STEAM GENERATOR ARRANGEMENT
First Claim
1. In a boiler flue of a boiler for producing a flowing flue gas, the boiler flue having a plurality of tube banks having and a tube bank inlet and a tube bank outlet within parallel gas flow paths within the boiler setting, gas flow through each of the parallel gas flow paths controlled by individual outlet flow control dampers, an internal gas bypass arrangement, comprising:
- one or more bypass flues in fluid communication with the boiler flue and disposed through or around at least one tube bank within a flow controlled gas path for directing flue gas from the tube bank inlet through or around the tube bank to the tube bank outlet, and wherein the one or more bypass flues are fully contained within the parallel gas flow paths within the boiler setting.
14 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus effectively bypasses flue gas through or around selected boiler convection heat transfer tube banks within a new or existing boiler flue. Heat transfer tubes are removed, or omitted in the design of a new boiler flue, forming one or more voids at one or more locations within the tube banks. A bypass flue or conduit is formed within each void, for example using steel plates, along with existing flue walls, or using an integral sleeve. A wall of the bypass flue may include water or steam-cooled tubes. Dampers may be installed at either end of or within the bypass flue to control the amount of flue gas directed through each bypass flue.
24 Citations
16 Claims
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1. In a boiler flue of a boiler for producing a flowing flue gas, the boiler flue having a plurality of tube banks having and a tube bank inlet and a tube bank outlet within parallel gas flow paths within the boiler setting, gas flow through each of the parallel gas flow paths controlled by individual outlet flow control dampers, an internal gas bypass arrangement, comprising:
one or more bypass flues in fluid communication with the boiler flue and disposed through or around at least one tube bank within a flow controlled gas path for directing flue gas from the tube bank inlet through or around the tube bank to the tube bank outlet, and wherein the one or more bypass flues are fully contained within the parallel gas flow paths within the boiler setting. - View Dependent Claims (2, 3, 4, 5)
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6. A method of controlling flue gas flowing through a boiler flue having parallel gas flow paths, superheater surface located in one gas flow path and reheater surface located in another gas flow path and outlet flow control dampers provided in the superheater and reheater gas flow paths, and within the boiler setting of a boiler, the boiler flue having a plurality of tube banks and a tube bank inlet and a tube bank outlet within the parallel gas flow paths, and an internal gas bypass arrangement fully contained within the boiler setting including one or more bypass flues in fluid communication with the boiler flue and disposed through or around at least one tube bank for directing flue gas from the tube bank inlet to the tube bank outlet, the one or more bypass flues each having a control damper located at one of either end of or within the bypass flue, comprising the steps of:
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modulating the outlet flow control dampers in the superheater and reheater gas flow paths to control relative amounts of flue gas flowing therethrough to maintain at least one of superheater and reheater steam temperatures at desired values; and simultaneously modulating the control dampers in the one or more bypass flues to control the amount of flue gas flowing across the at least one tube bank to maintain a temperature of the flue gas exiting from the boiler flue at a desired value over a desired operating load range of the boiler. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A method of modifying a boiler flue of a boiler to provide an internal gas bypass arrangement, the boiler flue having parallel flow gas paths with superheater surface located in one gas flow path, reheater surface located in another gas flow path and outlet flow control dampers provided in the superheater and reheater gas flow paths, the boiler flue having a plurality of tube banks having multiple tube bank inlets and multiple tube bank outlets within the parallel gas flow paths within the boiler setting, comprising the steps of:
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removing tubes from at least one of the tube banks to create a void within the tube bank; installing a bypass flue within the boiler setting in the void from the inlet of the tube bank to the outlet of the tube bank for transporting flue gas there through; and installing a damper within the bypass flue for controlling a pre-selected portion of the flowing flue gas through the bypass flue. - View Dependent Claims (13, 14, 15, 16)
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Specification