Crude benzene regulations

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1 Technical regulations 1.1 The temperature at the top of the benzene removal tower shall not exceed 100°C. 1.2 The benzene outlet temperature of the crude benzene condensation cooler is 25-35°C. 1.3 The bottom pressure of the benzene removal tower shall not be greater than 40KPa. 1.4 The temperature at the bottom of the regenerator shall not be less than 170°C. 1.5 The rich oil temperature at the outlet of the tube furnace shall not be less than 180-190℃. 1.6 The water content of rich oil is not more than 1%. 1.7 The distillation volume of crude benzene at 180℃ is 91-92%. 1.8 The temperature of lean oil in the upper tower is 1-2℃ higher than the gas temperature after the final cooling tower in summer and 3-5℃ higher in winter. 1.9 The temperature of superheated steam entering the regenerator is not less than 400℃. 1.10 The lean oil contains benzene not more than 0.5%. The above operational indicators must be recorded in a timely manner, except when the ammonium sulfate section is shut down for maintenance and requires cooling and adjustment in the crude benzene section. 2Equipment OverviewStandard Equipment: Serial No. Name Unit Quantity Specifications 1 Hot lean oil pump unit 2Q=115m3/h H=97m EAP80K2-315 Attached motor unit 2N=55KW n=2900rpm YB250M-2 2 Rich oil pump unit 1Q=110m3/h H=100m ESH80K2-315C Attached motor unit 1N=55KW n=2950rpm YB250M-2 3 Crude Benzene Product Pump Station 2Q=24m3/h H=45m PB65-50-200 Attached Motor Station 2N=7.5KW Comes with flameproof motor 4 Crude Benzene Return Pump Station 2Q=9m3/h H=55m PB40-25-200 Attached Motor Station 2N=5.5KW Comes with flameproof motor 5 oil drain tank self-priming pump platform 1Q=9m3/h H=36 m NTP50-12-50 Attached motor platform 1N=4KW n=2900rpm YB112M-2-W 6 water drain tank self-priming pump platform 2Q=9m3/h H=30m NTP50-12-50 Attached motor platform 2N=4KW n=2900rpm YB112M-2-W 7 Pump room manual monorail crane platform 1Q=1t SDX-3 Attached chain hoist platform 1Q=1t H=5m 8 Oil-gas heat exchanger and condensation cooler platform 2 FN=250m2 9 Poor-rich oil heat exchanger platform 3FN=150m2 10 One-stage lean oil cooler platform 4FN=100m2 11 Two-stage lean oil cooler table 3FN=75m2 non-standard equipment: Serial number name unit quantity specifications 1 benzene removal tower 1DN1800mm H=27622mm 2 regenerator 1DN1600mm H=9000mm 3 cylindrical tube heating furnace 14.652MW-2.45MPa-ø140/ø114 4 new oil washing tank 1DN4900mm H=5585mm VN=90 m3 5 Rich oil tank platform 1DN4900mm H=5585mm VN=90 m3 6 Hot lean oil tank platform 1DN1800mm H=6690mm 7 Coarse benzene intermediate tank platform 2DN2600mm L=6500mm VN=30 m3 8 Oil drain tank platform 1DN1800mm L=6500mm VN=16m3 9 Water drain tank platform 1DN1800mm L=6500mm VN=16m3 10 Benzene removal tower oil-water separator table 1DN600mm H=4200mm 11 Crude benzene oil-water separator table 1DN1400mm H=4500mm 12 Crude benzene reflux tank table 1DN600mm H=4000mm 13 Control separator table 1DN1400mm H=4000mm 14 gas water sealing tank platform 1DN550mm H=2300mm 3. Job operation 3.1 Equipment maintenance 3.1.1 Be familiar with equipment performance, structure, maintenance and operation 3.1.2 Ensure that pumps, motors and other equipment are well lubricated 3.1.3 Check the operation of the equipment every hour 3.1.4 The backup pump should be inspected every shift Turning machine 3.1.5 Ensure the equipment is clean 3.2 Alarm signal 3.2.1 The superheated steam temperature of the outlet tube furnace is ≤ 400°C and the sound and light alarm in the control room 3.2.2 The lower limit of the gas pressure in the tube furnace ≤ 2.5kPa, the sound and light alarm in the control room 3.2. 3. The lower limit of the gas pressure in the tube furnace is ≤ 2kPa. Sound and light alarm in the control room. Close the gas valve. 3.2.4 The upper limit of the regenerator liquid level is ≥ 1800mm. The sound and light alarm in the control room. 3.2.5 The lower limit of the regenerator liquid level is ≤ 200 mm. The sound and light in the control room. Alarm 3.2.6 The upper limit of the liquid level in the new oil washing tank is ≥5000mm, and the sound and light alarm in the control room is 3.2.7 The lower limit of the liquid level in the new oil washing tank is ≤800mm. The sound and light alarm in the control room 3.2.8 The upper limit of the liquid level in the rich oil tank is ≥5000mm, and the sound and light alarm is in the control room. Alarm 3.2.9 The lower limit of the liquid level in the rich oil tank is ≤500mm. The sound and light alarm in the control room. 3.2.10 The upper limit of the liquid level in the hot lean oil tank is ≥4500mm. The sound and light alarm in the control room. 3.2.11 The lower limit of the liquid level in the hot lean oil tank is ≤500mm. The sound and light alarm in the control room. Alarm 3.2.12 The upper limit of the liquid level in the crude benzene intermediate tank is ≥ 1600mm. The audible and visual alarm in the control room starts the crude benzene product pump. 3.2.13 The lower limit of the liquid level in the crude benzene intermediate tank is ≤ 600mm. The audible and visual alarm in the control room stops the crude benzene product pump. 3.2.14 Tank The upper limit of the liquid level in the underground oil venting tank in the oil area is ≥1500mm. Control the indoor audible and visual alarm to start the submersible pump 3.2.15. The lower limit of the liquid level in the underground oil venting tank in the tank area is ≤300mm. Control the indoor audible and visual alarm to stop the submersible pump. 3.2.16 Water venting tank in the tank area. The upper limit of the liquid level is ≥1500mm, control the indoor audible and visual alarm, start the submersible pump 3.2.17 The lower limit of the liquid level of the water drain tank in the tank area is ≤300mm, control the indoor audible and visual alarm, stop the submersible pump 3.3 Normal operation When production is normal, follow the following route for inspection: Underwater underground vent tank → oil-water separator → control separator → crude benzene reflux tank → crude benzene intermediate tank → oil washing tank → rich oil tank → gas water seal tank → tube furnace → regenerator → crude benzene reflux pump → lean-rich oil pump → lean-rich oil heat exchanger → lean oil cooler → oil-gas heat exchanger and benzene condensing cooler → debenzene tower 3.3.1 Underground oil venting and underwater venting tanks must be pumped in time, and full flow is strictly prohibited. 3.3.2 Control the interface of the oil-water separator within the specified range to prevent the separated water from entering the crude benzene and maintain the normal full flow of the benzene reflux tank. 3.3.3 On the day shift on the 15th of every month, the benzene in the control separator is pressed into the oil drain tank. 3.3.4 Measure the liquid level of the crude benzene storage tank during shift handover, accurately measure the crude benzene product output, and strictly prohibit overflow of the crude benzene tank. 3.3.5 Check gas pressure and gas flow frequently to ensure normal discharge of condensate from the gas water seal tank. 3.3.6 Observe whether the flame condition of each burner of the tube furnace is normal. If any unevenness is found, it should be adjusted in time. After extinguishing the fire, the tube furnace must be re-ignited according to the ignition regulations. 3.3.7 Maintain the liquid level in the regenerator, and discharge slag from the regenerator regularly. In case of special circumstances, the slag must be discharged in time, and the pipeline must be cleaned after slag discharge. 3.3.8 Contact the laboratory, take samples in a timely manner and record the results of various tests (mainly benzene in the gas before the tower, benzene in the gas behind the tower, benzene in rich oil, benzene in lean oil, and crude benzene quality), and make timely adjustments based on the test results to ensure that the quality of each product is qualified. 3.3.9 Frequently check the operation and pressure changes of the thermal lean oil pump and rich oil pump, check the temperature and liquid level changes of the oil washing tank and rich oil tank, and make timely adjustments. 3.3.10 Frequently check the oil level of the bearing box of each pump to ensure that the oil level is at 2/3. When the oil level is low, it should be replenished in time. 3.3.11 Check equipment and pipelines frequently for leaks and leaks, and deal with problems promptly if problems are found. 3.3.12 Check the equipment frequently, and turn the spare equipment once per shift. 3.3.13 Maintain equipment and environmental sanitation to ensure clean equipment, clean environment, and no oil pollution on equipment. 3.3.14 Pay attention to the changes in the temperature of the washing oil and gas. Generally, the temperature of the washing oil is controlled to be 1-2°C higher than the gas temperature (3-5°C in winter). 3.3.15 Adjust the water inlet volume of the benzene condensing cooler to ensure that the crude benzene outlet temperature complies with regulations. 3.3.16 Keep the direct steam volume of the benzene removal tower stable, the tower top reflux volume stable, and control the tower top temperature to comply with technical regulations. 3.3.17 Check the steam pressure changes frequently and contact for adjustment in time. 3.3.18 Record the process parameters truthfully every hour, conduct hourly inspections, and deal with any problems found in a timely manner. 3.4 Equipment startup and shutdown 3.4.1 Distillation equipment startup 3.4.1.1 Before starting work, desulfurization, ammonium sulfate, and final cooling must be in normal operation. Check whether the equipment, pipelines, and valves are smooth and in good condition. 3.4.1.2 The gas in the benzene washing tower is running normally. Check that the liquid level in the rich oil tank should be sufficient, and then start the rich oil pump (when the rich oil level is insufficient, new washing oil can be added appropriately), so that the rich oil enters the bottom oil tank through the benzene removal tower. After the oil level reaches 2/3, start the hot lean oil pump, so that the hot lean oil enters the benzene washing tower through the lean oil heat exchanger, the first-stage lean oil cooler, and the second-stage lean oil cooler. 3.4.1.3 After the rich oil at the bottom of the benzene washing tower reaches 2/3 of the liquid level, start the rich oil pump and send it to the rich oil tank. 3.4.1.4 After the lean and rich oil systems start to circulate, attention should be paid to promptly checking whether there are leaks everywhere, adjusting the liquid level within the specified range, and reporting and handling any problems found in a timely manner. 3.4.1.5 After the cycle of lean and rich oil is normal, according to the ignition procedure of the tube furnace, send the torch or the already lit ignition tube into the furnace, then open the furnace gas valve, ignite the tube furnace gas, adjust the gas volume and air inlet volume, and heat and dehydrate the rich oil. The temperature of the tube furnace should be raised slowly. The temperature rise should not exceed 100°C in the first 2 hours. After 4 hours, the temperature can be raised to the specified value. 3.4.1.6 When the rich oil temperature reaches 120°C, direct steam is introduced into the regenerator, and then the oil and gas outlet valve of the regenerator is opened. 3.4.1.7 According to the lean oil temperature, open the cooling water of the first-stage lean oil cooler and the second-stage lean oil cooler, and adjust them to meet the technical requirements. 3.4.1.8 Open the refueling valve of the regenerator, adjust the amount of refueling according to the temperature at the bottom of the regenerator, open the oil-water outlet and oil return port valves at the 29th tray at the top of the tower, and control the crude benzene oil-water separator interface at the top of the benzene removal tower. 3.4.1.9 Control the temperature at the top of the benzene removal tower. When the benzene outlet temperature of the benzene condensation cooler exceeds 30°C, turn on the cooling water. 3.4.1.10 Control the crude benzene oil-water separator interface. When the reflux column is full, start the reflux pump and control the reflux volume to make the tower top temperature meet the regulations. 3.4.1.11 Adjust the temperature, pressure, liquid level and flow rate of each part to meet the technical requirements. 3.4.1.12 According to the operating conditions and test results, the temperature and flow rate of each place are further adjusted to make the crude benzene product qualified. 3.4.2 Shutdown of distillation equipment 3.4.2.1 After receiving the shutdown notice, contact the relevant positions, check whether the drain pipes of each equipment are in good condition and smooth, and make preparations before the shutdown. 3.4.2.2 Close the refueling valve of the regenerator, drain the regenerator residue, and clean the slag discharge pipe. 3.4.2.3 Close each gas burner valve, close the gas main pipe valve, and stop heating of the tube furnace. 3.4.2.4 Close the steam valve entering the tube furnace, the direct steam valve entering the regenerator and the oil and gas outlet valve of the regenerator. 3.4.2.5 When the return tank is not full of flow, stop the return pump and close the pump inlet and outlet valves and the pump cooling water valve. 3.4.2.6 Stop the cooling water of the benzene condensation cooler and the circulating water and low-temperature water of the lean oil cooler. If there is a long shutdown in winter, drain the water accumulated in the equipment and pipes. 3.4.2.7 If the crude benzene section is shut down for a long time, after the rich oil temperature drops to normal temperature, stop the lean oil pump, rich oil pump and rich oil pump in the benzene washing section, and close the pump inlet and outlet valves at the same time. 3.4.2.8 When shutting down for a long time, put the oil in the pipes and equipment into the underground drain tank oil, then introduce it into the rich oil tank, and use steam to clean the oil system equipment and pipes to prevent freezing of the pipes and equipment. 3.4.2.9 Inform the blower station to pay attention to changes in gas pressure, slowly open the gas traffic pipe valve of the benzene washing tower, close the gas inlet and outlet valves, open the diffuser pipe valve, and ventilate steam to clean and set aside. 3.4.3 Start-up of Tube Furnace Two conditions must be met for the start-up and ignition of tube furnace.: ①Rich oil and steam have passed through the furnace tube and are operating normally without leakage. ②The gas water seal is normally full flow and the gas pressure is not less than 3000Pa. 3.4.3.1 Open the gas relief pipe valve, open the scavenging valve until a large amount of steam comes out of the relief pipe, close the scavenging valve, then slowly open the main valve of the gas branch pipe for replacement, wait until gas comes out of the relief pipe, close the relief pipe valve. 3.4.3.2 Strictly check whether all valves, instruments, fire-fighting equipment, etc. are normal. 3.4.3.3 Check whether the gas burner valves are closed. 3.4.3.4 Turn on the fire-extinguishing steam to sweep steam into the furnace until a large amount of steam comes out of the chimney, and then open the flap to 1/3 of the position. 3.4.3.5 Open the main gas valve and drain pipe, drain the condensate, and close the drain valve. 3.4.3.6 When igniting, other personnel must cooperate with the ignition work and light the gas ignition pipe. 3.4.3.7 Put an open gas flame into the gas nozzle of the burner, then slowly open the burner valve. When the gas is burning, take out the ignition tube and light the next nozzle. After lighting them all in sequence, observe whether the gas combustion is normal. If the fire is extinguished, you must re-ignite according to the ignition procedures. 3.4.3.8 After ignition, adjust the gas and air volume, start to heat up, and notify the central control room and the shift leader that the ignition is completed. 3.4.4 Tube furnace shutdown 3.4.4.1 After receiving the shutdown notice from the central control room, close the burner valves and the main branch gas valve. 3.4.4.2 Open the steam valve and purge steam into the furnace to cool down. 3.4.4.3 After a lot of steam comes out of the chimney, close the steam valve. 3.4.4.4 Close each valve of the gas regulating valve. 3.4.5 Start of operation of centrifugal pump 3.4.5.1 With the cooperation of electricians and fitters, check whether the anchor screws are loose and whether all components are in good condition. 3.4.5.2 Check that the lubricating oil should be sufficient and close the pressure gauge control valve. 3.4.5.3 Three weeks of turning went smoothly. 3.4.5.4 Open the inlet pipe valve, fill the inlet pipe and pump body with water, and purify the air. 3.4.5.5 After everything is ready, close and start, slowly open the outlet valve of the pump, then open the pressure gauge control valve, adjust the pressure and flow to the specified requirements. 3.4.5.6 After starting the pump, carefully observe the operation condition and if any abnormalities are found, deal with them promptly or start a backup pump. 3.4.6 Stop the centrifugal pump 3.4.6.1 Close the pump outlet valve. 3.4.6.2 Turn off the pump. 3.4.6.3 Close the pump inlet valve. 3.4.6.4 In winter or when the pump is shut down for a long time, drain the liquid in the pump. 3.4.7 Start of operation of shielded electric pump 3.4.7.1 With the cooperation of the electrician and fitter, check whether the anchor screws are loose, and check whether the instrument pointer on the pump body is in the working area (green is the working area). 3.4.7.2 Close the pressure gauge control valve and open the cooling water valve of the pump. 3.4.7.3 Open the inlet pipe valve, open the exhaust valve on the pump body, and drain the air inside the pump body. 3.4.7.4 After closing and starting, slowly open the outlet valve of the pump, then open the pressure gauge control valve, adjust the pressure and flow to the specified requirements. 3.4.7.5 After starting the pump, carefully observe the operation condition and if any abnormalities are found, deal with them promptly or start a backup pump. 3.4.8 Canned electric pump shuts down 3.4.8.1 Close the pump outlet valve. 3.4.8.2 Turn off the pump. 3.4.8.3 Close the pump inlet valve and the pump cooling water valve. 3.4.8.4 In winter or when the pump is shut down for a long time, drain the liquid in the pump. 4. Special operations 4.1 Power outage operations 4.1.1 Immediately close the gas burner valves, open the fire-extinguishing steam valve to purge steam into the furnace and reduce the furnace temperature. 4.1.2 Open the chimney baffle to the fully open position. 4.1.3 Press the stop button of each pump, close the inlet and outlet valves of each pump, and pay attention to the oil level of each oil tank to prevent tank leakage. 4.1.4 Stop the regenerator for refueling, and close the direct steam valve and oil and gas outlet valve of the regenerator. 4.1.5 Contact the central control room and the shift leader to understand the cause and duration of the power outage. 4.1.6 If the power outage is short, be prepared to start work when the call comes. 4.1.7 If the power outage lasts for a long time, the work should be stopped as normal. In winter, the oil and water in the equipment and pipelines should be drained to prevent freezing damage. 4.2 Steam shutdown operation 4.2.1 If the steam shutdown is planned, the regenerator should drain the residue in advance and clean the slag discharge pipe. 4.2.2 If the steam stops suddenly, close the refueling valve of the regenerator and the oil and gas outlet valve of the regenerator. 4.2.3 Stop the operation of the return pump, close the pump inlet and outlet valves, and the pump cooling water valve. 4.2.4 Contact the central control room and the shift leader to understand the reason for the steam shutdown and the length of the steam shutdown. 4.2.5 In winter, each vent valve of the steam pipeline should be opened, the condensed water in the pipeline should be drained, and the amount of cooling water in the benzene condensing cooler and the lean oil cooler at both ends should be reduced. 4.2.6 Control the liquid level of each oil-water separation tank and make preparations for starting work when steam comes. 4.3 Stopping water 4.3.1 If circulating water is stopped, the amount of low-temperature water can be appropriately increased according to the lean oil temperature to make the lean oil temperature meet the technical requirements. 4.3.2 If the low-temperature water is stopped, causing the benzene outlet temperature of the benzene condensation cooler to exceed the specified limit, it can be treated as a shutdown (the oil system is operating normally). Pay attention to anti-freeze in winter. 4.4 Emergency handling 4.4.1 The heating tube in the tube furnace burned and caught fire 4.4.1.1 Immediately close each burner valve. 4.4.1.2 Open the fire-extinguishing steam valve and sweep steam into the furnace to extinguish the fire. 4.4.1.3 Close all vents, sight holes, and open the chimney damper to the fully closed position. 4.4.1.4 Use steam to clean the oil pipe, and shut down other operations as normal. 4.4.2 When oil pipes and elbows outside the tube furnace leak and catch fire 4.4.2.1 Immediately close all burner valves and use a fire extinguisher to extinguish the fire. 4.4.2.2 When the oil leakage is serious, the work can be stopped after reporting to the duty section leader and obtaining approval. 4.4.2.3 Open the steam valve to clean the oil pipes inside the furnace and the pipes outside the furnace, and open the chimney baffle at the same time. 5. Shift handover system 5.1 Shift succession 5.1.1 Attend the pre-shift meeting on time and listen to the on-duty section leader's introduction to work safety, production, equipment, etc., as well as the precautions and work arrangements of the shift. 5.1.2 Carefully understand the operation status and existing problems of the work equipment. 5.1.3 Check whether the operating indicators of each operating equipment meet the requirements, and check the lubrication of the equipment. 5.1.4 Check the environmental sanitation, equipment sanitation, and the use and storage of materials and tools. 5.1.5 When any violation of procedures or systems occurs, raise and solve the problem in person before handing over 5.1.6 Report to the section leader on duty after handing over 5.2 Shift handover 5.2.1 Take the initiative to introduce the operation status of the equipment and existing problems to the off-duty staff 5.2.2 If there are special operations, they must be adjusted to normal before handing over to the shift 5.2.3 If the indicators are abnormal or an accident occurs, the report should be made and reported to the section leader on duty 5.2.4 When the successor does not arrive at the post to take over, the successor should continue to work until the successor arrives or gets permission from the duty section leader before leaving get off work. 5.2.5 The shift must be handed over at the post, and the situation must be reported to the duty section leader after the shift.