Fluidized Bed Ilmenite Recycling via Mechanical and Magnetic Separation

Solution Overview

Problem

The existing processes for fluidized bed boilers fail to effectively recycle and reuse ilmenite bed material, leading to unnecessary consumption of this natural resource and inefficiencies in combustion processes due to the deterioration of ilmenite particles' oxygen-carrying capacity and mechanical strength over time.

Innovation Solution

A system comprising a bottom ash removal device, mechanical classifier with a mesh size of 200 to 1,000 μm, and a magnetic separator to separate and recirculate ilmenite particles, maintaining their oxygen-carrying properties and mechanical strength, thereby reducing the need for fresh ilmenite and enhancing fuel flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ilmenite bed material is continuously used in fluidized bed boiler, then combustion process stability is maintained, but oxygen-carrying capacity and mechanical strength of ilmenite particles deteriorate over time

Engineering Contradiction:

Improvecombustion process stabilityVSAvoidmechanical strength of ilmenite particles

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent implements a bed material management system that continuously monitors particle properties and selectively removes deteriorated ilmenite particles from the fluidized bed. The system recovers functional ilmenite particles through separation processes and recirculates them back into the combustion chamber, maintaining combustion stability while replacing only the degraded material.

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The patent monitors changes in particle parameters such as oxygen-carrying capacity and mechanical strength over time. By detecting these parameter changes, the system identifies when ilmenite particles have deteriorated to a point where they need to be removed and replaced, optimizing the timing of particle replacement to maintain combustion reliability.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If ilmenite bed material is continuously used in fluidized bed boiler, then combustion process stability is maintained, but oxygen-carrying capacity and mechanical strength of ilmenite particles deteriorate over time

Engineering Contradiction:

Improvecombustion process stabilityVSAvoidconsumption of ilmenite

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent implements a bed material management system that continuously monitors particle properties and selectively removes deteriorated ilmenite particles from the fluidized bed. The system recovers functional ilmenite particles through separation processes and recirculates them back into the combustion chamber, maintaining combustion stability while replacing only the degraded material.

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The patent monitors changes in particle parameters such as oxygen-carrying capacity and mechanical strength over time. By detecting these parameter changes, the system identifies when ilmenite particles have deteriorated to a point where they need to be removed and replaced, optimizing the timing of particle replacement to maintain combustion reliability.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If mechanical classifier with mesh size 200 to 1,000 μm is used to separate bed material, then particle size classification is achieved, but fine particle fraction requires additional magnetic separation

Engineering Contradiction:

Improveparticle size classificationVSAvoidseparation process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent employs a two-stage separation process where a mechanical classifier with mesh size 200-1,000 μm performs initial particle size classification, dividing the bed material into coarse and fine fractions. This segmentation allows subsequent magnetic separation to be applied selectively to the fine particle fraction, reducing overall process complexity compared to treating the entire material stream.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different separation mechanisms to different particle size fractions. The mechanical classifier handles the bulk of the classification for larger particles, while magnetic separation is applied locally to the fine particle fraction where it is most effective, optimizing the overall separation process efficiency.

Inventive Principle:

Principle #3Local quality

4Manufacturing precision

If magnetic separator is used to classify fine particle fraction, then ilmenite particles are separated from ash, but recirculation system complexity increases

Engineering Contradiction:

Improveilmenite separation efficiencyVSAvoidrecirculation system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses a magnetic separator to extract ilmenite particles from the fine particle fraction of bed material. By removing and separately handling only the magnetic ilmenite component, the system achieves high separation efficiency while the recirculation system is designed to handle only the extracted ilmenite stream, managing complexity through selective extraction.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The magnetic separator acts as an intermediary device between the mechanical classifier and the recirculation system. It selectively separates ilmenite particles based on magnetic properties, providing a purified ilmenite stream for recirculation while managing the complexity of the overall separation and recirculation process.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 system allows for the efficient separation and recirculation of ilmenite particles, significantly reducing the consumption of ilmenite, improving combustion efficiency, and enabling better control of ilmenite concentration in the bed, making the process more environmentally friendly and economical.

Implementation Method 1

a mechanical classifier comprising a mesh size from 200 to 1,000 μm designed to separate a coarse and a fine particle size fraction

Methodology Applied

Scientific EffectMechanical classification through mesh screening: Filter (physical)

Implementation Method 2

a magnetic separator designed to magnetically classify the fine particle fraction from the mechanical classifier

Methodology Applied

Scientific EffectMagnetic separation: Magnetism

Implementation Method 3

Once the velocity of the fluidization gas rises above the minimum fluidization velocity, at which the force of the fluidization gas balances the gravity force acting on the particles, the solid bed material behaves in many ways similarly to a fluid

Methodology Applied

Scientific EffectFluidization: Fluidisation

Data Source

PatentUS11085635B2System and process for recycling fluidized boiler bed material

Publication Date: 2021.08.10 IMPROBED AB

AI summary

The invention relates to a system for recycling fluidized bed boiler bed material, comprising: a. a bottom ash removal device for removing bed material from a fluidized bed boiler, b. a mechanical classifier (10) comprising a mesh size from 200 to 1,000 μm designed to separate a coarse and a fine particle size fraction, c. a magnetic separator (12) designed to magnetically classify the fine particle fraction from the mechanical classifier, d. a device for recirculating the magnetic particle fraction into the boiler. The invention allows effective recirculation and reuse of ilmenite bed material.