Waste heat recovery system of slag cooler, control method and device of system

Abstract

The application discloses a kind of cold slag device waste heat recovery system, the control method and device of system, wherein the system includes: cold slag device, cold slag device is divided into high-temperature heat exchange zone and low-temperature heat exchange zone;High-temperature heat exchange zone water inlet flow adjusting valve;Low-temperature heat exchange zone water inlet flow adjusting valve;High-pressure heater heat recovery system;Low-pressure heater heat recovery system;High-temperature heat exchange zone water outlet to each high-pressure heater outlet stop valve;Low-temperature heat exchange zone water outlet to each low-pressure heater outlet stop valve;Boiler slag door, with the high-temperature heat exchange zone of cold slag device's inlet slag port is connected;Slag bin, with the low-temperature heat exchange zone of cold slag device's slag outlet is connected;Wherein, boiler slag exported by boiler slag door is sent to slag bin after heat release in high-temperature heat exchange zone, low-temperature heat exchange zone in sequence.The application can make cold slag device reduce heat exchange loss, reach the purpose of energy saving.

Description

Technical Field

[0001] This invention relates to the field of circulating fluidized bed boiler technology, and in particular to a waste heat recovery system for a slag cooler, a control method for the system, and a device thereof. Background Technology

[0002] This section is intended to provide background or context for the embodiments of the invention set forth in the claims. The description herein is not an admission that it is prior art simply because it is included in this section.

[0003] Circulating fluidized bed boilers have been widely adopted in the industry due to their wide fuel adaptability and low pollution. Because circulating fluidized bed boilers typically use high-ash, low-calorific-value inferior coal, they produce a large amount of ash discharge at a high temperature of approximately 850℃, resulting in significant ash heat.

[0004] Currently, the common method for recovering heat from ash discharge in circulating fluidized bed boilers is to add a ash cooler. Specifically, this involves using condensate from the low-pressure heater's regenerative system to absorb the waste heat from the boiler ash discharge, and then returning the heated condensate to the low-pressure heater's regenerative system. However, according to empirical data, the ash temperature at the ash cooler inlet is approximately 850℃, while the ash temperature at the outlet is approximately 150℃. The water temperature at the ash cooler inlet is 48℃, and the water temperature at the outlet is 98℃. It is evident that the temperature difference between the ash and water is too large, resulting in significant heat exchange issues. Despite the loss, there is still significant potential for energy saving; moreover, in actual operation, if the return water position of the slag cooler is improper and the return water temperature is lower than the main condensate temperature at the inlet point, it will actually reduce the efficiency of waste heat utilization. Summary of the Invention

[0005] This invention provides a waste heat recovery system for a slag cooler, used to reduce the temperature difference between water and slag in the slag cooler, thereby improving heat exchange efficiency. To further reduce losses, achieve energy conservation, improve the thermal economy of the unit, and avoid reducing the effectiveness of waste heat utilization, the system includes:

[0006] A slag cooler, which is divided into a high-temperature heat exchange zone and a low-temperature heat exchange zone;

[0007] The inlet water flow regulating valve for the high-temperature heat exchange zone is used to regulate the inlet water flow for the high-temperature heat exchange zone.

[0008] The inlet water flow regulating valve for the low-temperature heat exchange zone is used to regulate the inlet water flow for the low-temperature heat exchange zone.

[0009] The high-pressure heater regenerative system includes a first high-pressure heater, a second high-pressure heater, and a third high-pressure heater, used to heat the cooling water output from the outlet of the high-temperature heat exchange zone;

[0010] The low-pressure heater regenerative system includes a first low-pressure heater, a second low-pressure heater, and a third low-pressure heater, which are used to heat the cooling water output from the outlet of the low-temperature heat exchange zone.

[0011] The high-temperature heat exchange zone outlet water to the first high-pressure heater outlet stop valve, the high-temperature heat exchange zone outlet water to the second high-pressure heater outlet stop valve, and the high-temperature heat exchange zone outlet water to the third high-pressure heater outlet stop valve are used to control the high-temperature heat exchange zone outlet water to any high-pressure heater.

[0012] The low-temperature heat exchange zone outlet water to the first low-pressure heater outlet stop valve, the low-temperature heat exchange zone outlet water to the second low-pressure heater outlet stop valve, and the low-temperature heat exchange zone outlet water to the third low-pressure heater outlet stop valve are used to control the low-temperature heat exchange zone outlet water to any low-pressure heater.

[0013] The boiler ash discharge door is connected to the ash inlet of the high-temperature heat exchange zone of the ash cooler.

[0014] The slag bin is connected to the slag discharge outlet of the low-temperature heat exchange zone of the slag cooler.

[0015] Among them, the boiler slag discharged from the boiler slag discharge gate passes through the high-temperature heat exchange zone and the low-temperature heat exchange zone in sequence to release heat before being sent to the slag bin.

[0016] This invention also provides a control method for a waste heat recovery system in a slag cooler, used to reduce the heat exchange temperature difference between water and slag in the slag cooler, thereby improving heat exchange efficiency. To further reduce losses, achieve energy conservation, improve the thermal economy of the unit, and avoid reducing the effectiveness of waste heat utilization, this method includes:

[0017] When the inlet flow regulating valve of the high-temperature heat exchange zone and the inlet flow regulating valve of the low-temperature heat exchange zone are both in automatic temperature control mode, the first condensate temperature at the outlet condensate temperature measuring point of the low-temperature heat exchange zone is collected; the second condensate temperature at the condensate temperature measuring point of the first low-pressure heater, the third condensate temperature at the condensate temperature measuring point of the second low-pressure heater, and the fourth condensate temperature at the condensate temperature measuring point of the third low-pressure heater are collected; the condensate temperature difference between the first condensate temperature and the second, third, and fourth condensate temperatures are calculated respectively; the low-pressure heater with the smallest condensate temperature difference is determined; a preset time period is set, and it is determined whether the condensate temperature difference of the low-pressure heater with the smallest condensate temperature difference is still the smallest within the preset time period. If so, the outlet shut-off valve of the low-temperature heat exchange zone to the outlet of the low-pressure heater with the smallest temperature difference is opened; the outlet shut-off valves of the low-temperature heat exchange zone to the outlet of the other two low-pressure heaters are closed.

[0018] When the inlet water flow regulating valve of the high-temperature heat exchange zone and the inlet water flow regulating valve of the low-temperature heat exchange zone are both in automatic temperature control mode, the first feedwater temperature at the outlet feedwater temperature measuring point of the high-temperature heat exchange zone is collected; the second feedwater temperature at the feedwater temperature measuring point of the first high-pressure heater, the third feedwater temperature at the feedwater temperature measuring point of the second high-pressure heater, and the fourth feedwater temperature at the feedwater temperature measuring point of the third high-pressure heater are collected; the feedwater temperature difference between the first feedwater temperature and the second, third, and fourth feedwater temperatures are calculated respectively; the high-pressure heater with the smallest feedwater temperature difference is determined; a preset time period is set, and it is determined whether the feedwater temperature difference of the high-pressure heater with the smallest feedwater temperature difference is still the smallest within the preset time period. If so, the outlet water from the high-temperature heat exchange zone to the outlet shut-off valve of the high-pressure heater with the smallest temperature difference is opened; the outlet water from the high-temperature heat exchange zone to the outlet shut-off valves of the other two high-pressure heaters is closed.

[0019] This invention also provides a control device for a waste heat recovery system of a slag cooler, used to reduce the heat exchange temperature difference between water and slag in the slag cooler, thereby improving heat exchange efficiency. To further reduce losses, achieve energy conservation, improve the thermal economy of the unit, and avoid reducing the effectiveness of waste heat utilization, the device includes:

[0020] The condensate inlet control module is used to collect the first condensate temperature at the outlet condensate temperature measuring point of the low-temperature heat exchange zone when both the high-temperature heat exchange zone inlet flow regulating valve and the low-temperature heat exchange zone inlet flow regulating valve are in automatic temperature control mode. It also collects the second, third, and fourth condensate temperatures at the condensate temperature measuring points of the first, second, third, and fourth low-pressure heaters, respectively. The module calculates the condensate temperature difference between the first, second, third, and fourth condensate temperatures. It then determines the low-pressure heater with the smallest condensate temperature difference. A preset time period is set, and it is determined whether the condensate temperature difference of the low-pressure heater with the smallest difference remains the smallest within that time period. If so, the module opens the outlet shut-off valve from the low-temperature heat exchange zone to the outlet of the low-pressure heater with the smallest difference; and closes the outlet shut-off valves from the low-temperature heat exchange zone to the other two low-pressure heaters.

[0021] The water inlet control module is used to collect the first water supply temperature at the outlet water supply temperature measuring point of the high-temperature heat exchange zone when both the high-temperature heat exchange zone inlet water flow regulating valve and the low-temperature heat exchange zone inlet water flow regulating valve are in automatic temperature control mode; collect the second water supply temperature at the first high-pressure heater's water supply temperature measuring point, the third water supply temperature at the second high-pressure heater's water supply temperature measuring point, and the fourth water supply temperature at the third high-pressure heater's water supply temperature measuring point; calculate the water supply temperature difference between the first water supply temperature and the second, third, and fourth water supply temperatures respectively; determine the high-pressure heater with the smallest water supply temperature difference; set a preset time period and determine whether the water supply temperature difference of the high-pressure heater with the smallest water supply temperature difference is still the smallest within the preset time period. If so, open the shut-off valve from the high-temperature heat exchange zone outlet to the high-pressure heater outlet with the smallest temperature difference; and close the shut-off valves from the high-temperature heat exchange zone outlet to the other two high-pressure heater outlets.

[0022] This invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the control method of the above-mentioned waste heat recovery system for the slag cooler.

[0023] This invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the control method of the above-described waste heat recovery system for the slag cooler.

[0024] This invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the control method of the above-mentioned waste heat recovery system for the slag cooler.

[0025] In this embodiment of the invention, the waste heat recovery system for the slag cooler includes: a slag cooler, which is divided into a high-temperature heat exchange zone and a low-temperature heat exchange zone; a high-temperature heat exchange zone inlet water flow regulating valve for regulating the inlet water flow of the high-temperature heat exchange zone; a low-temperature heat exchange zone inlet water flow regulating valve for regulating the inlet water flow of the low-temperature heat exchange zone; a high-pressure heater regeneration system, including a first high-pressure heater, a second high-pressure heater, and a third high-pressure heater, for heating the cooling water output from the outlet of the high-temperature heat exchange zone; a low-pressure heater regeneration system, including a first low-pressure heater, a second low-pressure heater, and a third low-pressure heater, for heating the cooling water output from the outlet of the low-temperature heat exchange zone; and a connection between the high-temperature heat exchange zone outlet water and the outlet of the first high-pressure heater. The system includes a stop valve, a stop valve for water outlet from the high-temperature heat exchange zone to the outlet of the second high-pressure heater, and a stop valve for water outlet from the high-temperature heat exchange zone to the outlet of the third high-pressure heater, used to control the water outlet from the high-temperature heat exchange zone to any high-pressure heater; a stop valve for water outlet from the low-temperature heat exchange zone to the outlet of the first low-pressure heater, a stop valve for water outlet from the low-temperature heat exchange zone to the outlet of the second low-pressure heater, and a stop valve for water outlet from the low-temperature heat exchange zone to the outlet of the third low-pressure heater, used to control the water outlet from the low-temperature heat exchange zone to any low-pressure heater; a boiler ash discharge gate connected to the ash inlet of the high-temperature heat exchange zone of the ash cooler; and an ash bin connected to the ash discharge outlet of the low-temperature heat exchange zone of the ash cooler. The boiler ash discharged from the boiler ash discharge gate passes through the high-temperature heat exchange zone and the low-temperature heat exchange zone sequentially to release heat before being sent to the ash bin. Compared to existing waste heat recovery systems for slag coolers that utilize low-pressure heater reheat systems, this system divides the slag cooler into high-temperature and low-temperature heat exchange zones. Cooling water enters each zone separately to absorb heat, enabling tiered utilization of heat within the slag cooler. This reduces the temperature difference between water and slag within the cooler, thus improving heat exchange efficiency. The loss is further reduced, and the high-parameter high-pressure steam extraction and low-parameter low-pressure steam extraction are eliminated, which improves the thermal economy of the unit. At the same time, by setting a shut-off valve from the outlet of the high-temperature heat exchange zone to the outlet of each high-pressure heater to control the outlet of the high-temperature heat exchange zone to the high-pressure heater, and setting a shut-off valve from the outlet of the low-temperature heat exchange zone to the outlet of each low-pressure heater to control the outlet of the low-temperature heat exchange zone to the low-pressure heater, the effect of waste heat utilization can be avoided.

[0026] In this embodiment of the invention, the control method of the waste heat recovery system of the slag cooler involves the following steps: When the inlet water flow regulating valve of the high-temperature heat exchange zone is in automatic temperature control mode, and the inlet water flow regulating valve of the low-temperature heat exchange zone is in automatic temperature control mode, the first condensate temperature at the outlet condensate temperature measuring point of the low-temperature heat exchange zone is collected; the second condensate temperature, the third condensate temperature, and the fourth condensate temperature at the condensate temperature measuring point of the first low-pressure heater are collected; the condensate temperature difference between the first condensate temperature and the second, third, and fourth condensate temperatures are calculated respectively; the low-pressure heater with the smallest condensate temperature difference is determined; a preset time period is set, and it is determined whether the condensate temperature difference of the low-pressure heater with the smallest condensate temperature difference is still the smallest within the preset time period. If so, the low-temperature heat exchanger is activated. The hot zone outlet water flows to the outlet shut-off valve of the low-pressure heater with the smallest difference; the outlet water from the low-temperature heat exchange zone flows to the outlet shut-off valves of the other two low-pressure heaters; the first feedwater temperature is collected at the outlet feedwater temperature measuring point of the high-temperature heat exchange zone; the second feedwater temperature is collected at the feedwater temperature measuring point of the first high-pressure heater, the third feedwater temperature is collected at the feedwater temperature measuring point of the second high-pressure heater, and the fourth feedwater temperature is collected at the feedwater temperature measuring point of the third high-pressure heater; the differences between the first feedwater temperature and the second, third, and fourth feedwater temperatures are calculated respectively; the high-pressure heater with the smallest feedwater difference is determined; a preset time period is set, and it is determined whether the feedwater difference of the high-pressure heater with the smallest feedwater difference is still the smallest within the preset time period. If so, the outlet water from the high-temperature heat exchange zone flows to the outlet shut-off valve of the high-pressure heater with the smallest difference; the outlet water from the high-temperature heat exchange zone flows to the outlet shut-off valves of the other two high-pressure heaters. In this way, when the cooling water enters the high-temperature heat exchange zone and the low-temperature heat exchange zone to absorb heat, the outlet water temperature of the slag cooler can be reasonably matched with the return water inlet temperature according to the principle of minimum temperature difference, so as to avoid reducing the effect of waste heat utilization. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0028] Figure 1 This is a structural diagram of a waste heat recovery system for a slag cooler provided in an embodiment of the present invention;

[0029] Figure 2 This is a flowchart of a control method for a waste heat recovery system for a slag cooler provided in an embodiment of the present invention;

[0030] Figure 3This is a flowchart of the startup control process method provided in the embodiments of the present invention;

[0031] Figure 4 This is a schematic diagram of a control device for a waste heat recovery system of a slag cooler according to an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of a control device for a waste heat recovery system of a slag cooler, as described in another embodiment of the present invention.

[0033] Figure 6 This is a schematic diagram of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0035] In the description of this specification, the terms "comprising," "including," "having," and "containing" are open-ended terms, meaning that they include but are not limited to. The terms "an embodiment," "a specific embodiment," "some embodiments," and "for example," etc., refer to specific features, structures, or characteristics described in connection with that embodiment or example that are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. The order of steps involved in the various embodiments is used to illustrate the implementation of this application, and the order of steps is not limited and can be adjusted appropriately as needed.

[0036] Research has revealed that the current common method for recovering heat from ash discharge in circulating fluidized bed boilers involves adding a ash cooler. Specifically, this utilizes the condensate from the low-pressure heater's regenerative system to absorb the waste heat from the boiler ash discharge, and then the heated condensate returns to the low-pressure heater's regenerative system. However, based on empirical data, the ash temperature at the ash cooler inlet is approximately 850℃, while the ash temperature at the outlet is approximately 150℃. The inlet water temperature of the ash cooler is 48℃, and the outlet water temperature is 98℃. This indicates a significant temperature difference between the ash and water temperatures, resulting in substantial heat exchange issues. Despite the loss, there is still significant potential for energy saving; moreover, in actual operation, if the return water position of the slag cooler is improper and the return water temperature is lower than the main condensate temperature at the inlet point, it will actually reduce the efficiency of waste heat utilization.

[0037] In response to the above research, embodiments of the present invention provide a waste heat recovery system for a slag cooler, a control method for the system, and an apparatus, which can reduce the heat exchange temperature difference between water and slag in the slag cooler, thereby improving heat exchange efficiency. This further reduces energy consumption, achieves energy-saving goals, improves the thermal economy of the unit, and avoids reducing the effectiveness of waste heat utilization.

[0038] like Figure 1 The diagram shown is a structural diagram of a waste heat recovery system for a slag cooler provided in an embodiment of the present invention. The system may include:

[0039] The slag cooler 1 is divided into a high-temperature heat exchange zone and a low-temperature heat exchange zone.

[0040] High-temperature heat exchange zone inlet water flow regulating valve 2 is used to regulate the inlet water flow of the high-temperature heat exchange zone;

[0041] Low-temperature heat exchange zone inlet water flow regulating valve 3 is used to regulate the inlet water flow of the low-temperature heat exchange zone;

[0042] The high-pressure heater regenerative system includes a first high-pressure heater 10, a second high-pressure heater 11 and a third high-pressure heater 12, which are used to heat the cooling water output from the outlet of the high-temperature heat exchange zone.

[0043] The low-pressure heater regenerative system includes a first low-pressure heater 13, a second low-pressure heater 14 and a third low-pressure heater 15, which are used to heat the cooling water output from the outlet of the low-temperature heat exchange zone.

[0044] The high-temperature heat exchange zone outlet water to the first high-pressure heater outlet shut-off valve 4, the high-temperature heat exchange zone outlet water to the second high-pressure heater outlet shut-off valve 5, and the high-temperature heat exchange zone outlet water to the third high-pressure heater outlet shut-off valve 6 are used to control the inlet point of the high-temperature heat exchange zone outlet water to any high-pressure heater.

[0045] The low-temperature heat exchange zone outlet water to the first low-pressure heater outlet shut-off valve 7, the low-temperature heat exchange zone outlet water to the second low-pressure heater outlet shut-off valve 8, and the low-temperature heat exchange zone outlet water to the third low-pressure heater outlet shut-off valve 9 are used to control the inlet point of the low-temperature heat exchange zone outlet water to any low-pressure heater.

[0046] The boiler ash discharge door 19 is connected to the ash inlet of the high-temperature heat exchange zone of the ash cooler 1;

[0047] The slag bin is connected to the slag discharge outlet of the low-temperature heat exchange zone of the slag cooler 1;

[0048] Among them, the boiler slag discharged from the boiler slag discharge gate passes through the high-temperature heat exchange zone and the low-temperature heat exchange zone in sequence to release heat before being sent to the slag bin.

[0049] In one embodiment, such as Figure 1As shown, the system may also include: a condensate pump 18, which is connected to the low-temperature heat exchange zone and is used to output condensate;

[0050] The cooling water in the low-temperature heat exchange zone is condensate pumped from the condensate pump. The condensate pumped from the condensate pump enters the low-temperature heat exchange zone through the inlet flow regulating valve to absorb heat, and then returns to the low-pressure heater regeneration system through the condensate outlet of the low-temperature heat exchange zone.

[0051] In one embodiment, such as Figure 1 As shown, the system may also include a deaerator 16 for deoxygenating the condensate.

[0052] In one embodiment, the low-pressure heater regenerative system is provided with multiple condensate inlet points for the condensate outlets of the low-temperature heat exchange zones. The condensate inlet points for the condensate outlets of the low-temperature heat exchange zones include a first low-pressure heater condensate inlet point, a second low-pressure heater condensate inlet point, and a third low-pressure heater condensate inlet point.

[0053] The condensate outlet of the low-temperature heat exchange zone is connected to the outlet valve of the first low-pressure heater via the water outlet of the low-temperature heat exchange zone, and is connected to the condensate inlet of the first low-pressure heater.

[0054] The condensate outlet of the low-temperature heat exchange zone is connected to the outlet shut-off valve of the second low-pressure heater via the water outlet of the low-temperature heat exchange zone, and is connected to the condensate inlet of the second low-pressure heater.

[0055] The condensate outlet of the low-temperature heat exchange zone is connected to the outlet shut-off valve of the third low-pressure heater via the water outlet of the low-temperature heat exchange zone, and is connected to the condensate inlet of the third low-pressure heater.

[0056] In practice, the outlet shut-off valve of the low-temperature heat exchange zone to each low-pressure heater is used to control the condensate output from the condensate outlet of the low-temperature heat exchange zone to flow into the condensate inlet of any low-pressure heater. When the outlet shut-off valve of the low-temperature heat exchange zone to any low-pressure heater is opened, the condensate output from the condensate outlet of the low-temperature heat exchange zone flows into the condensate inlet of that low-pressure heater.

[0057] In one embodiment, condensate temperature measuring points are respectively set at the condensate inlet points of the first low-pressure heater, the second low-pressure heater, and the third low-pressure heater.

[0058] A condensate temperature measuring point is installed at the condensate outlet of the low-temperature heat exchange zone; a condensate temperature measuring point is installed at the condensate inlet of the low-temperature heat exchange zone.

[0059] In specific implementation, such as Figure 1As shown, T7 is the condensate temperature measuring point at the condensate inlet of the third low-pressure heater; T8 is the condensate temperature measuring point at the condensate inlet of the second low-pressure heater; and T9 is the condensate temperature measuring point at the condensate inlet of the first low-pressure heater.

[0060] In specific implementation, such as Figure 1 As shown, T3 is the condensate temperature measuring point at the outlet of the low-temperature heat exchange zone; T5 is the condensate temperature measuring point at the inlet of the low-temperature heat exchange zone.

[0061] In one embodiment, the system may further include: a water supply pump 17, which is connected to the high-temperature heat exchange zone and is used to output water supply.

[0062] The cooling water in the high-temperature heat exchange zone is supplied by a water pump. The water pump supplies water to the high-temperature heat exchange zone through the inlet flow regulating valve to absorb heat, and then returns to the high-pressure heater regeneration system through the water outlet of the high-temperature heat exchange zone.

[0063] In one embodiment, the high-pressure heater regenerative system is provided with multiple feedwater inlet points from the feedwater outlets of the high-temperature heat exchange zones, including a first high-pressure heater feedwater inlet point, a second high-pressure heater feedwater inlet point, and a third high-pressure heater feedwater inlet point.

[0064] The water outlet of the high-temperature heat exchange zone is connected to the outlet valve of the first high-pressure heater via the water outlet of the high-temperature heat exchange zone, and is connected to the water inlet of the first high-pressure heater.

[0065] The water outlet of the high-temperature heat exchange zone is connected to the outlet valve of the second high-pressure heater via the water outlet of the high-temperature heat exchange zone, and is connected to the water inlet of the second high-pressure heater.

[0066] The water outlet of the high-temperature heat exchange zone is connected to the outlet valve of the third high-pressure heater via the water outlet of the high-temperature heat exchange zone, and is connected to the water inlet of the third high-pressure heater.

[0067] In practice, the water outlet valve of the high-temperature heat exchange zone to the outlet shut-off valve of each high-pressure heater is used to control the water output from the water outlet of the high-temperature heat exchange zone to flow into the water inlet of any high-pressure heater. When the water outlet valve of the high-temperature heat exchange zone to the outlet shut-off valve of any high-pressure heater is opened, the water output from the water outlet of the high-temperature heat exchange zone flows into the water inlet of that high-pressure heater.

[0068] In one embodiment, water supply temperature measuring points are respectively set at the water supply inlet points of the first high-pressure heater, the second high-pressure heater, and the third high-pressure heater;

[0069] A high-temperature heat exchange zone outlet water temperature measuring point is set at the water supply outlet of the high-temperature heat exchange zone; a high-temperature heat exchange zone inlet water temperature measuring point is set at the water supply inlet of the high-temperature heat exchange zone.

[0070] In specific implementation, such as Figure 1 As shown, T10 is the feedwater temperature measuring point at the feedwater inlet of the first high-pressure heater; T11 is the feedwater temperature measuring point at the feedwater inlet of the second high-pressure heater; and T12 is the feedwater temperature measuring point at the feedwater inlet of the third high-pressure heater.

[0071] In specific implementation, such as Figure 1 As shown, T4 is the outlet feedwater temperature measuring point of the high-temperature heat exchange zone; T6 is the inlet feedwater temperature measuring point of the high-temperature heat exchange zone.

[0072] In one embodiment, a high-temperature heat exchange zone outlet slag temperature measuring point is provided at the slag discharge outlet of the high-temperature heat exchange zone; and a low-temperature heat exchange zone outlet slag temperature measuring point is provided at the slag discharge outlet of the low-temperature heat exchange zone.

[0073] In specific implementation, such as Figure 1 As shown, T1 is the slag temperature measuring point at the outlet of the high-temperature heat exchange zone; T2 is the slag temperature measuring point at the outlet of the low-temperature heat exchange zone.

[0074] In this way, the aforementioned waste heat recovery system for the slag cooler, by dividing the slag cooler into a high-temperature heat exchange zone and a low-temperature heat exchange zone, allows the feedwater from the feedwater pump outlet to enter the high-temperature heat exchange zone of the slag cooler to absorb heat, while the condensate from the condensate pump outlet enters the low-temperature heat exchange zone of the slag cooler to absorb heat. This setup achieves cascaded utilization of heat within the slag cooler, reducing the temperature difference between the water and slag within the slag cooler, and improving heat exchange efficiency. The losses were further reduced; the high-parameter high-pressure extraction steam and low-parameter low-pressure extraction steam were further eliminated, improving the thermal economy of the unit; at the same time, the return water inlet position of the slag cooler was optimized. By setting a shut-off valve from the outlet of the high-temperature heat exchange zone to the outlet of each high-pressure heater, the inlet point of the high-temperature heat exchange zone water to any high-pressure heater was controlled; similarly, a shut-off valve from the outlet of the low-temperature heat exchange zone to the outlet of each low-pressure heater was set, controlling the inlet point of the low-temperature heat exchange zone water to any low-pressure heater. In this way, the inlet point of the low-temperature heat exchange zone outlet and the low-pressure heater regeneration system, as well as the inlet point of the high-temperature heat exchange zone outlet water pipe and the high-pressure heater regeneration system, can be optimized, further realizing the reasonable matching of the slag cooler outlet and the return water inlet point, and avoiding the reduction of the waste heat utilization effect.

[0075] This invention also provides a control method for a waste heat recovery system of a slag cooler, used to control the reasonable matching of the outlet water temperature of the slag cooler and the return water inlet temperature; such as Figure 2 As shown, the control method may include:

[0076] Step 201: When the inlet water flow regulating valve of the high-temperature heat exchange zone is in automatic temperature control mode, and the inlet water flow regulating valve of the low-temperature heat exchange zone is in automatic temperature control mode, the first condensate temperature at the outlet condensate temperature measuring point of the low-temperature heat exchange zone is collected; the second condensate temperature at the condensate temperature measuring point of the first low-pressure heater, the third condensate temperature at the condensate temperature measuring point of the second low-pressure heater, and the fourth condensate temperature at the condensate temperature measuring point of the third low-pressure heater are collected; the condensate temperature difference between the first condensate temperature and the second, third, and fourth condensate temperatures are calculated respectively; the low-pressure heater with the smallest condensate temperature difference is determined; a preset time period is set, and it is determined whether the condensate temperature difference of the low-pressure heater with the smallest condensate temperature difference is still the smallest within the preset time period. If so, the outlet water from the low-temperature heat exchange zone to the outlet shut-off valve of the low-pressure heater with the smallest temperature difference is opened; the outlet water from the low-temperature heat exchange zone to the outlet shut-off valves of the other two low-pressure heaters is closed.

[0077] Step 202: When the inlet water flow regulating valve of the high-temperature heat exchange zone is in automatic temperature control mode, and the inlet water flow regulating valve of the low-temperature heat exchange zone is in automatic temperature control mode, the first feedwater temperature at the outlet feedwater temperature measuring point of the high-temperature heat exchange zone is collected; the second feedwater temperature at the feedwater temperature measuring point of the first high-pressure heater, the third feedwater temperature at the feedwater temperature measuring point of the second high-pressure heater, and the fourth feedwater temperature at the feedwater temperature measuring point of the third high-pressure heater are collected; the feedwater temperature difference between the first feedwater temperature and the second, third, and fourth feedwater temperatures are calculated respectively; the high-pressure heater with the smallest feedwater temperature difference is determined; a preset time period is set, and it is determined whether the feedwater temperature difference of the high-pressure heater with the smallest feedwater temperature difference is still the smallest within the preset time period. If so, the outlet water from the high-temperature heat exchange zone to the outlet shut-off valve of the high-pressure heater with the smallest temperature difference is opened; the outlet water from the high-temperature heat exchange zone to the outlet shut-off valves of the other two high-pressure heaters is closed.

[0078] In practice, step 201 controls the location of the inlet point of the low-pressure heater regenerative system; step 202 controls the location of the inlet point of the high-pressure heater regenerative system. The order of steps 201 and 202 is not limited.

[0079] In one embodiment, before step 201 above, it is also necessary to start the waste heat recovery system of the slag cooler so that both the inlet water flow regulating valve of the high temperature heat exchange zone and the inlet water flow regulating valve of the low temperature heat exchange zone are put into automatic temperature control mode.

[0080] like Figure 3 The diagram shown is a flowchart of the method for initiating the control process, which may specifically include:

[0081] Step 301: Open the shut-off valve for the outlet water of the low-temperature heat exchange zone to the outlet of the first low-pressure heater, and close the shut-off valves for the outlet water of the low-temperature heat exchange zone to the outlet of the second low-pressure heater and the shut-off valve for the outlet water of the low-temperature heat exchange zone to the outlet of the third low-pressure heater.

[0082] Step 302: Open the inlet water flow regulating valve of the low temperature heat exchange zone to the first specified opening degree;

[0083] Step 303: Open the shut-off valve for the outlet water of the high temperature heat exchange zone to the outlet of the third high pressure heater, and close the shut-off valves for the outlet water of the high temperature heat exchange zone to the outlet of the first high pressure heater and the shut-off valve for the outlet water of the high temperature heat exchange zone to the outlet of the second high pressure heater.

[0084] Step 304: Open the inlet water flow regulating valve of the high-temperature heat exchange zone to the second specified opening degree;

[0085] Step 305: Open the boiler ash discharge door. When the ash enters the high-temperature heat exchange zone, collect the first ash temperature at the ash temperature measuring point at the outlet of the high-temperature heat exchange zone. When the first ash temperature is detected to rise to the first preset temperature, the high-temperature heat exchange zone inlet water flow regulating valve is put into the automatic control mode for the first ash temperature. When the ash enters the low-temperature heat exchange zone, collect the second ash temperature at the ash temperature measuring point at the outlet of the low-temperature heat exchange zone. When the second ash temperature is detected to rise to the second preset temperature, the low-temperature heat exchange zone inlet water flow regulating valve is put into the automatic control mode for the second ash temperature.

[0086] In specific implementation, after the cooling water is introduced, in step 301, firstly, for the low-temperature heat exchange zone of the slag cooler, preferably, refer to Figure 1 The valve 7, which shuts off the water outlet from the low-temperature heat exchange zone to the outlet of the first low-pressure heater, can be opened, while the valves 8, 8, 8, and 9, which shut off the water outlet from the low-temperature heat exchange zone to the outlet of the third low-pressure heater, can be closed.

[0087] In specific implementation, in step 302, the inlet water flow adjustment valve 3 of the low temperature heat exchange zone of the cold slag is opened and the opening degree is set to a certain specified degree; preferably, the opening degree of the inlet water flow adjustment valve 3 of the low temperature heat exchange zone is set to 50%.

[0088] In specific implementation, in step 303, for the high-temperature heat exchange zone of the slag cooler, preferably, the outlet valve 6 of the high-temperature heat exchange zone water to the third high-pressure heater outlet is opened, and the outlet valve 4 of the high-temperature heat exchange zone water to the first high-pressure heater outlet and the outlet valve 5 of the high-temperature heat exchange zone water to the second high-pressure heater outlet are closed.

[0089] In specific implementation, in step 304, the high-temperature heat exchange zone inlet water flow adjustment valve 2 of the cold slag is opened and the opening degree is set to a certain specified degree; preferably, the opening degree of the high-temperature heat exchange zone inlet water flow adjustment valve 2 is set to 50%.

[0090] In specific implementation, in step 305, the boiler ash discharge door is opened and the waste heat recovery system of the ash cooler is put into use. At this time, it is necessary to put the inlet water flow adjustment valve of the high temperature heat exchange zone and the inlet water flow adjustment valve of the low temperature heat exchange zone in the waste heat recovery system of the ash cooler into the automatic temperature control mode.

[0091] Specifically, it can be set that when the slag temperature (first slag temperature) measured at the slag temperature measuring point at the outlet of the high-temperature heat exchange zone rises to a preset temperature, the water inlet flow regulating valve of the high-temperature heat exchange zone will enter the automatic temperature control mode to control the temperature of the boiler slag output from the boiler slag discharge gate to the high-temperature heat exchange zone. When the slag temperature (second slag temperature) measured at the slag temperature measuring point at the outlet of the low-temperature heat exchange zone rises to another preset temperature (second preset temperature), the water inlet flow regulating valve of the low-temperature heat exchange zone will enter the automatic temperature control mode to control the temperature of the boiler slag output from the high-temperature heat exchange zone to the low-temperature heat exchange zone.

[0092] For example, when the temperature of T1 (the first slag temperature) rises to 350℃ (the first preset temperature), the water inlet flow regulating valve of the high-temperature heat exchange zone is put into automatic temperature control mode, that is, when the slag temperature at the outlet of the high-temperature heat exchange zone rises to 350 degrees, the water inlet flow regulating valve of the high-temperature heat exchange zone is put into automatic temperature control mode; when the temperature of T2 (the second slag temperature) rises to 100℃ (the second preset temperature), the water inlet flow regulating valve of the low-temperature heat exchange zone is put into automatic temperature control mode, that is, when the slag temperature at the outlet of the low-temperature heat exchange zone rises to 100 degrees, the water inlet flow regulating valve of the low-temperature heat exchange zone is put into automatic temperature control mode.

[0093] When both the inlet flow regulating valve of the high-temperature heat exchange zone and the inlet flow regulating valve of the low-temperature heat exchange zone are put into automatic temperature control mode, steps 201 and 202 are executed.

[0094] In specific implementation, in step 201, the temperature of the condensate temperature measuring point T3 at the outlet of the low-temperature heat exchange zone (first condensate temperature), the temperature of the condensate temperature measuring point T7 at the condensate inlet of the third low-pressure heater (fourth condensate temperature), the temperature of the condensate temperature measuring point T8 at the condensate inlet of the second low-pressure heater (third condensate temperature), and the temperature of the condensate temperature measuring point T9 at the condensate inlet of the first low-pressure heater (second condensate temperature) are collected.

[0095] Then, determine the relationship between the temperature differences of T3 and T7, T8, and T9:

[0096] A=|T7-T3|, B=|T8-T3|, C=|T9-T3|;

[0097] A is the absolute value of the temperature difference between T3 and T7;

[0098] B is the absolute value of the temperature difference between T3 and T8;

[0099] C is the absolute value of the temperature difference between T3 and T7.

[0100] Then, take the function F1 = min{A,B,C};

[0101] This function selects the minimum value from A, B, and C. This minimum value represents the outlet water temperature of the low-temperature heat exchange zone that is closest to the outlet water temperature of the corresponding low-pressure heater. Simultaneously, to avoid factors such as operational disturbances, a preset delay time period (preset time period) is used. If the minimum value remains unchanged within this delay time period, the shut-off valve from the low-temperature heat exchange zone outlet water to the outlet of the low-pressure heater corresponding to the minimum value is opened; the shut-off valves from the low-temperature heat exchange zone outlet water to the outlets of the other low-pressure heaters are closed.

[0102] For example, if F1 = A, preferably, the preset delay time is 10 minutes; if the minimum does not change during this delay time, the valve for shutting off the outlet water from the low-temperature heat exchange zone to the outlet of the third low-pressure heater is opened; and the valves for shutting off the outlet water from the low-temperature heat exchange zone to the outlet of the first low-pressure heater and the valve for shutting off the outlet water from the low-temperature heat exchange zone to the outlet of the second low-pressure heater are closed.

[0103] Similarly, if F1 = B and the delay is 10 minutes, then open the shut-off valve from the outlet of the low-temperature heat exchange zone to the outlet of the second low-pressure heater; close the shut-off valves from the outlet of the low-temperature heat exchange zone to the outlet of the first low-pressure heater and from the outlet of the low-temperature heat exchange zone to the outlet of the third low-pressure heater.

[0104] Similarly, if F1 = C and the delay is 10 minutes, then the valve for shutting off the water outlet from the low-temperature heat exchange zone to the outlet of the first low-pressure heater will be opened; and the valves for shutting off the water outlet from the low-temperature heat exchange zone to the outlet of the third low-pressure heater and the valves for shutting off the water outlet from the low-temperature heat exchange zone of the slag cooler to the outlet of the second low-pressure heater will be closed.

[0105] In specific implementation, in step 202, the temperature of the feedwater temperature measuring point T4 at the outlet of the high-temperature heat exchange zone (first feedwater temperature), the temperature of the feedwater temperature measuring point T10 at the feedwater inlet of the first high-pressure heater (fourth feedwater temperature), the temperature of the feedwater temperature measuring point T11 at the feedwater inlet of the second high-pressure heater (third feedwater temperature), and the temperature of the feedwater temperature measuring point T12 at the feedwater inlet of the third high-pressure heater (second feedwater temperature) are collected.

[0106] Then, determine the temperature difference relationship between T4 and T10, T11, and T12:

[0107] D=|T10-T4|, E=|T11-T4|, F=|T12-T4|;

[0108] D is the absolute value of the temperature difference between T4 and T10;

[0109] E is the absolute value of the temperature difference between T4 and T11;

[0110] F is the absolute value of the temperature difference between T4 and T12.

[0111] Then, take the function F2 = min{D,E,F};

[0112] This function selects the minimum value from D, E, and F. This minimum value indicates that the outlet water temperature of the high-temperature heat exchange zone is closest to the outlet water temperature of the corresponding high-pressure heater. Simultaneously, to avoid factors such as operational disturbances, a preset delay time period (preset time period) is used. If the minimum value remains unchanged within this delay time period, the shut-off valve from the high-temperature heat exchange zone outlet to the high-pressure heater outlet corresponding to the minimum value is opened; the shut-off valves from the high-temperature heat exchange zone outlet to the outlets of the other high-pressure heaters are closed.

[0113] For example, if F2 = D, preferably, the preset delay time is 10 minutes; if the minimum does not change during this delay time, the high-temperature heat exchange zone outlet water to the first high-pressure heater outlet shut-off valve is opened; the high-temperature heat exchange zone outlet water to the second high-pressure heater outlet shut-off valve and the high-temperature heat exchange zone outlet water to the third high-pressure heater outlet shut-off valve are closed.

[0114] Similarly, if F2 = E and the delay is 10 minutes, then open the shut-off valve from the outlet of the high-temperature heat exchange zone to the outlet of the second high-pressure heater; close the shut-off valves from the outlet of the high-temperature heat exchange zone to the outlet of the first high-pressure heater and from the outlet of the high-temperature heat exchange zone to the outlet of the third high-pressure heater.

[0115] Similarly, if F2 = F and the delay is 10 minutes, then open the shut-off valve from the outlet of the high-temperature heat exchange zone to the outlet of the third high-pressure heater; close the shut-off valve from the outlet of the high-temperature heat exchange zone to the outlet of the second high-pressure heater and the shut-off valve from the outlet of the high-temperature heat exchange zone to the outlet of the first high-pressure heater.

[0116] In this way, through the control method of the above-mentioned waste heat recovery system of the slag cooler, when the feedwater from the feedwater pump outlet enters the high-temperature heat exchange zone of the slag cooler to absorb heat, and the condensate from the condensate pump outlet enters the low-temperature heat exchange zone of the slag cooler to absorb heat, the connection point between the outlet water pipe of the low-temperature heat exchange zone and the low-temperature heat recovery system and the connection point between the outlet water pipe of the high-temperature heat exchange zone and the high-temperature heat recovery system are adjusted and optimized according to the principle of minimum temperature difference. This achieves a reasonable match between the outlet water temperature of the slag cooler and the return water connection point, thus avoiding a reduction in the effect of waste heat utilization.

[0117] This invention also provides a control device for a waste heat recovery system of a slag cooler, as described in the following embodiments. Since the principle by which this device solves the problem is similar to the control method of the waste heat recovery system of the slag cooler, the implementation of this device can refer to the implementation of the control method of the waste heat recovery system of the slag cooler, and will not be repeated here.

[0118] like Figure 4 The diagram shown is a schematic of a control device for a waste heat recovery system for a slag cooler according to an embodiment of the present invention. This device may include:

[0119] The condensate inlet control module 401 is used to collect the first condensate temperature at the outlet condensate temperature measuring point of the low-temperature heat exchange zone when both the high-temperature heat exchange zone inlet flow regulating valve and the low-temperature heat exchange zone inlet flow regulating valve are in automatic temperature control mode; collect the second condensate temperature at the condensate temperature measuring point of the first low-pressure heater, the third condensate temperature at the condensate temperature measuring point of the second low-pressure heater, and the fourth condensate temperature at the condensate temperature measuring point of the third low-pressure heater; calculate the condensate temperature difference between the first condensate temperature and the second, third, and fourth condensate temperatures respectively; determine the low-pressure heater with the smallest condensate temperature difference; set a preset time period, and determine whether the condensate temperature difference of the low-pressure heater with the smallest condensate temperature difference is still the smallest within the preset time period. If so, open the outlet shut-off valve of the low-temperature heat exchange zone to the outlet shut-off valve of the low-pressure heater with the smallest temperature difference; and close the outlet shut-off valves of the low-temperature heat exchange zone to the outlet of the other two low-pressure heaters.

[0120] The water inlet control module 402 is used to collect the first water supply temperature at the outlet water supply temperature measuring point of the high-temperature heat exchange zone when the inlet water flow regulating valve of the high-temperature heat exchange zone is in automatic temperature control mode and the inlet water flow regulating valve of the low-temperature heat exchange zone is in automatic temperature control mode; collect the second water supply temperature at the water supply temperature measuring point of the first high-pressure heater, the third water supply temperature at the water supply temperature measuring point of the second high-pressure heater, and the fourth water supply temperature at the water supply temperature measuring point of the third high-pressure heater; calculate the water supply temperature difference between the first water supply temperature and the second, third, and fourth water supply temperatures respectively; determine the high-pressure heater with the smallest water supply temperature difference; set a preset time period and determine whether the water supply temperature difference of the high-pressure heater with the smallest water supply temperature difference is still the smallest within the preset time period. If so, open the outlet shut-off valve of the high-temperature heat exchange zone to the outlet shut-off valve of the high-pressure heater with the smallest water supply temperature difference; and close the outlet shut-off valve of the high-temperature heat exchange zone to the outlet shut-off valves of the other two high-pressure heaters.

[0121] In one embodiment, such as Figure 5 As shown, the above-mentioned control device also includes a start module 501, which can be used for:

[0122] Open the valve to the outlet of the first low-pressure heater and close the valves to the outlet of the second low-pressure heater and the outlet of the third low-pressure heater.

[0123] Open the inlet water flow regulating valve of the low-temperature heat exchange zone to the first specified opening degree;

[0124] Open the shut-off valve for the outlet water of the high temperature heat exchange zone to the outlet of the third high pressure heater, and close the shut-off valves for the outlet water of the high temperature heat exchange zone to the outlet of the first high pressure heater and the shut-off valves for the outlet water of the high temperature heat exchange zone to the outlet of the second high pressure heater.

[0125] Open the inlet water flow regulating valve of the high-temperature heat exchange zone to the second specified opening degree;

[0126] With the boiler ash discharge door open, when the ash enters the high-temperature heat exchange zone, the first ash temperature is collected at the ash temperature measuring point at the outlet of the high-temperature heat exchange zone. When the first ash temperature is detected to rise to the first preset temperature, the inlet water flow regulating valve of the high-temperature heat exchange zone is put into the automatic control mode for the first ash temperature. When the ash enters the low-temperature heat exchange zone, the second ash temperature is collected at the ash temperature measuring point at the outlet of the low-temperature heat exchange zone. When the second ash temperature is detected to rise to the second preset temperature, the inlet water flow regulating valve of the low-temperature heat exchange zone is put into the automatic control mode for the second ash temperature.

[0127] This invention also provides a computer device. Figure 6 This is a schematic diagram of a computer device in an embodiment of the present invention. The computer device 600 includes a memory 610, a processor 620, and a computer program 630 stored in the memory 610 and executable on the processor 620. When the processor 620 executes the computer program 630, it implements the control method of the above-mentioned waste heat recovery system of the slag cooler.

[0128] This invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the control method of the above-described waste heat recovery system for the slag cooler.

[0129] This invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the control method of the above-mentioned waste heat recovery system for the slag cooler.

[0130] In this embodiment of the invention, the waste heat recovery system for the slag cooler includes: a slag cooler, which is divided into a high-temperature heat exchange zone and a low-temperature heat exchange zone; a high-temperature heat exchange zone inlet water flow regulating valve for regulating the inlet water flow of the high-temperature heat exchange zone; a low-temperature heat exchange zone inlet water flow regulating valve for regulating the inlet water flow of the low-temperature heat exchange zone; a high-pressure heater reheating system, including a first high-pressure heater, a second high-pressure heater, and a third high-pressure heater, for heating the cooling water output from the outlet of the high-temperature heat exchange zone; a low-pressure heater reheating system, including a first low-pressure heater, a second low-pressure heater, and a third low-pressure heater, for heating the cooling water output from the outlet of the low-temperature heat exchange zone; and a high-pressure heater outlet valve for the high-temperature heat exchange zone outlet water to the first high-pressure heater outlet shut-off valve. The outlet valves for the high-temperature heat exchange zone and the second high-pressure heater, and the third high-pressure heater, are used to control the inlet points of the high-temperature heat exchange zone water to any high-pressure heater. Similarly, the outlet valves for the low-temperature heat exchange zone and the first, second, and third low-pressure heaters are used to control the inlet points of the low-temperature heat exchange zone water to any low-pressure heater. A boiler ash discharge gate is connected to the ash inlet of the high-temperature heat exchange zone of the ash cooler. A ash bin is connected to the ash discharge outlet of the low-temperature heat exchange zone of the ash cooler. The boiler ash discharged through the boiler ash discharge gate passes through the high-temperature and low-temperature heat exchange zones sequentially to release heat before being sent to the ash bin. Compared to existing waste heat recovery systems for slag coolers that utilize low-pressure heater reheat systems, this system divides the slag cooler into high-temperature and low-temperature heat exchange zones. Cooling water enters each zone separately to absorb heat, enabling tiered utilization of heat within the slag cooler. This reduces the temperature difference between water and slag within the cooler, thus improving heat exchange efficiency. The loss is further reduced, and the high-parameter high-pressure steam extraction and low-parameter low-pressure steam extraction are eliminated, which improves the thermal economy of the unit. At the same time, by setting a shut-off valve from the outlet of the high-temperature heat exchange zone to the outlet of each high-pressure heater to control the outlet of the high-temperature heat exchange zone to the high-pressure heater, and setting a shut-off valve from the outlet of the low-temperature heat exchange zone to the outlet of each low-pressure heater to control the outlet of the low-temperature heat exchange zone to the low-pressure heater, the effect of waste heat utilization can be avoided.

[0131] In this embodiment of the invention, the control method of the waste heat recovery system of the slag cooler involves the following steps: When the inlet water flow regulating valve of the high-temperature heat exchange zone is in automatic temperature control mode, and the inlet water flow regulating valve of the low-temperature heat exchange zone is in automatic temperature control mode, the first condensate temperature at the outlet condensate temperature measuring point of the low-temperature heat exchange zone is collected; the second condensate temperature, the third condensate temperature, and the fourth condensate temperature at the condensate temperature measuring point of the first low-pressure heater are collected; the condensate temperature difference between the first condensate temperature and the second, third, and fourth condensate temperatures are calculated respectively; the low-pressure heater with the smallest condensate temperature difference is determined; a preset time period is set, and it is determined whether the condensate temperature difference of the low-pressure heater with the smallest condensate temperature difference remains the smallest within the preset time period. If so, the low-temperature heat exchange is activated. The system operates as follows: 1. The outlet water from the low-temperature heat exchange zone is connected to the outlet valve of the low-pressure heater with the smallest temperature difference. 2. The outlet water from the low-temperature heat exchange zone is closed to the outlet valves of the other two low-pressure heaters. 3. The first feedwater temperature is collected at the outlet feedwater temperature measuring point of the high-temperature heat exchange zone. 4. The second, third, and fourth feedwater temperatures are collected at the feedwater temperature measuring points of the first, second, third, and fourth high-pressure heaters, respectively. 5. The feedwater temperature difference between the first, second, third, and fourth feedwater temperatures is calculated. 6. The high-pressure heater with the smallest feedwater temperature difference is determined. 7. A preset time period is set to determine if the feedwater temperature difference of the high-pressure heater with the smallest difference remains the smallest within the preset time period. If so, the outlet water from the high-temperature heat exchange zone is opened to the outlet valve of the high-pressure heater with the smallest temperature difference. 8. The outlet water from the high-temperature heat exchange zone is closed to the outlet valves of the other two high-pressure heaters. In this way, when the cooling water enters the high-temperature heat exchange zone and the low-temperature heat exchange zone to absorb heat, the outlet water temperature of the slag cooler can be reasonably matched with the return water inlet temperature according to the principle of minimum temperature difference, so as to avoid reducing the effect of waste heat utilization.

[0132] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0133] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0134] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0135] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0136] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A waste heat recovery system for a slag cooler, characterized in that, include: A slag cooler, which is divided into a high-temperature heat exchange zone and a low-temperature heat exchange zone; The inlet water flow regulating valve for the high-temperature heat exchange zone is used to regulate the inlet water flow for the high-temperature heat exchange zone. The inlet water flow regulating valve for the low-temperature heat exchange zone is used to regulate the inlet water flow for the low-temperature heat exchange zone. The high-pressure heater regenerative system includes a first high-pressure heater, a second high-pressure heater, and a third high-pressure heater, used to heat the cooling water output from the outlet of the high-temperature heat exchange zone; The low-pressure heater regenerative system includes a first low-pressure heater, a second low-pressure heater, and a third low-pressure heater, which are used to heat the cooling water output from the outlet of the low-temperature heat exchange zone. The outlet valves for the high-temperature heat exchange zone water to the first high-pressure heater, the outlet valves for the high-temperature heat exchange zone water to the second high-pressure heater, and the outlet valves for the high-temperature heat exchange zone water to the third high-pressure heater are used to control the inlet point of the high-temperature heat exchange zone water to any of the high-pressure heaters. The outlet valves for the low-temperature heat exchange zone water to the first low-pressure heater, the outlet valves for the second low-pressure heater, and the outlet valves for the third low-pressure heater are used to control the inlet point of the low-temperature heat exchange zone water to any low-pressure heater. The boiler ash discharge door is connected to the ash inlet of the high-temperature heat exchange zone of the ash cooler. The slag bin is connected to the slag discharge outlet of the low-temperature heat exchange zone of the slag cooler. Among them, the boiler slag discharged from the boiler slag discharge gate passes through the high-temperature heat exchange zone and the low-temperature heat exchange zone in sequence to release heat before being sent to the slag bin.

2. The system as described in claim 1, characterized in that, Also includes: Condensate pump, connected to the low-temperature heat exchange zone, is used to output condensate; The cooling water in the low-temperature heat exchange zone is condensate pumped from the condensate pump. The condensate pumped from the condensate pump enters the low-temperature heat exchange zone through the inlet flow regulating valve to absorb heat, and then returns to the low-pressure heater regeneration system through the condensate outlet of the low-temperature heat exchange zone.

3. The system as described in claim 2, characterized in that, The low-pressure heater regenerative system is provided with multiple condensate inlet points for the condensate outlets of the low-temperature heat exchange zones. The condensate inlet points for the condensate outlets of the low-temperature heat exchange zones include the first low-pressure heater condensate inlet point, the second low-pressure heater condensate inlet point, and the third low-pressure heater condensate inlet point. The condensate outlet of the low-temperature heat exchange zone is connected to the outlet valve of the first low-pressure heater via the water outlet of the low-temperature heat exchange zone, and is connected to the condensate inlet of the first low-pressure heater. The condensate outlet of the low-temperature heat exchange zone is connected to the outlet shut-off valve of the second low-pressure heater via the water outlet of the low-temperature heat exchange zone, and is connected to the condensate inlet of the second low-pressure heater. The condensate outlet of the low-temperature heat exchange zone is connected to the outlet shut-off valve of the third low-pressure heater via the water outlet of the low-temperature heat exchange zone, and is connected to the condensate inlet of the third low-pressure heater.

4. The system as described in claim 3, characterized in that, Condensate temperature measuring points are respectively set at the condensate inlet points of the first low-pressure heater, the second low-pressure heater and the third low-pressure heater; A condensate temperature measuring point is installed at the condensate outlet of the low-temperature heat exchange zone; a condensate temperature measuring point is installed at the condensate inlet of the low-temperature heat exchange zone.

5. The system as described in claim 1, characterized in that, Also includes: The water supply pump is connected to the high-temperature heat exchange zone and is used to output water. The cooling water in the high-temperature heat exchange zone is supplied by a water pump. The water pump supplies water to the high-temperature heat exchange zone through the inlet flow regulating valve to absorb heat, and then returns to the high-pressure heater regeneration system through the water outlet of the high-temperature heat exchange zone.

6. The system as described in claim 5, characterized in that, The high-pressure heater regenerative system is provided with multiple feedwater inlet points from the feedwater outlets of the high-temperature heat exchange zones. The feedwater inlet points from the feedwater outlets of the high-temperature heat exchange zones include a first high-pressure heater feedwater inlet point, a second high-pressure heater feedwater inlet point, and a third high-pressure heater feedwater inlet point. The water outlet of the high-temperature heat exchange zone is connected to the outlet valve of the first high-pressure heater via the water outlet of the high-temperature heat exchange zone, and is connected to the water inlet of the first high-pressure heater. The water outlet of the high-temperature heat exchange zone is connected to the outlet valve of the second high-pressure heater via the water outlet of the high-temperature heat exchange zone, and is connected to the water inlet of the second high-pressure heater. The water outlet of the high-temperature heat exchange zone is connected to the outlet valve of the third high-pressure heater via the water outlet of the high-temperature heat exchange zone, and is connected to the water inlet of the third high-pressure heater.

7. The system as described in claim 6, characterized in that, Water temperature measuring points are respectively set at the water inlet points of the first high-pressure heater, the second high-pressure heater and the third high-pressure heater; A high-temperature heat exchange zone outlet water temperature measuring point is set at the water supply outlet of the high-temperature heat exchange zone; a high-temperature heat exchange zone inlet water temperature measuring point is set at the water supply inlet of the high-temperature heat exchange zone.

8. The system as described in claim 1, characterized in that, The slag discharge outlet of the high-temperature heat exchange zone is equipped with a slag temperature measuring point; the slag discharge outlet of the low-temperature heat exchange zone is equipped with a slag temperature measuring point.

9. A control method for a waste heat recovery system of a slag cooler, characterized in that, include: When the inlet flow regulating valve of the high-temperature heat exchange zone is put into automatic temperature control mode, and the inlet flow regulating valve of the low-temperature heat exchange zone is put into automatic temperature control mode, the first condensate temperature at the outlet condensate temperature measuring point of the low-temperature heat exchange zone is collected; the second condensate temperature at the condensate temperature measuring point of the first low-pressure heater, the third condensate temperature at the condensate temperature measuring point of the second low-pressure heater, and the fourth condensate temperature at the condensate temperature measuring point of the third low-pressure heater are collected; the condensate temperature difference between the first condensate temperature and the second, third, and fourth condensate temperatures are calculated respectively. Identify the low-pressure heater with the smallest condensate difference; Set a preset time period to determine whether the condensate difference of the low-pressure heater with the smallest condensate difference is still the smallest within the preset time period. If so, open the outlet valve of the low-temperature heat exchange zone to the outlet valve of the low-pressure heater with the smallest difference; close the outlet valve of the low-temperature heat exchange zone to the outlet valves of the other two low-pressure heaters. When the inlet water flow regulating valve of the high-temperature heat exchange zone is put into automatic temperature control mode, and the inlet water flow regulating valve of the low-temperature heat exchange zone is put into automatic temperature control mode, the first feed water temperature of the outlet feed water temperature measuring point of the high-temperature heat exchange zone is collected; the second feed water temperature of the feed water temperature measuring point of the first high-pressure heater, the third feed water temperature of the feed water temperature measuring point of the second high-pressure heater, and the fourth feed water temperature of the feed water temperature measuring point of the third high-pressure heater are collected; the feed water temperature difference between the first feed water temperature and the second, third, and fourth feed water temperatures are calculated respectively. Determine the high-pressure heater with the smallest feedwater differential; Set a preset time period and determine whether the water supply difference of the high-pressure heater with the smallest water supply difference is still the smallest within the preset time period. If so, open the outlet valve of the high-temperature heat exchange zone to the outlet valve of the high-pressure heater with the smallest water supply difference; close the outlet valve of the high-temperature heat exchange zone to the outlet valves of the other two high-pressure heaters.

10. The method as described in claim 9, characterized in that, When the inlet water flow regulating valve of the high-temperature heat exchange zone is in automatic temperature control mode, and the inlet water flow regulating valve of the low-temperature heat exchange zone is in automatic temperature control mode, the first condensate temperature at the condensate temperature measuring point at the outlet of the low-temperature heat exchange zone is collected; before collecting the second condensate temperature at the condensate temperature measuring point of the first low-pressure heater, the third condensate temperature at the condensate temperature measuring point of the second low-pressure heater, and the fourth condensate temperature at the condensate temperature measuring point of the third low-pressure heater, the following is also included: Open the valve to the outlet of the first low-pressure heater and close the valves to the outlet of the second low-pressure heater and the outlet of the third low-pressure heater. Open the inlet water flow regulating valve of the low-temperature heat exchange zone to the first specified opening degree; Open the shut-off valve for the outlet water of the high temperature heat exchange zone to the outlet of the third high pressure heater, and close the shut-off valves for the outlet water of the high temperature heat exchange zone to the outlet of the first high pressure heater and the shut-off valves for the outlet water of the high temperature heat exchange zone to the outlet of the second high pressure heater. Open the inlet water flow regulating valve of the high-temperature heat exchange zone to the second specified opening degree; With the boiler ash discharge door open, when the ash enters the high-temperature heat exchange zone, the first ash temperature is collected at the ash temperature measuring point at the outlet of the high-temperature heat exchange zone. When the first ash temperature is detected to rise to the first preset temperature, the inlet water flow regulating valve of the high-temperature heat exchange zone is put into the automatic control mode for the first ash temperature. When the ash enters the low-temperature heat exchange zone, the second ash temperature is collected at the ash temperature measuring point at the outlet of the low-temperature heat exchange zone. When the second ash temperature is detected to rise to the second preset temperature, the inlet water flow regulating valve of the low-temperature heat exchange zone is put into the automatic control mode for the second ash temperature.

11. A control device for a waste heat recovery system of a slag cooler, characterized in that, include: The condensate inlet control module is used to collect the first condensate temperature at the condensate temperature measuring point at the outlet of the low-temperature heat exchange zone when the inlet flow regulating valve of the high-temperature heat exchange zone is in automatic temperature control mode and the inlet flow regulating valve of the low-temperature heat exchange zone is in automatic temperature control mode; collect the second condensate temperature at the condensate temperature measuring point of the first low-pressure heater, the third condensate temperature at the condensate temperature measuring point of the second low-pressure heater, and the fourth condensate temperature at the condensate temperature measuring point of the third low-pressure heater; and calculate the condensate temperature difference between the first condensate temperature and the second, third, and fourth condensate temperatures respectively. Identify the low-pressure heater with the smallest condensate difference; Set a preset time period to determine whether the condensate difference of the low-pressure heater with the smallest condensate difference is still the smallest within the preset time period. If so, open the outlet valve of the low-temperature heat exchange zone to the outlet valve of the low-pressure heater with the smallest difference; close the outlet valve of the low-temperature heat exchange zone to the outlet valves of the other two low-pressure heaters. The water inlet control module is used to collect the first water supply temperature at the outlet water supply temperature measuring point of the high-temperature heat exchange zone when the inlet water flow regulating valve of the high-temperature heat exchange zone is in automatic temperature control mode and the inlet water flow regulating valve of the low-temperature heat exchange zone is in automatic temperature control mode; collect the second water supply temperature at the water supply temperature measuring point of the first high-pressure heater, the third water supply temperature at the water supply temperature measuring point of the second high-pressure heater, and the fourth water supply temperature at the water supply temperature measuring point of the third high-pressure heater; and calculate the water supply temperature difference between the first water supply temperature and the second, third, and fourth water supply temperatures respectively. Determine the high-pressure heater with the smallest feedwater differential; Set a preset time period and determine whether the water supply difference of the high-pressure heater with the smallest water supply difference is still the smallest within the preset time period. If so, open the outlet valve of the high-temperature heat exchange zone to the outlet valve of the high-pressure heater with the smallest water supply difference; close the outlet valve of the high-temperature heat exchange zone to the outlet valves of the other two high-pressure heaters.

12. The apparatus as claimed in claim 11, characterized in that, It also includes a startup module for: Open the valve to the outlet of the first low-pressure heater and close the valves to the outlet of the second low-pressure heater and the outlet of the third low-pressure heater. Open the inlet water flow regulating valve of the low-temperature heat exchange zone to the first specified opening degree; Open the shut-off valve for the outlet water of the high temperature heat exchange zone to the outlet of the third high pressure heater, and close the shut-off valves for the outlet water of the high temperature heat exchange zone to the outlet of the first high pressure heater and the shut-off valves for the outlet water of the high temperature heat exchange zone to the outlet of the second high pressure heater. Open the inlet water flow regulating valve of the high-temperature heat exchange zone to the second specified opening degree; With the boiler ash discharge door open, when the ash enters the high-temperature heat exchange zone, the first ash temperature is collected at the ash temperature measuring point at the outlet of the high-temperature heat exchange zone. When the first ash temperature is detected to rise to the first preset temperature, the inlet water flow regulating valve of the high-temperature heat exchange zone is put into the automatic control mode for the first ash temperature. When the ash enters the low-temperature heat exchange zone, the second ash temperature is collected at the ash temperature measuring point at the outlet of the low-temperature heat exchange zone. When the second ash temperature is detected to rise to the second preset temperature, the inlet water flow regulating valve of the low-temperature heat exchange zone is put into the automatic control mode for the second ash temperature.

13. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method of any one of claims 9 to 10.

14. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method of any one of claims 9 to 10.

15. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the method of any one of claims 9 to 10.

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