Waste heat recovery system and method

Abstract

This application provides a waste heat recovery system and method, relating to the field of waste heat recovery technology. The waste heat recovery system includes a cooling kiln, a first steam treatment device, a heating device, and a second steam treatment device. The cooling kiln is used to vaporize cooling water to form initial steam. The first steam treatment device is connected to the cooling kiln and is used to store the initial steam and form first-pressure steam. The heating device is connected to the first steam treatment device and is used to heat the first-pressure steam. The second steam treatment device is connected to the heating device and is used to store the heated first-pressure steam and form second-pressure steam. The pressure of the second-pressure steam is greater than that of the first-pressure steam. This application solves the problem in the prior art where large fluctuations in the temperature and flow rate of high-temperature solid materials lead to unstable steam pressure and output, achieving stable steam production and improving the system's adaptability to changes in operating conditions and operational reliability.

Description

Technical Field

[0001] This application relates to the field of waste heat recovery technology, and in particular to a waste heat recovery system and method. Background Technology

[0002] In industries such as metallurgy, chemical engineering, and building materials, high-temperature solid materials (such as steel slag, lithium roasted clinker, and ore pellets) carry a large amount of residual heat after high-temperature reactions or treatments.

[0003] To recover this portion of heat energy, equipment such as cooling kilns is typically used to cool the materials, and heat is transferred to water through a heat exchange system, converting it into steam for power generation, heating, or industrial production.

[0004] However, due to the large fluctuations in the temperature and flow rate of the incoming high-temperature solid materials, the heat load in the cooling kiln is unstable, and the existing heat exchange system cannot effectively regulate it, making it difficult to stabilize the steam pressure generated in the cooling kiln, resulting in low efficiency in steam grid connection or power generation. Summary of the Invention

[0005] This application provides a waste heat recovery system and method to solve the problem in the prior art where large fluctuations in the temperature and flow rate of high-temperature solid materials lead to unstable steam pressure and output, thereby achieving stable steam production and improving the system's adaptability to changes in operating conditions and operational reliability.

[0006] This application provides a waste heat recovery system, comprising: a cooling kiln, a first steam treatment device, a heating device, and a second steam treatment device. The cooling kiln is used to vaporize cooling water to form initial steam. The first steam treatment device is connected to the cooling kiln and is used to store the initial steam and form first pressurized steam. The heating device is connected to the first steam treatment device and is used to heat the first pressurized steam. The second steam treatment device is connected to the heating device and is used to store the heated first pressurized steam and form second pressurized steam. The pressure of the second pressurized steam is greater than the pressure of the first pressurized steam.

[0007] According to the waste heat recovery system provided in the embodiments of this application, the first steam treatment device includes: a steam drum, a kiln feed water pipe, a kiln outlet water pipe, and a cooling kiln feed water pump. The steam drum is used to store initial steam and form first pressure steam. One end of the kiln feed water pipe is connected to the inlet of the cooling kiln, and the other end is connected to the steam drum. One end of the kiln outlet water pipe is connected to the outlet of the cooling kiln, and the other end is connected to the steam drum. The cooling kiln feed water pump is located on the kiln feed water pipe and is used to pump water from the steam drum to the cooling kiln.

[0008] According to the waste heat recovery system provided in the embodiments of this application, the first steam treatment device further includes: a steam drum water supply pipe, a steam drum water supply pump, and a deaerator. The steam drum water supply pipe connects the steam drum to an external water source. The steam drum water supply pump is installed on the steam drum water supply pipe and is used to pump cooling water from the external water source to the steam drum. The deaerator is installed on the steam drum water supply pipe and is located between the steam drum water supply pump and the steam drum, and is used to deoxygenate the water entering the steam drum.

[0009] According to the waste heat recovery system provided in the embodiments of this application, the waste heat recovery system further includes: a first steam pipeline network, a steam drum steam pipe, and a first grid connection valve. The first steam pipeline network is used to connect and utilize the first pressure steam. One end of the steam drum steam pipe is connected to the steam drum, and the other end is connected to the first steam pipeline network. The first grid connection valve is provided on the steam drum steam pipe and is used to control the connection between the steam drum and the first steam pipeline network.

[0010] According to the waste heat recovery system provided in the embodiments of this application, the first steam treatment device further includes: a steam drum pressure gauge, a steam drum temperature gauge, and a steam drum level gauge. The steam drum pressure gauge is installed on the steam drum and is used to monitor the pressure inside the steam drum; the steam drum temperature gauge is installed on the steam drum and is used to monitor the temperature inside the steam drum; the steam drum level gauge is installed on the steam drum and is used to monitor the level inside the steam drum.

[0011] According to the waste heat recovery system provided in the embodiments of this application, the second steam treatment device includes: a buffer package, a second steam pipeline network, a buffer package steam pipe, and a second grid connection valve. The buffer package is connected to the heating device and is used to store the heated first pressure steam and form second pressure steam. The second steam pipeline network is used to connect and utilize the second pressure steam. One end of the buffer package steam pipe is connected to the buffer package, and the other end is connected to the second steam pipeline network. The second grid connection valve is provided on the buffer package steam pipe and is used to control the connection between the buffer package and the second steam pipeline network.

[0012] According to the waste heat recovery system provided in the embodiments of this application, the second steam treatment device further includes: a buffer tank pressure gauge, a buffer tank temperature gauge, and a buffer tank level gauge. The buffer tank pressure gauge is installed on the buffer tank and is used to monitor the pressure inside the buffer tank; the buffer tank temperature gauge is installed on the buffer tank and is used to monitor the temperature inside the buffer tank; the buffer tank level gauge is installed on the buffer tank and is used to monitor the liquid level inside the buffer tank.

[0013] According to the waste heat recovery system provided in the embodiments of this application, the heating device includes: a heating component and a flue gas treatment component. One end of the heating component is connected to a steam drum, and the other end is connected to a buffer tank. The heating component is used to heat the first pressure steam. The flue gas treatment component is connected to the heating component and is used to purify the flue gas inside the heating component.

[0014] According to the waste heat recovery system provided in the embodiments of this application, at least one of the cooling kiln, steam drum, kiln feed water pipe, kiln outlet water pipe, buffer package, and buffer package steam pipe is externally covered with an insulation layer.

[0015] This application also provides a control method for a waste heat recovery system, implemented based on the waste heat recovery system in any of the above embodiments. The control method includes: introducing cooling water into a cooling kiln, where the cooling water is heated by the material in the cooling kiln and vaporized to form initial steam; conveying the initial steam to a first steam treatment device, where a first pressure steam is formed; conveying the first pressure steam to a first steam pipeline network for grid connection or to a heating device for heating and pressurization; when the first pressure steam is conveyed to the heating device, heating the first pressure steam by the heating device and then conveying it to a second steam treatment device, where a second pressure steam is formed inside the second steam treatment device; and conveying the second pressure steam to a power generation device for power generation or to a second steam pipeline network for grid connection.

[0016] This application provides a waste heat recovery system and method. By using a first steam treatment device as a primary buffer container, it can effectively mitigate initial steam pressure changes caused by fluctuations in material temperature or flow rate within the cooling kiln, transforming unstable initial steam into relatively stable first-pressure steam. The first-pressure steam is then forcibly heated by a heating device, increasing its pressure and temperature, and buffered again in a second steam treatment device, resulting in second-pressure steam with even higher pressure and more stable quality. This two-stage storage and intermediate heating combination structure solves the problems of large steam pressure fluctuations with incoming material conditions and difficulty in stable grid connection or power generation in existing technologies. It achieves stable steam production and significantly improves the adaptability and operational reliability of the entire waste heat recovery system to changes in operating conditions. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0018] Figure 1 A schematic diagram of the waste heat recovery system provided in this application;

[0019] Figure 2 A flowchart of the control method for the waste heat recovery system provided in this application.

[0020] Explanation of reference numerals in the attached figures:

[0021] 100: Cooling kiln;

[0022] 200: First steam treatment unit; 210: Steam drum; 220: Kiln feed water pipe; 230: Kiln outlet water pipe; 240: Cooling kiln feed water pump; 250: Steam drum makeup water pipe; 260: Steam drum makeup water pump; 270: Deaerator; 280: First steam pipeline network; 290: Steam drum steam pipe; 291: First grid connection valve; 2010: Rotary valve;

[0023] 211: Steam drum pressure gauge; 212: Steam drum temperature gauge; 213: Steam drum level gauge;

[0024] 300: Heating device; 310: Heating component; 320: Flue gas treatment assembly;

[0025] 311: Afterburner; 312: Gas pipe; 313: Gas valve; 314: Burner nozzle; 315: Steam pipe of the first afterburner; 316: Steam pipe of the second afterburner; 317: Pressure booster valve;

[0026] 321: Flue gas pipe; 322: Desulfurization tower; 323: Fan; 324: Chimney;

[0027] 400: Second steam treatment unit; 410: Buffer pack; 420: Second steam pipeline network; 430: Buffer pack steam pipe; 440: Second grid connection valve;

[0028] 411: Buffer tank pressure gauge; 412: Buffer tank temperature gauge; 413: Buffer tank level gauge;

[0029] 500: Power generation device; 510: Steam valve. Detailed Implementation

[0030] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0031] As described in the background section, in industries such as metallurgy, chemicals, and building materials, high-temperature solid materials (such as steel slag, lithium roasted clinker, and ore pellets) carry a large amount of waste heat after high-temperature reactions or processing. To recover this heat energy, equipment such as cooling kilns is typically used to cool the materials, and the heat is transferred to water through a heat exchange system, converting it into steam for power generation, heating, or industrial production. However, due to the large fluctuations in the incoming temperature and flow rate of high-temperature solid materials, the heat load inside the cooling kiln is unstable, and existing heat exchange systems cannot effectively regulate it. This makes it difficult to stabilize the steam pressure generated inside the cooling kiln, resulting in low efficiency in steam grid connection or power generation.

[0032] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will be described below with reference to the accompanying drawings.

[0033] Reference Figure 1 The waste heat recovery system provided in this application includes: a cooling kiln 100, a first steam treatment device 200, a heating device 300, and a second steam treatment device 400. The cooling kiln 100 is used to vaporize cooling water to form initial steam. The first steam treatment device 200 is connected to the cooling kiln 100 and is used to store the initial steam and form first pressurized steam. The heating device 300 is connected to the first steam treatment device 200 and is used to heat the first pressurized steam. The second steam treatment device 400 is connected to the heating device 300 and is used to store the heated first pressurized steam and form second pressurized steam. The pressure of the second pressurized steam is greater than the pressure of the first pressurized steam.

[0034] Specifically, the cooling kiln 100 is a rotary device used for indirect heat exchange between high-temperature solid materials and cooling water. Its main body is a rotatable cylindrical structure with internal heat exchange tubes to facilitate heat exchange as the material tumbles and moves forward. Initial steam refers to the gaseous water formed when the cooling water absorbs heat from the high-temperature solid material inside the cooling kiln 100 and undergoes a phase change. Its pressure and temperature are directly related to the material's temperature and flow rate. Both the first steam treatment device 200 and the second steam treatment device 400 are pressure vessels with a certain volume, serving to buffer and store steam. For example, they can be vertical cylindrical steel tanks.

[0035] During operation, external cooling water first enters the heat exchange tubes of the cooling kiln 100. The high-temperature solid material continuously tumbles and moves forward within the cooling kiln 100, transferring heat to the cooling water. The cooling water absorbs heat, its temperature rises, and it gradually vaporizes, forming initial steam. This initial steam is then piped to the first steam treatment device 200 for steam-water separation and preliminary storage, forming first-pressure steam with a certain pressure and stability. Next, the first-pressure steam is sent to the heating device 300, where it is reheated by an external heat source, further increasing its temperature and pressure. Finally, the heated high-pressure steam enters the second steam treatment device 400 for storage and buffering, forming second-pressure steam with even higher pressure for subsequent use.

[0036] This embodiment uses the first steam treatment device 200 as a primary buffer container to effectively mitigate initial steam pressure changes caused by fluctuations in material temperature or flow rate within the cooling kiln 100, transforming unstable initial steam into relatively stable first-pressure steam. The first-pressure steam is then forcibly heated by the heating device 300, increasing its pressure and temperature, and buffered again in the second steam treatment device 400, resulting in second-pressure steam with even higher pressure and more stable quality. This two-stage storage and intermediate heating combination solves the problem of large fluctuations in steam pressure with incoming material conditions, making stable grid connection or power generation difficult in existing technologies. It achieves stable steam production and significantly improves the adaptability and operational reliability of the entire waste heat recovery system to changes in operating conditions.

[0037] Reference Figure 1 In some embodiments of this application, the first steam treatment device 200 includes: a steam drum 210, a kiln feed water pipe 220, a kiln outlet water pipe 230, and a cooling kiln feed water pump 240. The steam drum 210 is used to store initial steam and form first pressure steam. One end of the kiln feed water pipe 220 is connected to the inlet of the cooling kiln 100, and the other end is connected to the steam drum 210. One end of the kiln outlet water pipe 230 is connected to the outlet of the cooling kiln 100, and the other end is connected to the steam drum 210. The cooling kiln feed water pump 240 is located in the kiln feed water pipe 220 and is used to pump water from the steam drum 210 to the cooling kiln 100. Both the kiln feed water pipe 220 and the kiln outlet water pipe 230 are connected to the cooling kiln 100 through a rotary valve 2010.

[0038] Specifically, the steam drum 210 in the first steam treatment device 200 is a cylindrical pressure vessel, installed horizontally. Its upper half is a steam space, and its lower half is a water space, used to separate the steam-water mixture and store the steam. The kiln feed pipe 220 is used to transport water from the steam drum 210 to the cooling kiln 100, and the kiln outlet pipe 230 is used to transport the steam-water mixture generated in the cooling kiln 100 back to the steam drum 210. The rotary valve 2010 is a sealing device that enables a sealed connection between a rotating component and a fixed pipe. It has a relatively rotatable sealing surface inside and can withstand certain pressure and temperature.

[0039] Furthermore, the drum 210 is constructed from rolled and welded boiler steel plates, with elliptical end caps at both ends. Multiple pipe seats are provided on the drum for connecting the kiln feed water pipe 220 and the kiln outlet water pipe 230. Both the kiln feed water pipe 220 and the kiln outlet water pipe 230 are made of seamless steel pipe, with their wall thickness calculated based on design pressure and temperature to ensure safe operation under high temperature and high pressure conditions. The fixed end of the rotary valve 2010 is connected to the kiln feed water pipe 220 or the kiln outlet water pipe 230 via a flange, while the rotating end of the rotary valve 2010 is connected to the rotary joint seat at the center of the end of the cooling kiln 100 via a flange. The rotary valve 2010 has a precision-machined spherical sealing pair inside, filled with high-temperature resistant sealing packing. The cooling kiln feed water pump 240 is a multi-stage centrifugal pump, with valves and pressure gauges at both its inlet and outlet for regulating and monitoring its operating status.

[0040] During operation, saturated water in the steam drum 210 is pumped by the cooling kiln feed pump 240 and transported to the inlet of the cooling kiln 100 via the kiln feed pipe 220 and rotary valve 2010. Inside the cooling kiln 100, the water absorbs heat from the materials and partially vaporizes, forming a steam-water mixture. This mixture is then returned to the steam drum 210 via the outlet of the cooling kiln 100, rotary valve 2010, and kiln outlet pipe 230. Upon entering the steam drum 210, due to its large volume, the flow rate decreases, and the steam and water naturally separate under gravity. The steam accumulates at the top of the steam drum 210, while the water settles at the bottom, forming first-pressure steam and circulating water. Through this circulation, the steam drum 210 not only stores steam but also provides a stable cooling water source for the cooling kiln 100.

[0041] This embodiment achieves forced circulation between the cooling kiln 100 and the steam drum 210 by setting up a steam drum 210. The steam drum 210, as the center for steam-water separation and storage, can effectively cope with instantaneous changes in heat load within the cooling kiln 100 and maintain stable water circulation in the system. The application of the rotary valve 2010 solves the connection problem between the rotation of the cooling kiln 100 and the fixed pipeline, ensuring continuous and reliable water flow and sealing during equipment rotation, avoiding pipe twisting or leakage caused by equipment rotation. The cooling kiln feed water pump 240 provides the power required for circulation, ensuring sufficient water flow into the cooling kiln 100 for heat exchange even when there is a certain height difference between the steam drum 210 and the cooling kiln 100.

[0042] Reference Figure 1In some embodiments of this application, the first steam treatment device 200 further includes: a steam drum water supply pipe 250, a steam drum water supply pump 260, and a deaerator 270. The steam drum water supply pipe 250 connects the steam drum 210 to an external water source. The steam drum water supply pump 260 is installed on the steam drum water supply pipe 250 and is used to pump cooling water from the external water source to the steam drum 210. The deaerator 270 is installed on the steam drum water supply pipe 250 and is located between the steam drum water supply pump 260 and the steam drum 210, and is used to deoxygenate the water entering the steam drum 210.

[0043] Specifically, the steam drum makeup water pipe 250 in the first steam treatment unit 200 is a pipeline connecting an external water source to the steam drum 210, used to replenish the water consumed by steam generation in the system. The steam drum makeup water pump 260 is a pressurization device that provides power for makeup water. The deaerator 270 is a water treatment device that works by removing dissolved oxygen from the water through heat, preventing oxygen from causing oxidation and corrosion to the steam drum 210 and the piping system.

[0044] Furthermore, the steam drum water supply pipe 250 is constructed of seamless steel pipe, with its diameter designed according to the system's maximum water supply volume to ensure smooth water flow during replenishment. The steam drum water supply pump 260 is a vertical multi-stage centrifugal pump, whose head needs to overcome the resistance of the deaerator 270 and the pressure inside the steam drum 210. The deaerator 270 is a thermal deaerator, its main body being a pressure vessel with nozzles and a water spray tray inside, and a steam inlet and exhaust port on the outside. Cooling water from the steam drum water supply pump 260 enters the deaerator 270, where it is atomized through the nozzles and comes into full contact with the introduced heating steam. The water temperature rises to the saturation temperature at the corresponding pressure, thereby releasing dissolved oxygen and non-condensable gases from the water. The water is then discharged through the exhaust port, and the deaerated water falls into the water tank at the bottom of the deaerator 270, awaiting replenishment to the steam drum 210.

[0045] During operation, when the liquid level in the steam drum 210 drops to a preset low level due to steam generation, the control system activates the steam drum makeup water pump 260. The steam drum makeup water pump 260 draws water from an external water source, pressurizes it, and sends it to the deaerator 270. Inside the deaerator 270, cooling water and heating steam exchange heat, removing dissolved oxygen and resulting in softened water with extremely low oxygen content. This deoxygenated softened water then flows through the end of the steam drum makeup water pipe 250 and finally enters the steam drum 210. This makeup water process is automatically performed based on the liquid level signal of the steam drum 210 to maintain a dynamic balance of the water level within the steam drum 210.

[0046] This embodiment achieves automatic water replenishment of the system by setting up a steam drum water supply pipe 250 and a steam drum water supply pump 260, ensuring that there is always sufficient water in the steam drum 210 to supply the cooling kiln feed water pump 240, thereby guaranteeing the cooling effect of the cooling kiln 100 and the continuous generation of steam. The setting of the deaerator 270 is also crucial, as it can remove dissolved oxygen from the makeup water, effectively preventing dissolved oxygen from causing pitting and oxidative corrosion on the heat exchange tubes and connecting pipes inside the steam drum 210 and cooling kiln 100 under high temperature conditions, significantly extending the service life and operational safety of the entire waste heat recovery system.

[0047] In other possible embodiments, the deaerator 270 employs a vacuum deaerator, which achieves deoxygenation by creating negative pressure within a sealed container, causing the water to boil at a lower temperature. This method does not require heating steam and is more suitable for scenarios without a stable steam source. Furthermore, a water softener is added to the steam drum makeup water pipe 250 to soften the makeup water, removing calcium and magnesium ions before it is sent to the deaerator 270. This further prevents scaling inside the system and improves heat exchange efficiency.

[0048] Reference Figure 1 In some embodiments of this application, the waste heat recovery system further includes: a first steam pipeline network 280, a steam drum pipe 290, and a first grid connection valve 291. The first steam pipeline network 280 is used to connect and utilize the first pressure steam. One end of the steam drum pipe 290 is connected to the steam drum 210, and the other end is connected to the first steam pipeline network 280. The first grid connection valve 291 is provided on the steam drum pipe 290 and is used to control the connection between the steam drum 210 and the first steam pipeline network 280.

[0049] Specifically, the first steam network 280 refers to the pipeline network within the plant area used for transporting and distributing low-pressure steam, with an inlet steam pressure not exceeding 0.6 MPa, used for heating or industrial heating processes. The steam drum pipe 290 is the channel connecting the steam drum 210 and the first steam network 280. The first connection valve 291 is a control valve installed on the steam drum pipe 290, used to connect or disconnect the steam passage between the steam drum 210 and the first steam network 280.

[0050] Furthermore, the first steam pipeline network 280 is a closed network welded from multiple sections of large-diameter seamless steel pipes, with multiple branch pipe interfaces on its main pipe for supplying steam to various steam-consuming points. The steam drum pipe 290 extends from the steam space at the top of the steam drum 210, and a first grid connection valve 291 is sequentially installed on the steam drum pipe 290. The first grid connection valve 291 is an electrically adjustable valve, capable of adjusting its opening degree according to control system commands. A tee is provided at the branch point of the steam drum pipe 290; one branch connects to the first steam pipeline network 280 via the first grid connection valve 291, and the other branch connects to the heating device 300. The arrangement of the steam drum pipe 290 takes thermal expansion into account, with π-shaped compensators installed at appropriate locations.

[0051] During operation, when the initial steam pressure inside the steam drum 210 reaches a certain value and the first steam pipeline 280 has a demand, the first grid connection valve 291 will open. Steam from the upper part of the steam drum 210, under its own pressure, flows through the steam drum steam pipe 290 and the first grid connection valve 291 into the first steam pipeline 280 for downstream users. When grid connection is not required, the first grid connection valve 291 closes. By controlling the opening degree of the first grid connection valve 291, the steam flow rate entering the first steam pipeline 280 can be adjusted to achieve on-demand steam supply.

[0052] This embodiment provides a direct grid connection for the first-pressure steam generated in the steam drum 210 by setting up a steam pipe 290 and a first grid connection valve 291. When the steam pressure is low or the user has a demand for low-pressure steam, it can be directly connected to the first steam network 280 without subsequent heating and pressurization, simplifying the process and improving the flexibility of energy utilization. This design allows the system to flexibly select the steam utilization method according to actual needs, avoiding excessive processing of steam quality and realizing the cascade utilization of energy.

[0053] In some other possible embodiments, in addition to the first grid connection valve 291, a check valve is also connected in series on the steam pipe 290 of the steam drum to prevent steam in the first steam network 280 from flowing back to the steam drum 210 when the pressure fluctuates, thus ensuring the safe operation of the system. Furthermore, an emergency vent valve is installed at the end of the steam pipe 290 near the steam drum 210. When the pressure inside the steam drum 210 exceeds the safety threshold and other discharge pathways are blocked, the vent valve is opened in an emergency to discharge steam to the atmosphere, serving as overpressure protection.

[0054] Reference Figure 1In some embodiments of this application, the first steam treatment device 200 further includes: a steam drum pressure gauge 211, a steam drum temperature gauge 212, and a steam drum level gauge 213. The steam drum pressure gauge 211 is installed on the steam drum 210 and is used to monitor the pressure inside the steam drum 210; the steam drum temperature gauge 212 is installed on the steam drum 210 and is used to monitor the temperature inside the steam drum 210; the steam drum level gauge 213 is installed on the steam drum 210 and is used to monitor the level inside the steam drum 210.

[0055] Specifically, the steam drum pressure gauge 211 can be a Bourdon tube type pressure gauge, with a range 1.5 times the design pressure of the steam drum 210 and an accuracy class of not less than 1.6. The steam drum pressure gauge 211 is connected to the pressure tapping seat at the top of the steam drum 210 via a bend in the gauge tube. The bend in the gauge tube is filled with condensate water, which isolates the high-temperature steam and protects the internal components of the steam drum pressure gauge 211. The steam drum temperature gauge 212 can be a thermocouple thermometer, with its sensing element inserted into the water space inside the steam drum 210 through a protective sleeve made of heat-resistant stainless steel to prevent high-temperature corrosion. The steam drum level gauge 213 can be a bicolor quartz tube level gauge, directly installed on the side of the steam drum 210, visually displaying the liquid level height through the principle of light refraction.

[0056] During operation, operators read the value of the steam pressure gauge 211 to determine whether the steam pressure inside the steam drum 210 is within the safe operating range, and adjust the operation of the heating device 300 or the first grid-connected valve 291 accordingly. The value of the steam temperature gauge 212 indirectly indicates the steam saturation state, assisting the control system in making adjustments. The reading of the steam drum level gauge 213 is one of the most critical parameters. When the level is lower than the set value, the control system will activate the steam drum water pump 260 to replenish water; when the level is higher than the set value, it will reduce water replenishment to maintain the level within a reasonable range, ensuring the effective steam-water separation of the steam drum 210.

[0057] This embodiment constructs a complete local monitoring system by installing a steam drum pressure gauge 211, a steam drum temperature gauge 212, and a steam drum level gauge 213 on the steam drum 210. These instruments provide real-time and accurate operating parameters for the system's automatic control and stable operation. Relying on these parameters, the control system can precisely adjust the makeup water flow rate and steam output, ensuring that the steam drum 210 always operates in its optimal state. This guarantees the stability of the pressure and output of the first-pressure steam, preventing safety accidents such as dry boiler due to water shortage or steam carryover due to overfilling.

[0058] In other possible embodiments, the steam drum pressure gauge 211 is an electrical contact pressure gauge. When the pressure reaches a preset upper or lower limit, the electrical contact pressure gauge outputs a switching signal to directly control the alarm device, providing faster protection. The steam drum level gauge 213 is a magnetic float level gauge, which is connected to the steam drum 210 through the principle of communicating vessels. The level indication is intuitive and easy to display, and it is easy to install a level alarm switch and a remote transmitter to achieve the dual functions of local indication and remote monitoring.

[0059] Reference Figure 1 In some embodiments of this application, the second steam treatment device 400 includes: a buffer tank 410, a second steam pipeline network 420, a buffer tank steam pipe 430, and a second grid connection valve 440. The buffer tank 410 is connected to the heating device 300 and is used to store heated first-pressure steam and form second-pressure steam. The second steam pipeline network 420 is used to connect and utilize the second-pressure steam. One end of the buffer tank steam pipe 430 is connected to the buffer tank 410, and the other end is connected to the second steam pipeline network 420. The second grid connection valve 440 is disposed on the buffer tank steam pipe 430 and is used to control the connection between the buffer tank 410 and the second steam pipeline network 420. The outlet of the buffer tank 410 is connected to a power generation device 500 through a pipeline, and a steam valve 510 is disposed on the pipeline. The steam valve 510 is used to control the steam from the buffer tank 410 to enter the power generation device 500.

[0060] Specifically, the buffer tank 410 in the second steam processing unit 400 is a pressure vessel with a similar structure to the steam drum 210 but a higher working pressure. It is used to store the heated steam at a higher pressure and serves as a buffer and pressure stabilizer. The second steam pipeline network 420 refers to the pipeline network within the plant area used for transporting and distributing high-pressure steam. Its steam pressure is above 1 MPa and can be used to drive the power generation unit 500 to generate electricity. The buffer tank steam pipe 430 is the pipe connecting the buffer tank 410 and the second steam pipeline network 420. The second grid connection valve 440 is a control valve installed on the buffer tank steam pipe 430.

[0061] Furthermore, the cylinder of the buffer tank 410 is rolled and welded from high-strength low-alloy steel, and its design pressure and temperature are higher than those of the steam drum 210 to meet the storage requirements of high-pressure steam. The buffer tank steam pipe 430 is led out from the steam space at the top of the buffer tank 410 and is made of thick-walled seamless steel pipe. The material and wall thickness of the pipe meet the requirements of high-pressure operation. The second grid-connected valve 440 is a high-pressure shut-off valve. The valve body and valve disc are made of materials with sufficient strength and high-temperature resistance. The sealing surface of the second grid-connected valve 440 is made by overlaying hard alloy to ensure sealing reliability under frequent operation.

[0062] During operation, the high-pressure steam, pressurized by the heating device 300, enters the buffer tank 410. After a brief stay and pressure stabilization within the buffer tank 410, it is then transported to the second steam network 420 via the buffer tank steam pipe 430 and the second grid connection valve 440. When the steam consumption of the second steam network 420 changes, the output of high-pressure steam is controlled by adjusting the opening of the second grid connection valve 440, thereby maintaining the stability of the pressure within the buffer tank 410.

[0063] This embodiment provides a crucial buffer and storage mechanism for the heated high-pressure steam by incorporating a buffer pack 410. Since the heating process of the heating device 300 may experience minor fluctuations, the directly output steam pressure may be unstable. The buffer pack 410, utilizing its volumetric advantage, can effectively smooth these pressure fluctuations, resulting in a more stable output of high-pressure steam. This is essential for turbine power generation, which requires a stable pressure input. Simultaneously, the configuration of the buffer pack steam pipe 430 and the second grid connection valve 440 allows the system to flexibly and stably integrate high-pressure steam into the second steam network 420 according to the needs of the downstream pipeline network, achieving efficient energy transmission and distribution.

[0064] In other possible embodiments, the bottom of the buffer tank 410 is provided with a drain outlet and a condensate draining device to periodically discharge the small amount of condensate that forms during storage due to heat dissipation, preventing moisture from entering downstream equipment with the steam, avoiding water hammer accidents, and protecting equipment safety. Furthermore, a check valve is installed on the steam pipe 430 of the buffer tank before the second grid connection valve 440 to prevent backflow when the steam pressure of the second steam network 420 is higher than the internal pressure of the buffer tank 410, ensuring unidirectional flow and safe operation of the system.

[0065] Reference Figure 1 In some embodiments of this application, the second steam treatment device 400 further includes: a buffer tank pressure gauge 411, a buffer tank temperature gauge 412, and a buffer tank level gauge 413. The buffer tank pressure gauge 411 is disposed on the buffer tank 410 and is used to monitor the pressure inside the buffer tank 410; the buffer tank temperature gauge 412 is disposed on the buffer tank 410 and is used to monitor the temperature inside the buffer tank 410; and the buffer tank level gauge 413 is disposed on the buffer tank 410 and is used to monitor the level inside the buffer tank 410.

[0066] Specifically, the pressure gauge 411 of the buffer tank has a range that matches the design pressure of the buffer tank 410. Its installation method is similar to that of the steam drum pressure gauge 211, connecting to the pressure tap of the buffer tank 410 via a condenser coil. The temperature gauge 412 of the buffer tank is installed in the steam space of the buffer tank 410 to monitor the temperature of the high-pressure steam. The level gauge 413 of the buffer tank is used to monitor the level of condensate that may accumulate at the bottom of the buffer tank 410. It is installed at a low position, has a small range, and is a magnetic level gauge for easy on-site observation.

[0067] During operation, operators observe the readings of the pressure gauge 411 and temperature gauge 412 of the buffer tank to determine whether the steam parameters entering the buffer tank 410 meet the design requirements. Based on pressure changes, they adjust the heat load of the front-end heating device 300 or the opening of the rear-end second grid-connected valve 440. The level gauge 413 of the buffer tank is used to assess the accumulation of condensate within the buffer tank 410. When the level reaches a certain height, the bottom drain valve is opened to discharge the condensate, preventing excessive water level from flooding the steam space and affecting steam quality.

[0068] This embodiment improves the monitoring of the high-pressure steam system by installing a pressure gauge 411, a temperature gauge 412, and a level gauge 413 on the buffer tank 410. The pressure gauge 411 and temperature gauge 412 ensure that the parameters of the high-pressure steam are within a controllable range, providing qualified steam quality for downstream power generation. The level gauge 413 solves the problem of condensate accumulation in the high-pressure vessel. Timely drainage effectively prevents moisture from entering the high-speed rotating power generation equipment with the high-pressure steam, avoiding water hammer and blade damage, and playing a crucial role in ensuring equipment safety.

[0069] In other possible embodiments, these instruments are connected to a control system to achieve automatic control. When the buffer tank pressure gauge 411 detects that the pressure exceeds the set value, the control system automatically closes the fuel valve of the heating device 300; when the buffer tank level gauge 413 detects a high level, the control system automatically opens the drain valve to drain the water, without the need for manual intervention, thus improving the automation level and safety of the system.

[0070] Reference Figure 1 In some embodiments of this application, the heating component 310 and the flue gas treatment component 320 are connected. One end of the heating component 310 is connected to the steam drum 210 and the other end is connected to the buffer package 410. The heating component 310 is used to heat the first pressure steam. The flue gas treatment component 320 is connected to the heating component 310 and is used to purify the flue gas inside the heating component 310.

[0071] Specifically, the heating element 310 in the heating device 300 is the core equipment for heating and pressurizing the first-pressure steam, and it has an internal passage for steam to pass through and a combustion chamber to provide a heat source. The flue gas treatment assembly 320 is a combination of equipment used to purify the exhaust gas generated after the combustion of the heating element 310 to meet environmental emission requirements.

[0072] Furthermore, the heating component 310 is a combustion engine 311, whose main structure includes a combustion chamber and a serpentine coil arranged within the combustion chamber. The coil inlet of the combustion engine 311 is connected to the steam outlet of the steam drum 210 via a first combustion engine steam pipe 315, and the coil outlet of the combustion engine 311 is connected to the buffer tank 410 via a second combustion engine steam pipe 316. A burner nozzle 314 is installed at the bottom of the combustion engine 311, and the burner nozzle 314 is connected to an external gas source via a gas pipe 312. A gas valve 313 is provided on the gas pipe 312 for regulating the gas flow rate. The flue gas treatment assembly 320 includes a desulfurization tower 322, the inlet of which is connected to the exhaust outlet of the combustion engine 311 via a flue gas pipe 321. The desulfurization tower 322 is equipped with a spray layer for spraying an alkaline solution to absorb sulfur oxides in the flue gas. The outlet of desulfurization tower 322 is connected to fan 323 via a pipeline, and the outlet of fan 323 is connected to chimney 324.

[0073] During operation, the first pressurized steam from the steam drum 210 enters the coil of the afterburner 311. Simultaneously, the gas valve 313 opens, and gas flows through the gas pipe 312 and burner nozzle 314 into the combustion chamber of the afterburner 311 and ignites. The resulting high-temperature flame and flue gas wash over the outer wall of the coil, heating the steam inside. The heated steam, with its increased pressure and temperature, flows out from the coil outlet and into the buffer tank 410. The flue gas produced by combustion enters the desulfurization tower 322 through the flue gas pipe 321, where it comes into full contact with the alkaline scrubbing liquid, absorbing and removing sulfur oxides. The purified flue gas is then drawn by the fan 323 and finally discharged into the atmosphere through the chimney 324.

[0074] This embodiment, by setting up a heating component 310 and using a secondary burner 311 as the heat source, can actively reheat the first-pressure steam output from the steam drum 210, significantly increasing its temperature and pressure to meet the quality requirements of high-pressure steam. This solves the problem that previous systems could only produce low-pressure steam, limiting their utilization. Simultaneously, by setting up a flue gas treatment component 320, the flue gas generated by the secondary burner 311 is desulfurized, effectively reducing the emission of pollutants such as sulfur dioxide. This ensures that the entire waste heat recovery system meets environmental protection requirements, achieving the dual goals of energy recovery and environmental protection.

[0075] In some other possible embodiments, the heating component 310 uses a thermal oil furnace as the heating source, first heating the thermal oil, and then using the thermal oil to heat the steam through a heat exchanger. This method can achieve more precise temperature control, and the system operates at a lower pressure, resulting in higher safety. Furthermore, the flue gas treatment component 320 adds a bag filter before the desulfurization tower 322 to remove particulate matter from the flue gas, further reducing emissions.

[0076] In some embodiments of this application, at least one of the cooling kiln 100, steam drum 210, kiln water supply pipe 220, kiln water outlet pipe 230, buffer package 410 and buffer package steam pipe 430 is externally covered with an insulation layer.

[0077] Specifically, thermal insulation refers to a layer of heat-insulating material applied to the outer surface of equipment and pipelines to reduce heat loss to the external environment and improve energy efficiency. The materials used in thermal insulation have good thermal insulation properties and a certain degree of mechanical strength.

[0078] Furthermore, the outer wall of the cooling kiln 100 is covered with multiple layers of insulation material, using aluminum silicate fiber blankets, and then wrapped with a layer of galvanized iron sheet as a protective layer, which not only prevents the insulation material from being damaged by moisture but also provides protection. The steam drum 210, buffer drum 410, and their connected kiln feed water pipe 220, kiln outlet water pipe 230, and buffer drum steam pipe 430 also use a similar insulation structure. For the insulation of the kiln feed water pipe 220, kiln outlet water pipe 230, and buffer drum steam pipe 430, a layer of high-temperature resistant aluminum silicate fiber shell is first wrapped, then galvanized iron sheet is used as the outer protective shell, and it is secured with steel straps. The thickness of the insulation material is calculated based on the pipe diameter and the internal medium temperature.

[0079] During operation, the insulation layer continuously functions to isolate the high-temperature surfaces of the cooling kiln 100, steam drum 210, buffer tank 410, and their connecting pipes from the surrounding environment. Because the insulation layer has extremely low thermal conductivity, it significantly slows down the rate of heat transfer from the high-temperature equipment surface to the ambient air, thus ensuring that the vast majority of the heat is retained within the working medium inside the system.

[0080] This embodiment significantly reduces heat loss in the entire waste heat recovery system by covering these key equipment and pipelines with insulation layers. Insulation of the cooling kiln 100 prevents heat loss and improves the efficiency of heat transfer from materials to water. Insulation of the steam drum 210 and buffer tank 410 reduces temperature drop and condensation of steam during storage, ensuring steam quality. Insulation of the kiln feed pipe 220, kiln outlet pipe 230, and buffer tank steam pipe 430 ensures stable steam parameters during transport, preventing partial steam condensation due to heat dissipation along the route, thus improving overall heat recovery efficiency and system operational economy.

[0081] In other possible embodiments, the insulation material is optimized according to the temperature range. In the high-temperature cooling kiln shell area 100, a nanoporous insulation material with higher temperature resistance and lower thermal conductivity is used to achieve better insulation effect with a thinner thickness, reducing the load on the equipment. For valves, flanges, and other parts requiring frequent maintenance, removable insulation sleeves are installed for easy maintenance while ensuring the continuity of insulation.

[0082] In any of the above embodiments, the design pressure of the cooling kiln 100, the steam drum 210 kiln feed water pipe 220, the kiln outlet water pipe 230, the cooling kiln feed water pump 240, the steam drum makeup water pipe 250, the steam drum makeup water pump 260, the steam drum steam pipe 290, the first grid connection valve 291, and the booster valve 317 are all greater than 1 MPa. The design pressure of the second auxiliary combustion engine steam pipe 316, the steam valve 510, the buffer package 410, the buffer package steam pipe 430, and the second grid connection valve 440 are all greater than 1.6 MPa.

[0083] Reference Figure 2 This application also provides a control method for a waste heat recovery system, which is implemented based on the waste heat recovery system in any of the above embodiments. Specifically, the control method includes the following steps: S1, cooling water is introduced into the cooling kiln 100, and the cooling water is heated by the material in the cooling kiln 100 and vaporized to form initial steam; S2, the initial steam is transported to the first steam treatment device 200, and a first pressure steam is formed in the first steam treatment device 200; S3, the first pressure steam is transported to the first steam pipeline network 280 for grid connection or to the heating device 300 for heating and pressurization; S4, when the first pressure steam is transported to the heating device 300, the first pressure steam is heated by the heating device 300 and then transported to the second steam treatment device 400, and a second pressure steam is formed inside the second steam treatment device 400; S5, the second pressure steam is transported to the power generation device 500 for power generation or to the second steam pipeline network 420 for grid connection.

[0084] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the claims.

[0085] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A waste heat recovery system, characterized in that, include: Cooling kiln (100) is used to vaporize cooling water to form initial steam; A first steam treatment device (200) is connected to the cooling kiln (100), and the first steam treatment device (200) is used to store the initial steam and form first pressure steam; A heating device (300) is connected to the first steam treatment device (200), and the heating device (300) is used to heat the first pressurized steam; The second steam treatment device (400) is connected to the heating device (300) and is used to store the heated first pressure steam and form second pressure steam. The pressure of the second pressurized vapor is greater than the pressure of the first pressurized vapor.

2. The waste heat recovery system according to claim 1, characterized in that, The first steam treatment device (200) includes: Steam drum (210) is used to store the initial steam and form the first pressurized steam; The kiln water supply pipe (220) is connected at one end to the water inlet of the cooling kiln (100) and at the other end to the steam drum (210); The kiln outlet pipe (230) is connected at one end to the outlet of the cooling kiln (100) and at the other end to the steam drum (210); A cooling kiln feed water pump (240) is installed in the kiln feed water pipe (220) and is used to pump water from the steam drum (210) to the cooling kiln (100).

3. The waste heat recovery system according to claim 2, characterized in that, The first steam treatment device (200) further includes: A steam drum water supply pipe (250) connects the steam drum (210) to an external water source; A steam drum water supply pump (260) is installed on the steam drum water supply pipe (250) and is used to pump cooling water from the external water source to the steam drum (210). A deaerator (270) is installed on the steam drum water supply pipe (250) and located between the steam drum water supply pump (260) and the steam drum (210), and is used to deoxygenate the water entering the steam drum (210).

4. The waste heat recovery system according to claim 3, characterized in that, The waste heat recovery system also includes: The first steam pipeline network (280) is used to connect the first pressurized steam to the grid for utilization; The steam pipe (290) of the steam drum is connected at one end to the steam drum (210) and at the other end to the first steam pipe network (280); The first connection valve (291) is located on the steam pipe (290) of the steam drum and is used to control the connection between the steam drum (210) and the first steam network (280).

5. The waste heat recovery system according to any one of claims 2-4, characterized in that, The first steam treatment device (200) further includes: A pressure gauge (211) is installed on the steam drum (210) to monitor the pressure inside the steam drum (210); A steam drum temperature gauge (212) is installed on the steam drum (210) to monitor the temperature inside the steam drum (210); A steam drum level gauge (213) is installed on the steam drum (210) to monitor the liquid level inside the steam drum (210).

6. The waste heat recovery system according to claim 2, characterized in that, The second steam treatment device (400) includes: A buffer pack (410), connected to the heating device (300), is used to store the heated first pressure steam and form a second pressure steam; The second steam pipeline (420) is used to connect the second pressure steam to the grid for utilization; The buffer pack steam pipe (430) is connected at one end to the buffer pack (410) and at the other end to the second steam pipe network (420); The second connection valve (440) is located on the steam pipe (430) of the buffer package and is used to control the connection between the buffer package (410) and the second steam network (420).

7. The waste heat recovery system according to claim 6, characterized in that, The second steam treatment device (400) further includes: A pressure gauge (411) is installed on the buffer (410) to monitor the pressure inside the buffer (410); A temperature gauge (412) is installed on the buffer pack (410) to monitor the temperature inside the buffer pack (410); A buffer level gauge (413) is installed on the buffer (410) to monitor the liquid level inside the buffer (410).

8. The waste heat recovery system according to claim 6, characterized in that, The heating device (300) includes: The heating element (310) is connected at one end to the steam drum (210) and at the other end to the buffer pack (410). The heating element (310) is used to heat the first pressure steam. A flue gas treatment assembly (320) is connected to the heating component (310) and is used to purify the flue gas inside the heating component (310).

9. The waste heat recovery system according to claim 6, characterized in that, At least one of the cooling kiln (100), the steam drum (210), the kiln water supply pipe (220), the kiln water outlet pipe (230), the buffer package (410), and the buffer package steam pipe (430) is externally covered with an insulation layer.

10. A control method for a waste heat recovery system, characterized in that, Based on the waste heat recovery system according to any one of claims 1-9, the control method includes: Cooling water is introduced into the cooling kiln (100), and the cooling water is heated by the material in the cooling kiln (100) and then vaporized to form the initial steam; The initial steam is delivered to a first steam processing device (200), and the first pressurized steam is formed within the first steam processing device (200); The first pressurized steam is transported to the first steam network (280) for grid connection or to the heating device (300) for heating and pressurization; When the first pressurized steam is delivered to the heating device (300), the first pressurized steam is heated by the heating device (300) and then delivered to the second steam processing device (400), where the second pressurized steam is formed inside the second steam processing device (400); The second pressurized steam is delivered to the power generation unit (500) for power generation, or delivered to the second steam network (420) for grid connection.

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