Gas waste heat recoverer equipment in ammonia synthesis

Abstract

The invention discloses gas waste heat recoverer equipment in ammonia synthesis, and relates to the technical field of ammonia synthesis. The device comprises a gas-liquid waste heat recovery device and a gas-gas waste heat recovery device, the gas-liquid waste heat recovery device is arranged on the side of the lower end of the ammonia synthesis tower, an inlet of the gas-liquid waste heat recovery device is connected with an in-tower gas discharge pipe of the ammonia synthesis tower, and an outlet of the gas-liquid waste heat recovery device is connected with an inlet of the gas-gas waste heat recovery device; the gas-liquid waste heat recovery device comprises a first middle air cylinder, an inner heat return water cylinder and an outer heat return water cylinder. The first middle air cylinder is arranged in the center of the interior of the outer heat return water cylinder. By arranging the gas-liquid waste heat recovery device and the gas-gas waste heat recovery device and adopting a two-stage recovery mode, waste heat in high-temperature gas can be recovered step by step, the waste heat is recovered to the maximum extent, the outlet gas emission temperature is reduced, energy is saved, the production cost is reduced, and the energy utilization efficiency is improved; the problem that an existing synthesis ammonia waste heat recovery device is poor in recovery efficiency is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of synthetic ammonia, and in particular relates to a gas waste heat recovery device in ammonia synthesis. Background Art

[0002] Ammonia synthesis tower is a device used to catalyze the reaction of nitrogen and hydrogen under high pressure and high temperature to synthesize ammonia. Ammonia synthesis tower is the heart of ammonia synthesis plant and is a complex reactor. Currently, industrial ammonia synthesis is carried out at a pressure of 15.2-30.4MPa and a temperature of 400-520℃. In order to prevent corrosion of steel by hydrogen under high pressure and high temperature, the ammonia synthesis tower is composed of a high-pressure resistant head, an outer cylinder and high-temperature resistant internal parts installed in the cylinder.

[0003] The outlet gas temperature of the ammonia synthesis tower is 430℃, and the heat in the gas is recovered by the synthesis gas waste heat recovery device to heat the desalted water byproduct steam. Due to the manufacturing material and other factors, the synthesis gas waste heat recovery device in the current synthesis ammonia process has internal leakage and low heat exchange efficiency, and the waste heat recovery of the ammonia synthesis system is incomplete, and the power consumption in the production process is high.

[0004] Therefore, the existing ammonia synthesis waste heat recovery device cannot meet the needs of actual use, so the market is in urgent need of improved technology to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a gas waste heat recovery device in ammonia synthesis. By setting a gas-liquid waste heat recovery device and a gas-gas waste heat recovery device, the waste heat in the high-temperature gas can be recovered step by step in a two-level recovery manner, and the waste heat can be recovered to the maximum extent, so that the outlet gas emission temperature is reduced, energy is saved, production costs are reduced, and energy utilization efficiency is improved, thereby solving the problem of poor recovery efficiency of existing synthetic ammonia waste heat recovery equipment.

[0006] In order to solve the above technical problems, the present invention is achieved through the following technical solutions: The present invention relates to a gas waste heat recovery device in ammonia synthesis, comprising a gas-liquid waste heat recovery device and a gas-to-gas waste heat recovery device. The gas-liquid waste heat recovery device is arranged on the side of the lower end of an ammonia synthesis tower, and its inlet is connected to the gas discharge pipe in the tower of the ammonia synthesis tower, and its outlet is connected to the inlet of the gas-to-gas waste heat recovery device.

[0007] The gas-liquid waste heat recovery device includes a first intermediate gas cylinder, an inner heat-recovery water cylinder and an outer heat-recovery water cylinder; the first intermediate gas cylinder is arranged at the inner center of the outer heat-recovery water cylinder, a first air inlet pipe is arranged on an end surface of one end of the first intermediate gas cylinder, the first air inlet pipe is flange-connected to the gas discharge pipe in the tower, and a first air outlet pipe is arranged on the other end surface of the first intermediate gas cylinder; the inner heat-recovery water cylinder is arranged at the inner center of the first intermediate gas cylinder.

[0008] The gas-to-gas waste heat recovery device includes a second intermediate gas cylinder, a heat recovery gas cylinder and a heat pipe group; the second intermediate gas cylinder is arranged at the inner center of the heat recovery gas cylinder, a second air inlet pipe is arranged on the end surface of one end of the second intermediate gas cylinder, the second air inlet pipe is flange-connected to the first air outlet pipe, and a second air outlet pipe is arranged on the end surface of the other end of the second intermediate gas cylinder; one end of the heat pipe group is inserted into the first intermediate gas cylinder, and the other end is arranged in the heat recovery gas cylinder, and a plurality of heat pipe groups are arranged, which are evenly spaced along the air flow direction, and are used to transfer the heat of the gas in the second intermediate gas cylinder to the gas in the heat recovery gas cylinder.

[0009] Furthermore, a first water inlet pipe and a first water outlet pipe are respectively provided at two ends of the bottom of the inner heat-return water cylinder; and the water flow direction in the inner heat-return water cylinder is opposite to the air flow direction in the first intermediate air cylinder.

[0010] Furthermore, conical portions are provided at both end surfaces of the inner heat recovery water cylinder, and the conical portions are used to divert the gas flowing into the first air inlet pipe.

[0011] Furthermore, the external heat return water cylinder comprises a first upper half cylinder and a first lower half cylinder; first support plates are integrally formed at the edges of the first upper half cylinder and the first lower half cylinder, and the upper and lower first support plates are locked by fasteners; a second water inlet pipe and a second water outlet pipe are respectively provided at both ends of the bottom of the first lower half cylinder, and the water flow direction in the external heat return water cylinder is opposite to the air flow direction in the first intermediate air cylinder; the first lower half cylinder is fixed on the first support platform.

[0012] Furthermore, pipe wrapping parts extend from both ends of the first upper semi-cylinder and the first lower semi-cylinder; the upper and lower pipe wrapping parts wrap the gas pipeline.

[0013] Furthermore, three staggered baffles are arranged inside the second intermediate air cylinder, and two groups of heat pipe groups are arranged in front of each baffle.

[0014] Furthermore, the heat pipe group includes six long heat pipes evenly distributed along the circumference and six short heat pipes evenly distributed along the circumference; the long heat pipes and the short heat pipes are alternately distributed.

[0015] Furthermore, the heat recovery air cylinder includes a second upper half cylinder and a second lower half cylinder; second support plates are integrally formed at the edges of the second upper half cylinder and the second lower half cylinder, and the upper and lower second support plates are locked by fasteners; a third water inlet pipe is arranged on the end surface of the second lower half cylinder, and a third water outlet pipe is arranged on the end surface of the second upper half cylinder, and the air flow direction in the heat recovery air cylinder is opposite to the air flow direction in the second intermediate air cylinder; the second lower half cylinder is fixed on the second support platform.

[0016] The present invention has the following beneficial effects: The present invention provides a gas-liquid waste heat recovery device and a gas-to-gas waste heat recovery device. The outlet gas of the ammonia synthesis tower first passes through the gas-liquid waste heat recovery device to transfer the heat to cold water, and then passes through the gas-to-gas waste heat recovery device to transfer the heat to the cold air. Through the two-level recovery method, the waste heat in the high-temperature gas can be recovered step by step, and the waste heat is recovered to the maximum extent, so that the discharge temperature of the outlet gas is reduced, energy is saved, production costs are reduced, and energy utilization efficiency is improved.

[0017] The present invention provides a first intermediate gas cylinder, an inner heat recovery water cylinder and an outer heat recovery water cylinder. The design of the inner and outer heat recovery water cylinders allows the outlet gas to fill the entire first intermediate gas cylinder, and the first intermediate gas cylinder can fully contact with cold water, so that the waste heat recovery effect is better. The design of the pipeline wrapping part allows the gas-liquid waste heat recovery device to also wrap the conveying pipeline, thereby preventing heat from being transferred to the surrounding environment through the conveying pipeline, causing heat waste. The split design of the outer heat recovery water cylinder makes the entire device easy to install and maintain.

[0018] The present invention provides a second intermediate gas cylinder, a heat recovery gas cylinder and a heat pipe group. The gas in the second intermediate gas cylinder is buffered by a baffle so that it can fully contact the heat pipe group. The heat pipe group is designed to be circular, which makes the contact with the gas more complete. The heat in the gas can be more conveniently transferred to the cold air in the heat recovery gas cylinder, and the waste heat recovery effect is better. The split design of the heat recovery gas cylinder makes the whole device easy to install and maintain. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of the overall structure appearance; Figure 2 It is a cross-sectional view of the overall structure; Figure 3 This is a schematic diagram of the structure of a gas-liquid waste heat recovery device; Figure 4 It is a schematic diagram of the structure of the internal heat recovery water cylinder; Figure 5 This is a schematic diagram of the structure of the external heat return water cylinder; Figure 6 This is a schematic diagram of the structure of the gas-to-gas waste heat recovery device; Figure 7 is a schematic diagram of the internal structure of the second intermediate air cylinder; Figure 8 Schematic diagram of the heat pipe group structure.

[0021] In the accompanying drawings, the components represented by the reference numerals are listed as follows: 1. Gas-liquid waste heat recovery device; 2. Gas-gas waste heat recovery device; 3. Ammonia synthesis tower; 11. First intermediate gas cylinder; 12. Internal heat recovery cylinder; 13. External heat recovery cylinder; 21. Second intermediate gas cylinder; 22. Heat recovery gas cylinder; 23. Heat pipe group; 31. Gas discharge pipe in the tower; 111. First air inlet pipe; 112. First air outlet pipe; 121. First water inlet pipe; 122. First water outlet pipe; 123. Conical part; 131. First upper half cylinder; 132. First Lower half cylinder; 133, first support plate; 134, pipe wrapping part; 135, second water inlet pipe; 136, second water outlet pipe; 137, first support platform; 211, second air inlet pipe; 212, second air outlet pipe; 213, baffle; 221, second upper half cylinder; 222, second lower half cylinder; 223, second support plate; 224, third water inlet pipe; 225, third water outlet pipe; 226, second support platform; 231, long heat pipe; 232, short heat pipe. Implementation

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0023] See also Figures 1-2 As shown, the present invention is a gas waste heat recovery device in ammonia synthesis, including a gas-liquid waste heat recovery device 1 and a gas-to-gas waste heat recovery device 2. The gas-liquid waste heat recovery device 1 is arranged on the side of the lower end of the ammonia synthesis tower 3, and its inlet is connected to the gas discharge pipe 31 in the tower of the ammonia synthesis tower 3, and its outlet is connected to the inlet of the gas-to-gas waste heat recovery device 2.

[0024] The gas in the ammonia synthesis tower 3 is transported to the gas-liquid waste heat recovery device 1 through the gas discharge pipe 31 in the tower, and the heat in the gas is transferred to the cold water through the gas-liquid waste heat recovery device 1, and then transported to the gas-to-gas waste heat recovery device 2, and the heat in the gas is transferred to the cold air through the gas-to-gas waste heat recovery device 2. Through the two-level recovery method, the waste heat in the high-temperature gas can be recovered step by step, and the waste heat is recovered to the maximum extent, so that the outlet gas emission temperature is reduced, energy is saved, production costs are reduced, and energy utilization efficiency is improved.

[0025] Among them Figure 3 As shown, the gas-liquid waste heat recovery device 1 includes a first intermediate gas cylinder 11, an inner heat recovery water cylinder 12 and an outer heat recovery water cylinder 13; the first intermediate gas cylinder 11 is arranged at the inner center of the outer heat recovery water cylinder 13, and a first air inlet pipe 111 is arranged on an end surface of one end of the first intermediate gas cylinder 11, and the first air inlet pipe 111 is flange-connected to the gas discharge pipe 31 in the tower, and a first air outlet pipe 112 is arranged on the other end surface of the first intermediate gas cylinder 11; the inner heat recovery water cylinder 12 is arranged at the inner center of the first intermediate gas cylinder 11.

[0026] Among them Figure 4 As shown, a first water inlet pipe 121 and a first water outlet pipe 122 are respectively provided at both ends of the bottom of the inner return hot water cylinder 12; and the water flow direction in the inner return hot water cylinder 12 is opposite to the air flow direction in the first intermediate air cylinder 11; conical portions 123 are provided at both end surfaces of the inner return hot water cylinder 12, and the conical portions 123 are used to divert the gas flowing into the first air inlet pipe 111.

[0027] The gas near the center of the first intermediate gas cylinder 11 can fully contact the inner heat recovery water cylinder 12, and transfer heat to the cold water in the inner heat recovery water cylinder 12. The design of the conical portion 123 at the end of the inner heat recovery water cylinder 12 can diffuse the gas to the surrounding of the interior of the first intermediate gas cylinder 11 to avoid gas accumulation, while reducing the gas flow rate and improving the heat recovery effect.

[0028] Among them Figure 5 As shown, the external heat return water cylinder 13 comprises a first upper half cylinder 131 and a first lower half cylinder 132; first support plates 133 are integrally formed at the edges of the first upper half cylinder 131 and the first lower half cylinder 132, and the upper and lower first support plates 133 are locked by fasteners; a second water inlet pipe 135 and a second water outlet pipe 136 are respectively provided at the two ends of the bottom of the first lower half cylinder 132, and the water flow direction in the external heat return water cylinder 13 is opposite to the air flow direction in the first intermediate gas cylinder 11; the first lower half cylinder 132 is fixed on the first support platform 137; pipe wrapping parts 134 are extended from both ends of the first upper half cylinder 131 and the first lower half cylinder 132; the upper and lower pipe wrapping parts 134 wrap the gas pipeline inside.

[0029] The design of the inner and outer double heat return water cylinders 12 and 13 enables the first intermediate gas cylinder 11 to be in full contact with the cold water, and the waste heat recovery effect is better. The design of the pipe wrapping part 134 enables the gas-liquid waste heat recovery device 1 to also wrap the conveying pipe, avoiding the heat from being transferred to the surrounding environment through the conveying pipe, causing heat waste. The split design of the outer heat return water cylinder 13 makes the whole device easy to install and maintain.

[0030] Among them Figure 6 As shown, the gas-to-gas waste heat recovery device 2 includes a second intermediate gas cylinder 21, a heat recovery gas cylinder 22 and a heat pipe group 23; the second intermediate gas cylinder 21 is arranged at the inner center of the heat recovery gas cylinder 22, and a second air inlet pipe 211 is arranged on the end surface of one end of the second intermediate gas cylinder 21, the second air inlet pipe 211 is flange-connected with the first air outlet pipe 112, and a second air outlet pipe 212 is arranged on the other end surface of the second intermediate gas cylinder 21; one end of the heat pipe group 23 is inserted into the first intermediate gas cylinder 11, and the other end is arranged in the heat recovery gas cylinder 22. There are multiple groups of heat pipe groups 23, which are evenly distributed along the air flow direction, and are used to transfer the heat of the gas in the second intermediate gas cylinder 21 to the gas in the heat recovery gas cylinder 22.

[0031] Among them Figure 6 As shown, the heat recovery cylinder 22 includes a second upper cylinder 221 and a second lower cylinder 222; the edges of the second upper cylinder 221 and the second lower cylinder 222 are integrally formed with a second support plate 223, and the upper and lower second support plates 223 are locked by fasteners; a third water inlet pipe 224 is arranged on the end surface of the second lower cylinder 222, and a third water outlet pipe 225 is arranged on the end surface of the second upper cylinder 221. The airflow direction in the heat recovery cylinder 22 is opposite to that in the second intermediate cylinder 21; the second lower cylinder 222 is fixed on the second support platform 226. The split design of the heat recovery cylinder 22 makes the entire device easy to install and maintain.

[0032] Among them Figures 7-8 As shown, three staggered baffles 213 are arranged inside the second intermediate air cylinder 21, and two groups of heat pipe groups 23 are arranged in front of each baffle 213; the heat pipe group 23 includes six long heat pipes 231 evenly distributed along the circumference and six short heat pipes 232 evenly distributed along the circumference; the long heat pipes 231 and the short heat pipes 232 are staggered.

[0033] The baffle 213 plays a role in buffering and reducing speed, while allowing the gas to fully contact the heat pipe group 23. The heat pipe group 23 is designed to be circular, and the staggered distribution design of the long heat pipe 231 and the short heat pipe 232 allows the gas in each area of ​​the second intermediate gas cylinder 21 to contact the heat pipe, so that the heat in the gas can be more conveniently transferred to the cold air in the heat recovery gas cylinder 22, and the waste heat recovery effect is better.

[0034] The above are only preferred embodiments of the present invention and do not limit the present invention. Any modification to the technical solutions recorded in the aforementioned embodiments, any equivalent replacement of some of the technical features therein, and any modification, equivalent replacement, and improvement made are all within the protection scope of the present invention.

Claims

1. A gas waste heat recovery device for ammonia synthesis, comprising a gas-liquid waste heat recovery device (1) and a gas-gas waste heat recovery device (2), characterized in that: The gas-liquid waste heat recovery device (1) is arranged at the side of the lower end of the ammonia synthesis tower (3), its inlet is connected to the gas discharge pipe (31) in the ammonia synthesis tower (3), and its outlet is connected to the inlet of the gas-gas waste heat recovery device (2); The gas-liquid waste heat recovery device (1) comprises a first intermediate gas cylinder (11), an inner heat recovery water cylinder (12) and an outer heat recovery water cylinder (13); The first intermediate gas cylinder (11) is arranged at the inner center of the external heat recovery water cylinder (13); a first gas inlet pipe (111) is arranged on an end surface of one end of the first intermediate gas cylinder (11); the first gas inlet pipe (111) is flange-connected to the gas discharge pipe (31) in the tower; and a first gas outlet pipe (112) is arranged on the other end surface of the first intermediate gas cylinder (11); The inner heat recovery cylinder (12) is arranged at the inner center of the first intermediate cylinder (11); The gas-to-gas waste heat recovery device (2) comprises a second intermediate gas cylinder (21), a heat recovery gas cylinder (22) and a heat pipe group (23); The second intermediate air cylinder (21) is arranged at the inner center of the heat recovery air cylinder (22); a second air inlet pipe (211) is arranged on an end surface of one end of the second intermediate air cylinder (21); the second air inlet pipe (211) is flange-connected to the first air outlet pipe (112); and a second air outlet pipe (212) is arranged on the other end surface of the second intermediate air cylinder (21); One end of the heat pipe group (23) is inserted into the first intermediate gas cylinder (11), and the other end is arranged in the heat recovery gas cylinder (22). The heat pipe group (23) is provided with a plurality of groups, which are evenly spaced along the air flow direction and are used to transfer the heat of the gas in the second intermediate gas cylinder (21) to the gas in the heat recovery gas cylinder (22).

2. The device for recovering waste heat from ammonia synthesis according to claim 1, characterized in that: A first water inlet pipe (121) and a first water outlet pipe (122) are respectively provided at two ends of the bottom of the internal heat recovery water cylinder (12); Furthermore, the water flow direction in the inner heat return water cylinder (12) is opposite to the air flow direction in the first intermediate air cylinder (11).

3. The waste heat recovery device for gas in ammonia synthesis according to claim 1, characterized in that: Conical portions (123) are provided at both end surfaces of the internal heat recovery water cylinder (12), and the conical portions (123) are used to divert the gas flowing into the first air inlet pipe (111).

4. The gas waste heat recovery device in ammonia synthesis according to claim 1, characterized in that: The external heat return water cylinder (13) comprises a first upper half cylinder (131) and a first lower half cylinder (132); A first support plate (133) is integrally formed at the edges of the first upper semi-cylinder (131) and the first lower semi-cylinder (132), and the upper and lower first support plates (133) are locked by fasteners; A second water inlet pipe (135) and a second water outlet pipe (136) are respectively provided at two ends of the bottom of the first lower half cylinder (132); the water flow direction in the external heat return cylinder (13) is opposite to the air flow direction in the first intermediate cylinder (11); The first lower half cylinder (132) is fixed on a first support platform (137).

5. The device for recovering waste heat from ammonia synthesis according to claim 4, characterized in that: Both ends of the first upper semi-cylinder (131) and the first lower semi-cylinder (132) are extended with pipe wrapping portions (134); The upper and lower pipe wrapping parts (134) wrap the gas pipe.

6. The waste heat recovery device for gas in ammonia synthesis according to claim 1, characterized in that: Three staggered baffles (213) are arranged inside the second intermediate air cylinder (21), and two groups of heat pipe groups (23) are arranged in front of each baffle (213).

7. The device for recovering waste heat from ammonia synthesis according to claim 6, characterized in that: The heat pipe group (23) comprises six long heat pipes (231) evenly distributed along the circumference and six short heat pipes (232) evenly distributed along the circumference; The long heat pipes (231) and the short heat pipes (232) are distributed in an alternating manner.

8. The device for recovering waste heat from ammonia synthesis according to claim 1, characterized in that: The heat recovery cylinder (22) comprises a second upper semi-cylinder (221) and a second lower semi-cylinder (222); A second support plate (223) is integrally formed at the edges of the second upper semi-cylinder (221) and the second lower semi-cylinder (222), and the upper and lower second support plates (223) are locked by fasteners; A third water inlet pipe (224) is provided on the end surface of the second lower half cylinder (222), a third water outlet pipe (225) is provided on the end surface of the second upper half cylinder (221), and the airflow direction in the heat recovery cylinder (22) is opposite to the airflow direction in the second intermediate cylinder (21); The second lower half cylinder (222) is fixed on a second support platform (226).

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