Abstract: A method and system for controlling a hydrocracker and fractionator reaction loop is disclosed. The method and system utilizes a sidedraw tray within the fractionator distillation zone upon which liquid is collected. This liquid is withdrawn as a sidedraw stream. The withdrawal of the liquid from the sidedraw tray is controlled based on the level of liquid on the sidedraw tray rather than at a set or determined flow rate. The sidedraw stream is separated into a first stream and a product stream. Unlike other processes where the flow rate of the product stream is set and the internal reflux flow rate varies, the method involves fixing the flow rate of the first stream that is returned to the distillation zone of the fractionators with the flow rate of the product stream being set so as to control the liquid level on the sidedraw tray.

Abstract: A method and system for controlling a hydrocracker and fractionator reaction loop is disclosed. The method and system utilizes a sidedraw tray within the fractionator distillation zone upon which liquid is collected. This liquid is withdrawn as a sidedraw stream. The withdrawal of the liquid from the sidedraw tray is controlled based on the level of liquid on the sidedraw tray rather than at a set or determined flow rate. The sidedraw stream is separated into a first stream and a product stream. Unlike other processes where the flow rate of the product stream is set and the internal reflux flow rate varies, the method involves fixing the flow rate of the first stream that is returned to the distillation zone of the fractionators with the flow rate of the product stream being set so as to control the liquid level on the sidedraw tray.