Produced water treatment system

Abstract

A produced water treatment system includes a skim oil unit, a particulate removal unit, a liquid/liquid separation unit, and a flash concentration unit including a burner for providing hot flue gas into a bath vessel. One or more tubes extending into the bath vessel may be fed hot flue gas by the burner and provide a path for the hot flue gas to flow into the bath vessel. The one or more tubes may include a distribution tube comprising a plurality of ports for hot flue gas to exit the flow path into the bath vessel. At least a portion of a flow path for hot flue gas generated by the burner may extend above a waterline of a bath vessel. Portions flanking the portion of the flow path extending above the waterline may be positioned below the waterline to be thereby submerged during operation. The skim oil unit may include a heated dissolved air floatation system. The heat may be provided by the flash concentration unit. The heat may flash VOCs and dissolved organics from the produced water in a floatation tank of the skim oil. The VOCs and dissolved organics may be provided to the burner for use a fuel and/or incineration.

What is claimed is: 
     
         1 . A flash concentration unit for flashing and concentrating produced water, the flash concentration unit comprising:
 a direct fire bath vessel to receive a supply of solute containing water to concentrate;   a burner configured to combust a fuel to generate hot flue gas that heats the solute containing water within the bath vessel to generate steam and concentrate the solute containing water; and   one or more tubes defining a flow path through which the hot flue gas travels between the burner and a distribution end of the flow path where the hot flue gas is emitted into the bath vessel,   wherein the one or more tubes comprise a distribution tube positioned at the distribution end of the flow path, wherein the distribution tube includes a plurality of ports positioned below a waterline of the direct fire bath vessel and through which hot flue gas exits into the direct fire bath vessel, and wherein at least a first portion of the one or more tubes and corresponding first portion of the flow path extends above the waterline and is positioned between second and third portions of the one or more tubes and corresponding second and third portions of the flow path that extend below the waterline.   
     
     
         2 . The flash concentration unit of  claim 1 , wherein the one or more tubes comprise a fire tube that defines an end of the flow path proximate to the burner, wherein the fire tube is positioned below the waterline to indirectly heat the solute containing water within the direct fire bath. 
     
     
         3 . The flash concentration unit of  claim 2 , wherein the one or more tubes comprise a riser tube that couples to the fire tube and a return tube that couples to the distribution tube, wherein the riser tube extends vertically above the waterline and fluidically couples with the return tube above the waterline, and wherein the return tube extends vertically from above the waterline to below the waterline to couple with the distribution tube. 
     
     
         4 . The flash concentration unit of  claim 3 , wherein the one or more tubes include a u-box return tube that couples between the riser tube and return tube above the waterline.