Steam generator having a high pressure combustor with controlled thermal and mechanical stresses and utilizing pyrophoric ignition

• US 4,648,835 A
• Filed: 07/08/1985
• Issued: 03/10/1987
• Est. Priority Date: 04/29/1983
• Status: Expired due to Fees

• Current Assignee: Texsteam, Inc. (Healthier Choices Management Corp.)
• Original Assignee: Enhanced Energy Systems
• Inventors: Mulac, Anthony J., Donaldson, A. Burl, Fox, Ronald L., Eisenhawer, Stephen
• Primary Examiner(s): Scott, Samuel
• Assistant Examiner(s): KAMEN, NOAH P
• Application Number:
  US06/753,800
• Time in Patent Office: 610 Days
• Field of Search: 431/4, 431/6, 431/158, 431/190, 431/242, 431/243, 431/267, 431/353, 431/354, 431/114, 60/39.55, 60/39.53, 60/39.05, 166/59, 166/260, 166/302, 239/419.5, 239/424.5, 239/427, 261/16, 261/18 A, 261/117
• US Class Current: 431/4
• CPC Class Codes: E21B 36/02 using burners
• CPC Class Codes: F22B 1/26 Steam boilers of submerged-flame type, i.e. the flame being surrounded by, or impinging on, the water to be vaporised , e.g. water in sprays
• CPC Class Codes: F23D 14/34 Burners specially adapted for use with means for pressurising the gaseous fuel or the combustion air
• CPC Class Codes: F23L 7/002 Supplying water

Abstract

A steam generator having substantial thermal capacity for producing high quality steam used primarily for downhole steam generation in tertiary oil recovery. Incorporated in the generator is a novel high pressure, high heat release combustor, utilizing high pressure gaseous fuel and compressed gas oxidizer such as air, wherein thermal and mechanical stresses on the combustor structure are controlled. A method for controlling combustion induced mechanical stresses on the combustor through fluid injection is also disclosed. Disclosed designs provide substantially increased combustor life in "Downhole" Steam Generation service. The burner employs an ignition technique utilizing gaseous injection of a pyrophoric compound such as triethylborane (TEB).

Claims

1. In a direct fired high pressure steam generator of the type having a burner base with means for supplying feedwater, gaseous fuel and oxidizer, and a feedwater cooled combustion chamber extending from said base along a common longitudinal axis, said base/chamber extension defining a chamber inlet end, said chamber generating high pressure combustion gases and having a section for generating steam by mixing feedwater and combustion gas, the improvement comprising;

a plurality of conduits in said base terminated by inlet ports defined by said inlet end, said conduits angularly disposed to said longitudinal axis of said base and chamber for directing gaseous oxidizer through said ports internal of said combustion chamber and in said base end for generating gaseous oxidizer jets, said jets intersecting entirely internal said chamber; and

,

a central fuel inlet port in said base and centrally adjacent said oxidant inlet ports for generating a central fuel jet, said jet intersecting said oxidizer jets and means for introducing water into said fuel inlet port so as to reduce vibrations caused by combustion.

2. The generator of claim 1 where said angular disposition has a range of 15°

-45°

.

3. Apparatus for downhole generation of steam and high temperature gases of the type having a water cooled combustion chamber and steam generating sections comprising;

a burner base with means for introducing gaseous fuel, oxidizer, and water, said base having supply and combustion ends and a central axis;

a plurality of oxidizer conduits in said base, said conduits angularly disposed about said base axis, having initial and terminal ends in said base supply and combustion ends respectively, said terminal ends defining oxidizer inlet ports in said base combustion end;

a fuel inlet passage in said base, communicating said supply and combustion ends, said base combustion end and fuel passage defining a fuel inlet port in said base combustion end, said port essentially coaxial said base axis;

a generally cylindrical open ended combustion chamber extending from and coaxial of said base combustion end, and surrounding said oxidizer and fuel inlet ports for containing fuel and oxidizer during combustion and further directing combustion gas flows through said open end;

a generally cylindrical open ended conduit extending from said base combustion end, said conduit telescoping said chamber and extending beyond said chamber open end, said extension defining a steam generator section downstream said chamber open end, said telescoped chamber outer surface and conduit inner surface further defining an open ended first flow passage for cooling said chamber and supplying water to said generator for producing steam;

an outer housing extending from and generally coaxial of said base combustion end, and partially surrounding said conduit, said housing inner surface and conduit outer surface defining a second flow passage in fluid communication with said first passage adjacent said base combustion end;

means in said second flow passage for admitting feedwater at a predetermined rate;

means admitting pressurized gaseous fuel and oxidizer at pressures in a range of 500 to 2000 pounds per square inch and in predetermined flow rate ratios to said feedwater rate to said base supply end;

means in said combustion chamber, for igniting fuel and air mixture;

wherein said base conduits and inlet ports angularly inject oxidizer and fuel flows for combustion within said combustion chamber, thereby generating high temperature gases, said gases exiting said chamber open end; and

feedwater exiting said first passage open end generate high pressure steam through contact with said high temperature gases and means for introducing water into said fuel inlet port so as to reduce vibrations caused by combustion.

4. The apparatus of claim 3 wherein the axis of said oxidizer conduits and the base cylindrical axis are in a range of 10-45 degrees.

5. The apparatus of claim 4 wherein the burner further comprises three symmetrically spaced oxidizer inlet ports.

6. The apparatus of claim 27 wherein said introduced water is injected at a rate of 0.3 to 0.6 percent of the feedwater flow rate.

7. A method of improving the service life of a direct fired downhole steam generator, said generator having base means supplying gaseous fuel, water and oxidizer to said base, an outer cylinder and combustion chamber extending from said base, said cylinder surrounding and extending beyond said combustion chamber, said extension defining a steam generating section;

and,

conduit means in said base said conduit means supplying said gaseous fuel and oxidizer to said combustion chamber and feedwater to said steam generator, comprising the steps of;

supplying gaseous fuel pressurized in the range of 500 to 2000 pounds per square inch to said fuel conduit means;

supplying a gaseous oxidizer pressurized to the range of 500 to 2000 pounds per square inch;

supplying feedwater to said feedwater conduit means at pressures in the 500 to 2000 pounds per square inch range, and at a predetermined flow rate;

mixing said fuel and water through injecting water into said fuel conduit means, said water having a predetermined flow rate;

wherein ultrasonic pulsations generated by the combustion process are controlled.

8. The method of claim 9 further including the step of controlling said injected water flow rate to the range of 0.3 to 0.6% of said feedwater rate.