Continuous operation method for real-time mineralization of carbon dioxide in water-gas shift process

Abstract

The invention relates to a continuous operation method for real-time mineralization of carbon dioxide in a water gas shift process, and the continuous operation method comprises the following steps: conveying water vapor and CO-containing synthesis gas into an n-stage series reactor filled with a catalyst filler, and carrying out a water gas shift reaction to generate H2 and CO2, n being greater than or equal to 1; carrying a silicate-containing absorbent and CO-containing synthesis gas into the reactor through the water vapor for mineralizing CO2 in real time, and continuously discharging a gas phase and a solid product after the reaction is finished; water-gas shift high-efficiency clean hydrogen production and high-efficiency mineralization and storage of a byproduct CO2 generated in the process are realized, and the CO2 conversion rate is preferably up to 88% or above; meanwhile, resource utilization of the silicate-containing industrial waste is realized, and the CO2 emission reduction cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide capture and storage technology, and in particular to a continuous operation method for carbon dioxide in a real-time mineralized water gas conversion process. Background Technology

[0002] Hydrogen energy is a widely used, zero-pollution clean energy source, and the green and efficient production of hydrogen is crucial for its future development. Currently, green hydrogen production processes (such as water splitting for hydrogen production) face challenges of low energy efficiency and high cost. However, the technology of producing hydrogen from fossil fuels through reforming still dominates the industry, with hydrogen primarily generated during the water-gas shift reaction. The water-gas shift reaction refers to the reaction of carbon monoxide and water vapor into hydrogen and carbon dioxide under high temperature and pressure and the action of a catalyst. The reaction equation is: CO + H₂O → H₂ + CO₂. This reaction produces 1 mol of H₂ while simultaneously generating 1 mol of CO₂ as a byproduct. This not only makes CO₂ emissions a critical issue that urgently needs to be addressed, but also, as a thermodynamic equilibrium reaction, CO₂ accumulation limits the upper limit of H₂ purity. Therefore, a CO₂ emission reduction system is urgently needed, and low-cost, environmentally friendly large-scale CO₂ capture and storage is one of its key technologies. This not only reduces carbon emissions to a certain extent but also promotes the reaction towards hydrogen production, thereby significantly improving the purity and yield of H₂.

[0003] The current mainstream CO2 sequestration approaches include: ① injecting the captured CO2 underground (such as in oil and gas fields, brackish water layers, etc.) and into the ocean, but this can easily lead to CO2 leakage, formation deformation, earthquakes, and ocean acidification; ② using adsorbents to absorb CO2, but this method requires an additional desorption operation after CO2 adsorption saturation to achieve CO2 regeneration. The reasonable storage and utilization of desorbed CO2 becomes another problem. In other words, the above methods do not truly achieve CO2 fixation and sequestration, and adsorbents have drawbacks such as high raw material costs and complex preparation processes.

[0004] CN103288048A discloses a moving bed continuous catalytic adsorption enhanced chemical loop reforming hydrogen production process, which uses CaO as an adsorbent for in-situ CO2 adsorption enhancement. After adsorption saturation, the adsorbent enters a regeneration reactor for high-temperature decomposition to produce CO2. Adsorption and regeneration are carried out alternately, thereby realizing calcium cycling and CO2 capture. However, CaO adsorbent has drawbacks such as high energy consumption for regeneration (regeneration temperature as high as 800-900℃), poor stability due to particle sintering at high temperature, and reactor damage caused by CaCO3 expansion, which hinder its large-scale industrial application.

[0005] CN103466546A discloses a medium-temperature pressure swing adsorption method for applying a bifunctional adsorbent to adsorption-enhanced steam reforming and water-gas shift reaction. It uses a mixture of hydrotalcite or hydrotalcite-like material with molecular sieve or activated carbon as the adsorbent. The adsorption / regeneration process can be achieved without heating or cooling, and the adsorbent regeneration rate is fast. However, this mixed adsorbent material has disadvantages such as high preparation difficulty and high cost.

[0006] However, based on the principle of CO2 fixation through mineral carbonation in geological processes, using natural silicate minerals as fixatives to react with CO2 can generate permanent and more stable carbonates, thus achieving large-scale CO2 capture and storage. The reaction formula for calcium silicate, for example, is: CaSiO3 + CO2 → CaCO3 + SiO2. Furthermore, alkaline silicates exist in nature as ores such as wollastonite, while in industry they exist as industrial solid wastes such as waste cement, slag, and coal ash generated from building demolition, blast furnaces, and coal-fired power generation. The reserves of silicate raw materials suitable for CO2 mineral carbonation fixation far exceed those of fossil fuels, fully meeting the absorption needs of emitted CO2. In addition, CO2 mineralization can return industrial solid waste to the natural environment without pollution, and can even be used in cement auxiliary gel materials (SCM) to generate added value and achieve resource utilization. However, this reaction is very slow under normal temperature, pressure, and dry conditions. Accelerating the reaction requires high temperature, high pressure, and high humidity environments, which consume a large amount of energy, hindering the commercialization of this technology.

[0007] CN114751372A discloses a method for fixing carbon dioxide in a water-gas shift reaction (SFR) using silicate in real-time carbonization. This method utilizes the high temperature, high pressure, and high humidity environment of the SFR, using natural silicate minerals as CO2 fixatives during the SFR process. CO2 is absorbed in situ to promote the forward hydrogen production reaction, reducing CO2 emissions and improving hydrogen purity and yield. However, due to the long lifespan of the SFR catalyst and the rapid decay of the silicate carbonate reaction rate over time due to the thickening of the product layer, the silicate needs to be frequently separated from the SFR catalyst. This intermittent operation hinders its large-scale industrial application to some extent.

[0008] Therefore, developing a continuous operation method for carbon dioxide in the mineralized water-gas conversion process, achieving efficient separation and removal of CO2 during the reaction, and ensuring continuous discharge of silicate powder that gradually deactivates during the reaction, is of great significance for reducing carbon emissions and large-scale industrialization of clean energy production. Summary of the Invention

[0009] To solve the above-mentioned technical problems, this invention introduces a silicate-containing absorbent into a reactor via a mixture of water vapor and CO-containing syngas. The water-gas shift reaction and the CO2 mineralization reaction are integrated in the same reactor, realizing real-time CO2 mineralization during the water-gas shift process. Furthermore, the gaseous and solid products can be continuously discharged without the need to separate the silicate-containing absorbent and catalyst packing, thus meeting the requirements for continuous operation and achieving real-time and efficient carbon dioxide sequestration during the water-gas shift process.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] This invention provides a continuous operation method for carbon dioxide in a real-time mineralized water gas conversion process, the continuous operation method comprising the following steps:

[0012] Water vapor and CO-containing syngas are transported to an n-stage series reactor filled with catalyst packing to carry out a water-gas shift reaction to generate H2 and CO2, where n≥1 (e.g., 1, 3, or 5, etc.); and a silicate absorbent is carried into the reactor by the water vapor and CO-containing syngas for real-time CO2 mineralization. After the reaction is completed, the gas phase and solid products are continuously discharged.

[0013] This invention utilizes the reaction gas from the water-gas shift process (i.e., the reaction gas from the CO-containing syngas) to carry a silicate-containing absorbent into a reactor. This allows the water-gas shift and carbon dioxide mineralization to occur simultaneously in the same reactor, achieving real-time mineralization and preservation of CO2 generated during the water-gas shift process. Furthermore, the gaseous and solid products are continuously discharged after the reaction. Compared to traditional hydrogen production and carbon fixation methods, the continuous method described in this invention breaks through the thermodynamic equilibrium of the water-gas shift process to obtain high-purity H2. Real-time mineralization improves the conversion rate of CO2 preservation, and it eliminates the need for frequent separation of the absorbent and catalyst, enabling continuous operation.

[0014] The silicate absorbent described in this invention is a solid phase.

[0015] Preferably, the water vapor, CO-containing syngas, and silicate-containing absorbent described in this invention are introduced from the bottom up into the inlet of the first-stage reactor in an n-stage series reactor, rather than introducing water vapor, CO-containing syngas, and silicate-containing absorbent into each stage reactor.

[0016] Preferably, the volume percentage of CO in the CO-containing syngas is 10% to 90%, for example, it can be 10%, 30%, 40%, 50%, 70% or 90%.

[0017] The CO-containing syngas described in this invention originates from the tail gas produced by a gasifier of petrochemical raw materials such as pulverized coal, and also includes gases such as N2, CO2, and H2.

[0018] Preferably, the molar ratio of water vapor to CO in the CO-containing syngas is ≥1, for example, it can be 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8 or 3, preferably 2 to 3.

[0019] The present invention further preferably uses a molar ratio of water vapor to CO in the CO-containing syngas of 2 to 3, which is beneficial to the forward progress of the water-gas shift hydrogen production reaction, thereby improving the purity of hydrogen production and the carbon dioxide mineralization effect. If the molar ratio of water vapor to CO in the CO-containing syngas is too small, it will lead to a decrease in the purity of hydrogen production and a decrease in CO2 conversion rate. If the molar ratio of water vapor to CO in the CO-containing syngas is too large, it will lead to an increase in water vapor consumption.

[0020] Preferably, the flow rate of the water vapor and the CO-containing synthesis gas is 0.1 to 10 m / s, for example, it can be 0.1 m / s, 0.127 m / s, 0.325 m / s, 0.500 m / s, 0.847 m / s, 1 m / s, 3 m / s, 5 m / s, 7 m / s or 10 m / s.

[0021] Preferably, the inlet temperature of the water vapor and CO-containing synthesis gas entering the first-stage reactor is 100-600°C, for example, it can be 100°C, 200°C, 300°C, 400°C, 500°C or 600°C, and more preferably 200-450°C.

[0022] Preferably, the reactor comprises a filled fluidized bed and / or a gas-solid trickle bed.

[0023] Based on the different deactivation cycles of the hydrogen production catalyst packing and the silicate-containing absorbent, the reactor of the present invention operates both intermittently and continuously, respectively. It also utilizes the mutually beneficial characteristics of packed bed and fluidized bed. Fluidized bed particles can enhance the transfer rate in the packed bed, while the packing improves the uniformity of the fluidized bed particle distribution as an internal component.

[0024] Preferably, during the process of transporting the water vapor and CO-containing syngas to the n-stage series reactor, heat exchange is also carried out between each two adjacent reactor stages via a heat exchanger, where n≥2.

[0025] Optionally, during the process of transporting the water vapor and CO-containing syngas to the n-stage series reactors, heat exchange occurs through heat exchange tubes in each stage reactor, where n≥1.

[0026] It is worth noting that since both water-gas shift and carbon dioxide mineralization are exothermic reactions, temperature control is required to ensure the activity of the water-gas shift catalyst. This necessitates that, regardless of whether the water-gas shift reaction is carried out in a multi-stage adiabatic reactor or a single-stage isothermal reactor (equipped with heat exchange tubes), sufficient residence time and timely heat exchange must be ensured when selecting the height of each reactor stage. Otherwise, excessively high temperatures will lead to catalyst deactivation. Therefore, this invention does not impose any other specific restrictions on the height of the reactor, as long as the reaction temperature meets the upper limit requirement.

[0027] Preferably, the catalyst packing includes structured packing and / or particulate packing.

[0028] Preferably, the structure of the structured packing includes any one or a combination of at least two of honeycomb packing, corrugated metal plate packing, or open-cell foam packing, wherein typical but non-limiting combinations include a combination of honeycomb packing and corrugated metal plate packing, a combination of honeycomb packing and open-cell foam packing, or a combination of corrugated metal plate packing and open-cell foam packing, etc.

[0029] Preferably, the particulate packing includes spherical packing and / or non-spherical packing, with non-spherical packing being more preferred.

[0030] Preferably, the particle size of the granular filler is larger than the particle size of the silicate absorbent.

[0031] Preferably, the solid content ε of the spherical packing is... p It ranges from 0 to 0.7, for example, it can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.62, or 0.7, etc.

[0032] Preferably, the diameter of the spherical packing is 100 to 10000 μm, for example, it can be 100 μm, 300 μm, 500 μm, 1000 μm, 3000 μm, 5000 μm, 8000 μm or 10000 μm.

[0033] Preferably, the solid content ε of the non-spherical packing is... p It can be 0 to 0.5, for example, it can be 0, 0.1, 0.2, 0.3, 0.4 or 0.5, etc.

[0034] Preferably, the non-spherical packing includes Raschig ring packing and / or rectangular saddle ring packing, with rectangular saddle ring packing being the most preferred.

[0035] The rectangular saddle ring packing has an open structure, which is more conducive to the uniform distribution of silicate absorbent powder.

[0036] The solid content ε of the present invention p This refers to the volume percentage of the catalyst packing material in the packed bed.

[0037] The catalyst packing described in this invention further adopts non-spherical packing, and more preferably rectangular saddle ring packing, so as to alleviate the phenomenon of sedimentation and blockage of the packed bed during the transportation of silicate absorbent powder, which is conducive to achieving a higher solid content of silicate absorbent powder under a lower pressure drop.

[0038] Preferably, the temperature of the water-gas shift reaction is 100-600℃, for example, it can be 100℃, 200℃, 300℃, 400℃, 500℃ or 600℃.

[0039] Preferably, the pressure of the water-gas shift reaction is ≥1 atm, for example, it can be 1 atm, 5 atm, 10 atm or 15 atm, etc.

[0040] Preferably, the silicate-containing absorbent includes silicate-containing minerals and / or silicate-containing solid waste.

[0041] Preferably, the silicate-containing mineral includes any one or a combination of at least two of wollastonite, anorthite, or calcite, such as a combination of wollastonite and anorthite, a combination of wollastonite and calcite, or a combination of anorthite and calcite.

[0042] Preferably, the silicate-containing solid waste includes any one or a combination of at least two of silicate-containing waste cement, silicate-containing slag, or silicate-containing coal ash. For example, it may be a combination of silicate-containing waste cement and silicate-containing slag, a combination of silicate-containing slag and silicate-containing coal ash, or a combination of silicate-containing waste cement and silicate-containing coal ash, etc.

[0043] The silicate absorbent described in this invention preferably uses silicate-containing minerals and / or silicate-containing solid waste, so that industrial waste containing alkaline silicates such as waste gas cement, slag, and fly ash, as well as minerals containing alkaline silicates, can be utilized to generate added value and indirectly reduce CO2 emission reduction costs (such as the energy consumption and electricity costs of silicate grinding).

[0044] Preferably, the contact mode between the silicate absorbent and the mixture of water vapor and CO-containing syngas includes co-current contact and / or counter-current contact.

[0045] Preferably, the silicate absorbent is first crushed to obtain silicate absorbent powder, and then transported to the reactor via water vapor and CO-containing syngas.

[0046] Preferably, the particle size of the silicate absorbent powder is ≤100μm, for example, it can be 100μm, 90μm, 80μm, 70μm, 60μm, 50μm, 40μm, 30μm, 20μm or 10μm, and more preferably ≤25μm.

[0047] The present invention further preferably uses silicate absorbent powder with a particle size ≤25μm, which facilitates its easier transport into the voids of the reactor filled with catalyst packing, and improves the diffusion-controlled reactivity of the silicate absorbent powder. This is beneficial for the real-time mineralization of CO2 in the water-gas shift reaction process and improves the CO2 conversion rate. If the particle size of the silicate absorbent powder is too large, it will cause blockage of the voids in the reactor, resulting in low reactivity of the silicate absorbent powder, which will lead to insufficient real-time mineralization reaction and poor CO2 mineralization and storage effect.

[0048] Preferably, the solid content ε of the silicate absorbent powder is... s The value is 0 to 0.25, for example, it can be 0, 0.005, 0.1, 0.12, 0.15, 0.18, 0.20, 0.22 or 0.25, etc., preferably 0.12 to 0.25.

[0049] When the catalyst packing material is spherical packing material, the solid content ε of the silicate absorbent powder is... s Preferably, the solid content ε of the silicate absorbent powder is 0.06 to 0.1. When the catalyst packing is preferably a non-spherical packing, the solid content ε of the silicate absorbent powder is... s The preferred value is 0.12–0.25, which is beneficial for improving the purity of hydrogen produced by water-gas shift reaction and the CO2 mineralization conversion rate, and also allows for maintaining a low pressure drop within the packed bed; for spherical packing, if ε s <0.06, its hydrogen production purity and CO2 mineralization effect are poor; if ε s If ε > 0.1, sedimentation and blockage will occur, leading to an ultra-high pressure drop inside the reactor; for non-spherical packing, if ε s A value <0.12 will lead to insufficient water-gas shift reaction and CO2 mineralization, resulting in a decrease in hydrogen purity and CO2 mineralization conversion rate; if ε s >0.25, the hydrogen production purity and CO2 mineralization effect were not significantly improved, but instead an ultra-high pressure drop was generated in the reactor.

[0050] The solid content ε of the silicate absorbent powder of the present invention s This refers to the volume percentage of silicate absorbent powder filling the voids in the fluidized bed.

[0051] Preferably, the solid product comprises calcium carbonate, silica gel, and unreacted silicate.

[0052] Preferably, the solid product is recycled for use as a silicate-containing absorbent.

[0053] Preferably, the number of times the cycle is reused is greater than or equal to 1, for example, it can be 1, 2, 3, 4 or 5.

[0054] As a further preferred technical solution of the present invention, refer to Figure 1 The process flow shown includes the following steps in the continuous operation method:

[0055] Under pressure ≥1 atm, water vapor at 100–600℃ and syngas containing 10%–90% CO are transported at a flow rate of 0.1–10 m / s to an n-stage series reactor filled with catalyst packing to carry out a water-gas shift reaction, producing H2 and CO2, where n≥1; and the crushed particles with a particle size ≤100μm and a solid content ε s A silicate absorbent powder with a concentration of 0 to 0.25 is carried into the reactor by the water vapor and CO-containing syngas for real-time CO2 mineralization. After the reaction is completed, the gaseous phase and solid products are continuously discharged.

[0056] Wherein, the molar ratio of water vapor to CO in the CO-containing syngas is ≥1; the catalyst packing includes spherical packing and / or non-spherical packing; the non-spherical packing includes Raschig ring packing and / or rectangular saddle ring packing; the number of times the solid product is recycled as a silicate-containing absorbent is ≥1.

[0057] Figure 1 The intermediate gas mixture is a mixture of water vapor and CO-containing syngas.

[0058] Compared with the prior art, the present invention has at least the following beneficial effects:

[0059] The present invention provides a continuous operation method for real-time mineralization of carbon dioxide in a water-gas shift reaction process. This method utilizes a mixture of water vapor and CO-containing syngas to carry a silicate absorbent into the reactor of the water-gas shift reaction, achieving real-time mineralization of CO2 during the water-gas shift hydrogen production process. The CO2 conversion rate is preferably as high as 88% or more, and both the gaseous and solid products can be continuously discharged from the reactor outlet without separating the silicate absorbent used for CO2 mineralization from the catalyst used for water-gas shift, making clean hydrogen production and carbon fixation more efficient. Simultaneously, it enables the resource utilization of industrial waste containing alkaline silicates, such as waste cement, slag, and fly ash, generating added value and indirectly reducing CO2 emission reduction costs. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the continuous operation method for carbon dioxide in the real-time mineralized water gas conversion process provided by the present invention;

[0061] Figure 2 This invention provides a schematic diagram of a 5-stage series reactor in the continuous operation method for carbon dioxide in the real-time mineralized water gas conversion process, and a distribution diagram of the mole fraction (y) of CO and CO2 along the reactor height (z / m) in each stage of the continuous operation method provided in Examples 1 and 5-6. Among them, (a) is a schematic diagram of a 5-stage series reactor, and (b), (c) and (d) are distribution diagrams of the mole fraction (y) of CO and CO2 along the reactor height (z / m) in each stage of the reactor in Examples 1, 5 and 6, respectively.

[0062] Figure 3 This invention provides a schematic diagram of a 5-stage series reactor in the continuous operation method for carbon dioxide in the real-time mineralized water gas conversion process, and a distribution diagram of the mole fraction (y) of CO and CO2 along the reactor height (z / m) in each stage of the continuous operation method provided in Examples 1 and 11-12. Among them, (a) is a schematic diagram of a 5-stage series reactor, and (b), (c) and (d) are distribution diagrams of the mole fraction (y) of CO and CO2 along the reactor height (z / m) in each stage of the reactor in Examples 1, 11 and 12, respectively.

[0063] Figure 4 This is a graph showing the trend of CO2 emission reduction cost of the continuous operation method for carbon dioxide in the real-time mineralized water gas conversion process provided by the present invention, as well as the solid content of silicate powder and the number of recycling cycles.

[0064] Figure 5 This is a graph showing the trend of CO2 emission reduction added value of the continuous operation method for carbon dioxide in the real-time mineralized water gas conversion process provided by the present invention, as well as the solid content of silicate powder and the number of recycling cycles. Detailed Implementation

[0065] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0066] For ease of experimental comparison, the following examples and comparative examples use a 5-stage series reactor as an example, wherein the first to fourth stage reactors use a high-temperature catalyst Fe2O3 / Cr2O3 / CuO, specifically in the ratio of 90wt% Fe2O3, 7wt% Cr2O3 and 3wt% CuO, and the fifth stage reactor uses a low-temperature catalyst CuO / ZnO / Al2O3 (Sud-Chemie, catalyst EX-2248). However, other catalyst components suitable for water-gas shift processes can also be used in this invention.

[0067] I. Implementation Examples

[0068] Example 1

[0069] This embodiment provides a continuous operation method for carbon dioxide in a real-time mineralized water gas conversion process, the continuous operation method including the following steps:

[0070] Under a pressure of 54.28 atm, water vapor at 200℃ and syngas containing 40% CO (18% CO2, 39% H2, and 3% N2) are transported at a flow rate of 0.1271 m / s to a five-stage series reactor filled with catalyst packing for a water-gas shift reaction. Between each adjacent two-stage reactor, heat exchangers are used to cool the mixture to 200℃, generating H2 and CO2. The crushed gas has a particle size of 10 μm and a solid content ε... s Wollastonite powder with a concentration of 0.15 is carried into the reactor by the water vapor and CO-containing syngas for real-time CO2 mineralization. After the reaction is completed, the gaseous phase and solid products are continuously discharged.

[0071] The molar ratio of water vapor to CO in the CO-containing syngas is 2.3; the catalyst packing is a rectangular saddle ring packing with a solid content ε. p The particle size is 0.344, and the particle size is 6300μm; and the heights of each reactor from bottom to top are 1m, 2.5m, 4.5m, 14m and 16m respectively.

[0072] The composition (expressed in oxide form) and corresponding contents of wollastonite used in this embodiment are shown in Table 1.

[0073] Table 1

[0074] Components CaO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> Content / mol% 50 50 0

[0075] Example 2

[0076] This embodiment provides a continuous operation method for carbon dioxide in a real-time mineralized water gas conversion process, the continuous operation method including the following steps:

[0077] Under a pressure of 25 atm, water vapor at 150°C and syngas containing 50% CO (15% CO2, 32% H2, and 3% N2) are fed at a flow rate of 0.2252 m / s into a five-stage series reactor filled with catalyst packing for a water-gas shift reaction. Between each adjacent two-stage reactor, heat exchangers are used to cool the mixture to 180°C, generating H2 and CO2. The crushed gas has a particle size of 25 μm and a solid content ε... s Waste cement powder containing silicates with a concentration of 0.25 is carried into the reactor by the water vapor and CO-containing syngas for real-time CO2 mineralization. After the reaction is completed, the gas phase and solid products are continuously discharged.

[0078] The molar ratio of water vapor to CO in the CO-containing syngas is 2.5; the catalyst packing is a rectangular saddle ring packing with a solid content ε. p The particle size is 0.344, and the particle size is 6300μm; and the heights of each reactor from bottom to top are 3.5m, 7m, 20m, 6.5m and 1m respectively.

[0079] The composition and corresponding content of the silicate-containing waste cement used in this embodiment are shown in Table 2.

[0080] Table 2

[0081]

[0082]

[0083] Example 3

[0084] This embodiment provides a continuous operation method for carbon dioxide in a real-time mineralized water gas conversion process, the continuous operation method including the following steps:

[0085] Under a pressure of 25 atm, water vapor at 250℃ and syngas containing 30% CO (20% CO2, 42% H2, and 8% N2) are transported at a flow rate of 0.15 m / s to a five-stage series reactor filled with catalyst packing for a water-gas shift reaction. Between each adjacent two-stage reactor, heat exchangers are used to cool the mixture to 200℃, generating H2 and CO2. The crushed gas with a particle size of 20 μm and a solid content ε... s The silicate-containing coal ash powder with a concentration of 0.2 is carried into the reactor by the water vapor and CO-containing syngas for real-time CO2 mineralization. After the reaction is completed, the gas phase and solid products are continuously discharged.

[0086] The molar ratio of water vapor to CO in the CO-containing syngas is 2; the catalyst packing is Raschig ring packing with a solid content ε. p The particle size is 0.29, and the particle size is 3000μm; and the heights of each reactor from bottom to top are 3.5m, 7m, 20m, 6.5m and 1m respectively.

[0087] The composition and corresponding content of silicate-containing coal ash used in this embodiment are shown in Table 3.

[0088] Table 3

[0089] Components CaO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> Content / mol% 37.5 47.5 15

[0090] Example 4

[0091] This embodiment provides a continuous operation method for carbon dioxide in a real-time mineralized water gas conversion process, the continuous operation method including the following steps:

[0092] Under a pressure of 100 atm, water vapor at 250℃ and syngas containing 60% CO (9% CO2, 29% H2, and 2% N2) are fed at a flow rate of 0.1 m / s into a 5-stage series reactor filled with catalyst packing for a water-gas shift reaction. Between each adjacent two-stage reactor, heat exchangers are used to cool the mixture to 200℃, generating H2 and CO2. The crushed gas with a particle size of 10 μm and a solid content ε... s Silicate-containing slag powder with a concentration of 0.1 is carried into the reactor by the steam and CO-containing syngas for real-time CO2 mineralization. After the reaction is completed, the gas phase and solid products are continuously discharged.

[0093] The molar ratio of water vapor to CO in the CO-containing syngas is 3; the catalyst packing is spherical packing with a solid content ε. p The particle size is 0.62, the particle size is 10000μm, and the heights of the reactors from bottom to top are 2m, 4m, 15m, 14m and 3m respectively.

[0094] The composition (expressed in oxide form) and corresponding content of the silicate-containing slag used in this embodiment are shown in Table 4.

[0095] Table 4

[0096] Components CaO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> Content (mol%) 50 37.5 12.5

[0097] Example 5

[0098] This embodiment provides a continuous operation method for carbon dioxide in a real-time mineralized water gas conversion process. The continuous operation method is the same as in Embodiment 1, except that the rectangular saddle ring packing is replaced with Raschig ring packing.

[0099] Example 6

[0100] This embodiment provides a continuous operation method for carbon dioxide in a real-time mineralized water gas conversion process. The continuous operation method is the same as in Embodiment 1, except that the rectangular saddle ring packing is replaced with spherical packing.

[0101] Example 7

[0102] This embodiment provides a continuous operation method for carbon dioxide in a real-time mineralized water-gas shift process, except for the solid content ε of the wollastonite powder. s Except for 0.1, everything else is the same as in Example 1.

[0103] Example 8

[0104] This embodiment provides a continuous operation method for carbon dioxide in a real-time mineralized water-gas shift process, except for the solid content ε of the wollastonite powder. sExcept for 0.26, everything else is the same as in Example 1.

[0105] Example 9

[0106] This embodiment provides a continuous operation method for carbon dioxide in a real-time mineralized water gas shift process, except for the solid content ε of the silicate slag powder. s Except for 0.05, everything else is the same as in Example 4.

[0107] Example 10

[0108] This embodiment provides a continuous operation method for carbon dioxide in a real-time mineralized water gas shift process, except for the solid content ε of the silicate slag powder. s Except for 0.15, everything else is the same as in Example 4.

[0109] Example 11

[0110] This embodiment provides a continuous operation method for carbon dioxide in a real-time mineralized water gas conversion process. Except for the particle size of the wollastonite powder being 38 μm, the continuous operation method is the same as in Embodiment 1.

[0111] Example 12

[0112] This embodiment provides a continuous operation method for carbon dioxide in a real-time mineralized water gas conversion process. Except for the particle size of the wollastonite powder being 75 μm, the continuous operation method is the same as in Embodiment 1.

[0113] Example 13

[0114] This embodiment provides a continuous operation method for carbon dioxide in a real-time mineralized water gas conversion process. Except that the molar ratio of water vapor to CO in the CO-containing syngas is 1, the rest is the same as in Embodiment 1.

[0115] Example 14

[0116] This embodiment provides a continuous operation method for carbon dioxide in a real-time mineralized water gas conversion process. Except for the molar ratio of water vapor to CO in the CO-containing syngas being 3.5, all other aspects are the same as in Embodiment 1.

[0117] II. Comparative Example

[0118] Comparative Example 1

[0119] This comparative example provides an intermittent operation method for carbon dioxide in a mineralized water gas conversion process, using the method steps disclosed in Example 1 of CN114751372A to carry out a 1-hour reaction.

[0120] III. Tests and Results

[0121] ① The molar fraction distribution of CO and CO2 in the five-stage series reactors of Examples 1 and 5-6 were tested, and the results are as follows: Figure 2 As shown;

[0122] Depend on Figure 2 It can be seen that (b), (c), and (d) are the distribution diagrams of the molar fraction (y) of CO and CO2 along the reactor height (z / m) in each stage of the reactor when the packing structure is a rectangular saddle ring (Example 1), a Raschig ring (Example 5), and a ball (Example 6), respectively. The comparison shows that the molar fraction of CO in the 5th stage reactor is almost 0, but the molar fraction of CO2 is significantly different. When the catalyst packing is a rectangular saddle ring packing, the molar fraction of CO2 is the lowest. It can be seen that the CO2 mineralization degree in the packed bed of the rectangular saddle ring packing is relatively large.

[0123] ② The mole fraction distribution of CO and CO2 in the five-stage series reactors of Examples 1 and 11-12 was tested, and the results are as follows: Figure 3 As shown;

[0124] Depend on Figure 3 It can be seen that: (a) is a schematic diagram of the 5-stage series reactor used in all the above embodiments; (b), (c) and (d) are the distribution diagrams of the molar fraction (y) of CO and CO2 in each stage reactor along the reactor height (z / m) when the particle size of the wollastonite powder is 10 μm (Example 1), 38 μm (Example 11) and 75 μm (Example 12), respectively. It can be seen that: as the particle size of the wollastonite powder increases from 10 μm to 38 μm, and then further to 10 μm, the molar fraction of CO in the 5th stage reactor gradually increases, and the molar fraction of CO2 gradually increases; when the particle size is 10 μm, the molar fraction of CO2 in the 5th stage reactor is almost 0. It can be seen that as the particle size of the silicate powder decreases, the degree of CO2 mineralization increases.

[0125] ③ Test the purity of H2 and the total pressure drop of the reactor obtained by the above examples and comparative examples, and calculate the CO2 conversion rate according to the following formulas (1) and (2). The results are shown in Table 5.

[0126]

[0127] Among them, X CO X represents the conversion rate of CO. CO2 y represents the CO2 conversion rate. CO,in y represents the CO mole fraction at the reactor inlet; CO y represents the CO mole fraction distributed along the reactor height. CO2,in y represents the CO2 mole fraction at the reactor inlet; CO2 γ represents the CO2 mole fraction distributed along the reactor height; γ is γ = yN2,in / y N2 The compression ratio resulting from the consumption of CO2 due to mineralization of CO2 is expressed as N2. The mole fraction distributed along the reactor height is converted to the mole fraction at the reactor inlet when CO2 is not consumed.

[0128] Table 5

[0129] project <![CDATA[Purity of H2 / %]]> <![CDATA[CO2 conversion rate / %]]> Total voltage drop / atm Example 1 95 98 2.63 Example 2 88 88 5.09 Example 3 60 18 1.02 Example 4 67 39 38 Example 5 67 41 0.92 Example 6 78 69 207 Example 7 90 91 1.94 Example 8 96 99 5.13 Example 9 59 13 8.15 Example 10 86 82 177 Example 11 68 44 2.55 Example 12 60 22 2.41 Example 13 78 76 2.61 Example 14 95 99 2.67 Comparative Example 1 43 0 44

[0130] As can be seen from Table 5:

[0131] (1) As can be seen from Examples 1 to 4, the continuous operation method of the present invention integrates the water-gas shift reaction and CO2 mineralization in the same reactor, and selects the method of using water vapor and CO-containing syngas to carry silicate absorbent powder into the reactor, which avoids the accumulation of solid products in the reactor and the inability of the reaction to continue. There is no need to separate the catalyst packing and the silica-containing powder absorbent, thus realizing the real-time mineralization of CO2 in the water-gas shift process and the continuous operability of the method; and the purity of the H2 produced is as high as 60% or more, and the conversion rate of CO2 is as high as 18% or more.

[0132] (2) As can be seen from Examples 1 and 5-6, compared with Example 1, the hydrogen purity of the catalyst packing in Example 5 decreased to 67% and the CO2 conversion rate decreased to 41% due to the use of Raschig ring packing, but the pressure drop was still maintained at 0.92 atm; the hydrogen purity of the catalyst packing in Example 6 decreased to 78% and the CO2 conversion rate decreased to 69%, and the pressure drop increased to 207 atm. It can be seen that the present invention further prefers non-spherical packing, which reduces the pressure drop in the reaction process; and even more preferably rectangular saddle ring packing, which greatly improves the hydrogen purity and CO2 mineralization conversion rate of water-gas shift reaction, while maintaining a low pressure drop.

[0133] (3) As can be seen from Examples 1 and 7-8, compared with Example 1, the solid content ε of the wollastonite powder in Example 7 is higher. s The low solids content (ε) of the wollastonite powder in Example 8 resulted in a decrease in hydrogen purity to 90% and CO2 conversion rate to 91%. s A high solid content ε does not significantly improve performance and may even lead to higher energy consumption. Therefore, when using rectangular saddle ring packing, the preferred solid content ε of the silicate absorbent powder is... s With a concentration of 0.12–0.25, it achieves relatively excellent hydrogen production and CO2 mineralization effects, and has a low pressure drop.

[0134] (4) As can be seen from Examples 4 and 9-10, compared with Example 4, the solid content ε of the silicate slag powder in Example 9 is higher. s The low purity resulted in a hydrogen production purity of only 59% and a CO2 conversion rate of only 13%; while the solid content ε of the silicate-containing slag powder described in Example 10 was... s The pressure drop is too high; although the hydrogen purity and CO2 conversion rate are significantly improved, the total pressure drop is as high as 177 atm. This indicates that when using spherical packing material in this invention, the solid content ε of the silicate absorbent powder is preferred. s With a pressure drop of 0.06 to 0.1, high hydrogen purity and CO2 mineralization effect are achieved while ensuring a low pressure drop.

[0135] (5) As can be seen from Examples 1 and 11-12, compared with Example 1, the particle size of the wollastonite powder in Examples 11 and 12 is relatively large, resulting in the purity of H2 decreasing to below 68% and the conversion rate of CO2 decreasing to below 44%. This indicates that the present invention further prefers the particle size of the silicate powder to be ≤25μm, which further improves the purity of the obtained H2 and the conversion rate of CO2, resulting in better CO2 mineralization and storage effect.

[0136] (6) As can be seen from Examples 1 and 13-14, compared with Example 1, the molar ratio of water vapor to CO in CO-containing syngas in Example 13 is relatively small, resulting in a purity of only 78% for the produced H2 and a CO2 conversion rate of only 76%. In Example 14, the molar ratio of water vapor to CO in CO-containing syngas is relatively large, resulting in increased water vapor consumption, but the purity of the produced H2 is still 95%, and the CO2 conversion rate increases slightly from 98% to 99%. This indicates that the present invention further optimizes the molar ratio of water vapor to CO in CO-containing syngas to be 2-3, which further improves the purity of water-gas conversion hydrogen production and the energy efficiency ratio of CO2 mineralization conversion rate.

[0137] (7) As can be seen from Example 1 and Comparative Example 1, the method used in Comparative Example 1 still requires frequent separation of silicate and water-gas shift catalyst, and cannot achieve continuous operation. Within only 1 hour of operation, the silicate absorbent is already saturated, the CO2 conversion rate drops to close to 0, and the hydrogen production purity is also low.

[0138] ④ An economic analysis of the technical solution described in this invention is conducted, specifically analyzing the carbon dioxide emission reduction cost, the number of times the silicate absorbent is recycled (m), and its solid content (ε). s The relationship, the result is as follows Figure 4 as well as Figure 5 As shown;

[0139] Among them, the CO2 emission reduction cost M includes: reducing the particle size of silicate powder (d s Energy consumption (M) for grinding (including crushing and milling) to improve activity 研磨 ); Cost of absorbent (M) 吸收剂 The profit (M) of using the carbonation product of the absorbent, i.e., the solid product, as an auxiliary cement gelling material (SCM) to formulate low-carbon cement. 水泥 ); the direct CO2 emission reduction from water-gas shift reaction, the indirect CO2 emission reduction from SCM replacing part of traditional cement, and the CO2 carbon tax saved (M 碳税 The analysis is performed according to the parameters shown in Table 6 and the following calculation formula (3);

[0140] M = M 研磨 +M 吸收剂 -M 水泥 -M 碳税 (3)

[0141] Table 6

[0142]

[0143] Depend on Figure 4 and Figure 5 It can be seen that the cost of CO2 emission reduction is affected by the number of times the silicate powder is recycled (m) and its solid content (ε). s Constraints include the need to balance the recycling frequency and solids content of silicate powders to reduce CO2 emission reduction costs; overall, although M 研磨 +M 吸收剂 The sum of these costs means that the cost of CO2 emission reduction is relatively high compared to conventional carbon sequestration technologies. Figure 4 ), but M 水泥 +M 碳税 That is, the added value is also relatively high. Figure 5 The high profitability can offset the cost of carbon sequestration, thus the continuous operation method described in this invention meets the prerequisites for commercial application.

[0144] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A continuous method of operating a real-time mineralized water gas shift process for carbon dioxide, characterized in that, The continuous operation method comprises the following steps: water vapor and CO-containing synthesis gas are transported into n-stage reactors filled with catalyst packing to perform water gas shift reaction to generate H2 and CO2, wherein n≥1; and silicate-containing absorbent is carried into the reactors by the water vapor and CO-containing synthesis gas to mineralize CO2 in real time; after the reaction, gas phase and solid product are continuously discharged.

2. The continuously operated method according to claim 1, characterized in that The volume ratio of CO in the CO-containing synthesis gas is 10% to 90%; Preferably, the molar ratio of CO in the water vapor and CO-containing synthesis gas is ≥1, preferably 2 to 3; Preferably, the flow rate of the water vapor and CO-containing synthesis gas is 0.1 to 10 m / s; Preferably, the inlet temperature of the water vapor and CO-containing synthesis gas into the first reactor is 100 to 600 ℃, preferably 200 to 450 ℃.

3. The continuously operated method according to claim 1 or 2, characterized in that The reactor comprises a fluidized bed and / or a gas-solid trickle bed filled with the catalyst packing; Preferably, during the transportation of the water vapor and CO-containing synthesis gas into the n-stage reactors, heat exchange is performed between every two adjacent reactors through a heat exchanger, and n≥2.

4. The continuously operated process according to any one of claims 1 to 3, characterized in that The catalyst packing comprises structured packing and / or granular packing; Preferably, the structure of the structured packing comprises any one or a combination of at least two of honeycomb packing, corrugated metal plate packing or open-cell foam packing; Preferably, the granular packing comprises spherical packing and / or non-spherical packing, preferably non-spherical packing; Preferably, the non-spherical packing comprises Raschig ring packing and / or Gaur ring packing, preferably Gaur ring packing.

5. The continuously operated process according to any one of claims 1 to 4, characterized in that The temperature of the water gas shift reaction is 100 to 600 ℃; Preferably, the pressure of the water gas shift reaction is ≥1 atm.

6. The continuously operated process according to any one of claims 1 to 5, characterized in that The silicate-containing absorbent comprises silicate-containing minerals and / or silicate-containing solid waste; Preferably, the silicate-containing minerals comprise any one or a combination of at least two of wollastonite, anorthite or calcite; Preferably, the silicate-containing solid waste comprises any one or a combination of at least two of silicate-containing waste cement, silicate-containing slag or silicate-containing coal ash.

7. The continuously operated process according to any one of claims 1 to 6, characterized in that The contact mode of the silicate-containing absorbent with the mixed gas composed of the water vapor and CO-containing synthesis gas comprises co-current contact and / or counter-current contact.

8. The continuously operated process according to any one of claims 1 to 7, characterized in that The silicate-containing absorbent is first crushed to obtain silicate-containing absorbent powder, and then transported into the reactor by the water vapor and CO-containing synthesis gas; Preferably, the particle size of the silicate-containing absorbent powder is ≤100 μm, preferably ≤25 μm; Preferably, the solids content ε of the silicate-containing absorbent powder is s 0 to 0.25, preferably 0.12 to 0.

25.

9. The continuously operated process according to any one of claims 1 to 8, characterized in that, The solid product comprises calcium carbonate, silica gel and unreacted silicate; Preferably, the solid product is recycled and used as silicate-containing absorbent; Preferably, the recycling times m≥1.

10. The continuously operated process according to any one of claims 1 to 9, characterized in that, The continuous operation method comprises the following steps: Water vapor with temperature of 100-600 DEG C and 10-90% CO containing gas are transported into n-stage serial reactors filled with catalyst packing at flow rate of 0.1-10 m / s under pressure ≥1 atm to carry out water gas shift reaction, generating H2 and CO2, wherein n≥1; and the broken particles with particle size ≤100 μm and solid content ε s Silicate containing absorbent powder with 0-0.25 is carried into the reactor by the water vapor and CO containing gas to mineralize CO2 in real time, and the gas phase and solid product are continuously discharged after reaction. Preferably, the molar ratio of CO in the water vapor and CO-containing synthesis gas is ≥1; the catalyst packing comprises spherical packing and / or non-spherical packing; the non-spherical packing comprises Raschig ring packing and / or Gaur ring packing; and the recycling times m of the solid product used as silicate-containing absorbent is ≥1.

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