Double-channel inner-regulating tunnel kiln waste heat power generation boiler

Abstract

The present application relates to a kind of double-channel inner adjustment type tunnel kiln waste heat power generation boiler, including tunnel kiln;And, across the boiler arranged on tunnel kiln;Boiler includes two parallel distribution flues and air ducts, and the flue and air duct shared boiler drum and steam collector;Flue and the air duct are communicated with tunnel kiln by pipeline respectively;Flue and the air duct in the heat medium flow from in to out are sequentially provided with ash bucket, multiple superheaters, multiple evaporators and multiple energy savers.The present application not only has compact boiler structure, simplifies the construction mode of existing boiler, reduces investment and operating cost, but also realizes the mutual complementation of two kinds of heat medium in the process of heat conversion in furnace under the condition of independent each other, maximumly guarantees the stability of boiler operating parameter in the process of temperature control and adjustment of tunnel kiln, improves the safety, high efficiency of power generation system, also realizes the fine temperature control of tunnel kiln, and has important significance to improve brick quality.

Description

Technical Field

[0001] This invention relates to the field of waste heat boiler technology for tunnel kilns, and in particular to a dual-channel internally adjustable waste heat power generation boiler for tunnel kilns. Background Technology

[0002] Coal gangue is a solid waste generated during coal mining and washing. Due to its low economic value, it has been difficult to achieve widespread industrial application. In recent years, with the support of relevant national policies, using coal gangue to make bricks has become an important way to control the increase and decrease the stock of coal gangue. Because coal gangue contains coal-like components, has a high calorific value, and its distribution is extremely uneven, using coal gangue to make bricks releases more heat, at a higher temperature, and is unstable during the firing process compared to traditional clay brick making, which adversely affects the control of brick quality. Therefore, using waste heat boilers to recover the residual heat of the heat transfer medium (flue gas and air) in the kiln to control the kiln temperature has become a common choice in tunnel kiln brick making technology.

[0003] Due to its continuous production, large scale, controllable quality, and energy efficiency, the tunnel kiln has become the main thermal equipment in modern coal gangue brick-making technology. In the tunnel kiln, dried brick blanks are loaded onto trucks and enter from the front end. After passing through the preheating zone, firing zone, and cooling zone, the finished bricks are discharged from the kiln tail. Cold air (wind) is introduced into the kiln from the tail, heated in the cooling zone, and then participates in combustion in the firing zone. The resulting flue gas flows counter-currently to the preheating zone at the kiln head to preheat the incoming brick blanks. The cooled flue gas is then directed to the drying kiln, and the flue gas discharged from the drying kiln is purified before being discharged in compliance with standards.

[0004] To achieve precise temperature control along the tunnel kiln, multiple interfaces for extracting high-temperature heat transfer media (flue gas and air) and for returning cold air are installed in both the firing and cooling zones. The properties of the heat transfer media extracted from different sections of the tunnel kiln vary significantly. For example, the firing zone extracts flue gas, which has a higher temperature, higher dust content, and contains SO2, exhibiting low-temperature corrosiveness; the cooling zone extracts air, which has a slightly lower temperature, lower dust content, and is essentially non-corrosive. If a single-channel waste heat boiler is used to mix the extracted heat transfer media before entering the boiler, only one induced draft fan can extract the flue gas (air). Due to the numerous extraction points and significant pressure differences throughout the tunnel kiln, precise temperature control is difficult, affecting brick quality. Furthermore, the mixed flue gas cannot be returned to the kiln as hot air, increasing exhaust heat loss and flue gas purification costs. Using two independent waste heat boilers, one to recover heat from the flue gas extracted from the firing zone and the other from the air extracted from the cooling zone, would complicate the waste heat recovery system and significantly increase investment costs.

[0005] To address this, we propose a dual-channel internally adjustable tunnel kiln waste heat power generation boiler. Summary of the Invention

[0006] To address the shortcomings of the existing production technologies, the applicant provides a dual-channel internally adjustable tunnel kiln waste heat power generation boiler, which enables two heat transfer media to complement each other during the heat conversion process in the furnace while operating independently, thereby maximizing the stability of boiler operating parameters during the temperature control and regulation process in the tunnel kiln.

[0007] The technical solution adopted in this invention is as follows:

[0008] A dual-channel internally controlled tunnel kiln waste heat power generation boiler includes a tunnel kiln; and a boiler arranged across the tunnel kiln.

[0009] The boiler includes two parallel flue and air duct, as well as a boiler drum and steam collector shared by the flue and air duct.

[0010] The flue and the air duct are respectively connected to different areas of the tunnel kiln through pipes and extract the heat transfer medium in the corresponding areas.

[0011] The flue and the air duct are equipped with ash hoppers, multiple superheaters, multiple evaporators and multiple energy savers in sequence from the inflow to the outflow of the heat transfer medium;

[0012] The multiple energy-saving devices in the flue and air duct are connected in series on the boiler drum to form an energy-saving device regulation system;

[0013] The multiple evaporators in the flue and air duct are connected in parallel to the boiler drum through their respective pipes to form an evaporator regulation system;

[0014] The multiple superheaters in the flue and air duct are connected in series between the boiler drum and the steam collector to form a superheater regulation system.

[0015] Its further features are:

[0016] The tunnel kiln includes a preheating zone, a firing zone, and a cooling zone that are continuously arranged. The flue is connected to the firing zone of the tunnel kiln through a pipe and extracts high-temperature flue gas from the firing zone. The air duct is connected to the cooling zone of the tunnel kiln through a pipe and extracts high-temperature air from the cooling zone.

[0017] The boiler adopts an inverted "U" shape structure and is arranged above the tunnel kiln. The flue and air duct also adopt an inverted "U" shape structure and are connected in the same boiler through a steel structure. The inlet and outlet of the flue and air duct are located at the bottom.

[0018] The ash hoppers in the flue and the air duct include an inlet ash hopper and an outlet ash hopper. The inlet ash hopper is internally insulated and has an inlet ash discharge valve below it. The deposited particles are discharged periodically. The outlet ash hopper is externally insulated and has an outlet ash discharge valve below it. The inlet and outlet ash hoppers are equipped with heat transfer medium inlets and outlets respectively. Both heat transfer medium outlets are connected to induced draft fans to transport the heat transfer medium to the drying kiln for deep utilization of waste heat. The heat transfer medium located in the air duct can also be transported to the tunnel kiln for recycling.

[0019] The various types of heated equipment in the flue and air duct are arranged side by side, and each level of heated equipment is equipped with a shock wave soot blower. The heated equipment includes superheaters, evaporators and energy savers.

[0020] The energy-saving device is equipped with an energy-saving device inlet header and an energy-saving device outlet header according to the water flow direction. At the same time, an energy-saving device outlet header thermocouple is installed on the energy-saving device outlet header, and an energy-saving device inlet electric regulating valve is installed on the water supply pipe of the energy-saving device inlet header.

[0021] The number of evaporators in the flue is greater than the number of evaporators in the air duct. That is, an evaporator is placed in front of the flue, and an evaporator inlet header and an evaporator outlet header are set on the evaporator according to the water flow direction.

[0022] The pipes leading from the boiler drum to the inlet headers of the two superheaters are equipped with electric regulating valves for superheater steam inlet.

[0023] The superheater inlet header is arranged on one side of the heat transfer medium inlet, and the superheater outlet header is arranged on the low-temperature side of the heat transfer medium. A superheater spray desuperheater is installed between the low-temperature section and the high-temperature section of the superheater, and desuperheater thermocouples are respectively installed at the steam inlet and steam outlet ends of the superheater spray desuperheater. Superheater outlet header thermocouples are also respectively installed on the superheater outlet header, and steam header thermocouples are installed on the steam collecting header.

[0024] The evaporators are located at the rear end of the superheater, and each evaporator is connected to the boiler drum through a separate evaporator outlet pipe, forming an independent natural circulation system.

[0025] The beneficial effects of this invention are as follows:

[0026] This invention not only features a compact boiler structure, simplifying existing boiler construction methods and reducing investment and operating costs, but also enables two heat transfer media to complement each other during the heat conversion process in the furnace while operating independently. This maximizes the stability of boiler operating parameters during temperature control in the tunnel kiln, improving the safety and efficiency of the power generation system and achieving precise temperature control of the tunnel kiln, which is of great significance for improving the quality of brick products.

[0027] In addition, the present invention also has the following advantages:

[0028] 1. This application achieves the work that originally required two boilers (a waste heat boiler for extracting flue gas in the firing zone and a waste heat boiler for extracting air in the cooling zone) with only one boiler, greatly simplifying the temperature control and waste heat utilization system of the tunnel kiln and reducing project investment and operating costs.

[0029] 2. This application not only solves the problem that the premixing of flue gas extracted from the firing zone and air extracted from the cooling zone before entering the waste heat boiler caused by the difficulty in accurately controlling the temperature regulation of the tunnel kiln and affecting the quality of bricks, but also solves the problem that the mixed flue gas cannot be sent back to the tunnel kiln for temperature regulation.

[0030] 3. The low-temperature hot air discharged from the waste heat boiler is returned to the tunnel kiln, which can reduce the amount of cold air supplied to the tunnel kiln, thereby reducing the amount of flue gas discharged from the system, reducing the construction investment and operating costs of the flue gas purification system, and also reducing the heat loss of flue gas and the amount of waste gas emissions, which is conducive to energy conservation and environmental protection.

[0031] 4. The heating equipment at each level in the two channels of the waste heat boiler is independent of each other but interconnected through system pipelines. By adjusting the flow rate of the working medium, the heat release of the two heat transfer media (flue gas and air) is mutually supplemented and coordinated, which increases the means of boiler exhaust temperature regulation. It can achieve precise control of exhaust temperature without changing the air extraction volume, thereby ensuring the working temperature of the drying kiln and the air return temperature of the tunnel kiln, and improving the stability of brick quality.

[0032] 5. The heating equipment at each stage within the two channels of the waste heat boiler can be designed specifically for the different properties of the heat transfer media (flue gas and air). For example, the flue gas channel contains a lot of dust and is corrosive; therefore, a lower design flue gas velocity for its heating equipment can prevent wear, while a higher exhaust temperature is beneficial for corrosion prevention and further utilization in the drying kiln. The air channel contains less dust and is non-corrosive; therefore, a slightly higher design flue gas velocity for its heating equipment can enhance heat exchange, while a lower exhaust temperature can not only improve the thermal efficiency of the waste heat boiler but also facilitate temperature control in the return tunnel kiln.

[0033] 6. Because the flue gas contains a high concentration of SO2, if the exhaust gas temperature of the waste heat boiler is too low, the temperature of the tube wall of its flue gas economizer will drop to the sulfuric acid dew point, causing low-temperature corrosion. For single-channel waste heat boilers, the exhaust gas temperature cannot be adjusted. However, for this application, the heat release of the flue gas can be reduced by decreasing the working fluid flow rate of its flue gas economizer and flue gas superheater, thereby increasing the exhaust gas temperature and preventing low-temperature corrosion. The service life and safety of the equipment can be reliably guaranteed.

[0034] 7. When the heat transfer medium extraction rate and extraction temperature change, the relative stability of boiler steam parameters can be maintained through coordinated control of internal heat exchange between the two channels, thereby ensuring the stability and reliability of the steam turbine generator set.

[0035] 8. The waste heat boiler adopts a dual-channel design, and the heating equipment is designed specifically according to the properties of the heat transfer medium. This not only improves the reliability and thermal characteristics of the boiler, but also makes the boiler structure more compact, improves the utilization rate of steel, and saves construction costs.

[0036] 9. All heating equipment in both channels of the waste heat boiler adopts a modular tube box design, is assembled in the factory, and can be quickly installed on site, shortening the construction period. While ensuring project quality, it can also reduce installation and construction costs.

[0037] 10. The waste heat boiler adopts a dual-channel design. The heated equipment in the two channels can select different shock wave blowing frequencies for ash removal according to the difference in ash accumulation speed and degree, which helps to save energy and reduce operating costs.

[0038] 11. The flue evaporator and the air duct evaporator in the two channels of the waste heat boiler adopt independent natural circulation loops, which can avoid mutual influence between different loops and ensure the reliability of boiler hydrodynamics. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of the present invention.

[0040] Figure 2 This is an enlarged schematic diagram of the boiler structure in this invention.

[0041] Figure 3 for Figure 1 A sectional view of section AA in the middle.

[0042] Figure 4 for Figure 1 A sectional view of section BB in the middle.

[0043] Figure 5 This is a schematic diagram of the energy-saving regulator system of the present invention.

[0044] Figure 6 This is a schematic diagram of the evaporator regulation system of the present invention.

[0045] Figure 7 This is a schematic diagram of the superheater regulation system of the present invention.

[0046] in:

[0047] 10. Flue; 11. Flue superheater; 12. Flue evaporator; 13. Flue energy saver;

[0048] 20. Air duct; 21. Air duct superheater; 22. Air duct evaporator; 23. Air duct energy saver;

[0049] 31. Boiler drum; 32. Steam header;

[0050] 41. Inlet header of flue gas energy saver; 42. Outlet header of flue gas energy saver; 43. Inlet header of flue gas evaporator; 44. Outlet header of flue gas evaporator; 45. Inlet header of flue gas superheater; 46. Flue gas superheater spray desuperheater; 47. Outlet header of flue gas superheater; 48. Downcomer of flue gas evaporator; 49. Outlet pipe of flue gas evaporator;

[0051] 51. Inlet header of duct energy-saving device; 52. Outlet header of duct energy-saving device; 53. Inlet header of duct evaporator; 54. Outlet header of duct evaporator; 55. Inlet header of duct superheater; 56. Water spray desuperheater of duct superheater; 57. Outlet header of duct superheater; 58. Downcomer of duct evaporator; 59. Outlet pipe of duct evaporator;

[0052] 60. Shockwave soot blower;

[0053] 70. Steel structure;

[0054] 80. Flue ash hopper; 81. Flue inlet; 82. Flue inlet ash hopper; 83. Flue inlet ash discharge valve; 84. Flue outlet; 85. Flue outlet ash hopper; 86. Flue outlet ash discharge valve;

[0055] 90. Duct ash hopper; 91. Duct air inlet; 92. Duct inlet ash hopper; 93. Duct inlet ash discharge valve; 94. Duct air outlet; 95. Duct outlet ash hopper; 96. Duct outlet ash discharge valve;

[0056] 100. Tunnel kiln; 101. Preheating zone; 102. Firing zone; 103. Cooling zone;

[0057] 01. Electric regulating valve for energy-saving device inlet water; 02. Electric regulating valve for superheater inlet steam; 03. Thermocouple for energy-saving device outlet header; 04. Thermocouple for desuperheater; 05. Thermocouple for superheater outlet header; 06. Thermocouple for steam collector header.

[0058] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0059] like Figures 1-7 As shown, this embodiment of a dual-channel internally adjustable tunnel kiln waste heat power generation boiler includes a tunnel kiln 100, which includes a preheating zone 101, a firing zone 102, and a cooling zone 103 that are continuously arranged.

[0060] The boiler connected between the firing zone 102 and the cooling zone 103 in the tunnel kiln 100 is designed with an inverted "U" shape to facilitate the connection between the flue 10 and the air duct 20 and the tunnel kiln 100. The boiler is arranged above the tunnel kiln 100, and the inlet and outlet of the flue 10 and the air duct 20 are located below.

[0061] The boiler is equipped with parallel flue 10 and air duct 20, which are fixed by steel structure 70. Flue 10 is connected to the firing zone 102 of the tunnel kiln 100 through a pipe and extracts high-temperature flue gas from the firing zone 102. Air duct 20 is connected to the cooling zone 103 of the tunnel kiln 100 through a pipe and extracts high-temperature air from the cooling zone 103.

[0062] Both flue 10 and air duct 20 adopt an inverted "U" shaped structure;

[0063] The flue 10 is provided with a flue ash hopper 80, multiple flue superheaters 11, multiple flue evaporators 12 and multiple flue energy savers 13 in sequence from the flue gas inflow to the flue gas outflow. The flue ash hopper 80 includes a flue inlet ash hopper 82 and a flue outlet ash hopper 85. The flue inlet ash hopper 82 and the flue outlet ash hopper 85 are respectively provided with a flue inlet 81 and a flue outlet 84.

[0064] The air duct 20 is provided with an air duct ash hopper 90, multiple air duct superheaters 21, multiple air duct evaporators 22 and multiple air duct energy savers 23 in sequence from air inflow to air outflow. The air duct ash hopper 90 includes an air duct inlet ash hopper 92 and an air duct outlet ash hopper 95, and an air duct inlet 91 and an air duct outlet 94 are correspondingly provided on the air duct inlet ash hopper 92 and the air duct outlet ash hopper 95.

[0065] Both the air outlet 94 of the air duct and the flue outlet 84 of the flue are connected to induced draft fans to transport the heat transfer medium to the drying kiln for deep utilization of waste heat. At the same time, since there are fewer air impurities in the air duct 20, it can also be transported to the tunnel kiln 100 for temperature regulation of the firing zone 102 and the cooling zone 103.

[0066] like Figure 5 As shown, in this embodiment, multiple series-connected flue gas energy savers 13 in flue 10 and multiple series-connected air duct energy savers 23 in air duct 20 are connected to the same boiler drum 31 through pipes to form an energy saver regulation system. The energy savers are equipped with an energy saver inlet header and an energy saver outlet header according to the water flow direction. At the same time, an energy saver outlet header thermocouple 03 is provided on the energy saver outlet header.

[0067] like Figure 6 As shown, in this embodiment, multiple flue evaporators 12 in flue 10 and multiple air evaporators 22 in air duct 20 are connected to the same boiler drum 31 through their respective pipes to form an evaporator regulation system. Since the temperature of the flue gas is high, the number of flue evaporators 12 in flue 10 is greater than the number of air evaporators 22 in air duct 20. That is, a pre-evaporator is added to flue 10. At the same time, flue evaporator inlet header 43 and flue evaporator outlet header 44 are set on flue evaporator 12 according to the water flow direction, and air evaporator inlet header 53 and air evaporator outlet header 54 are set on air evaporator 22 according to the water flow direction.

[0068] like Figure 7 As shown, in this embodiment, multiple superheaters 11 connected in series in the flue 10 and multiple superheaters 21 connected in series in the air duct 20 are connected between the boiler drum 31 and the steam collector 32 through a saturated steam pipe to form a superheater regulation system, which is used to reheat the steam in the boiler drum 31 and deliver it to the steam collector 32. The steam collector 32 then delivers the superheated steam for power generation.

[0069] Furthermore, all similar heating devices (i.e., energy savers, superheaters, and evaporators) are arranged side by side;

[0070] Common components include boiler drum 31, steam collector 32, shock wave soot blower 60, and steel structure 70.

[0071] The flue inlet ash hopper 82 and the air duct inlet ash hopper 92 are internally insulated. Corresponding flue inlet ash discharge valves 83 and 93 are installed below the flue inlet ash hopper 82 and the air duct inlet ash hopper 92, and the deposited particulate matter is discharged periodically.

[0072] The pre-flue evaporator 12 inside the flue 10 allows for natural circulation of the working fluid, which can quickly reduce the inlet flue temperature and protect the flue superheater 11 from coking and blockage. Because the pre-flue evaporator 12 is relatively small, it forms a single module together with the low-temperature section of the flue superheater 11.

[0073] The boiler drum 31 is located at the top, which can provide the maximum power for the circulation of the working fluid in the evaporator and ensure the reliability of natural circulation. The saturated steam pipes leading from the boiler drum 31 to the flue gas superheater inlet header 45 and the air duct superheater inlet header 55 are respectively equipped with superheater inlet electric regulating valves 02, which can perform secondary distribution of steam flow of flue gas superheater 11 and air duct superheater 21 according to the production needs of brick kiln and the superheated steam temperature of boiler.

[0074] like Figure 7 As shown, the low-temperature sections of the flue gas superheater 11 and the air duct superheater 21 are arranged on the high-temperature side of the heat transfer medium (flue gas and air), and the high-temperature sections are arranged on the low-temperature side. This can prevent the wall temperature of the high-temperature sections of the flue gas superheater 11 and the air duct superheater 21 from becoming too high, thereby improving the safety of equipment operation. That is, the flue gas superheater inlet header 45 is arranged on one side of the flue gas inlet. The saturated steam in the flue gas superheater inlet header 45 has a lower temperature and comes into contact with the high-temperature flue gas to achieve a heat exchange effect. The flue gas superheater outlet header 47 is arranged on the low-temperature side of the high-temperature flue gas, which improves safety. The air duct superheater inlet header 55 and air duct superheater outlet header 57 in the air duct 20 are arranged in the same way.

[0075] A flue gas superheater spray desuperheater 46 and a duct superheater spray desuperheater 56 are installed between the low-temperature section and the high-temperature section of the flue gas superheater 11 and the duct superheater 21, respectively. A desuperheater thermocouple 04 is installed at the steam inlet end and the steam outlet end of the flue gas superheater spray desuperheater 46 and the duct superheater spray desuperheater 56, respectively. A superheater outlet header thermocouple 05 is also installed on the flue gas superheater outlet header 47 and the duct superheater outlet header 57, respectively. By adjusting the spray volume of the flue gas superheater spray desuperheater 46 and the duct superheater spray desuperheater 56, the temperature of the superheated steam can be controlled, protecting the flue gas superheater 11 and the duct superheater 21 and preventing overheating.

[0076] Both the flue superheater 11 and the air duct superheater 21 are designed for working fluid temperatures exceeding the rated value by 50°C. This design can improve the adjustment range of heat transfer medium flow and temperature, as well as the boiler's adaptability, while ensuring safety.

[0077] The flue gas superheater outlet header 47 and the duct superheater outlet header 57 are connected to the steam collecting header 32 via steam pipes. Superheated steam is led to the turbine generator unit through the steam collecting header 32. The steam collecting header 32 is equipped with a steam collecting header thermocouple 06 to measure the steam temperature after the superheated steam in the two channels is mixed, providing a basis for steam flow and temperature regulation.

[0078] After the flue superheater 11 and the air duct superheater 21, multi-stage flue evaporators 12 and air duct evaporators 22 are installed. Depending on the temperature range of the heat transfer medium (flue gas and air), the structure of each stage is different. Through independent flue evaporator downcomer 48, air evaporator downcomer 58, flue evaporator outlet pipe 49 and air evaporator outlet pipe 59, each forms an independent natural circulation system, which does not affect each other and ensures the safety of hydrodynamics.

[0079] The final stage heating equipment consists of a two-stage flue gas economizer 13 and an air duct economizer 23. Electric regulating valves 01 for the inlet water supply of the economizer are installed on the inlet header 41 of the flue gas economizer and the inlet header 51 of the air duct economizer, respectively. The outlet water temperature of the respective flue gas economizer outlet header 42 and the air duct economizer outlet header 52 is monitored. Under the premise of ensuring safety, the exhaust gas (flue gas, air) temperature can be appropriately adjusted by distributing the water supply flow.

[0080] The flue outlet ash hopper 85 and the air duct outlet ash hopper 95 are externally insulated. The flue outlet ash discharge valve 86 and the air duct outlet ash discharge valve 96 are installed below the ash hoppers to discharge the deposited particulate matter periodically.

[0081] All levels of heating equipment are highly integrated, and the modular design of the pipe box facilitates rapid on-site assembly.

[0082] In flue 10 and air duct 20, shock wave soot blowers 60 are installed in each level of heated equipment. The flue gas has a high dust content, while the air has a low dust content. They are blown regularly according to the different ash accumulation rates and degrees.

[0083] The working process for this application is as follows:

[0084] (1) Under rated operating conditions, in their respective channels, the boiler feedwater is heated by the economizer and enters the common boiler drum 31. The saturated water in the boiler drum 31 enters the flue evaporator 12 and the air evaporator 22 through the flue evaporator downcomer 48 and the air evaporator downcomer 58. The steam-water mixture after heat absorption returns to the boiler drum 31 through the evaporator outlet pipe under the circulation power generated by the gravity difference for steam-water separation. The separated saturated steam is heated by the low temperature section of the superheater in the two channels, the superheater spray water desuperheater spray water temperature control, and the superheater high temperature section reheated. The superheated steam is collected in the steam collector 32 and discharged to the steam turbine generator set.

[0085] (2) When the exhaust temperature of the heat transfer medium in one channel is too high, the water flow rate of the energy saver and the steam flow rate of the superheater can be appropriately increased. This can increase the heat transfer temperature difference and heat transfer coefficient between the energy saver and the superheater, improve the heat transfer capacity of the heated equipment, and thus reduce the exhaust temperature. At the same time, the exhaust temperature of the heat transfer medium in the other channel will increase, and vice versa.

[0086] (3) When the temperature of the superheated steam in one channel is too high and the amount of desuperheating spray is too large, the steam flow rate of the superheater can be appropriately increased to reduce the temperature of the superheated steam, prevent the superheater tube wall from overheating, and protect the safety of the superheater. At this time, the temperature of the superheated steam in the other channel will increase, and vice versa.

[0087] (4) When the flow rate of superheated steam in a channel decreases, the heat absorption of the superheater will decrease, the temperature of the heat transfer medium at the inlet of the evaporator will increase, the heat absorption of the evaporator will increase, and the saturated steam production will increase accordingly, and vice versa.

[0088] Compared with the prior art, the present invention has the following advantages:

[0089] 1. This application achieves the work that originally required two boilers (the waste heat boiler for flue gas extraction in the firing zone 102 and the waste heat boiler for air extraction in the cooling zone 103) with only one boiler, greatly simplifying the temperature control and waste heat utilization system of the tunnel kiln 100 and reducing project investment and operating costs.

[0090] 2. This application not only solves the problem that the temperature control of the tunnel kiln 100 is difficult to accurately control after the flue gas extracted from the firing zone 102 and the air extracted from the cooling zone 103 are premixed and then enter the waste heat boiler, which affects the quality of bricks, but also solves the problem that the mixed flue gas cannot be sent back to the tunnel kiln 100 for temperature control.

[0091] 3. The low-temperature hot air discharged from the waste heat boiler is returned to the tunnel kiln 100, which can reduce the amount of cold air supplied to the tunnel kiln 100, thereby reducing the amount of flue gas discharged from the system, reducing the construction investment and operating costs of the flue gas purification system, and also reducing the heat loss of flue gas and the amount of waste gas emissions, which is conducive to energy conservation and environmental protection.

[0092] 4. The heat-receiving equipment at each level in the two channels of the waste heat boiler is independent of each other but interconnected through system pipelines. By adjusting the working fluid flow rate, the heat release of the two heat transfer media (flue gas and air) is mutually supplemented and coordinated, which increases the means of boiler exhaust temperature regulation. It can achieve precise control of exhaust temperature without changing the air extraction volume, thereby ensuring the working temperature of the drying kiln and the 100°C air return temperature of the tunnel kiln, and improving the stability of brick quality.

[0093] 5. The heating equipment at each stage within the two channels of the waste heat boiler can be designed specifically for the different properties of the heat transfer media (flue gas and air). For example, the flue gas channel contains a lot of dust and is corrosive; therefore, a lower design flue gas velocity for its heating equipment can prevent wear, while a higher exhaust temperature is beneficial for corrosion prevention and further utilization in the drying kiln. The air channel contains less dust and is non-corrosive; therefore, a slightly higher design flue gas velocity for its heating equipment can enhance heat exchange, while a lower exhaust temperature can not only improve the thermal efficiency of the waste heat boiler but also facilitate temperature control in the return tunnel kiln 100.

[0094] 6. Because the flue gas contains a high concentration of SO2, if the exhaust gas temperature of the waste heat boiler is too low, the wall temperature of its flue gas economizer 13 will drop to the sulfuric acid dew point, causing low-temperature corrosion. For single-channel waste heat boilers, the exhaust gas temperature cannot be adjusted. However, for this application, the heat release of the flue gas can be reduced by decreasing the working fluid flow rate of its flue gas economizer 13 and flue gas superheater 11, thereby increasing the exhaust gas temperature and preventing low-temperature corrosion. The service life and safety of the equipment can be reliably guaranteed.

[0095] 7. When the heat transfer medium extraction rate and extraction temperature change, the relative stability of boiler steam parameters can be maintained through coordinated control of internal heat exchange between the two channels, thereby ensuring the stability and reliability of the steam turbine generator set.

[0096] 8. The waste heat boiler adopts a dual-channel design, and the heating equipment is designed specifically according to the properties of the heat transfer medium. This not only improves the reliability and thermal characteristics of the boiler, but also makes the boiler structure more compact, improves the utilization rate of steel, and saves construction costs.

[0097] 9. All heating equipment in both channels of the waste heat boiler adopts a modular tube box design, is assembled in the factory, and can be quickly installed on site, shortening the construction period. While ensuring project quality, it can also reduce installation and construction costs.

[0098] 10. The waste heat boiler adopts a dual-channel design. The heated equipment in the two channels can select different shock wave blowing frequencies for ash removal according to the difference in ash accumulation speed and degree, which helps to save energy and reduce operating costs.

[0099] 11. The flue evaporator 12 and the air duct evaporator 22 in the two channels of the waste heat boiler adopt independent natural circulation loops, which can avoid mutual influence between different loops and ensure the reliability of boiler hydrodynamics.

[0100] This application discloses a dual-channel, internally controlled waste heat power generation boiler for tunnel kilns. It achieves efficient and safe heat release of two different high-temperature heat transfer media (flue gas and air) within the boiler, ensuring that they are not mixed throughout the process and that each process remains independent. This reduces the workload that would normally require two waste heat boilers to a single boiler. Furthermore, by adjusting the flow rate of the working fluids in the interconnected heating equipment arranged in the two channels, and with the assistance of the induced draft fan, it achieves precise dual control over the exhaust temperature and flow rate of both heat transfer media. This invention not only features a compact boiler structure, simplifying existing boiler construction and reducing investment and operating costs, but also enables the two heat transfer media to complement each other during the heat conversion process within the furnace while operating independently. It maximizes the stability of boiler operating parameters during temperature control of the tunnel kiln 100, improving the safety and efficiency of the power generation system and achieving precise temperature control of the tunnel kiln 100, which is of great significance for improving brick quality.

[0101] Unlike traditional single-channel boilers, this type of boiler features completely independent channels for different high-temperature heat transfer media (flue gas and air), ensuring no mixing or mutual interference between the two. The heating equipment within each channel is both independent and interconnected. By regulating the flow rate of the working fluid inside the boiler, the discharge temperature of the waste heat boiler's heat transfer media can be controlled, thereby minimizing the impact on the tunnel kiln's production process and guaranteeing brick quality. Furthermore, the heating equipment in both channels can be precisely designed to address the different properties of the flue gas and air, focusing on wear resistance, corrosion prevention, ash accumulation prevention, and efficient heat transfer. This optimizes the boiler structure, optimizes the boiler layout, and reduces investment and operating costs while ensuring product quality and performance.

[0102] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. A dual-channel internally controlled tunnel kiln waste heat power generation boiler, characterized in that: Including a tunnel kiln (100); and a boiler arranged across the tunnel kiln (100); The boiler includes two parallel flue (10) and air duct (20), as well as a boiler drum (31) and steam collector (32) shared by the flue (10) and air duct (20). The flue (10) and the air duct (20) are respectively connected to different areas of the tunnel kiln (100) through pipes and extract the heat transfer medium in the corresponding areas; The flue (10) and the air duct (20) are provided with ash hoppers, multiple superheaters, multiple evaporators and multiple energy savers in sequence from the inflow to the outflow of the heat transfer medium; The multiple energy-saving devices in the flue (10) and air duct (20) are connected in series on the boiler drum (31) to form an energy-saving device regulation system; The multiple evaporators in the flue (10) and air duct (20) are connected in parallel to the boiler drum (31) through their respective pipes to form an evaporator regulation system; The multiple superheaters in the flue (10) and air duct (20) are connected in series between the boiler drum (31) and the steam collector (32) to form a superheater regulation system; The tunnel kiln (100) includes a preheating zone (101), a firing zone (102), and a cooling zone (103) that are continuously arranged. The flue (10) is connected to the firing zone (102) of the tunnel kiln (100) through a pipe and extracts high-temperature flue gas from the firing zone (102). The air duct (20) is connected to the cooling zone (103) of the tunnel kiln (100) through a pipe and extracts high-temperature air from the cooling zone (103). The corresponding ash hoppers in the flue (10) and the air duct (20) include an inlet ash hopper and an outlet ash hopper. The inlet ash hopper adopts an internal insulation method, and a corresponding inlet ash discharge valve is set below the inlet ash hopper. The deposited particles are discharged periodically. The outlet ash hopper adopts an external insulation method, and an outlet ash discharge valve is set below the ash hopper. The inlet ash hopper and the outlet ash hopper are respectively provided with heat transfer medium inlet and outlet. Both heat transfer medium outlets are connected to induced draft fans to transport the heat transfer medium to the drying kiln for deep utilization of waste heat. The heat transfer medium located in the air duct (20) can also be transported to the tunnel kiln (100) for recycling.

2. The dual-channel internally adjustable tunnel kiln waste heat power generation boiler as described in claim 1, characterized in that: The boiler adopts an inverted "U" shape structure and is arranged above the tunnel kiln (100). The flue (10) and air duct (20) also adopt an inverted "U" shape structure and are connected in the same boiler through a steel structure (70). The inlet and outlet of the flue (10) and air duct (20) are located below.

3. The dual-channel internally adjustable tunnel kiln waste heat power generation boiler as described in claim 1, characterized in that: The various types of heating equipment in the flue (10) and air duct (20) are arranged side by side, and each level of heating equipment is equipped with a shock wave soot blower (60). The heating equipment includes a superheater, an evaporator and an energy saver.

4. The dual-channel internally adjustable tunnel kiln waste heat power generation boiler as described in claim 3, characterized in that: The energy-saving device is equipped with an energy-saving device inlet header and an energy-saving device outlet header according to the water flow direction. At the same time, an energy-saving device outlet header thermocouple (03) is installed on the energy-saving device outlet header, and an energy-saving device inlet electric regulating valve (01) is installed on the water supply pipe of the energy-saving device inlet header.

5. A dual-channel internally adjustable tunnel kiln waste heat power generation boiler as described in claim 1, characterized in that: The number of evaporators in the flue (10) is greater than the number of evaporators in the air duct (20), that is, an evaporator is placed in front of the flue (10), and an evaporator inlet header and an evaporator outlet header are set on the evaporator according to the direction of water flow.

6. The dual-channel internally adjustable tunnel kiln waste heat power generation boiler as described in claim 1, characterized in that: The superheater is provided with a superheater inlet header and a superheater outlet header according to the steam flow direction. The pipe leading from the boiler drum (31) to the two superheater inlet headers is provided with a superheater steam inlet electric regulating valve (02). The steam collector (32) is provided with a steam collector thermocouple (06).

7. A dual-channel internally adjustable tunnel kiln waste heat power generation boiler as described in claim 6, characterized in that: The superheater inlet header is arranged on one side of the heat transfer medium inlet, and the superheater outlet header is arranged on the low temperature side of the heat transfer medium. A superheater spray desuperheater is installed between the low temperature section and the high temperature section of the superheater, and a desuperheater thermocouple (04) is installed at the steam inlet end and the steam outlet end of the superheater spray desuperheater, respectively. A superheater outlet header thermocouple (05) is also installed on the superheater outlet header.

8. A dual-channel internally adjustable tunnel kiln waste heat power generation boiler as described in claim 1, characterized in that: The evaporators are located at the rear end of the superheater, and each evaporator is connected to the boiler drum (31) through a separate evaporator outlet pipe, forming an independent natural circulation system.

Images