CN215373564U

CN215373564U - High-temperature flue gas waste heat recovery device

Info

Publication number: CN215373564U
Application number: CN202120224715.0U
Authority: CN
Inventors: 顾磊; 张武玄; 叶勇
Original assignee: Shanghai Boiler Works Co Ltd
Current assignee: Shanghai Boiler Works Co Ltd
Priority date: 2021-01-27
Filing date: 2021-01-27
Publication date: 2021-12-31
Anticipated expiration: 2031-01-27

Abstract

The utility model discloses a high-temperature flue gas waste heat recovery device which comprises a waste heat boiler and at least one steam drum, wherein the waste heat boiler is a vertical pressure container, a circulating steam inlet end of the waste heat boiler and a circulating steam outlet end of the steam drum are connected through a downcomer pipeline, the circulating steam outlet end of the waste heat boiler and the circulating steam inlet end of the steam drum are connected through an ascending pipe pipeline, a water supply inlet end of the steam drum is connected with a water supply pipeline, and a saturated steam outlet end of the steam drum and the saturated steam inlet end of the waste heat boiler are connected through a saturated steam pipeline. The utility model has the following beneficial effects: the horizontal space occupied by the equipment is small, and the waste heat boiler and the superheater are combined in a vertical equipment; the steam drums can be freely and flexibly arranged in each area on the upper part of the waste boiler, and the small area space of the platform is effectively utilized; the spiral coil structure is introduced, so that the heat transfer coefficient is increased, and the heat exchange efficiency is improved; saturated steam and superheated steam can be generated simultaneously, and the energy utilization efficiency is improved; the procurement and manufacturing cost is reduced.

Description

High-temperature flue gas waste heat recovery device

Technical Field

The utility model relates to a high-temperature flue gas waste heat recovery device, and belongs to the technical field of coal chemical industry application.

Background

The temperature of high-temperature flue gas generated by the gasification furnace is between 900 ℃ and 1500 ℃, but the high-temperature flue gas can be used only by being cooled to 200 ℃ to 350 ℃, so that the flue gas has extremely high waste heat recovery value, and if the high-level heat energy can be recycled and used, and water is used for absorbing the heat energy to generate superheated steam for power generation, the energy utilization efficiency can be improved, and the power consumption demand in a plant can be reduced.

The main heat exchange tube structure of the existing waste heat recovery equipment using water to absorb heat mainly takes the form of a horizontal flue and a heat exchange tube or a screen type water-cooled wall, and saturated steam is generated and enters a steam pocket for steam-water separation and then enters an additionally arranged superheater so as to generate superheated steam. The design scheme has the advantages that on one hand, the heat exchange efficiency is not high, the inner diameter or the length of the waste heat recovery equipment needs to be increased, and on the other hand, the occupied area is relatively large.

Disclosure of Invention

The technical problem to be solved by the utility model is as follows: the heat exchange efficiency of the waste heat recovery equipment is improved under the condition that the floor area of the waste heat recovery equipment is not increased.

In order to solve the technical problem, the technical scheme of the utility model is to provide a high-temperature flue gas waste heat recovery device which is characterized by comprising a waste heat boiler and at least one steam drum, wherein the waste heat boiler is a vertical pressure container, a circulating steam inlet end of the waste heat boiler is connected with a circulating steam outlet end of the steam drum through a downcomer pipeline, a circulating steam outlet end of the waste heat boiler is connected with a circulating steam inlet end of the steam drum through an ascending pipe pipeline, a water supply inlet end of the steam drum is connected with a water supply pipeline, and a saturated steam outlet end of the steam drum is connected with a saturated steam inlet end of the waste heat boiler through a saturated steam pipeline.

Preferably, the downcomer pipeline is provided with a circulating pump which enables the flowing direction to be from the steam drum to the waste heat boiler; the water supply pipeline is provided with an adjusting valve.

Preferably, a seventh port for high-temperature flue gas to enter is arranged on the side of the bottom of the waste heat boiler; the waste heat boiler comprises an external equipment barrel, a plurality of sections of waste heat structures distributed up and down are arranged in the external equipment barrel, a port is respectively arranged at the positions at the two ends of each section of waste heat structure on the waste heat boiler, and a port is respectively arranged at the two ends of the waste heat boiler.

Preferably, the port of the waste heat boiler, which is positioned at the lower end of the waste heat structure and is connected with the downcomer pipeline, is a circulating steam inlet end of the waste heat boiler; the port of the waste heat boiler, which is positioned at the upper end of the waste heat structure and is connected with the ascending pipe pipeline, is a circulating steam outlet end of the waste heat boiler; the port of the waste heat boiler, which is positioned at the lower end of one waste heat structure and is connected with the saturated steam pipeline, is a saturated steam inlet end of the waste heat boiler; and a port which is positioned at the upper end of one waste heat structure on the waste heat boiler and is away from the high-temperature flue gas waste heat recovery device is a saturated steam outlet end of the waste heat boiler.

Preferably, each section of waste heat structure in the external equipment cylinder comprises an external screen type water-cooling wall, and the external screen type water-cooling walls of any two adjacent sections of structures are connected through an expansion joint; a gap is arranged between the external screen type water-cooled wall and the external equipment cylinder.

Preferably, each section of waste heat structure in the external equipment cylinder further comprises a spiral coil, and a plurality of layers of spiral coils which are nested and arranged are arranged in the external screen type water-cooled wall; the multilayer spiral coil pipes are communicated with each other, and only one inlet and one outlet are arranged on the multilayer spiral coil pipes and are respectively ports at the upper end and the lower end of the waste heat structure.

Preferably, each layer of the spiral coil is formed by winding a plurality of heat exchange tubes into a cylindrical structure in a spiral manner.

Preferably, the upper and lower adjacent circles of heat exchange tubes of each layer of spiral coil are welded together in a sealing manner through fins.

Preferably, the number of the circulating steam inlet ends of the waste heat boiler, the number of the circulating steam outlet ends of the waste heat boiler and the number of the steam drums are the same.

Preferably, the steam drum is a vertical or horizontal steam drum.

The utility model combines the evaporation section and the overheating section of the waste heat boiler in a cylinder body, and the inside of the cylinder body is divided into three sections. The flue gas flows upwards in the flue gas, and the deposited ash is discharged from the bottom. According to the requirements of an owner, the on-site flue gas conditions and the like, superheated steam with a certain yield meeting the requirements can be generated by designing the lengths of the three sections, even only saturated steam is generated, but the diameter of the cylinder body cannot be greatly changed. The heat exchange structure adopts a structure of the spiral coil and the external screen type water-cooled wall, and the two sides of the spiral coil are washed by smoke gas to form cross flow, so that the heat transfer coefficient can be effectively increased, and the energy utilization efficiency is improved.

Because the silicon carbide refractory material is coated on the inner side of the external screen type water-cooled wall, the superheater section in the three sections of the waste heat boiler is positioned in the middle of the equipment, and the temperature of flue gas is reduced to a certain extent compared with that of the flue gas at an inlet. Therefore, when the required steam pressure is low and the temperature of the superheated steam is not high, all the heat exchange tubes and the water-cooled wall can be made of low alloy steel such as 15CrMo and the like, and a nickel-based alloy steel tube is not required to be used as the material of the tubes of sections such as a superheater. Thereby saving procurement and manufacturing costs.

In addition, the specification of the steam drum is determined through the design of the steam drum, the vertical steam drums can be adopted when the steam production and the pressure of the steam drum are not large, and the vertical steam drums are dispersedly arranged on the upper part of the waste heat boiler, so that the waste heat boiler is not limited to the same layer of steel frame platform, the field space is effectively utilized, and the occupied area is reduced.

The external steam-water pipeline connects two kinds of equipment, and each group of pipelines adopts a main pipeline + a header + distribution pipes (a plurality of different pipe orifices in quantity and specification are arranged on each equipment, so that the distribution pipes are connected with the pipe orifices on each equipment, each distribution pipe is led out by the header, and then one main pipeline is led out to other pipelines from the header), so that the three-dimensional space occupied by the pipelines and the support is reduced as much as possible. The collecting box can be designed into an arc horizontal type or a vertical type collecting box according to field conditions, and the circulating pump also adopts a vertical pump.

According to the utility model, each waste heat recovery device is transformed into a vertical structure, so that the effect of saving horizontal space is realized, and the utility model has higher engineering application value.

Compared with the prior art, the utility model has the following beneficial effects:

1. the equipment occupies small horizontal space, and the waste heat boiler and the superheater are combined in a vertical equipment, so that the vertical space is effectively utilized, and the occupied area is reduced;

2. the vertical steam drums can be freely and flexibly arranged in each area on the upper part of the waste boiler, so that the small area space of the platform is effectively utilized;

3. the spiral coil structure is introduced, so that the heat transfer coefficient is increased, and the heat exchange efficiency is improved;

4. the superheater heat exchange tube can be made of low-alloy steel materials when the steam temperature is low, so that the purchase and manufacturing cost is reduced;

5. can simultaneously generate saturated steam and superheated steam, and improve the energy utilization efficiency.

Drawings

FIG. 1 is a process flow diagram of a high temperature flue gas waste heat recovery device;

FIG. 2 is a schematic structural diagram of a waste heat boiler;

FIG. 3 is a schematic diagram of the winding pattern of a single layer helical coil;

FIG. 4 is a schematic top view of a multi-layer spiral coil inside a waste heat boiler.

Detailed Description

In order to make the utility model more comprehensible, preferred embodiments are described in detail below with reference to the accompanying drawings.

Example 1

The utility model provides a high-temperature flue gas waste heat recovery device, as shown in figure 1, comprising: the system comprises a waste heat boiler 1, a group of steam drums 2, a group of downcomer pipelines 3 containing a circulating pump 7 and flowing in the direction from the vertical steam drum 2 to the waste heat boiler 1, a group of riser pipelines 4 flowing in the direction from the waste heat boiler 1 to the steam drums 2, a saturated steam pipeline 5 from the top of the steam drums 2 to a high-temperature superheat section 12 in the middle of the waste heat boiler 1, and a water feeding pipeline 6 with an adjusting valve and entering each steam drum 2.

The circulating steam inlet end of the waste heat boiler 1 is connected with the circulating steam outlet end of the steam drum 2 through a downcomer pipeline 3, the circulating steam outlet end of the waste heat boiler 1 is connected with the circulating steam inlet end of the steam drum 2 through an ascending pipe pipeline 4, the water supply inlet end of the steam drum 2 is connected with a water supply pipeline 6, and the saturated steam outlet end of the steam drum 2 is connected with the saturated steam inlet end of the waste heat boiler 1 through a saturated steam pipeline 5.

As shown in fig. 2, the waste heat boiler 1 is a vertical pressure vessel. A seventh port 107 for allowing high-temperature flue gas D to enter is formed in the side of the bottom of the waste heat boiler 1; the exhaust-heat boiler 1 comprises an external equipment barrel 18, three sections of exhaust-heat structures which are distributed up and down are arranged in the external equipment barrel 18, and the three sections of exhaust-heat structures are respectively as follows from bottom to top: a high-temperature radiation section 13, a high-temperature overheating section 12 and a medium-temperature evaporation section 11. The positions of the two ends of each section of waste heat structure on the waste heat boiler 1 are respectively provided with a port, and the two ends of the waste heat boiler 1 are respectively provided with an eighth port 108 and a ninth port 109.

The ports of the waste heat boiler 1, which are positioned at the lower end of the waste heat structure and connected with the downcomer pipeline 3, are the circulating steam inlet ports of the waste heat boiler 1, and are respectively a second port 102 and a sixth port 106; the ports of the waste heat boiler 1, which are positioned at the upper end of the waste heat structure and connected with the ascending pipe 4, are the circulating steam outlet ends of the waste heat boiler 1, and are respectively a first port 101 and a fifth port 105; a port, which is located at the lower end of one waste heat structure and connected with the saturated steam pipeline 5, of the waste heat boiler 1 is a saturated steam inlet end of the waste heat boiler 1, namely a fourth port 104; the port of the waste heat boiler 1, which is located at the upper end of one waste heat structure and leaves the high-temperature flue gas waste heat recovery device, is the saturated steam outlet end of the waste heat boiler 1, i.e. the third port 103.

The waste heat structure of each section is a cylindrical water-cooled wall composed of multiple layers of spiral coils 16, the side of the inner wall of the water-cooled wall facing the high-temperature flue gas is coated with silicon carbide refractory material, as shown in fig. 4, a circle of cylindrical water-cooled wall (namely, an external screen type water-cooled wall 14) is distributed on the outer layer of the water-cooled wall of each section of spiral coils, so that the cylindrical water-cooled wall is separated from the outer wall of the boiler. Flue gas flows through the inner area of the outer screen type water-cooled wall 14, and the two sides of the spiral coil 16 are flushed by the flue gas to form cross flow. A gap is formed between the external screen type water-cooled wall 14 and the external equipment cylinder 18, nitrogen is filled between the cylindrical water-cooled wall (namely the external screen type water-cooled wall 14) and the external equipment cylinder 18 for protection, and an expansion joint 15 is arranged between each section of cylindrical water-cooled wall (namely the external screen type water-cooled wall 14) to absorb thermal expansion displacement. A plurality of layers of spiral coil pipes 16 which are arranged in a nested manner are arranged in the external screen type water-cooled wall 14; the multiple layers of spiral coil pipes 16 are communicated with each other, and each layer of spiral coil pipe 16 is provided with a plurality of inlets and outlets which are respectively connected to the inlet and outlet header tanks at the upper and lower ends of the waste heat structure through the leading-in and leading-out pipes. Therefore, although the waste heat structures are communicated through the header, the water inside the waste heat structures can only pass through one waste heat structure in the flowing process.

As shown in fig. 1, the steam coming out of the saturated steam outlet end of the waste heat boiler 1 is superheated steam C; the water supply pipeline 6 is communicated with the steam drum 2 and provides steam drum water supply A for the steam drum 2; a low-temperature flue gas B is discharged from a ninth port 109 at the top of the waste heat boiler 1; furnace bottom ash E is discharged from an eighth port 108 at the bottom of the waste heat boiler 1; high-temperature flue gas D enters from an inlet at the side of the bottom of the waste heat boiler 1.

In fig. 2, the downward arrows indicate ash flow, the upward arrows indicate flue gas flow, and the horizontal arrows indicate steam flow.

As shown in fig. 3, each layer of spiral coil 16 is formed by spirally winding a certain number of heat exchange tubes into a cylindrical structure, the bottom and the top of the cylindrical structure extend out and are connected to an inlet/outlet header, and two adjacent circles of heat exchange tubes above and below each layer of spiral coil 16 are welded by using fins 17 to play a role in sealing.

The number and the specification of the steam drums 2 are determined according to the steam production of the waste heat boiler 1, and the form of the steam drums 2 can be vertical or horizontal steam drums according to pressure and steam yield. The steam drum 2 internal parts are in the forms of a baffle/cyclone separator and a corrugated plate separator (horizontal steam drum) or a circular truncated cone baffle and a wire mesh separator (vertical steam drum).

The quantity of the circulating steam inlet ends of the waste heat boiler 1, the quantity of the circulating steam outlet ends of the waste heat boiler 1 and the quantity of the steam drums 2 are the same.

The steam drum 2 is provided with an on-site liquid level meter and a balance container, and the water supply quantity of the water supply pipeline 6 to the steam drum 2 is adjusted by using a liquid level signal, so that the liquid level inside the steam drum 2 is balanced. The steam drum 2 is also provided with a safety valve, a remote transmission liquid level meter, a pressure gauge and other instruments.

One end of a downcomer pipeline 3 is connected with the bottom of the steam drum 2, and the downcomer pipeline is combined into a pipe to be downwards connected with an inlet and outlet pipeline of the circulating pump after being collected by a header. In this embodiment, the circulation pump 7 is a vertical centrifugal pump.

The liquid water in the steam drums 2 is led out from a descending pipe opening at the bottom of each steam drum 2 by the descending pipe pipeline 3, converged into a main descending pipe, enters the circulating pump 7 for pressurization, and is redistributed to the lowest-end high-temperature radiation section 13 and the uppermost-end medium-temperature evaporation section 11 of the waste heat boiler 1.

One end of the ascending pipe 4 is connected with the high-temperature radiation section 13 and the medium-temperature evaporation section 11 of the waste heat boiler 1, and the steam-water mixture is led out of the waste heat boiler 1 and distributed to each steam drum 2.

The water supply pipeline 6 is respectively connected with the water supply pipe of the steam pocket 2, the water supply pipeline 6 is provided with an adjusting valve, and the water inflow is adjusted according to the reading of the liquid level meter on the steam pocket 2, so that the water level in the steam pocket 2 is maintained near the normal liquid level line.

Wherein, the flue gas entering the device of the utility model is generated by a gasification furnace through high-temperature catalytic reaction, the temperature is between 900 ℃ and 1500 ℃, and the main gas is H₂、CO、H₂O and part of the sulfur-containing gases and dust.

The water fed into the steam drum of the device is weakly alkaline deoxygenated water, the final product is superheated steam for power generation of a steam turbine, and the steam yield is determined by the condition of flue gas input by an owner through process calculation.

The device provided by the utility model has the function of generating saturated steam and superheated steam by recovering waste heat of high-temperature flue gas. The process flow of the utility model is as follows:

high-temperature flue gas generated by the gasification furnace enters from the side of the bottom of the waste heat boiler 1 after being dedusted by the cyclone separator, flows through the high-temperature radiation section 13, the high-temperature superheating section 12 and the medium-temperature evaporation section 11 in sequence, and is subjected to heat exchange with water in the waste heat boiler 1 to heat water in each section of the waste heat boiler 1, the temperature of the flue gas is gradually reduced, and finally reaches the temperature required by an owner, and the flue gas leaves from the top outlet of the waste heat boiler 1, and dust in the high-temperature flue gas is discharged from the dedusting outlet at the bottom of the waste heat boiler 1.

External feed water of the waste heat boiler 1 is pressurized by a vertical centrifugal pump from a downcomer pipeline 3 through a steam pocket 2 and a part of steam pocket water and then enters a high-temperature radiation section 13 and a water-cooled wall steam-water side inlet of a medium-temperature evaporation section 11 of the waste heat boiler 1, saturated steam-water mixture generated by the high-temperature radiation section 13 and the medium-temperature evaporation section 11 of the waste heat boiler 1 is discharged from a water-cooled wall outlet of the waste heat boiler 1 and enters each steam pocket 2 through an ascending pipe pipeline 4, steam-water separation is carried out in the steam drums 2 to form saturated steam, the saturated steam is led out from each steam drum 2 through a saturated steam pipeline 5, enters an inlet of a high-temperature superheating section 12 in the middle of the waste heat boiler 1, generates superheated steam meeting the requirements of an owner after absorbing heat of high-temperature flue gas, and enters an external superheated steam outlet pipe after passing through a high-temperature steam outlet pipe connected with the high-temperature superheating section 12 in the waste heat boiler 1 to leave the device.

The length of three sections in the waste heat boiler 1 is determined by process calculation, superheated steam is not necessarily generated only in the middle superheated section, if a proprietor needs superheated steam with higher pressure or temperature, the lowest high-temperature radiation section 13 can be used as the high-temperature superheated section 12 to generate superheated steam, and the other two ends are used for generating saturated steam.

The waste heat recovery device is used for the reconstruction project of the existing engineering unit, the existing equipment platform is fully utilized, the available horizontal space is small, the vertical space needs to be fully utilized, and the integration level of a waste heat recovery system is improved. The utility model carries out design optimization by the following means, and achieves the following effects:

1. the vertical multi-layer spiral coil pipe type water-cooled wall is adopted, so that the heat exchange efficiency can be improved, and the temperature of a flue gas outlet is further reduced;

2. integrate the over heater among the exhaust-heat boiler, then exhaust-heat boiler also can directly produce the over heater that can directly be used for the electricity generation, need not to arrange the over heater in addition and can directly satisfy owner's demand to the electricity generation steam, saves horizontal space simultaneously, reduces equipment frame and pipeline and support, reduces to build and operation maintenance cost.

Example 2

In this embodiment, the high-temperature flue gas waste heat recovery device of the present invention is provided with only one steam drum 2. The number of the circulating steam inlet ends of the waste heat boiler 1, the number of the circulating steam outlet ends of the waste heat boiler 1 and the number of the steam drums 2 are the same and are one; the number of the saturated steam inlet end of the waste heat boiler 1 and the number of the saturated steam outlet end of the waste heat boiler 1 are both one.

The rest is the same as in example 1.

Claims

1. The utility model provides a high temperature flue gas waste heat recovery device, a serial communication port, including exhaust-heat boiler (1) and at least one steam pocket (2), exhaust-heat boiler (1) is vertical pressure vessel, connect through downcomer pipeline (3) between the circulation steam inlet end of exhaust-heat boiler (1) and the circulation steam outlet end of steam pocket (2), connect through riser pipeline (4) between the circulation steam outlet end of exhaust-heat boiler (1) and the circulation steam inlet end of steam pocket (2), the feedwater entrance point and the water supply pipeline (6) of steam pocket (2) are connected, connect through saturated steam pipeline (5) between the saturated steam outlet end of steam pocket (2) and the saturated steam inlet end of exhaust-heat boiler (1).

2. A high temperature flue gas waste heat recovery device according to claim 1, wherein the downcomer pipe (3) is provided with a circulating pump (7) which makes the flow direction from the steam drum (2) to the waste heat boiler (1); the water supply pipeline (6) is provided with an adjusting valve.

3. The high-temperature flue gas waste heat recovery device according to claim 1, wherein a seventh port (107) for high-temperature flue gas to enter is arranged on the side of the bottom of the waste heat boiler (1); the waste heat boiler (1) comprises an external equipment barrel (18), a multi-section waste heat structure which is distributed up and down is arranged in the external equipment barrel (18), a port is respectively arranged at the position of each section of waste heat structure at two ends on the waste heat boiler (1), and a port is respectively arranged at two ends of the waste heat boiler (1).

4. The high-temperature flue gas waste heat recovery device according to claim 3, wherein the port of the waste heat boiler (1) located at the lower end of the waste heat structure and connected with the downcomer pipe (3) is the circulating steam inlet end of the waste heat boiler (1); the port, which is arranged at the upper end of the waste heat structure and connected with the ascending pipe pipeline (4), of the waste heat boiler (1) is a circulating steam outlet end of the waste heat boiler (1); the port, which is arranged at the lower end of the waste heat structure and connected with the saturated steam pipeline (5), of the waste heat boiler (1) is a saturated steam inlet end of the waste heat boiler (1); the port of the waste heat boiler (1) which is positioned at the upper end of the waste heat structure and is away from the high-temperature flue gas waste heat recovery device is the saturated steam outlet end of the waste heat boiler (1).

5. The high-temperature flue gas waste heat recovery device according to claim 3, wherein each section of waste heat structure in the external equipment cylinder (18) comprises an external screen type water-cooled wall (14), and the external screen type water-cooled walls (14) of any two adjacent sections of structures are connected through an expansion joint (15); a gap is arranged between the external screen type water-cooled wall (14) and the external equipment cylinder (18).

6. The high-temperature flue gas waste heat recovery device according to claim 5, wherein each section of waste heat structure in the external equipment cylinder (18) further comprises a spiral coil (16), and a plurality of layers of spiral coils (16) are arranged in a nested manner in the external screen type water-cooled wall (14); the multiple layers of spiral coil pipes (16) are communicated with each other, an inlet and an outlet are arranged on each layer of spiral coil pipe (16), and the inlet and the outlet are respectively connected to inlet and outlet headers at the upper end and the lower end of the waste heat structure through introducing pipes and leading-out pipes.

7. The high-temperature flue gas waste heat recovery device according to claim 6, wherein each layer of the spiral coil (16) is formed by spirally winding a plurality of heat exchange tubes into a cylindrical structure.

8. The high-temperature flue gas waste heat recovery device as claimed in claim 7, wherein the upper and lower adjacent circles of heat exchange tubes of each layer of the spiral coil (16) are hermetically welded together through fins (17).

9. The high-temperature flue gas waste heat recovery device according to claim 1, wherein the number of the circulating steam inlet ends of the waste heat boiler (1), the number of the circulating steam outlet ends of the waste heat boiler (1) and the number of the steam drums (2) are the same.

10. The high-temperature flue gas waste heat recovery device according to claim 1, wherein the steam drum (2) is a vertical or horizontal steam drum.