Methanol cracking hydrogen production process and system

Abstract

The invention relates to the technical field of methanol cracking hydrogen production, in particular to a process and a system for methanol cracking hydrogen production. Raw material methanol liquid is conveyed to a heat exchanger from a methanol storage tank through a metering pump and is heated and preheated through heat exchange of the heat exchanger, and the preheated raw material methanol liquid is conveyed into a methanol vaporizer to be vaporized into methanol steam; methanol steam enters a reactor and is catalyzed by a catalyst, a cracking reaction is carried out, high-temperature converted gas of hydrogen and carbon monoxide is generated, the high-temperature converted gas is conveyed to a product end after being subjected to heat exchange and cooling by a heat exchanger, the high-temperature converted gas is used as a heat source to exchange heat with fed methanol, and the converted gas is cooled while the methanol is preheated, so that energy complementation is realized; and the process ensures that methanol is fully vaporized, the temperature of the reactor is controlled at the optimal temperature for direct methanol cracking, and the direct methanol cracking reaction is sufficient and less in side reaction under the catalysis of a copper-based catalyst with high activity and good selectivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of methanol cracking hydrogen production, and particularly relates to a methanol cracking hydrogen production process and system. BACKGROUND

[0002] Hydrogen is regarded as an ideal clean energy due to its high efficiency, cleanness and high energy density. As one of important means for hydrogen production, methanol hydrogen production technology has advantages of wide raw material source, low price, convenient storage and transportation and high conversion efficiency, and is an important development direction of hydrogen production technology. At present, methanol steam reforming is a main method for methanol hydrogen production, and the specific reaction is as shown below:

[0003]

[0004] However, the current methanol hydrogen production method mainly has the following problems: (1) the methanol decomposition efficiency is not high, and the process is slow to heat up, so that the methanol decomposition is often incomplete, resulting in large methanol consumption or low hydrogen production, and high carbon dioxide content in the product; (2) the process is manually controlled, and the operator needs to monitor the process state in real time, so that the operator has high professional requirements and high work intensity. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a methanol cracking hydrogen production process and system to solve the problem of low methanol decomposition efficiency in the existing methanol cracking hydrogen production.

[0006] In order to achieve the above purpose, the present application provides a methanol cracking hydrogen production process, which comprises the following steps:

[0007] Methanol feeding: the raw material methanol liquid is transported from a methanol storage tank to a heat exchanger by a methanol metering pump;

[0008] Methanol preheating: the raw material methanol liquid is heated to 60-80℃ by the heat exchanger;

[0009] Methanol vaporization: the preheated raw material methanol liquid is sent into a methanol vaporizer to be vaporized into methanol steam with a temperature of 180-200℃;

[0010] Methanol direct cracking: the methanol steam is sent into a reactor to be catalyzed by a catalyst to occur cracking reaction under the condition of a temperature of 230-250℃, and high-temperature conversion gas of hydrogen and carbon monoxide is generated;

[0011] Methanol cooling: the high-temperature conversion gas is cooled by the heat exchanger and then is transported to a product end.

[0012] Preferably, the methanol vaporizer and the reactor adopt electrically heated conductive oil to provide heat source.

[0013] Preferably, the catalyst is a copper-based catalyst.

[0014] Preferably, the hydrogen content in the high-temperature conversion gas obtained by direct cracking of methanol is 60%-64%, and the carbon monoxide content is 30%-34%.

[0015] The application also provides a methanol cracking hydrogen production system, comprising a methanol storage tank, a methanol metering pump, a heat exchanger, a methanol vaporizer and a reactor connected in sequence, and an outlet pipeline connected to the tail end of the reactor, one end of the outlet pipeline being connected to the heat exchanger for heat exchange with the raw methanol liquid.

[0016] Preferably, a controller is further included, a liquid level transmitter is arranged on the methanol storage tank for measuring the remaining amount of the methanol storage tank and transmitting the measurement data to the controller, and when the remaining amount of the methanol storage tank is lower than a minimum set value, the controller sends an insufficient amount alarm signal.

[0017] Preferably, a pipeline flow meter is arranged on the connecting pipeline between the methanol metering pump and the heat exchanger, a first temperature transmitter and a first pressure transmitter are arranged on the methanol vaporizer, a second temperature transmitter and a second pressure transmitter are arranged on the reactor, the first temperature transmitter, the first pressure transmitter, the second temperature transmitter and the second pressure transmitter are connected to the input end of the controller through signal lines, the power driving elements of the controlled modules are controlled by the controller, and the process conditions of the methanol direct cracking hydrogen production are controlled.

[0018] Preferably, the power driving elements of the controlled modules include a pump rotor driving element of the methanol metering pump, electric heating wires of the methanol vaporizer, electric heating wires of the reactor, and a back pressure valve core arranged on the outlet pipeline.

[0019] Preferably, a rotating drum is arranged at a central position in the connecting pipeline between the methanol vaporizer and the reactor, a rotating shaft is rotatably connected to one end of the rotating drum, one end of the rotating shaft penetrates out of the rotating drum and is connected to a rotating blade, a plurality of air inlet holes are arranged on the rotating blade, the rotating shaft is designed in a hollow structure and is connected to the air inlet holes, an elastic member is connected to the other end of the rotating drum, one end of the elastic member is connected to an abutting plate, an air outlet pipe is connected to the other end of the rotating drum, one end of the air outlet pipe penetrates out of the connecting pipeline and is connected to an on-off valve, when the on-off valve is in an initial closed state, the elastic member pushes the abutting plate to make the abutting plate abut against the rotating shaft, when the on-off valve is opened and air is sucked out through the air outlet pipe, the abutting plate moves horizontally away from the rotating shaft, the rotating blade rotates perpendicularly to the air outlet direction in the connecting pipeline, and air is discharged outwards through the air inlet holes, the rotating shaft and the air outlet pipe, for detecting the methanol concentration in the discharged air.

[0020] The beneficial effects of the present application are as follows: the raw material methanol liquid is transported from a methanol storage tank to a heat exchanger by a metering pump, the raw material methanol liquid is preheated by heat exchange in the heat exchanger, the preheated raw material methanol liquid is sent into a methanol vaporizer, and the raw material methanol liquid is vaporized into methanol steam, the methanol steam enters a reactor and is catalyzed by a catalyst to generate high-temperature conversion gas of hydrogen and carbon monoxide, the high-temperature conversion gas is transported to a product end after heat exchange and cooling in the heat exchanger, the high-temperature conversion gas is used as a heat source to exchange heat with the feed methanol, the methanol is preheated at the same time as the conversion gas is cooled, energy complementation is realized, the overall energy consumption of the process is reduced, costs are saved, the process ensures that the methanol is fully vaporized, the temperature of the reactor is controlled at the best temperature for direct methanol cracking, the direct methanol cracking reaction is sufficient, the selectivity of the copper-based catalyst is good, the byproduct reaction is less, the content of the product hydrogen and carbon monoxide is high, and the product can be directly used as fuel, the control system is matched with the methanol hydrogen production reaction process, the process conditions can be monitored and adjusted in real time, and the safety, stability, reliability and convenience of the methanol direct cracking hydrogen production process are significantly improved, and a large amount of manpower and resources is saved. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only illustrate the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0022] Figure 1 It is a schematic diagram of the overall structure of the present application.

[0023] Figure 2 It is a schematic diagram of the structure of the present application when the switch valve is in the initial closed state.

[0024] Figure 3 It is a schematic diagram of the present application. Figure 2 It is an enlarged schematic diagram of position A in the present application.

[0025] Figure 4 It is a schematic diagram of the structure of the present application when the switch valve is opened.

[0026] Figure 5 It is a schematic diagram of the present application. Figure 4 It is an enlarged schematic diagram of position B in the present application.

[0027] In the figure, the following are marked:

[0028] 1, methanol storage tank; 2, methanol metering pump; 3, heat exchanger; 4, methanol vaporizer; 5, reactor; 6, liquid level transmitter; 7, pipeline flow meter; 8, first temperature transmitter; 9, first pressure transmitter; 10, second temperature transmitter; 11, second pressure transmitter; 12, controller; 13, display terminal; 14, back pressure valve; 15, rotating drum; 16, rotating shaft; 17, rotating blade; 18, elastic member; 19, stop plate; 20, gas outlet pipe; 21, on-off valve. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with specific examples.

[0030] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present application should be understood as the common meanings understood by those skilled in the art to which the present application belongs. The terms "first", "second" and similar terms used in the present application do not represent any order, number or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar terms mean that the elements or objects before the terms cover the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "up", "down", "left", "right" and the like are only used to represent relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships may also change accordingly.

[0031] As shown in Figure 1 A methanol cracking hydrogen production process, including the following steps, methanol feed: raw methanol liquid is transported from the methanol storage tank 1 to the heat exchanger 3 by the methanol metering pump 2; methanol preheating: the raw methanol liquid of the feed is heated to 60-80℃ by the heat exchanger 3; methanol vaporization: the preheated raw methanol liquid is sent into the methanol vaporizer 4 and vaporized into methanol steam with a temperature of 180-200℃; methanol direct cracking: the methanol steam enters the reactor 5 and is catalyzed by the catalyst, and the cracking reaction occurs at a temperature of 230-250℃ to generate high-temperature conversion gas of hydrogen and carbon monoxide; methanol cooling: the high-temperature conversion gas is cooled by the heat exchanger 3 and then transported to the product end.

[0032] Example 1:

[0033] As shown in Figure 1As shown in the figure, a kind of methanol cracking hydrogen production process, its technical scheme is basically same with embodiment 1, difference is as follows: the raw material methanol liquid after preheating is vaporized into 200 ℃ methanol steam in methanol vaporizer 4;Cracking reaction occurs under the reaction condition of temperature 230 ℃, pressure 0.3 MPa, and hydrogen and carbon monoxide high temperature conversion gas are generated.

[0034] Embodiment 2:

[0035] As shown in the figure, a kind of methanol cracking hydrogen production process, its technical scheme is basically same with embodiment 1, difference is as follows: the raw material methanol liquid after preheating is vaporized into 200 ℃ methanol steam in methanol vaporizer 4;Cracking reaction occurs under the reaction condition of temperature 230 ℃, pressure 0.3 MPa, and hydrogen and carbon monoxide high temperature conversion gas are generated. Figure 1 Wherein, methanol vaporizer 4 and reactor 5 adopt electric heating heat conducting oil to provide heat source.Catalyst is copper-based catalyst.In high temperature conversion gas obtained by methanol direct cracking reaction, hydrogen content is 60%-64%, and carbon monoxide content is 30%-34%.

[0036] The application also provides a methanol cracking hydrogen production system, as shown in the figure, comprising: methanol storage tank 1, methanol metering pump 2, heat exchanger 3, methanol vaporizer 4 and reactor 5 connected in sequence, and outlet pipeline connected to the tail end of reactor 5, and one end of the outlet pipeline is connected to heat exchanger 3 for heat exchange of raw material methanol liquid.

[0037] Figure 1 In the embodiment of the application, as shown in the figure, the system further comprises controller 12, and liquid level transmitter 6 is arranged on methanol storage tank 1 for measuring the remaining amount in methanol storage tank 1 and transmitting the measurement data to controller 12, and when the remaining amount in methanol storage tank 1 is lower than the minimum set value, the controller 12 sends an alarm signal for insufficient amount.

[0038] In the embodiment of the application, as shown in the figure, the system further comprises controller 12, and liquid level transmitter 6 is arranged on methanol storage tank 1 for measuring the remaining amount in methanol storage tank 1 and transmitting the measurement data to controller 12, and when the remaining amount in methanol storage tank 1 is lower than the minimum set value, the controller 12 sends an alarm signal for insufficient amount. Figure 1 In the embodiment of the application, as shown in the figure, pipeline flow meter 7 is arranged on the connecting pipeline between methanol metering pump 2 and heat exchanger 3, first temperature transmitter 8 and first pressure transmitter 9 are arranged on methanol vaporizer 4, second temperature transmitter 10 and second pressure transmitter 11 are arranged on reactor 5, first temperature transmitter 8, first pressure transmitter 9, second temperature transmitter 10 and second pressure transmitter 11 are connected to the input end of controller 12 through signal lines, and the power driving elements of controlled modules are controlled by controller 12, so as to control the process conditions of methanol direct cracking hydrogen production.

[0039] Figure 1 In the embodiment of the application, as shown in the figure, pipeline flow meter 7 is arranged on the connecting pipeline between methanol metering pump 2 and heat exchanger 3, first temperature transmitter 8 and first pressure transmitter 9 are arranged on methanol vaporizer 4, second temperature transmitter 10 and second pressure transmitter 11 are arranged on reactor 5, first temperature transmitter 8, first pressure transmitter 9, second temperature transmitter 10 and second pressure transmitter 11 are connected to the input end of controller 12 through signal lines, and the power driving elements of controlled modules are controlled by controller 12, so as to control the process conditions of methanol direct cracking hydrogen production.

[0040] In the embodiment of the application, as shown in the figure, pipeline flow meter 7 is arranged on the connecting pipeline between methanol metering pump 2 and heat exchanger 3, first temperature transmitter 8 and first pressure transmitter 9 are arranged on methanol vaporizer 4, second temperature transmitter 10 and second pressure transmitter 11 are arranged on reactor 5, first temperature transmitter 8, first pressure transmitter 9, second temperature transmitter 10 and second pressure transmitter 11 are connected to the input end of controller 12 through signal lines, and the power driving elements of controlled modules are controlled by controller 12, so as to control the process conditions of methanol direct cracking hydrogen production. Figure 1 ​​As shown, the controlled module power driving elements include the pump rotor driving element of the methanol metering pump 2, the electric heating wire of the methanol vaporizer 4, the electric heating wire of the reactor 5, and the valve core of the back pressure valve 14 arranged on the outlet pipeline.

[0041] The pipeline flow meter 7 is used to detect the raw material methanol liquid feed amount and transmit the measurement data to the controller 12, the controller 12 compares the received result with the set value, and when the error is large, the controller 12 controls the methanol metering pump 2 rotor speed to adjust the methanol feed amount to the set value. The first temperature transmitter 8, the first pressure transmitter 9, the second temperature transmitter 10 and the second pressure transmitter 11 are respectively used to detect the temperature and pressure inside the equipment, and transmit the measurement data to the controller 12, the controller compares the received result with the set value, when the temperature is inconsistent, the controller 12 controls the corresponding electric heating wire heating power, realizes the accurate control of the temperature; when the pressure is inconsistent, the controller 12 controls the position and opening degree of the valve core of the back pressure valve 14 on the outlet pipeline, realizes the control of the pressure of the methanol direct cracking hydrogen production reaction process system.

[0042] In addition, the controller 12 can also transmit the real-time state of the controlled module to the display terminal 13 through the output end, and display the real-time state information in real time for reference and inquiry, and the display terminal 13 includes one or more of liquid crystal display screen, mobile phone, computer and the like.

[0043] In the embodiment of the present application, optionally, Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 As shown, a rotating drum 15 is arranged at the central position of the connecting pipeline between the methanol vaporizer 4 and the reactor 5, the length direction of the rotating drum 15 is oriented to the axial direction of the connecting pipeline, one end of the rotating drum 15 is rotationally connected with a rotating shaft 16, one end of the rotating shaft 16 penetrates out of the rotating drum 15 and is connected with a rotating blade 17, the rotating blade 17 is similar to the rotating blade of the existing fan and the like, the length direction of the rotating blade 17 is perpendicular to the rotating shaft 16, a plurality of air inlet holes are arranged on the rotating blade 17, the rotating shaft 16 is designed as a hollow structure and is communicated with the air inlet holes, specifically, the rotating blade 17 can also be designed as a hollow structure and is communicated with the air inlet holes and the rotating shaft 16, the other end of the rotating drum 15 is connected with an elastic member 18, the elastic member 18 can adopt the existing conventional elastic components such as springs and the like, one end of the elastic member 18 is connected with an abutting plate 19, the other end of the rotating drum 15 is externally connected with an air outlet pipe 20, one end of the air outlet pipe 20 penetrates out of the connecting pipeline and is connected with an on-off valve 21, when the on-off valve 21 is in the initial closed state, the air outlet pipe 20 is in the state of being closed, and when the on-off valve 21 is in the open state, the air outlet pipe 20 is in the state of being opened. Figure 2 、 Figure 3As shown, the elastic member 18 pushes the abutting plate 19 to make the abutting plate 19 abut against the rotating shaft 16, when the switch valve 21 is opened and the gas is sucked out through the gas outlet pipe 20, specifically, the gas outlet pipe 20 can be externally connected with a small suction pump for generating negative pressure in the gas outlet pipe 20, at this time, as shown in Figure 4 、 Figure 5 As shown, the gas pressure on the side of the abutting plate 19 in the rotating drum 15 close to the gas outlet pipe 20 is obviously smaller than that close to the rotating shaft 16, thereby driving the abutting plate 19 to move away from the rotating shaft 16, and the elastic member 18 is in an elastic compression state, since the rotating shaft 16 loses the limiting effect of the abutting plate 19, the rotating blade 17 can be freely rotated along the direction perpendicular to the gas outlet direction in the connecting pipeline under the action of the gas flow in the connecting pipeline, so that the gas inlet hole on the rotating blade 17 can uniformly collect the gas in the connecting pipeline, and the gas is discharged outwards through the gas inlet hole, the rotating shaft 16 and the gas outlet pipe 20, the gas can be discharged to the gas chromatograph or infrared spectrum detector through the small suction pump, and the methanol concentration in the gas is detected to avoid the influence of impurity gases such as oxygen mixed in on the hydrogen production process.

[0044] Wherein, the switch valve 21 can be intermittently opened according to the actual process requirements to carry out gas detection, during the opening process of the switch valve 21, the gas outlet along the gas inlet hole will not have a great influence on the gas pressure in the connecting pipeline, after the gas detection is completed, the switch valve 21 is closed again, the gas pressures on both sides of the abutting plate 19 in the rotating drum 15 are balanced, and the elastic member 18 elastically pushes the abutting plate 19 to make the abutting plate 19 abut against the rotating shaft 16 to reset; wherein, the end surface of the abutting plate 19 abutting against the rotating shaft 16 can be provided with a conventional frosted surface structure to increase the friction, so that the rotating blade 17 is in a static state in the connecting pipeline when the abutting plate 19 abuts against the rotating shaft 16 to reset, thereby avoiding the influence on the gas pressure in the connecting pipeline, or a spring column and a limiting groove can be relatively arranged on the end surface of the abutting plate 19 abutting against the rotating shaft 16, for example, when the abutting plate 19 abuts against the rotating shaft 16 to reset, the spring column on the abutting plate 19 is turned to the limiting groove position on the rotating shaft 16, and the spring column is inserted into the limiting groove to limit the abutting plate 19, so that the rotating blade 17 is in a static state in the connecting pipeline.

[0045] Wherein, the rotating blade 17 can be provided with two pieces in a linear type along the radial direction of the rotating shaft 16, or can be provided with three or more pieces.

[0046] Those skilled in the art should understand that the above discussion of any embodiment is only exemplary and is not intended to limit the scope of the present application to these examples; under the idea of the present application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the present application as described above. In order to be brief, they are not provided in details.

Claims

1. A methanol cracking process for hydrogen production, characterized in that, Includes the following steps: Methanol feed: Liquid methanol is transported from methanol storage tank (1) to heat exchanger (3) via methanol metering pump (2); Methanol preheating: The raw material methanol liquid is heated to 60-80℃ by heat exchanger (3); Methanol vaporization: The preheated raw material methanol liquid is sent into the methanol vaporizer (4) and vaporized into methanol vapor at a temperature of 180-200℃; Methanol direct cracking: Methanol vapor enters reactor (5) and undergoes cracking reaction under the catalysis of catalyst at a temperature of 230-250℃, generating hydrogen and carbon monoxide high-temperature conversion gas; Methanol cooling: The high-temperature conversion gas is cooled by heat exchanger (3) and then transported to the product end.

2. The methanol cracking hydrogen production process according to claim 1, characterized in that, The methanol vaporizer (4) and reactor (5) are powered by electrically heated heat transfer oil.

3. The methanol cracking hydrogen production process according to claim 1, characterized in that, The catalyst is a copper-based catalyst.

4. The methanol cracking hydrogen production process according to claim 1, characterized in that, The high-temperature conversion gas obtained from the direct cracking reaction of methanol contains 60%-64% hydrogen and 30%-34% carbon monoxide.

5. A methanol cracking hydrogen production system, wherein the system is prepared using the methanol cracking hydrogen production process as described in any one of claims 1-4, characterized in that, include: A methanol storage tank (1), a methanol metering pump (2), a heat exchanger (3), a methanol vaporizer (4), and a reactor (5) are connected in sequence. The tail end of the reactor (5) is connected to an outlet pipe, one end of which is wound around the heat exchanger (3) for heat exchange of the raw material methanol liquid.

6. A methanol cracking hydrogen production system according to claim 5, characterized in that, It also includes a controller (12), and the methanol storage tank (1) is equipped with a level transmitter (6) for measuring the remaining amount in the methanol storage tank (1) and transmitting the measurement data to the controller (12). When the remaining amount in the methanol storage tank (1) is lower than the minimum set value, the controller (12) sends an alarm signal for insufficient remaining amount.

7. A methanol cracking hydrogen production system according to claim 6, characterized in that, A flow meter (7) is installed on the connecting pipe between the methanol metering pump (2) and the heat exchanger (3). A first temperature transmitter (8) and a first pressure transmitter (9) are installed on the methanol vaporizer (4). A second temperature transmitter (10) and a second pressure transmitter (11) are installed on the reactor (5). The first temperature transmitter (8), the first pressure transmitter (9), the second temperature transmitter (10), and the second pressure transmitter (11) are connected to the input terminal of the controller (12) through signal lines. The controller (12) regulates the power drive element of the controlled module, thereby controlling the process conditions for direct methanol cracking to produce hydrogen.

8. A methanol cracking hydrogen production system according to claim 7, characterized in that, The controlled module power drive components include the pump rotor drive of the methanol metering pump (2), the electric heating wire of the methanol vaporizer (4), the electric heating wire of the reactor (5), and the valve core of the back pressure valve (14) installed on the outlet pipeline.

9. A methanol cracking hydrogen production system according to claim 5, characterized in that, A rotating drum (15) is installed at the center of the connecting pipe between the methanol vaporizer (4) and the reactor (5). A rotating shaft (16) is rotatably connected to one end of the rotating drum (15). One end of the rotating shaft (16) extends out of the rotating drum (15) and is connected to a rotating blade (17). Multiple air inlets are provided on the rotating blade (17). The rotating shaft (16) is designed with a hollow structure and is connected to each air inlet. An elastic element (18) is connected to the other end of the rotating drum (15). One end of the elastic element (18) is connected to a stop plate (19). An air outlet pipe (2) is connected to the other end of the rotating drum (15). 0), one end of the outlet pipe (20) extends out of the connecting pipe and is connected to a switch valve (21). When the switch valve (21) is in the initial closed state, the elastic element (18) pushes the abutment plate (19) so that the abutment plate (19) abuts against the rotating shaft (16). When the switch valve (21) opens and draws gas out through the outlet pipe (20), the abutment plate (19) moves laterally away from the rotating shaft (16), and the rotating blade (17) rotates perpendicular to the gas outlet direction in the connecting pipe and blows gas out through the air inlet, rotating shaft (16), and outlet pipe (20) to detect the methanol concentration in the gas.

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