Waste heat recovery system for high pressure coal gasification unit

Abstract

The invention discloses a waste heat recovery system of a high-pressure coal gasification device, comprising: a superheater, an economizer, a steam drum, a front fire tube evaporator and a rear fire tube evaporator, the front fire tube evaporator cylinder is arranged on the top of the superheater cylinder, a synthesis gas inlet smoke chamber is arranged on the top of the front fire tube evaporator cylinder, the rear evaporator smoke inlet pipe is connected to the superheater cylinder smoke outlet, and the rear evaporator smoke outlet pipe is connected to the economizer inlet smoke chamber of the fire tube economizer. The advantages of the invention are: the heat of the high-temperature and high-pressure synthesis gas generated by the high-pressure coal gasification device is fully recovered and utilized, gas leakage can be effectively avoided, and the safety is higher.

Description

Technical Field

[0001] The invention relates to the technical field of waste heat recovery, and in particular to a waste heat recovery system of a high-pressure coal gasification device. Background Art

[0002] The high-temperature and high-pressure synthesis gas produced in the high-pressure coal gasification furnace contains 26% hydrogen and a large amount of dust.

[0003] How to maximize the utilization and recovery of waste heat from high-temperature and high-pressure synthesis gas produced by high-pressure coal gasifiers is crucial to the production of high-pressure coal gasifiers. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a waste heat recovery system for a high-pressure coal gasification device, which can fully utilize the heat of high-temperature and high-pressure synthesis gas and has high safety.

[0005] In order to solve the above problems, the technical solution adopted by the present invention is: a waste heat recovery system of a high-pressure coal gasification device, including: an evaporator, a superheater, an economizer, and a steam drum, the evaporator includes a front fire tube evaporator and a rear fire tube evaporator, the superheater includes a vertically arranged steel circular superheater cylinder, a superheater heat exchange tube bundle is arranged in the superheater cylinder, the front fire tube evaporator includes a steel circular front fire tube evaporator cylinder, a front fire tube evaporator heat exchange tube bundle is arranged in the front fire tube evaporator cylinder, The front fire tube evaporator cylinder is arranged on the top of the superheater cylinder, and a synthesis gas inlet smoke chamber is arranged on the top of the front fire tube evaporator cylinder. The upper and lower ends of the front fire tube evaporator heat exchange tube bundle are respectively connected with the synthesis gas inlet smoke chamber and the superheater cylinder, and the lower end of the superheater cylinder is provided with a superheater cylinder smoke outlet. The rear fire tube evaporator comprises: a steel circular rear fire tube evaporator cylinder arranged upright, a rear fire tube evaporator heat exchange tube bundle is arranged in the rear fire tube evaporator cylinder, and the rear fire tube evaporator A top smoke chamber and a bottom smoke chamber are formed in the cylinder of the rear-mounted fire tube evaporator at the upper and lower ends of the heat exchange tube bundle of the evaporator, respectively. A top range partition is provided in the top smoke chamber, and a bottom range partition is provided in the bottom smoke chamber. The bottom range partition divides the bottom smoke chamber into a first smoke chamber and a third smoke chamber that are separated from each other, and the top range partition divides the top smoke chamber into a second smoke chamber and a fourth smoke chamber that are separated from each other. The first smoke chamber is connected to the second smoke chamber through the heat exchange tube bundle of the rear-mounted fire tube evaporator, and the second smoke chamber is connected to the rear-mounted fire tube evaporator through the rear-mounted fire tube evaporator. The heat exchange tube bundle is connected to the third smoke chamber, and the third smoke chamber is connected to the fourth smoke chamber through the rear fire tube evaporator heat exchange tube bundle; a rear evaporator flue gas inlet pipe is provided on the rear fire tube evaporator cylinder at the first smoke chamber position, and a rear evaporator flue gas outlet pipe is provided on the rear fire tube evaporator cylinder at the fourth smoke chamber position; the economizer is a fire tube economizer; the rear evaporator flue gas inlet pipe is connected to the superheater cylinder flue gas outlet, and the rear evaporator flue gas outlet pipe is connected to the economizer inlet smoke chamber of the fire tube economizer.

[0006] Furthermore, the waste heat recovery system of the aforementioned high-pressure coal gasification device, wherein, further includes an air-to-air heat exchanger, the air-to-air heat exchanger including an air-to-air heat exchanger cylinder, an air-to-air heat exchange tube bundle being arranged in the air-to-air heat exchanger cylinder, an air-to-air heat exchanger inlet smoke chamber and an air-to-air heat exchanger outlet smoke chamber being formed in the air-to-air heat exchanger cylinder at the upper and lower ends of the air-to-air heat exchange tube bundle, respectively, the upper and lower ends of the air-to-air heat exchange tube bundle are connected to the air-to-air heat exchanger inlet smoke chamber and the air-to-air heat exchanger outlet smoke chamber, respectively; a cooling gas inlet pipe and a cooling gas outlet pipe are arranged on the air-to-air heat exchanger cylinder, and the economizer outlet smoke chamber is connected to the air-to-air heat exchanger inlet smoke chamber.

[0007] Furthermore, in the waste heat recovery system of the aforementioned high-pressure coal gasification device, the boiler feed water pipe is connected to the water inlet of the fire tube economizer, the water outlet of the fire tube economizer is connected to the steam drum through a pipeline, the front fire tube evaporator cylinder is connected to the steam drum through a first riser and a first downcomer, the rear fire tube evaporator cylinder is connected to the steam drum through a second riser and a second downcomer, the saturated steam outlet on the steam drum is connected to the superheater steam inlet through a saturated steam pipe, and the superheater steam outlet outputs superheated steam.

[0008] Furthermore, in the waste heat recovery system of the aforementioned high-pressure coal gasification device, the front fire tube evaporator cylinder and the front fire tube evaporator heat exchange tube bundle therein are inclined relative to the superheater cylinder, and the first riser is connected to the relatively raised side of the upper end of the inclined front fire tube evaporator cylinder.

[0009] Furthermore, in the waste heat recovery system of the aforementioned high-pressure coal gasification device, the superheater heat exchange tube bundle in the superheater cylinder adopts a horizontally arranged serpentine tube bundle, and the connection structure between the superheater heat exchange tube passing through the superheater cylinder and the superheater cylinder includes: a reinforcement tube is arranged on the superheater heat exchange tube outside the superheater cylinder, one end of the reinforcement tube is welded and sealed to the superheater cylinder, and the other end of the reinforcement tube is welded and sealed to the superheater heat exchange tube.

[0010] Furthermore, in the waste heat recovery system of the aforementioned high-pressure coal gasification device, each superheater heat exchange tube in the first row of the horizontally arranged superheater heat exchange tube bundle located on the windward side is provided with an anti-scouring and anti-wear tile.

[0011] Furthermore, in the waste heat recovery system of the high-pressure coal gasification device, the upper tube sheet and the lower tube sheet of the front-fire tube evaporator heat exchange tube bundle and the upper tube sheet and the lower tube sheet of the rear-fire tube evaporator heat exchange tube bundle all adopt a flexible tube sheet structure; the structure of the upper tube sheet of the front-fire tube evaporator heat exchange tube bundle and the rear-fire tube evaporator heat exchange tube bundle includes an upper tube sheet body, the outer end of the upper tube sheet body is bent toward the outer side of the upper tube sheet body to form an upper tube sheet connecting part, and the inner wall of the evaporator cylinder above the upper tube sheet connecting part is provided with a flexible tube sheet structure toward the evaporator heat exchange tube bundle. The upper end connection part of the hook type is bent, and the upper tube plate connection part is welded and sealed with the upper end connection part of the hook type, and a U-shaped upper transition groove is formed between the upper end connection part of the hook type, the upper tube plate connection part, and the inner wall of the cylinder of the fire tube evaporator; one end of the riser connected to the cylinder of the fire tube evaporator is connected to the cylinder of the fire tube evaporator at an angle upward relative to the cylinder of the fire tube evaporator, and is located outside the corresponding position area of ​​the upper transition groove; the cylinder of the fire tube evaporator is also connected with a steam exhaust pipe, and one end of the steam exhaust pipe is connected to the top of the upper transition groove; The structure of the lower tube sheet of the front fire tube evaporator heat exchange tube bundle and the rear fire tube evaporator heat exchange tube bundle includes a lower tube sheet body, the outer end of the lower tube sheet body is bent toward the outer side of the lower tube sheet body to form a lower tube sheet connection part, and a hook-shaped lower end connection part bent toward the direction of the evaporator heat exchange tube bundle is provided on the inner wall of the evaporator cylinder below the lower tube sheet connection part. The lower tube sheet connection part and the hook-shaped lower end connection part are welded and sealed to fix, and a U-shaped lower transition groove is formed between the hook-shaped lower end connection part, the lower tube sheet connection part, and the inner wall of the fire tube evaporator cylinder; the downcomer is connected to the fire tube evaporator cylinder and is located outside the corresponding position area of ​​the lower transition groove. The fire tube evaporator cylinder is also connected to a lower discharge pipe, and the lower discharge pipe is connected to the bottom end of the lower transition groove.

[0012] Furthermore, in the waste heat recovery system of the aforementioned high-pressure coal gasification device, the gas flow rate in the post-fire tube evaporator is controlled at 10m / s to 15m / s.

[0013] Furthermore, in the waste heat recovery system of the aforementioned high-pressure coal gasification device, the post-evaporator flue gas inlet pipe is a three-way pipe, which includes a vertical pipe body on which a horizontal pipe is arranged, and the superheater cylinder flue gas outlet is connected to the horizontal pipe through a horizontally arranged connecting pipe.

[0014] The advantages of the present invention are: 1. It fully recycles and utilizes the heat of the high-temperature and high-pressure synthesis gas generated by the high-pressure coal gasification device. 2. The superheater cylinder, the front evaporator cylinder, and the rear evaporator cylinder all adopt a steel circular cylinder structure, which can effectively ensure the sealing of the cylinder and prevent gas leakage, thereby ensuring that the entire waste heat recovery system can work safely and stably. 3. The rear fire tube evaporator adopts a three-pass structure, which greatly increases the path of flue gas heat exchange, thereby effectively improving the heat exchange effect. The three-pass structure can effectively save the volume of the equipment, thereby saving the floor space of the entire heat recovery system, and can effectively reduce the amount of steel used. 4. The upper tube sheet of the heat exchange tube bundle of the front fire tube evaporator adopts a flexible tube sheet, which can greatly improve the pressure resistance of the upper tube sheet. The transition groove is set to provide enough buffer space for steam. The first riser is set upwardly with respect to the front fire tube evaporator cylinder, which can better discharge steam. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the layout structure of the waste heat recovery system of the high-pressure coal gasification device described in the present invention.

[0016] Figure 2 It is a schematic diagram of the layout structure of the superheater heat exchange tube bundle in the superheater.

[0017] Figure 3 yes Figure 2 Schematic diagram of the enlarged structure of part A.

[0018] Figure 4 yes Figure 1 Schematic diagram of the structure of the upper tube plate in the front fire tube evaporator and the rear fire tube evaporator.

[0019] Figure 5 yes Figure 1 Schematic diagram of the structure of the lower tube plate in the front fire tube evaporator and the rear fire tube evaporator. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0021] like Figure 1 , Figure 2 , Figure 3 As shown, the waste heat recovery system of the high-pressure coal gasification device includes: an evaporator, a superheater 1, an economizer 2, and a steam drum 3. The evaporator includes a front fire tube evaporator 4 and a rear fire tube evaporator 5. The economizer 2 is a fire tube economizer.

[0022] The superheater 1 comprises: a superheater cylinder 11, which is an upright steel circular cylinder, and a superheater heat exchange tube bundle 12 is arranged in the superheater cylinder 11. A superheater cylinder smoke outlet 101 is arranged at the lower end of the superheater cylinder 11.

[0023] In this embodiment, the superheater heat exchange tube bundle 12 in the superheater cylinder 11 adopts a horizontally arranged serpentine tube bundle, and the connection structure between the superheater heat exchange tube 121 passing through the superheater cylinder 11 and the superheater cylinder 11 includes: a reinforcing tube 122 is arranged on the superheater heat exchange tube 121 outside the superheater cylinder 11, one end of the reinforcing tube 122 is welded and sealed to the outer wall of the superheater cylinder 11, and the other end of the reinforcing tube 122 is welded and sealed to the superheater heat exchange tube 121. The arrangement of the reinforcing tube 122 greatly improves the strength of the tube penetration position and can effectively prevent gas leakage. The horizontally arranged superheater heat exchange tube bundle 12 is located on each superheater heat exchange tube 121 in the first row on the windward side, and an anti-scouring anti-wear tile 123 is arranged. The arrangement of the anti-wear tile 123 can effectively protect the superheater heat exchange tube bundle 12 and extend the service life of the superheater heat exchange tube bundle 12.

[0024] The front fire tube evaporator 4 comprises a front fire tube evaporator cylinder 41, which is a steel round cylinder. A front fire tube evaporator heat exchange tube bundle 42 is arranged in the front fire tube evaporator cylinder 41, and the front fire tube evaporator cylinder 42 is arranged on the top of the superheater cylinder 11. A synthesis gas inlet smoke chamber 43 is arranged on the top of the front fire tube evaporator cylinder 41, and the upper and lower ends of the front fire tube evaporator heat exchange tube bundle 42 are respectively connected to the synthesis gas inlet smoke chamber 43 and the superheater cylinder 11.

[0025] The rear fire tube evaporator 5 comprises: a rear fire tube evaporator cylinder 51 arranged upright, and the rear fire tube evaporator cylinder 51 is a steel round cylinder. A rear fire tube evaporator heat exchange tube bundle 52 is arranged in the rear fire tube evaporator cylinder 51, and a top smoke chamber 53 and a bottom smoke chamber 54 are formed in the rear fire tube evaporator cylinder 51 at the upper and lower ends of the rear fire tube evaporator heat exchange tube bundle 52, respectively. A top section partition 56 is arranged in the top smoke chamber 53, and a bottom section partition 55 is arranged in the bottom smoke chamber 54. The bottom section partition 55 divides the bottom smoke chamber 54 into a first smoke chamber 541 and a third smoke chamber 542 that are isolated from each other, and the top section partition 56 divides the top smoke chamber 53 into a second smoke chamber 531 and a fourth smoke chamber 532 that are isolated from each other. The first smoke chamber 541 is connected to the second smoke chamber 531 through the rear fire tube evaporator heat exchange tube bundle 52, the second smoke chamber 531 is connected to the third smoke chamber 542 through the rear fire tube evaporator heat exchange tube bundle 52, and the third smoke chamber 542 is connected to the fourth smoke chamber 532 through the rear fire tube evaporator heat exchange tube bundle 52. A rear evaporator flue gas inlet pipe 57 is provided on the rear fire tube evaporator cylinder 51 at the position of the first smoke chamber 541, and a rear evaporator flue gas outlet pipe 58 is provided on the rear fire tube evaporator cylinder 51 at the position of the fourth smoke chamber 532. The rear evaporator flue gas inlet pipe 57 is connected to the superheater cylinder flue gas outlet 101, and the rear evaporator flue gas outlet pipe 58 is connected to the economizer inlet smoke chamber 21 of the economizer 2. The rear fire tube evaporator 5 adopts a three-pass structure, which greatly extends the heat exchange path of the high-temperature flue gas, thereby effectively improving the heat exchange effect. The three-pass structure can effectively save the volume and steel consumption of the rear fire tube evaporator 5, thereby greatly saving the overall equipment cost of the heat recovery system.

[0026] The flow rate of the high-temperature flue gas in the post-fire tube evaporator 5 is controlled at 10m / s to 15m / s. The high-temperature flue gas moves vertically up and down in the post-fire tube evaporator 5 and maintains a high flow rate, so that the dust in the gas will be taken away by the flue gas, and will not form dust accumulation in the post-fire tube evaporator heat exchange tube bundle 52. At this flow rate, the post-fire tube evaporator 5 forms a self-cleaning mode.

[0027] In addition, the post-evaporator smoke inlet pipe 57 is a three-way pipe, which includes a vertical pipe body 571, on which a horizontal pipe 572 is arranged, and the superheater cylinder smoke outlet 101 is connected to the horizontal pipe 572 through a horizontally arranged connecting pipe. The three-way pipe is adopted, so that the high-temperature smoke output from the superheater 1 can be turned at the post-evaporator smoke inlet pipe 57 of the three-way pipe structure, and the post-evaporator smoke inlet pipe 57 of the three-way pipe structure provides sufficient space for the high-temperature smoke to turn and rectify.

[0028] In order to further cool the flue gas, this embodiment further includes an air-to-air heat exchanger 6, which includes an air-to-air heat exchanger cylinder 61, in which an air-to-air heat exchange tube bundle 62 is arranged, and an air-to-air heat exchanger inlet smoke chamber 63 and an air-to-air heat exchanger outlet smoke chamber 64 are respectively formed in the air-to-air heat exchanger cylinder 61 at the upper and lower ends of the air-to-air heat exchange tube bundle 62, and the upper and lower ends of the air-to-air heat exchange tube bundle 62 are respectively connected to the air-to-air heat exchanger inlet smoke chamber 63 and the air-to-air heat exchanger outlet smoke chamber 64. A cooling gas input pipe 65 and a cooling gas output pipe 66 are arranged on the air-to-air heat exchanger cylinder 61, and the economizer outlet smoke chamber 22 is connected to the air-to-air heat exchanger inlet smoke chamber 63.

[0029] The boiler feed water pipe 10 is connected to the fire tube economizer water inlet 201, the fire tube economizer water outlet 202 is connected to the steam drum 3 through a pipeline, the front fire tube evaporator cylinder 41 is connected to the steam drum 3 through the first riser 44 and the first downcomer 45, the rear fire tube evaporator cylinder 51 is connected to the steam drum 3 through the second riser 59 and the second downcomer 60, the saturated steam outlet 31 on the steam drum 3 is connected to the superheater steam inlet 13 through the saturated steam pipe 32, and the superheater steam outlet 14 outputs superheated steam.

[0030] In this embodiment, the front fire tube evaporator cylinder 41 and the front fire tube evaporator heat exchange tube bundle 42 therein are The first riser 44 is connected to the relatively raised side of the upper end of the inclined front fire tube evaporator cylinder 41. The front fire tube evaporator cylinder 41 and the front fire tube evaporator heat exchange tube bundle 42 are inclined relative to the superheater cylinder 11, which makes the upper tube sheet of the front fire tube evaporator heat exchange tube bundle 42 inclined. Such a structure can prevent the steam generated in the front fire tube evaporator cylinder 41 from accumulating at the bottom of the upper tube sheet.

[0031] In this embodiment, the upper tube sheet and the lower tube sheet of the front fire tube evaporator heat exchange tube bundle 42 and the upper tube sheet and the lower tube sheet of the rear fire tube evaporator heat exchange tube bundle 52 all adopt a flexible tube sheet structure. Figure 4 As shown, the structure of the upper tube sheet 7 of the front fire tube evaporator heat exchange tube bundle 42 and the rear fire tube evaporator heat exchange tube bundle 52 includes an upper tube sheet body 71, the outer end of the upper tube sheet body 71 is bent toward the outer side of the upper tube sheet body 71 to form an upper tube sheet connecting portion 711, and a hook-shaped upper end connecting portion 712 bent toward the evaporator heat exchange tube bundle is provided on the inner wall of the evaporator cylinder above the upper tube sheet connecting portion 711. The upper tube sheet connecting portion 711 is welded and sealed to the hook-shaped upper end connecting portion 712, and a U-shaped upper transition groove 70 is formed between the hook-shaped upper end connecting portion 712, the upper tube sheet connecting portion 711, and the inner wall of the fire tube evaporator cylinder.

[0032] One end of the riser (first riser 44, second riser 59) connected to the fire tube evaporator cylinder (front fire tube evaporator cylinder 41, rear fire tube evaporator cylinder 51) is connected to the fire tube evaporator cylinder at an angle upward relative to the fire tube evaporator cylinder and is located outside the corresponding position area of ​​the upper transition groove 70. A steam exhaust pipe 713 is also connected to the fire tube evaporator cylinder, and one end of the steam exhaust pipe 713 is connected to the top of the upper transition groove 70.

[0033] The upper tube sheet 7 of the front fire tube evaporator heat exchange tube bundle 42 and the rear fire tube evaporator heat exchange tube bundle 52 adopts a flexible tube sheet structure, and the pressure resistance of the upper tube sheet 7 is greatly enhanced. The setting of the upper transition groove 70 provides a buffer space for steam, thereby preventing the upper tube sheet 7 from being damaged due to excessive pressure, greatly improving the safety of the waste heat recovery system. The purpose of setting the steam exhaust pipe 713 is that once the pressure in the upper transition groove 70 is too high, a part of the steam can be discharged through the steam exhaust pipe 713, which can further prevent the upper tube sheet 7 from being damaged due to excessive pressure.

[0034] like Figure 5 As shown, the structure of the lower tube sheet 8 of the front fire tube evaporator heat exchange tube bundle 42 and the rear fire tube evaporator heat exchange tube bundle 52 includes a lower tube sheet body 81, the outer end of the lower tube sheet body 81 is bent toward the outer side of the lower tube sheet body 81 to form a lower tube sheet connecting portion 811, and a hook-shaped lower end connecting portion 812 bent toward the direction of the evaporator heat exchange tube bundle is provided on the inner wall of the evaporator cylinder below the lower tube sheet connecting portion 811. The lower tube sheet connecting portion 811 is welded and sealed to the hook-shaped lower end connecting portion 812, and a U-shaped lower transition groove 80 is formed between the hook-shaped lower end connecting portion 812, the lower tube sheet connecting portion 811, and the inner wall of the fire tube evaporator cylinder.

[0035] The downcomers (first downcomer 45, second downcomer 60) are connected to the front fire tube evaporator cylinder 41 and the rear fire tube evaporator cylinder 51 of the fire tube evaporator, and are located outside the corresponding position area of ​​the lower transition groove 80. The fire tube evaporator cylinder is also connected to a lower discharge pipe 813, which is connected to the bottom end of the lower transition groove 80. The lower tube sheet 8 of the front fire tube evaporator heat exchange tube bundle 42 and the rear fire tube evaporator heat exchange tube bundle 52 with the above structure has greatly enhanced pressure resistance. The arrangement of the lower discharge pipe 813 is conducive to the discharge of impurities at the bottom.

[0036] In addition, in order to prevent hydrogen embrittlement, in this embodiment, the superheater cylinder 11, the superheater heat exchange tube bundle 12, the front fire tube evaporator cylinder 41, the front fire tube evaporator heat exchange tube bundle 42, the rear fire tube evaporator cylinder 5, and the rear fire tube evaporator heat exchange tube bundle 52 are all made of CrMo steel.

[0037] Flue gas flow: The high-temperature and high-pressure synthesis gas generated by the high-pressure coal gasification furnace enters the synthesis gas inlet smoke chamber 43 The pre-fire tube evaporator heat exchange tube bundle 42 of the pre-fire tube evaporator 4 is cooled, and the high-temperature flue gas in the pre-fire tube evaporator heat exchange tube bundle 42 enters the superheater cylinder 1, and the high-temperature flue gas in the superheater cylinder exchanges heat with the superheater heat exchange tube bundle 12, and then enters the first smoke chamber 541 from the superheater cylinder smoke outlet 101 through the post-evaporator smoke inlet pipe 57, and the high-temperature flue gas in the first smoke chamber 541 enters the second smoke chamber 531 through the post-fire tube evaporator heat exchange tube bundle 52, and the high-temperature flue gas in the second smoke chamber 531 enters the third smoke chamber 542 through the post-fire tube evaporator heat exchange tube bundle 52, and the high-temperature flue gas in the third smoke chamber 542 enters the fourth smoke chamber 532 through the post-fire tube evaporator heat exchange tube bundle 52. The flue gas in the fourth smoke chamber 532 enters the economizer 2 through the post-evaporator smoke outlet pipe 58, and the smoke from the economizer 2 enters the air-to-air heat exchanger 6 for further cooling. The cooled smoke in the air-to-air heat exchanger 6 is discharged through the air-to-air heat exchanger outlet smoke chamber 64.

[0038] Water flow: The boiler feed water pipe 10 enters the drum 2 through the fire tube economizer water inlet 201, and then enters the drum 3 through the fire tube economizer water outlet 202 and the pipeline. The hot water in the drum 3 enters the front fire tube evaporator drum 41 and the rear fire tube evaporator drum 51 through the first downcomer 45 and the second downcomer 60 respectively. The steam-water mixture in the front fire tube evaporator drum 41 enters the drum 3 through the first riser 44, and the steam-water mixture in the rear fire tube evaporator drum 51 enters the drum 3 through the second riser 59. The saturated steam in the drum 3 enters the superheater heat exchange tube bundle 12 through the saturated steam outlet 31 and the steam pipe 32 through the superheater steam inlet 13, and the superheated steam in the superheater heat exchange tube bundle 12 is output through the superheater steam outlet 14.

[0039] The waste heat recovery system of the high-pressure coal gasification device described in the present invention has the following advantages: 1. It can fully recover and utilize the heat of the high-temperature and high-pressure synthesis gas generated by the high-pressure coal gasification device. 2. The superheater cylinder, the front evaporator cylinder, and the rear evaporator cylinder all adopt a steel circular cylinder structure, which can effectively ensure the sealing of the cylinder and prevent gas leakage, thereby ensuring that the entire waste heat recovery system can work safely and stably. 3. The rear fire tube evaporator adopts a three-pass structure, which greatly increases the path of flue gas heat exchange, thereby effectively improving the heat exchange effect. The three-pass structure can effectively save the volume of the equipment, thereby saving the floor space of the entire heat recovery system, and can effectively reduce the amount of steel used. 4. The upper tube sheet of the heat exchange tube bundle of the front fire tube evaporator adopts a flexible tube sheet, which can greatly improve the pressure resistance of the upper tube sheet. The setting of the transition groove provides enough buffer space for steam. The first riser is inclined upward relative to the front fire tube evaporator cylinder, which can better discharge steam.

Claims

1. Waste heat recovery system of high pressure coal gasification unit, including: Evaporator, superheater, economizer, steam drum, characterized in that: the evaporator includes a front fire tube evaporator and a rear fire tube evaporator, the superheater includes a vertically arranged steel round superheater cylinder, the superheater cylinder is provided with a superheater heat exchange tube bundle, the front fire tube evaporator includes a steel round front fire tube evaporator cylinder, the front fire tube evaporator cylinder is provided with a front fire tube evaporator heat exchange tube bundle, the front fire tube evaporator cylinder is arranged on the top of the superheater cylinder, the front fire tube The top of the tube evaporator cylinder is provided with a synthesis gas inlet smoke chamber, the upper and lower ends of the front fire tube evaporator heat exchange tube bundle are respectively connected with the synthesis gas inlet smoke chamber and the superheater cylinder, and the lower end of the superheater cylinder is provided with a superheater cylinder smoke outlet, and the rear fire tube evaporator comprises: a steel round rear fire tube evaporator cylinder arranged upright, a rear fire tube evaporator heat exchange tube bundle is arranged in the rear fire tube evaporator cylinder, and the rear fire tube evaporator heat exchange tube bundle at the upper and lower ends of the rear fire tube evaporator heat exchange tube bundle is connected with the rear fire tube evaporator heat exchange tube bundle. A top smoke chamber and a bottom smoke chamber are respectively formed in the cylinder of the evaporator, a top range partition is arranged in the top smoke chamber, a bottom range partition is arranged in the bottom smoke chamber, the bottom range partition divides the bottom smoke chamber into a first smoke chamber and a third smoke chamber isolated from each other, and the top range partition divides the top smoke chamber into a second smoke chamber and a fourth smoke chamber isolated from each other, the first smoke chamber is connected with the second smoke chamber through a rear fire tube evaporator heat exchange tube bundle, the second smoke chamber is connected with the third smoke chamber through a rear fire tube evaporator heat exchange tube bundle, and the third smoke chamber is connected with the fourth smoke chamber through a rear fire tube evaporator heat exchange tube bundle; a rear evaporator flue gas inlet pipe is arranged on the cylinder of the rear fire tube evaporator at the position of the first smoke chamber, and a rear evaporator flue gas outlet pipe is arranged on the cylinder of the rear fire tube evaporator at the position of the fourth smoke chamber; the economizer is a fire tube economizer; the rear evaporator flue gas inlet pipe is connected with the superheater cylinder flue gas outlet, and the rear evaporator flue gas outlet pipe is connected with the economizer inlet smoke chamber of the fire tube economizer.

2. The waste heat recovery system of the high-pressure coal gasification device according to claim 1, characterized in that: It also includes an air-to-air heat exchanger, which includes an air-to-air heat exchanger cylinder, in which an air-to-air heat exchange tube bundle is arranged, and an air-to-air heat exchanger inlet smoke chamber and an air-to-air heat exchanger outlet smoke chamber are respectively formed in the air-to-air heat exchanger cylinder at the upper and lower ends of the air-to-air heat exchange tube bundle, and the upper and lower ends of the air-to-air heat exchange tube bundle are respectively connected with the air-to-air heat exchanger inlet smoke chamber and the air-to-air heat exchanger outlet smoke chamber; a cooling gas input pipe and a cooling gas output pipe are arranged on the air-to-air heat exchanger cylinder, and the economizer outlet smoke chamber is connected with the air-to-air heat exchanger inlet smoke chamber.

3. The waste heat recovery system of the high-pressure coal gasification device according to claim 1, characterized in that: The boiler feed water pipe is connected to the water inlet of the fire tube economizer, the water outlet of the fire tube economizer is connected to the steam drum through a pipeline, the front fire tube evaporator cylinder is connected to the steam drum through a first riser and a first downcomer, the rear fire tube evaporator cylinder is connected to the steam drum through a second riser and a second downcomer, the saturated steam outlet on the steam drum is connected to the superheater steam inlet through a saturated steam pipe, and the superheater steam outlet outputs superheated steam.

4. The waste heat recovery system of the high-pressure coal gasification device according to claim 4 is characterized in that: The front fire tube evaporator cylinder and the front fire tube evaporator heat exchange tube bundle therein are arranged tilted relative to the superheater cylinder, and the first riser is connected to the relatively raised side of the upper end of the tilted front fire tube evaporator cylinder.

5. The waste heat recovery system of the high-pressure coal gasification device according to claim 4, characterized in that: The superheater heat exchange tube bundle in the superheater cylinder adopts a horizontally arranged serpentine tube bundle, and the connection structure between the superheater heat exchange tube passing through the superheater cylinder and the superheater cylinder includes: a reinforcement tube is arranged on the superheater heat exchange tube outside the superheater cylinder, one end of the reinforcement tube is welded and sealed to the superheater cylinder, and the other end of the reinforcement tube is welded and sealed to the superheater heat exchange tube.

6. The waste heat recovery system of the high-pressure coal gasification device according to claim 5, characterized in that: Each superheater heat exchange tube in the first row of the horizontally arranged superheater heat exchange tube bundle located on the windward side is provided with an anti-scouring and anti-wear tile.

7. The waste heat recovery system of the high-pressure coal gasification device according to claim 4, characterized in that: The upper tube sheet and lower tube sheet of the heat exchange tube bundle of the front fire tube evaporator and the upper tube sheet and lower tube sheet of the heat exchange tube bundle of the rear fire tube evaporator all adopt a flexible tube sheet structure; the structure of the upper tube sheet of the heat exchange tube bundle of the front fire tube evaporator and the upper tube sheet of the heat exchange tube bundle of the rear fire tube evaporator includes an upper tube sheet body, the outer end of the upper tube sheet body is bent toward the outer side of the upper tube sheet body to form an upper tube sheet connecting part, and a hook-shaped upper end connecting part bent toward the direction close to the evaporator heat exchange tube bundle is provided on the inner wall of the evaporator cylinder above the upper tube sheet connecting part. The tube sheet connection part is welded and sealed to the hook-shaped upper end connection part, and a U-shaped upper transition groove is formed between the hook-shaped upper end connection part, the upper tube sheet connection part, and the inner wall of the fire tube evaporator cylinder; one end of the riser connected to the fire tube evaporator cylinder is connected to the fire tube evaporator cylinder at an angle upward relative to the fire tube evaporator cylinder and is located outside the corresponding position area of ​​the upper transition groove; the fire tube evaporator cylinder is also connected to a steam exhaust pipe, and one end of the steam exhaust pipe is connected to the top of the upper transition groove; The structure of the lower tube sheet of the front fire tube evaporator heat exchange tube bundle and the rear fire tube evaporator heat exchange tube bundle includes a lower tube sheet body, the outer end of the lower tube sheet body is bent toward the outer side of the lower tube sheet body to form a lower tube sheet connection part, and a hook-shaped lower end connection part bent toward the direction of the evaporator heat exchange tube bundle is provided on the inner wall of the evaporator cylinder below the lower tube sheet connection part. The lower tube sheet connection part and the hook-shaped lower end connection part are welded and sealed to fix, and a U-shaped lower transition groove is formed between the hook-shaped lower end connection part, the lower tube sheet connection part, and the inner wall of the fire tube evaporator cylinder; the downcomer is connected to the fire tube evaporator cylinder and is located outside the corresponding position area of ​​the lower transition groove. The fire tube evaporator cylinder is also connected to a lower discharge pipe, and the lower discharge pipe is connected to the bottom end of the lower transition groove.

8. The waste heat recovery system of the high-pressure coal gasification device according to claim 1, characterized in that: The gas flow rate in the post-fire tube evaporator is controlled at 10m / s to 15m / s.

9. The waste heat recovery system of the high-pressure coal gasification device according to claim 1, characterized in that: The flue gas inlet pipe of the post-evaporator is a three-way pipe, which includes a vertical pipe body with a horizontal pipe provided on the pipe body. The flue gas outlet of the superheater cylinder is connected to the horizontal pipe through a horizontally arranged connecting pipe.

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