Key operating points of the MIP process
Thread Content
Our plant is planning to convert the current process of dual lift columns plus dual fractionation towers for olefin reduction into an MIP process. I am the operator in charge of the reaction unit, and after doing some research, I have a basic understanding of MIP technology. I would like to ask: what are the differences between operating with MIP and using traditional lift columns, what are the key points in operation, are there any aspects that are difficult to control, what are the best practices for dealing with accidents, and what determines the flow rate at the outlet of the second reactor? I would appreciate your guidance.
Our plant also plans to transform the current double riser + double fractionator olefin reduction process into an MIP process this year; haha, learning from * as well. There are many relevant posts on the forum.
Catalyst to be regenerated from below the stripping section passes through the catalyst circulation plug valve and returns to the lower part of the second reactor, in order to reduce the space-time velocity in that reactor. Through double inversion, hydrogen transfer and isomerization reactions occur at relatively low reaction temperatures and long contact times, thereby achieving the goal of reducing olefins in gasoline.
Reply to 1# Floating head: The second reaction stage increases the content of isoparaffins and aromatics in gasoline by facilitating hydrogen transfer reactions and isomerization reactions, while reducing the olefin content. However, it also increases the coke yield; therefore, we basically do not use this second reaction stage anymore, maintaining only a small amount of catalyst in circulation, with the temperature in the external circulation tube kept at around 480°C or higher. Reducing gasoline olefins is still mainly achieved through specialized olefin-reducing catalysts. In the case of a reverse flow in the second reactor, it is necessary to prevent abnormal fluidization of the catalyst in the external circulation pipe (catalyst collapse), as this could lead to a sudden increase in the amount of catalyst stored in the second reactor and blockage of the lift pipe. During normal operation, it is important to monitor changes in the total pressure drop across the lift pipe.
We no longer need our second counter! Its main function is to increase the oil-to-agent ratio, lower the reaction temperature, and facilitate hydrogen transfer and isomerization reactions, thereby achieving the goal of reducing olefins in gasoline.
It has a large bulge on the lift pipe, making it much simpler to operate compared to a dual lift pipe. Hehe
There is now the VIP process, which is even better than the MIP process; it also has a large belly but offers a better effect in reducing olefins
When not in use, the secondary reactor of our unit is kept at a certain opening degree; it is needed to reduce olefins when the oil density is high, while it is not utilized when the oil density is low, thereby increasing the liquid yield.