Thread Content
The importance of the alkali washing tower in the ethylene plant is self-evident. It is related to whether the acid gas can be completely removed and has a crucial impact on the subsequent system. Excessive carbon dioxide leads to blockage of the cold box, and excessive sulfide causes poisoning and deactivation of molecular sieves and catalysts. This not only affects the stable operation of the device, but also affects the quality of ethylene products and the stable operation of polyolefin and other devices. Various problems are encountered during the construction, production, and maintenance of the equipment, including routine problems and unexpected extreme problems. It’s not scary to have problems. What’s most scary is the lack of predictability and relevant and reliable measures to deal with problems. 1. Alkali washing process 2. Alkali washing tower DCS screenshot 3. Alkali washing tower internal parts 4. Alkali washing tower butter sample 5. Alkali washing tower related issues 1. When designing the alkali washing tower system, the gaskets are polytetrafluoroethylene gaskets or polytetrafluoroethylene winding pads. 2. The head problem at the closing point of the alkali washing tower circulation pump led to an upgrade and change in the design pressure level of the system pipelines. 3. The circulation pump mechanical seal is damaged and leaking (self-flushing mechanical seal, external pressure mechanical seal). 4. The downcomer pipes in the strong alkali and medium alkali sections are blocked and the downcomer is not smooth. 5. The opening size of the downcomer in the strong alkali and medium alkali sections is too small, resulting in poor downflow. 6. The content of Na2CO3 and Na2S in the weak alkali section is too high, resulting in crystallization. 7. The pressure difference of the whole tower and each section of the alkali washing tower is high. 8. The pH value of the water washing section is relatively high (design pH is 9.5-10.5). 9. The CO2 at the top of the alkali washing tower exceeds the standard. 10. There are tear holes at the bottom of the water washing, strong alkali and medium alkali sections of the alkali washing tower. At low load, the liquid level cannot be maintained. 11. The liquid at the top of the alkali washing tower enters the next-stage liquid separation tank, causing the compressor to stop at a high liquid level (process design for the gas phase at the top of the alkali washing tower to enter the compressor). 12. The pH value in the gas-liquid entrainment at the top of the alkali washing tower is too high, causing corrosion of the compressor (process design of the gas phase entering the compressor at the top of the alkali washing tower). 13. The pH value in the gas-liquid entrainment at the top of the alkali washing tower is too high and is brought to the liquid separation tank. The alkali in the condensate exceeds the standard, resulting in a reduction in the life of the molecular sieve of the liquid phase dryer (with the design process of the liquid phase dryer). 14. The concentration of waste alkali solution is too high or too low. 15. The temperature of the alkali washing tower is too high, causing hot alkali corrosion (the design of the alkali washing tower is made of non-stainless steel). 16. The oxygen content of fresh alkali is too high, which leads to an increase in butter production (high oxygen content is caused by using non-deoxygenated water with alkali and other reasons). 17. Butter inhibitor injection problem. 18. The impact of continuous injection and discontinuous injection of washing oil on the alkali washing tower. 19. The impact of the circulation volume of the alkali washing tower on the alkali washing effect, tower pressure difference, operating costs, waste alkali treatment capacity, and energy consumption (the processes of different process technologies are very different). 20. The influence of the frequency of butter discharge in the waste alkali section, the discharge method and the design of the discharge process on operability. 21. Effect of alkali concentration and operating temperature on CO2 absorption rate. 22. Whether there is BFW flushing water in the liquid level gauge of each section of the alkali washing tower. 23. When the cracked gas compressor stops unplanned, what is the state of the alkali scrubber system? If there is an unplanned parking period of more than 24 hours, do the sections still need to be run in a loop? If it is not running, will it have any impact on the system? 24. When water circulation is established when the alkali washing tower is started, the liquid level in the tower kettle is too high and does not cross the π bend. 25. When the alkali washing tower system was started, there was a large amount of leakage from the mechanical seal including cracked gas and flange leakage. 26. What are the differences in the butter production mechanisms between methanol to olefins (MTO) and steam cracking to ethylene? How to judge by the color change of butter? 27. What are the operations of emptying and boiling the tower during maintenance of alkali washing tower? Is it necessary to use washing oil to wash the tower? How to judge whether the operation is qualified at each step. 28. What is the impact of ferrous sulfide on the alkali washing tower during maintenance? 29. Alkali washing tower, fresh alkali heating and crystallization, and hot alkali corrosion pipeline problems (regional differences in this area are relatively large). 30. The internal structure of each section of the alkali washing tower and the differences in the design of the alkali washing towers of different process package suppliers. 31. How to adjust the outlet flow of the pump in each section of the alkali washing tower and how to limit the outlet valve? Fully open? Only control the stop valve on the main line? 32. What is the impact of the opening of the anti-surge valve on the alkali scrubber during startup (the design before the anti-surge valve returns to the inlet heater of the alkali scrubber)? Insufficient heating capacity of the superheater leads to blockage of the tower. 33. Alkali emulsification problem of alkali washing tower oil. 34. The alkali washing tower tray overturned. 35. The impact of ultra-high load operation of the alkali washing tower (design maximum 120%, operation maximum 125% or even higher).