I agree with espana2005, you might have solids accumulation at the end of the header. If the header is the same diameter all the way, the last pass will have a lower flow (speed). The coke will give you problems with the orifice. Does your coker have a strainer inside the fractionator? Or does it have strainers on the suction line of the heater charge pumps? What is the mesh size?(What is the biggest size of coke that can go through?)
Regards
CG
