阅读说明：本技术 一种屏式过热器系统 (Screen type superheater system ) 是由 李铁 莫春鸿 李维成 黎懋亮 冉燊铭 陈灿 潘绍成 李旭升 陈红 徐启明 于 2020-07-17 设计创作，主要内容包括：本发明公开了一种屏式过热器系统,包括进口集箱、若干屏U形管屏和出口集箱；进口集箱和出口集箱均包括大集箱和安装在大集箱上的若干个小集箱；若干屏U形管屏沿着锅炉的炉宽方向布置,每屏U形管屏包括沿着锅炉的炉深方向并联布置的前排管屏和后排管屏,每屏U形管屏的前排管屏和后排管屏与同一进口小集箱和同一出口小集箱分别相连；进口集箱与出口集箱在高度方向上呈上下部布置且进口大集箱与出口大集箱布置在U形管屏的同一侧。本发明通过优化现有屏式过热器大集箱布置位置,优化工质在进、出口小集箱中的流动方向,使前、后排管屏各管在进、出口小集箱的压差偏差更小,工质流量更均匀,实现减小工质侧出口壁温存在较大系统性偏差的目的。(The invention discloses a platen superheater system, which comprises an inlet header, a plurality of platen U-shaped tube platens and an outlet header; the inlet header and the outlet header both comprise a large header and a plurality of small headers arranged on the large header; the U-shaped tube panels are arranged along the width direction of the boiler, each U-shaped tube panel comprises a front tube panel and a rear tube panel which are arranged in parallel along the depth direction of the boiler, and the front tube panel and the rear tube panel of each U-shaped tube panel are respectively connected with a same inlet small header and a same outlet small header; the inlet header and the outlet header are arranged at the upper part and the lower part in the height direction, and the inlet large header and the outlet large header are arranged at the same side of the U-shaped tube panel. The invention optimizes the arrangement position of the large header of the existing platen superheater and the flowing direction of the working medium in the small headers at the inlet and the outlet, so that the pressure difference deviation of the pipes of the front and the rear tube panel at the small headers at the inlet and the outlet is smaller, the flow of the working medium is more uniform, and the purpose of reducing the large systematic deviation of the wall temperature of the outlet at the side of the working medium is realized.)

1. A platen superheater system is characterized by comprising an inlet header, a plurality of platen U-shaped tube platens and an outlet header;

the inlet header and the outlet header both comprise a large header and a plurality of small headers arranged on the large header;

the U-shaped tube panels are arranged along the width direction of the boiler, each U-shaped tube panel comprises a front tube panel and a rear tube panel which are arranged in parallel along the depth direction of the boiler, and the front tube panel and the rear tube panel of each U-shaped tube panel are respectively connected with a same inlet small header and a same outlet small header;

the inlet header and the outlet header are arranged at the upper part and the lower part in the height direction, and the inlet large header and the outlet large header are arranged at the same side of the U-shaped tube panel.

2. The platen superheater system of claim 1, wherein the platen superheater system is arranged above a boiler furnace, the boiler is an opposed firing pulverized coal boiler in which burners under subcritical parameters or supercritical parameters are arranged on front and rear walls of the furnace, a tangential firing pulverized coal boiler in which burners under subcritical parameters or supercritical parameters are arranged on corners of the furnace and walls of the furnace, or a "W" flame firing pulverized coal boiler in which burners under subcritical parameters or supercritical parameters are arranged on arches of the front and rear walls of the furnace.

3. The platen superheater system of claim 1, wherein the inlet header and the outlet header are each comb-shaped, the large header being horizontally arranged parallel to a front wall or a rear wall of the boiler, and the small header being horizontally arranged parallel to a side wall of the boiler and vertically mounted on the large header.

4. The platen superheater system of claim 1, wherein the U-shaped tube platen is vertically arranged parallel to the boiler side wall, and the front row tube platen and the rear row tube platen of the U-shaped tube platen each comprise a plurality of U-shaped tubes arranged in parallel and having two ends connected to the inlet small header and the outlet small header, respectively, wherein the flow direction of the working medium in the U-shaped tube platen is set to be opposite to the flow direction of the flue gas: the front tube panel is in parallel flow, and the rear tube panel is in reverse flow.

5. The platen superheater system according to claim 1, wherein the inlet header and the outlet header are arranged in a height direction with upper and lower portions of the inlet header above and the outlet header below or the inlet header below and the outlet header above.

6. The platen superheater system of claim 1, wherein the inlet header and the outlet header are disposed on the same side of the U-tube platen, both on a furnace front side or a furnace rear side of the U-tube platen.

7. The platen superheater system of claim 1, wherein the working fluid flow of the platen superheater system is, in order: the device comprises a large inlet collecting box, a small inlet collecting box, a U-shaped tube panel, a small outlet collecting box and a large outlet collecting box, wherein the flow direction of the working medium relative to the small inlet collecting box and the small outlet collecting box is in a horizontal U shape.

8. The platen superheater system of claim 1, wherein the small inlet header is provided with a plurality of diameters of orifice structures at positions corresponding to the openings for connecting the U-shaped tube panels, so as to finely adjust the flow rates of the working fluid between the front tube panel and the rear tube panel in the U-shaped tube panels and the different U-shaped tubes in the same tube panel.

9. The platen superheater system according to claim 1, wherein the U-shaped tube panels are arranged with 7-30 panels along a width direction of the boiler, and the number of U-shaped tubes in each panel is 10-30 tubes in a front row panel and a rear row panel.

10. The platen superheater system according to claim 1, wherein the tube panel lengths of the plurality of platen U-shaped tube panels arranged along the width direction of the boiler are the same or different, the length of the front tube panel and the length of the rear tube panel in each platen U-shaped tube panel are the same or different, and the length, material, diameter and wall thickness of the U-shaped tubes in the front tube panel or the rear tube panel are set to be the same or different.

Technical Field

The invention relates to the technical field of boiler design, in particular to a platen superheater system capable of reducing wall temperature deviation and preventing wall temperature from being over-heated.

Background

The boiler receives the hot offset of hot side mainly depends on the uneven coefficient of the hot side heat load, the uneven coefficient of structure and the uneven coefficient of flow, the platen superheater of current supercritical pulverized coal boiler arranges in the furnace top, be many screens along furnace width direction quantity, arrange a screen along furnace depth direction, including preceding, back row tube panel, the parallel U-shaped that is of tube panel pipe arranges, the platen superheater advances, the export collection case is including big respectively, little collection case, be the comb shape structure, big collection case is on a parallel with the boiler before, the back wall, little collection case is installed perpendicularly on big collection case, advance, export collection case is arranged from top to bottom along the direction of height. The positions of the early inlet and outlet large headers along the depth direction of the furnace are that one is in the front direction of the U-shaped tube panel furnace and the other is in the rear direction of the U-shaped tube panel furnace, and the U-shaped tube panel is in the middle, as shown in figure 1.

Working medium flow: the working medium outlet wall temperature of the screen superheater arranged in the way is actually measured (approximately representing the working medium temperature), and systematic deviation of about 20 ℃ exists in the values of the wall temperatures of the working medium outlet walls of the front and rear tube bank screen plates of the screen superheater.

The analysis shows that the reasons are mainly as follows: the pressure difference between the front calandria panel and the small header at the inlet and outlet is large, the pressure difference between the rear calandria panel and the small header at the outlet and the inlet and outlet is small, so that the working medium flow of the rear calandria panel is low, the flow non-uniform coefficient is large, and the wall temperature deviation is large.

Disclosure of Invention

The invention provides a screen superheater system which reduces wall temperature deviation and prevents wall temperature overtemperature by optimizing the arrangement position of a large screen superheater header and optimizing the flow direction of a working medium in a small inlet header and a small outlet header by optimizing the flow direction of the working medium in the small inlet header and the small outlet header.

The invention provides a platen superheater system, which comprises an inlet header, a plurality of platen U-shaped tube platens and an outlet header;

the inlet header and the outlet header both comprise a large header and a plurality of small headers arranged on the large header;

the U-shaped tube panels are arranged along the width direction of the boiler, each U-shaped tube panel comprises a front tube panel and a rear tube panel which are arranged in parallel along the depth direction of the boiler, and the front tube panel and the rear tube panel of each U-shaped tube panel are respectively connected with a same inlet small header and a same outlet small header;

the inlet header and the outlet header are arranged at the upper part and the lower part in the height direction, and the inlet large header and the outlet large header are arranged at the same side of the U-shaped tube panel.

According to one embodiment of the platen superheater system of the invention, the platen superheater system is arranged above a boiler furnace, and the boiler is an opposed firing pulverized coal boiler in which burners under subcritical parameters or supercritical parameters are arranged on front and rear walls of the furnace, a tangential firing pulverized coal boiler in which burners under subcritical parameters or supercritical parameters are arranged on corners of the furnace and walls of the furnace, or a "W" flame firing pulverized coal boiler in which burners under subcritical parameters or supercritical parameters are arranged on arches of the front and rear walls of the furnace.

According to an embodiment of the platen superheater system of the present invention, the inlet header and the outlet header are both comb-shaped structures, the large header is horizontally arranged parallel to the front wall or the rear wall of the boiler, and the small header is horizontally arranged parallel to the side wall of the boiler and vertically mounted on the large header.

According to an embodiment of the platen superheater system of the present invention, the U-shaped tube panels are vertically arranged parallel to the boiler side wall, the front tube panel and the rear tube panel of the U-shaped tube panels each include a plurality of U-shaped tubes arranged in parallel and having two ends respectively connected to the small inlet header and the small outlet header, wherein the flow direction of the working medium in the U-shaped tube panels is set to be relative to the flow direction of the flue gas as follows: the front tube panel is in parallel flow, and the rear tube panel is in reverse flow.

According to an embodiment of the platen superheater system according to the present invention, the inlet header and the outlet header are arranged in a height direction with the inlet header up and the outlet header down or with the inlet header down and the outlet header up.

According to an embodiment of the platen superheater system of the present invention, the large inlet header and the large outlet header are disposed on the same side of the U-shaped tube platen and are both disposed on the furnace front side or the furnace rear side of the U-shaped tube platen.

According to one embodiment of the platen superheater system of the present invention, the working medium flow of the platen superheater system is sequentially as follows: the device comprises a large inlet collecting box, a small inlet collecting box, a U-shaped tube panel, a small outlet collecting box and a large outlet collecting box, wherein the flow direction of the working medium relative to the small inlet collecting box and the small outlet collecting box is in a horizontal U shape.

According to an embodiment of the platen superheater system of the invention, the small inlet header is provided with a throttle hole structure with multiple diameters at the position of the opening corresponding to the connection of the U-shaped tube panels, so as to finely adjust the working medium flow between the front tube panel and the rear tube panel in the U-shaped tube panels and different U-shaped tubes in the same tube panel.

According to an embodiment of the platen superheater system of the invention, the U-shaped tube panels are arranged with 7-30 panels along the width direction of the boiler, and the number of U-shaped tubes of a front tube panel and a rear tube panel in each U-shaped tube panel is 10-30 respectively.

According to one embodiment of the platen superheater system of the present invention, the tube panel lengths of the plurality of platen U-shaped tube panels arranged along the width direction of the boiler are the same or different, the length of the front tube panel and the length of the rear tube panel in each platen U-shaped tube panel are the same or different, and the length, material, diameter and wall thickness of the U-shaped tubes in the front tube panel or the rear tube panel are set to be the same or different.

Compared with the conventional scheme, the screen type superheater system provided by the invention optimizes the arrangement position of the large header of the existing screen type superheater and optimizes the flow direction of the working medium in the small inlet and outlet headers, so that the pressure difference deviation of the pipes of the front and rear tube array screens in the small inlet and outlet headers is smaller, the flow of the working medium is more uniform, and the purpose of reducing the large systematic deviation of the wall temperature of the side outlet of the working medium is realized, thereby better preventing the wall temperature of the heating surface of the screen type superheater from being over-heated, ensuring the operation safety of the heating surface, prolonging the service life and ensuring that the operation parameter (steam temperature) meets the design requirement.

Drawings

FIG. 1 shows a schematic layout of a platen superheater system of the prior art.

FIG. 2 is a schematic diagram showing an application structure of a platen superheater system in the invention.

FIGS. 3A and 3B illustrate two arrangements of inlet and outlet headers, respectively, in a platen superheater system in accordance with an exemplary embodiment of the present invention.

Fig. 4A shows a schematic view of a main view structure and a schematic view of a working fluid flow direction of a platen superheater system according to an exemplary embodiment of the present invention, fig. 4B shows a schematic view of a left view structure and a schematic view of a working fluid flow direction of a platen superheater system according to an exemplary embodiment of the present invention, and fig. 4C shows a schematic view of a top view structure and a schematic view of a working fluid flow direction of a platen superheater system according to an exemplary embodiment of the present invention.

Description of reference numerals:

1-inlet large collecting box, 2-inlet small collecting box, 3-front exhaust tube panel, 4-rear exhaust tube panel, 5-outlet small collecting box, 6-outlet large collecting box, 7-burner, 8-hearth, 9-panel superheater system, 10-high temperature superheater and 11-low temperature superheater.

Detailed Description

All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.

Any feature disclosed in this specification may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.

The principles and construction of the platen superheater system of the present invention will be explained in detail.

According to the invention, the wall temperature data of the outlet of the heating surface of the platen superheater in the prior art as shown in figure 1 is tested, and the heat load non-uniform coefficient, the structure non-uniform coefficient and the flow non-uniform coefficient which cause the wall temperature deviation of the heating surface of the boiler are comprehensively analyzed. Under the condition that the uneven heat load coefficients and the uneven structure coefficients of the front calandria screen and the rear calandria screen are not greatly different, analyzing the static distribution of the small inlet and outlet headers of the front calandria screen and the rear calandria screen, analyzing the pressure difference of the tubes of the same screen, calculating the uneven flow coefficient of the same screen, optimizing the arrangement position of the large header in the existing screen superheater and the flow direction of the working medium in the small header, and optimizing the arrangement mode that the original inlet and outlet large headers are respectively arranged at the front side and the rear side of the U-shaped tube screen and the U-shaped tube screen is arranged in the middle of the U-shaped tube screen into the arrangement mode that the inlet and outlet large headers are arranged at the same side of the U-shaped tube screen (including the front side or the rear side of the furnace), so that the flow direction of the working medium in the screen superheater system is changed from Z-shaped to horizontal U-shaped, and the pressure difference of the tubes of the front calandria screen and the rear calandria screen is closer to the small inlet, The working medium flow is more uniform, the working medium enthalpy is more uniformly increased, and the wall temperature deviation between the pipes is smaller.

FIG. 2 is a schematic diagram showing an application structure of a platen superheater system in the invention. As shown in fig. 2, the platen superheater system 1 of the present invention is disposed above a boiler furnace 8, a high temperature superheater 10 is disposed in the boiler furnace, a low temperature superheater 11 is disposed in a tail flue, and the specific application structure will be specifically described in embodiment 1.

The boiler applied by the invention can be a convection combustion pulverized coal boiler with a burner 7 arranged on the front wall and the rear wall of a hearth under subcritical parameters or supercritical parameters, such as a 300MW (350MW) grade, a 600MW (660MW) grade, a 1000MW grade and a higher capacity convection combustion boiler; the boiler can also be a tangential firing pulverized coal boiler with the burners 7 arranged on the corners and the furnace walls of the hearth under the subcritical parameters or the supercritical parameters or a W flame firing pulverized coal boiler with the burners 7 arranged on the arches of the front and the rear walls of the hearth under the subcritical parameters or the supercritical parameters, such as a 600MW grade supercritical W flame boiler and the like. Therefore, systematic deviation of wall temperatures of front and rear tube bank screen working medium side outlets of a heating surface of the screen superheater can be reduced, overtemperature of the wall temperature of the heating surface of the screen superheater can be prevented better, operating parameters (steam temperature) are guaranteed, and the deep peak regulation capacity of the boiler is improved.

FIGS. 3A and 3B illustrate two arrangements of inlet and outlet headers, respectively, in a platen superheater system in accordance with an exemplary embodiment of the present invention. Fig. 4A shows a schematic view of a main view structure and a schematic view of a working fluid flow direction of a platen superheater system according to an exemplary embodiment of the present invention, fig. 4B shows a schematic view of a left view structure and a schematic view of a working fluid flow direction of a platen superheater system according to an exemplary embodiment of the present invention, and fig. 4C shows a schematic view of a top view structure and a schematic view of a working fluid flow direction of a platen superheater system according to an exemplary embodiment of the present invention.

As shown in fig. 3A-4C, the platen superheater system includes an inlet header, several platen U-tube platens, and an outlet header in accordance with an exemplary embodiment of the present invention. Wherein, import collection case and export collection case all include big collection case and install a plurality of little collection cases on big collection case, import collection case promptly includes import big collection case 1 and import little collection case 2, and export collection case includes export big collection case 6 and export little collection case 5.

As shown in fig. 4A to 4C, the inlet header and the outlet header are both comb-shaped structures, the large header is horizontally arranged parallel to the front wall or the rear wall of the boiler, and the small header is horizontally arranged parallel to the side wall of the boiler and vertically installed on the large header.

The U-shaped tube panels are arranged along the width direction of the boiler, each U-shaped tube panel comprises a front tube panel 3 and a rear tube panel 4 which are arranged in parallel along the depth direction of the boiler, and the front tube panel 3 and the rear tube panel 4 of each U-shaped tube panel are respectively connected with a same inlet small header and a same outlet small header. Wherein, the furnace depth direction is arranged between the front wall and the rear wall of the boiler, and the furnace width direction is arranged between the two side walls.

The U-shaped tube panels are vertically arranged in parallel to the side wall of the boiler, the front tube panel 3 and the rear tube panel 4 of each U-shaped tube panel respectively comprise a plurality of U-shaped tubes which are arranged in parallel and the two ends of each U-shaped tube panel are respectively connected with the small inlet header and the small outlet header, and the U-shaped tubes are arranged in a U shape. Wherein, the relative flue gas flow direction of working medium flow direction in the U-shaped tube panel sets up to: the front tube panel is in parallel flow, and the rear tube panel is in reverse flow. Because the boiler flue gas flows from the front of the boiler to the back of the boiler, and the working medium in the front exhaust tube panel also flows from the front of the boiler to the back of the boiler, the two directions are the same and form a concurrent flow; the working medium in the back row tube panel flows from the back of the furnace to the front of the furnace, and the working medium flow in opposite directions and are in counter flow.

Wherein, the inlet header and the outlet header are arranged at the upper part and the lower part in the height direction, and the inlet large header 1 and the outlet large header 6 are arranged at the same side of the U-shaped tube panel. Specifically, the inlet header and the outlet header are arranged in the height direction with the inlet header up and the outlet header down or the inlet header down and the outlet header up, which can be adjusted according to the actual situation.

The inlet large header 1 and the outlet large header 6 are arranged on the same side of the U-shaped tube panel and are uniformly arranged on the furnace front side or the furnace rear side of the U-shaped tube panel, as shown in fig. 3A and 3B.

Therefore, the working medium flow of the platen superheater system sequentially comprises the following steps: the device comprises an inlet large header 1, an inlet small header 2, a U-shaped tube panel, an outlet small header 5 and an outlet large header 6, wherein the flow direction of a working medium relative to the inlet small header and the outlet small header is horizontal U-shaped, so that the pressure difference of the front tube panel and the rear tube panel of the panel superheater in the inlet small header and the outlet small header is closer, the flow of the working medium is more uniform, the enthalpy of the working medium is more uniform, and the wall temperature deviation between tubes is smaller.

In addition, the throttling hole structures with various diameters are arranged at the positions, corresponding to the openings of the U-shaped tube panels, of the small inlet header 1, so that the working medium flow between the front tube panel and the rear tube panel in the U-shaped tube panels and the working medium flow of different U-shaped tubes in the same tube panel are finely adjusted, the wall temperature deviation between the tubes of the heating surface is smaller (the wall temperature is reduced from about 20 ℃ to about 5 ℃), and the wall temperature of the heating surface of the screen superheater is better prevented from being over-heated.

Preferably, 7-30U-shaped tube panels are arranged along the width direction of the boiler, the number of U-shaped tubes of a front tube panel and a rear tube panel in each U-shaped tube panel is 10-30, and technicians can adjust the U-shaped tube panels according to actual working conditions.

In addition, the tube panel lengths of a plurality of panel U-shaped tube panels arranged along the width direction of the boiler can be set to be the same or different, the length of a front tube panel and the length of a rear tube panel in each panel U-shaped tube panel can also be set to be the same or different, and the length, the material, the diameter and the wall thickness of a U-shaped tube in the front tube panel or the rear tube panel can also be set to be the same or different according to the difference between the smoke temperature of the U-shaped tube and the working medium temperature, so that the whole panel superheater is more flexible and has more adjustability.

By applying the invention, the temperature deviation of the wall of the side outlet of the working medium of the platen superheater can be obviously reduced and the overtemperature of the heating surface can be avoided under the conditions of not increasing the manufacturing cost of the boiler and not generating any negative influence, so that the running parameter (steam temperature) can be better ensured to reach the design value, and the deep peak regulation capability of the boiler can be improved.

Also, there are experimental data showing: the difference values of the wall temperatures of the front tube panel working medium outlet and the rear tube panel working medium outlet of the platen superheater in the prior art and the platen superheater in the invention (the difference value of the wall temperature of the rear tube panel minus the wall temperature of the front tube panel) are respectively 23.3 ℃ and 5.3 ℃, and the effect of reducing the wall temperature deviation is very obvious.

According to a project with two 1000MW units, the annual load rate is 80%, the price of coal entering a factory is 700 yuan/ton, the main steam temperature at 1.0 ℃ affects the coal consumption by 0.088g/KWh, the application of the invention can improve the main steam temperature by 2.0 ℃, the project can save the fire coal by 2466 ton/year, and the expenditure is reduced by 172.6 ten thousand yuan/year; the boiler is reduced by one non-stop for three years, the economic loss of one non-stop is 900 ten thousand yuan (more conservative), namely 300 ten thousand yuan/year,reduce the project operation cost by 472.6 ten thousand yuan/year in total, and simultaneously can reduce NOx and SO₂And dust is discharged, so that the environment is protected. In addition, the application of the invention is also beneficial to the recovery of the quality guarantee money of the equipment (the main steam temperature deviates from the guarantee value of 1.0 ℃ and the penalty of 200 RMB), and the product reputation and the market competitiveness of a boiler manufacturing unit are improved.

The present invention will be further described with reference to the following specific examples.