Once-through steam generator
AssigneeShell California Production Inc.
InventorsArthur W. Nelson, James H. Ragland
Life of this patent
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Abstract
An evaporator for producing wet steam in a cogeneration plant wherein the evaporator is a multiple pass unit having continuous in-tube flow paths from inlet to outlet. The evaporator is a shell and tube type with the clean steam on the shell side and water in the tubes. The evaporator is particularly useful in a cogeneration plant used in a secondary recovery process using contaminated wet steam.
Claims8
A method for producing low quality steam containing dissolved solids for use in the thermal recovery of crude oil, said method comprising:
- generating high pressure, high quality steam;
- partially expanding and reducing the pressure and temperature of the high quality steam in a steam turbine;
- exhausting the steam from the steam turbine into the shell side of a shell and tube heat exchanger;
- and
- introducing the water containing the dissolved solids into the tubes of the heat exchanger through an inlet while maintaining a continuous in-tube flow path, the cross-section of said flow path increasing in size from the inlet to the outlet, and the flow rate of the water/steam mixture through the tubes being sufficiently high to maintain the solids dissolved in the liquid phase and the tubes substantially clean and removing the low quality steam containing dissolved solids through the outlet of the heat exchanger.
An apparatus for producing low quality steam containing dissolved solids for use in the thermal recovery of crude oil, said apparatus comprising:
- a steam generator for producing high quality, high pressure superheated steam;
- a steam turbine, said steam generator being coupled to said turbine;
- and
- a shell and tube heat exchanger, at least a portion of the steam supplied to said turbine being supplied to the shell side of said heat exchanger and said solid-containing water being introduced in the tube side of said heat exchanger, said heat exchanger having a continuous in-tube flow path from inlet to outlet for each tube of the heat exchanger, the cross-sectional area of said flow path increasing between the inlet and outlet.
Dependencies are inferred from the claim text.