Oil-water separator

Abstract

The oil-water separator is installed in a substantially horizontal crude oil pipeline for separating water from the oil and water mix. The separator includes a depending vortex and settling chamber depending from the pipeline, the segment of the pipeline and the separator defining a generally T-shaped configuration. Oil and water flowing through the pipeline drop into the chamber as it flows through the pipeline and over the chamber. The denser water tends to settle into the bottom of the chamber, while the lighter oil is entrained back into the flow through the pipeline. A sensor detects water collected in the bottom of the chamber and provides a signal to open a drain valve when sufficient water has been collected. While only a single separator serves to collect a substantial fraction of water, a series of separators may be installed along the pipe to remove more water from the oil.

We claim: 
     
         1 . An oil-water separator, comprising:
 a pipeline having an input end and an output end coaxial with the input end, the pipeline defining a rectilinear fluid flow path;   a cylindrical water separation chamber branching off the pipeline normal thereto, the water separation chamber having an interior, a first end opening into the pipeline, defining an open mouth of the chamber, and an opposing second bottom end;   a drain valve mounted at the bottom end of the chamber, the drain valve having an open position permitting a fluid to drain out of the separation chamber, and a closed position closing the second end of the separation chamber;   an oil-water fraction sensor communicating with the interior of the water separation chamber, the sensor generating a signal corresponding to the fractions of oil and water in the fluid in the water separation chamber; and   a drain valve controller connected to the drain valve and the oil-water fraction sensor, the controller controlling the drain valve to move to the open position when the signal from the sensor corresponds to a level below a threshold fraction of oil in the fluid, and to move to the closed position when the signal from the sensor corresponds to a level above a threshold fraction of oil in the fluid;   wherein the oil-water separator is adapted for installation with the pipeline extending horizontally and the water separation chamber extending downward from the pipeline, whereby a mixture of oil and water flowing through the pipeline forms a vortex at the open mouth of the water separation chamber, the oil and water separating in the chamber, the water falling into the water separation chamber towards the drain valve and the oil rising out of the water separation chamber to flow in the pipeline.   
     
     
         2 . The oil-water separator as recited in  claim 1 , wherein the separation chamber has a width and a depth, the depth being at least twice the width. 
     
     
         3 . A multi-stage oil-water separator, comprising a plurality of the oil-water separators according to  claim 1 , the oil-water separators being spaced apart in the pipeline for providing multiple successive stages of oil-water separation. 
     
     
         4 . The oil-water separator according to  claim 1 , wherein said pipeline and said water separation chamber comprise an integrated Tee connector unit adapted for mounting in an oil transport and delivery line. 
     
     
         5 . The oil-water separator according to  claim 1 , further comprising a gas separator for separating gas from two-phase oil-gas fluid flows and three-phase oil-water-gas fluid flows, the gas separator having:
 a cylindrical gas separation chamber branching off the pipeline normal thereto spaced apart from and following said water separation chamber in the fluid flow path, the gas separation chamber being inverted and extending from the pipeline in a direction 180° opposite said water separation chamber, the gas separation chamber having an interior, a first end opening into the pipeline, defining an open mouth of the gas separation chamber, and an opposing second end closing the gas separation chamber;   a gas drain valve mounted at the second end of the chamber, the gas drain valve having an open position permitting a fluid to drain out of the gas separation chamber, and a closed position closing the second end of the gas separation chamber;   a multi-phase flow sensor communicating with the interior of the gas separation chamber, the sensor generating a signal corresponding to the fractions of oil and gas in the fluid in the gas separation chamber; and   a drain valve controller connected to the gas drain valve and the multi-phase flow sensor, the controller controlling the gas drain valve to move to the open position when the signal from the sensor corresponds to a level above a threshold fraction of gas separated from the fluid, and to move to the closed position when the signal from the sensor corresponds to a level below a threshold fraction of gas in the gas separation chamber;   wherein the oil-water separator is adapted for installation with the pipeline extending horizontally and the water separation chamber extending downward from the pipeline, followed by the gas separation chamber extending upward from the pipeline;   whereby a mixture of oil, water, and gas flowing through the pipeline forms a vortex at the open mouth of the water separation chamber, the water separating from the mixture in the water separation chamber, the water falling into the water separation chamber towards the drain valve and the oil-gas mixture rising out of the chamber to flow in the pipeline; and   whereby the oil-gas mixture flowing through the pipeline forms a vortex at the open mouth of the gas separation chamber, the gas separating from the mixture in the gas separation chamber, the gas rising into the gas separation chamber towards the gas drain valve and the remaining fluid from the mixture continuing to flow in the pipeline.   
     
     
         6 . A multi-stage oil-water separator, comprising a plurality of the oil-water separators according to  claim 5 , said water separator chambers and said gas separator chambers being spaced apart and alternating in the pipeline for providing multiple alternating successive stages of oil-water and oil-gas separation. 
     
     
         7 . The oil-water separator according to  claim 5 , wherein said pipeline, said water separation chamber, and said inverted gas separation chamber comprise an integrated unit adapted for mounting in an oil transport and delivery line.