Coke oven top waste heat recovery system

Abstract

The present application relates to a coke oven top waste heat recovery system, comprising an upcomer heat exchanger arranged at the coke oven top, the upcomer heat exchanger having a heat exchange flow channel for passing raw coke oven gas; a top heat exchange pipe arranged at the position of clay brick layer or the position of heat insulation brick layer or between the two positions; the upcomer heat exchanger and the top heat exchange pipe are connected together in parallel, in series or in a combination of series and parallel. The coke oven top waste heat recovery system removes part of heat through the top heat exchange pipe, and the heat transferred from the heat insulation brick to the surface of the coke oven top is reduced, so that the heat loss of the coke oven is reduced, and the temperature of the top operating surface is reduced. On the other hand, the top heat exchange pipe is connected with the upcomer heat exchanger in parallel or in series, and the heat exchange medium (desalted water) is partially vaporized by absorbing heat in the top heat exchange pipe, so that the steam generation is increased, the heat loss of the top of the coke oven can be reduced by 60%, and the total steam production can be increased by 30% compared with the upcomer heat exchanger alone.

Description

Technical Field

[0001] This invention relates to the field of coking oven equipment technology, and in particular to a coking oven top waste heat recovery system. Background Technology

[0002] A coke oven, also known as a coking furnace, is the main thermal equipment used to convert coal into coke. Coke and coking gas are its main energy products, and efficient recovery of waste heat generated during the coking process is one of the main ways to reduce coke oven energy consumption. The intermediate-temperature waste heat from raw coke oven gas accounts for about 36% of the entire coking process, indicating significant potential for utilization. Among these, the riser heat exchanger is the main equipment for waste heat recovery in coking production. It can both transport raw coke gas and exchange heat, absorbing waste heat from the raw coke gas within the riser for recovery and utilization. This is disclosed in patent application CN201610642287.7, "Coke Oven Raw Coke Gas Waste Heat Recovery and Utilization System."

[0003] However, current waste heat recovery methods in coking production only recover heat from raw coal gas through riser heat exchangers, resulting in limited heat recovery capacity. Furthermore, heat loss from the coking oven surface accounts for 10% of the total heat output, with the top accounting for more than half of this loss. Currently, there is no relatively effective technology to recover this portion of heat. This heat loss from the oven top not only wastes energy but also exposes the top to a harsh, high-temperature environment, with the average surface temperature of the coking oven top reaching over 70°C.

[0004] Therefore, the existing coke oven top waste heat recovery system still needs further improvement. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a coke oven top waste heat recovery system that can effectively recover heat from the top of the furnace, reduce heat loss from the top of the furnace, lower the temperature of the top of the coke oven, and improve the working environment of the top of the furnace, in light of the current state of the technology.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a coke oven top waste heat recovery system, including a riser heat exchanger installed on the top of the coke oven. The riser heat exchanger has a heat exchange channel for raw coal gas to pass through, a first medium inlet for heat exchange medium to enter therein, and a first medium outlet for heat exchanged medium to flow out. The coke oven top includes a clay brick layer and a heat insulation brick layer.

[0007] The furnace top heat exchange tube is arranged at the location of the clay brick layer or the location of the insulation brick layer or between the clay brick layer and the insulation brick layer. The furnace top heat exchange tube has a second medium inlet for the heat exchange medium to enter and a second medium outlet for the medium after heat exchange to flow out.

[0008] The riser heat exchanger and the furnace top heat exchange tube are connected in parallel, in series, or in a combination of series and parallel.

[0009] As an improvement, the second medium outlet of the furnace top heat exchange tube is connected to the first medium inlet of the riser heat exchanger, thereby connecting the riser heat exchanger and the furnace top heat exchange tube in series; or

[0010] The second medium inlet of the furnace top heat exchange tube is connected to the first medium inlet of the riser heat exchanger, and the second medium outlet of the furnace top heat exchange tube is connected to the first medium outlet of the riser heat exchanger, thereby connecting the riser heat exchanger and the furnace top heat exchange tube in parallel.

[0011] As an improvement, the furnace top heat exchange tubes and riser heat exchangers connected in series together form a first heat exchanger group.

[0012] The coke oven top waste heat recovery system includes at least two first heat exchanger groups, and each first heat exchanger group is connected in parallel.

[0013] As an improvement, there are at least two riser heat exchangers, and at least two riser heat exchangers connected in parallel together constitute a riser heat exchanger group.

[0014] The furnace top heat exchange tubes are at least two, and the at least two furnace top heat exchange tubes connected in parallel together form a furnace top heat exchange tube group.

[0015] The riser heat exchanger assembly is connected in parallel with the furnace top heat exchanger assembly.

[0016] In order to recover heat from the entire area at the top of the coke oven, the coke oven includes a carbonization chamber and a combustion chamber, and the heat exchange tubes at the top of the furnace are arranged in a circuitous manner at the top of the carbonization chamber and the combustion chamber.

[0017] As an improvement, the heat exchange medium is demineralized water.

[0018] To perform deoxygenation on the demineralized water, a deaerator and a steam drum are also included. The deaerator is connected to a first demineralized water delivery pipeline for conveying demineralized water. The deaerator is connected to the liquid inlet of the steam drum through a second demineralized water delivery pipeline. The steam drum is connected to the second medium inlet of the furnace top heat exchange tube and / or the first medium inlet of the riser heat exchanger through a third demineralized water delivery pipeline.

[0019] The second medium outlet of the furnace top heat exchange tube and / or the first medium outlet of the riser heat exchanger are connected to the steam inlet of the steam drum.

[0020] The steam drum's outlet is also connected to a steam output pipeline for transporting steam downstream.

[0021] In order to use the generated steam to thermally deoxygenate the demineralized water and improve the deoxygenation effect, the steam drum is also connected to the deaerator through a deoxygenated steam pipeline.

[0022] In order to perform timely descaling and drainage of the steam drum, the steam drum is also connected to a chemical dosing pipeline and a drainage pipeline.

[0023] To effectively eliminate vibration problems caused by water flow impact and reduce temperature difference stress caused by temperature fluctuations, thereby extending the service life of the riser heat exchanger, the riser heat exchanger includes:

[0024] The cylindrical body has a hollow interior forming a channel;

[0025] The heat exchange coil is installed in the channel of the cylinder and is arranged in a spiral shape along the extension direction of the channel. An installation gap is reserved between any two adjacent layers of the heat exchange coil.

[0026] The arc plate support assembly includes a first arc plate and a second arc plate, both arranged spirally along the extension direction of the channel. The cross-sections of the first arc plate and the second arc plate are both C-shaped. The orientation of the C-shaped opening of the first arc plate is opposite to that of the C-shaped opening of the second arc plate. Both are arranged together in the installation gap of the heat exchange coil and simultaneously support the two adjacent layers of the heat exchange coil.

[0027] A ceramic coating is applied to the side of the heat exchange coil and the arc plate support assembly facing the center of the cylinder. The internal space enclosed by the ceramic coating forms a heat exchange channel for the raw coal gas to pass through.

[0028] Because the heat exchange tubes at the top of the furnace are embedded in the insulating bricks, they are difficult to inspect and maintain during normal operation. To prevent damage to the coke oven body from water leakage due to rupture of the heat exchange tubes, the heat exchange tubes at the top of the furnace include an inner tube for transporting the heat exchange medium and an outer tube sleeved outside the inner tube. The inner wall of the outer tube has at least one drainage groove along its length, and a leak detection tube connected to the drainage groove is also attached to the outer tube. During normal operation, the inner tube of the heat exchange tube at the top of the furnace does not leak, and no water vapor flows out of the leak detection tube. If the inner tube of the heat exchange tube at the top of the furnace ruptures or leaks, the leaked water and steam will collect through the drainage groove and flow out through the leak detection tube, allowing for timely detection during inspections.

[0029] To improve the accuracy of leak detection of the furnace top heat exchange tube, there are four drainage channels, which are arranged sequentially at intervals along the circumference of the outer tube. There are also four corresponding leak detection tubes, which are connected to each of the drainage channels.

[0030] Compared with existing technologies, the advantages of this invention are as follows: The coke oven top waste heat recovery system of this invention removes some heat through the top heat exchange tubes, reducing the heat transferred from the insulating bricks to the top surface, thereby reducing heat loss from the coke oven and lowering the temperature of the operating surface at the top. Furthermore, the top heat exchange tubes are connected in parallel or series with the riser heat exchangers. The heat exchange medium (demineralized water) absorbs heat and partially vaporizes within the top heat exchange tubes, increasing steam generation. Through heat transfer calculations, after arranging a certain density of top heat exchange tubes, heat loss at the top can be reduced by 60%, the top surface temperature can be reduced to below 40°C, and the total steam production can be increased by 30% compared to using a riser heat exchanger alone. The coke oven top waste heat recovery system of this invention effectively reduces heat loss at the top, lowers the temperature at the top of the coke oven, and improves the working environment at the top. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the coke oven top waste heat recovery system according to an embodiment of the present invention;

[0032] Figure 2 This is a flowchart of the coke oven top waste heat recovery system according to an embodiment of the present invention;

[0033] Figure 3 This is a flowchart of the coke oven top waste heat recovery system according to an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the structure of the riser heat exchanger according to an embodiment of the present invention;

[0035] Figure 5 for Figure 4 Enlarged view of point A in the middle.

[0036] Figure 6 This is a cross-sectional view of the furnace top heat exchange tube according to an embodiment of the present invention. Detailed Implementation

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0038] The specification and claims of this invention use terms indicating direction, such as "front," "rear," "upper," "lower," "left," "right," "side," "top," and "bottom," to describe various exemplary structural parts and elements of the invention. However, these terms are used herein merely for ease of explanation and are determined based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed in this invention can be arranged in different orientations, these terms indicating direction are for illustrative purposes only and should not be considered as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

[0039] See Figures 1-6A coke oven top waste heat recovery system includes a top heat exchange tube 60, a riser heat exchanger 1, a deaerator 81, and a steam drum 82.

[0040] See Figure 1 A coke oven typically includes dozens of alternating combustion chambers (a) and carbonization chambers (b), separated by furnace walls. Combustion chambers (a) have several observation holes (2) on their tops for easy observation and temperature measurement. Carbonization chambers (b) have coal charging holes (3) and raw coal gas outlets on their tops, which are directly connected to riser heat exchangers (1). Heat exchange tubes (60) are arranged in a circuitous pattern on the tops of carbonization chambers (b) and combustion chambers (a), thereby recovering heat from the entire top area of ​​the coke oven. Specifically, along the heat dissipation path (generally from bottom to top), the top of the coke oven consists of a refractory brick layer, a clay brick layer, insulating bricks, and molten bricks. In this embodiment, the heat exchange tubes (60) can be laid horizontally at the location of the clay brick layer, the location of the insulating brick layer, or between the clay brick layer and the insulating brick layer. Preferably, in this embodiment, the heat exchange tubes (60) are positioned in a groove opened in the upper part of the insulating brick layer. The furnace top heat exchange tube 60 has a second medium inlet 601 for the heat exchange medium to enter and a second medium outlet 602 for the medium to flow out after heat exchange.

[0041] The riser heat exchanger 1 is also installed at the top of the coke oven to draw out the raw coal gas generated in the coke oven. Correspondingly, the riser heat exchanger 1 has a heat exchange channel for the raw coal gas to pass through. The riser heat exchanger 1 can be a coil-type heat exchanger, which has a first medium inlet for the heat exchange medium to enter and a first medium outlet for the medium to flow out after heat exchange. The specific structure of the riser heat exchanger 1 is described below.

[0042] In this embodiment, the riser heat exchanger 1 and the furnace top heat exchange tube 60 can be connected in parallel, in series, or in a combination of series and parallel.

[0043] The heat exchange medium used to recover heat from the furnace top and the sensible heat of the raw coal gas is demineralized water. Deaerator 81 is connected to a first demineralized water delivery pipeline 91 for conveying demineralized water. Deaerator 81 is connected to the inlet of steam drum 82 via a second demineralized water delivery pipeline 92, on which a first pump 83 is installed. Steam drum 82 is connected to the second medium inlet 601 of the furnace top heat exchange tube 60 and / or the first medium inlet of the riser heat exchanger 1 via a third demineralized water delivery pipeline 93, on which a second pump 84 is installed. The second medium outlet 602 of the furnace top heat exchange tube 60 and / or the first medium outlet of the riser heat exchanger 1 are connected to the steam inlet of steam drum 82. The steam outlet of steam drum 82 is also connected to a steam output pipeline 97 for conveying steam downstream, a chemical dosing pipeline 95, and a blowdown pipeline 96. Steam drum 82 is also connected to deaerator 81 via a deaerated steam pipeline 94.

[0044] Demineralized water from outside the boundary is sent to deaerator 81 via the first demineralized water delivery pipeline 91. It undergoes thermal deoxygenation via steam output from steam drum 82. The deaerator 81 operates at a pressure of approximately 0.02 MPaG and a temperature of 102℃~104℃. The generated deoxygenated water is then sent to steam drum 82 via the first pump 83 (deoxygenated water pump) on the second demineralized water delivery pipeline 92. Water in steam drum 82 is then pumped by the second pump 84 (forced circulation pump) via the third demineralized water delivery pipeline 93 to multiple sets of furnace top heat exchange tubes 60 and riser heat exchangers 1. The furnace top heat exchange tubes 60 and riser heat exchangers 1 can be connected in parallel or in series.

[0045] Inside the furnace top heat exchange tube 60, the demineralized water absorbs heat from the clay bricks or insulating bricks at 200–600°C, partially vaporizing. In the riser heat exchanger 1, the raw coal gas flows from bottom to top, and the demineralized water also flows from bottom to top, exchanging heat in a co-current manner. The water in the heat exchanger coils absorbs heat and partially vaporizes. The resulting steam-water mixture enters the steam drum 82 for gas-liquid separation, ultimately producing saturated steam of 0.5–4.0 MPaG. Part of the steam is sent to the deaerator 81 via the deaerator steam pipeline 94 for deoxygenation of the demineralized water, while the remainder is sent downstream as steam product via the steam output pipeline 97.

[0046] After the raw gas temperature is cooled from 550-850℃ to 450-480℃ by the riser heat exchanger, the temperature of the raw gas at the center and wall of the outlet of the riser heat exchanger 1 is controlled to be no lower than 450℃ to prevent the accumulation of tar and other components and to avoid reducing the yield of chemical products.

[0047] Inside the steam drum 82, water evaporates and vaporizes, concentrating the salt content. To prevent scaling and equipment corrosion, phosphate is added through the dosing pipeline 95, causing phosphate ions to combine with calcium and magnesium ions in the water to form precipitates. At the same time, a drain pipeline 96 is installed to clean the salt and precipitates inside the steam drum 82, controlling the blowdown rate of the steam drum 82 to ≤2%.

[0048] Numerous riser heat exchangers 1 are connected in parallel. In conventional riser waste heat recovery systems, the piping is arranged symmetrically in a stepped manner, with 4 to 9 riser heat exchangers 1 sharing a single water supply pipe. A high-flow-rate forced circulation pump and a segmented piping network layout ensure a relatively uniform water inflow to each riser heat exchanger 1. However, coke oven production is intermittent. Each carbonization chamber undergoes processes such as coal charging, dry distillation, coking, and coke pushing. During these processes, the temperature, volume, and composition of the raw coal gas change, and different coke pushing sequences are in different production processes. Therefore, the gas production rate of the riser heat exchangers 1 varies continuously over time, and the gas production rates of riser heat exchangers 1 in different coke pushing sequences are not synchronized. Therefore, the conventional method of uniformly controlling the water inlet flow of the riser heat exchanger 1 cannot adjust the water inlet flow according to the operating conditions of each riser heat exchanger 1. As a result, the temperature of the raw coal gas at the outlet of the riser heat exchanger 1 cannot be accurately controlled. A high raw coal gas outlet temperature will lead to a decrease in waste heat recovery efficiency; an outlet temperature below 450℃ will lead to tar accumulation and a decrease in chemical product yield.

[0049] To specifically adjust the water inlet flow rate of each riser heat exchanger 1, the coke oven top waste heat recovery system in this embodiment is equipped with an independent pneumatic or electric regulating valve and flow meter on the water supply pipe of each riser heat exchanger. Since the temperature, flow rate, and composition curves of the raw coal gas generated in the coking chamber remain relatively stable over time during the intermittent coking cycle, the water inlet regulating valve of each riser heat exchanger 1 can be automatically adjusted via a DCS or PLC system based on the coking time and the temperature parameters of the raw coal gas entering and exiting the riser heat exchanger 1. This accurately controls the water inlet flow rate of a single riser heat exchanger 1, thereby accurately regulating the temperature of the raw coal gas at the outlet of the riser heat exchanger 1, improving the waste heat recovery efficiency of the raw coal gas, preventing the outlet temperature of the raw coal gas from being too low and causing tar accumulation, and avoiding mutual interference between the water inlets of different riser heat exchangers. Furthermore, the water supply pipe flow meter is equipped with a low flow alarm to prevent the heat exchanger from dry burning.

[0050] See Figure 2 In this embodiment, the second medium outlet 602 of the furnace top heat exchange tube 60 is connected to the first medium inlet of the riser heat exchanger 1, thereby connecting the riser heat exchanger 1 and the furnace top heat exchange tube 60 in series. The furnace top heat exchange tube 60 and the riser heat exchanger 1 connected in series together constitute a first heat exchanger group 71. Multiple first heat exchanger groups 71 can be provided and connected in parallel.

[0051] See Figure 3The invention discloses that the riser heat exchanger 1 and the furnace top heat exchange tube 60 are connected in parallel. Specifically, there are multiple riser heat exchangers 1, which together form a riser heat exchanger group 72. Similarly, there are multiple furnace top heat exchange tubes 60, which together form a furnace top heat exchange tube group 73. The riser heat exchanger group 72 and the furnace top heat exchange tube group 73 are connected in parallel, that is, the first medium inlet of each riser heat exchanger 1 in the riser heat exchanger group 72 and the second medium inlet 601 of each furnace top heat exchange tube 60 in the furnace top heat exchange tube group 73 share the same water supply pipeline, and the first medium outlet of each riser heat exchanger 1 in the riser heat exchanger group 72 and the second medium outlet 602 of each furnace top heat exchange tube 60 in the furnace top heat exchange tube group 73 share the same water outlet pipeline.

[0052] See Figure 4 and Figure 5 A riser heat exchanger includes a cylinder 10, an insulation layer 13, a heat exchange coil 20, an arc plate support assembly 30, and a ceramic coating 40.

[0053] The cylindrical body 10 is vertically oriented and has a hollow interior forming a channel 11. This channel 11 houses the aforementioned insulation layer 13, heat exchange coil 20, arc-shaped plate support assembly 30, and ceramic coating 40. In this embodiment, the cylindrical body 10 is made of metal and has at least one expansion joint 12 along its axial direction to prevent damage due to thermal stress. The channel 11 of the cylindrical body 10 has two opposing ports in the vertical direction.

[0054] The heat exchange coil 20 is disposed inside the cylinder 10 and arranged spirally along the extension direction of the channel 11. Figure 1 As can be seen, the axial length of the spiral heat exchange coil 20 in this embodiment is basically the same as the length of the cylinder 10. The lower end of the heat exchange coil 20 protrudes beyond the bottom of the peripheral wall of the cylinder 10 as a water inlet 24 (i.e., the first medium inlet), and the upper end of the heat exchange coil 20 also protrudes beyond the top of the peripheral wall of the cylinder 10 as a water vapor outlet 25 (i.e., the first medium outlet). An installation gap 26 is reserved between any two adjacent layers on the spiral heat exchange coil 20, such as... Figure 5 The upper pipe fitting 21 and the lower pipe fitting 22 of the heat exchange coil 20 shown in the figure form an installation gap 26. From the overall structure of the heat exchange coil 20, the installation gaps 26 are of the same size and are connected in sequence, which also forms an installation gap 26 that is also arranged in a spiral shape.

[0055] The heat exchange coil 20 in this embodiment can be made of low-carbon carbon steel or heat-resistant steel, such as ferritic heat-resistant steel, pearlitic heat-resistant steel, martensitic heat-resistant steel, or austenitic heat-resistant steel. The heat exchange coil 20 uses thick-walled, high-pressure resistant pipes, which have high rigidity and strength, preventing metal creep caused by large temperature fluctuations during operation, and can produce medium-pressure steam above 2.5 MPa.

[0056] The arc-shaped plate support assembly 30 is also spiral-shaped and is correspondingly disposed in the spiral mounting gap 26 of the heat exchange coil 20 to provide overall support for the heat exchange coil 20. Specifically, the arc-shaped plate support assembly 30 includes a first arc-shaped plate 31 and a second arc-shaped plate 32, wherein both the first arc-shaped plate 31 and the second arc-shaped plate 32 are spirally arranged along the extension direction of the channel 11. The cross-sections of the first arc-shaped plate 31 and the second arc-shaped plate 32 are both C-shaped. The first arc-shaped plate 31 has a first sidewall 311 facing the opening and a second sidewall 312 away from the opening, and also has opposing first sidewalls 313 and second sidewalls 314. The second arc-shaped plate 32 has a third sidewall 321 facing the opening and a fourth sidewall 322 away from the opening, and also has opposing third sidewalls 323 and fourth sidewalls 324. In this embodiment, the first arc-shaped plate 31 and the second arc-shaped plate 32 have basically the same structure and dimensions. The second arc-shaped plate 32 is located on the side of the first arc-shaped plate 31 away from the cylinder 10. Furthermore, the second sidewall 312 of the first arc-shaped plate 31 and the fourth sidewall 322 of the second arc-shaped plate 32 are opposite to each other. That is, the first sidewall 311 of the first arc-shaped plate 31 faces outward along the radial direction of the cylinder 10, the second sidewall 312 faces inward along the radial direction of the cylinder 10, the third sidewall 321 of the second arc-shaped plate 32 faces inward along the radial direction of the cylinder 10, and the fourth sidewall 322 faces outward along the radial direction of the cylinder 10. More specifically, the first side 313 and the second side 314 of the first arc-shaped plate 31 are respectively welded to the tube walls of two adjacent layers of coils on the heat exchange coil 20, and the third side 323 and the fourth side 324 of the second arc-shaped plate 32 are also respectively welded to the tube walls of two adjacent layers of coils on the heat exchange coil 20. Figure 5 As shown, the first side 313 of the first arc-shaped plate 31 and the third side 323 of the second arc-shaped plate 32 are located on the same side, supporting the bottom of the upper pipe fitting 21. The second side 314 of the first arc-shaped plate 31 and the fourth side 324 of the second arc-shaped plate 32 are located on the same side, supporting the top of the lower pipe fitting 22. To further ensure the support strength of the arc-shaped plate support assembly 30 for the heat exchange coil 20, in this embodiment, the second side wall 312 of the first arc-shaped plate 31 abuts against the fourth side wall 322 of the second arc-shaped plate 32.

[0057] The ceramic coating 40 is specifically applied to the third sidewall 321 of the second arc-shaped plate 32 and to the side of the heat exchange coil 20 facing the center of the cylinder 10. The internal space enclosed by the ceramic coating 40 forms a heat exchange channel 41 through which raw coal gas passes. The lower end of the heat exchange channel 41 forms the raw coal gas inlet 42, and the upper end forms the raw coal gas outlet 43, through which the raw coal gas flows out after heat exchange. The raw coal gas inlet 42 is connected to the coke oven body via a flange, and the raw coal gas outlet 43 is connected to the downstream raw coal gas pipeline via a flange.

[0058] See Figure 2 The side edge of the third sidewall 321 of the second arc-shaped plate 32 smoothly transitions into the tube wall of the heat exchange coil 20, resulting in a wavy cross-section of the ceramic coating 40 applied to the tube wall of the heat exchange coil 20 and the third sidewall 321 of the second arc-shaped plate 32 along the extension direction of the cylinder 10. Specifically, the radius of curvature of the second arc-shaped plate 32 is basically the same as the radius of curvature of the heat exchange coil 20, thus the cross-section of the ceramic coating 40 along the extension direction of the cylinder 10 is sinusoidal. The portion of the ceramic coating 40 located on the third sidewall 321 of the second arc-shaped plate 32 and the portion of the ceramic coating located on the tube wall of the heat exchange coil 20 correspond to the peaks and troughs of the sine wave, respectively. The cross-sectional shape of the heat exchanger inner wall (i.e., the ceramic coating 40) is a sinusoidal structure with no sharp-angle dead zones, preventing tar from accumulating in the dead zones. On the other hand, through flow field simulation, compared with the planar structure of the inner wall of a conventional water-jacketed heat exchanger, the sinusoidal structure inside the heat exchanger of this invention causes the flow pattern of raw coal gas to change from laminar to turbulent when it passes through, which greatly improves its heat transfer coefficient. Since the coil can withstand higher pressure than the jacket, the steam pressure produced by the heat exchanger in this embodiment is higher than that of the water-jacketed type.

[0059] In this embodiment, the thickness of the ceramic coating 40 is 0.01 mm to 5 mm, preferably 0.1 mm to 1 mm. The relatively small thickness of the ceramic coating 40 means that the heat exchange coil 20 is in direct contact with the raw coal gas. Compared to an external coil heat exchanger, this results in lower metal thermal resistance and better heat exchange performance.

[0060] The insulation layer 13 is affixed to the inner wall of the cylinder 10, specifically wrapping around the heat exchange coil 20 and the arc plate support assembly 30 to reduce heat loss through outward transfer. The side of the heat exchange coil 20 facing the cylinder 10 is in contact with the insulation layer 13, and the third sidewall 321 of the first arc plate 31 of the arc plate support assembly 30 is also in contact with the insulation layer 13.

[0061] There is a gap 23 between the first arc-shaped plate 31, the second arc-shaped plate 32, and the tube wall of the heat exchange coil 20. To prevent pressure changes caused by temperature rise inside the gap 23, a vent hole 52 is provided on the riser heat exchanger, extending from the cylinder 10 to the gap 23. Figure 4 As shown, there are two vent holes 52, located near the upper and lower ends of the cylinder 10, respectively. These vent holes 52 serve a leak detection function. When the second arc-shaped plate 32 is damaged, or the weld between the second arc-shaped plate 32 and the heat exchange coil 20 is damaged, raw coal gas leaks into the installation gap 26. Yellow raw coal gas smoke can be observed through the vent holes 52, allowing for timely detection during manhole inspections. When the heat exchange coil 20 ruptures, water vapor leaks into the installation gap 26 and is discharged through the vent holes 52, also allowing for timely detection during manual inspections.

[0062] The riser heat exchanger also has temperature measuring holes 51a and 51b at positions corresponding to the installation gap 26 of the heat exchange coil 20. These temperature measuring holes 51a and 51b extend from the outer wall of the cylinder 10 (passing sequentially through the insulation layer 13, the second arc-shaped plate 32, and the first arc-shaped plate 31) into the heat exchange flow channel 41 within the ceramic coating 40. The large spacing between adjacent sections of the heat exchange coil 20, i.e., the existence of the installation gap 26, allows the riser heat exchanger to easily have temperature measuring holes 51a and 51b at any desired location and to install temperature measuring devices.

[0063] See Figure 4 The riser heat exchanger has multiple temperature measuring holes 51a and 51b along its length for installing online temperature sensing elements to accurately measure the temperature of the raw coal gas inside the heat exchanger. The multiple temperature measuring holes 51a and 51b are a central temperature measuring hole 51a and a wall temperature measuring hole 51b, respectively. The central temperature measuring hole 51a is located near the central axis of the heat exchanger and is used to measure the temperature of the raw coal gas at the center of the riser heat exchanger. The wall temperature measuring hole 51b is located near the inner wall of the heat exchanger and is used to measure the temperature of the raw coal gas near the wall. This allows for real-time monitoring to ensure that the temperature of the raw coal gas at the wall is not below 450℃, preventing the accumulation of tar and other components. Simultaneously, the temperature difference between the central temperature measuring hole 51a and the wall temperature measuring hole 51b can be used to monitor the turbulence effect of the raw coal gas inside the riser; a smaller temperature difference between the center and the wall indicates a better turbulence effect.

[0064] The advantages of the riser heat exchanger in this embodiment are as follows: 1. The arc plate support assembly 30 is welded to the heat exchange coils 20 above and below it, connecting the entire heat exchange coil 20 into a whole. Since the arc plate structure has flexibility and buffering properties, it can stabilize the entire heat exchange coil 20, greatly reduce the vibration caused by the impact of water flow on the heat exchange coil 20, and prevent the heat exchange coil 20 from being damaged. 2. The riser heat exchanger incorporates an arc-shaped plate support assembly 30 within the installation gap 26 between adjacent layers of the heat exchange coil 20. Due to the inherent structural characteristics of the arc-shaped plate support assembly 30 (using two arc-shaped plates arranged in opposite directions to simultaneously support adjacent layers of the heat exchange coil 20), it possesses a certain degree of flexibility (similar to the function of a metal expansion joint 12), allowing for axial expansion and contraction. This effectively compensates for the thermal expansion differences caused by varying metal wall temperatures in different parts of the heat exchanger, reduces thermal stress, prevents heat exchanger damage caused by deformation due to temperature differences and fluctuations, and eliminates the risk of water leakage from the riser heat exchanger into the carbonization chamber, thus preventing damage to the coke oven walls. 3. The arc-shaped plate support assembly 30 welded to the heat exchange tubes (especially the second arc-shaped plate 32 used for coating the ceramic coating 40) provides a fin-like enhanced heat transfer effect during heat exchange, improving the overall heat exchange efficiency of the riser. The ceramic coating 40 inside the heat exchanger is applied to the side of the heat exchange coil 20 and the arc plate support assembly 30 facing the center of the cylinder 10. This is equivalent to the heat exchange coil 20 directly exchanging heat with the raw coal gas. Compared with the external coil heat exchanger in the prior art, it has a lower metal thermal resistance. Compared with the internal coil heat exchanger and the insertion heat exchanger, its contact area with the raw coal gas is smaller (only the side of the heat exchange coil 20 facing the center of the cylinder 10 exchanges heat with the raw coal gas). The huge temperature fluctuations of the raw coal gas have a smaller impact on the heat exchange coil 20. At the same time, the ceramic coating 40 can both repel oil and self-clean, avoid tar coking and adhesion, and reduce the thermal resistance of dirt. It can also prevent the heat exchange coil 20 from directly contacting the raw coal gas, preventing the corrosion of the heat exchange coil 20 by tar, ammonia, hydrogen sulfide and other substances in the raw coal gas, as well as the alternating oxidizing and reducing atmospheres from damaging the strength of the heat exchange coil 20. 4. Utilizing the arc-shaped structure of the second arc-shaped plate 32 and the wall of the heat exchange coil 20, the cross-section of the ceramic coating 40 applied to the heat exchange coil 20 and the second arc-shaped plate 32 is wavy. This changes the flow state of the raw coal gas in the heat exchange channel 41 from laminar to turbulent, greatly increasing the heat transfer coefficient and improving the heat transfer effect. In particular, the sinusoidal ceramic coating 40 has no sharp-angle dead zones, which can effectively prevent tar from accumulating in the dead zones. 5. Under the support of the arc-shaped plate support assembly 30, there is a relatively large gap between adjacent sections of the heat exchange coil 20 (i.e., installation gap 26), so temperature measuring devices can be easily installed at any required location.

[0065] Because the furnace top heat exchange tubes are embedded in the insulating bricks, they are difficult to inspect and maintain during normal operation. To prevent the furnace top heat exchange tubes from rupturing and leaking water, which could damage the coke oven body, the furnace top heat exchange tube 60 in this embodiment consists of a double-layer pipe, an inner tube 62 and an outer tube 61. To enhance the heat exchange effect, the gap between the two layers of pipes does not exceed 5mm. The inner tube 62 is a water flow channel, and there is normally no flow between the outer tube 61 and the inner tube 62. At least one drainage channel can be opened on the inner side of the outer tube 61. At the second medium inlet 601, the drainage channel is connected to a leak detection pipe. During normal operation, the inner tube of the furnace top heat exchange tube does not leak water, and no water vapor flows out of the leak detection pipe. When the inner tube leaks, the leaked water and steam are collected through the drainage channel and flow out through the leak detection pipe, which can be detected in time during inspection.

[0066] In this embodiment, multiple drainage channels are provided along the circumference of the outer tube, through... Figure 6 As can be seen, there are four drainage channels, evenly spaced along the circumference of the outer pipe. Specifically, these include the first drainage channel 63a and the second drainage channel 63b located on the left and right sides of the outer pipe, and the third drainage channel 63c and the fourth drainage channel 63d located on the top and bottom sides of the outer pipe. These four drainage channels divide the outer circumference of the inner pipe into four areas, allowing the location of the leak to be determined based on the amount of water or steam leaking from the drainage channels. There are also 1-4 corresponding leak detection pipes: the first leak detection pipe 64a connected to the first drainage channel 63a, the second leak detection pipe 64b connected to the second drainage channel 63b, the third leak detection pipe 64c connected to the third drainage channel 63c, and the fourth leak detection pipe 64d connected to the fourth drainage channel 63d.

[0067] If water or steam is detected in the leak detection tube during operation, it can be determined that a leak has occurred in the inner tube. This allows maintenance personnel to quickly pinpoint the area requiring repair, greatly improving the efficiency of the maintenance work and preventing the leak from affecting the coke oven itself.

Claims

1. A coke oven top waste heat recovery system, comprising a riser heat exchanger (1) installed on the top of the coke oven, the riser heat exchanger (1) having a heat exchange channel for raw coal gas to pass through, a first medium inlet (24) for heat exchange medium to enter therein, and a first medium outlet (25) for heat exchanged medium to flow out, the coke oven top comprising a clay brick layer and a heat insulation brick layer. Its features Also includes: The furnace top heat exchange tube (60) is arranged at the location of the clay brick layer or the location of the insulation brick layer or between the clay brick layer and the insulation brick layer. The furnace top heat exchange tube (60) has a second medium inlet (601) for the heat exchange medium to enter and a second medium outlet (602) for the medium after heat exchange to flow out. The riser heat exchanger (1) and the furnace top heat exchange tube (60) are connected in parallel, in series, or in a combination of series and parallel. The riser heat exchanger (1) includes: The cylindrical body (10) has a hollow interior forming a channel (11); The heat exchange coil (20) is installed in the channel (11) of the cylinder (10) and is arranged in a spiral shape along the extension direction of the channel (11). An installation gap (26) is reserved between any two adjacent layers of the heat exchange coil (20). The arc plate support assembly (30) includes a first arc plate (31) and a second arc plate (32) that are spirally arranged along the extension direction of the channel (11). The cross-sections of the first arc plate (31) and the second arc plate (32) are both C-shaped. The orientation of the C-shaped opening of the first arc plate (31) is opposite to that of the C-shaped opening of the second arc plate (32). Both are arranged together in the installation gap (26) of the heat exchange coil (20) and simultaneously support the two adjacent layers of the heat exchange coil (20). A ceramic coating (40) is applied to the side of the heat exchange coil (20) and the arc plate support assembly (30) facing the center of the cylinder (10). The internal space enclosed by the ceramic coating (40) forms a heat exchange channel (41) through which raw coal gas passes. The second arc plate (32) has a third sidewall (321) facing the opening and a fourth sidewall (322) facing away from the opening. The side edge of the third sidewall (321) of the second arc plate (32) smoothly transitions to the tube wall of the heat exchange coil (20), so that the cross section of the ceramic coating (40) coated on the tube wall of the heat exchange coil (20) and the third sidewall (321) of the second arc plate (32) along the extension direction of the cylinder (10) is wavy.

2. The coke oven top waste heat recovery system according to claim 1, characterized in that: The second medium outlet (602) of the furnace top heat exchange tube (60) is connected to the first medium inlet (24) of the riser heat exchanger (1), thereby connecting the riser heat exchanger (1) and the furnace top heat exchange tube (60) in series; or The second medium inlet (601) of the furnace top heat exchange tube (60) is connected to the first medium inlet (24) of the riser heat exchanger (1), and the second medium outlet (602) of the furnace top heat exchange tube (60) is connected to the first medium outlet (25) of the riser heat exchanger (1), thereby connecting the riser heat exchanger (1) and the furnace top heat exchange tube (60) in parallel.

3. The coke oven top waste heat recovery system according to claim 2, characterized in that: The furnace top heat exchange tube (60) and the riser heat exchanger (1) connected in series together form a first heat exchanger group (71); The coke oven top waste heat recovery system includes at least two first heat exchanger groups (71), and each first heat exchanger group (71) is connected in parallel.

4. The coke oven top waste heat recovery system according to claim 2, characterized in that: There are at least two riser heat exchangers (1), and at least two riser heat exchangers (1) connected in parallel together constitute a riser heat exchanger group (72). There are at least two furnace top heat exchange tubes (60), and the at least two furnace top heat exchange tubes (60) connected in parallel together constitute a furnace top heat exchange tube group (73); The riser heat exchanger group (72) and the furnace top heat exchanger group (73) are connected in parallel.

5. The coke oven top waste heat recovery system according to claim 1, characterized in that: The coke oven includes a carbonization chamber and a combustion chamber, and the furnace top heat exchange tube (60) is arranged in a circuitous manner on the top of the carbonization chamber and the combustion chamber.

6. The coke oven top waste heat recovery system according to any one of claims 1 to 5, characterized in that: The heat exchange medium is demineralized water.

7. The coke oven top waste heat recovery system according to claim 6, characterized in that: It also includes a deaerator (81) and a steam drum (82). The deaerator (81) is connected to a first demineralized water delivery pipeline (91) for delivering demineralized water. The deaerator (81) is connected to the inlet of the steam drum (82) through a second demineralized water delivery pipeline (92). The steam drum (82) is connected to the second medium inlet (601) of the furnace top heat exchange tube (60) and / or the first medium inlet (24) of the riser heat exchanger (1) through a third demineralized water delivery pipeline (93). The second medium outlet (602) of the furnace top heat exchange tube (60) and / or the first medium outlet (25) of the riser heat exchanger (1) are connected to the steam inlet of the steam drum (82); The steam outlet of the steam drum (82) is also connected to a steam output pipeline (97) for transporting steam downstream.

8. The coke oven top waste heat recovery system according to any one of claims 1 to 5, characterized in that: The furnace top heat exchange tube (60) includes an inner tube (62) for conveying the heat exchange medium and an outer tube (61) sleeved outside the inner tube (62). The inner wall of the outer tube (61) has at least one drainage groove opened along its length direction, and a leak detection tube connected to the drainage groove is also connected to the outer tube.

9. The coke oven top waste heat recovery system according to claim 8, characterized in that: There are four drainage channels, which are arranged sequentially at intervals along the circumference of the outer tube. There are also four corresponding leak detection tubes, which are connected to each of the drainage channels.

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