Liquid purification or separation – Processes – Including controlling process in response to a sensed condition
Patent
1993-03-16
1996-04-16
Drodge, Joseph W.
Liquid purification or separation
Processes
Including controlling process in response to a sensed condition
2105122, 210739, 210788, 210805, B01D 17038
Patent
active
055079555
DESCRIPTION:
BRIEF SUMMARY
Hydrocyclones are used for de-oiling the water which is separated from production fluids on offshore oil platforms or other production facilities.
A plurality of hydrocylcones are required to cater for the maximum flow rate of water produced from sources and these are commonly grouped in banks, often with the different banks within different pressure vessels. Each individual hydrocyclone has a particular inlet flow rate range over which it efficiently separates oil from water and it is important that none of the hydrocyclones are operated in a manner such that the inlet flow rate falls below a minimum value. The flow rate of production fluids can vary appreciably, for example, the production of water can be comparatively low with a young field or upon start up after stoppage. Consequently, means have had to be provided for shutting off different hydrocyclones or banks of hydrocyclones using conventional valve means, and it is desirable that operations personnel be spared the labour-intensive task of switching on and off the various hydrocyclones upon a change in the flow rate of water to be de-oiled.
In accordance with the present invention, in a method of operating a system for de-oiling water, utilising hydrocyclone separators each having a mixture inlet, an overflow oil outlet and an underflow water outlet, the flow through at least one hydrocyclone is sensed, and if the flow approaches a threshold below which there is insufficient flow through the respective hydrocyclone(s) for satisfactory operation, an additional supply of water is fed to the mixture inlet(s) to maintain the flow safely above the threshold.
The invention is conveniently applied to a plurality of banks of the hydrocyclones, each bank acting in parallel having mixture inlet means leading to the mixture inlets of the hydrocyclones of the respective bank, an outlet means leading from the overflow oil outlets of the hydrocyclones of the respective bank, and water outlet means leading from the underflow water outlets of the hydrocyclones of the respective bank, wherein the flow through the bank of hydrocyclones is sensed and the additional supply of water is fed to the mixture inlet means to maintain the flow safely above the threshold through the hydrocyclones of the respective bank. Each of the banks may be mounted in a respective pressure vessel.
With this arrangement, it is unnecessary to shut down any hydrocyclones upon a reduction in the flow rate of water to be de-oiled, the hydrocyclones being maintained with a sufficient inlet flow for efficient operation by the automatic supply of additional water to the mixture inlets.
The sensing may be carried out indirectly by a differential pressure controller which effectively senses the pressure difference between the mixture inlet and underflow water outlets of the individual hydrocyclones, although in practice by sensing the pressure difference between the mixture inlet means and the water outlet means of a pressure vessel. These pressure differentials represent in a particular case the underflow rate of purified water. Alternatively, the flow rate could be measured more directly by means of a flow meter which senses either the mixture inlet flow rate or the underflow outlet flow rate.
The additional water may be from any source, such as adjacent sea water, but is conveniently water that has already been purified by the hydrocyclones and obtained, for example, from a degassing vessel which is used to deaerate the purified water downstream of the hydrocyclones.
An example of a system constucted to operate in accordance with the present invention is illustrated diagrammatically in the accompanying drawing.
As shown, a mixture of gas, oil and water flows from wells 1 into a manifold 2 and is discharged into a three phase separator 3 where partial separation of oil, gas, and water occurs by gravitational settlement. It is usual that the pressure within the three phase separator 3 is controlled by controlling the rate at which gas is expelled from the three phase separator. This is achieved b
REFERENCES:
patent: 4544486 (1985-10-01), Carroll
patent: 4622150 (1986-11-01), Carroll
patent: 4659461 (1987-04-01), Carroll
patent: 4737287 (1988-04-01), Predergast
patent: 4822484 (1989-04-01), Prendergast et al.
patent: 4844812 (1989-07-01), Haynes et al.
patent: 4844817 (1989-07-01), Flanigan et al.
patent: 5055202 (1991-10-01), Carroll et al.
OTC Publ. 5594-Hydrocyclones: A Solution to Produced Water Treatment, 1987.
Maschinenkunde fuur Muller (Machine Science for Millers) 1986.
Drodge Joseph W.
Merpro Montassa Limited
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