Steam air preheating devices and systems

Abstract

This invention discloses a steam-air preheating device and system. The device includes: a housing, a condensate heat exchange section, a low-pressure steam heat exchange section, a high-pressure steam heat exchange section, and a flash tank. The inlet header of the high-pressure steam heat exchange section is connected to a first extraction steam pipe, and the outlet header of the high-pressure steam heat exchange section is connected to the inlet of the flash tank. The inlet header of the low-pressure steam heat exchange section is connected to a second extraction steam pipe and the first outlet of the flash tank. The inlet header of the condensate heat exchange section is connected to the outlet header of the low-pressure steam heat exchange section and the second outlet of the flash tank. The steam-air preheating device and system provided by this invention effectively utilize steam and condensate to recover heat, improve heat exchange efficiency, reduce steam extraction, avoid water hammer, and make the system operation more economical, efficient, safe, and reliable.

Description

Technical Field

[0001] The embodiments of the present invention relate to boiler technology, and more particularly to a steam air preheating device and system. Background Art

[0002] Air preheater is a device that increases the boiler air supply temperature by preheating the air before it enters the boiler. It has the functions of increasing the combustion temperature in the furnace, improving combustion efficiency, saving fuel, and reducing flue gas emissions. In order to promote full combustion of fuel, the boiler needs to use an air preheater to increase the primary air temperature to about 200°C. Since there are more acidic gases in the flue gas at the tail of the boiler, which are highly corrosive, if the waste heat of the flue gas is used to heat the primary air through the air preheater, there will be serious dust accumulation and corrosion problems, which will shorten the service life of the air preheater and affect the normal operation of the boiler.

[0003] In order to avoid the harm caused by flue gas waste heat to the air preheater, most power plant boilers currently use steam air preheaters to preheat the primary air through the steam heating surface.

[0004] However, the steam extraction volume of the steam-type air preheater is relatively large, which wastes the energy of condensed water, seriously loses the high quality energy of steam, reduces the heat absorption rate of the system, and is prone to water hammer. Summary of the invention

[0005] The embodiment of the present invention provides a steam air preheating device and system to effectively utilize steam and condensed water to recover heat, improve heat exchange efficiency, reduce steam extraction, avoid water hammer, and make the operation of the system more economical, efficient, safe and reliable.

[0006] In a first aspect, an embodiment of the present invention provides a steam air preheating device, comprising: a box, a condensate heat exchange section, a low-pressure steam heat exchange section, a high-pressure steam heat exchange section and a flash tank; wherein,

[0007] The condensate heat exchange section, the low-pressure steam heat exchange section, and the high-pressure steam heat exchange section are arranged in the box body; the box body is provided with an inlet and an outlet;

[0008] The inlet header of the high-pressure steam heat exchange section is connected to the first steam extraction pipeline, and the outlet header of the high-pressure steam heat exchange section is connected to the inlet of the flash tank;

[0009] The inlet header of the low-pressure steam heat exchange section is connected to the second steam extraction pipeline and the first outlet of the flash tank;

[0010] The inlet header of the condensed water heat exchange section is connected to the outlet header of the low-pressure steam heat exchange section and the second outlet of the flash tank.

[0011] Optionally, the first steam extraction pipeline is a steam drum extraction pipeline, and the inlet header of the high-pressure steam heat exchange section is connected to the boiler drum through the steam drum extraction pipeline;

[0012] The second steam extraction pipeline is a steam turbine steam extraction pipeline, and the inlet header of the low-pressure steam heat exchange section is connected to the steam turbine through the steam turbine steam extraction pipeline.

[0013] Optionally, the outlet header of the high-pressure steam heat exchange section is connected to the flash tank via a first drain pipe, and the outlet header of the high-pressure steam heat exchange section and the first drain pipe are arranged outside the box body;

[0014] The outlet header of the low-pressure steam heat exchange section is connected to the inlet header of the condensate heat exchange section through a second drain pipe, and the outlet header of the low-pressure steam heat exchange section and the second drain pipe are arranged outside the box body.

[0015] Optionally, a first air thermometer is provided at the outlet of the box, and a first pressure gauge and a first electric regulating valve are provided on the steam drum extraction pipeline;

[0016] A second air thermometer is provided between the low-pressure steam heat exchange section and the high-pressure steam heat exchange section, and a second pressure gauge and a second electric regulating valve are provided on the steam turbine extraction pipeline;

[0017] A third air thermometer is provided between the condensed water heat exchange section and the low-pressure steam heat exchange section, and a fourth air thermometer is provided at the inlet of the box.

[0018] Optionally, the first outlet of the flash tank is connected to the inlet header of the low-pressure steam heat exchange section through a flash steam pipeline, and the second outlet of the flash tank is connected to the inlet header of the condensate heat exchange section through a third drain pipeline.

[0019] Optionally, the outlet header of the condensate heat exchange section is connected to the deaerator via a fourth drain pipe, and the outlet header of the condensate heat exchange section and the fourth drain pipe are arranged outside the box body.

[0020] Optionally, the condensate heat exchange section, the low-pressure steam heat exchange section, and the high-pressure steam heat exchange section are sequentially arranged in the box body from bottom to top, the inlet of the box body is located at the bottom of the box body, and the outlet of the box body is located at the top of the box body.

[0021] Optionally, a guide plate is further provided at the inlet of the box.

[0022] Optionally, the box includes an inlet box, a first box, a second box, a third box and an outlet box connected in sequence;

[0023] The inlet of the box is arranged at the inlet box, and the outlet of the box is arranged at the outlet box;

[0024] The condensed water heat exchange section is arranged in the first box body, the low-pressure steam heat exchange section is arranged in the second box body, and the high-pressure steam heat exchange section is arranged in the third box body.

[0025] In a second aspect, an embodiment of the present invention further provides a steam-air preheating system, comprising the steam-air preheating device according to any embodiment of the present invention; wherein:

[0026] The first steam extraction pipeline of the high-pressure steam heat exchange section is connected to the boiler drum;

[0027] The second steam extraction pipeline of the low-pressure steam heat exchange section is connected to the steam turbine;

[0028] The fourth drain pipe of the condensate heat exchange section is connected to the deaerator.

[0029] The steam air preheating device and system provided in the embodiment of the present invention can make the air to be preheated enter the box and then pass through three stages of condensate heat exchange section, low-pressure steam heat exchange section and high-pressure steam heat exchange section for heat exchange. The flash steam and hydrophobicity are separated by a flash tank, and the low-pressure steam, high-pressure steam and condensate are combined to provide thermal energy for the device, so that the air to be preheated is heated to a specified temperature and then flows out of the box, solving the problems of large steam extraction amount, low heat absorption rate and easy water hammer in the prior art, achieving the effect of effectively utilizing steam and condensate to recover heat, improving heat exchange efficiency, reducing steam extraction amount, avoiding the occurrence of water hammer, and making the operation of the system more economical, efficient, safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a structural schematic diagram of a steam air preheating device provided in Embodiment 1 of the present invention;

[0031] Figure 2 It is a structural schematic diagram of a steam air preheating device provided in Embodiment 2 of the present invention;

[0032] Figure 3 is a structural schematic diagram of another steam air preheating device provided in Embodiment 2 of the present invention;

[0033] Figure 4 It is a structural schematic diagram of a steam air preheating system provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0035] Embodiment 1

[0036] At present, most power plant boilers use steam air preheaters, and the primary air is preheated by passing through the two-stage steam heating surfaces of the low-pressure section and the high-pressure section in sequence. The primary air is first heated by the low-pressure heating surface of the steam turbine extraction, and then heated by the high-pressure heating surface of the steam drum extraction. The condensed water produced after the two-stage steam heating is sent to the deaerator through the drain pipe.

[0037] However, the above-mentioned air preheater is heated only by extracting steam from the low-pressure steam turbine and the high-pressure steam drum. The steam extraction volume is large, and the condensate produced after the two-stage heating directly enters the deaerator, which wastes the energy of the condensate, seriously loses the high quality energy of the steam, and reduces the heat absorption rate of the system. In addition, since the temperature and pressure of the condensate in the high-pressure steam section are relatively high and accompanied by some uncondensed steam, directly entering the deaerator will cause the temperature and pressure of the deaerator to be too high, resulting in water hammer.

[0038] Based on the above problems, an embodiment of the present invention provides a steam air preheating device. Figure 1 , Figure 1 This is a schematic diagram of the structure of a steam air preheating device provided in the first embodiment of the present invention. This embodiment can be applied to the case of increasing the temperature of the primary air used in a waste incineration power generation boiler. The device specifically includes: a box 100, a condensed water heat exchange section 200, a low-pressure steam heat exchange section 300, a high-pressure steam heat exchange section 400 and a flash tank 500; wherein,

[0039] The condensate heat exchange section 200, the low-pressure steam heat exchange section 300, and the high-pressure steam heat exchange section 400 are arranged in the box body 100; the box body 100 is provided with an inlet 110 and an outlet 120;

[0040] The inlet header 410 of the high-pressure steam heat exchange section 400 is connected to the first steam extraction pipeline 430, and the outlet header 420 of the high-pressure steam heat exchange section 400 is connected to the inlet 510 of the flash tank 500;

[0041] The inlet header 310 of the low-pressure steam heat exchange section 300 is connected to the second steam extraction pipeline 330 and the first outlet 520 of the flash tank 500;

[0042] The inlet header 210 of the condensate heat exchange section 200 is connected to the outlet header 320 of the low-pressure steam heat exchange section 300 and the second outlet 530 of the flash tank 500 .

[0043] The steam-air preheating device provided in an embodiment of the present invention can be applied to waste incineration power generation boilers. The device adopts three-stage steam preheating, that is, the air to be preheated passes through the condensate heat exchange section, the low-pressure steam heat exchange section, and the high-pressure steam heat exchange section in sequence, so that the primary air temperature meets the boiler combustion requirements.

[0044] Specifically, an inlet 110 and an outlet 120 are provided on the box body 100. The air to be preheated from the garbage storage pit flows upward from the inlet 110, passes through the condensate heat exchange section 200, the low-pressure steam heat exchange section 300, and the high-pressure steam heat exchange section 400 in sequence, is heated to about 200°C, and flows out from the outlet 120 of the box body 100.

[0045] Among them, serpentine heat exchange pipes can be set in the condensate heat exchange section 200, the low-pressure steam heat exchange section 300, and the high-pressure steam heat exchange section 400. After steam or condensate is passed into the serpentine heat exchange pipes, heat can be exchanged with the surrounding air.

[0046] The first steam extraction pipeline 430 is used to extract high-pressure steam. The high-pressure steam enters the heat exchange pipeline in the high-pressure steam heat exchange section 400 through the inlet header 410, and becomes high-pressure condensed water after heat exchange with the air to be preheated, and flows into the flash tank 500 from the outlet header 420 through the inlet 510.

[0047] After the high-pressure condensed water flashes in the flash tank 500, flash steam and drain are formed. The flash steam enters the inlet header 310 of the low-pressure steam heat exchange section 300 through the first outlet 520 of the flash tank 500, and the drain enters the inlet header 210 of the condensed water heat exchange section 200 through the second outlet 530 of the flash tank 500.

[0048] Among them, the flash tank 500 is used to reduce the pressure of the high-pressure and high-temperature fluid. Specifically, the high-pressure condensed water with a relatively high pressure enters the relatively low-pressure container for flash 500, and can be converted into saturated water vapor and saturated water with the flash 500 pressure, that is, flash steam and hydrophobicity. The setting of the flash tank 500 has the advantage of avoiding the water hammer phenomenon caused by the high-pressure condensed water directly entering the deaerator, and making full use of the thermal energy of the high-pressure condensed water, so that after it is converted into hydrophobicity, it continues to provide heat for the device.

[0049] The second steam extraction pipeline 330 is used to extract low-pressure steam. The low-pressure steam enters the heat exchange pipeline in the low-pressure steam heat exchange section 300 through the inlet header 310. The low-pressure steam and flash steam are mixed and become low-pressure condensate after heat exchange with the air to be preheated. The low-pressure steam enters the inlet header 210 of the condensate heat exchange section 200 from the outlet header 320.

[0050] The low-pressure condensate and drain enter the heat exchange pipe in the condensate heat exchange section 200 through the inlet header 210, and become low-temperature condensate after heat exchange with the air to be preheated, which can be discharged to the deaerator through the drain pipe.

[0051] The steam air preheating device provided in the embodiment of the present invention can make the air to be preheated enter the box and then pass through three stages of heat exchange, namely, a condensed water heat exchange section, a low-pressure steam heat exchange section, and a high-pressure steam heat exchange section, to perform heat exchange. The high-pressure condensed water is separated into flash steam and hydrophobicity through a flash tank, and the low-pressure steam, high-pressure steam, and condensed water are combined to provide thermal energy for the device, so that the air to be preheated is heated to a specified temperature and then flows out of the box, thereby solving the problems of large steam extraction volume, low heat absorption rate, and easy occurrence of water hammer in the prior art, achieving the effect of effectively utilizing steam and condensed water to recover heat, improving heat exchange efficiency, and reducing steam extraction volume, thus avoiding the occurrence of water hammer and making the system run more economically, efficiently, safely, and reliably.

[0052] Embodiment 2

[0053] Figure 2 A schematic diagram of the structure of a steam air preheating device provided in the second embodiment of the present invention, based on the above technical solution, optionally, refer to Figure 2 The first steam extraction pipeline 430 is a steam drum extraction pipeline, and the inlet header 410 of the high-pressure steam heat exchange section 400 is connected to the boiler drum through the steam drum extraction pipeline;

[0054] The second steam extraction pipeline 330 is a steam turbine steam extraction pipeline, and the inlet header 310 of the low-pressure steam heat exchange section 300 is connected to the steam turbine through the steam turbine steam extraction pipeline.

[0055] The steam drum extraction pipeline can extract the high-pressure steam in the boiler drum and enter the high-pressure steam heat exchange section 400 through the inlet header 410 .

[0056] The steam turbine extraction pipeline enters the low-pressure steam heat exchange section 300 through the inlet header 310 .

[0057] Optionally, the outlet header 420 of the high-pressure steam heat exchange section 400 is connected to the flash tank 500 via a first drain pipe 440 , and the outlet header 420 of the high-pressure steam heat exchange section 400 and the first drain pipe 440 are arranged outside the box body 100 .

[0058] The first drain pipe 440 is used to discharge high-pressure condensed water, and the first drain pipe 440 may further include a pressure gauge and a drain valve. The pressure gauge is used to monitor the pressure in the first drain pipe 440.

[0059] Optionally, the outlet header 320 of the low-pressure steam heat exchange section 300 is connected to the inlet header 210 of the condensate heat exchange section 200 through a second drain pipe 340 , and the outlet header 320 of the low-pressure steam heat exchange section 300 and the second drain pipe 340 are arranged outside the box body 100 .

[0060] The second drain pipe 340 is used to discharge low-pressure condensed water, and the second drain pipe 340 may further include a pressure gauge and a drain valve. The pressure gauge is used to monitor the pressure in the second drain pipe 340.

[0061] Optionally, a first air thermometer 130 is provided at the outlet 120 of the housing 100 , and a first pressure gauge 450 and a first electric regulating valve 460 are provided on the steam drum extraction pipeline.

[0062] Among them, the first air thermometer 130 is used to monitor the air temperature at the outlet 120 to determine whether the preheated air meets the preset temperature after heating; the first pressure gauge 450 is used to monitor the pressure of high-pressure steam in the first steam extraction pipe 430; the first electric regulating valve 460 is used to adjust the steam flow in the first steam extraction pipe 430, and can monitor and adjust the operating parameters of the device in real time.

[0063] Specifically, the first electric regulating valve 460 can adjust the steam flow in the first steam extraction pipeline 430 according to the monitoring results of the first air thermometer 130 and the first pressure gauge 450. For example, when the first air thermometer 130 monitors that the air temperature at the outlet 120 is close to the preset temperature, the steam flow in the first steam extraction pipeline 430 can be adjusted by the first electric regulating valve 460; when the first pressure gauge 450 monitors that the pressure of the high-pressure steam in the first steam extraction pipeline 430 is too large and exceeds the preset normal value, the steam flow in the first steam extraction pipeline 430 can be adjusted by the first electric regulating valve 460.

[0064] Optionally, a second air thermometer 140 is provided between the low-pressure steam heat exchange section 300 and the high-pressure steam heat exchange section 400 , and a second pressure gauge 350 and a second electric regulating valve 360 ​​are provided on the steam turbine extraction pipeline.

[0065] Among them, the second air thermometer 140 is used to monitor the air temperature between the low-pressure steam heat exchange section 300 and the high-pressure steam heat exchange section 400; the second pressure gauge 350 is used to monitor the pressure of the low-pressure steam in the second steam extraction pipe 330; the second electric regulating valve 360 ​​is used to adjust the steam flow in the second steam extraction pipe 330, and can monitor and adjust the operating parameters of the device in real time.

[0066] Specifically, the second electric regulating valve 360 ​​can adjust the steam flow in the second steam extraction pipeline 330 according to the monitoring results of the second air thermometer 140 and the second pressure gauge 350. For example, when the second air thermometer 140 monitors that the air temperature between the low-pressure steam heat exchange section 300 and the high-pressure steam heat exchange section 400 is too low, the steam flow in the second steam extraction pipeline 330 can be adjusted by the second electric regulating valve 360; when the second pressure gauge 350 monitors that the pressure of the low-pressure steam in the second steam extraction pipeline 330 is too high and exceeds the preset normal value, the steam flow in the second steam extraction pipeline 330 can be adjusted by the second electric regulating valve 360.

[0067] Optionally, the first outlet 520 of the flash tank 500 is connected to the inlet header 310 of the low-pressure steam heat exchange section 300 through a flash steam pipe 540 , and the second outlet 530 of the flash tank 500 is connected to the inlet header 210 of the condensate heat exchange section 200 through a third drain pipe 550 .

[0068] Specifically, the flash steam pipeline 540 is used to deliver the flash steam separated by the flash tank 500 to the inlet header 310 of the low-pressure steam heat exchange section 300. The flash steam pipeline 540 may also include a pressure gauge and a regulating valve, wherein the regulating valve may be used to adjust the flash steam flow rate according to the pressure value of the flash steam in the flash steam pipeline 540 monitored by the pressure gauge, so that the device can operate safely and stably.

[0069] The third drain pipe 550 is used to discharge the drain separated by the flash tank 500 and send it to the inlet header 210 of the condensate heat exchange section 200. The third drain pipe 550 may also include a pressure gauge and a drain valve. The pressure gauge is used to monitor the pressure of the gas and liquid in the third drain pipe 550. The drain valve is used to discharge the drain in the third drain pipe 550 and prevent leakage.

[0070] Optionally, the outlet header 220 of the condensate heat exchange section 200 is connected to the deaerator via a fourth drain pipe 230 , and the outlet header 220 of the condensate heat exchange section 200 and the fourth drain pipe 230 are arranged outside the box body 100 .

[0071] The fourth drain pipe 230 can discharge the low-temperature condensed water to the deaerator, wherein the fourth drain pipe 230 may further include a regulating valve for adjusting the flow of the low-temperature condensed water in the fourth drain pipe 230 according to actual needs.

[0072] Optionally, a third air thermometer 150 is provided between the condensate heat exchange section 200 and the low-pressure steam heat exchange section 300 , and a fourth air thermometer 160 is provided at the inlet 110 of the box body.

[0073] Among them, the third air thermometer 150 is used to monitor the air temperature between the condensate heat exchange section 200 and the low-pressure steam heat exchange section 300 in real time. The setting of the third air thermometer 150 can provide a reference for the heat exchange effect of the condensate heat exchange section 200. If the temperature display is lower than the preset value, it can be judged that the current heat exchange effect of the condensate heat exchange section 200 is poor, and the operating parameters of the device can be adjusted according to actual needs.

[0074] The fourth air thermometer 160 is used to monitor the air temperature at the inlet 110. The advantage of this arrangement is that the temperature of the air to be preheated at the inlet 110 can be monitored in real time, and the operating parameters of the device can be adjusted in time according to the temperature to achieve the best heat exchange effect.

[0075] Optionally, the condensate heat exchange section 200, the low-pressure steam heat exchange section 300, and the high-pressure steam heat exchange section 400 are sequentially arranged in the box body 100 from bottom to top, the inlet 110 of the box body 100 is located at the bottom of the box body 100, and the outlet of the box body 100 is located at the top of the box body 100.

[0076] Specifically, the condensate heat exchange section 200 may include a condensate heat exchange pipe 240, which is connected end to end with the inlet header 210 and the outlet header 220, and is used to pass low-pressure condensate and drain to exchange heat with the air to be preheated.

[0077] The low-pressure steam heat exchange section 300 may include a low-pressure steam heat exchange pipe 350, which is connected end to end with the inlet header 310 and the outlet header 320 for introducing flash steam and low-pressure steam to exchange heat with the air to be preheated.

[0078] The high-pressure steam heat exchange section 400 may include a high-pressure steam heat exchange pipe 470, which is connected end to end with the inlet header 410 and the outlet header 420 for introducing high-pressure steam to exchange heat with the air to be preheated.

[0079] Among them, the condensate heat exchange pipe 240, the low-pressure steam heat exchange pipe 350 and the high-pressure steam heat exchange pipe 470 are all serpentine heat exchange pipes.

[0080] Optionally, a guide plate 170 is further provided at the inlet 110 of the box body 100 .

[0081] Specifically, the guide plate 170 can be set as an arc-shaped guide plate to guide the air to be preheated, so that the air to be preheated can flow upward quickly, preventing the air to be preheated from the inlet 110 from accumulating in the corners of the box 100 under the drive of the fan, thereby accelerating the air flow and improving the preheating efficiency.

[0082] It should be noted that Figure 2The shapes, positions and structures of the box body 100, condensate heat exchange section 200, low-pressure steam heat exchange section 300, high-pressure steam heat exchange section 400, and guide plate 170 shown in the figure are only used to illustrate a possible implementation of the embodiment of the present invention, and are not used to limit the embodiment of the present invention. In actual application, the device should be set according to the specific situation.

[0083] The working principle of the steam air preheating device provided in the embodiment of the present invention is as follows:

[0084] The fan installed at the inlet 110 delivers the preheated air from the garbage storage pit into the box 100, and passes through the condensed water heat exchange section 200, the low-pressure steam heat exchange section 300, and the high-pressure steam heat exchange section 400 from bottom to top, and exchanges heat with the heat exchange pipes of the three sections respectively, and is heated to a specified temperature (usually about 200°C), and then flows out from the outlet 120 and is sent to the boiler furnace; the high-pressure steam from the boiler drum enters the inlet header 410 of the high-pressure steam heat exchange section 400 through the first steam extraction pipe 430, and becomes high-pressure condensed water after heat exchange through the high-pressure steam heat exchange pipe 470, and enters the flash tank 500 through the first drain pipe 440; the high-pressure condensed water in the flash tank 500 After the internal flash evaporation, flash steam and drain are formed. The flash steam enters the inlet header 310 of the low-pressure steam heat exchange section 300 through the flash steam pipe 540, and the drain enters the inlet header 210 of the condensate heat exchange section 200 through the third drain pipe 550; the low-pressure steam from the steam turbine enters the inlet header 310 of the low-pressure steam heat exchange section 300 through the second steam extraction pipe 330, and is converted into low-pressure condensate after heat exchange with the flash steam through the low-pressure steam heat exchange pipe 350, and enters the inlet header 210 of the condensate heat exchange section 200 through the second drain pipe 340, and is converted into low-temperature condensate after heat exchange with the drain through the condensate heat exchange pipe 240, and is discharged to the deaerator through the fourth drain pipe 230.

[0085] Figure 3 is a schematic diagram of the structure of another steam air preheating device provided in the second embodiment of the present invention, and optionally, reference Figure 3 , based on the above technical solution, the box includes an inlet box 600, a first box 610, a second box 620, a third box 630 and an outlet box 640 connected in sequence;

[0086] The inlet 110 of the box is arranged at the inlet box 600, and the outlet 120 of the box is arranged at the outlet box 640;

[0087] The condensate heat exchange section 200 is disposed in the first box body 610 , the low-pressure steam heat exchange section 300 is disposed in the second box body 620 , and the high-pressure steam heat exchange section 400 is disposed in the third box body 630 .

[0088] The inlet box 600, the first box 610, the second box 620, the third box 630 and the outlet box 640 may be five independent boxes, and two adjacent boxes may be connected by angle steel flanges.

[0089] Manholes may be provided at the middle and lower parts of the second box body 620 and the third box body 630, respectively, to facilitate workers to enter the condensate heat exchange section 200 and the high-pressure steam heat exchange section 400 to inspect and repair the equipment.

[0090] The steam air preheating device provided in the embodiment of the present invention can make the air to be preheated enter the box and then pass through three stages of heat exchange, namely, a condensed water heat exchange section, a low-pressure steam heat exchange section, and a high-pressure steam heat exchange section, to exchange heat. The flash steam and hydrophobicity are separated by a flash tank, and the low-pressure steam, high-pressure steam, and condensed water are combined to provide thermal energy for the device, so that the air to be preheated is heated to a specified temperature and then flows out of the box, thereby solving the problems of large steam extraction volume, low heat absorption rate, and easy occurrence of water hammer in the prior art, achieving the effect of effectively utilizing steam and condensed water to recover heat, improving heat exchange efficiency, and reducing steam extraction volume, thus avoiding the occurrence of water hammer and making the system run more economically, efficiently, safely, and reliably.

[0091] Embodiment 3

[0092] This embodiment also provides a steam air preheating system, Figure 4 is a schematic diagram of a steam air preheating system provided in an embodiment of the present invention, and optionally, reference Figure 4 , the system includes the steam air preheating device provided by any embodiment of the present invention; wherein,

[0093] The first steam extraction pipeline 430 of the high-pressure steam heat exchange section 400 is connected to the boiler drum 710;

[0094] The second steam extraction pipeline 330 of the low-pressure steam heat exchange section 300 is connected to the steam turbine 720;

[0095] The fourth drain pipe 230 of the condensate heat exchange section 200 is connected to the deaerator 730 .

[0096] In actual application, the fan can drive the preheated air at the inlet 110 to flow into the box 100, and then pass through the condensate heat exchange section 200, the low-pressure steam heat exchange section 300, and the high-pressure steam heat exchange section 400 for heating. After being heated to the specified temperature, it flows out from the outlet 120.

[0097] The boiler drum 710 can provide high-pressure steam for the high-pressure steam heat exchange section 400, and exchange heat with the air to be preheated in the high-pressure steam heat exchange section 400; the steam turbine 720 can provide low-pressure steam for the low-pressure steam heat exchange section 300, and exchange heat with the air to be preheated in the low-pressure steam heat exchange section 300; the low-temperature condensate generated by the air preheating device heating the air to be preheated can be discharged to the deaerator 730 through the outlet header 220 and the fourth drain pipe 230.

[0098] It should be noted that Figure 4 It is only used to illustrate the relative positions and connection relationships between the boiler drum 710, the turbine 720 and the deaerator 730 and the air preheating device, and is not used to limit the air preheating system provided in the embodiment of the present invention.

[0099] The steam air preheating system provided in the embodiment of the present invention includes the steam air preheating device provided in any embodiment of the present invention, and has the corresponding functional structure and beneficial effects of the device.

[0100] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A steam air preheating device, characterized in that: include: Box, condensate heat exchange section, low-pressure steam heat exchange section, high-pressure steam heat exchange section and flash tank; among which, The condensate heat exchange section, the low-pressure steam heat exchange section, and the high-pressure steam heat exchange section are arranged in the box body; the box body is provided with an inlet and an outlet; The inlet header of the high-pressure steam heat exchange section is connected to the first steam extraction pipeline, and the outlet header of the high-pressure steam heat exchange section is connected to the inlet of the flash tank; The inlet header of the low-pressure steam heat exchange section is connected to the second steam extraction pipeline and the first outlet of the flash tank; The inlet header of the condensed water heat exchange section is connected to the outlet header of the low-pressure steam heat exchange section and the second outlet of the flash tank; The first steam extraction pipeline is a steam drum extraction pipeline, and the inlet header of the high-pressure steam heat exchange section is connected to the boiler drum through the steam drum extraction pipeline; The second steam extraction pipeline is a steam turbine steam extraction pipeline, and the inlet header of the low-pressure steam heat exchange section is connected to the steam turbine through the steam turbine steam extraction pipeline; The outlet header of the high-pressure steam heat exchange section is connected to the flash tank via a first drain pipe, and the outlet header of the high-pressure steam heat exchange section and the first drain pipe are arranged outside the box body; The outlet header of the low-pressure steam heat exchange section is connected to the inlet header of the condensate heat exchange section through a second drain pipe, and the outlet header of the low-pressure steam heat exchange section and the second drain pipe are arranged outside the box body; The first outlet of the flash tank is connected to the inlet header of the low-pressure steam heat exchange section through a flash steam pipeline, and the second outlet of the flash tank is connected to the inlet header of the condensate heat exchange section through a third drain pipeline.

2. The device according to claim 1, characterized in that A first air thermometer is provided at the outlet of the box, and a first pressure gauge and a first electric regulating valve are provided on the steam drum extraction pipeline; A second air thermometer is provided between the low-pressure steam heat exchange section and the high-pressure steam heat exchange section, and a second pressure gauge and a second electric regulating valve are provided on the steam turbine extraction pipeline; A third air thermometer is provided between the condensed water heat exchange section and the low-pressure steam heat exchange section, and a fourth air thermometer is provided at the inlet of the box.

3. The device according to claim 1, characterized in that The outlet header of the condensate heat exchange section is connected to the deaerator through a fourth drain pipe, and the outlet header of the condensate heat exchange section and the fourth drain pipe are arranged outside the box body.

4. The device according to claim 1, characterized in that The condensate heat exchange section, the low-pressure steam heat exchange section, and the high-pressure steam heat exchange section are sequentially arranged in the box body from bottom to top, the inlet of the box body is located at the bottom of the box body, and the outlet of the box body is located at the top of the box body.

5. The device according to claim 1, characterized in that A guide plate is also provided at the inlet of the box.

6. The device according to claim 1, characterized in that The box body comprises an inlet box body, a first box body, a second box body, a third box body and an outlet box body which are connected in sequence; The inlet of the box is arranged at the inlet box, and the outlet of the box is arranged at the outlet box; The condensed water heat exchange section is arranged in the first box body, the low-pressure steam heat exchange section is arranged in the second box body, and the high-pressure steam heat exchange section is arranged in the third box body.

7. A steam air preheating system, characterized in that: The steam-air preheating device comprises any one of claims 1 to 6; wherein the first steam extraction pipeline of the high-pressure steam heat exchange section is connected to the boiler drum; The second steam extraction pipeline of the low-pressure steam heat exchange section is connected to the steam turbine; The fourth drain pipe of the condensate heat exchange section is connected to the deaerator.

Images