Liquid sulfur dioxide commissioning procedures

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1 Purpose of test run 1.1 To examine the difference between actual production capacity and designed production capacity through test run. 1.2 Check whether the actual process parameters are consistent with the designed process parameters through test run. 1.3 Examine the performance of the newly installed equipment through commissioning and determine whether it meets the requirements of actual production. 1.4 Examine and solve existing problems in design and construction through test runs. 1.5 Further train job operators and production and technical management personnel through trial runs to make relevant personnel familiar with the production of liquid sulfur dioxide. 2 Conditions that should be met before commissioning 2.1 Various equipment, pipelines, instruments, etc. should be completed in accordance with the requirements of the design and construction drawings and passed the acceptance inspection in accordance with regulations. 2.2 The data that should be handed over to the production unit and the completed data on file should be complete. like: Single-machine installation and debugging qualification data for operating equipment, inspection certificates for measuring instruments, and accompanying documents (instructions, etc.) for outsourced equipment (pumps, etc.). 2.3 The workshop can have normal water supply, electricity, gas and steam. 2.4 The construction site has been cleaned up, the wastewater ditch is unblocked, and the house is in good condition. 2.5 The required commissioning records, shift handover records, etc. should be fully prepared. 2.6 Various raw and auxiliary materials required for test run should be adequately prepared as required. 2.7 The required tooling equipment and effective measuring instruments should be prepared. 2.8 Labor protective gear and technical safety fire-fighting equipment are fully equipped (at least one set of air breathing apparatus should be equipped). 2.9 Corresponding valid technical documents should be in place: Such as the operation method of test driving position, etc. 2.10 Test run personnel are well-equipped, division of labor is clear, and organized by the production unit * The post's "Commissioning Procedures" and "Position Operation Methods", post technical safety, fire protection, environmental protection, etc. can only be taken up after passing the on-site training and assessment. 2.11 Before chemical testing, it must be fully inspected and confirmed by the relevant departments of the company. Only after passing the test can the test run be carried out. 3 Flushing, purging and pressure testing of equipment and pipelines 3.1 Flushing scope 3.1.1 Equipment that should be flushed: Primary absorption tower, desorption tower, desorption kettle, condensation separator, heater, heat exchanger, cooler, recooler, circulation pool, concentrated sulfuric acid cooler, etc. 3.1.2 Pipelines that should be flushed: All liquid material pipes involved in this transformation and the material pipes between the original vacuum pump and the compressor, and the compressor and the aftercooler. 3.2 Flushing Principle 3.2.1 Flush the corresponding flushing equipment one by one until the water is clear and free of impurities. The water should be drained after flushing. If large impurities are observed, they should be cleaned up. 3.2.2 Flush the corresponding flushing pipelines one by one. During flushing, water is injected from above. The pipelines should be disconnected from the equipment, and the equipment nozzles should be blinded with blind plates to prevent impurities and sewage from entering the equipment. Flow meters, traps, etc. on the pipeline should be removed to prevent impurities from entering and causing blockage. 3.3 Purge the steam pipeline system. Use 0.3 ~ 0.5MPa steam to purge the steam system, and purge according to the flushing principle step by step. The purging medium is clean and free of impurities, which is considered qualified. 3.4 The equipment and pipelines from the analytical kettle to the compressor inlet section should be subjected to a vacuum pressure holding test. The pressure holding vacuum value is -0.02MPa. If the vacuum value is not greater than -0.01MPa after 1 hour of pressure holding, it is qualified. 4 Calibration 4.1 The equipment that should be calibrated is: Sulfuric acid circulation tank and circulation pool. 4.2 The above equipment should be calibrated accurately to 500L, and the upper and lower limits of process control should be marked on the scale. 5 Water test run 5.1 After the single machine water test run equipment pipeline is cleaned, the single machine water test run should be carried out for the pickling tower circulation system, primary absorption tower circulation system, secondary absorption tower circulation system and desorption tower circulation system. Check whether the operation of each circulation pump, tower, heat exchange equipment and pipelines meets the process requirements. 5.2 System water test 5.2.1 Test scope includes: Primary absorption system, secondary absorption system, desorption system. 5.2.2 Add water to each circulation pool to 5000~10000L, and start the primary circulation pump, secondary circulation pump, and desorption circulation pump in sequence, and maintain the liquid level balance in each circulation pool. 5.2.3 After the water level in each circulation pool is stable, stop the operation of each circulation pump and disconnect the gas outlet pipe of the condensation separator. 5.2.4 Gradually add steam to the desorption kettle to heat the water in the kettle. When the water temperature in the kettle reaches 95°C, start each circulation pump to start the system water circulation, and gradually adjust the water volume to 20~22m3/h. Observe the parameter changes at each process control point of the heater, desorption kettle, heat exchanger, cooler, and recooler, and make records. 6 Chemical test run 6.1 Chemical test run conditions 6.1.1 System water test run is running normally ； Problems discovered during the water test have been resolved promptly ； The water in each equipment and pipeline has been drained and dried with air, and the relevant process pipelines have been restored correctly. 6.1.2 The site is clean and tidy, and no unclean matter enters the circulation pool. 6.1.3 The sulfur dioxide supply system for sulfuric acid manufacturing operates normally. 6.2 Overview of the process flow The SO2 gas drawn from the outlet of the sulfuric acid manufacturing waste heat boiler is further cooled by the casing cooler and then enters the pickling tower. The SO2 gas entering the pickling tower is in counter-current contact with the 95% sulfuric acid poured down in the packed tower to remove SO3 and other impurities. The 95% sulfuric acid in the pickling tower flows from the bottom of the tower to the sulfuric acid manufacturing 95% sulfuric acid circulation tank. The pickled raw material gas enters the bottom of the first-level absorption tower from the top of the pickling tower, and is in counter-current contact and absorption with the absorption liquid sprayed from the top of the tower in the first-level absorption packed tower. The absorbed rich liquid flows from the bottom of the primary absorption tower to the desorption circulation pool. The absorbed gas enters the bottom of the secondary absorption tower from the top to be absorbed again. The absorbed liquid enters the primary absorption circulation pool from the bottom of the secondary absorption tower. The absorbed tail gas is sent from the top of the secondary absorption tower to the sulfur tail gas absorption tower for treatment and then emptied. After the absorbed rich liquid in the desorption pool is pumped up by the self-priming pump, it first exchanges heat with the desorbed high-temperature lean liquid through a heat exchanger, then enters the heater, and is further heated to 90-100°C with steam, and then enters the packed desorption tower from the top for desorption. The desorbed liquid enters the desorption kettle from the bottom of the tower and is indirectly heated with steam for further desorption. After the desorption lean liquid is reduced to 30~40℃ through the heat exchanger, cooler and recooler, it enters the secondary absorption circulation pool to recirculate and absorb SO2 gas. The SO2 gas desorbed from the desorption kettle and desorption tower is sent to the condensation separator and gas-liquid separator for gas-water separation under the action of vacuum. It is then dried with primary and secondary sulfuric acid, defoamed by a vacuum-wrapped wire mesh, and then sent to the compressor by a vacuum pump. After cooling, it enters the finished liquid sulfur dioxide storage tank. 6.3 Quality indicators (see Table 1) Table 1 Quality indicators of liquid sulfur dioxide finished products Indicator name Quality indicator Appearance Colorless or slightly yellow transparent liquid SO2 (%), ?≥ 99 Non-volatile matter (%), ≤ 1 6.4 Process conditions Pickling tower gas inlet temperature: ≤100℃ Pickling tower gas inlet pressure: ≤15KPa pickling tower gas outlet pressure: ≤13KPa primary absorption tower inlet gas temperature: ≤60℃ primary absorption tower outlet gas pressure: ≤11KPa PH value of desorption liquid at the outlet of primary absorption tower: 3～3.5 Desorption liquid temperature at the outlet of the primary absorption tower: ≤50℃ primary absorption circulation pool liquid level: 5000L～10000L PH value of desorption liquid at the outlet of secondary absorption tower: 3～4 Desorption liquid temperature at the outlet of the secondary absorption tower: ≤50℃ secondary absorption circulation pool liquid level: 5000L～10000L Concentrated sulfuric acid cooler outlet acid temperature: ≤50℃ sulfuric acid circulation tank liquid level: 5000~8000L Amount of acid sprayed by a dry tower: 4～5m3/h Acid spray volume of two dry towers: 3～4m3/h Acid temperature at the outlet of the primary drying tower: ≤50℃ secondary drying tower outlet temperature: ≤50℃ primary and secondary drying tower spray acid concentration: 92%～96% heater outlet liquid temperature: 90～100℃ steam pressure: 0.2～0.5 MPa desorption liquid circulation volume: ≤22 m3/h desorption tower top temperature: 90～100℃ Gas outlet pressure of desorption kettle: -0.01～-0.02MPa desorption tank liquid phase temperature: 95～110℃ Condensation separator outlet gas temperature: ≤60℃ vacuum bag pressure: -0.01~-0.02MPa Gas-liquid separator outlet gas pressure: -0.01～-0.02MPa Recooler outlet lean liquid PH value: ≥4 Recooler outlet lean liquid temperature: 30～40℃ Compressor oil pressure: 0.2～0.4 MPa Compressor primary air inlet temperature: ≤40℃ compressor first stage outlet temperature: ≤100℃ Compressor secondary air inlet temperature: ≤40℃ compressor secondary air outlet temperature: ≤120℃ compressor first stage inlet pressure: -0.01～0MPa compressor first stage outlet pressure: ≤0.50MPa compressor secondary outlet pressure: ≤0.80MPa liquid sulfur dioxide finished product tank temperature: ≤45℃ liquid sulfur dioxide finished product tank pressure: ≤0.8 MPa liquid sulfur dioxide finished product tank liquid storage capacity: ≤85% 6.5 Commissioning steps 6.5.1 Use clean water to prepare an appropriate amount of absorption liquid in the primary absorption circulation pool and the secondary absorption circulation pool. The concentration of the absorption liquid preparation is 20%. 6.5.2 Inform the instrument personnel to turn on each indicating instrument. 6.5.3 Perform liquid circulation on the pickling tower, primary absorption tower, and secondary absorption tower system in sequence. After the circulation is normal, gradually open the sulfur dioxide gas valve to supply raw gas to the system, and gradually adjust the amount of circulating liquid and raw gas to the flow rate required by the process. Use pH test paper to check the pH value of the absorption liquid at the outlet of the primary and secondary absorption towers every half hour. 6.5.4 When the pH value of the absorption liquid at the outlet of the primary absorption tower reaches the process requirements, the absorption liquid from the primary absorption tower can be discharged into the desorption circulation pool, and the liquid level of the primary absorption circulation pool is replenished by the secondary absorption system. 6.5.5 After the desorption circulation tank reaches the specified liquid level, first turn off the raw gas, then stop the pickling system and the primary and secondary absorption systems. 6.5.6 Supply acid to the primary and secondary drying towers, start the vacuum pump and compressor (the gas before there is no sulfur dioxide is evacuated from the finished product tank), and adjust the vacuum to the specified range of the process. Then start the desorption circulation pump to supply the rich liquid to the desorption tower and desorption kettle, and stop the pump when the heating coil in the desorption kettle is submerged. 6.5.7 Slowly pass steam into the desorption kettle to heat up the liquid in the desorption kettle. ； Properly supply cooling circulating water to the condensation separator to control its outlet gas temperature ； Appropriately supply steam to the heater to heat up the absorption liquid. When the liquid temperature in the desorption kettle rises to the process requirements, start the desorption circulation pump to maintain the normal circulation of the absorbent liquid in the desorption system. While ensuring the desorption process conditions, gradually adjust the flow rate to the process requirements. At the same time, supply circulating water to the cooler and recooler, operate the pickling system, the first and second absorption systems according to the method in 6.5.3, and maintain the liquid level balance of each circulation tank in the absorption and desorption systems. The entire system returns to normal operation. 6.6 Other operations 6.6.1 When the shutdown time exceeds 1 day, all the rich liquid must be desorbed and stored in a lean liquid state to prevent contamination. The desorption liquid in each equipment of the desorption system should be exhausted. 6.6.2 The filling method of liquid sulfur dioxide bottling, the filling amount and the corresponding cylinder usage requirements should be clarified in the operating method. 7. List of analysis items (see Table 2) Table 2 List of analysis items Sample name Analysis item Control scope Sampling period Sampling location Sampler Analyst The appearance, SO2 content, and non-volatile matter of liquid sulfur dioxide are shown in Table 1. Randomly inspect the finished product storage tank once a month to inspect the engineering and chemical room. This post was last edited by tyn565 on 2009-4-15 08:57 ]