Monolithic catalyst packed bed process system for fluidized carbonate reduction

Abstract

According to the monolithic catalyst packed bed process system and the corresponding method for fluidized carbonate reduction based on the monolithic catalyst, by adopting the monolithic catalyst, full contact of a gas phase, a solid phase and a solid phase is guaranteed, the efficiency of carbonate reduction reaction is improved, and the utilization rate of the catalyst is increased. Meanwhile, the problem of separation of a subsequently generated oxide solid product and a catalyst solid is avoided, and continuous operation of the system is realized. According to the present invention, the heating decomposition reaction of the metal carbonate and the hydrogenation reduction reaction of the in-situ carbon dioxide are coupled, and the monolithic catalyst is adopted to perform catalysis so as to obtain the high-value metal oxide and the synthesis gas or methanol product, and compared with the prior art, the process reaction temperature is substantially reduced so as to easily promote energy saving and emission reduction.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy conservation, emission reduction and efficiency improvement in high-carbon emission industries. Specifically, it relates to an integrated catalyst packed bed process system for fluidized carbonate reduction. Background Art

[0002] Traditional manufacturing industries such as building materials, iron and steel, and non-ferrous metallurgy are the pillars and basic industries of the national economy. Through the carbon emission traceability analysis of the above industrial processes, it can be seen that the main source of high-carbon emissions lies in the production-type carbon emissions of carbon dioxide (CO2) inevitably produced by the high-temperature pyrolysis of carbonate ore raw materials and the high-temperature combustion-type carbon emissions of fossil fuels. Therefore, developing transformative negative-carbon technologies from the production source and reducing energy consumption are the core and key to solving the development problems of high-carbon emission industries using carbonate as industrial raw materials.

[0003] To develop transformative negative-carbon technologies from the production source, it is necessary to change the production process of calcining carbonate in the air. For example, carbonate can be used as a "white carbon" resource, and by introducing hydrogen-supplying gases (such as CH4, H2), the carbon in the carbonate can be reduced to high-value carbon-containing chemicals such as syngas and methanol. At the same time, metal oxide solids are obtained as reaction products. While completely eliminating CO2 emissions, metal oxide products and high-value carbon-containing chemicals can also be obtained, thereby significantly improving economic benefits. The key to the carbonate reduction reaction is the development of highly efficient catalysts. However, the related catalysts are often solids, and the addition of the catalysts makes the reaction system of hydrogen-supplying gas-carbonate-catalyst a complex gas-solid-solid three-phase reaction. In such a reaction system, on the one hand, the mixing effect of the solid carbonate and the catalyst will affect the reaction efficiency; on the other hand, the separation of the metal oxide solid, which is the reaction product, from the closely contacted catalyst also becomes a major difficulty. Therefore, there is still a need to develop a carbonate reduction and refining process with higher reaction efficiency or more convenient product separation. Summary of the Invention

[0004] Aiming at the defects of the prior art, the present invention provides an integrated catalyst packed bed process system for gas-solid-solid fluidized carbonate reduction based on an integrated catalyst, which can not only ensure efficient reaction during the contact of gas-solid-solid three phases, but also avoid the additional step of separating the metal oxide product from the solid catalyst, thereby realizing the efficient and continuous operation of this process and greatly improving the reaction efficiency.

[0005] In one aspect, the present invention provides an integrated catalyst packed bed process system for fluidized carbonate reduction. The system includes a carbonate reactor, a gas-solid product separation device, a gas-solid heat exchanger, and a solid product recovery unit, wherein,

[0006] The carbonate reactor is a fluidized bed reactor. The bottom of the reactor is the high-temperature gas inlet, the top is the product outlet, the side wall of the lower part of the reactor is provided with a carbonate feed inlet, a gas distribution plate is arranged below the carbonate feed inlet inside the reactor, and one or more integral catalyst units are arranged above the gas distribution plate;

[0007] The side wall of the upper part of the gas-solid product separation device is provided with a feed inlet, the top is the gas outlet, the bottom of the device is the solid material outlet, and this feed inlet is connected to the product outlet of the carbonate reactor through a pipeline;

[0008] The top of the gas-solid heat exchanger is the solid material inlet, the bottom is the low-temperature gas inlet, the side wall of the upper part is the high-temperature gas outlet, the side wall of the lower part is the solid product outlet, the solid material inlet is connected to the solid material outlet of the gas-solid product separation device through a pipeline, and the gas outlet is connected to the gas inlet of the carbonate reactor through a pipeline;

[0009] The solid product recovery unit is a receiving bin, which is connected to the solid product outlet of the gas-solid heat exchanger through a pipeline.

[0010] Preferably, the intervals between the integral catalyst units at all levels are the same or different. More preferably, the intervals between the integral catalyst units at all levels are 5 - 20 cm. Further preferably, the intervals between the integral catalyst units at all levels are 10 cm.

[0011] Preferably, the integral catalyst unit includes one or more layers of integral catalysts; preferably, the integral catalyst unit includes multiple layers of integral catalysts. More preferably, there is a heat exchange space between each layer of integral catalysts. The composition of the integral catalyst can be adjusted according to different reactions or reaction types; the number of layers of integral catalysts at all levels can be adjusted according to the reaction conversion efficiency.

[0012] In one or more embodiments, a mechanical oscillation device is provided on the outer wall of the carbonate reactor at the position corresponding to the integral catalyst unit.

[0013] In one or more embodiments, the integral catalyst is selected from one or more of a wire mesh catalyst, a plate catalyst, or a honeycomb catalyst.

[0014] Preferably, the integral catalyst is a wire mesh catalyst.

[0015] In one or more embodiments, the gas-solid product separation device is a cyclone separator; the receiving bin is connected to the cyclone separator. The receiving bin is used to collect the solid metal oxide product after heat exchange.

[0016] In one or more embodiments, the solid material inlet and the solid product outlet are connected to the shell side of the gas-solid heat exchanger, and the low-temperature gas inlet and the high-temperature gas outlet are connected to the tube side of the gas-solid heat exchanger. After the hydrogen supply gas is preheated by the gas-solid heat exchanger, it is input into the carbonate reactor through the high-temperature gas inlet.

[0017] In another aspect, the present invention provides a method for reducing fluidized carbonate, the method comprising the following steps:

[0018] S1: Raise the temperature in the carbonate reactor to the reaction temperature and adjust the pressure in the carbonate reactor to the reaction pressure;

[0019] S2: The carbonate raw material is input into the bottom of the carbonate reactor through the carbonate feed pipeline, and the hydrogen supply gas is input into the bottom of the carbonate reactor through the gas feed pipeline. After the hydrogen supply gas enters the carbonate reactor, it drives the carbonate particles to move upward together, so that the carbonate contacts the monolithic catalyst unit and reacts; wherein, the particle size of the carbonate input into the carbonate reactor is 30-60% of the pores or intervals of the monolithic catalyst.

[0020] S3: The reaction product is output through the product discharge pipeline at the top of the carbonate reactor and enters the gas-solid product separation device for separation;

[0021] S4: Collect the gas product output from the gas product discharge pipeline of the gas-solid product separation device; collect the solid product with the solid product recovery unit.

[0022] Preferably, the components of the monolithic catalyst are selected from one or more combinations of Cr, Ni, Fe, Cu, ZnO, Al2O3, and In2O3. More preferably, the components of the monolithic catalyst are selected from CrNi alloy, FeNi alloy, Cu / ZnO / Al2O3 composite and Al2O3.

[0023] In one or more embodiments, the hydrogen supply gas is selected from one or two of methane and hydrogen.

[0024] Preferably, the hydrogen supply gas is methane or hydrogen.

[0025] In one or more embodiments, the carbonate is selected from one or more of calcium carbonate, magnesium carbonate, ferrous carbonate, cobalt carbonate, nickel carbonate, chromium carbonate, cuprous carbonate, zinc carbonate, indium carbonate or aluminum carbonate.

[0026] Preferably, the particle size of the carbonate input into the carbonate reactor is 75-300 μm.

[0027] Preferably, the carbonate is selected from one or more of calcium carbonate, magnesium carbonate, and ferrous carbonate.

[0028] In one or more embodiments, the reaction temperature is 200 to 900 °C.

[0029] Preferably, the carbonate is calcium carbonate and the reaction temperature is 600 to 800 °C. More preferably, the carbonate is calcium carbonate and the reaction temperature is 650 to 750 °C.

[0030] Preferably, the carbonate is magnesium carbonate and the reaction temperature is 350 to 600 °C. More preferably, the carbonate is calcium carbonate and the reaction temperature is 400 to 500 °C.

[0031] Preferably, the carbonate is ferrous carbonate and the reaction temperature is 250 to 500 °C. More preferably, the carbonate is calcium carbonate and the reaction temperature is 300 to 400 °C.

[0032] In one or more embodiments, the reaction pressure is 0.05 to 6 Mpa.

[0033] Preferably, the hydrogen supply gas is hydrogen, the gas product is methanol, and the reaction pressure is 3.5 to 5.5 Mpa. More preferably, the hydrogen supply gas is hydrogen, the gas product is methanol, and the reaction pressure is 4 to 5 Mpa.

[0034] Preferably, the hydrogen supply gas is methane, the gas product is syngas, and the reaction pressure is 0.05 to 1 Mpa. More preferably, the hydrogen supply gas is methane, the gas product is syngas, and the reaction pressure is 0.08 to 0.2 Mpa.

[0035] In one or more embodiments, the solid product is a metal oxide.

[0036] Preferably, the metal oxide is selected from one or more of CaO, MgO, Fe2O3, Fe3O4, CoO, NiO, Cr2O3, ZnO, In2O3 or Al2O3.

[0037] In one or more embodiments, the gas product is selected from one or both of syngas and methanol.

[0038] Preferably, the hydrogen supply gas is methane and the gas product is syngas; preferably, the hydrogen supply gas is hydrogen and the gas product is methanol; preferably, the hydrogen supply gas is a mixture of hydrogen and methane and the gas product is a mixture of syngas and methanol.

[0039] The integrated catalyst packing bed process system and method for fluidized carbonate reduction provided by the present invention has at least one of the following beneficial effects:

[0040] 1. The present invention provides an integral catalyst packed bed process system and a corresponding method for fluidized carbonate reduction based on an integral catalyst. By using the integral catalyst, it not only ensures sufficient contact among the gas-solid-solid three phases, improves the efficiency of the carbonate reduction reaction, but also avoids the subsequent separation problem of the oxide solid product and the catalyst solid, realizing the continuous operation of the system.

[0041] 2. By adjusting the gap size inside the integral catalyst and the reaction gas velocity, or by setting integral catalyst units with multi-stage distribution, it is ensured that the carbonate particles stay in the catalytic reaction active region for sufficient time and achieve a relatively complete reaction of the carbonate particles (the carbonate conversion rate is greater than 80%, and can reach 99% after optimizing the conditions).

[0042] 3. By comparing integral catalysts with different structural forms, a wire mesh catalyst with relatively excellent carbonate conversion rate and product selectivity is preferably obtained.

[0043] 4. By adding a bin wall vibrator to the outer wall of the reactor, it is avoided that the material is blocked inside the catalytic bed layer, ensuring the smooth operation of the fluidized bed process system.

[0044] 5. By coupling the thermal decomposition reaction of metal carbonate and the hydrogenation reduction reaction of in-situ carbon dioxide, and using an integral catalyst for catalysis, high-value metal oxides and syngas or methanol products are obtained, and the process reaction temperature is significantly decreased compared with the prior art, which is beneficial to promoting energy conservation and emission reduction. Description of the Drawings

[0045] Figure 1 is the process flow diagram of integral catalyst promoted fluidized carbonate reduction. Among them, the light-colored particles in the carbonate reactor represent metal carbonate, and the dark-colored particles represent metal oxide.

[0046] Figure 2 is the structural diagram of the solid powder nozzle. Among them, "MeCO3" refers to metal carbonate.

[0047] Figure 3 is the structural diagram of the air distribution plate.

[0048] Description of the drawing numbers: 10 - carbonate reactor, 11 - high-temperature gas inlet, 12 - product outlet, 13 - carbonate feed inlet, 14 - air distribution plate, 15 - integral catalyst unit, 16 - mechanical oscillation device, 17 - solid powder nozzle, 18 - ventilation hole, 20 - gas-solid product separation device, 21 - feed inlet, 22 - gas outlet, 23 - solid material outlet, 30 - gas-solid heat exchanger, 31 - solid material inlet, 32 - low-temperature gas inlet, 33 - high-temperature gas outlet, 34 - solid product outlet, 40 - solid product recovery unit. Detailed implementation mode

[0049] As Figure 1 shown, the integrated catalyst packing bed process system for fluidized carbonate reduction of the present invention includes a carbonate reactor 10, a gas-solid product separation device 20, a gas-solid heat exchanger 30, and a solid product recovery unit 40, wherein:

[0050] The carbonate reactor 10 is a fluidized bed reactor, preferably a vertical tank body. The bottom of the reactor is a high-temperature gas inlet 11, the top is a product outlet 12, a carbonate feed inlet 13 is provided on the side wall of the lower part of the reactor, a distributor plate 14 is provided below the carbonate feed inlet 13 inside the reactor, and one or more integrated catalyst units 15 are provided above the distributor plate 14; Preferably, a mechanical oscillation device 16 is provided on the outer wall of the reactor corresponding to the position of the integrated catalyst unit 15 for removing solid materials retained in the integrated catalyst unit 15 through mechanical vibration to prevent blockage;

[0051] The gas-solid product separation device 20 is preferably a cyclone separation device. The side wall of the upper part of the device is provided with a feed inlet 21, the top is a gas outlet 22, and the bottom of the device is a solid material outlet 23. The feed inlet 21 is connected to the product outlet 12 of the carbonate reactor 10 through a pipeline;

[0052] The top of the gas-solid heat exchanger 30 is a solid material inlet 31, the bottom is a low-temperature gas inlet 32, the side wall of the upper part is provided with a high-temperature gas outlet 33, and the side wall of the lower part is provided with a solid product outlet 34. The solid material inlet 31 is connected to the solid material outlet 23 of the gas-solid product separation device 20 through a pipeline, and the gas outlet 33 is connected to the gas inlet 11 of the carbonate reactor 10 through a pipeline; Preferably, the solid material inlet 31 and the solid product outlet 34 are connected to the shell side of the gas-solid heat exchanger 30, and the low-temperature gas inlet 32 and the high-temperature gas outlet are connected to the tube side of the gas-solid heat exchanger 30;

[0053] The solid product recovery unit 40 is a receiving bin, which is connected to the solid product outlet 34 of the gas-solid heat exchanger 30 through a pipeline for receiving the solid product obtained by the reaction.

[0054] Furthermore, fixing members (not shown in the figure), such as welding a plurality of limiting blocks on the same horizontal plane, are provided on the inner wall of the carbonate reactor 10 corresponding to the position of the integrated catalyst unit 15 for limiting and fixing the integrated catalyst unit 15. Figure 1The number of the monolithic catalyst units 15 described is three levels. It is easy to understand that the number of levels of the monolithic catalyst units 15 can be adjusted according to actual needs and is not limited to a specific number. Correspondingly, the carbonate reactor 10 can also use different sizes according to the size and number of levels of the monolithic catalyst units 15.

[0055] Preferably, the intervals between the monolithic catalyst units at each level are the same or different. More preferably, the intervals between the monolithic catalyst units at each level are 5 - 20 cm. Further preferably, the intervals between the monolithic catalyst units at each level are 10 cm.

[0056] Preferably, the monolithic catalyst unit includes one or more layers of monolithic catalysts; preferably, the monolithic catalyst unit includes multiple layers of monolithic catalysts. More preferably, there is a heat exchange space between each layer of monolithic catalysts. The composition of the monolithic catalyst can be adjusted according to different reactions or reaction types; the number of layers of the monolithic catalysts at each level can be adjusted according to the reaction conversion efficiency.

[0057] Furthermore, the number of the carbonate feed ports 13 provided on the lower side wall of the reactor can be one or more. For the case of multiple carbonate feed ports 13, the multiple carbonate feed ports 13 are evenly distributed along the outer wall of the reactor. Preferably, as Figure 2 shown, each of the carbonate feed ports 13 includes a solid powder nozzle 17 for transporting the solid carbonate raw material.

[0058] As Figure 3 shown, the air distribution plate 14 is a circular plate provided with a number of air holes 18 and can also be arranged on the inner wall of the reactor by means of the fixing parts on the inner wall of the reactor.

[0059] The monolithic catalyst unit 15 includes a monolithic catalyst, and the monolithic catalyst is preferably a wire mesh catalyst, a plate catalyst, or a honeycomb catalyst.

[0060] The preparation method of the wire mesh catalyst is to load the catalytic metal or metal oxide components on the wire mesh by electrophoretic deposition and impregnation method, and stack the wire mesh into a stainless steel frame to form the wire mesh catalyst; wherein, the mesh number of the wire mesh is 30 - 150 meshes and the thickness is 0.5 - 1 mm.

[0061] The preparation method of the plate catalyst is to load the catalytic metal or metal oxide components on the stainless steel plate by coating method to form the plate catalyst; wherein, the thickness of the steel plate is 1 - 2 mm, the steel plate is placed vertically in the stainless steel frame, and the included angle between two adjacent steel plates is 15 - 45°, and by adjusting this included angle, the gap between two adjacent steel plates can be adjusted accordingly.

[0062] The preparation method of the honeycomb coal type catalyst is to load catalytic metal or metal oxide components on a honeycomb coal shaped carrier by an impregnation method, and place it in a stainless steel frame to form the honeycomb coal type catalyst; wherein, the honeycomb coal shaped carrier is made of porous cordierite material, the opening mesh number is controlled at 30 - 150 meshes, the wall thickness is 1 - 2 mm, and the opening rate is controlled at 60 - 80%.

[0063] The exemplary process flow of fluidized carbonate reduction using the monolithic catalyst packing bed process system in the present invention for fluidized carbonate reduction and producing metal oxides and methanol or syngas is as follows:

[0064] The prepared monolithic catalyst is fixed in the carbonate reactor 10 in stages, the temperature in the carbonate reactor 10 is raised to the reaction temperature, and the pressure in the carbonate reactor 10 is adjusted to the reaction pressure. The carbonate raw material is continuously input into the bottom of the carbonate reactor 10 through the carbonate feed port 13, and the hydrogen supply gas is input into the carbonate reactor 10 through the high-temperature gas inlet 11 controlled by a flow meter. By arranging a wind distribution plate 14 at the lower head of the carbonate reactor 10, the air flow of the hydrogen supply gas is made more uniform. After the hydrogen supply gas enters the carbonate reactor 10, it drives the carbonate particles to move upward together. When passing through the monolithic catalyst area, the hydrogen supply gas drives the carbonate particles to pass through the gaps in the monolithic catalyst. By adjusting the pore size and gas velocity, it is ensured that the carbonate particles are in full contact with the catalyst and the reaction proceeds fully; in addition, by designing a mechanical oscillation device 16 on the side of the monolithic catalyst to disturb the monolithic catalyst unit 15, it is ensured that the monolithic catalyst unit 15 maintains oscillation, so that the fine carbonate particles can smoothly pass through the monolithic catalyst unit 15 to avoid particle blockage; by arranging multiple stages of monolithic catalyst units 15, it is ensured that the raw materials react more fully. The reaction products are output through the product outlet 12 at the top of the carbonate reactor 10; the metal oxide particles as solid products and methanol or syngas as gas products enter the cyclone separator. The separated gas products are discharged from the top of the cyclone separator and collected. The separated solid products can transfer the carried waste heat to the hydrogen supply gas for preheating through the gas-solid heat exchanger 30. Subsequently, the solid products are discharged from the lower end of the gas-solid heat exchanger 30 and enter the receiving bin for collection, and the preheated hydrogen supply gas is transported into the carbonate reactor 10 through the high-temperature gas inlet 11.

[0065] In the present invention, by using an integrated catalyst packing bed process system for fluidized carbonate reduction, the thermal decomposition reaction of metal carbonate and the hydrogenation reduction reaction of in-situ carbon dioxide can be coupled. When the hydrogen supply gas is CH4, the main reaction occurring in the carbonate reactor 10 is as shown in Equation I: CaCO3 + CH4 = CaO + 2H2 + 2CO (I); when the hydrogen supply gas is H2, the main reaction occurring in the carbonate reactor 10 is as shown in Equation II: CaCO3 + 3H2 = CaO + CH3OH + H2O (II).

[0066] Example 1: Reduction of calcium carbonate promoted by CrNi metal wire mesh catalyst

[0067] The 50-mesh metal wire mesh catalyst impregnated with CrNi-based active components is folded and embedded in a stainless steel frame to obtain an integrated catalyst unit 15, and the integrated catalyst unit 15 is fixed inside the carbonate reactor 10; the integrated catalyst is provided with multiple stages at intervals of 10 cm in height to improve the carbonate decomposition rate.

[0068] First, the internal temperature of the carbonate reactor 10 is raised to the target temperature (700 °C), and the internal pressure is controlled at about 0.1 Mpa. Subsequently, 100-mesh calcium carbonate particles are input into the carbonate reactor 10 through the carbonate feed port 13, and the feeding amount is controlled at 2 g / min, and methane is input into the carbonate reactor 10 through the high-temperature gas inlet 11, and the methane flow rate is controlled at 2 L / min; among them, methane is preheated by the gas-solid heat exchanger 30 in advance. After feeding, in the carbonate reactor 10, the methane gas stream drives the carbonate particles to move upward, and the carbonate reduction decomposition reaction occurs rapidly when passing through the catalyst unit. The integrated catalyst unit 15 is provided with three stages. The decomposed products calcium oxide and product gases H2 and CO (i.e., syngas) are output from the carbonate reactor 10 through the product outlet 12 and enter the cyclone separator for separation. Among them, the conversion rate of calcium carbonate is 96%, and the selectivity of CO is 92%.

[0069] Example 2: Reduction of calcium carbonate promoted by CrNi honeycomb catalyst

[0070] The 50-mesh honeycomb catalyst impregnated with CrNi-based active components is embedded in a stainless steel frame to obtain an integrated catalyst unit 15, and the integrated catalyst unit 15 is fixed inside the carbonate reactor 10; the integrated catalyst is provided with multiple stages at intervals of 10 cm in height to improve the carbonate decomposition rate.

[0071] First, raise the temperature inside the carbonate reactor 10 to the target temperature (700 °C) and control the internal pressure at approximately 0.1 Mpa. Subsequently, add 100-mesh calcium carbonate particles through the carbonate feed inlet 13, with the feeding amount controlled at 2 g / min, and input methane through the high-temperature gas inlet 11, with the methane flow rate controlled at 2 L / min; among them, the methane is preheated through the gas-solid heat exchanger 30. After feeding, inside the carbonate reactor 10, the methane gas flow drives the carbonate particles to move upward. When passing through the catalyst unit, a rapid carbonate reduction decomposition reaction occurs. The monolithic catalyst unit 15 is provided with three stages. The decomposed products calcium oxide, product gas H2, and CO are output from the carbonate reactor 10 through the product outlet 12 and enter the cyclone separator for separation. Among them, the conversion rate of calcium carbonate is 85%, and the selectivity of CO is 88%.

[0072] Example 3: Promotion of calcium carbonate reduction by CrNi plate catalyst

[0073] Vertically embed the plate catalyst impregnated with the CrNi-based active component into the stainless steel frame, with an angle of approximately 20° between each plate catalyst to obtain the monolithic catalyst unit 15, and fix the monolithic catalyst unit 15 inside the carbonate reactor 10; the monolithic catalyst is provided with multiple stages at intervals of 10 cm in height to improve the carbonate decomposition rate.

[0074] First, raise the temperature inside the carbonate reactor 10 to the target temperature (700 °C) and control the internal pressure at approximately 0.1 Mpa. Subsequently, input 100-mesh calcium carbonate particles into the carbonate reactor 10 through the carbonate feed inlet 13, with the feeding amount controlled at 2 g / min, and input methane into the carbonate reactor 10 through the high-temperature gas inlet 11, with the methane flow rate controlled at 2 L / min; among them, the methane is preheated through the gas-solid heat exchanger 30. After feeding, inside the carbonate reactor 10, the methane gas flow drives the carbonate particles to move upward. When passing through the catalyst unit, a rapid carbonate reduction decomposition reaction occurs. The monolithic catalyst unit 15 is provided with three stages. The decomposed products calcium oxide, product gas H2, and CO are output from the carbonate reactor 10 through the product outlet 12 and enter the cyclone separator for separation. The conversion rate of calcium carbonate is 80%, and the selectivity of CO is 85%.

[0075] Example 4: Promotion of magnesium carbonate reduction by FeNi metal mesh catalyst

[0076] Fold and embed the 60-mesh metal mesh catalyst impregnated with the FeNi alloy component into the stainless steel frame to obtain the monolithic catalyst unit 15, and fix the monolithic catalyst unit 15 inside the carbonate reactor 10; the monolithic catalyst is provided with multiple stages at intervals of 10 cm in height to improve the carbonate decomposition rate.

[0077] First, raise the internal temperature of the carbonate reactor 10 to the target temperature (500 °C) and control the internal pressure at about 0.1 Mpa. Subsequently, add 120-mesh magnesium carbonate particles through the carbonate feed port 13, with the feeding amount controlled at 2 g / min, and input methane through the high-temperature gas inlet 11, with the methane flow rate controlled at 2 L / min. Among them, the methane gas flow drives the magnesium carbonate particles to move upward, and a rapid carbonate reduction decomposition reaction occurs when passing through the catalyst unit. The monolithic catalyst unit 15 is provided with three stages. The decomposed products, magnesium oxide, product gas H2, and CO are output from the carbonate reactor 10 through the product outlet 12 and enter the cyclone separator for separation. Among them, the conversion rate of magnesium carbonate is 99%, and the selectivity of CO is 90%.

[0078] Example 5: Cu / ZnO / Al2O3 wire mesh catalyst promotes the reduction of magnesium carbonate

[0079] Fold and embed the 75-mesh wire mesh catalyst impregnated with the Cu / ZnO / Al2O3 active component into the stainless steel frame to obtain the monolithic catalyst unit 15, and fix the monolithic catalyst unit 15 inside the carbonate reactor 10. The monolithic catalyst is provided with multiple stages at intervals of 10 cm in height to improve the carbonate decomposition rate.

[0080] First, raise the inside of the carbonate reactor 10 to the target temperature (500 °C) and control the internal pressure at about 5 Mpa. Subsequently, add 150-mesh magnesium carbonate particles through the carbonate feed port 13, with the feeding amount controlled at 2 g / min, and input hydrogen through the high-temperature gas inlet 11, with the gas flow rate controlled at 2 L / min. Among them, hydrogen is preheated by the gas-solid heat exchanger 30 in advance. After feeding, inside the carbonate reactor 10, the hydrogen gas flow drives the carbonate particles to move upward, and a rapid carbonate reduction decomposition and methanol in-situ synthesis reaction occur when passing through the catalyst unit. The monolithic catalyst unit 15 is provided with three stages. The decomposed products, calcium oxide, and product gas methanol are output from the carbonate reactor 10 through the product outlet 12 and enter the cyclone separator for separation. Among them, the conversion rate of magnesium carbonate is 95%, and the selectivity of methanol is 90%.

[0081] Example 6: In2O3 catalyst promotes the reduction of ferrous carbonate

[0082] Fold and embed the 50-mesh wire mesh catalyst impregnated with the In2O3 active component into the stainless steel frame to obtain the monolithic catalyst unit 15, and fix the monolithic catalyst unit 15 inside the carbonate reactor 10. The monolithic catalyst is provided with multiple stages at intervals of 10 cm in height to improve the carbonate decomposition rate.

[0083] First, raise the temperature inside the carbonate reactor 10 to the target temperature (300 °C) and control the internal pressure at about 4 Mpa. Subsequently, add 100-mesh ferrous carbonate particles through the carbonate feed port 13, control the feeding amount at 2 g / min, and input hydrogen through the high-temperature gas inlet 11, with the gas flow rate controlled at 2 L / min; among them, methane is preheated through the gas-solid heat exchanger 30 in advance. After feeding, inside the carbonate reactor 10, the hydrogen gas flow drives the carbonate particles to move upward, and rapid carbonate reduction decomposition and in-situ methanol synthesis reactions occur when passing through the catalyst unit. The monolithic catalyst unit 15 is provided with three stages. The decomposed products CaO and the product gas methanol are output from the carbonate reactor 10 through the product outlet 12 and enter the cyclone separator for separation. Among them, the conversion rate of ferrous carbonate is 90%, and the selectivity of methanol is 92%.

[0084] Comparative Example 1: Reduction of calcium carbonate without catalyst

[0085] In this comparative example, the monolithic catalyst unit 15 is not added to the carbonate reduction decomposition reactor.

[0086] First, raise the temperature inside the carbonate reactor 10 to the target temperature (700 °C) and regulate the internal pressure to about 0.1 Mpa. Subsequently, add 100-mesh calcium carbonate particles through the carbonate feed port 13, control the feeding amount at 2 g / min, and input methane through the high-temperature gas inlet 11, with the methane flow rate controlled at 2 L / min; among them, methane is preheated through the gas-solid heat exchanger 30 in advance. After feeding, inside the carbonate reactor 10, the methane gas flow drives the calcium carbonate particles to move upward. The monolithic catalyst unit 15 is provided with three stages. The decomposed products CaO and the product gases H2 and CO are output from the carbonate reactor 10 through the product outlet 12 and enter the cyclone separator for separation. Among them, the conversion rate of calcium carbonate is 15%, and the selectivity of CO is 30%.

[0087] Comparative Example 2: Reduction of magnesium carbonate without catalyst

[0088] In this comparative example, the monolithic catalyst unit 15 is not added to the carbonate reduction decomposition reactor.

[0089] First, raise the internal temperature of the carbonate reactor 10 to the target temperature (400 °C), regulate the pressure to 5 Mpa, and then add 100-mesh magnesium carbonate particles through the carbonate feed port 13, with the feeding amount controlled at 2 g / min. Input hydrogen through the high-temperature gas inlet 11, and control the hydrogen flow rate at 2 L / min. Among them, methane is preheated through the gas-solid heat exchanger 30 in advance. After feeding, in the carbonate reactor 10, hydrogen molecules drive the magnesium carbonate particles to move upward, and the monolithic catalyst unit 15 is provided with three stages. The decomposed products MgO and product gas methanol are output from the carbonate reactor 10 through the product outlet 12 and enter the cyclone separator for separation. The conversion rate of magnesium carbonate is 10%, and the selectivity of methanol is 20%.

[0090] Table 1: Parameters and process evaluation indexes of examples and comparative examples

[0091]

[0092]

[0093] In summary, the monolithic catalyst packing bed process system and method for fluidized carbonate reduction provided by the present invention have at least one of the following beneficial effects:

[0094] 1. By adopting the monolithic catalyst, it not only ensures the full contact of the gas-solid-solid three phases and improves the efficiency of the carbonate reduction reaction, but also avoids the separation problem of the subsequent oxide solid product and the catalyst solid, realizing the continuous operation of the system.

[0095] 2. The size of the gaps inside the monolithic catalyst and the gas velocity of the reaction gas can be adjusted, or by setting the monolithic catalyst units 15 with multi-stage distribution, so as to ensure that the carbonate particles stay in the catalytic reaction active area for enough time and realize the relatively complete reaction of the carbonate particles (the conversion rate of carbonate is greater than 80%, and can reach 99% after condition optimization).

[0096] 3. By comparing monolithic catalysts with different structural forms, a wire mesh catalyst with relatively excellent carbonate conversion rate and product selectivity is preferably obtained.

[0097] 4. By adding a bin wall vibrator to the outer wall of the reactor, the blockage of materials inside the catalytic bed layer is avoided, ensuring the smooth operation of the fluidized bed process system.

[0098] 5. By coupling the thermal decomposition reaction of metal carbonate and the hydrogenation reduction reaction of carbon dioxide, and using a monolithic catalyst for catalysis, high-value metal oxides and syngas or methanol products are obtained, and the process reaction temperature is significantly reduced compared with the prior art, which is beneficial to promoting energy conservation and emission reduction.

Claims

1. A monolithic catalyst packed bed process system for fluidized carbonate reduction, characterized in that: The system comprises a carbonate reactor (10), a gas-solid product separation device (20), a gas-solid heat exchanger (30), and a solid product recovery unit (40), wherein: The carbonate reactor (10) is a fluidized bed reactor, the bottom of the reactor is a high-temperature gas inlet (11), the top is a product outlet (12), a carbonate feed inlet (13) is provided on the side wall of the lower part of the reactor, an air distribution plate (14) is provided below the carbonate feed inlet (13) inside the reactor, and a primary or multi-stage integrated catalyst unit (15) is provided above the air distribution plate (14); The gas-solid product separation device (20) is provided with a feed inlet (21) on the side wall of the upper part of the device, a gas outlet (22) at the top, and a solid material outlet (23) at the bottom of the device, and the feed inlet (21) is connected to the product outlet (12) of the carbonate reactor (10) through a pipeline; The top of the gas-solid heat exchanger (30) is a solid material inlet (31), the bottom is a low-temperature gas inlet (32), the upper side wall is provided with a high-temperature gas outlet (33), and the lower side wall is provided with a solid product outlet (34), the solid material inlet (31) is connected to the solid material outlet (23) of the gas-solid product separation device (20) through a pipeline, and the gas outlet (33) is connected to the gas inlet (11) of the carbonate reactor (10) through a pipeline; The solid product recovery unit (40) is a material receiving bin connected to the solid product outlet (34) of the gas-solid heat exchanger (30) via a pipeline.

2. The integrated catalyst packed bed process system for fluidized carbonate reduction according to claim 1, characterized in that: A mechanical oscillation device (16) is provided on the outer wall of the carbonate reactor (10) at a position corresponding to the integral catalyst unit (15).

3. The integrated catalyst packed bed process system for fluidized carbonate reduction according to claim 1, characterized in that: The monolithic catalyst is selected from one or more of a metal mesh catalyst, a plate catalyst or a honeycomb catalyst.

4. The integrated catalyst packed bed process system for fluidized carbonate reduction according to claim 1, characterized in that: The gas-solid product separation device (5) is a cyclone separator; the material receiving bin is connected to the cyclone separator.

5. The integrated catalyst packed bed process system for fluidized carbonate reduction according to claim 1, characterized in that: The solid material inlet (31) and the solid product outlet (34) are connected to the shell side of the gas-solid heat exchanger (30), and the low-temperature gas inlet (32) and the high-temperature gas outlet are connected to the tube side of the gas-solid heat exchanger (30).

6. The integrated catalyst packed bed process system for fluidized carbonate reduction according to claim 1, characterized in that: A plurality of carbonate feed inlets (13) are arranged on the lower side wall of the reactor and are evenly distributed along the outer wall of the reactor.

7. A method for reducing fluidized carbonate, characterized in that: The method comprises the following steps: S1: raising the temperature in the carbonate reactor to the reaction temperature, and adjusting the pressure in the carbonate reactor to the reaction pressure; S2: The carbonate raw material is input into the bottom of the carbonate reactor through the carbonate feed pipe, and the hydrogen supply gas is input into the bottom of the carbonate reactor through the gas feed pipe. After the hydrogen supply gas enters the carbonate reactor, it drives the carbonate particles to move from bottom to top, so that the carbonate contacts the integral catalyst unit and reacts; wherein the particle size of the carbonate input into the carbonate reactor is 30 to 60% of the pores or intervals of the integral catalyst. S3: The reaction product is output through the product discharge pipeline at the top of the carbonate reactor and enters the gas-solid product separation device for separation; S4: Collect the gaseous product output from the gas product discharge pipeline of the gas-solid product separation device; and collect the solid product using the solid product recovery unit.

8. The method according to claim 7, characterized in that The hydrogen supply gas is methane, and the gas product is synthesis gas; the hydrogen supply gas is hydrogen, and the gas product is methanol; or, the hydrogen supply gas is a mixture of methane and hydrogen, and the gas product is a mixture of synthesis gas and methanol.

9. The method according to claim 7, characterized in that The solid product is a metal oxide.

10. The method according to claim 7, characterized in that The carbonate is selected from one or more of calcium carbonate, magnesium carbonate, ferrous carbonate, cobalt carbonate, nickel carbonate, chromium carbonate, cuprous carbonate, zinc carbonate, indium carbonate or aluminum carbonate.

11. The method according to claim 7, characterized in that The reaction temperature is 200-900°C.

12. The method according to claim 7, characterized in that The reaction pressure is 0.05-6Mpa.

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