Tubular reaction device and carbon-containing fuel and water gas conversion, grading and reforming hydrogen production method

Abstract

The invention discloses a tubular reaction device and a carbon-containing fuel and water gas conversion staged reforming hydrogen production method, and the device comprises a heating furnace which is divided into an upper-stage heating furnace and a lower-stage heating furnace; the reactor is of a tubular structure and sequentially comprises a carbon-containing fuel reforming area, a gas mixing section and a water gas conversion area from top to bottom; the temperature control module is respectively connected with the upper-stage heating furnace and the lower-stage heating furnace and is used for independently controlling the temperatures of the two heating furnaces; one end of the needle tube is connected with the micro-injection pump, and the other end of the needle tube is connected into the gas mixing section of the reactor. The reactor is designed to be of a vertical pipe type structure, the reforming area and the transformation area are coated with the independent upper-stage heating furnace and the independent lower-stage heating furnace respectively, the double-temperature-area grading design is achieved, two reaction areas with different temperature requirements are independently and accurately heated and controlled in one reactor, and the temperature of the two reaction areas can be controlled. And the problems of thermodynamic conflict, difficult thermal management and poor reaction synergy are avoided.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of hydrogen production and reaction equipment, in particular to a tubular reaction device and a hydrogen production method through staged reforming of carbon-containing fuel and water gas shift. BACKGROUND

[0002] As the core carrier of the future low-carbon energy system, hydrogen production technology is highly concerned. In the current energy structure, hydrogen production from carbon-containing fuel occupies an important position. The steam methane reforming (SMR) technology is a relatively mature hydrogen production process in the industry. More than 70% of hydrogen in the world is produced by the SMR technology. Although the technology is mature, it has significant defects: high energy consumption, 30% of which is used for heating due to strong endothermic characteristics; high carbon emission intensity, 10-12 tons of CO2 are emitted per ton of hydrogen; strict requirements on raw materials, requiring methane purity of 95% or above, which limits the use of industrial by-product gas; and additional energy consumption of 15% in the subsequent PSA purification link.

[0003] To break through these limitations, the methane simultaneous tri-reforming technology can achieve heat balance in the reaction system by synergistically utilizing CH4, CO2 and H2O, which can significantly reduce energy consumption. However, in practical applications, the reforming reaction and the water gas shift (WGS) reaction or the sorption enhanced water gas shift (SEWGS) reaction face thermodynamic conflicts. The reforming reaction needs to be carried out at a high temperature of 750-850 DEG C to promote the cracking of hydrocarbons and the conversion of CO2. The WGS reaction requires a medium temperature of 300-600 DEG C to improve the selectivity of hydrogen. The temperature requirements of the two reactions are quite different, making it difficult to meet the requirements in the same reaction space, resulting in low hydrogen production efficiency, short service life of the catalyst due to high temperature deactivation or low temperature carbon deposition, and further limiting the application of the technology in small and medium-sized devices, especially when dealing with complex carbon-containing fuels.

[0004] In the prior art, the coupling of the reforming of carbon-containing fuel and the WGS / SEWGS reaction is usually designed in a separate device. After the reforming reaction is completed in a high-temperature reactor, the product is cooled and transported to another reactor for WGS or SEWGS reaction, avoiding the temperature coordination conflict in the tri-reforming. This separation mode not only causes a large amount of heat loss, but also makes the system have low integration degree and large equipment footprint. Especially when the SEWGS technology is introduced, the connection of the independent adsorbent regeneration system and the reforming system increases the process complexity and operating cost. Although the SEWGS technology can break through the thermodynamic limit of the WGS by adsorbing CO2 in situ, it does not form an efficient heat coupling with the reforming reaction, and the required steam usually depends on an external heating source, which not only increases the energy consumption, but also may cause fluctuations in reaction efficiency due to condensation in the steam transportation process.

[0005] Therefore, the application provides a device and method for hydrogen production by staged reforming of carbon-containing fuel and water gas shift or adsorption-enhanced water gas shift, which improves the conversion efficiency of carbon-containing fuel and the purity of hydrogen product through precise temperature control and efficient heat coupling, and simplifies the process to promote industrial application. SUMMARY

[0006] The application aims to provide a tubular reactor and a method for hydrogen production by staged reforming of carbon-containing fuel and water gas shift, so as to solve the problems of difficult heat management of the same-stage triple reforming technology, high energy consumption of the separated system, and poor coordination between the water gas shift or adsorption-enhanced water gas shift and the reforming reaction in the hydrogen production technology of carbon-containing fuel.

[0007] To achieve the above-mentioned purpose, the application provides the following technical scheme: a tubular reactor for hydrogen production by staged reforming of carbon-containing fuel and water gas shift or adsorption-enhanced water gas shift, comprising: a heating furnace, which is divided into an upper heating furnace and a lower heating furnace; a reactor, which is a tubular structure and sequentially comprises a carbon-containing fuel reforming zone, a gas mixing section, and a water gas shift zone from top to bottom; wherein the carbon-containing fuel reforming zone is heated by the upper heating furnace, and the water gas shift zone is heated by the lower heating furnace; a temperature control module, which is connected with the upper heating furnace and the lower heating furnace respectively and is used for independently controlling the temperature of the two heating furnaces; a micro-injection pump and a needle tube, one end of the needle tube being connected with the micro-injection pump, and the other end of the needle tube being connected with the gas mixing section of the reactor.

[0008] As a preferred scheme of the application, the upper and lower ends of the reactor are respectively provided with an upper cover and a lower cover. The upper cover is provided with a mixed feeding port for feeding of solid and gas feeding ports. The lower cover is provided with a gas outlet.

[0009] As a preferred scheme of the application, the middle part of the reactor is inwardly tapered to form a gas mixing section, and the two ends of the tapered part are respectively formed with an upper boss and a lower boss. The carbon-containing fuel reforming zone is provided with a movable baffle at the upper boss. The water gas shift zone is provided with a fixed baffle inside.

[0010] As a preferred scheme of the application, the gas mixing section of the reactor is provided with a water vapor feeding port on the side wall, and the needle tube is connected with the water vapor feeding port.

[0011] As a preferred scheme of the present application, wherein: the micro-injection pump injects water into the water vapor feeding port through a needle tube, and the water is converted into water vapor by heating the carbon-containing fuel reforming region with the upper heating furnace.

[0012] As a preferred scheme of the present application, wherein: the micro-injection pump is also used to accurately control the flow rate and flow velocity of the injected water vapor.

[0013] As a preferred scheme of the present application, wherein: the movable baffle is used to place a catalyst for the carbon-containing fuel reforming reaction, and the upper heating furnace controls the temperature of the carbon-containing fuel reforming region at 750-850℃.

[0014] As a preferred scheme of the present application, wherein: the fixed baffle is used to place a catalyst for the water gas shift reaction or a bifunctional material for adsorbing and enhancing the water gas shift reaction, and the lower heating furnace controls the temperature of the water gas shift region at 300-600℃.

[0015] A method for hydrogen production by staged reforming of carbon-containing fuel and water gas shift, comprising the following steps: S1, placing a catalyst for the carbon-containing fuel reforming reaction on the movable baffle, and placing a catalyst for the water gas shift reaction or a bifunctional material for adsorbing and enhancing the water gas shift reaction on the fixed baffle; S2, introducing a carrier gas from the gas feeding port, turning on the heating furnace, and setting the temperature of the upper heating furnace at 750-850℃ and the temperature of the lower heating furnace at 300-600℃ by the temperature control module for preheating; S3, after the preheating reaches the set temperature, mixing the carbon-containing fuel with CO2 to obtain a raw gas, introducing the raw gas into the carbon-containing fuel reforming region of the heating furnace from the gas feeding port for reaction to generate a reforming product, and injecting water into the gas mixing section by the micro-injection pump and the needle tube to evaporate into water vapor by the reaction temperature of the carbon-containing fuel reforming region, and then entering the water gas shift region for reaction after fully mixing with the reforming product; S4, discharging the synthesis gas after reaction from the gas outlet of the reactor and collecting it for subsequent analysis; S5, after the reaction is completed, stopping the feeding and heating, stopping the gas collection, and ending the operation of the device.

[0016] As a preferred scheme of the present application, when the carbon-containing fuel is methane, the molar ratio of the introduced CO2 to CH4 is 1:1.

[0017] Compared with the prior art, the present application has the following beneficial effects: 1. This invention achieves a dual-temperature zone design by designing the reactor as a vertical tube structure and using independent upper and lower stage heaters to cover the reforming zone and the conversion zone respectively. This allows for independent and precise heating and control of two reaction zones with different temperature requirements within a single reactor, avoiding problems such as thermodynamic conflicts, difficult thermal management, and poor reaction synergy. 2. This invention utilizes the high temperature of the reforming zone to instantly vaporize the water injected into the mixing section, eliminating the need for a separate steam generator, reducing system energy consumption, and allowing the high-temperature products of the reforming reaction to directly enter the medium-temperature conversion zone, thus effectively utilizing their sensible heat. 3. By replacing the catalyst or bifunctional material on the movable baffle and the fixed baffle, the same device can be flexibly used in the traditional water-gas conversion process or the adsorption-enhanced water-gas conversion process, adapting to the needs of hydrogen products with different purities. Moreover, the device is suitable for the efficient hydrogen production of various carbon-containing fuels such as natural gas, biomass gas, and coke oven gas. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the reactor structure of the present invention; Figure 3 These are top views and cross-sectional views of the reactor of the present invention; Figure 4 This is a comparative experimental evaluation diagram of hydrogen production by methane dry reforming-water-gas shift staged reforming and hydrogen production by the same stage triple reforming in Embodiment 1 of the present invention. Figure 5 This is an experimental evaluation diagram of obtaining high-purity H2 from methane dry reforming-adsorption enhanced water-gas shift staged reforming in Embodiment 2 of the present invention.

[0019] In the diagram: 1. Heating furnace; 101. Upper heating furnace; 102. Lower heating furnace; 2. Reactor; 201. Carbon fuel reforming zone; 202. Gas mixing section; 203. Water-gas conversion zone; 3. Temperature control module; 4. Micro-injection pump; 5. Needle; 6. Upper boss; 7. Lower boss; 8. Solid feed inlet; 9. Gas feed inlet; 10. Steam feed inlet; 11. Upper cover; 12. Lower cover; 13. Gas outlet; 14. Movable baffle; 15. Fixed baffle. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please seeFigures 1-3 A tubular reactor for hydrogen production via staged reforming of carbon-containing fuels and water-gas shift (WGS) or adsorption-enhanced water-gas shift (SEWGS) methods, comprising: Heating furnace 1 is divided into upper heating furnace 101 and lower heating furnace 102; Reactor 2 is a tubular structure made of 304 stainless steel, and from top to bottom it includes a carbon fuel reforming zone 201, a gas mixing section 202 and a water-gas conversion zone 203. Among them, the carbon-containing fuel reforming zone 201 is covered and heated by the upper-level heater 101; the water-gas conversion zone 203 is covered and heated by the lower-level heater 102; Temperature control module 3 is connected to the upper heating furnace 101 and the lower heating furnace 102 respectively, and is used to independently control the temperature of the two heating furnaces; The micro-injection pump 4 and the needle 5 are specifically designed as an extended stainless steel needle. One end of the needle 5 is connected to the micro-injection pump 4, and the other end of the needle 5 is connected to the gas mixing section 202 of the reactor 2.

[0022] The reactor 2 of this device is provided with an upper cover 11 and a lower cover 12 at its upper and lower ends, respectively; The upper cover 11 is provided with a mixed feed inlet through a solid feed inlet 8 and a gas feed inlet 9; the lower cover 12 is provided with a gas outlet 13.

[0023] The middle part of the reactor 2 converges inward to form a gas mixing section 202, and the two ends of the converged part form an upper protrusion 6 and a lower protrusion 7 respectively; the carbon fuel reforming zone 201 is provided with a movable baffle 14 at the upper protrusion 6; the water-gas conversion zone 203 is provided with a fixed baffle 15.

[0024] The movable baffle 14 is used to place the catalyst for the carbon fuel reforming reaction. The upper heating furnace 101 controls the temperature of the carbon fuel reforming zone 201 at 750-850℃. Taking the methane dry reforming reaction as an example, the carbon fuel reforming reaction is suitable for using Ni-based catalysts, such as Ni / CeO2-Al2O3. The fixed baffle 15 is used to place catalysts for the water-gas shift reaction or bifunctional materials that adsorb and enhance the water-gas shift reaction. The lower-stage heater 102 controls the temperature of the water-gas shift zone 203 at 300-600℃. Among them, Fe-based catalysts, such as NiCu / Fe2O3, are used for the WGS reaction, and Ca-based bifunctional materials, such as Fe-CaO / CaO-Ca, are used for the SEWGS reaction. 12 Al 14 O 33 .

[0025] This invention also provides a method for hydrogen production through staged reforming of carbon-containing fuel and water-gas, applied to the above-mentioned tubular reactor device, comprising the following steps: S1. Place the catalyst for the reforming reaction of carbon-containing fuel on the movable baffle 14, and place the catalyst for the water-gas shift reaction or the bifunctional material for adsorption-enhancing water-gas shift reaction on the fixed baffle 15. S2. Carrier gas is introduced through gas inlet 9, the heating furnace is turned on, and the temperature of the upper heating furnace 101 is set to 750-850℃ and the temperature of the lower heating furnace 102 is set to 300-600℃ through temperature control module 3 for preheating. S3. After preheating to the set temperature, carbon fuel and CO2 are mixed to obtain raw material gas, which is introduced into the carbon fuel reforming zone 201 of the heating furnace 1 through the gas inlet 9 to react and generate reforming products. At the same time, water is injected into the mixing section 202 through the micro injection pump 4 and the syringe 5. Water evaporates into water vapor by the reaction temperature of the carbon fuel reforming zone 201. After being fully mixed with the reforming products, it enters the water-gas conversion zone 203 for reaction. When the carbon fuel is methane, the molar ratio of CO2 to CH4 introduced is 1:1. S4. The syngas after the reaction is discharged from the outlet 13 of reactor 2 and collected for subsequent analysis. S5. After the reaction is complete, stop feeding and heating, stop collecting gas, and the operation of the device will end.

[0026] Example 1

[0027] Based on the above apparatus and method, a comparative experiment was conducted on hydrogen production by staged reforming of methane dry reforming-water gas shift and hydrogen production by the same stage triple reforming.

[0028] Methane dry reforming-water-gas shift staged reforming for hydrogen production: Step 1: Place 100mg of catalyst on the movable baffle 14 and fix it in the upper boss 6. Spread 5g of quartz sand on the fixed baffle 15 and weigh 0.4g of catalyst and place it on top of the quartz sand.

[0029] Step 2: Introduce N2 at a flow rate of 80 mL / min through gas inlet 9, turn on the heating furnace, and set the temperature of the upper heating furnace 101 to 800℃ and the temperature of the lower heating furnace 102 to 800℃ respectively according to the characteristics of reforming and WGS, for preheating. Step 3: After reaching the set temperature, CH4 and CO2 are introduced into the gas inlet 9 at a flow rate of 10 mL / min. Water is injected into the steam inlet 10 through the syringe 5 by the micro-injection pump 4. The water evaporates into steam based on the reaction temperature of the carbon fuel reforming zone 201. The steam flow rate is adjusted according to the S / C ratio of 2.5. After CH4 and CO2 react in the carbon fuel reforming zone 201, the reforming products CO, H2, and steam are uniformly mixed in the mixing section 202 and then enter the water-gas conversion zone 203 for full reaction. Step 4: The syngas after the reaction is discharged from the outlet 13 of reactor 2 and collected for subsequent analysis; Step 5: After the reaction is complete, stop feeding and heating, stop collecting gas, and the operation of the device will end.

[0030] Same-stage triple reforming for hydrogen production: Step 1: Place 100mg of catalyst on the movable baffle 14 and fix it inside the upper boss 6; Step 2: Introduce N2 at a flow rate of 80 mL / min through gas inlet 9, turn on the heater, and set the temperature of the upper heater 101 connected to the carbon fuel reforming zone 201 to 800℃ for preheating. Step 3: After reaching the set temperature, CH4, CO2 and water vapor with a flow rate of 10 mL / min are introduced through the gas inlet 9, and the reaction is fully carried out in the water-gas conversion zone 203. Step 4: The syngas after the reaction is discharged from the outlet 13 of reactor 2 and collected for subsequent analysis; Step 5: After the reaction is complete, stop feeding and heating, stop collecting gas, and the operation of the device will end.

[0031] Example 2

[0032] Based on the above apparatus and method, hydrogen production is achieved through staged reforming of methane dry reforming-adsorption-enhanced water-gas shift reforming: Step 1: Place 100mg of catalyst on the movable baffle 14 and fix it in the upper boss 6. Spread 5g of quartz sand on the fixed baffle 15 and weigh 1000mg of bifunctional material and place it on top of the quartz sand. Step 2: Introduce N2 at a flow rate of 80 mL / min through gas inlet 9, turn on the heating furnace, and set the temperature of the upper heating furnace 101 to 800℃ and the temperature of the lower heating furnace 102 to 600℃ according to the characteristics of reforming and SEWGS, respectively, for preheating. Step 3: After reaching the set temperature, CH4 and CO2 are introduced into the gas inlet 9 at a flow rate of 10 mL / min. Water is injected into the steam inlet 10 through the syringe 5 by the micro-injection pump 4. The water evaporates into steam based on the reaction temperature of the carbon fuel reforming zone 201. The flow rate of the steam is adjusted according to the S / C ratio of 5. After CH4 and CO2 react in the carbon fuel reforming zone 201, the reforming products CO and H2 are uniformly mixed with the steam in the mixing section 202 and then enter the water-gas conversion zone 203 for full reaction. Step 4: The syngas after the reaction is discharged from the outlet 13 of reactor 2 and collected for subsequent analysis; Step 5: After the reaction is complete, stop feeding and heating, stop collecting gas, and the operation of the device will end.

[0033] In summary, comparing the three systems and methods used for hydrogen production, we can obtain... Figure 4 , Figure 5 Experimental data, among which, Figure 4 The left Y-axis represents H2 production, the first right Y-axis represents the percentage of gas composition, and the second right Y-axis represents the CH4 conversion rate. Figure 5 The left Y-axis represents the percentage of gas composition; Figure 4 The results clearly show that the hydrogen yield in staged reforming is significantly superior to that of the traditional synergistic steam reforming and dry reforming (CSDRM) system: the hydrogen yield of the CSDRM system is approximately 42%, while that of staged reforming increases to approximately 50%, an increase of nearly 8%; in terms of gas composition, the H2 content in staged reforming also increases from approximately 59% in CSDRM to nearly 63.8%, while the CO content decreases significantly from approximately 10% in CSDRM to approximately 6% in staged reforming; at the same time, the percentage of CO2 increases from approximately 18% in CSDRM to approximately 27% in staged reforming; and the methane conversion rate also increases by 7%; Figure 5 Experimental data show that when performing methane dry reforming-adsorption enhanced water-gas shift staged reforming for hydrogen production, the H2 purity is as high as 92% or more, and the total of other components is less than 10%, providing an experimental data basis for subsequent industrial applications.

[0034] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A tubular reactor for hydrogen production via carbon-containing fuel reforming and water-gas shift or adsorption-enhanced water-gas shift staged reforming, characterized in that: include: The heating furnace (1) is divided into an upper heating furnace (101) and a lower heating furnace (102). The reactor (2) is a tubular structure, which includes a carbon fuel reforming zone (201), a gas mixing section (202), and a water-gas conversion zone (203) from top to bottom. The carbon-containing fuel reforming zone (201) is covered and heated by the upper-level heater (101); the water-gas conversion zone (203) is covered and heated by the lower-level heater (102). The temperature control module (3) is connected to the upper heating furnace (101) and the lower heating furnace (102) respectively, and is used to independently control the temperature of the two heating furnaces; A micro-injection pump (4) and a syringe (5), one end of which is connected to the micro-injection pump (4) and the other end of which is connected to the mixing section (202) of the reactor (2).

2. The tubular reaction apparatus according to claim 1, characterized in that: The reactor (2) is provided with an upper cover (11) and a lower cover (12) at its upper and lower ends, respectively. The upper cover (11) is provided with a mixed feed inlet through which solid feed inlet (8) and gas feed inlet (9) feed; The lower cover (12) is provided with an air outlet (13).

3. The tubular reaction apparatus according to claim 2, characterized in that: The reactor (2) is converging inward to form a gas mixing section (202), and an upper boss (6) and a lower boss (7) are formed at both ends of the converging part. The carbon-containing fuel reforming zone (201) is provided with a movable baffle (14) at the upper boss (6). The water-gas conversion zone (203) is equipped with a fixed baffle (15).

4. The tubular reaction apparatus according to claim 1, characterized in that: A steam inlet (10) is provided on the side wall of the mixing section (202) of the reactor (2), and the needle (5) is connected to the steam inlet (10).

5. The tubular reaction apparatus according to claim 4, characterized in that: The micro-injection pump (4) injects water into the steam inlet (10) through the needle (5) and uses the upper heating furnace (101) to heat the carbon-containing fuel reforming zone (201) to convert the water into steam.

6. The tubular reaction device according to claim 5, wherein the micro-injection pump (4) is also used to precisely control the flow rate and velocity of the injected water vapor.

7. The tubular reaction apparatus according to claim 3, characterized in that: The movable baffle (14) is used to place the catalyst for the carbon fuel reforming reaction, and the upper heating furnace (101) controls the temperature of the carbon fuel reforming zone (201) at 750-850°C.

8. The tubular reaction apparatus according to claim 3, characterized in that: The fixed baffle (15) is used to place the catalyst for the water-gas conversion reaction or the bifunctional material that adsorbs and enhances the water-gas conversion reaction. The lower heating furnace (102) controls the temperature of the water-gas conversion zone (203) at 300-600°C.

9. A method for producing hydrogen through staged reforming of carbon-containing fuel and water gas, applied to the tubular reactor apparatus according to any one of claims 1 to 8, characterized in that: Includes the following steps: S1. Place the catalyst for the reforming reaction of carbon fuel on the movable baffle (14) and place the catalyst for the water-gas shift reaction or the bifunctional material for adsorption-enhanced water-gas shift reaction on the fixed baffle (15). S2. Carrier gas is introduced through the gas inlet (9), the heating furnace is turned on, and the temperature of the upper heating furnace (101) is set to 750-850℃ and the temperature of the lower heating furnace (102) is set to 300-600℃ through the temperature control module (3) for preheating. S3. After preheating to the set temperature, carbon fuel and CO2 are mixed to obtain raw material gas, which is then introduced into the carbon fuel reforming zone (201) of the heating furnace (1) through the gas inlet (9) to react and generate reforming products. At the same time, water is injected into the mixing section (202) through the micro-injection pump (4) and the syringe (5). Water evaporates into water vapor by relying on the reaction temperature of the carbon fuel reforming zone (201). After being fully mixed with the reforming products, it enters the water-gas conversion zone (203) for reaction. S4. The syngas after the reaction is discharged from the outlet (13) of the reactor (2) and collected for subsequent analysis; S5. After the reaction is complete, stop feeding and heating, stop collecting gas, and the operation of the device will end.

10. The method for producing hydrogen through staged reforming of carbon-containing fuels and water-gas according to claim 9, characterized in that: When the carbon-containing fuel is methane, the molar ratio of CO2 to CH4 introduced is 1:1.

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