Use of single-lead and multi-lead ribbed tubing for sliding pressure once-through boilers
AssigneeThe Babcock & Wilcox Company
InventorMelvin J. Albrecht
Life of this patent
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Abstract
A vertical tube, once-through, sliding pressure steam generator comprises a furnace having an outlet and heat exchanger surfaces made of smooth bore tubes, single-lead ribbed (SLR) tubes, and multiple-lead ribbed (MLR) tubes. All of these tubes are preferably constructed as membrane wall tube panels. The steam generator includes fuel burners for burning fuel and air within the housing, creating low, medium and high heat flux regions within the furnace. Fluid flows through the tubes of the wall panels to provide an efficient heat exchanger. The smooth bore tubes are located at the low heat flux regions, and the SLR and/or MLR tubes are located in the high and medium heat flux regions.
Claims20
A once-through steam generator suitable for sliding pressure operation over a wide load range and especially at low loads, the steam generator having a furnace partially defined by fluid-cooled enclosure walls, comprising:
- fuel burner means for burning fuel and air in a combustion process which creates a vertical variation in heat flux rates on the enclosure walls including one or more low and one or more high heat flux regions;
- and
- wherein the fluid-cooled enclosure walls surrounding the one or more low heat flux regions of the furnace incorporate smooth bore tubes, and the fluid-cooled enclosure walls surrounding the one or more high heat flux regions incorporate both single-lead ribbed (SLR) tubes and multiple-lead ribbed (MLR) tubes to avoid departure from nucleate boiling (DNB) and critical heat flux (CHF) conditions in the one or more high heat flux regions.
In a once-through, vertical tube steam generator having a furnace partially defined by fluid-cooled enclosure walls, an arrangement of fluid-conveying tubes forming the enclosure walls comprising:
- smooth bore tubes forming the fluid-cooled walls surrounding a lower portion of the furnace;
- multiple-lead ribbed (MLR) tubes forming the fluid-cooled walls surrounding a first intermediate portion of the furnace located directly and vertically above the lower portion;
- single-lead ribbed (SLR) tubes forming the fluid-cooled walls surrounding a second intermediate portion of the furnace located directly and vertically above the first intermediate portion;
- and
- smooth bore tubes forming the fluid-cooled walls surrounding an upper portion of the furnace located directly and vertically above the second intermediate portion, the tubes in each portion of the furnace being fluidically connected to one another.
In a once-through, spiral tube steam generator having a furnace partially defined by fluid-cooled enclosure walls, an arrangement of fluid-conveying tubes forming the enclosure walls comprising:
- smooth bore tubes forming the fluid-cooled walls surrounding a lower portion of the furnace;
- multiple-lead ribbed (MLR) Tubes forming the fluid-cooled walls surrounding a first intermediate portion of the furnace located directly and vertically above the lower portion;
- single-lead ribbed (SLR) tubes forming the fluid-cooled walls surrounding a second intermediate portion of the furnace located directly and vertically above the first intermediate portion;
- and
- smooth bore tubes forming the fluid-cooled walls surrounding an upper portion of the furnace located directly and vertically above the second intermediate portion, the tubes in each portion of the furnace being fluidically connected to one another.
Dependencies are inferred from the claim text.