Patent ID: 9028655
Filing Date: 2015-05-12
Classification: B01D,C02F,Y10S

Abstract:
1. A closed loop contaminant control system for an evaporative water purification process in an SAGD (Steam Assisted Gravity Drainage) system for a heavy oil recovery facility, the system comprising: an evaporator including a tube side for producing steam and a shell side for producing distilled water, a bottom, a water inlet, at least one distilled water discharge and at least one oil and brine water discharge, a sump provided at the bottom proximate said at least one oil and brine water discharge thereof, an oil skimming weir dividing the sump into a main sump and a blowdown sump, said at least one oil and brine water discharge being located proximate said blowdown sump; a distillate tank for receiving distilled water from said evaporator and for discharging distilled water where said distillate tank has a level controller for controlling 1) the energy supplied to the evaporator and 2) distilled water production; a plurality of controllers comprising: a distilled water flow meter located proximate the at least one distilled water discharge of said evaporator, a blowdown flow meter measuring a flow from the main sump to the blowdown sump, a cycle controller calculating a ratio between a distilled water flow and a blowdown flow; a total flow controller for adjusting a flow of make-up water into said evaporator; a hardness controller for providing a set point of the cycle controller affecting the flow of the make-up water into said evaporator; and a pH controller for adjusting a flow of a caustic to the evaporator sump; wherein a set point for the pH controller is determined by silica concentration in the make-up water.