Heat exchanger and method for heating a fracturing fluid

Abstract

A heat exchanger comprises a shell internally divided into a hot fluid vessel and a cold fluid vessel by a pipe retaining plate having a plurality of apertures sealingly retaining a corresponding number of heat pipes, each of which has a hot end in the hot fluid vessel and a cold end in the cold fluid vessel. The hot fluid vessel is internally configured to direct a hot fluid through a porous dispersion plate that distributes the hot fluid amongst the hot ends of the heat pipes. The cold fluid vessel has an internal baffle that defines a serpentine channel that guides a cold fluid through the cold fluid vessel. Fracturing fluid may be heated by streaming flue gas exhausted from an incinerator through the hot fluid vessel while simultaneously streaming the fracturing fluid through the cold fluid vessel.

1 . A heat exchanger for exchanging heat from a hot fluid to a cold fluid, the heat exchanger comprising:
 (a) a shell having a hot fluid inlet, a hot fluid outlet, a cold fluid inlet, and a cold fluid outlet;   (b) a pipe retaining plate internally dividing the shell into a hot fluid vessel defining a hot fluid flow path from the hot fluid inlet to the hot fluid outlet, and a cold fluid vessel defining a cold fluid flow path from the cold fluid inlet to the cold fluid outlet;   (c) a plurality of spaced-apart heat pipes, each of the heat pipes seemingly retained through a corresponding aperture in the pipe retaining plate, and having a hot end disposed in the hot fluid vessel, and a cold end disposed in the cold fluid vessel;   (d) a porous dispersion plate in the hot fluid vessel disposed between the hot fluid inlet and hot ends of the plurality of heat pipes for dispersing the hot fluid evenly among the hot ends of the plurality heat pipes;   
       wherein the hot fluid vessel is internally configured so that the hot fluid flow path passes through the porous dispersion plate before passing about the hot ends of the heat pipes and through the hot fluid outlet. 
     
     
         2 . The heat exchanger of  claim 1  wherein the shell comprises a pressure vessel. 
     
     
         3 . The heat exchanger of  claim 1  wherein the shell comprises a vacuum chamber with a vacuum port. 
     
     
         4 . The heat exchanger of  claim 1  wherein the shell is substantially rectangular prismatic or cylindrical in shape. 
     
     
         5 . The heat exchanger of  claim 1  further comprising at least one baffle in the cold fluid vessel and configured to define a serpentine channel for the cold fluid flow path. 
     
     
         6 - 8 . (canceled) 
     
     
         9 . The heat exchanger of  claim 1  wherein each heat pipe comprises a sealed tube containing a heat transfer substance that migrates from the hot end to the cold end when the heat transfer substance is at a higher temperature, and migrates from the cold end to the hot end when the heat transfer substance is at a lower temperature. 
     
     
         10 - 13 . (canceled) 
     
     
         14 . The heat exchanger of  claim 1  wherein the hot fluid inlet is adapted for connection to the exhaust of an incinerator. 
     
     
         15 . The heat exchanger of  claim 1  wherein the dispersion plate is adapted for dispersing a flue gas. 
     
     
         16 . The heat exchanger of  claim 1  wherein the heat pipes have a finned internal surface, a finned external surface, or both. 
     
     
         17 . The heat exchanger of  claim 1  wherein the heat pipes have a finned external surface adapted for oil emulsion breaking or waste water treatment. 
     
     
         18 . A method of using the heat exchanger of  claim 1  to heat a fluid with flue gas, the method comprising the continuous and simultaneous steps of:
 (a) using an incinerator to combust a fuel to generate a flue gas exhaust stream; 
 (b) directing the flue gas exhaust stream through the hot fluid inlet; 
 (c) pumping a fluid stream through the cold fluid inlet; and 
 (d) controlling the flow rate of the flue gas exhaust stream, the fluid stream, or both so that the fluid at the cold fluid outlet is heated to a target temperature. 
 
     
     
         19 . The method of  claim 18  wherein the incinerator is a cyclonic incinerator. 
     
     
         20 . The method of  claim 18  wherein the fluid is fracturing fluid and the target temperature is at about 50° C. 
     
     
         21 - 22 . (canceled) 
     
     
         23 . The method of  claim 18  further comprising the continuous and simultaneous step of drawing a vapor from the cold fluid vessel through a vapor port. 
     
     
         24 . The method of  claim 23  wherein the vapor is drawn through the vapor port to create a vacuum in the cold fluid vessel. 
     
     
         25 . The method of  claim 23  further comprising the step of flowing the vapor from the vapor port to the incinerator for combustion. 
     
     
         26 . The method of  claim 18  further comprising the steps of flowing the cold fluid through the cold fluid outlet to a vacuum chamber and drawing a vapor from the cold fluid. 
     
     
         27 . The method of  claim 26  wherein the vacuum chamber is maintained under a vacuum. 
     
     
         28 . The method of  claim 26  further comprising the step of flowing the vapor from the vacuum chamber to the incinerator for combustion.