Boiler Separator Element for Superheater Corrosion Protection

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Solution Overview

Problem

Existing boilers incinerating refuse face inefficiencies in energy transfer from flue gases to steam due to lack of direct contact and corrosion issues with corrosive gases, leading to reduced power output and shortened lifespan of superheaters.

Innovation Solution

A boiler design that separates flue gases into less-corrosive and corrosive streams using a movable separator element, such as a plate or pipe with nozzles, to protect the end superheater from corrosive gases, allowing for direct contact of less-corrosive gases with the superheater and enhancing energy transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the end superheater is placed in direct contact with flue gases for efficient heat transfer, then the energy transfer efficiency is improved, but the superheater is exposed to corrosive gases which reduces its lifespan

Engineering Contradiction:
Improveenergy transfer efficiencyVSAvoidsuperheater lifespan
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The flue gas flow is segmented into two separate streams using a separator element: a first stream containing corrosive components (HCl, HF, SO3, metals) and a second stream with fewer corrosive components. The end superheater is positioned to receive primarily the second, less-corrosive stream, thereby reducing corrosion while maintaining heat transfer efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A separator element acts as an intermediary structure that divides the flue gas flow into corrosive and less-corrosive streams. This mediator allows the system to maintain direct contact between flue gases and the end superheater for efficient heat transfer while protecting the superheater from the full corrosive impact by routing it through the less-corrosive stream.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If the superheater operates at higher temperatures for increased power output, then the electrical power output is improved, but the corrosion from flue gases accelerates and shortens superheater lifespan

Engineering Contradiction:
Improveelectrical power outputVSAvoidcorrosion damage
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

Different regions of the flue gas flow are assigned different qualities based on their corrosive content. The separator element creates a local environment with reduced corrosive components around the end superheater, allowing it to operate at higher temperatures for increased power output without suffering accelerated corrosion from the full-strength corrosive flue gas mixture.

Inventive Principle:
Principle #3Local quality

3Reliability

If a separator element is introduced to protect the superheater from corrosive gases, then the superheater lifespan is extended, but the device complexity increases

Engineering Contradiction:
Improvesuperheater lifespanVSAvoidboiler structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The separator element is designed to be movable rather than fixed, capable of adjusting its position to optimize the separation of corrosive and less-corrosive gas streams. This dynamic adjustment allows the system to adapt to varying operating conditions and maintain effective protection of the end superheater while managing structural complexity through a single adjustable component rather than multiple fixed structures.

Inventive Principle:
Principle #15Dynamics

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 increases the lifespan of the end superheater and achieves a high and efficient electrical power output by maintaining the superheater in a less-corrosive environment, optimizing steam temperature and power generation.

Implementation Method 1

a separator element adapted to separate the flue gases into the less-corrosive gas flow and the corrosive gas flow

Methodology Applied
Scientific EffectGas separation:

Implementation Method 2

the end superheater is located in the flow of the less-corrosive gas... the end superheater, where some means are provided to extend the lifespan of the end superheater

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

the steam, when fed in a steam turbine driving a generator, provides a high and efficient power output

Methodology Applied
Scientific EffectThermal energy conversion:

Implementation Method 4

a steam turbine driving a generator, provides a high and efficient power output

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP1934525B8A boiler producing steam from flue gases under optimised conditions
Publication Date: 2019.03.06 BABCOCK & WILCOX VOELUND AS

AI summary

This invention relates to a boiler (1) drying, igniting and combusting refuse and producing steam (2, 2a) by heat exchange with flue gases (3), said boiler defining a main flow direction (5) of gases, said boiler (1) comprising a separator element (4) and an end superheater (8), the separator element (4) being adapted for separating said flue gases (3) into streams of a less-corrosive gas flow (6) and a corrosive gas flow (7), said separator element (4) being located substantially in and along said main flow direction (5), said end superheater (8) being located in proximity to said separator element (4) and in the flow (6) of said less-corrosive gas. Said separator element (4) comprises a plate (4a) or a wall (4b), which in a number of said separator elements (4) forms a channel as another separator element. This provides for an increased lifetime of said superheater and makes the boiler provide a high and efficient electrical power output.