METHOD FOR CONTROLLING SEDIMENTATION IN AN EBULLATED BED PROCESS

摘要

METHOD FOR CONTROLLING SEDIMENTATION IN AN EBULLATED BED PROCESS (D#79,086-F) In an ebullated bed process, it has been found that in switching from one sediment yielding feedstock to a second sediment yielding feedstock that the transient sediment concentration is 5 to 8 times the steady state concentration. Such transients have caused unit shutdowns with lost production time. A method has been found which avoids these high transient sediment concentrations. Second feedstock is added incrementally (1 vol% to 2 vol% of the final rate) over the period of a week or more and sediment in the product analyzed. After full second feedstock rate is achieved, first feedstock is reduced incrementally with sediment analysis. Higher unit utilization is achieved with the corresponding increased yearly production.