Maintenance of the alkylation unit; the product pipelines are severely blocked
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This post was last edited by Guan Gongyu on 2016-5-23 08:58. During the maintenance of our alkylation unit, we were surprised to find that the product pipelines were severely clogged – almost completely blocked in fact – so we had to cut them off section by section. The pickling tower is also heavily clogged; there’s so much sludge that it’s like a coal mine, over two meters deep. Why is this? How did it happen?
I remember that before shutting down, we raffined some gasoline produced by the asphalt unit in front of the pickling tower, with the aim of removing sulfur; could this be related to coking?
Will the acid cleaning tower in the alkali solution line suffer from severe coking?
May I ask if the time product analysis before parking is normal? Also, should there be any changes in the product quality flow meter? Shouldn’t alkylated products coking?
Before shutting down, we reprocessed some gasoline from the asphalt unit in front of the pickling tower, with the aim of desulfurization. Will the acid cleaning tower in the alkali solution line suffer from severe coking?
Our dry point is between 210 and 205, sometimes it goes a bit higher to around 214. I don’t know why, but I kept at it; the manager said it’s around 205 outside.
There are several reasons for high dryness: 1, uneven mixing due to issues with the reactor internals. 2, an excessively low alkene-to-olefin ratio. 3. The impurities in the feedstock, such as dienes, and the content of C5 compounds are too high. 4. The acid-to-hydrocarbon ratio is too high or the acid concentration is low. 5. The reaction temperature is too high, meaning the operating load is excessive.
Secondly, I believe it is inappropriate to use alkylation acid washing equipment to treat oxidized asphalt sludge, as this type of sludge is unstable and tends to react with concentrated sulfuric acid to form acid residues (similar to the old acid-base refining process); this is likely the reason for blockages in the equipment and pipelines.
Thank you for your reply; it seems similar to our situation.
Are you joking? Hehe. . . . . . Is the blockage in the product pipeline caused by a lot of black substance that is gel-like? Similar to asphalt. Welcome to the technical exchange group for alkylation and spent acid units – let’s discuss and share knowledge together: 546996393