Key points for the installation of coke oven equipment and processes
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Key points of the process installation for coke oven equipment: The main components of the process installation for coke oven equipment include the coke oven heating system, furnace protection fixtures, exhaust gas system, gas collection system, tracks for the four types of vehicles, operation consoles on the machine and coke side, auxiliary equipment for coke ovens, steam pipelines, compressed air pipelines, high and low pressure ammonia pipelines, as well as various other pipeline systems for transporting different media. The furnace protection iron components are one of the main equipment in coke ovens; they are responsible for protecting the bricks that make up the oven body, and they adjust themselves in response to changes in the oven’s temperature, thereby ensuring stable temperatures and the proper operation of the coke oven. Furnace protection components include furnace columns, protective plates, furnace door frames, furnace doors, and vertical and horizontal struts. The installation quality of the furnace protection iron components directly affects the normal operation and service life of the coke oven. The iron components for protecting the furnace are installed after the furnace is built. Based on past installation experiences, it can be concluded that having qualified equipment is a prerequisite, thorough preparation is key, pressurizing the furnace door frame for protection is a challenging task, and safety considerations focus on transportation and lifting. Measures must be taken to protect the equipment during transportation; in particular, the blade edge of the furnace door deforms easily upon contact, which affects sealing. The furnace protection iron components are lifted and adjusted uniformly to eliminate cumulative errors; particular attention is paid to ensuring a seal between these components and the coke oven, as well as to those joints that need to move due to thermal expansion during the furnace heating process. The general installation sequence is as follows: first, install the iron components used to protect the coke oven; then carry out the initial setup of the exhaust gas system, install the operating platforms on the machine and coke sides, and install the oven doors to ensure proper heating of the coke oven. Finally, install and adjust the equipment on the oven roof, the devices for exhaust gas exchange and transmission, the tracks for moving machinery, as well as other auxiliary equipment for the coke oven. Several points to note during construction: 1. Determine the center line of the coke oven; establish the vertical and horizontal center lines in the flue on the machine side of the coke oven, the resistance walls, the furnace bed slab, and the basement as appropriate, and set up triangular markers. 2. Install the elevation reference points; these are usually placed during civil engineering construction, and before installation they are moved to locations that are convenient for construction without interfering with it. 3. All embedded components shall be installed in coordination with civil engineering and furnace construction, to ensure the quality of installation. 4. After cleaning the foundation of the furnace column pedestals, add shims as necessary based on the condition at the bottom of the furnace column to level it to the designed elevation, and initially position the upper and lower cross struts. 5. Lift the properly prepared protective plates into place in groups in sequence, fix them temporarily, and then lift the furnace columns into position; use upper cross straps to temporarily secure the furnace columns and protective plates corresponding to each group on the machine-side and coke-side. 6. After all the furnace column protective plates are temporarily in place, adjust the offset between the center line of each protective plate and the center of the furnace column from within the furnace. Use clamping devices to apply pressure to the protective plates so that the relevant parameters meet the design requirements; finally, fix the upper and lower springs as well as apply pressure to them. 7. The furnace door frame is also hoisted into place in accordance with the factory’s assembly sequence and temporarily fixed with bolts. After adjusting the offset and elevation of the upper and lower center lines, apply pressure for fixation. 8. After the furnace door frame has been adjusted and fixed, initially lift and install the exhaust valve, as well as the connection pipes for the small flue; simultaneously construct the operation platform on the machine side, and try to keep the elevation of the steel beams on the coke side within a negative tolerance, so as to facilitate adjustments to the elevation of the tracks thereon. 9. Fine-tune the exhaust valve once, seal it with asbestos putty, cover the bottom opening of the furnace top rising pipe seat, and complete the equipment installation tasks prior to furnace drying to ensure a successful drying process. 10. The fine tuning of the main track systems, the roof gas collection system, and the exhaust gas system is all carried out during the furnace heating period. 11. After fine-tuning the exhaust gas valve, connect the exchange transmission device that has passed the trial run. Without affecting the oven operation, debug the exhaust gas system as soon as possible (mainly focusing on the exchange transmission device, the hydraulic station, and the pipelines); address any issues promptly to ensure the coke oven can be put into use at the earliest possible time. 12. The exhaust gas collection pipes can be joined section by section on the ground inside the shelter before being lifted into place, or they can also be lifted section by section onto supports and welded together at a higher height – the choice depends on the conditions on site. 13. During the alignment of the gas collection pipes, strict control is exercised over the spacing between flanges and the perpendicularity of the flange surfaces to prevent welding deformation. 14. Except for those tracks that require construction in the hot state, all major track installations can be completed during the cold state, with preparations made for the hot-state installation of tracks in the coke oven area. The key aspect of construction for coke oven pipelines is ensuring proper sealing; qualified raw materials and equipment must be used, and strict welding techniques are required to guarantee welding quality. Its blast furnace gas, coke oven gas, and high- and low-pressure ammonia water are all toxic and harmful gases; the construction techniques and quality determine whether the safe and normal operation of the coke oven can proceed smoothly. Welding of pipelines is a key aspect; we employ the construction methods and inspection procedures of \"decontamination and descaling, proper preparation of the groove, thorough cleaning at each layer, and use of penetration photos\". Before pipeline construction, when technicians familiarize themselves with the drawings, especially for the fabrication of coiled heating gas pipes in basements, it is necessary to follow the site conditions and the construction drawings. Prepare the layout diagram and number it properly. For special processes and critical areas (such as the welding of hydraulic pipes in hydraulic switches, the positioning of pipe connections at hot states, the interfaces of gas pipes in underground heating systems, and the interfaces of high-pressure ammonia water pipes), technicians prepare process cards to ensure traceability of construction quality. Attention must be paid to the protection of the finished products; in particular, when handling cast iron components such as valves and orifice plate boxes during transportation, loading, unloading, and construction, they should be handled with care to avoid damage. When processing non-standard components such as water seal grooves, venting and ignition devices, and non-standard butterfly valves, it is essential to follow the design and construction specifications strictly. During pipeline construction, pay attention to the quality of the welding grooves and welds; the pipes of the hydraulic switch should be pickled and degreased, and argon-electric welding should be used for its joints. Attention must be paid to the protection of the finished products; in particular, when handling cast iron components such as valves and orifice plate boxes during transportation, loading/unloading, and construction, they should be handled with care to avoid damage. When processing non-standard components (such as water seal grooves, venting and ignition devices, non-standard butterfly valves, etc.), it is necessary to follow the design and construction specifications strictly. Several issues to note during construction: 1. For the construction of pipelines in the coke oven heating gas system, large-diameter steel pipes (DN≥400) are rolled into shape; when processing and aligning these rolled pipes, attention must be paid to the quality of the welds (double-sided welding is generally required for DN≥600), as well as the amount of misalignment and ellipticity of the pipe walls. These deviations must comply with the pipeline construction standards and design requirements. 2. Before leaving the factory, the coiled tube should undergo a coal penetration test in accordance with the design requirements. 3. Before pressuring the heating gas system, all instrument connections must be completed so that the instruments and the piping system can be pressurized together. 4. The control valves, orifice plate boxes, lower spraying devices, and other components of the gas heating system beneath the furnace must be installed in accordance with the installation specifications for coke ovens, to ensure that their vertical, horizontal, and elevation deviations are within the required limits. 5. For the flange connections of the gas heating system pipes, especially for flanges with a diameter of DN≥400, φ10 oil-impregnated asbestos packing is used as the sealing material; for the remaining flange connections, asbestos-rubber sheets (with a thickness of δ=3mm or δ=5mm) are employed. 6. The pipes on the machine side of the furnace roof should be installed after the gas collection platform is largely completed, but care must be taken to reserve spaces for hot-state connections (such as water supply pipes for production, connections to the balance tank, steam pipes, compressed air pipes, etc.). 7. The elbows in the ammonia-water pipes on the machine side of the furnace roof are fabricated using a hydraulic pipe bending machine and prepared in advance before installation. In particular, the welding quality of DN25 seamless steel pipes and the quality of pipe fittings must meet the requirements specified in the design and construction standards. For the tee ball valves and connecting pipes that lead into the rising pipe, a method that combines design considerations with on-site implementation should be used for pipeline installation; it is important to ensure that the rows of pipes appear neat and aesthetically pleasing, and brackets at the tee ball valve locations should all be at the same elevation. When connecting the suction elbow to the external raw coal gas pipeline, installation can be carried out in a cold state, but dimensions suitable for hot-state connection must still be taken into account. 9. During the installation of all pipes, it is necessary to keep the inside of the pipes clean, especially for large-diameter pipes with a DN of ≥600. Manual cleaning by entering the pipe is used; when working on small-diameter systems (especially ammonia systems with DN25), care should be taken to prevent impurities from entering the pipe. 10. Before completion of construction and pipe painting, conduct pressure testing and flushing tests on the pipes. It requires compliance with the design drawings as well as construction standards and regulations; however, for the ammonia pipeline system, pressure is applied from the direction of the ammonia pump room. Proper drainage measures must be taken before flushing the pipes, especially to ensure that the wastewater does not flow onto the refractory material on the top of the furnace. 11. The pipe connections in the basement water seal groove must not be mistaken. (Pipes such as water pipes, steam pipes, and condensate discharge pipes) 12. The condensate discharge pipes must be installed with a slope that complies strictly with the design requirements. 13. Before the pipeline system is put into use, it is necessary to perform a pre-flushing with the medium. (The gas pipelines are purged with compressed air; when the coke oven switches to internal heating, the flange connections at the bottom of the switching valves should be inspected again in conjunction with the production team, and it is important to have a sufficient number of CO detectors available. The coke oven must undergo a gradual heating process from a cold state to full production. After the coke oven is heated up, it expands, and some of the oven structures and equipment cannot be sealed or fixed at that time. Installation and fixation are carried out once the expansion of the oven has largely ceased. Most of these tasks need to be completed after the maximum degree of expansion has occurred (at 550°C), before operations begin. This process takes a short amount of time, but involves many different tasks; moreover, it has a significant impact on the quality of the coke oven. Therefore, special attention must be paid to ensuring quality control, proper planning, and the establishment of measures to guarantee quality. The main construction tasks include: 1. Sealing the base of the rising pipe with mortar containing asbestos rope at temperatures above 600°C. 2. Adjusting the positions of the socket joints between the bridge pipe and the rising pipe, inserting asbestos rope, and testing whether the flap operates smoothly at temperatures above 650°C. 3. Connecting joints such as those for the air intake pipe and tar box at temperatures above 650°C. 4. Installing and adjusting the tracks for the smoke removal and dust suppression vehicle; installation can be carried out slightly earlier than this temperature. 5. Installing and adjusting the wiring racks and conduits for the smoke removal and dust suppression vehicle at temperatures above 650°C. 6. Adjusting the work platforms on both sides and removing the temporary struts; this is done after reaching 650°C. For furnace columns with significant verticality deviations, these are adjusted, the fixing screws are tightened, and then the temporary struts are removed. 7. Cutting away the set screws used to hold the protective plate over the top of the furnace door on the furnace column, after reaching 650°C. 8. Welding and fixing the safety railings on the furnace top, after reaching 650°C. 9. Removing the longitudinal strut adjusters, after reaching 750°C. 10. Connecting the tracks of the smoke removal and dust suppression vehicle to the end platforms, after reaching 700°C; concrete for the work platform in that area is then filled in after the connection is made. 11. Adjusting the tracks of the coke blocking vehicle and connecting them to the control panels at both ends, after reaching 700°C; concrete for the work platform in that area is filled in after the connection is made. 12. Removing the temporary walkways used for measuring the furnace during drying, after reaching 800°C. 13. Removing the coal gas pipelines used for furnace heating, around 800°C. 14. Conducting a test run of the transmission system at 650°C. 15. Finalizing the connections of the branch pipes for the coal gas pipelines in the basement, at 600°C℃
Installation of embedded components: I. The installation of flue bends shall comply with the following requirements: The tolerance for the distance between the longitudinal centerline of the flue bend on the machine-coke side and the front line of the coke oven is ≤ 5 mm. The tolerance between the transverse centerline of the flue elbow outlet and the centerline of the regenerator wall is ≤ 5 mm. The elevation tolerance for the flange of the flue elbow is ≤ -5 mm. The outlet of the flue elbow must be horizontal. Its allowable deviation is 1% D (diameter of the pipe opening). II. Installation requirements for components embedded in the furnace roof: Embedding of coal loading holes: These can be installed once the furnace body has been brick-lined. Before burial, check whether the contact between the coal loading hole seat and the coal loading hole cover is smooth. During installation, first clean the bottom surface of the coal-loading hole seat. Apply clay mortar to the outer surface of the seat, wrap it with loose asbestos rope (Φ2–3mm), apply another layer of mortar over the asbestos rope, and then construct the coal-loading hole seat. After installation, the coal loading hole seats must be level; the centerline of all coal loading holes in the furnace should lie on the same line as the designed centerline, with a tolerance of ±5 mm. The coal loading hole seats shall not be higher than the surrounding brick surface, and the gaps around them must be sealed properly. For those located on the end walls, the coal loading hole seats should be installed according to actual needs after furnace drying. Installation of the fire viewing hole seat: It is basically the same as the method used for installing the coal loading hole seats. The fire viewing hole seat must fit tightly against the cover, and care must be taken during installation to prevent mortar from falling into the combustion chamber. The fire viewing hole seats located on the end walls should be installed according to actual needs before furnace heating. After installation, the fire viewing hole shall not be lower than the furnace top surface; it should be 0–3 mm higher than the furnace top surface. Installation of temperature measurement holes in the regenerator: Before installation, it is necessary to check the tightness between the seat and cover of the temperature measurement hole in the regenerator, using a 0.05 mm feeler gauge for inspection. During installation, wrap asbestos rope coated with clay mortar around the base, then apply clay mortar slurry and insert it into the pre-made hole; finally, seal the outside properly. The temperature measurement hole base should be coated with butter to prevent rust. Installation of coke oven equipment I. Protective plates: Original records should be kept of the dimensions of the oven frame and protective plates during individual inspections, and they should be fitted together and numbered according to the tolerance levels. Small iron wires are welded into the recesses on the inside of the protective plate, and then fire-resistant mortar is applied (composition: 20% 400# silicate cement, 80% crushed diatomite bricks). The surface of the mortar should be 5 mm lower than the surface of the rebar, and a curing time of over 24 hours is required when the temperature is above 5°C. The protective plate should be pre-installed before actual installation, in order to check the tolerance fit of the protective plate and the furnace frame, verify that all connection dimensions are correct, and test and assess the specifications of the asbestos rope used. For each combustion chamber, the furnace column protection plates and corresponding furnace frames are installed simultaneously on both sides of the machine frame; temporary installation tools must be used to tighten them (see the attached diagram). It is not allowed to apply pressure using furnace column set screws or to tighten them directly with furnace column struts. The front surfaces of two adjacent protective plates must be level with each other (on the plane that is in contact with the furnace frame), within a tolerance of 2 mm. Due to the requirements of mechanical cleaning, the tolerance for the distance between the front surface of the protective plate and the front line of the coke oven at the upper, middle, and lower positions is –0 + 5 mm. The surface where the grinding plate is placed between the two protective plates must be level, with a tolerance of 2 mm. The gap between the lower edge of the protective plate and the furnace brick base should be within the range of 5–7 mm. An asbestos pad should be placed between the lower edge of the protective plate and the surface of the base tile. The gap between the furnace shoulder and the protective plate should be 3–10 mm; in cases where individual bricks are sunken, the gap may be up to 13 mm. In areas where the bricks at the furnace front are sunken, asbestos tape must be used as an additional filler when adjusting the protective plate. The asbestos tape must be placed on the inside of the asbestos rope, and the asbestos ropes must be pressed tightly in place. It is absolutely not allowed for the protective plate to make contact with the iron bricks. The center of the protective plate must align with the reference center line of the combustion chamber (not the actual construction center line of the combustion chamber), with a tolerance of ±3 mm. The protective plate shall not protrude into the walls of the carbonization chamber, special attention being paid to the coke side to avoid interfering with coke pushing. The gap between two adjacent protective plates must be kept greater than 5 mm, and sealed with asbestos rope. The joints of the asbestos rope pressed on the back of the protective plates are prohibited from being located at the joints of two adjacent protective plates. After installation, fill the gap between the protective plate and the upper part of the furnace head with waste paper to prevent dirt and debris from falling in and affecting the quality of pouring. Pour material into the gap between the protective plate (or furnace frame) and the furnace head once the furnace temperature reaches 700–750°C. The thermal loss on ignition of asbestos rope should not exceed 32%. II. Furnace Columns: When transporting, storing, or lifting furnace columns, special care must be taken to avoid increasing their degree of bending. The allowable tolerance for the furnace column elevation is ±10 mm; the console brackets can be installed at the time of console setup. The center of the furnace column should be aligned with the center line of the protective plate. Tolerance ±3mm. Any debris or burrs between the furnace column and the protective plate should be cleaned away. The groove for the pull strip should be cleaned thoroughly before installing it. Along the entire length of the brick trench, wooden strips are placed every 2–2.5 meters. The thickness of the wooden block should be such that the distance between the bottom of the brick trench and the surface of the tie bars is roughly equal to the upward expansion amount of the coke oven during baking (130–140 mm). Apply butter to the slip plate of the anchor bolt holes at the lower part of the furnace column. Springs should be numbered in groups: each set of springs should fall within the same tolerance range; generally, those with a tolerance of ±1 mm within their operating pressure range are grouped together, and springs with similar heights and pressures are placed side by side for easier management. When installing the springs, it is necessary to check them against the corresponding specifications and apply pressure according to the required tonnage; first apply pressure to the larger springs, and then to the smaller ones. For ease of installation, the regenerator guard plate is sometimes spot-welded to the furnace column; before the spring mechanism applies pressure, these spot welds must be disconnected. After the spring is applied, the bending degree of the furnace column should not exceed 15 mm, and detailed records should be kept. Spring pressure gauge before furnace drying: Taking a carbonization chamber height of 4.3m as an example, the large spring at the upper part of the furnace column weighs 5–6 tons; the large spring at the lower part of the furnace column also weighs 5–6 tons. The spring on the large protective plate (small) has a weight of 1.5–2 tons, while the spring under the large protective plate (small) weighs 2–3 tons. The spring on the regenerative chamber’s protective plate weighs 1–1.5 tons. The spring on the smaller furnace column weighs 0.8–1 ton. ×: For each tie rod, the force applied by the spring should be 2.5–3 tons. The crossbars installed on the furnace column and the thrust bolts must be secure; the distance between the crossbar and the top surface of the protective plate should be 90–95 mm. The bolts used for compression should be tightened such that there is still a distance of 10–15 mm from the edge of the protective plate, allowing for adjustments during the furnace drying process. III. Furnace frame: The furnace frame should be installed after the furnace columns are pressurized. When installing the furnace frame, care must be taken to align it with the center line of the carbonization chamber. It is essential to ensure that the inner edge of the furnace frame does not protrude beyond the protective plate; this should be checked carefully, especially after tightening the screws. To this end, temporary supports should be added to the furnace frame during installation to prevent deformation due to differences in width. Once the position of the furnace frame is fixed, the bolts must be tightened from the center in an upward and downward direction; moreover, the bolts on the left and right sides should be tightened crosswise to ensure even stress distribution across the furnace frame and prevent deformation. When tightening the furnace frame bolts, special care must be taken to ensure that the asbestos rope is placed in the designated groove. After tightening, the gap A between the furnace frame and the protective plate should be less than 3 mm; it cannot be zero. Since the pressure-applying surface is on the inside, it is not possible to measure it from the outside. Illustration: The B value of the furnace frame should be measured and recorded according to the frame’s identification number. Once the furnace frame is installed, the C value is measured, and then the A value can be determined. After the grinding plate is fixed, its surface should be 7–10 mm below the bottom surface of the carbonization chamber; if it does not meet this requirement, the grinding plate can be planed thinner. IV. Control Panel: The tolerance for the elevation of the control panel pillars is 0–5 mm. The tolerance for the elevation of the operating console on the Anxious side (the elevation of the steel frame surface) is ±3 mm, with measurements taken every 10 meters. Yellow glycerin should be applied to the sliding surface of the console, and care should be taken to keep it clean. The control panels located on the front of the coke ovens on both sides of the machine, as well as those situated between the oven ends, should all be disconnected. A space of about 1 meter should be left on that side without pouring concrete there; concrete pouring should be carried out only after the oven temperature reaches 650°C. The tracks for the coke handling vehicles should also leave room for the expansion of the oven structure (usually 85–105 mm). V. Exhaust tray: Before installation, the equipment should be inspected after the exhaust tray is delivered to the site. First, check the shape of the exhaust manifold and verify its dimensions, paying special attention to the dimensions of the connection pipes as well as any signs of damage that may have occurred during handling. Check the tightness of the air cover: Insert a 0.05mm feeler gauge between the covers; if it cannot be inserted, it is considered satisfactory. Check the tightness of the exhaust tray, exhaust gasket, and gas gasket: The test for the exhaust tray involves filling the tray with water to a depth of 40 mm; no leakage indicates success. Test for gas thallium: At the gas inlet flange, connect a 0.03 cubic meter air tank and conduct a test with compressed air. Its pressure is 450 mm of water column; after five minutes, the drop shall not exceed 150 mm. (Since the required pressure is low, a pump can be used as a source of air for pressure testing instead of a compressor.) Those who fail the test should be ground until they pass. During testing, the thallium discs are lowered by rotating the driving pull rod; it is not possible to test the thallium discs individually on their pedestals. (IV) The exhaust flue must be installed in advance to identify any defects in the furnace’s brickwork and the construction of the flue. (Elevation, center distance errors, and expansion joints after installation) 8 units should be installed at each corner and in the middle of each coke oven. The transverse center line of the exhaust gas tray (the center of the suspension rod or the handle) should be aligned with the center line of the small flue (or the center of a single wall in the regenerator), so as to ensure that the gaps between the edges of the connection pipes and the lining brick walls on both sides of the small flue are uniform and greater than 5 mm. The longitudinal center line of the waste gas tray shall lie on a straight line parallel to the front line of the coke oven, with a tolerance of ±3 mm. If the exhaust flange connection pipe is designed with a flange, care should be taken to ensure that the distance between the flange surface and the lining bricks of the small flue is not less than the specified requirement. The required tolerance for the elevation at the top of the exhaust flange is ±2 mm; it is necessary to ensure that there is a gap of more than 5 mm between the bottom surface of the connection pipe (or the bottom surface of the flange) and the bottom tiles of the small chimney. The exhaust gas tray must be installed level. The levelness tolerance is 1/1000. The gasket plate at the lower part of the exhaust stack should not protrude between the bends of the flue. After the exhaust gas tray has been properly installed and adjusted, the gap between the small flue opening and the connecting pipe should be sealed with asbestos rope; it should not be tightened too much, so as not to prevent the furnace body from expanding freely. Once the furnace temperature reaches 600°C and the exhaust gas tray is finally adjusted properly, that joint, as well as the joint where the flue bend meets the exhaust gas tube, should be tightly sealed with asbestos rope and then covered with mortar. After the installation and adjustment are complete, a thallium lift test must be carried out to ensure that the thallium rod does not get stuck. During this test, the flap located below the exhaust gas tray must rotate smoothly; it should be able to open or close completely when the pointer on the scale outside the exhaust gas tube indicates the extreme position. VI. Transmission exchange: There should be no noticeable gaps on the left and right sides between the exchange plug and the plug’s square end, to prevent interference with the accuracy of the exchange movement. The slider on the pull strip should slide smoothly within the long slot on the handle, with no signs of jamming or wear. The tie rods and sprockets should rotate smoothly, and the sprocket brackets should be welded firmly. The centers of the grooves on the outer edge of the pulleys that support the exhaust straps should lie on a straight line, with a tolerance of ±3 mm. The elevation of the centers of the pulleys should be consistent, with a tolerance of ±5 mm (in the case of exhaust trays with handles, the axis of the handle should be used as the reference). The travel distance of the drive tie rod should meet the design requirements. The markings on the valves must be checked to ensure that they are fully open in the fully open position, with a permissible deviation of 1 mm. For coke oven gas valves, the permissible deviation is 2 mm in the fully closed position, while for blast furnace gas valves, it is 5 mm. (Note) To adjust the stroke of the drive tie rod, several repeated drive adjustment tests must be carried out until no change is observed. The total travel of the exchange pull rod can meet the design requirements through the travel at one end of the exchanger during the transmission process; however, the other end cannot achieve these requirements due to the loose condition of the steel wire rope. Therefore, the travel at the fixed end is adjusted to meet the design requirements, while the allowable travel at the loose end can be 20 mm less than the design value. The switch is designed to be operated by hand in order to adjust the height of the exhaust tailpipe, as well as the height of the exhaust tailpipe and the air cover; these heights must comply with the required tolerance of ±5 mm. First, check each one individually; only after ensuring there is no tightness can the trial operation of the transmission be carried out. During the switching process, there should be no strain on the sprocket or the exhaust tailpipe, and the movement must be vertical. The exchange drive should be adjusted before switching to normal heating, and it needs to be adjusted again after switching to normal heating. VII. Trial operation of the switch and switching drive: After the cylinders are installed, the degree of misalignment between their centerlines and the centerlines of the rim wheels of the coke oven must not exceed 3 mm, and the travel range at both ends of the cylinders must be symmetrical with respect to their center.