Crude oil desalter dehydration vessel

Abstract

A system for removing salt from oil includes a vertically oriented desalting vessel, a crude oil entry located at a bottom of the desalting vessel in fluid communication with the top crude oil layer, a pair of electrode plates positioned vertically in the top crude oil layer, at least one ground plate inside the desalting vessel, a water outlet located on the bottom of the desalting vessel, and a treated oil outlet located at a top of the desalting vessel. A method for removing salt from crude oil includes providing a crude oil mixture into a vertically oriented desalting vessel, applying an electric field through a pair of electrode plates, collecting treated oil from a treated oil outlet located at a top of the desalting vessel, and collecting water from a water outlet located on the bottom of the desalting vessel in fluid communication with the bottom water layer.

What is claimed: 
     
         1 . A system for removing salt from oil, the system comprising:
 a vertically oriented desalting vessel configured to contain a fluid, the fluid comprising a top crude oil layer, a middle emulsion layer, and a bottom water layer;   a crude oil entry located at a bottom of the desalting vessel and in fluid communication with the top crude oil layer;   a pair of electrode plates positioned vertically in the top crude oil layer, each plate being in electrical communication with an electrical transformer;   at least one ground plate inside the desalting vessel;   a water outlet located on the bottom of the desalting vessel and in fluid communication with the bottom water layer; and   a treated oil outlet located at a top of the desalting vessel and in fluid communication with the top crude oil layer.   
     
     
         2 . The system of  claim 1 , further comprising an interface level device positioned in the middle emulsion layer, wherein the interface level device is in communication with an interface level transmitter. 
     
     
         3 . The system of  claim 1 , wherein a ground plate of the at least one ground plate is positioned between the pair of electrode plates in the top crude oil layer. 
     
     
         4 . The system of  claim 1 , wherein the pair of electrode plates are comprised of metal. 
     
     
         5 . The system of  claim 1 , wherein each electrode plate of the pair of electrode plates has a length ranging from 35% to 50% of a height of the desalting vessel. 
     
     
         6 . The system of  claim 1 , wherein a length of at least one of the at least one ground plate ranges from 40% to 50% of a height of the desalting vessel. 
     
     
         7 . The system of  claim 1 , wherein each electrode plate of the pair of electrode plates are rectangular. 
     
     
         8 . The system of  claim 7 , wherein dimensions of the pair of electrode plates 4.5 m×3.3 m×2.5 cm. 
     
     
         9 . The system of  claim 8 , wherein the pair of electrode plates are 7.5% of a height of the desalting vessel from the top of the desalting vessel. 
     
     
         10 . The system of  claim 8 , wherein a face of each member of the pair is 25% of a diameter of the desalting vessel from a closest wall of the desalting vessel. 
     
     
         11 . A method for removing salt from crude oil, the method comprising:
 providing a crude oil mixture into a vertically oriented desalting vessel via a crude oil entry located at a bottom of the desalting vessel, wherein the desalting vessel comprises a pair of vertically oriented electrode plates;   applying an electric field through the pair of electrode plates such that water droplets in the crude oil mixture coalesce and fall to a bottom of the desalting vessel, thereby forming a top crude oil layer, a middle emulsion layer and a bottom water layer;   collecting treated oil from a treated oil outlet located at a top of the desalting vessel and in fluid communication with the top crude oil layer; and   collecting water from a water outlet located on the bottom of the desalting vessel and in fluid communication with the bottom water layer.   
     
     
         12 . The method of  claim 11 , wherein the collecting treated oil and the collecting water are conducted continuously. 
     
     
         13 . The method of  claim 11 , further comprising:
 monitoring a level of the middle emulsion layer via an interface level transmitter, wherein the interface level transmitter is in communication with an interface level device positioned in the middle emulsion layer.   
     
     
         14 . The method of  claim 11  further comprising:
 introducing additional crude oil mixture to the vessel to maintain a fluid level in the vessel above a top of the pair of electrode plates. 
 
     
     
         15 . The method of  claim 11 , wherein the pair of electrode plates are rectangular. 
     
     
         16 . The method of  claim 11 , wherein the pair of electrode plates have a length that is in a range of 35% to % of a height of the desalting vessel. 
     
     
         17 . The method of  claim 11 , wherein the pair of electrode plates are comprised of metal. 
     
     
         18 . The method of  claim 11 , wherein the electric field is applied at a voltage ranging from 120 kV to 150 kV.