Simplified Boiler Water Cycle for Fluidized Bed Reactors
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Solution Overview
Problem
The complexity of boiler water cycles in large fluidized bed boilers, particularly in supercritical circulating fluidized bed boilers, is exacerbated by numerous inlet ducts, which complicates the arrangement of the wind box and increases costs due to the need for multiple inlet headers and supporting structures.
Innovation Solution
A simplified boiler water cycle design featuring horizontal inlet headers of sufficient diameter, each connected to a single drop leg, with water tubes extending directly to these headers and optional grid chambers within the wind box, reducing the number of inlet ducts and supporting structures while ensuring uniform water distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple inlet headers and numerous inlet ducts are used to ensure uniform water distribution in large boilers, then water distribution uniformity is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges multiple inlet headers into a single inlet header that serves all water tubes around the furnace perimeter. This single inlet header receives water from one drop leg and distributes it uniformly to all water tubes, eliminating the need for multiple inlet headers and numerous inlet ducts while maintaining water distribution uniformity.
Solution Approach 2:
The single inlet header performs the function of multiple inlet headers by being connected to multiple inlet ducts that serve different sections of the furnace. This universal inlet header structure reduces the number of components while maintaining the ability to distribute water uniformly across all water tubes.
2Ease of operation
If numerous inlet ducts are installed to connect drop legs to inlet headers, then water flow distribution is improved, but the arrangement of wind box and supporting structures becomes more complex
Solution Approach 1:
The patent combines multiple inlet duct connections into a single inlet header system. Instead of having multiple separate inlet ducts connecting different drop legs to different inlet headers, the design uses one inlet header with multiple inlet ducts branching from it, simplifying the overall arrangement and reducing supporting structure requirements.
3Manufacturing precision
If multiple inlet headers are used in large boilers, then water distribution to all tubes is improved, but cost increases due to additional supporting structures
Solution Approach 1:
The patent reduces the number of inlet headers from multiple to just one, which significantly reduces manufacturing costs. The single inlet header is connected to multiple inlet ducts that distribute water to all water tubes, eliminating the need for multiple expensive inlet headers and their associated supporting structures while maintaining comprehensive water distribution coverage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design simplifies the boiler water cycle, allows for homogeneous air distribution, and reduces the need for additional supporting structures, while maintaining sufficient water flow and power output in large boilers like those with 400 MW capacity.
Implementation Method 1
a drop leg (26) and a number of inlet ducts (28), each inlet duct (28) being connected to an end of one of said inlet headers (30) merely by means of an inlet duct (28) connected to the end of said inlet header (30)
Implementation Method 2
The water to be evaporated is mostly led either from the steam drum of a drum boiler or from the preheating surfaces for water in a once-through utility boiler to the lower part of the boiler
Implementation Method 3
Water tubes in the water tube panels of the outer walls of the furnace in turn are connected to the inlet headers to heat up and evaporate water in the water tubes
Data Source
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AI summary
Boiler water cycle of a fluidized bed boiler (10) and a fluidized bed boiler (10), preferably a supercritical once-through-unit (OTU) boiler with a boiler water cycle, comprising a drop leg (26) and a number of horizontal inlet headers (30), substantially of the length of the front wall (14) of the boiler furnace (12), arranged below the furnace (12) of the fluidized bed boiler (10), the inner diameter of the inlet headers (30) being preferably at least 200 mm, whereby the extensions (44, 46) of the water tubes in the front wall (14) and the rear wall (38) of the furnace (12) are connected directly to said inlet headers (30) and each of the inlet headers (30) is in flow communication with the drop leg (26) only through an inlet duct (28) connected to the end of the inlet header (30). The inlet headers (30) preferably comprise a front wall chamber (48) and a rear wall chamber(50) arranged below the front wall (14) and the rear wall (38) of the furnaσe(12), respectively, and a grid chamber (52, 54) arranged below the mid-portion of the grid, preferably inside a wind box (20), whereby preferably a first portion of the extensions (44,46) of the water tubes of the front wall (14) and the rear wall (38) are connected directly to the front wall chamber (48) and the rear wall chamber (50), respectively, and a second portion of the water tubes of the front wall (14) and the rear wall (38) extend as grid tubes (42) parallel to the furnace (12) grid, and are connected to the grid chamber (52, 54).