Compact evaporator for modular portable SAGD process

A method for purification of water in a Steam Assisted Gravity Discharge (SAGD) system using a compact evaporator system comprising the steps of:

• a) providing a compact evaporator system including two vertical falling film heat exchangers each including tubes and a sump, a compressor for circulating steam into both heat exchangers, a compressor suction drum for protecting the compressor from entrained liquid contamination, a distillate tank for collecting hot distilled water produced from the vapor from the heat exchangers, a recirculation pump for circulating brine from the evaporator sump of each of the heat exchangers back to the heat exchangers, wherein the compact evaporator system receives produced water from the SAGD process and make-up water which are fed into the evaporator sump of the respective heat exchanger for providing water to feed a boiler;
• b) introducing a produced water and a make-up water into the sumps of each heat exchanger of the compact evaporator system;
• c) collecting residual water from each of the falling film heat exchangers into the respective sump,
• d) pumping the liquid from the sump of each falling film heat exchanger into a top of a tube side of each of the falling film heat exchangers;
• e) collecting steam created in the evaporator sump on the tube side of each heat exchanger and routing said steam into the suction drum;
• f) compressing the steam from the suction drum via the compressor and routing said steam to a shell side of each heat exchanger;
• g) collecting the condensed steam from the shell side of each heat exchanger into the distillate tank;
• h) skimming a top layer of a brine comprising oil and other impurities via a weir positioned in the respective sump of each heat exchanger;
• i) transferring the skimmed brine to a brine storage;
• and
• j) using the water from the distillate tank to:
• i) feed water to the boiler or ii) recycle water back to the evaporator sump of the respective heat exchanger, wherein the tube has i) a maximum height such that when evaporating water from brine, solids do not substantially precipitate out, ii) a minimum height such that brine is distributed substantially evenly through the tubes, and iii) a maximum height such that the system is transportable.