Waste heat recovery evaporator suitable for high-hydrogen-content flue gas

Abstract

The utility model discloses a waste heat recovery evaporator suitable for high-hydrogen-content flue gas, which relates to the technical field of waste heat recovery, and comprises an evaporator body, the evaporator body comprises a horizontal smoke tube type flue gas channel cylinder, a flue gas circulation pipeline is arranged in an inner cavity of the flue gas channel cylinder, two ends of the flue gas circulation pipeline are respectively provided with a sealing head, and the sealing heads are respectively provided with an air inlet and an air outlet. The outer surface of the flue gas circulation pipeline is welded to the two ports of the flue gas channel barrel in a sealed mode through sealing heads, and an economizer body is arranged at one end of the outer wall of the flue gas circulation pipeline. Working medium water in the inner cavity of the flue gas channel cylinder can cool the flue gas circulation pipeline for conveying high-temperature hydrogen-containing waste heat flue gas, so that the water can be changed into a steam-water mixture after absorbing heat, and then steam leaves the waste heat evaporator after passing through the steam-water separation equipment and the steam outlet and is supplied to external steam utilization equipment. And it is guaranteed that the smoke temperature can be reduced, steam can be obtained, energy can be well utilized, and energy is saved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a waste heat recovery technical field, concretely relates to a waste heat recovery evaporator suitable for high hydrogen-containing flue gas. BACKGROUND

[0002] In the chemical production process, a large amount of hydrogen-containing tail gas will be produced, which mainly includes hydrogen (H2), natural gas (CH4) and a small amount of nitrogen (N2); these tail gas usually has a high temperature, if directly discharged, not only will cause great waste of energy, and due to the flammable and explosive characteristics of hydrogen, the random discharge of tail gas also has a security risk; at the same time, when the traditional waste heat recovery equipment is used to treat hydrogen-containing flue gas, hydrogen is easy to cause hydrogen embrittlement phenomenon (i.e. hydrogen atoms dissolved in steel diffuse and gather in the metal to form hydrogen molecules, which leads to material embrittlement and forms fine cracks, which is called hydrogen embrittlement) when contacting with carbon steel, which leads to shortening of equipment life and decline of safety performance, and is difficult to meet the needs of industrial production for efficient and safe waste heat recovery. SUMMARY

[0003] The utility model aims at providing a waste heat recovery evaporator suitable for high hydrogen-containing flue gas to solve the problems raised in the above background technology.

[0004] To solve the above technical problems, the utility model adopts the technical scheme of:

[0005] A waste heat recovery evaporator suitable for high hydrogen-containing flue gas, comprising an evaporator body, the evaporator body comprises a flue gas passage cylinder in a horizontal flue gas pipe type, the inner cavity of the flue gas passage cylinder is provided with a flue gas flow pipe, the two ends of the flue gas flow pipe are respectively provided with end caps, the outer surface of the flue gas flow pipe is respectively sealed and welded with the two ends of the flue gas passage cylinder through the end caps, and one end of the outer wall of the flue gas flow pipe is provided with an economizer body, the two ends of the economizer body are respectively sealed and welded with the outer wall of the flue gas flow pipe through the end caps, and the top of the flue gas passage cylinder is provided with a first feed water inlet and a steam outlet which are communicated with the inner cavity of the flue gas passage cylinder, the top of the economizer body is provided with a second feed water inlet and a water outlet which are communicated with the inner cavity of the economizer body, and the top of the flue gas flow pipe is provided with a steam-water separation device located in the inner cavity of the flue gas passage cylinder.

[0006] Preferably, the inner cavity of the flue gas passage cylinder is provided with a pressure receiving plate which is integrally formed with the flue gas passage cylinder, and the material of the flue gas passage cylinder is Q345R.

[0007] Preferably, the material of the flue gas flow pipe and the end cap is alloy steel.

[0008] Preferably, flanges are arranged at the flue gas inlet and the flue gas outlet of the flue gas flow channel pipe respectively, and the two flanges are connected with corresponding sealing heads respectively.

[0009] Preferably, the steam-water separation device is a perforated plate separator.

[0010] Preferably, the bottom of the flue gas passage cylinder is provided with a drain port and two bottom blow-off ports in communication with the inner cavity of the flue gas passage cylinder, and the two bottom blow-off ports are symmetrically arranged with the drain port as the axis of symmetry.

[0011] Preferably, the outer wall of the flue gas passage cylinder is provided with a low liquid level alarm switch group, a high liquid level alarm switch group, a magnetic flap liquid level meter group and a liquid level transmitter group, and the low liquid level alarm switch group, the high liquid level alarm switch group, the magnetic flap liquid level meter group and the liquid level transmitter group are sequentially arranged from left to right.

[0012] Preferably, the outer wall of the flue gas passage cylinder is provided with an outer wall blow-off port and a dosing port, the outer wall blow-off port is located at the left side of the low liquid level alarm switch group, and the dosing port is located at the right side of the liquid level transmitter group.

[0013] Preferably, the top of the flue gas passage cylinder is provided with a safety valve interface and a gas discharge port, and the gas discharge port is in communication with the inner cavity of the flue gas passage cylinder.

[0014] Preferably, the bottom of the flue gas passage cylinder and the bottom of the economizer body are respectively provided with support seats.

[0015] Due to the adoption of the above technical scheme, the present application has the following technical progress compared with the prior art:

[0016] 1. The present application provides a waste heat recovery evaporator suitable for high hydrogen-containing flue gas, in order to solve the problem of energy waste caused by direct discharge of hydrogen-containing tail gas. By injecting working water into the inner cavity of the flue gas passage cylinder, the working water can cool the flue gas flow channel pipe conveying high-temperature hydrogen-containing waste heat flue gas, so that the water can be changed into a steam-water mixture after absorbing heat, and then the steam passes through the steam-water separation device and the steam outlet to leave the waste heat evaporator and supply to external steam-using equipment, ensuring that the device can not only reduce the flue gas temperature, but also effectively utilize the steam energy and save energy.

[0017] 2. The present application provides a waste heat recovery evaporator suitable for high hydrogen-containing flue gas, in order to solve the problem of hydrogen embrittlement phenomenon during the treatment of hydrogen-containing flue gas by the existing waste heat recovery equipment. By using alloy steel material to manufacture the flue gas flow channel pipe and the sealing head, the hydrogen gas in the flue gas flow channel pipe can be effectively prevented from contacting with carbon steel when the hydrogen-containing tail gas is conveyed through the inner cavity of the flue gas flow channel pipe, thereby effectively avoiding the hydrogen embrittlement phenomenon and solving the explosion problem caused by hydrogen-containing flue gas leakage, so as to ensure the long-term use and safe operation of the equipment, and has high practical value. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0019] Figure 2 This is a schematic diagram of the right-side cross-sectional structure of the flue gas passage cylinder of this utility model.

[0020] In the diagram: 1. Flue gas passage cylinder; 2. Flue gas circulation pipe; 3. End cap; 4. Economizer body; 5. First feedwater inlet; 6. Steam outlet; 7. Second feedwater inlet; 8. Water outlet; 9. Steam-water separator; 10. Pressure plate; 11. Flange; 12. Drain outlet; 13. Bottom drain outlet; 14. Low level alarm switch group; 15. High level alarm switch group; 16. Magnetic level gauge group; 17. Level transmitter group; 18. External drain outlet; 19. Chemical dosing port; 20. Safety valve interface; 21. Vent outlet; 22. Support base; 100. Evaporator body. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to embodiments:

[0022] like Figures 1-2 As shown, this utility model provides a waste heat recovery evaporator suitable for high-hydrogen-content flue gas, including an evaporator body 100. The evaporator body 100 includes a horizontal flue gas channel cylinder 1. The inner cavity of the flue gas channel cylinder 1 is provided with a flue gas flow pipe 2. End caps 3 are respectively provided at both ends of the flue gas flow pipe 2. The outer surface of the flue gas flow pipe 2 is sealed and welded to the two ends of the flue gas channel cylinder 1 through the end caps 3. The sealed welding connection ensures the airtight isolation between the flue gas flow pipe 2 and the working fluid water. To prevent hydrogen from leaking to the working fluid water side and the external environment, an economizer body 4 is provided at one end of the outer wall of the flue gas flow pipe 2. The two ends of the economizer body 4 are sealed and welded to the outer wall of the flue gas flow pipe 2 through end caps 3. The top of the flue gas channel cylinder 1 is provided with a first water inlet 5 and a steam outlet 6 communicating with its inner cavity. The top of the economizer body 4 is provided with a second water inlet 7 and a water outlet 8 communicating with its inner cavity. The top of the flue gas flow pipe 2 is provided with a steam-water separation device 9 located in the inner cavity of the flue gas channel cylinder 1.

[0023] Furthermore, the inner cavity of the flue gas passage cylinder 1 is provided with a pressure plate 10 integrally formed with the flue gas passage cylinder 1. The flue gas passage cylinder 1 is made of Q345R material. The flue gas flow pipe 2 is set on the pressure plate 10. The connection between the flue gas flow pipe 2 and the flue gas passage cylinder 1 made of Q345R is a sealed welding process, which effectively ensures the sealing performance in the high temperature and high pressure hydrogen-containing environment, prevents hydrogen from leaking to the working fluid water side and the external environment, thereby extending the service life of the equipment and ensuring the safe operation of the system.

[0024] Further, the material of the flue gas flow pipe 2 and the head 3 is alloy steel, when the hydrogen-containing tail gas passes through the alloy steel pipe (12CrMoVG) made of alloy steel material, it ensures that hydrogen does not contact carbon steel, which can effectively avoid the hydrogen embrittlement phenomenon, and the head 3 is made of alloy steel (12CrMoV) material, which further avoids the problem of flue gas leakage.

[0025] As shown in Figure 1 , flanges 11 are arranged at the flue gas inlet and the flue gas outlet of the flue gas flow pipe 2, respectively, and the two flanges 11 are connected with the corresponding head 3, respectively. The setting of the flanges 11 can be used for connecting other equipment components of the evaporator, thereby ensuring that a complete and sealed system is formed between the evaporator and the external equipment, and promoting the high-temperature hydrogen-containing waste heat flue gas to enter other process equipment after cooling.

[0026] It should be noted that the present application aims to protect the evaporator which can reduce the flue gas temperature, obtain steam, thereby better save energy, and also solve the explosion problem caused by hydrogen-containing flue gas leakage, therefore, how to connect with other process equipment is not described in detail in this paper, although it is not described in detail in this paper, but its application and mode of connection with other process equipment are known and applied by those skilled in the art.

[0027] Further, as shown in Figure 2 , the steam-water separation device 9 is a perforated plate separator, through the setting of the steam-water separation device 9, the steam in the flue gas passage cylinder 1 can leave the waste heat evaporator after passing through the steam-water separation device 9, and then be supplied to the external steam equipment through the steam outlet 6, thereby ensuring that the quality of the separated steam meets the strict requirements of the subsequent steam equipment, improving the efficiency and quality of energy recycling; It should be noted that the steam-water separation device 9 mentioned in this paper uses existing technical equipment, and the present scheme does not improve the structure of it, and the equipment is known to those skilled in the art, therefore, this paper does not elaborate on it.

[0028] As shown in Figure 1As shown, the bottom of the flue gas passage cylinder 1 is provided with a drain opening 12 and two bottom blowdown openings 13 communicating with the inner cavity thereof, the two bottom blowdown openings 13 are symmetrically arranged with the drain opening 12 as the axis of symmetry, the outer wall of the flue gas passage cylinder 1 is provided with a low liquid level alarm switch group 14, a high liquid level alarm switch group 15, a magnetic flap liquid level meter group 16 and a liquid level transmitter group 17, the low liquid level alarm switch group 14, the high liquid level alarm switch group 15, the magnetic flap liquid level meter group 16 and the liquid level transmitter group 17 are sequentially arranged from left to right, the outer wall of the flue gas passage cylinder 1 is provided with an outer wall blowdown opening 18 and a dosing opening 19, the outer wall blowdown opening 18 is located at the left side of the low liquid level alarm switch group 14, and the dosing opening 19 is located at the right side of the liquid level transmitter group 17, the top of the flue gas passage cylinder 1 is provided with a safety valve interface 20 and a gas vent 21, and the gas vent 21 communicates with the inner cavity of the flue gas passage cylinder 1.

[0029] Specifically, the flue gas passage cylinder 1 is provided with the above-described components, which can realize real-time monitoring of the state of the working medium water, ensure that each component can cooperate in time to realize automatic control and adjustment, ensure the stable and safe operation of the waste heat evaporator equipment, and it is worth noting that the above components can be installed and set by the person skilled in the art according to the actual working condition, and finally the scheme can not only reduce the flue gas temperature, but also save energy and steam, and can also avoid the explosion problem caused by hydrogen-containing flue gas leakage due to unstable operation of the waste heat evaporator equipment.

[0030] Further, the flue gas passage cylinder 1 and the bottom of the economizer body 4 are respectively provided with support seats 22, which can effectively ensure the stability of the horizontal structure of the flue gas passage cylinder 1 and the economizer body 4.

[0031] The working principle of the waste heat recovery evaporator suitable for high hydrogen-containing flue gas will be described in detail below.

[0032] As Figures 1-2As shown, in use, the hydrogen-containing tail gas enters the drain 12 through the flange 11 at one end of the flue gas flow pipe 2, during which the inner cavity of the flue gas passage cylinder 1 can inject the working medium water through the first water inlet 5, and the inner cavity of the economizer body 4 can inject a large amount of working medium water through the second water inlet 7, so that the working medium water of the flue gas passage cylinder 1 can cool the flue gas flow pipe 2 conveying high-temperature hydrogen-containing waste heat flue gas, so that the water can be changed into a steam-water mixture after absorbing heat, and then the steam leaves the waste heat evaporator through the steam-water separation device 9 and the steam outlet 6, and is supplied to the steam-using equipment outside, so that the device can not only reduce the flue gas temperature, but also better utilize the energy and save energy; and since the flue gas flow pipe 2 and the head 3 are made of alloy steel material, the hydrogen in the flue gas flow pipe 2 can be effectively prevented from contacting the carbon steel, the hydrogen embrittlement phenomenon is effectively avoided, the long-term use and safe operation of the device are ensured, and the device has high practical value; and the cooled flue gas can be used in other process equipment through the flange 11 at the other end of the flue gas flow pipe 2, and the flue gas can be further cooled through the second water inlet 7 and the water outlet 8 before entering.

[0033] It should be noted that the waste heat recovery evaporator provided in the present scheme needs to meet the following parameters during operation: the design temperature of the inlet exhaust gas is 500℃, the design inlet exhaust gas amount is 1000Nm 3 / h, the inlet flue gas pressure is -600Pa, the H2 content in the flue gas is 0.85%, the CH4 content is 0.1%, the N2 content is 0.05%, the dust concentration at the inlet is not accumulated when the flow rate is >4m / s, the feed water temperature of the main steam section is 85℃, the steam pressure is 0.6MPa(g), the steam temperature is in a saturated state, the calculated evaporation amount is 0.175t / h, the circulation mode is natural circulation, the exhaust gas temperature is 200℃, the calculated thermal efficiency is 58.7%, the exhaust gas resistance is <300Pa, the air leakage coefficient is 0, the heating surface form is a smoke tube heat exchanger, and the boiler structure form is a horizontal arrangement.

[0034] It should be noted that in the description of the present disclosure, it should be noted that unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above-mentioned terms in the present disclosure can be understood according to the specific circumstances.

[0035] The utility model has made the detailed description to the utility model generally above, but can make some modification or improvement to it on the basis of the utility model, and this is obvious to the general skilled person in the technical field. Therefore, the modification or improvement without departing from the utility model's thought spirit, all are within the utility model's protection scope.

Claims

1. A waste heat recovery evaporator suitable for high-hydrogen-content flue gas, characterized in that: The device includes an evaporator body, which comprises a horizontal flue gas passage cylinder. The inner cavity of the flue gas passage cylinder is provided with a flue gas flow pipe. Both ends of the flue gas flow pipe are respectively provided with end caps. The outer surfaces of the flue gas flow pipe are sealed and welded to the two ends of the flue gas passage cylinder through the end caps. An economizer body is provided at one end of the outer wall of the flue gas flow pipe. The two ends of the economizer body are sealed and welded to the outer wall of the flue gas flow pipe through end caps. The top of the flue gas passage cylinder is provided with a first water inlet and a steam outlet communicating with its inner cavity. The top of the economizer body is provided with a second water inlet and a water outlet communicating with its inner cavity. A steam-water separation device is located within the inner cavity of the flue gas passage cylinder at the top of the flue gas flow pipe.

2. The waste heat recovery evaporator suitable for high hydrogen content flue gas according to claim 1, characterized in that: The inner cavity of the flue gas passage cylinder is provided with a pressure plate integrally formed with the flue gas passage cylinder, and the flue gas passage cylinder is made of Q345R.

3. The waste heat recovery evaporator suitable for high-hydrogen-content flue gas according to claim 1, characterized in that: The flue gas circulation pipe and the end cap are both made of alloy steel.

4. A waste heat recovery evaporator suitable for high-hydrogen-content flue gas according to claim 1, characterized in that: Flanges are installed at the flue gas inlet and flue gas outlet of the flue gas circulation duct, and the two flanges are respectively connected to the corresponding end caps.

5. A waste heat recovery evaporator suitable for high-hydrogen-content flue gas according to claim 1, characterized in that: The steam-water separation device is a perforated plate separator.

6. A waste heat recovery evaporator suitable for high-hydrogen-content flue gas according to claim 1, characterized in that: The bottom of the flue gas channel cylinder is provided with a water outlet and two bottom drain outlets communicating with its inner cavity. The two bottom drain outlets are symmetrically arranged with the water outlet as the axis of symmetry.

7. A waste heat recovery evaporator suitable for high-hydrogen-content flue gas according to claim 1, characterized in that: The outer wall of the flue gas channel cylinder is equipped with a low liquid level alarm switch group, a high liquid level alarm switch group, a magnetic float liquid level gauge group, and a liquid level transmitter group, which are arranged sequentially from left to right.

8. A waste heat recovery evaporator suitable for high-hydrogen-content flue gas according to claim 7, characterized in that: The outer wall of the flue gas channel cylinder is provided with an outer wall drain port and a chemical dosing port. The outer wall drain port is located to the left of the low liquid level alarm switch group, and the chemical dosing port is located to the right of the liquid level transmitter group.

9. A waste heat recovery evaporator suitable for high-hydrogen-content flue gas according to claim 1, characterized in that: The top of the flue gas passage cylinder is provided with a safety valve interface and a vent, and the vent communicates with the inner cavity of the flue gas passage cylinder.

10. A waste heat recovery evaporator suitable for high-hydrogen-content flue gas according to claim 1, characterized in that: The bottom of the flue gas passage cylinder and the economizer body are respectively provided with support bases.

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