reaction occurs spontaneously at 20-120℃ and 1-2 atm, generating a mixture of HI and H2SO4, and the chemical reaction is as follows: I2 + SO2 + 2H2O = 2HI + H2SO4. The liquid-phase reaction raw materials in Bunsen reactor 1 come from condenser 3 and external water supplement, and the gas-phase reaction raw materials come from MgSO4 decomposition tower 7.

[0043] The mixture of HI and H2SO4 discharged from Bunsen reactor 1 enters salt generation reactor 2, and spontaneously reacts with magnesium silicate natural minerals at a reaction temperature of 20-90℃, generating MgSO4, MgI2 and SiO2, of which SiO2 is filtered out as a byproduct.

[0044] MgI2 and MgSO4 solution enters distillation device 4 for concentration and crystallization, obtaining MgI2·nH2O crystals and MgSO4·nH2O crystals. Preferably, the high-temperature SO2 and O2 generated by the high-temperature decomposition of MgSO4 in MgSO4 decomposer 7 can be used together with external heat source to provide energy for distillation and crystallization, and the remaining MgI2·nH2O and MgSO4·nH2O crystals in distillation device 4.

[0045] MgI2·nH2O crystals and MgSO4·nH2O crystals enter hydrolysis carbonation reactor 5, and CO2 and water vapor are introduced, and the reaction temperature is controlled at 180-250℃ (higher than the boiling point of HI -35.5℃, and lower than the boiling point of H2SO4 338℃), and MgI2 can react as follows: MgI2 + H2O + CO2 = MgCO3 + 2HI. At 180-250℃, HI continuously leaves in gas form, realizing gas-solid separation of the product, and the hydrolysis carbonation reaction of MgI2 can continuously proceed until the reactants are consumed. At 180-250℃, H2SO4 cannot leave the reactor in gas form, so MgSO4 cannot undergo hydrolysis carbonation reaction and still exists as MgSO4. At the same time, MgO from MgSO4 decomposer 7 reacts as follows: MgO + CO2 = MgCO3.

[0046] The generated HI gas is discharged into HI decomposer 8, and at 450-500℃, in the presence of a catalyst, the following reaction occurs: 2HI = I2 + H2. I2 and unreacted HI are removed by washing in condenser 3, and the spray liquid in condenser 3 comes from the mixture in Bunsen reactor 1, which is returned to Bunsen reactor 1 in the form of mixture after spray washing for the next cycle, and hydrogen is output as a product.

[0047] The generated MgC03 and MgS04-nH20 crystals enter the MgS04 dissolver 6, and the filtered MgC03 is output as a byproduct; the MgS04 enters the MgS04 decomposer 7, where the following reaction occurs at 1000-1200°C: 2MgS04 = 2MgO + 2SO2 + O2, the MgO is sent to the hydrolysis carbonation reactor 5 to generate MgC03, and the high-temperature SO2 and oxygen generated in the MgS04 decomposer 7 are sent to the distillation device 4 to provide part of the energy for concentration and crystallization and are finally returned to the Bunsen reactor 1, SO2 enters the next cycle, and O2 is output as a product.

[0048] Taking the magnesium silicate natural mineral serpentine Mg3Si205(OH)4 as an example, the overall reaction of the entire process is: Mg3Si205(OH)4 + 3CO2 + H2O = 3MgC03 + 3H2 + 2Si02 + 1.5O2.

[0049] The present application combines the CO2 mineralization technology with the thermochemical sulfur-iodine cycle to decompose water to produce hydrogen, and mineralizes and fixes CO2 under relatively mild reaction conditions while co-producing H2 with high added value; the separation steps of hydroiodic acid and sulfuric acid are omitted, not only reducing the input amount of iodine and water, but also reducing the cost of acid solution concentration and the risk of iodine deposition blocking the pipeline, ensuring the continuity of system operation, and the hydroiodic acid phase does not need to be purified by removing sulfuric acid, which is conducive to system simplification. High-temperature SO2 and oxygen provide part of the heat for the distillation system, achieving energy recycling. Each part of the system belongs to a chemical process, the reaction temperature is appropriate, and it is easy to realize large-scale industrial application. Example 1

[0050] 150 mol of H2O, 20 mol of I2 and 20 mol of SO2 are sent into the Bunsen reactor 1, and the following self-sustaining exothermic reaction occurs at 80°C and normal pressure: I2 + SO2 + 2H2O = 2HI + H2SO4. The generated HI (56.5%wt) and H2SO4 (21.6%wt) react with serpentine in the salt generation reactor 2 at a temperature of 60°C, and the chemical reaction is as follows: 6HI + Mg3Si205(OH)4 = 3MgI2 + 5H2O + 2SiO2, 3H2SO4 + Mg3Si205(OH)4 = 3MgSO4 + 5H2O + 2SiO2.

[0051] The mixture of MgI2, MgSO4, H2O and SiO2 generated in the reaction is filtered and washed to obtain the byproduct SiO2, and the filtrate is sent to the distillation device 4 for concentration and crystallization, and the MgI2-nH2O and MgSO4-nH2O crystals obtained are sent to the hydrolysis carbonation reactor 5, while CO2 and water vapor are introduced for hydrolysis carbonation reaction, and the reaction temperature is controlled at 200°C, and finally HI gas and product MgCO3 are obtained; the chemical reaction formula of the reaction is as follows: MgI2+H2O+CO2=MgCO3+2HI.

[0052] The generated HI gas is sent to the HI catalytic decomposition reactor, and reacts at 500°C, and the generated I2 and HI are washed and removed in the condensation tower, and hydrogen is output as a product, and the iodine-containing liquid returns to the Bunsen reactor 1 for the next cycle. The mixture of MgSO4-nH2O crystals and MgCO3 solids is filtered and washed in the MgSO4 dissolver 6 to obtain the byproduct MgCO3, and the MgSO4 enters the MgSO4 decomposer 7, and the following reaction occurs at 1100°C: 2MgSO4=2MgO+2SO2+O2. The generated SO2 and O2 (molar flow ratio 2:1) are sent to the distillation device 4 to provide part of the energy for the concentration and crystallization of the mixture, and the MgO solid is sent to the hydrolysis carbonation reactor 5, and the reaction occurs at 200°C: MgO+CO2=MgCO3. The generated MgCO3 is subjected to subsequent treatment and output as a byproduct. Example 2

[0053] 100 mol H2O, 10 mol I2 and 10 mol SO2 are sent to the Bunsen reactor 1, and the self-sustaining exothermic reaction occurs at 80°C and normal pressure as follows: I2+SO2+2H2O=2HI+H2SO4. The generated HI (51.0%wt) and H2SO4 (19.7%wt) react with olivine in the salt generation reactor 2, and the temperature is controlled at 60°C, and the chemical reaction is as follows: 4HI+Mg2SiO4=2MgI2+2H2O+SiO2, 2H2SO4+Mg2SiO4=2MgSO4+2H2O+SiO2.

[0054] The mixture of MgI2, MgSO4, H2O and SiO2 generated in the reaction is filtered and washed to obtain the byproduct SiO2, and the filtrate is sent to the distillation device 4 for concentration and crystallization, and the MgI2-nH2O and MgSO4-nH2O crystals obtained are sent to the hydrolysis carbonation reactor 5, while CO2 and water vapor are introduced for hydrolysis carbonation reaction, and the reaction temperature is controlled at 220°C, and finally HI steam and product MgCO3 are obtained; the chemical reaction formula of the reaction is as follows: MgI2+H2O+CO2=MgCO3+2HI.

[0055] The generated HI gas is sent to the HI catalytic decomposition reactor, where it is reacted at 500°C, and the generated I2 and HI are washed out in the condensation tower, and the hydrogen is output as a product, and the iodine-containing liquid is returned to the Bunsen reactor 1 for the next cycle. The MgSO4.nH2O crystal and MgCO3 solid mixture is filtered and washed in the MgSO4 dissolver 6 to obtain the by-product MgCO3, and the MgSO4 is sent to the MgSO4 decomposer 7, where the following reaction occurs at 1000°C: 2MgSO4 = 2MgO + 2SO2 + O2. The generated SO2 and O2 (molar flow 2:1) are sent to the distillation device 4 to provide part of the energy for the concentration crystallization of the mixture liquid, and the MgO solid is sent to the hydrolysis carbonation reactor 5, where the following reaction occurs at 220°C: MgO + CO2 = MgCO3. The generated MgCO3 is processed and output as a by-product.

[0056] Although the embodiments of the present application have been shown and described above, it is to be understood that the above-described embodiments are exemplary only, and are not to be taken as limiting the present application. Various changes and modifications can be made to the present application without departing from the spirit and scope of the present application, and all such changes and modifications are intended to fall within the scope of the present application.

Claims

1. A method for hydrogen production with simultaneous carbon dioxide mineralization in a thermochemical sulfur-iodine cycle, characterized by: The method comprises (S1), I2, SO2, H2O occurs Bunsen reaction and generates a mixed solution, the mixed solution reacts with magnesium silicate mineral to generate MgI2, MgSO4 and SiO2, wherein SiO2 is filtered and output as a byproduct, the Bunsen reaction is carried out at 20-120 DEG C, 1-2 atm, and the reaction temperature of the mixed solution and the magnesium silicate mineral is controlled at 20-90 DEG C; (S2), the MgI2, MgSO4 solution is concentrated and crystallized to obtain MgI2.nH2O crystal and MgSO4.nH2O crystal; (S3), the MgI2.nH2O crystal and the MgSO4.nH2O crystal are reacted with the introduced CO2 and water vapor, the reaction temperature is controlled at 180-250 DEG C, the reaction MgI2 + H2O + CO2 = MgCO3 + 2HI occurs, the generated HI is discharged in the form of gas, the MgCO3 and the MgSO4.nH2O crystal are dissolved with water and then separated by filtration, and the collected MgCO3 is output as a byproduct; (S4), MgSO4 is decomposed at 1000-1200 DEG C to generate MgO, SO2 and O2, the generated high-temperature gas is used as a heat source for solution concentration in (S2), and the heat-exchanged and cooled gas returns to (S1) to participate in the Bunsen reaction; (S5), HI is decomposed to generate I2 and hydrogen, and the unreacted HI gas is sprayed and washed, the spraying liquid is from the mixed solution generated in (S1) Bunsen reaction, hydrogen is discharged as a product after washing, and the spraying washing liquid returns to (S1) to participate in the Bunsen reaction.

2. The method of hydrogen production with carbon dioxide mineralization by thermochemical sulfur-iodine cycle according to claim 1, characterized in that: The liquid phase reaction raw material in the Bunsen reaction of (S1) is from the liquid in (S5) spraying washing and water supplemented from outside.

3. The method of hydrogen production with carbon dioxide mineralization by thermochemical sulfur-iodine cycle according to claim 1, characterized in that: The MgO generated by the decomposition of MgSO4 in (S4) returns to (S3) to react with CO2 to generate MgCO3.

4. The method of hydrogen production with carbon dioxide mineralization by thermochemical sulfur-iodine cycle according to claim 1, characterized in that: The HI gas in (S5) is decomposed into I2 and H2 in the presence of a catalyst at 450-500 DEG C, I2 and unreacted HI are sprayed and washed, and hydrogen is output as a product.

5. The method of hydrogen production with carbon dioxide mineralization by thermochemical sulfur-iodine cycle according to claim 1, characterized in that: The magnesium silicate mineral is a natural ore.

6. The method of hydrogen production with carbon dioxide mineralization by thermochemical sulfur-iodine cycle according to claim 5, characterized in that: The natural ore is serpentine and / or olivine.

Images