A gasifier heat exchange pipeline and self-pressurizing gasifier thereof

Abstract

The present invention provides a gasifier heat exchange pipeline and a self-pressurized gasifier thereof, wherein the heat exchange pipeline is a spiral pipeline, the cross section of the pipeline is a star-shaped structure, each sharp corner of the star-shaped structure is fixed with a fin arranged along the axis of the heat exchange pipeline, and each side of the star-shaped structure is also provided with a semicircular protrusion arranged along the axis of the heat exchange pipeline. The present invention improves the heat exchange area and heat exchange efficiency by optimizing the pipeline structure, solves the problem of slow air flow exchange in a closed environment, and enables the gasifier to fully exchange heat with the atmosphere during operation.

Description

Technical Field

[0001] The invention relates to a gasifier, in particular to a gasifier heat exchange pipeline and a self-pressurizing gasifier thereof. Background Art

[0002] Nitrogen is an inert gas and is often used as a protector and exhaled gas in industrial production. Therefore, it can also be used as a cooling system. For example, in machining centers and data centers, liquid nitrogen can be pressurized and gasified into nitrogen through a vaporizer and sprayed into the air through a sprayer to achieve a cooling effect.

[0003] At present, for the gasification of cryogenic liquids such as liquid nitrogen, air-temperature vaporizers are generally used in China. Air-temperature vaporizers are a type of finned tube vaporizer that uses the natural convection air in the atmospheric environment as a heat source, and exchanges heat with cryogenic liquids through aluminum finned tubes with good thermal conductivity to vaporize them into gas at a certain temperature. Air-temperature vaporizers rely on their own sensible heat and absorb heat from the external atmospheric environment to work, without the need for additional power and energy consumption. Compared with other vaporizers, air-temperature vaporizers have the advantages of being pollution-free, green and environmentally friendly, safe and simple, easy to maintain, low operating cost, and unrestricted use.

[0004] The core device of the air-temperature vaporizer is the heat exchange pipe, which is to exchange more heat from the smallest possible atmospheric environment to achieve the gasification function. At present, the air-temperature vaporizers produced in China mostly use circular finned tubes made of rust-proof aluminum alloy with good thermal conductivity. Its structure is: the middle of the finned tube is a circular hollow tube, and radial fins are distributed outside the tube. The liquid flows in the middle of the tube, and the fins absorb the heat from the outside atmosphere and transfer it to the tube, so that the droplets are absorbed and gasified. For example, the Chinese patent with announcement number CN211344783U and announcement date 2020.8.25: Double-layer tube vaporizer, which uses commonly used circular finned tubes with low heat exchange efficiency. The heat transfer efficiency of an air-temperature vaporizer is mainly determined by the heat transfer area of ​​the heat transfer pipeline. In order to achieve a certain flow rate and working efficiency, only a design with additional fins can be adopted. Due to the lack of optimized design, most domestic air-temperature vaporizers have the following disadvantages: the equipment is too large and occupies a large space, the cost is too high due to the increase in fins, and the heat transfer efficiency is too low, resulting in insufficient product flow. At the same time, when using an air-temperature vaporizer to vaporize low-temperature liquid as a cooling system, since the working environment is often a closed place, the air flow exchange is relatively slow and difficult, and the heat exchange efficiency between the vaporizer and the atmospheric environment is also poor. Summary of the invention

[0005] The present invention provides a vaporizer heat exchange pipeline and a self-pressurizing vaporizer thereof, which improves the heat exchange area and heat exchange efficiency by optimizing the pipeline structure, solves the problem of slow air flow exchange in a closed environment, and enables the vaporizer to fully exchange heat with the atmosphere during operation.

[0006] The technical solution of the present invention is as follows:

[0007] A gasifier heat exchange pipe, which is a spiral pipe. The cross section of the pipe is a star-shaped structure. Fins arranged along the axial direction of the heat exchange pipe are fixed at each sharp corner of the star-shaped structure, and semicircular protrusions arranged along the axial direction of the heat exchange pipe are also provided on each side of the star-shaped structure.

[0008] The cross-section of the pipeline structure designed in the present invention is star-shaped, fins are distributed at each sharp corner of the pipeline, and circular protrusions are added on the side. The star-shaped pipeline structure increases the contact area between the pipeline and the air, directly increases the heat exchange area of ​​the liquid flow surface, and does not require excessive design and addition of fins. Therefore, the effective heat exchange area between the fins and the air environment is also guaranteed, which can effectively improve the heat exchange efficiency.

[0009] Furthermore, in order to avoid interference between the semicircular protrusions on the adjacent two side edges, the semicircular protrusion is fixed in the middle of the side edge, and the diameter is less than 2 / 3 of the side edge length.

[0010] Further, the number of sides of the star structure is less than 20.

[0011] As the number of sides of the star-shaped structure increases, its outer circumference will continue to increase, and the heat exchange area of ​​the heat exchange pipe will increase accordingly. However, when the number of sides is too many, the raised structure on the side will become smaller, and the heat exchange efficiency of each side in the heat exchange work will also decrease. Therefore, the number of sides of the heat exchange pipe with a star-shaped structure should be controlled within 20 to ensure better heat exchange efficiency.

[0012] Furthermore, the height of the fin is less than 2 / 3 of the inner spiral radius of the heat exchange pipe.

[0013] In order to increase the heat exchange efficiency of the heat exchange pipe, the pipe is designed to rise in a spiral shape. At the same time, in order to avoid the fins distributed on the inner side of the spiral pipe from touching each other, the height of the fins on the inner side of the spiral pipe should be reduced accordingly according to the radius of the inner spiral, and the fin height should not exceed 2 / 3 of the inner spiral radius to ensure the contact and heat exchange between the side wall of the inner side of the spiral pipe and the air; the fins distributed on the outer side of the spiral pipe are in more sufficient contact with the convective air, serving as the main fins for heat exchange with the environment. At the same time, the height of the fins will not affect the heat exchange between the outer wall of the pipe and the air, so the fin height can be lengthened according to the occupied space.

[0014] Furthermore, the semicircular protrusion is integrally formed with the heat exchange pipe.

[0015] Furthermore, the spiral length L of the heat exchange pipe needs to make the total heat absorption Q of the heat exchange pipe from the working environment equal to the heat absorption Q1 of liquid nitrogen converted into nitrogen through the heat exchange pipe.

[0016] The spiral length of the heat exchange pipe should be designed so that the liquid nitrogen can be completely gasified after passing through the heat exchange pipe. Therefore, the total heat absorption Q of the heat exchange pipe from the working environment needs to be equal to the heat absorption Q1 of the liquid nitrogen converted into nitrogen through the heat exchange pipe.

[0017] Furthermore, assuming that the air temperature that the heat exchange pipe contacts during operation remains unchanged, that is, the heat transfer coefficient with the air remains unchanged, the total amount of heat absorbed by the heat exchange pipe from the working environment, Q, is:

[0018]

[0019] Where: K is the total heat transfer coefficient, F1 is the surface circumference of the heat exchange pipe, T A is the ambient temperature, T0 is the nitrogen saturation temperature, and T is the liquid nitrogen temperature;

[0020] The calculation formula of the overall heat transfer coefficient K is:

[0021]

[0022] Where: δ is the wall thickness of the heat exchange pipe, λ is the thermal conductivity of the pipe, η is the heat transfer efficiency of the fin, α A is the heat transfer coefficient between the tube and air, F2 is the total area of ​​the fin;

[0023] Among them, the derivation formulas of F1 and F2 are:

[0024] F1=πD i ·L

[0025] F2=(πD o -N·x+2N·y)·L

[0026] Where: L is the spiral length of the heat exchange pipe, D i D is the diameter of the inscribed circle of the heat exchange pipe. o is the circumscribed circle diameter of the heat exchange pipe, N is the number of fins, x is the fin thickness, and y is the fin height;

[0027] The heat absorbed by liquid nitrogen when converted into nitrogen gas is Q1:

[0028] Q1=M·(S+C p ·ΔT)

[0029] Where: M is the mass of liquid nitrogen, S is the heat of liquid nitrogen vaporization, C p is the specific heat capacity of nitrogen at constant pressure, ΔT is the temperature rise of nitrogen;

[0030] Since the total heat absorption Q is equal to the heat absorption, then:

[0031]

[0032] Substituting into the calculation formula of F1 and F2, we get:

[0033]

[0034] The spiral length L of the heat exchange pipe is calculated according to the above formula.

[0035] The present invention also provides a self-pressurizing gasifier, comprising the above-mentioned heat exchange pipe, an input pipeline and an output pipeline, wherein the input pipeline is connected to the inlet of the heat exchange pipe, the outlet of the heat exchange pipe is connected to one end of the output pipeline, and the other end of the output pipeline is provided with a nozzle.

[0036] Furthermore, the gasifier is also provided with a controller, a flow control valve is provided between the input pipeline and the inlet of the heat exchange pipeline, a temperature sensor and a pressure sensor are provided on the output pipeline, and the flow control valve, temperature sensor and pressure sensor are all electrically connected to the controller.

[0037] Liquid nitrogen is transported from the input pipeline to the heat exchange pipeline, and a flow control valve is installed at the connection. When the liquid nitrogen absorbs heat and heats up in the heat exchange pipeline and is completely vaporized, it is finally vaporized into nitrogen and output through the output pipeline, and the nozzle increases the nitrogen ejection flow rate. The temperature sensor and pressure sensor installed in the output pipeline monitor the pressure and temperature of the output nitrogen in real time, and feed back the signal to the controller according to the required pressure. The controller controls the flow control valve, and then regulates the flow of liquid nitrogen, and finally makes the nitrogen ejected through the nozzle reach the required temperature and pressure. The real-time monitoring of nitrogen by the pressure sensor and temperature sensor at the outlet allows the controller and the flow controller at the inlet to be controlled, and can be regulated according to the required nitrogen pressure and temperature, so that the vaporized nitrogen can meet more work needs and has a wider range of applications.

[0038] Furthermore, the gasifier is also provided with a blowing device, which is electrically connected to the controller and is used to generate convection air and blow it toward the heat exchange pipe.

[0039] The air convection in the working environment of the vaporizer is mainly regulated by the blowing device in the working environment. The convection air generated by the blowing device can ensure that the atmospheric temperature contacted by the heat exchange pipe is maintained within a stable range, thereby ensuring the stability of the heat exchange efficiency of the vaporizer.

[0040] The beneficial effects of the present invention are:

[0041] The present invention changes the existing circular pipe into a star-shaped pipe structure with a semicircular protrusion, increases the heat exchange area and improves the heat exchange efficiency by changing the pipe structure, does not need to increase too many radial fins, greatly reduces the production cost, and reduces the volume. While increasing the heat exchange area, it also increases the flow rate of the pipe, and improves the working efficiency of the gasifier. At the same time, the self-pressurized gasifier using the heat exchange pipe can adjust the pressure and temperature of the gasified nitrogen to the required value by adjusting the flow control valve of the input liquid nitrogen according to the required working nitrogen temperature and pressure, so that the gasified nitrogen can meet more work requirements and has a wider range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a cross-sectional schematic diagram of an existing circular finned pipe;

[0043] Figure 2 is a cross-sectional schematic diagram of a heat exchange pipeline of the present invention;

[0044] Figure 3 It is a schematic diagram of the working principle of the gasifier of the present invention;

[0045] In the figure: heat exchange pipe 1, side 101, fin 2, semicircular protrusion 3, input pipeline 4, output pipeline 5, nozzle 6, blowing device 7, flow control valve 8, temperature sensor 9, pressure sensor 10. DETAILED DESCRIPTION

[0046] The drawings are only for illustrative purposes and cannot be construed as limiting the present invention. To better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged, or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the drawings. The positional relationships described in the drawings are only for illustrative purposes and cannot be construed as limiting the present invention.

[0047] The pipeline structure of the air-temperature gasifier currently produced in China is as follows: Figure 1 As shown, the center of the pipe is circular, and radial fins 2 are distributed in a star shape around the circular pipe. In order to increase the heat exchange area of ​​the pipe and improve the heat exchange efficiency, the method of adding fins 2 is usually adopted. However, when too many fins 2 are distributed in the pipe, the effective contact area between a single fin 2 and the air is reduced. The effect of increasing the number of fins 2 in improving the heat exchange efficiency becomes less, and the production cost will be higher.

[0048] Embodiment 1:

[0049] like Figure 2 and Figure 3As shown, the present invention provides a heat exchange pipe, the heat exchange pipe 1 is a spiral pipe, the cross section of the pipe is a star-shaped structure, each sharp corner of the star-shaped structure is fixed with a fin 2 arranged along the axial direction of the heat exchange pipe 1, and each side 101 of the star-shaped structure is also provided with a semicircular protrusion 3 arranged along the axial direction of the heat exchange pipe 1, and the semicircular protrusion 3 is integrally formed with the heat exchange pipe 1.

[0050] The star-shaped pipe structure increases the contact area between the pipe and the air, directly increasing the heat exchange area of ​​the liquid flow surface without the need to design too many fins 2. Therefore, the effective heat exchange area between the fins 2 and the air environment is also guaranteed, which can effectively improve the heat exchange efficiency.

[0051] Comparing the heat dissipation area of ​​the existing finned circular pipe and the star-shaped pipe structure of the present invention, when the number of fins 2 is the same, that is, comparing the outer perimeter of the cross section when the two occupy the same space, the outer circle of the circular pipe is used as the circumscribed circle to calculate the perimeter of the heat exchange pipe of the present invention. The total perimeter calculation process of the heat exchange pipe 1 is as follows:

[0052] First calculate the length of the side 101 of the star:

[0053] known;

[0054] L 2 =2X 2

[0055] X 2 +L 2 =R 2

[0056] Where: L is the length of the side 101 of the star, X is half the length of the distance between the two corners of the star, and R is the radius of the circumscribed circle;

[0057] We can get:

[0058]

[0059] Therefore, the total circumference of the star structure is Where n is the number of sides 101 of the star;

[0060] At the same time, a semicircular protrusion 3 is distributed on each side 101 of the heat exchange pipe 1, so the total circumference of the heat exchange pipe 1 is:

[0061] L2=L1-nR1+nπR1

[0062] Wherein: R1 is the diameter of the semicircular protrusion 3.

[0063] When designing the semicircular protrusion 3 on the side 101, in order to avoid interference between the semicircular protrusions 3 on the adjacent two sides 101, the diameter of the semicircular protrusion 3 should be less than 2 / 3 of the length of the side 101;

[0064] Therefore, in the same space size, that is, when the diameter of the circumscribed circle of the star-shaped structure of the present invention is the same as that of the existing circular pipe structure, the increase in the total circumference of the heat exchange pipe 1 of the present invention is:

[0065]

[0066] It can be known from the above calculation formula that as the number of sides 101 of the star-shaped structure increases, the total circumference of the heat exchange pipe 1 will continue to increase, and the heat exchange area will increase accordingly. However, when the number of sides is too many, the semicircular protrusion 3 structure on the side will also become smaller, and the heat exchange efficiency of each side 101 in the heat exchange work will also decrease. Therefore, the number of sides 101 of the heat exchange pipe 1 with a star-shaped structure should be controlled within 20 to ensure better heat exchange efficiency.

[0067] In this embodiment, in order to increase the heat exchange efficiency of the heat exchange pipe 1, the pipe rises in a spiral shape. Therefore, in the design and processing of the pipe, it is necessary to avoid the fins 2 distributed on the inner side of the spiral pipe from touching each other. The height of the fins 2 on the inner side of the spiral pipe should be reduced accordingly according to the radius of the inner spiral. The height of the fins 2 should not exceed 2 / 3 of the radius of the inner spiral to ensure the contact and heat exchange between the side wall of the inner side of the spiral pipe and the air; and the fins 2 distributed on the outer side of the spiral pipe are in more sufficient contact with the convective air, serving as the main fins for heat exchange with the environment. At the same time, the height of the fins 2 will not affect the heat exchange between the outer wall of the pipe and the air, so the height of the fins 2 can be lengthened according to the occupied space.

[0068] In this embodiment, because the cross-sectional structure of the pipe is a complex graphic and has a large number of semicircular structures, structural deformation caused by extrusion or stretching must be avoided during the pipe bending process. When making spiral bent pipes, an anti-wrinkle mold is installed to prevent structural deformation during the bending process. At the same time, the heat exchange pipe is bent according to the pre-designed fin spacing on the inside of the spiral pipe.

[0069] In this embodiment, the spiral length L of the heat exchange pipe 1 is designed to allow the liquid nitrogen to be completely gasified after passing through the heat exchange pipe 1. Therefore, the total heat absorption Q of the heat exchange pipe 1 from the working environment needs to be equal to the heat absorption Q1 of the liquid nitrogen absorbed by the heat exchange pipe 1 and converted into nitrogen.

[0070] The spiral length design process of the heat exchange pipe 1 is as follows:

[0071] Assuming that the air temperature that the heat exchange pipe 1 contacts during operation remains unchanged, that is, the heat transfer coefficient with the air remains unchanged, the total amount of heat absorbed by the heat exchange pipe 1 from the working environment, Q, is:

[0072]

[0073] Where: K is the total heat transfer coefficient, F1 is the surface circumference of the heat exchange pipe 1, T A is the ambient temperature, T0 is the nitrogen saturation temperature, and T is the liquid nitrogen temperature;

[0074] The calculation formula of the overall heat transfer coefficient K is:

[0075]

[0076] Where: δ is the wall thickness of the heat exchange pipe 1, λ is the thermal conductivity of the pipe, η is the heat transfer efficiency of the fin, α A is the heat transfer coefficient between the tube and air, F2 is the total area of ​​the fin;

[0077] Among them, the derivation formulas of F1 and F2 are:

[0078] F1=πD i ·L

[0079] F2=(πD o -N·x+2N·y)·L

[0080] Where: L is the spiral length of the heat exchange pipe 1, D i is the diameter of the inscribed circle of the heat exchange pipe 1, D o is the diameter of the circumscribed circle of the heat exchange pipe 1, N is the number of fins 2, x is the thickness of fins 2, and y is the height of fins 2;

[0081] The heat absorbed by liquid nitrogen when converted into nitrogen gas is Q1:

[0082] Q1=M·(S+C p ·ΔT)

[0083] Where: M is the mass of liquid nitrogen, S is the heat of liquid nitrogen vaporization, C p is the specific heat capacity of nitrogen at constant pressure, ΔT is the temperature rise of nitrogen;

[0084] Since the total heat absorption Q is equal to the heat absorption, then:

[0085]

[0086] Substituting into the calculation formula of F1 and F2, we get:

[0087]

[0088] According to the above formula, it can be calculated that the spiral length L of the heat exchange pipe 1 can be completely gasified after the liquid nitrogen passes through the heat exchange pipe 1 for heat exchange.

[0089] See also Figure 3The present invention also provides a self-pressurizing gasifier, comprising the above-mentioned heat exchange pipe 1, input pipe 4 and output pipe 5, the input pipe 4 is connected to the inlet of the heat exchange pipe 1, the outlet of the heat exchange pipe 1 is connected to one end of the output pipe 5, and the other end of the output pipe 5 is provided with a nozzle 6; the gasifier is also provided with a blowing device 7, the blowing device 7 is used to generate convection air and blow it to the heat exchange pipe 1; the gasifier is also provided with a controller (not shown in the figure), a flow control valve 8 is provided between the input pipe 4 and the inlet of the heat exchange pipe 1, a temperature sensor 9 and a pressure sensor 10 are provided on the output pipe 5, and the blowing device 7, the flow control valve 8, the temperature sensor 9 and the pressure sensor 10 are all electrically connected to the controller.

[0090] The working principle diagram of the gasifier is as follows Figure 3 As shown, the air convection in the working environment of the gasifier is mainly regulated by the blowing device 7 in the working environment. The convection air generated by the blowing device 7 can ensure that the atmospheric temperature contacted by the heat exchange pipe 1 is maintained within a stable range, thereby ensuring the stability of the heat exchange efficiency of the gasifier. Liquid nitrogen is transported to the heat exchange pipe 1 by the input pipeline 4. A flow control valve 8 is installed at the connection between the heat exchange pipe 1 and the input pipeline 4. The spiral length of the heat exchange pipe 1 is obtained by pre-design. The pipe is distributed in a spiral rise, which fully meets the contact between the heat exchange pipe 1 and the air. The liquid nitrogen absorbs heat in the heat exchange pipe 1 and gasifies into nitrogen. The air pressure rises, and the nitrogen flows to the outlet of the output pipe 5. The outlet of the output pipe 5 is connected with a nozzle 6 for spraying nitrogen. A temperature sensor 9 and a pressure sensor 10 are installed in the output pipe 5 to monitor the temperature and pressure of the nitrogen in real time. At the same time, the sensor feeds back a signal to the controller. The controller adjusts the flow rate of the input liquid nitrogen through the flow control valve 8 according to the required working nitrogen temperature and pressure to regulate the pressure and temperature of the gasified nitrogen to reach the required values, so that the gasified nitrogen can meet more work requirements and has a wider range of applications.

[0091] Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A self-pressurizing gasifier, characterized in that: It comprises a heat exchange pipeline (1), an input pipeline (4) and an output pipeline (5), wherein the input pipeline (4) is connected to the inlet of the heat exchange pipeline (1), the outlet of the heat exchange pipeline (1) is connected to one end of the output pipeline (5), and the other end of the output pipeline (5) is provided with a nozzle (6); A controller is also provided, a flow control valve (8) is provided between the input pipeline (4) and the inlet of the heat exchange pipeline (1), a temperature sensor (9) and a pressure sensor (10) are provided on the output pipeline (5), and the flow control valve (8), the temperature sensor (9) and the pressure sensor (10) are all electrically connected to the controller; The heat exchange pipe (1) is a spiral pipe, and the cross section of the pipe (1) is a star-shaped structure. A fin (2) arranged along the axis of the heat exchange pipe (1) is fixed at each sharp corner of the star-shaped structure, and each side (101) of the star-shaped structure is also provided with a semicircular protrusion (3) arranged along the axis of the heat exchange pipe (1). The semicircular protrusion (3) is fixed at the middle of the side (101) and has a diameter less than 2 / 3 of the length of the side (101). The number of the sides (101) of the star-shaped structure is less than 20, and the height of the fin (2) is less than 2 / 3 of the inner spiral radius of the heat exchange pipe (1).

2. A self-pressurizing gasifier according to claim 1, characterized in that: The semicircular protrusion (3) and the heat exchange pipe (1) are integrally formed.

3. The self-pressurizing gasifier according to claim 1, characterized in that: The spiral length L of the heat exchange pipe (1) needs to ensure that the total amount of heat absorbed Q by the heat exchange pipe (1) from the working environment is equal to the amount of heat absorbed Q1 by liquid nitrogen converted into nitrogen through the heat exchange pipe (1).

4. A self-pressurizing gasifier according to claim 3, characterized in that: Assuming that the temperature of the air that the heat exchange pipe (1) contacts during operation remains constant, that is, the heat transfer coefficient with the air remains constant, the total amount of heat absorbed by the heat exchange pipe (1) from the working environment, Q, is: Where: K is the total heat transfer coefficient, F1 is the surface circumference of the heat exchange pipe (1), T A is the ambient temperature, T0 is the nitrogen saturation temperature, and T is the liquid nitrogen temperature; The calculation formula of the overall heat transfer coefficient K is: Where: δ is the wall thickness of the heat exchange pipe (1), λ is the thermal conductivity of the pipe, η is the heat transfer efficiency of the fin (2), α A is the heat transfer coefficient between the tube and air, F2 is the total area of ​​the fin (2); Among them, the derivation formulas of F1 and F2 are: F1=πD i ·L <h2 style=";text-align:left;direction:ltr">F2 = (πD<h2 style=";text-align:left;direction:ltr"> o <h2 style=";text-align:left;direction:ltr"> (-N·x+2N·y)·L Where: L is the spiral length of the heat exchange pipe (1), D i is the diameter of the inscribed circle of the heat exchange pipe (1), D o is the diameter of the circumscribed circle of the heat exchange pipe (1), N is the number of fins (2), x is the thickness of the fins (2), and y is the height of the fins (2); The heat absorbed by liquid nitrogen when converted into nitrogen gas is Q1: Q1=M·(S+C p ·ΔT) Where: M is the mass of liquid nitrogen, S is the heat of liquid nitrogen vaporization, C p is the specific heat capacity of nitrogen at constant pressure, ΔT is the temperature rise of nitrogen; Since the total heat absorption Q is equal to the heat absorption, then: Substituting into the calculation formula of F1 and F2, we get: The spiral length L of the heat exchange pipe (1) is calculated according to the above formula.

5. The self-pressurizing gasifier according to claim 1, characterized in that: A blowing device (7) is also provided. The blowing device (7) is electrically connected to the controller and is used to generate convective air and blow it toward the heat exchange pipe (1).

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