Technical discussion: What is the phenomenon of salt formation in distillation columns?
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This post was last edited by wt2008 on 2015-8-26 07:25. What is the phenomenon of salt formation in distillation columns? Page 243, second line of the second edition of “Technical Questions and Answers on Catalytic Cracking Units”: 66. What is the phenomenon of salt formation in the fractionation tower? When salt deposition occurs in the distillation tower, the following phenomena occur: (1) The adjustment of the tower top temperature becomes inflexible. (2) The number of vacuum occurrences in the tower top circulation return pump has increased significantly. (3) There is severe overlap between gasoline and light diesel. The flash point of the light diesel is not up to standard, and it cannot be adjusted even by using steam from the bottom of the tower. When adjusting using reflux, the issue of unacceptable dry spots reoccurs. (4) When severe salt crystallization occurs, light diesel cannot be extracted. The above phenomena can be used as a basis for determining salt deposition in the fractionation tower. Of course, the above phenomena can also occur in the event of equipment failures such as leaks in heat exchangers (e.g., reboilers at the bottom of stabilizer towers or desorption towers) or the overturning of distillation trays. If it is not a device issue, it should be treated as salt accumulation. May I ask: Is the above statement correct? Everyone is welcome to actively discuss it; there are prizes available.
Voting against it does not mean disapproving of the textbook; after all, it is based on practical experience. However, in today’s world where raw materials are more complex and processing techniques are more sophisticated, some details are no longer as simple as described. There are now many ways to prevent salt buildup at the top of distillation towers, and methods such as raw material desalination and controlling the temperature at the tower top can also help avoid salt formation. As a result, salt buildup rarely occurs, which means that many operators working with distillation towers are not sensitive to this issue. Therefore, the textbook should cover more in-depth methods for preventing salt buildup; it’s time for an update
Supporting opinion: I agree with what is stated in the textbook; it reflects the experience of many refining experts. Although, in today’s environment of more complex raw materials and more sophisticated processing techniques, some details may not match exactly as described, the overall description and the changes in key parameters are still consistent. When such conditions occur in the first stage of the atmospheric distillation column in the atmospheric distillation unit, or in the upper part of the diesel production section in the catalytic unit, it is generally considered to be an instance of salt formation, and preventive measures can be taken accordingly.
The views presented in this book represent an improvement over those in ordinary papers, as it states that \"the aforementioned phenomena can be used as a basis for determining salt formation in distillation columns.\" Of course, the above phenomena can also occur in the event of equipment failures such as leaks in heat exchangers (e.g., reboilers at the bottom of stabilizer towers or desorption towers) or the overturning of distillation trays. ” Ordinary articles are all classified under “salt formation”.
I have encountered such problems in catalytic units before; at that time, water was carried back through the reflux system, causing the pump to run dry. By injecting water through the reflux flow, a gradual washing downward could indeed achieve the desired effect. Today, the pre-treatment of raw materials is done so well that salt accumulation in the distillation columns has not occurred for a long time now. The textbooks indeed need to be revised; for those cases where raw materials are fed in without any pre-treatment, the aforementioned methods remain effective: lol
If it is not caused by leakage, it can indeed be used as a basis for determining salt deposition in the distillation column; such phenomena are indeed rare these days.
Indeed, the authority of \"Technical Q&A on Catalytic Cracking Units\" is beyond doubt; it is one of the essential reading materials for every operator and even technician working in the field of catalysis. Back then, I had just started working in catalysis. It is by studying it that I have gained knowledge. Now, after working for decades, I still take it out to read from time to time; especially when I encounter difficulties in production, I prefer to read it. It can be said that the book \"Q&A on Catalytic Cracking Unit Technology\" is a classic and one of our favorite popular science books.
I personally do agree with the several judgment methods mentioned in the book; at least we had similar ideas back then. (I’ll find the picture and post it!) ) But this kind of situation doesn’t happen very often these days; various organizations also pay considerable attention to such issues. Bro, I originally wanted to use this topic as this week’s agenda. Should we change it instead?
Salt formation in our plant’s fractionation tower is primarily determined by the reaction conditions and the fractionation pressure; if the pressure of the oil and gas entering the fractionation tower differs too much from the pressure at the top of the tower, salt formation may occur. We then check the diesel produced, and on the worst occasions, the diesel that comes out is entirely made up of white salt. I study reactions; I don’t know much about anything else.
The book also states that the salt formation phenomenon varies depending on each type of raw material and equipment; there are similarities as well as differences
I’m just a pawn; I post replies to reap benefits