Seeking help: Plan for the sulfur burning furnace and boiler curing furnace in a sulfur-based acid production plant

This is a startup plan for sulfur-based acid production for reference. Startup Plan for Sulfur-Based Acid Production Facility 1. Overview Before feeding material into the acid system or igniting the facility (including heating it up), it is necessary to ensure that the supply of all utility services is operating properly. 1. Inspect the cooling water system, including the demineralized water system, to ensure normal water circulation. 2. Inspect the water treatment system to ensure that treated water is available at any time. 3. Check the device’s air and instrument air systems to ensure they are operational. 4. During the first start-up of the unit, the steam pipeline should be purged with steam. II. Boiler feedwater system 1. For deaerator cleaning, the water should not pass through the boiler feedwater preheater; instead, it should be routed via a bypass to fill the deaerator for cleaning. 2. As the deaerator level rises, check whether the level alarm and level control system are reliable and can operate properly. Also, flush the pipelines of the usual boiler feed water pump and install a start-up filter. 3. Heat the deaerator with low-pressure steam, increase the pressure, and check the steam regulation. 4. Open the drain, bypass, and vent valves of the economizer. Open the steam drum vent valve and emergency blowdown valve. Close the saturation steam outlet isolation valve and check valve of the drum, and open the level control valve as well as the blowdown and regular drain outlet isolation valves. 5. Start the feed water pump, with the outlet valve slightly open. Flush the pipeline up to the economizer section. Once all the air has been expelled, close the vent valve. After the pipeline is clean and free of rust or debris, close the drain valve (that is part of the equipment itself), and use the manual bypass for boiler level control to regulate the flow rate. 6. Continue to feed water until the water discharged through the continuous and regular drainage of the boiler is clean at normal pressure. Close the drain valve, and stop feedwater supply when the drum liquid level is at the normal operating level. 7. Test the boiler water quality and prepare the chemicals for addition. 8. Drain the bypass for shutdown due to low water level in the drum, so that the boiler’s liquid level control switches to automatic mode, and set the normal operating liquid level adjustment parameters. Set the liquid-water adjustment of the ejector to automatic mode. III. Commissioning of the acid system 1. Preparation work Before introducing acid into the acid system, it is essential to complete all of the following operations: 1.1. All towers, tanks, exchangers, and pipelines must be cleaned of any debris. 1.2 The pipeline has undergone a hydrostatic test as required during construction. Remove all blind flanges and drain the water from the system. 1.3 Check the operation of all drain valves. Drain the water from the container. 1.4. Inspect all pipelines and valves in the acid inlet systems. 1.5 All instruments are in operational status. The valves for the acid concentration analyzer inlet should be closed. 1.6. Sufficient supply of 98% concentrated sulfuric acid must be available while driving. The entire system may need to have its acid replaced as many as three times. More acid may be needed, depending on the amount of moisture absorbed from the air during the heating up of the converter. 2. Safety work 2.1. Check that all safety flushing facilities in the acid area are operating properly. 2.2 Isolate the acid area with ropes. All non-direct personnel are not allowed in. 2.3 Wear the necessary personal protective equipment. 2.4 Prepare a hose to rinse any leakage points with water. 2.5 Be prepared to use lime or soda ash at any time to neutralize acid spills, and clean them up promptly. 3. Acid addition: Before heating the acid unit, the acid system should be filled with acid from the finished acid tank, and circulation should be started. When the system starts acid filling, it fills one device at a time through the acid drainage system. This reduces the number and locations of potential leakage points that must be addressed within a certain period of time. The following are reliable and safe methods for systemic acid infusion. 3.1 At the circulation pump tank, the dilution water flow control valve must be closed. The automatic and manual isolation valves should be closed. The discharge valve opens. 3.2 Open the drain valve on the water pipe side of the acid cooler. The level control valve and the outlet isolation valve of the acid circulation pump tank must be closed. The isolation valve at the outlet of the acid drainage pump must be closed. 3.3 The conductivity meter at the drain of the boiler feedwater preheater should be functioning properly. The boiler preheater should be filled with water. 3.4 Begin feeding acid into the mixing pump tank through the acid storage tank outlet pipeline. Check the pipelines and pump tanks for leaks. 3.5 Check the operation of the acid discharge pump before the pump tank is completely filled.  Stop feeding acid from the acid storage tank when the liquid level in the pump tank reaches 500 mm. Adjust the valve near the acid discharge pump so that it sends the acid coming from the pump tank back to the pump tank.   Open the acid drainage valve of the pump tank and start the acid drainage pump.  After checking the acid discharge pump and the acid discharge pipeline, stop the acid discharge pump. Turn off the acid discharge pump and the valves in the pipelines leading to the pump tank. 3.6 Adjust the valve again and continue to pour acid into the acid circulation pump tank.  Open the drainage points of the sealing circuits for Tower 1 and Tower 2, as well as the drainage points at the following locations: main acid cooler, finished acid cooler, boiler feedwater preheater, and acid circulation pump tank.  Restart the acid in the finished product tank and transfer it to the 98% acid circulation pump tank.  As the pump tank fills up, use a steel rod to check the liquid level indication in the pump tank. When the furrow irrigation level reaches approximately 2750 mm, stop feeding acid from the acid storage tank.  Shut off the drainage points of the sealing circuits for Tower 1 and Tower 2, as well as the drainage points at the following locations: main acid cooler, finished acid cooler, boiler feedwater preheater, and acid circulation pump tank. At this point, the liquid level in the acid circulation pump tank is sufficient to supply acid to the acid cooler and most of the sealing circuits in the gas return lines. 3.7 Send several people dressed in protective gear to conduct a thorough inspection, checking for any leaks at key locations in the acid system. 3.8 Adjust the valves on the circulation pipeline, and start the acid circulation pumps for the drying tower as well as the first and second absorption towers.  Adjust the flow controller of the drying tower to maintain it at ~m3/h. Set the controller to manual mode and 75% activation. Set the acid temperature controller of the drying tower to 66°C, and also set it to the manual mode with 100% activation.  Adjust the flow regulator of one absorption tower to ~m3/h. Set it to manual mode with 25% activation. Adjust the acid temperature regulator of the absorption tower to 82°C. Set it to manual mode and turn it on at 100%.  Adjust the flow regulator of the second absorption tower to ~m3/h. . Set it to manual mode with 25% activation.  Adjust the boiler feedwater preheater temperature regulator to the manual position. Close the temperature control valve and the inlet acid valve. Adjust the manual valve at the outlet of the common cooler to 25% open.   Set the acid cycle pump tank level regulator to manual mode and close the level control valve. On-site check the positions of all acid flow, temperature, and level control valves.   Start the acid circulation pump with the pump outlet closed. Gradually open the outlet valve to 25%–50%. In this way, the sudden surge in motor current and the impact on the piping system and cooler can be reduced when the pump starts up. After the pump starts operating and the liquid level in the pump tank stabilizes, gradually open the outlet valve to 100%. It may be necessary to open the flow control valve of the absorption tower to 50% in order to ensure sufficient acid flows back to the pump tank.  Check for leaks in the acid inlet and reflux lines of the drying tower.  Set the flow regulator of the drying tower to automatic mode and adjust it to ~m3/h. Close the level control valve. Check for leaks in the acid inlet and reflux lines of the drying tower.  Gradually adjust the flow regulator of one absorption tower to bring the flow rate to approximately ~m3/h. Then set the regulator to the automatic position. Check for leaks in the acid inlet and reflux lines of the absorption tower.  Gradually adjust the flow regulator of the second absorption tower to bring the flow rate to approximately ~m3/h. Then set the regulator to the automatic position. Check for leaks in the acid inlet and reflux lines of the second absorption tower.  During the acid circulation process, check the liquid level in the acid circulation pump tank. If the liquid level is below 1,100 mm, more acid should be supplied from the finished product tank.  Set the acid and temperature regulators of the drying tower and absorption tower to the manual position repeatedly. Open the cooler outlet manual valve to 100%, and close the utility acid cooler bypass valve. Check whether the acid flow to each tower meets the design values.  Open the temperature valve to allow the acid to flow through the preheater. Check whether the acid flow to each tower meets the design values. Put the temperature regulator back in the automatic position.  During the acid cycle, monitor the conductivity meter in the boiler feedwater pipeline. An increase in conductivity indicates an acid leak in the boiler feedwater preheater. Stop the machine, drain the acid system, and repair the leak.  Open the inlet and outlet isolation valves of the finished product cooler. Open the isolation valve on the acid drainage line of the deacidification circulation pump tank. Close the manual isolation valve on the finished acid outlet pipeline. The valve should be adjusted to allow circulation between the finished acid cooler and the pump tank.  Gradually open the pump tank level control valve. Check the finished acid pipeline for leaks.   Measure the liquid level in the acid circulation pump tank, and record any drops in level for future reference. The liquid level must be above ~mm. This is the lowest operating liquid level in the acid cycle pump tank.  Check the drainage points of the utility and finished acid coolers for acid leaks. Close the water-side discharge valve, and open the inlet and outlet valves for the cooling water of the cooler.  Turn on the conductivity meter on the cooling water return pipe. Start the cooling water circulation. Do not run the cooling water fan.  Check the conductivity of the cooling tower water and boiler feed water, and compare it with the readings from the conductivity meter. Send the sampled acid to the laboratory. If the acid concentration is below 93%, adjustments should be made.   Continue the acid cycle in all three towers for about 24 hours. After checking for leaks in the pipelines and coolers, the acid circulation via the finished product cooler can be stopped. 4. Inspection work 4.1 During the acid circulation process, open the manholes at the elevation of the acid separation units in the drying tower, the first absorption tower, and the second absorption tower, and observe the flow conditions in the acid separation tank. Permanently close the manholes of Tower 1 and Tower 2. Close the dryer manhole, but do not tighten the bolts completely. Because it needs to be opened again when the device is heated. 4.2 Pass the acid through the acid concentration conductivity meter. Samples of the acid are taken in the pump tank and sent to the laboratory. Compare the laboratory analysis results with the readings of the conductivity meter. 4.3 After approximately 24 hours, measure the liquid level in the acid circulation pump tank, and then turn off the acid circulation pump. When the liquid level in the pump tank stops rising due to the discharge from the tower, measure the liquid level and record the discharge volume for future reference. 4.4 Open the manhole on the bottom shell of the absorption tower. (Due to the height of the seal tube of the acid outlet pipeline, there will be acid at the bottom of the tower.) ) Adjust the acid discharge pump pipeline to direct the acid from the sealing tube to the acid circulation pump tank, thereby removing the acid at the bottom of the tower. 4.5 Remove the debris remaining at the bottom of the tower and in the acid outlet filter. 4.6 Permanently close the bottom of one absorption tower. 4.7 For the drying tower and the double absorption tower, repeat the operations in steps 4.4–4.6. 5. Refill the acid system with acid for circulation. 5.1. Open the drain for acid from the acid circulation pump tank, and adjust the amount of acid sent back to the pump tank as well as the amount of acid drained through the sealing tube. Fill the pump tank to the lowest starting liquid level, or ~mm, with the higher level taking precedence. Close the acid discharge valve. 5.2 Close the outlet valve of the acid circulation pump to 25% open, then start the pump. Gradually open the outlet valve after the pump starts running. 5.3 Check that the acid flow rates to the drying, first absorption, and second absorption towers are in line with the design values. 5.4 All tower manholes (except those at the elevation of the acid separator in the drying tower), including the demister and the manhole at the top of the tower, must be permanently closed. 5.5 Put all the instrument loops in the acid circulation system into operation. Close the manual isolation valve and open the manual drain valve at the inlet of the dilution water flow control valve. 5.6 Check the pH value of the cooling water and compare it with the reading from the conductivity meter. 5.7 Take acid samples from the pump tank and send them to the laboratory for analysis. Check the acid concentration and compare it with the indication of the acid concentration regulator. 5.8 Stop the water circulation in the cooling tower, and simultaneously shut down the acid circulation pump. IV. Commissioning of the nicotinic acid system 1. Preparation work: At the beginning, the nicotinic acid system is filled with concentrated acid to check for any leaks in the system, while circulation is carried out through the equipment. Before introducing acid into the system, it is essential to ensure that the following tasks have been completed: 1.1 All towers, tanks, exchangers, and pipelines are clean and free of debris. 1.2 The pipeline has undergone a hydrostatic test as required during construction. Remove all blind flanges and drain the water from the system. 1.3 Check the operation of all drain valves. Drain the water from the container. 1.4 Check all pipelines and position valves in the acid inlet systems. 1.5 All instruments are in operational status. The valves for the imported nicotinic acid concentration analyzer should be closed. 1.6. Sufficient supply of 98% concentrated sulfuric acid must be available while driving. The entire system may need to have its acid replaced as many as three times. More acid may be needed, depending on how much moisture is absorbed from the air during the heating of the converter. 2. Safety 2.1. Check whether all safety flushing facilities in the area are operating properly. 2.2 Isolate the area with ropes. All non-essential personnel are prohibited from entering. 2.3 Wear the necessary protective clothing. 2.4 Prepare a hose to rinse any leakage points with water. 2.5 Be prepared to use water-diluted stone powder or soda ash at any time to neutralize acid leaks and spills. 3. Acid introduction: Before conducting the acid system circulation test, acid is introduced into the nicotinic acid system to establish circulation. At the beginning of acid filling in the system, one device is filled at a time through the acid drainage system. This is the number and location of potential leakage points that must be addressed within a certain period of time. The following are the reliable and safe procedures for systemic acid infusion. 3.1 Open the water-side drain valve of the nicotinic acid tower cooler. Confirm that the liquid level control valve for the nicotinic acid circulation pump tank is closed. The isolation valve at the discharge port of the acid drainage pump and the discharge valve of the nicotinic acid pump tank must be closed. 3.2 The conductivity meter on the desalinated water circuit must be operating properly. The desalinated water system should be filled with water and ready for circulation. 3.3 Ensure dry air purging is provided on the nicotinic acid pump. 3.4 Manually open the control valve to start pumping acid into the nicotinic acid tower’s pump tank through the acid lateral flow pipeline. Check the pipelines and pump tanks for leaks. Another method is to feed the acid from the acid storage tank into the nicotinic acid tower pump tank. 3.5 Before the pump tank is completely filled, check the operation of the acid discharge pipeline.  When the liquid level in the pump tank is 500 mm, stop feeding acid from the acid circulation pump tank. Adjust the valve near the acid discharge pump so that it sends the acid coming from the nicotinic acid tower’s pump tank back to that same tank.   Open the acid drainage valve of the pump tank and start the acid drainage pump.  After checking the acid discharge pump and the acid discharge pipeline, stop the acid discharge pump. Turn off the acid discharge pump and the valves in the pipelines leading to the pump tank. 3.7 Send a few people dressed in protective gear to check for leaks at key locations in the acid system.  Set the flow regulator of the drying tower to automatic mode and adjust it to ~m3/h. Close the level control valve. Check for leaks in the acid inlet and reflux lines of the drying tower.  Start the desalinated water circulation. Turn on the conductivity meter on the demineralized water system. Check the conductivity of the deionized water and compare it with the reading from the conductivity meter.  V. Heating the unit: Before heating the unit, all steam pipelines must be purged using the startup steam available in the unit. Once all the aforementioned tasks are completed, the device can be heated. Heating is carried out in four steps: 1. Refractory brick curing – furnace drying, 2. Dry blowing, 3. Direct flue gas flame, 4. Sulfur flame. During the first startup, stage 1 takes much longer than the subsequent startup steps. This is because the curing process for newly laid refractory bricks is slow, and the boiler must be fired up. Between the various heating stages, blind flanges, valves, and vent points must be rearranged. Refer to the attached table for the positions of the valves at various driving stages. All insulation work must be completed before the equipment is heated. Insulation for boilers, converters, steam jackets, and electric heat tracing pipelines must be completed. All steam pipelines and traps shall be purged and tested. VI. Operation of the boiler system during heating: Keep the steam temperature regulator of the superheater at 450°C. Set the regulator to the manual position and open the bypass temperature valve. Control the superheater steam temperature regulator at 435°C. Set the regulator to the manual position and open the bypass temperature valve. Adjust the pressure regulator of the high-pressure steam main to 38.2 Mpa. The steam generated at the beginning of the heating process must be vented. The waste heat boiler level regulator must be in operation and adjusted to the normal operating range. Confirm that the low-low liquid level interlock of the boiler is in operation. During the curing, heating, and soaking processes of refractory bricks, the boiler’s check valves and isolation valves should be closed, while the vent valves should be opened. When the boiler pressure rises to about 1.75 Mpa and a strong stream of steam can be seen at the vent point, close the vent valve. Boil the boiler in accordance with the boiler manufacturer’s and/or user’s water treatment instructions. After boiler cooking, flushing, and inspection are completed, water is added to the boiler again. Raise the boiler pressure to approximately 1.75 Mpa, close the vent valve, and open the outlet isolation valve and check valve. Keep heating up. VII. Preheating of the sulfur incineration furnace/ curing of refractory bricks 1. Install a starting fuel nozzle at the flange where the sulfur incineration furnace is mounted. 2. Remove the plug from the drainage point at the bottom of the sulfur incinerator shell. 3. Determine the positions of the valves, vent valves, and blind flanges according to the details listed below and Table 17-1. For the locations of the blind flanges and valves, see Figure 17-1. 4. Bypass interlock for low-to-low acid flow in the first and second suction towers. (No acid circulation is required during the curing of refractory bricks, but the acid system must be filled and ready for operation at all times. ) 5. Open the manhole of the acid distributor in the drying tower to minimize the amount of atmospheric moisture removed from it. 6. Start the cooling water, which flows through the lubricating oil cooler of the main blower, the boiler feedwater sampling cooler, the blowdown sampling cooler, and the steam sampling cooler. The auxiliary lubricating oil pump must be running, and the lubricating oil heater must be in operation. 7. Switch the on-site valve selector switch to the on position, and open the outlet valve of the main blower. Start the main blower and adjust the speed of the turbine to eliminate the low differential pressure alarm in the sulfur incineration furnace. Since the pressure interlock for low-to-low blower exhaust cannot be satisfied, the on-site selection switch of the outlet valve should be kept in the “on” position. 8. When the exhaust pressure of the main blower is stable, start igniting the burner nozzles. The flame should be as small as possible during the first 24 hours. The air used for combustion must be sufficient at all times to prevent localized overheating of the brick walls. (The driving nozzle system is equipped with flame safety control devices that automatically cut off the fuel supply when the flame goes out or when there is a low differential pressure in the boiler/nozzle.) If the flame goes out, the main blower must be operated at a pressure of 125–150 mm water column for 5 minutes before the nozzle can be ignited again, in order to remove any unburned fuel from the system. ) 9. Continue with the curing of the refractory bricks. During this period, the waste heat boiler is used to control the temperature of the gases discharged through the V-1 start-up chimney. The boiler bypass valve should be opened quickly, and the boiler outlet valve should be opened to 100%. A boiler must be used to prevent the start-up chimney of carbon steel from reaching temperatures above 480°C. The bypass valve and the boiler outlet valve should be operated regularly so that they do not get stuck due to thermal expansion. The fuel gas flow rate control and turbine speed are used to achieve the following heating steps. Its temperature is monitored using the outlet temperature indicator of the sulfur incinerator.  Heat the sulfur combustion furnace; the outlet temperature shall increase at a rate of 14°C/h until it reaches 93°C, and this condition shall be maintained for 24 hours.  Heat at a rate of 14°C/h to 204°C, then maintain for 24 hours. During this time, the boiler began to produce steam. When the pressure reaches 1.75 Mpa, a strong steam flow can be seen at the drum vent, and at this point boiler firing can begin. Close the drum vent and increase the steam temperature until the pressure reaches 7.0 Mpa. Control the outlet temperature of the sulfur burning furnace to maintain boiler pressure and the fuel supply to the startup nozzle. The boiler has started to discharge waste water. The set discharge rate should cause the drum liquid level seen in the sight glass to drop by half every 8 hours. The boiling process will last 24–48 hours. The boiler firing procedure can be modified based on the instructions and recommendations from the boiler manufacturer and water treatment consultants. After the furnace is cooked, the driving nozzle and the main blower should be stopped. The boiler should be drained, and then water should be added several times to flush the system. Check the level gauge sight glass. If the sight glass becomes blurred due to chemical corrosion caused by heating the furnace, it should be replaced. After boiling and rinsing are complete, water is added to the boiler again until the normal water level is reached. Close the check valve and the outlet isolation valve, and open the drum vent valve. Restart the main blower and the start-up nozzle to raise the drum pressure to 1.75 Mpa, then close the vent valve, and open the check valve and the outlet isolation valve. Continue the curing of the refractory bricks.  Heat the sulfur incinerator to 315°C at a rate of 14°C/h, and maintain this temperature for 24 hours. Steam is output through the high-pressure steam main or vented.  Heat the sulfur incinerator to 426°C at a rate of 14°C/h, and maintain this temperature for 24 hours.  Open the continuous blowdown valve to 20% opening and put the atmospheric pressure blowdown expander into operation. Adjust the level regulator to bring the liquid level to the normal operating level.  Heat the sulfur incinerator to 537°C at a rate of 14°C/h, and maintain this temperature for 24 hours. When the outlet temperature of the sulfur incineration furnace reaches 480°C, close the boiler bypass valve.  After the end of these 24 hours, increase the outlet temperature of the sulfur incineration furnace gradually over 8 hours to 870–900°C, and maintain it for 4 hours. The first curing phase for the refractory bricks is now complete. During the curing period of the refractory bricks, monitor the plugs of the sulfur combustion furnace shell. When the steam flow from the brick wall stops, replace the plug. Except during the first start-up of the unit, or after the refractory bricks have been overhauled or become damp, the sulfur incinerator and boiler do not need to be heated at such a slow pace as specified above. They can be gradually heated to 315°C within the first few 8-hour periods, and then gradually heated to 870–900°C within the subsequent few 8-hour periods. VIII. Hot air drying: When the temperature in the sulfur incineration furnace reaches 870–900°C and remains at this level for 3–4 hours, the furnace gases are sent from the sulfur incineration furnace to the converter, thereby starting the heating of the converter. During the heating up period, the driving gas is vented from the manhole (V-2) of the economizer 4C/4A. Dry air is used for dry blowing to provide the initial heat to the converter. Dry blow once at a time to raise the temperature, continuing with dry blowing until the temperature in each section is between 100–170°C. One-time dry blowing reduces the heating time by about 24 hours. 1. Turn off the driving nozzle and stop the main blower. 2. Start the acid circulation pump to circulate acid among the three towers. Start the nicotinic acid tower acid circulation, and pass it through the nicotinic acid boiler; temporarily close the acid separator manhole of the drying tower. During this time, the acid cooler requires cooling water. 3. Determine the positions of the valves, vent valves, and blind flanges according to the contents listed below and those shown in the attached table. Regarding the location of blind flanges and valves.  Remove the blind flange (B-A) on the pipe leaving the waste heat boiler and going to the converter. Remove the driving flue and close the manhole (V-1) on the exhaust boiler outlet pipe.  Open the boiler bypass valve to 100% and open the boiler outlet valve to 5% (BV-1).   Open each valve leading to the 2nd, 3rd, and 4th pipeline sections by 25% (BV-2, BV-3, and BV-4).  Close the cold and hot absorber heat exchanger bypass valves (CV-1 and CV-2). This work must be completed quickly. There should be enough personnel. The blind flange does not need to be fully tightened with bolts. 4. Start the main blower and adjust its speed in order to eliminate the low-low main blower exhaust pressure alarm. 5. Blow dry air into the converter until the temperature at the outlet of the sulfur combustion furnace drops to 400°C. Stop the main blower, and stop the acid and nicotinic acid circulation pumps. Note: The temperature in the converter pipeline must not exceed 600°C. Due to the stresses generated during the heating of the converter, the temperature difference across the 3 partition plates that separate the various sections within the converter must not exceed 140°C. To maintain the temperature within the aforementioned range during all heating stages, it is necessary to adjust the gas flow and gas temperature in each section of the converter as required, including partially closing the boiler bypass valve. The valves in the piping leading to each section also need to be adjusted. 6. If additional dry blowing is required, the positions of the valves, vent valves, and blind flanges should be determined according to the following requirements:  Install a blind flange (B-A) on the pipeline leading from the waste heat boiler to the converter. Open the manhole (V-1) on the boiler outlet pipe. Install the exhaust chimney.  Open the boiler bypass valve to 25%.  Open the boiler outlet valve to 100% (BV-1). Note: The positions of valves, vent valves, and blind flanges in the converter system must not be changed. 7. Open the manhole of the dryer tower distributor. 8. Start the main blower using the same method as when curing the refractory bricks of the sulfur incineration furnace. Ignite the driving nozzle, adjust the turbine throttle valve, and reheat the sulfur incinerator as quickly as possible (at a rate of no more than 110°C per hour) to 870–900°C. At this time, the boiler outlet temperature is approximately 480°C. Maintain at the above temperature for about 1 hour, then return to step 1. IX. Temperature rise due to gas combustion and conversion 1. Determine the positions of valves, vent valves, and blind flanges as indicated in the attached table. After the final dry blow, the valve should be near this position.  Open the boiler outlet valve to 15% (BV-1). Note: The positions of the remaining valves, vent valves, and blind flanges should not be changed. 2. Continue the acid circulation between the drying tower, the first absorption tower, the second absorption tower, and the nicotinic acid tower. Open the manhole in the drying tower at the level of the acid distributor. All coolers begin the water cooling cycle; if the acid temperature rises to 82°C, the cooling tower fans are started. 3. Restart the main blower and ignite the start-up nozzle. The outlet pressure of the fan may rise to 1000–1150 w.g. Use the lowest possible combustion rate to maintain a steady rise in the converter temperature. Note: Keep the temperature of the waste heat boiler outlet and the inlet pipeline of Converter Section 1 below 600°C. Maintain the temperature difference between each segmented plate at less than 140°C. The outlet temperature is controlled using the waste heat boiler outlet valve (BV-1). Use the boiler bypass valve to control the temperature of the pipeline going to Section 1. 4. Maintain the outlet temperature of the sulfur combustion furnace at 870–900°C, while the inlet temperature of stage 1 should be as high as possible to allow heat to accumulate in the converter, but it must not exceed the maximum temperature of 600°C. Continue to pass the combustion gas through the converter until each section of the converter reaches as close as possible to 425°C. The outlet temperatures at stages 1 and 4 should be above 420°C, while the inlet temperatures at stages 2 and 3 should be at least 420°C before sulfur can be introduced. 5. As the converter temperature rises, the exhaust gas from the economizer 4C/4A may become turbid. This is because SO3 gas is released when the catalyst temperature reaches nearly 300°C. A slightly turbid airflow can be seen coming from the chimney of the car. If that is not allowed, then turn off the driving nozzle and the main blower. Remove the blind flanges at the outlet of economizer 4C/4A and the start-up chimney (B-B), and close the manhole of economizer 4C/4A (V-2). Restart the main blower and the start-up nozzle. As the combustion gas flows through the two absorption towers to the chimney, emissions from the startup chimney can be eliminated. 6. During the final heating process, especially when the combustion gas passes through the two absorption towers, the concentration of 98% acid should be checked. At the same time, samples should also be taken for comparison with an acid analyzer. If the concentration is below 93%, the machine should be stopped and the acid replaced. Once the catalyst and sulfur incinerator reach the above temperatures, the plant can be started up for sulfur processing. Stop the fuel supply, stop the main blower, and remove the start-up nozzle. Clean the sight glass and replace the starting nozzle with a sulfur torch. X. Sulfur combustion – corresponding treatment for the sulfur burning and acid systems 1. Once the sulfur spray gun, which was removed during the heating stage, is in place, cooling steam should be turned on as soon as possible. 2. The cooling water in the cooling tower must be in circulation, and the fan must be operating properly. The desalinated water is also in circulation. 3. Determine the positions of the valves, vent valves, and blind flanges according to the points listed below and the attached tables.  Install blind flanges in the heating pipes of each section (B-E, B-F, B-G). Remove the blind flange (B-C) in the pipeline from economizer 3B to the suction tower.   Remove the blind flange (B-B) in the pipeline from the economizer 4C/4A to the secondary suction tower. Close the manhole (V-2) in the outlet pipeline.  Install economizer 3B to remove the blind flanges (B-D) from economizers 4C/4A. Open the waste heat boiler outlet valve to 100% (BV-1).   Set the waste heat boiler bypass valve to 25% open. Close the valves (BV-2, BV-3, BV-4) in the pipes leading to each section.   Close the hot absorber heat exchanger bypass valve (CV-2). The inlet temperature regulator in section 3 must be set to a control temperature of 435°C and placed in the automatic mode.  Close the cold suction tower heat exchanger bypass valve (CV-1). The inlet temperature regulator in section 4 must be set to a control temperature of 420°C, and it should be in the automatic mode. 4. In a concentrated acid system:  Permanently close the manhole at the elevation of the dryer distributor. The three-tower flow regulator is in the automatic position, and its designed control flow rate is to deactivate the low-low flow interlock bypass for the acid flow to the absorption tower.   The liquid level regulator of the acid circulation pump should be set to the designated control value and placed in automatic mode.  The acid concentration regulator in the acid circulation pump tank is set to control 98.5% sulfuric acid and is in automatic mode. Open the isolation valve and close the drain valve at the inlet of the dilution water control valve.  Set the acid temperature regulator for the drying tower to 66°C. Set the acid temperature regulator at the absorption tower to 82°C. Set the water temperature regulator of the deoxygenator to 78°C. Set all regulators to the manual position. Open the control valve of the drying tower to 70% and the control valve of the absorption tower to 100%. Close the acid valve at the outlet of the boiler feedwater preheater. After starting the machine, once the temperatures in each tower reach their designed values, set the dryer tower temperature regulator and the boiler feedwater temperature regulator to automatic mode. When the acid temperature in the absorption tower reaches 82°C again, set the absorption tower temperature regulator to automatic mode. When the temperature of the imported acid reaches 54°C, the anodic protection of the utility acid cooler, the boiler feedwater preheater, and the finished acid cooler is activated. 6. Set the superheater temperature regulator to the design value, and switch both to the automatic mode. 7. Fully open the inlet isolation valve of the sulfur spray gun. A spray gun should be used when starting up the device. 8. The inlet and outlet isolation valves of the sulfur flow control valve must be fully open. 9. The oxygen and SO2 analyzers for chimney exhaust must be in operation. 10. Set the waste heat boiler level regulator to the normal operating level. 11. The acid circulation pump tank must have dilution water. 12. Start the main blower and adjust the turbine speed so that the exhaust pressure is 1000 mm w.c. Immediately start the feed pump for the sulfur incinerator, open the sulfur flow control valve to 50%, and supply sulfur to the sulfur incinerator. When sulfur reaches the sulfur incinerator, the temperature of the gas exiting the incinerator rises immediately. At the same time, the blue flame of sulfur combustion was observed through the sight glass of the sulfur incinerator. If sulfur does not enter the sulfur incinerator in the short term, stop the fan to prevent the sulfur incinerator from cooling down too much. Take the necessary steps to feed sulfur into the sulfur incinerator. 13. Once sulfur has entered the sulfur incinerator, gradually adjust the flow rate and maintain it at 790°C (7–8% SO2). 14. Gradually increase the turbine speed, maintain the feed sulfur at 975–1050°C (10–10.5% SO2), and activate the second sulfur injection gun as needed. When the sulfur gun is put into operation, the sulfur inlet valve should be gradually opened. 15. Maintain this outlet temperature until the inlet temperatures to each section of the catalyst approach normal levels. The outlet temperature in the first section shall not exceed 627°C. (During driving, the operating pressure is low; therefore, the temperature at the first outlet must not exceed 648°C for an extended period of time.) 16. The device must remain stable before productivity can be increased. When improving productivity, the turbine speed should be increased in increments of 100–200 rpm, and the temperature of the sulfur combustion furnace should be adjusted to the design value. Gradually increasing the speed helps reduce process fluctuations.

The company is currently carrying out efforts to reduce costs and improve efficiency; it believes that purchasing sulfur is much cheaper than purchasing sulfuric acid, so it has asked us to get the upgraded sulfur-to-sulfuric acid production facility up and running as soon as possible. I have been busy getting the facility operational these past couple of days, so I haven’t had time to use my computer and therefore didn’t see your post. I’m really sorry about that. Thank you very much for your help!

The person on the second floor is really nice; they explained things in such detail. Learning* here