Biomass Pyrolysis Apparatus with Indirect Heating and Gas Recycle
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Solution Overview
Problem
Conventional coal-fired thermal power generation systems using semi-carbonization methods face issues with limited heat retention in torrefied materials, fluctuating grindability due to raw material properties and moisture content, leading to decreased power generation and increased equipment costs for stable fuel supply.
Innovation Solution
A biomass pyrolysis apparatus with a combustion furnace producing stable fuel for a pyrolysis gasification furnace, which pyrolyzes woody biomass to produce torrefied material and pyrolysis gas, and introduces the pyrolysis gas into a boiler with the torrefied material, utilizing indirect heating and a control device to maintain optimal pyrolysis gasification temperature for improved grindability and heat utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the pyrolysis gasification temperature is increased to improve the grindability of torrefied material, then the grindability is improved, but the heat quantity remaining in the torrefied material decreases
Solution Approach 1:
The system separates the utilization paths of pyrolysis gas and torrefied material. Pyrolysis gas is directed to the boiler for combustion, while torrefied material is sent to the pulverizer. This segmentation allows independent optimization of each path - gas provides immediate energy, while solid material is processed for fuel preparation
Solution Approach 2:
The system changes the operational parameters by controlling pyrolysis gasification temperature within a specific range (200-400°C) and utilizing the pyrolysis gas directly in the boiler. This parameter optimization ensures sufficient thermal decomposition for grindability while preserving heat content in the torrefied material
2Loss of energy
If the pyrolysis gasification temperature is decreased to retain more heat in torrefied material, then the heat quantity remaining increases, but the grindability of torrefied material decreases
Solution Approach 1:
The pyrolysis gas produced during torrefaction is utilized to combust in the boiler, providing self-service energy recovery. This eliminates the need for external fuel to maintain pyrolysis temperature, allowing heat retention in torrefied material while still achieving sufficient decomposition for grindability
3Reliability
If the amount of torrefied material supplied to the pulverizer is reduced to avoid power overload, then the pulverizer operates within permissible values, but the stable mixed fuel burning ratio cannot be achieved
Solution Approach 1:
The pyrolysis gas introduction passage serves multiple functions: it provides combustion fuel to the boiler, enables stable mixed fuel burning ratio, and eliminates the need for buffer tanks. This multi-functionality resolves the contradiction by achieving both reliable pulverizer operation and stable fuel composition through gas supplementation
4Stability of the object's composition
If buffer tanks are added to provide stable supply of torrefied material, then the stable mixed fuel burning ratio is achieved, but the equipment costs increase
Solution Approach 1:
The system extracts and utilizes the pyrolysis gas produced during torrefaction, directing it to the boiler for combustion. This extraction of useful energy from the pyrolysis process eliminates the need for buffer tanks, reducing equipment complexity and costs while maintaining stable fuel supply composition
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 configuration effectively utilizes all heat from woody biomass, stabilizes torrefied material production, reduces equipment costs by eliminating the need for buffer tanks, and maintains constant power generation by optimizing pyrolysis gas and torrefied material supply.
Implementation Method 1
a combustion furnace that produces a heat quantity by causing a stable property fuel to combust
Implementation Method 2
a pyrolysis gasification furnace that produces a torrefied material and a pyrolysis gas by pyrolyzing a woody biomass
Implementation Method 3
utilizing indirect heating
Data Source
AI summary
Provided is a biomass pyrolysis apparatus comprising: a combustion furnace that produces a heat quantity by causing a stable property fuel to combust; a pyrolysis gasification furnace that produces a torrefied material, and a pyrolysis gas by pyrolyzing woody biomass by a heat quantity produced by the combustion furnace; and a pyrolysis gas introduction passage that introduces the pyrolysis gas from the pyrolysis gasification furnace into a boiler, into which the torrefied material is introduced.