(92a) The Challenge of Primary Fractionators on NGL Feed

Employing external flux oils and maintaining a minimum volume of naphtha cracking are strategies that are being used by plants originally designed for liquid cracking to compensate for deficiencies in fuel oil as they are being converted to process larger volumes of NGL feeds. The volumes of flux oil or naphtha feed are often established arbitrarily or based on plant behavior. To better understand the deficiencies of processing NGL feed on the operation of a Primary Fractionator, laboratory batch experiments were conducted on Pyrolysis Fuel Oil (PFO) sampled from a plant cracking ethane and propane (E/P).  This PFO was assumed to represent the fuel oil contained in the furnace effluent. The samples were heat stressed at constant temperature for extended periods of time. Viscosity, distillation curves and asphaltene content were analyzed over time.  Volumes of flux oil or requirements for naphtha cracking were established based on the lab experiment. Process simulations were also conducted for evaluating the overall operation of the Primary Fractionator. This paper discusses various challenges expected on the Primary Fractionator by processing larger volumes of NGL feed.