Coaxial and side-by-side catalytic cracking
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In coaxial catalytic cracking, when opening the large blind flanges during startup, it is necessary to stop feeding main air to the regenerator, with the main fan operating in safety mode; whereas in the high-low parallel configuration, there is no need to stop the main fan, and the supply of air can continue, right? Thank you!
If necessary, indicate that if the requirements of the previous sections are met, removal may not be necessary!
Even if they are coaxial, it won’t ensure the safe operation of the main airflow; that would be troublesome, as the catalyst could flow back
We are in co-axial operation; the double-acting slide valve is fully open, the air flow is set to its minimum level. The valve is then closed completely to cut off the connection between the two units. All steam supply points connected to the settler are shut off, and the vents at the top as well as those for oil and gas are opened in order to install the blind flanges
To prevent catalyst leakage from the special valve, it’s necessary to keep the two vessels connected; moreover, the settler should not be under pressure. If the pressure difference between the two vessels is too large, the catalyst will accumulate at the bottom of the lift pipe, which can cause problems