Heat Exchanger for an Oil Storage Tank

Abstract

A heating assembly for heating a liquid storage tank includes a heat exchanger tank supported in one wall of the storage tank to extend into the storage tank in contact with liquid stored therein. The heat exchanger tank contains a heat exchanger fluid therein which is heated by a heating apparatus extending through the heat exchanger tank whereby heat is only transferred to the liquid in the storage tank through the heat exchanger fluid. The heating apparatus extending through the heat exchanger tank may be a burner tube or an electrical resistance-type heating element according to different embodiments of the invention.

1 . A heating assembly for heating a liquid storage tank having walls surrounding a hollow interior arranged to contain a liquid therein, the assembly comprising:
 a heat exchanger tank including boundary walls containing a heat exchanger fluid therein;   a heating apparatus supported within the heat exchanger tank;   the heat exchanger tank being arranged to be supported within the liquid storage tank such that heat from the heating apparatus is arranged to be communicated through the heat exchanger fluid and the boundary walls of the heat exchanger tank directly to liquid in the liquid storage tank.   
     
     
         2 . The assembly according to  claim 1  wherein the heat exchanger tank is arranged to be supported within the oil storage tank such that heat is only communicated from the heating apparatus to the liquid in the storage tank through the heat exchanger fluid. 
     
     
         3 . The assembly according to  claim 1  wherein the heat exchanger tank is arranged to be supported in sealing engagement with one of the walls of the oil storage tank. 
     
     
         4 . The assembly according to  claim 1  wherein the heat exchanger tank is arranged to extend generally horizontally inward from an upright boundary wall of the storage tank. 
     
     
         5 . The assembly according to  claim 1  in combination with a production tank arranged to receive produced hydrocarbons therein directly from a well. 
     
     
         6 . The assembly according to  claim 1  further comprising an overflow tank located externally of the heat exchanger tank and an overflow passage in communication between the overflow tank and the heat exchanger tank so as to be arranged to permit expansion of the heat exchanger fluid from the heat exchanger tank into the overflow tank. 
     
     
         7 . The assembly according to  claim 1  further comprising a fluid level monitor arranged to monitor a level of heat exchanger fluid in the heat exchanger tank, and a controller arranged to cease operation of the heating apparatus responsive to a level of the heat exchanger fluid as monitored by the fluid level monitor falling below a prescribed lower level limit. 
     
     
         8 . The assembly according to  claim 1  further comprising a heat exchanger temperature monitor arranged to monitor a temperature of the heat exchanger fluid in the heat exchanger tank, and a controller arranged to cease operation of the heating apparatus responsive to a temperature of the heat exchanger fluid as monitored by the heat exchanger temperature monitor exceeding a prescribed upper temperature limit. 
     
     
         9 . The assembly according to  claim 1  further comprising a heat exchanger temperature monitor arranged to monitor a temperature of the heat exchanger fluid in the heat exchanger tank, and a controller arranged to actuate operation of the heating apparatus responsive to a temperature of the heat exchanger fluid as monitored by the heat exchanger temperature monitor falling below a prescribed lower temperature limit. 
     
     
         10 . The assembly according to  claim 1  further comprising a storage temperature monitor arranged to monitor a temperature of the liquid in the liquid storage tank, and a controller arranged to cease operation of the heating apparatus responsive to a temperature of the liquid as monitored by the storage temperature monitor exceeding a prescribed upper temperature limit. 
     
     
         11 . The assembly according to any one of  claims 1  through  10  wherein the heat exchanger tank includes a perimeter flange projecting outwardly from the boundary walls about a circumference of the heat exchanger tank, the perimeter flange being arranged to be mounted in sealing engagement about a perimeter of an opening in the wall of the oil storage tank. 
     
     
         12 . The assembly according to  claim 11  wherein the perimeter flange is defined by a perimeter edge of an end wall at one end of the heat exchanger tank. 
     
     
         13 . The assembly according to  claim 11  wherein the perimeter flange includes spaced apart mounting apertures formed therein so as to be arranged to secure the flange to the perimeter of the opening in the wall of the oil storage tank using threaded fasteners. 
     
     
         14 . The assembly according to  claim 1  wherein the heat exchanger fluid comprises heat transfer oil. 
     
     
         15 . The assembly according to  claim 1  further comprising a production passage communicating through the heat exchanger tank from an inlet end of the production passage arranged to receive produced fluid from a well therein to outlet of the production passage arranged for communication with the hollow interior of the storage tank such that the production passage is in heat exchanging relationship with the heating apparatus through the heat exchanger fluid. 
     
     
         16 . The assembly according to  claim 15  wherein the production passage follows a sinuous path through the heat exchanger tank. 
     
     
         17 . The assembly according to  claim 15  wherein the production passage is above the heating assembly. 
     
     
         18 . The assembly according to  claim 1  wherein the heating apparatus comprises a burner tube extending through the heat exchanger tank and being arranged to be coupled to an external burner so as to direct exhaust from the burner therethrough. 
     
     
         19 . The assembly according to  claim 1  wherein the heating apparatus comprises an electrical resistance-type heating element extending through the heat exchanger tank. 
     
     
         20 . A method of producing hydrocarbons from a well comprising a wellhead, the method comprising:
 providing a storage tank in proximity to the well having an interior storage chamber for storing produced hydrocarbons therein;   providing a heating assembly comprising:
 a heat exchanger tank received within the interior of the storage chamber of the storage tank, the heat exchanger tank including boundary walls containing a heat exchanger fluid therein; and 
 a heating apparatus supported within the heat exchanger tank; 
   directing produced hydrocarbons from the well into the interior storage chamber of the storage tank; and   heating the produced hydrocarbons in the interior storage chamber of the storage tank by actuating the heating apparatus such that heat from the heating apparatus is arranged to be communicated through the heat exchanger fluid and the boundary walls of the heat exchanger tank directly to the produced hydrocarbons in the storage tank.