Bulged Inlet Diffuser for Heat Recovery Boiler Misalignment

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Solution Overview

Problem

Misalignment between hot flue-gases sources and heat recovery boiler inlets leads to inefficient heat exchange, temperature inconsistencies, and increased risk of boiler damage and pollution due to non-homogeneous gas flow, especially when combined with afterburners.

Innovation Solution

A heat recovery boiler design featuring an inlet diffuser with bulges that increase and then decrease the passage section, creating a mixing zone to uniformize flue gas flow speed and temperature, allowing for efficient coupling regardless of alignment and reducing the risk of cracks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the heat recovery boiler is connected to the hot flue-gases source in a non-linear configuration, then the installation flexibility is improved, but the heat exchange efficiency deteriorates and temperature uniformity worsens

Engineering Contradiction:
Improveinstallation flexibilityVSAvoidheat exchange efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The inlet diffuser is divided into multiple sections with varying passage areas, creating a segmented flow path that progressively mixes and uniformizes the flue gas flow, allowing non-linear installation while maintaining heat exchange efficiency

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The passage section of the inlet diffuser is varied locally along the flow direction, with different areas at different positions to create optimal flow conditions for mixing and temperature uniformity, enabling flexible installation configurations

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the hot flue-gases source is not aligned with the inlet of the heat recovery boiler, then the installation flexibility is improved, but the temperature uniformity of flue gases deteriorates

Engineering Contradiction:
Improvecoupling flexibilityVSAvoidtemperature uniformity
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The inlet diffuser passage is segmented into zones with different cross-sectional areas, creating multiple flow regions that promote mixing and temperature uniformity even when the flue-gases source is misaligned with the boiler inlet

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The passage section parameter of the inlet diffuser is changed along the flow direction to optimize flow patterns, creating conditions that achieve temperature uniformity regardless of alignment between the flue-gases source and boiler inlet

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the flue gas flow is non-homogeneous, then the installation simplicity is maintained, but the risk of boiler crackage increases

Engineering Contradiction:
Improveinstallation simplicityVSAvoidboiler reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The inlet diffuser is designed with segmented passage sections that create controlled flow patterns, promoting homogeneous temperature distribution and reducing thermal stresses that could cause cracking, while maintaining simple installation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The passage section is varied locally to create optimal flow conditions that uniformize temperature distribution, reducing thermal gradients and the risk of crackage without complicating the installation process

Inventive Principle:
Principle #3Local quality

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

The bulged inlet diffuser ensures uniform flue gas flow, enhancing boiler efficiency and reliability, reducing the risk of damage, and stabilizing flame and emissions, while eliminating the need for complex homogenization systems.

Implementation Method 1

The presence of the bulge in the inlet diffuser allows the creation therein of at least one mixing zone capable of making the flow of flue gases flowing in the inlet diffuser uniform, in terms of speed and temperature

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 2

a steam circuit fed with water and extending at least in part inside the flue-gases flowing chamber so as to exploit the heat of the flue-gases to generate steam

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentEP3828464B1Heat recovery boiler and plant comprising said heat recovery boiler
Publication Date: 2024.02.14 AC BOILERS SPA
  • EP3828464B1 patent drawingFigure 1
  • EP3828464B1 patent drawingFigure 2~3

AI summary

A heat recovery boiler is provided with: a flue-gases flowing chamber (11) extending along a longitudinal axis (A) and provided with an inlet (16) and an outlet (17); a steam circuit (14) fed with water and extending at least in part inside the flue-gases flowing chamber (11) so as to exploit the heat of the flue-gases to generate steam; an inlet diffuser (12) connected to the inlet (16) of the flue-gases flowing chamber (11) wherein flue-gases from a flue-gases source (9) flow in one advancing direction (D); at least one first wall (22; 19; 20) of the inlet diffuser (12) being provided with at least one first bulge (30).