I'm working in ExxonMobil licensed FlexiCracking unit. After emergency shutdown in unit, Slurry PA, HCO PA, LCO PA flows are disturbing. Slurry PA flow is establishing after 2 - 3 trials. Whereas LCO PA & HCO PA were unable to maintain even after opening cutter to both the circuits. Immediately after unit trip, we are closing stripping steam to LCO, HCO strippers, LCO PA, HCO PA pumps are drained thoroughly before placing it in service. LCO PA, HCO PA are slowly dropping to zero. that time main fractionator top temp increasing too high to >170 C. How can I maintain steady LCO PA, HCO PA flows during unit startup, while maintaining main column top temp at 140 C. Please help me how can i maintain steady PA flows during startup so that MF temp profile is steady.