Coking prevention in catalytic settlers
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What other anti-coking measures are available in a catalytic settler besides anti-coking steam?
Superheated steam is used to raise the dead zone temperature of the settler.
When using anti-fogging steam, it is important to ensure that the temperature of the steam is not too low, as this could have the opposite effect. Scale inhibitors and the installation of slurry filters can also be used, but their effects are limited.
Quick cyclone separators are installed for oil and gas exports, and hard connections are used; medium-pressure steam is employed for anti-coking purposes, with the steam temperature being the most important factor to consider
The reasons for coking in sedimentators are quite complex: 1. Anti-coking steam (location, quantity, superheating level); 2. Stripping steam (quantity); 3. Equipment design (VQS, centrifugal separation types: coarse + single centrifuge, etc.); 4. Properties of the feedstock; 5. Reaction temperature, etc. It would be best to take a look at Sinopec’s guidelines for preventing coking
Options available: 1. Efficient rapid separation device； 2. Efficient stripping technology ； 3. The raw materials can be pre-hydrogenated to increase the hydrogen-to-carbon ratio ； 4. Add metal passivators, etc.
The anti-coking steam in the settler can only reduce the problem of coking at the top. Based on our factory’s production experience, the best approach is to increase the stripping steam ； Improve separation efficiency
The increasingly severe properties of the feedstock are the main factor contributing to severe coking. Anticoking steam only has an effect on the dome area; rapid separation devices are installed at the outlet of the riser to minimize the residence time of oil and gas, thereby reducing the reprocessing ratio and the amount of coke formed. Additionally, increasing the amount of stripping steam to lower the partial pressure of oil and gas can also help reduce coking in the settler