I would not consider LCO quench as a technology that reduces transfer line coking. LCO quench should mainly reduce gas yields in the FCC. Regarding transfer line coke, issues could be related to feed injection (poor atomization, feed too heavy), low velocity and cold spots in the OVHD line.
We had a run with 1 out of 8 feed injectors in a poor shape and we saw lots of coke buildup in the transfer line (none in the riser).
