Loopseal Heat Exchanger Segmentation for Compact Fluidized Bed Boiler

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Solution Overview

Problem

Existing loopseal heat exchangers in circulating fluidized bed boilers face challenges in accurately controlling heat exchange due to limited space for heat exchangers as particle separators shrink, requiring efficient heat recovery while maintaining controllability and allowing for human access during manufacturing.

Innovation Solution

A heat exchanger design with first and second heat exchanger tubes, where bed material flows through separate feeding chambers to control heat exchange, with nozzles for fluidizing air to manage bed material distribution between the tubes, allowing for independent control and efficient heat recovery in a compact, accessible layout.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the particle separator size is reduced to meet decentralized boiler unit demands, then the overall heat exchanger space is reduced, but the chambers become too small for human access during manufacturing

Engineering Contradiction:

Improveheat exchanger volumeVSAvoidmanufacturability

Core Design Contradiction:

Volume of moving objectVSEase of manufacture

Solution Approach 1:

The heat exchanger is divided into multiple separate chambers (first chamber with first heat exchanger tubes, second chamber with second heat exchanger tubes) that can be accessed independently. This segmentation allows workers to access and work in each chamber without needing to enter a large single space, thus maintaining manufacturability even when the overall heat exchanger volume is reduced for decentralized applications.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If two separate feeding chambers are arranged side-by-side to feed bed material to separate heat exchange chambers, then control of heat exchange is improved, but the overall size of the heat exchanger increases

Engineering Contradiction:

Improveheat exchange controlVSAvoidheat exchanger area

Core Design Contradiction:

Ease of operationVSArea of stationary object

Solution Approach 1:

Instead of arranging the two feeding chambers side-by-side in a horizontal layout, the patent positions them vertically stacked (first feeding chamber above second feeding chamber). This dimensional change allows both chambers to be accessed and controlled independently for optimized heat exchange, while significantly reducing the horizontal footprint and overall area occupied by the heat exchanger system.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If the heat exchanger chambers are made large enough for human access during manufacturing, then ease of manufacture is improved, but the overall size of the heat exchanger increases

Engineering Contradiction:

ImprovemanufacturabilityVSAvoidheat exchanger volume

Core Design Contradiction:

Ease of manufactureVSVolume of moving object

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

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 enables precise control of heat transfer and efficient heat recovery from bed material to steam, accommodating smaller spaces while allowing for human access during manufacturing, enhancing operational efficiency and flexibility.

Implementation Method 1

heat exchange from the bed material to the circulating steam

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

heat exchange chamber provided with heat transfer tubes

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 3

nozzles for fluidizing air to manage bed material distribution

Methodology Applied

Scientific EffectFluidization: Fluidisation

Data Source

PatentEP4071407B1A heat exchanger for a loopseal of a circulating fluidized bed boiler and a circulating fluidized bed boiler

Publication Date: 2024.03.20 VALMET TECH OY

Figure 1
Figure 2
Figure 3~4a

AI summary

A heat exchanger (10) suitable for recovering heat from bed material of a fluidized bed boiler (1). The heat exchanger (10) comprises first and second heat exchanger tubes (810, 820) and first and second feeding chambers (310, 320) configured to supply bed material to the first and second heat exchanger tubes (810, 820), respectively. The first heat exchanger tubes (810) are arranged on a first side of a plane (P) that intersects the first feeding chamber (310) and the second heat exchanger tubes (820) are arranged on a second side of the plane (P). The first feeding chamber (310) is configured to supply bed material to the second feeding chamber (320).