Device for improving heat efficiency of deslagging and heat recovery of circulating fluidized bed boiler

Abstract

The utility model discloses a device for improving the heat efficiency of slag discharge and heat recovery of a circulating fluidized bed boiler, which comprises a steam turbine system comprising a condensed water pipeline and a plurality of heaters arranged on the condensed water pipeline at intervals along the extension direction of the condensed water pipeline, the condensed water pipeline between two adjacent heaters forms a connecting pipe section; the boiler deslagging system comprises a slag cooler and a water return pipeline, the slag cooler is provided with a heat exchange flow channel, an inlet of the heat exchange flow channel is communicated with the liquid inlet end of the condensed water pipeline, the water return pipeline is communicated with an outlet of the heat exchange flow channel, the water return pipeline comprises a plurality of water return branch pipes, and the water return branch pipes are connected and communicated with the connecting pipe section and provided with stop valves. And the plurality of water return branch pipes are arranged corresponding to the plurality of connecting pipe sections. According to the device for improving the heat efficiency of deslagging and heat recovery of the circulating fluidized bed boiler, the deslagging heat can be stably and effectively recycled, and the circulating heat efficiency of a coal-fired unit is stably improved under all working conditions.

Description

TECHNICAL FIELD

[0001] The utility model relates to a boiler technical field especially is related to a device that improves circulating fluidized bed boiler deslagging heat recovery heat efficiency. BACKGROUND

[0002] In order to make full use of the various heat in the coal-fired power plant to improve the cycle heat efficiency, the coal-fired power plant has taken various technical measures and corresponding equipment or system, wherein, using the condensate water in the steam turbine system to absorb and cool the deslagging heat of the circulating fluidized bed boiler is also an energy-saving method and means. In the related art, when the deslagging heat of the circulating fluidized bed is recycled, the device or equipment for recycling the deslagging heat is not well adapted to the load change or coal change of the coal-fired unit to recycle the heat, which reduces the cycle heat efficiency of the coal-fired unit. SUMMARY

[0003] The utility model discloses at least solve one of the technical problems existing in the prior art. For this purpose, the utility model provides a device that improves circulating fluidized bed boiler deslagging heat recovery heat efficiency, the device that improves circulating fluidized bed boiler deslagging heat recovery heat efficiency can be well adapted to the load change or coal change of the coal-fired unit to recycle heat, and the cycle heat efficiency of the coal-fired unit is stably improved under full working condition.

[0004] According to the device that improves circulating fluidized bed boiler deslagging heat recovery heat efficiency of the utility model, including: steam turbine system, the steam turbine system includes condensate water pipeline and a plurality of heaters, a plurality of the heater is located at the condensate water pipeline and is along the extension direction interval arrangement of the condensate water pipeline, the condensate water pipeline between adjacent two the heater is formed into connecting pipe section;Boiler deslagging system, the boiler deslagging system includes cold slag ware and backwater pipeline, the cold slag ware has heat exchange flow channel, the inlet of the heat exchange flow channel is communicated with the liquid inlet end of the condensate water pipeline, the backwater pipeline is communicated with the outlet of the heat exchange flow channel, the backwater pipeline includes a plurality of backwater branch pipes, the backwater branch pipe is connected with the connecting pipe section and is communicated, the backwater branch pipe is equipped with stop valve, and a plurality of backwater branch pipes are arranged with a plurality of connecting pipe sections.

[0005] The device for improving heat recovery efficiency of circulating fluidized bed boiler slag discharge according to the utility model, through setting multiple backwater branch pipes on the backwater pipeline, the multiple backwater branch pipes are arranged in correspondence with the multiple connecting pipe sections of the condensate water pipeline, the backwater branch pipes are in communication with the outlet of the heat exchange flow channel in the cold slag device and the connecting pipe sections, the device is simple in structure and convenient to arrange, can well adapt to the change of slag discharge heat under the operating conditions of load change or coal change of the coal-fired unit, when the condensate water flowing back after recovering the slag discharge heat flows into the condensate water pipeline, the temperature of the condensate water can be always higher than the temperature of the condensate water in the condensate water pipeline at the position, so that the slag discharge heat can be stably and effectively recovered and utilized and the circulating heat efficiency of the coal-fired unit can be stably improved under full operating conditions.

[0006] In some embodiments of the utility model, multiple said heaters include shaft seal heater and first low pressure heater, shaft seal heater is adjacent to the liquid inlet end arrangement, first low pressure heater is adjacent to the shaft seal heater and is located in the condensate water flow direction of the shaft seal heater in the condensate water pipeline downstream, multiple said backwater branch pipe includes first branch pipe, first branch pipe is connected with the connecting pipe section between the shaft seal heater and the first low pressure heater and is communicated.

[0007] In an embodiment of the utility model, multiple said heaters also include second low pressure heater, second low pressure heater is adjacent to the first low pressure heater arrangement and is located in the condensate water flow direction of the first low pressure heater in the condensate water pipeline downstream, multiple said backwater branch pipe also includes second branch pipe, second branch pipe is connected with the connecting pipe section between the first low pressure heater and the second low pressure heater and is communicated.

[0008] In some embodiments of the utility model, the backwater pipeline also includes main backwater pipe, the main backwater pipe is connected with the outlet of the heat exchange flow channel and multiple said backwater branch pipes and is communicated.

[0009] In an embodiment of the utility model, the boiler slag discharge system also includes temperature sensor, temperature sensor is arranged in the main backwater pipe to detect the condensate water temperature flowing out of the heat exchange flow channel.

[0010] In some examples of the utility model, control system is also included, control system is electrically connected with temperature sensor and multiple said stop valve.

[0011] In some embodiments of the utility model, the boiler slag discharge system also includes backflow pipe, the backflow pipe is connected with the inlet of the heat exchange flow channel and the liquid inlet end of the condensate water pipeline and is communicated.

[0012] In some embodiments of the utility model, turbine system still include condensate pump, condensate pump's export with the liquid inlet end of condensate pipeline links to and communicates.

[0013] In some embodiments of the utility model, the slag cooler is a surface type slag cooler.

[0014] Additional aspects and advantages of the utility model will be partially given in the following description, some will become obvious from the following description, or be understood by the practice of the utility model. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is the schematic diagram of the device for improving heat efficiency of circulating fluidized bed boiler slag discharge heat recovery according to the utility model embodiments.

[0016] Reference signs:

[0017] 10, turbine system;

[0018] 11, condensate pipeline; 111, connecting pipe section;

[0019] 12, shaft seal heater; 13, first low pressure heater; 14, second low pressure heater; 15, condensate pump;

[0020] 20, boiler slag discharge system;

[0021] 21, slag cooler; 22, backflow pipe; 23, water return pipeline; 231, first branch pipe; 232, second branch pipe; 233, main water return pipe; 24, stop valve;

[0022] 100, the device for improving heat efficiency of circulating fluidized bed boiler slag discharge heat recovery. DETAILED DESCRIPTION

[0023] The embodiments of the utility model are described in detail below, and the examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the utility model, and cannot be understood as limiting the utility model.

[0024] The following refers to Figure 1 The device 100 for improving heat efficiency of circulating fluidized bed boiler slag discharge heat recovery according to the utility model embodiments is described.

[0025] As Figure 1As shown, the device 100 for improving heat efficiency of circulating fluidized bed boiler slag discharge and heat recovery according to the embodiment of the utility model, including: turbine system 10 and boiler slag discharge system 20, turbine system 10 includes condensate pipe 11 and multiple heaters, multiple heaters are arranged in the extension direction (such as Figure 1 The left and right direction) of condensate pipe 11, and the condensate pipe 11 between adjacent two heaters is formed into a connecting pipe section 111; boiler slag discharge system 20, boiler slag discharge system 20 includes a slag cooler 21 and a return water pipe 23, the slag cooler 21 has a heat exchange flow channel, the inlet of the heat exchange flow channel is communicated with the liquid inlet end of the condensate pipe 11, the return water pipe 23 is communicated with the outlet of the heat exchange flow channel, the return water pipe 23 includes multiple return water branch pipes, the return water branch pipes are connected and communicated with the connecting pipe sections 111, the return water branch pipes are provided with stop valves 24, and the multiple return water branch pipes are arranged correspondingly with the multiple connecting pipe sections 111.

[0026] In the embodiment, the turbine system 10 is provided with the condensate pipe 11 and multiple heaters, and the multiple heaters are arranged in the extension direction of the condensate pipe 11, which is simple in structure and can sequentially and multi-stage heat the condensate water flowing along the condensate pipe 11 by the multiple heaters, thereby meeting the heating needs of the condensate water.

[0027] In the embodiment, the boiler slag discharge system 20 is provided with the slag cooler 21 and the return water pipe 23, the inlet of the heat exchange flow channel in the slag cooler 21 is communicated with the liquid inlet end of the condensate pipe 11, and the return water pipe 23 is communicated with the outlet of the heat exchange flow channel, so that the condensate water from the condenser can flow along the condensate pipe 11 to be heated, another part of the condensate water can flow into the heat exchange flow channel of the slag cooler 21 to cool the boiler slag, correspondingly, the slag heat can heat the condensate water, so that the slag heat is recovered, and the heated condensate water can flow back to the condensate pipe 11 along the return water pipe 23 to be heated to the required temperature by the heaters and then returned to the boiler.

[0028] It can be understood that in the related art, the pipe for conveying the condensate water from the slag cooler 21 is usually connected with the condensate pipe 11 at a fixed position, and the condensate water temperature at the outlets of the heaters at different positions is different, in order to meet the needs of improving the heat efficiency, the condensate water temperature of the pipe flowing into the condensate pipe 11 is greater than the condensate water temperature in the condensate pipe 11 at the position, which makes the slag heat in the slag cooler 21 need to be kept stable, so that the condensate water can recover and utilize enough heat in the heat exchange flow channel to be heated to a sufficient stability.

[0029] However, in actual operation of the coal-fired power plant, due to the load change of the coal-fired unit or the change of the coal, the deslagging heat at the cold slag discharger 21 in the boiler deslagging system 20 is insufficient to ensure that the condensate water flowing back to the condensate pipeline 11 can stably have a temperature greater than the temperature of the condensate water in the condensate pipeline 11 at the position, so that the recovery of the deslagging heat cannot play a role in improving the thermal efficiency or even causes the thermal efficiency to decrease.

[0030] In the embodiment, the condensate pipeline 11 between the two adjacent heaters is provided with a connecting pipe section 111, the return water pipeline 23 is provided with a plurality of return water branch pipes, the plurality of return water branch pipes are arranged corresponding to the plurality of connecting pipe sections 111, the return water branch pipes are connected and communicated with the outlets of the heat exchange flow channels and the connecting pipe sections 111, and the return water branch pipes are provided with stop valves 24.

[0031] According to the device 100 for improving the thermal efficiency of the deslagging heat recovery of the circulating fluidized bed boiler, the plurality of return water branch pipes are arranged corresponding to the plurality of connecting pipe sections 111 of the condensate pipeline 11, the return water branch pipes are communicated with the outlets of the heat exchange flow channels in the connecting pipe sections 111 and the cold slag discharger 21, the structure is simple, the device 100 is convenient to arrange, and the device 100 can well adapt to the change of the deslagging heat under the operating conditions such as the load change of the coal-fired unit or the change of the coal, so that when the condensate water recovered from the deslagging heat flows back to the condensate pipeline 11, the temperature of the condensate water can always stably be greater than the temperature of the condensate water in the condensate pipeline 11 at the position, so that the deslagging heat can be stably and effectively recovered and utilized, and the circulating thermal efficiency of the coal-fired unit can be stably improved under all operating conditions.

[0032] In some embodiments of the utility model, as shown in Figure 1 The plurality of heaters can include a shaft seal heater 12 and a first low-pressure heater 13, the shaft seal heater 12 is arranged adjacent to the liquid inlet end, the first low-pressure heater 13 is adjacent to the shaft seal heater 12 and located downstream of the shaft seal heater 12 in the condensate water flow direction in the condensate pipeline 11, and the plurality of return water branch pipes include a first branch pipe 231, the first branch pipe 231 is connected and communicated with the connecting pipe section 111 between the shaft seal heater 12 and the first low-pressure heater 13.

[0033] The plurality of heaters in the embodiment includes a shaft seal heater 12 and a first low-pressure heater 13. The shaft seal heater 12 is arranged adjacent to the liquid inlet end of the condensate pipeline 11. The first low-pressure heater 13 is arranged adjacent to the shaft seal heater 12 and downstream of the shaft seal heater 12 in the condensate flow direction. The shaft seal heater 12 can heat the condensate by using the leakage steam at the shaft seal of the steam turbine, so that the leakage steam heat can be well recycled, and the circulating thermal efficiency of the coal-fired unit can be well improved. The first low-pressure heater 13 can heat the condensate by using the extracted low-pressure steam of the steam turbine, so as to meet the need of heating the condensate.

[0034] In the process of flowing of the condensate along the condensate pipeline 11, the condensate first flows through the shaft seal heater 12 for heating. After being heated, the condensate flows through the first low-pressure heater 13 for heating. The condensate temperature in the connecting pipe section 111 between the shaft seal heater 12 and the first low-pressure heater 13 is the condensate temperature at the outlet of the shaft seal heater 12 after being heated. The condensate temperature in the connecting pipe section 111 downstream of the first low-pressure heater 13 in the condensate flow direction is the condensate temperature after being heated by the first low-pressure heater 13. Therefore, the condensate temperature in the connecting pipe section 111 downstream of the first low-pressure heater 13 is greater than the condensate temperature in the connecting pipe section 111 between the shaft seal heater 12 and the first low-pressure heater 13.

[0035] In the embodiment, the return water branch pipes include a first branch pipe 231. The first branch pipe 231 is connected to and communicates with the connecting pipe section 111 between the shaft seal heater 12 and the first low-pressure heater 13. When the condensate temperature after being heated by the cold slag cooler 21 in the return pipeline 22 is greater than the condensate temperature after being heated by the shaft seal heater 12 and less than the condensate temperature after being heated by the first low-pressure heater 13, the stop valve 24 of the first branch pipe 231 is opened, and the stop valves 24 of the remaining return water branch pipes are closed. In this way, the condensate can flow to the connecting pipe section 111 between the shaft seal heater 12 and the first low-pressure heater 13 through the first branch pipe 231, so as to well meet the need of improving the circulating thermal efficiency of the coal-fired unit and stably and effectively recycle the slag heat.

[0036] In one embodiment of the utility model, as shown in Figure 1 The plurality of heaters in the embodiment includes a shaft seal heater 12 and a first low-pressure heater 13. The shaft seal heater 12 is arranged adjacent to the liquid inlet end of the condensate pipeline 11. The first low-pressure heater 13 is arranged adjacent to the shaft seal heater 12 and downstream of the shaft seal heater 12 in the condensate flow direction. The shaft seal heater 12 can heat the condensate by using the leakage steam at the shaft seal of the steam turbine, so that the leakage steam heat can be well recycled, and the circulating thermal efficiency of the coal-fired unit can be well improved. The first low-pressure heater 13 can heat the condensate by using the extracted low-pressure steam of the steam turbine, so as to meet the need of heating the condensate.

[0037] The heater in the embodiment further comprises a second low-pressure heater 14, which is arranged adjacent to the first low-pressure heater 13 and downstream of the first low-pressure heater 13 in the condensate flow direction. The arrangement is reasonable and can well meet the need of step-by-step heating of the condensate. The condensate temperature in the connecting pipe section 111 between the second low-pressure heater 14 and the first low-pressure heater 13 is the condensate temperature after being heated by the first low-pressure heater 13. In the embodiment, the return water branch pipe further comprises a second branch pipe 232, which is connected to the connecting pipe section 111 between the first low-pressure heater 13 and the second low-pressure heater 14, so that the condensate flowing to the condensate pipeline 11 can be well regulated and controlled by the first branch pipe 231 and the stop valve 24, and the device 100 for improving the heat recovery efficiency of the slag discharge of the circulating fluidized bed boiler can well meet the need of stably and effectively recovering and utilizing the heat of the slag discharge under different operating conditions of the coal-fired unit, so that the circulating heat efficiency of the coal-fired unit is stably improved under the whole operating condition.

[0038] For example, when the temperature of the condensate after being heated by the cold slag device 21 is greater than the temperature of the condensate after being heated by the first low-pressure heater 13 and less than the temperature of the condensate after being heated by the second low-pressure heater 14, the second branch pipe 232 is opened by the stop valve 24, the first branch pipe 231 is closed by the stop valve 24, and the condensate can flow to the connecting pipe section 111 between the first low-pressure heater 13 and the second low-pressure heater 14 along the second branch pipe 232. When the temperature of the condensate after being heated by the cold slag device 21 changes to be greater than the temperature of the condensate after being heated by the shaft seal heater 12 and less than the temperature of the condensate after being heated by the first low-pressure heater 13 when the operating load of the coal-fired unit changes or the coal changes, the second branch pipe 232 can be closed by the stop valve 24, the first branch pipe 231 can be opened by the stop valve 24, and the condensate can flow to the connecting pipe section 111 between the shaft seal heater 12 and the first low-pressure heater 13 along the first branch pipe 231.

[0039] In some embodiments of the utility model, as shown in Figure 1 The return water pipeline 23 can further comprise a main return water pipe 233, which is connected to and communicated with the outlet of the heat exchange flow channel and the plurality of return water branch pipes.

[0040] In the embodiment, the return water pipeline 23 further comprises a main return water pipe 233, which is connected to and communicated with the outlet of the heat exchange flow channel and the plurality of return water branch pipes. The structure is simple and the arrangement is reasonable, so that the condensate flowing out of the heat exchange flow channel can flow to the plurality of return water branch pipes along the main return water pipe 233, thereby cooperating with the stop valves 24 on the return water branch pipes to flexibly regulate and control the position of the condensate flowing into the condensate pipeline 11 as needed, so that the need of the condensate for water return can be well met.

[0041] In an embodiment of the utility model, referenceFigure 1 As shown, the boiler slag discharge system 20 can further include a temperature sensor arranged at the main return water pipe 233 to detect the temperature of the condensed water flowing out of the heat exchange flow channel.

[0042] In this embodiment, the temperature sensor is arranged at the main return water pipe 233 to detect the temperature of the condensed water flowing out of the heat exchange flow channel, and the arrangement is reasonable, so that the device 100 for improving the heat recovery efficiency of the circulating fluidized bed boiler slag discharge can obtain the temperature of the condensed water flowing out of the heat exchange flow channel in real time through the temperature sensor, thereby facilitating the multiple return water branch pipes to timely change the position of the condensed water flowing into the condensed water pipeline 11 according to the temperature of the condensed water, so that the condensed water from the boiler slag discharge system 20 flowing into the condensed water pipeline 11 can be more stably and reliably maintained to be greater than the temperature of the condensed water in the condensed water pipeline 11 at the position of the condensed water flowing in.

[0043] In some examples of the present application, the device 100 for improving the heat recovery efficiency of the circulating fluidized bed boiler slag discharge can further include a control system electrically connected with the temperature sensor and the multiple stop valves 24.

[0044] In this embodiment, the control system is electrically connected with the temperature sensor and the multiple stop valves 24, and the structure is simple, so that the device 100 for improving the heat recovery efficiency of the circulating fluidized bed boiler slag discharge can conveniently control the opening and closing of the multiple return water branch pipes according to the temperature parameter of the condensed water obtained by the temperature sensor through the control system, and the control is more convenient, so that the device can operate efficiently and stably.

[0045] In some embodiments of the present application, as shown in Figure 1 As shown, the boiler slag discharge system 20 further includes a return pipe 22 connected and communicated with the inlet of the heat exchange flow channel and the liquid inlet end of the condensed water pipeline 11.

[0046] In this embodiment, the boiler slag discharge system 20 further includes the return pipe 22 connected and communicated with the inlet of the heat exchange flow channel and the liquid inlet end of the condensed water pipeline 11, and the structure is simple, which can well meet the need of conveying the condensed water to the heat exchange flow channel of the slag cooler 21.

[0047] In some embodiments of the present application, as shown in Figure 1 As shown, the steam turbine system 10 can further include a condensed water pump 15, and the outlet of the condensed water pump 15 is connected and communicated with the liquid inlet end of the condensed water pipeline 11.

[0048] In this embodiment, the steam turbine system 10 further includes the condensed water pump 15, and the outlet of the condensed water cup is connected and communicated with the liquid inlet end of the condensed water pipeline 11, and the structure is simple, which can well meet the need of conveying the condensed water to the condensed water pipeline 11 and the slag cooler 21.

[0049] In some embodiments of this utility model, the slag cooler 21 can be a surface slag cooler.

[0050] In this embodiment, the slag cooler 21 is configured as a surface slag cooler. Surface slag coolers have advantages such as high cooling efficiency, low environmental impact, and strong adaptability, and can well meet the needs of boiler slag cooling and slag heat recovery.

[0051] The following will refer to Figure 1 The present invention describes an apparatus 100 for improving the thermal efficiency of heat recovery from slag discharge in a circulating fluidized bed boiler according to a specific embodiment of the present invention.

[0052] like Figure 1 As shown, the device 100 for improving the thermal efficiency of heat recovery from ash discharge in a circulating fluidized bed boiler includes a turbine system 10, a boiler ash discharge system 20, and a control system. The turbine system 10 includes a condensate pipeline 11, three heaters, and a condensate pump 15. The three heaters are a shaft seal heater 12, a first low-pressure heater 13, and a second low-pressure heater 14. The inlet end of the condensate pipeline 11 is connected to the outlet of the condensate pump 15. The shaft seal heater 12, the first low-pressure heater 13, and the second low-pressure heater 14 are arranged sequentially and at intervals along the condensate flow direction in the condensate pipeline 11. The condensate pipelines 11 between adjacent heaters form a connecting pipe section 111.

[0053] The boiler ash removal system 20 includes a ash cooler 21, a return pipe 22, a return water pipeline 23, a shut-off valve 24, and a temperature sensor. The return water pipeline 23 includes a main return water pipe 233 and two return water branch pipes, namely a first branch pipe 231 and a second branch pipe 232. Both the first branch pipe 231 and the second branch pipe 232 are equipped with shut-off valves 24. The first branch pipe 231 is connected to and communicates with the main return water pipe 233 and the connecting pipe section 111 between the shaft seal heater 12 and the first low-pressure heater 13. The second branch pipe 232 is connected to and communicates with the connecting pipe section 111 between the main return water pipe 233 and the first low-pressure heater 13 and the second low-pressure heater 14. The ash cooler 21 is equipped with a heat exchange channel. The main return water pipe 233 is connected to the outlet of the heat exchange channel. The temperature sensor is installed on the main return water pipe 233. The return pipe 22 is connected to the liquid inlet of the condensate pipeline 11 and the inlet of the heat exchange channel. The control system is electrically connected to the temperature sensor and three shut-off valves 24. For example, in the actual layout of a coal-fired power plant, the number of return branch pipes, valve positions, etc. can be determined based on historical data of the outlet water temperature of the slag cooler 21 under various operating conditions.

[0054] In the process of operating the device 100 for improving the heat recovery efficiency of the circulating fluidized bed boiler slag discharge and the stable operation of the coal-fired unit, when the slag cooler 21 has a large amount of slag discharge and a high slag discharge temperature, the slag discharge heat is large, and the condensed water has a high temperature after being heated by the slag cooler 21, when the temperature of the condensed water after being heated by the slag cooler 21 is higher than the temperature of the condensed water after being heated by the first low-pressure heater 13 in the condensed water pipeline 11, the first branch pipe 231 is closed by the stop valve 24, the second branch pipe 232 is opened by the stop valve 24, the condensed water flows into the connecting pipe section 111 between the first low-pressure heater 13 and the second low-pressure heater 14 along the second branch pipe 232, at this time, the temperature of the condensed water entering along the second branch pipe 232 is higher than the temperature of the condensed water at this position in the condensed water pipeline 11, and the condensed water is mixed and then flows into the second low-pressure heater 14 along the condensed water pipeline 11 for heating, so that the steam extraction amount of the second low-pressure heater 14 can be reduced, and then the work amount of the coal-fired unit is reduced, and the thermal efficiency of the coal-fired unit is improved.

[0055] When the operating load of the coal-fired unit changes or the coal changes, the slag discharge heat decreases, and the temperature of the condensed water heated by the slag cooler 21 decreases, and when the temperature of the condensed water is lower than the temperature of the condensed water heated by the first low-pressure heater 13 and higher than the temperature of the condensed water heated by the shaft seal heater 12, the control system can control the stop valve 24 of the first branch pipe 231 to be opened and the stop valve 24 of the second branch pipe 232 to be closed, so that the condensed water can flow into the connecting pipe section 111 between the shaft seal heater 12 and the first low-pressure heater 13 along the first branch pipe 231, thereby the temperature of the condensed water flowing into the condensed water pipeline 11 from the return water pipeline 23 can be always higher than the temperature of the condensed water at the flowing position in the condensed water pipeline 11 in the case that the operating condition of the coal-fired unit changes or in the case of the whole operating condition, so that the slag discharge heat can be stably and effectively recovered and utilized, and the circulating thermal efficiency of the coal-fired unit can be stably improved in the whole operating condition.

[0056] In the description of the utility model, it is understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the utility model.

[0057] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and do not connote or imply any relative importance or order of magnitude. Thus, features with "first", "second", "third" designations can include one or more of the features implicitly or explicitly. In the description of the present application, the meaning of "a plurality" is two or more, unless specifically defined otherwise.

[0058] In the present application, unless otherwise specifically defined and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected, or it can be communicated; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication or interaction between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0059] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0060] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A device for improving the thermal efficiency of ash discharge heat recovery in a circulating fluidized bed boiler, characterized in that, include: A steam turbine system (10) includes a condensate pipe (11) and a plurality of heaters. The plurality of heaters are located on the condensate pipe (11) and are spaced apart along the extension direction of the condensate pipe (11). The condensate pipe (11) between two adjacent heaters forms a connecting pipe section (111). The boiler ash removal system (20) includes a ash cooler (21) and a return water pipeline (23). The ash cooler (21) has a heat exchange channel. The inlet of the heat exchange channel is connected to the liquid inlet of the condensate pipeline (11). The return water pipeline (23) is connected to the outlet of the heat exchange channel. The return water pipeline (23) includes multiple return water branch pipes. The return water branch pipes are connected to and communicate with the connecting pipe section (111). The return water branch pipes are equipped with a shut-off valve (24). The multiple return water branch pipes are arranged correspondingly to the multiple connecting pipe sections (111).

2. The apparatus for improving the thermal efficiency of ash discharge heat recovery in a circulating fluidized bed boiler according to claim 1, characterized in that, The plurality of heaters include a shaft seal heater (12) and a first low-pressure heater (13). The shaft seal heater (12) is arranged adjacent to the liquid inlet. The first low-pressure heater (13) is adjacent to the shaft seal heater (12) and located downstream of the shaft seal heater (12) in the condensate flow direction in the condensate pipeline (11). The plurality of return water branches include a first branch (231). The first branch (231) is connected and communicates with the connecting pipe section (111) between the shaft seal heater (12) and the first low-pressure heater (13).

3. The apparatus for improving the thermal efficiency of ash discharge heat recovery in a circulating fluidized bed boiler according to claim 2, characterized in that, The plurality of heaters also includes a second low-pressure heater (14), which is arranged adjacent to the first low-pressure heater (13) and located downstream of the first low-pressure heater (13) in the condensate flow direction of the condensate pipe (11). The plurality of return water branch pipes also include a second branch pipe (232), which is connected to and communicates with the connecting pipe section (111) between the first low-pressure heater (13) and the second low-pressure heater (14).

4. The apparatus for improving the thermal efficiency of ash discharge heat recovery in a circulating fluidized bed boiler according to any one of claims 1-3, characterized in that, The return water pipeline (23) also includes a main return water pipe (233), which is connected to and communicates with the outlet of the heat exchange channel and multiple return water branch pipes.

5. The apparatus for improving the thermal efficiency of ash discharge heat recovery in a circulating fluidized bed boiler according to claim 4, characterized in that, The boiler ash discharge system (20) also includes a temperature sensor located on the main return water pipe (233) to detect the temperature of the condensate flowing out of the heat exchange channel.

6. The apparatus for improving the thermal efficiency of ash discharge heat recovery in a circulating fluidized bed boiler according to claim 5, characterized in that, It also includes a control system that is electrically connected to the temperature sensor and the plurality of shut-off valves (24).

7. The apparatus for improving the thermal efficiency of ash discharge heat recovery in a circulating fluidized bed boiler according to any one of claims 1-3, characterized in that, The boiler ash discharge system (20) also includes a return pipe (22), which is connected to and communicates with the inlet of the heat exchange channel and the liquid inlet of the condensate pipeline (11).

8. The apparatus for improving the thermal efficiency of ash discharge heat recovery in a circulating fluidized bed boiler according to any one of claims 1-3, characterized in that, The turbine system (10) also includes a condensate pump (15), the outlet of which is connected to and in communication with the inlet of the condensate pipeline (11).

9. The apparatus for improving the thermal efficiency of ash discharge heat recovery in a circulating fluidized bed boiler according to any one of claims 1-3, characterized in that, The slag cooler (21) is a surface slag cooler.

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