Biomass Grading Pyrolysis Gasification in Circulating Fluidized Bed
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Solution Overview
Problem
Existing biomass gasification technologies face challenges in simultaneously eliminating tar and dust, resulting in unclean fuel gas products with low calorific value, high energy consumption, and increased operating costs, while also failing to effectively utilize silicon and potassium resources.
Innovation Solution
A method of biomass grading pyrolysis gasification in a circulating fluidized bed that integrates high-temperature tar removal and dust cleansing, utilizing multi-stage gas-solid separation and catalytic cracking with a heat carrier and semi-coke, which produces a high-calorific fuel gas without the need for additional filter materials or energy, and recycles materials for further combustion and gasification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional biomass gasification technologies are used, then fuel gas can be produced, but tar and dust cannot be simultaneously eliminated, resulting in unclean fuel gas with low calorific value
Solution Approach 1:
The gasification process is divided into multiple stages with different functions: drying zone, pyrolysis zone, oxidation zone, and reduction zone. Additionally, multi-stage gas-solid separation is implemented to remove particles of different sizes at different stages, achieving comprehensive dust and tar removal while preserving fuel gas quality
Solution Approach 2:
Catalytic materials are introduced as intermediaries to facilitate tar cracking and conversion. The catalysts promote the decomposition of tar into useful gases while reducing harmful substances, enabling effective tar removal without significantly impacting fuel gas calorific value
2Manufacturing precision
If additional filter materials and high-temperature treatment are used to remove tar and dust, then fuel gas cleanliness improves, but energy consumption increases and operating costs rise
Solution Approach 1:
The patent combines tar removal, dust removal, and calorific value enhancement into a single integrated process. The catalytic cracking unit simultaneously cracks tar into useful gases and removes dust through gravity separation, eliminating the need for separate high-energy filtration systems while actually increasing fuel gas calorific value
Solution Approach 2:
Instead of simply removing tar as a harmful substance, the process converts tar into useful combustible gases through catalytic cracking. This transforms the harmful tar into beneficial fuel components, reducing energy consumption compared to high-temperature incineration methods while improving fuel gas quality
3Manufacturing precision
If high-temperature gasification is used to eliminate tar, then fuel gas cleanliness improves, but equipment investment and operating complexity increase
Solution Approach 1:
The patent optimizes temperature parameters at different zones rather than using uniform high temperature throughout. The oxidation zone operates at high temperature for efficient combustion, while the reduction zone operates at lower temperature for tar cracking, reducing overall energy input and equipment complexity compared to full high-temperature processing
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 method achieves a fuel gas product that is essentially free of tar and ash, with high thermal efficiency, low energy consumption, and no secondary pollution, suitable for power generation and industrial applications, while effectively utilizing silicon and potassium resources.
Implementation Method 1
the tar in the third-level crude fuel gas contacts with the large particle carrier and the semi-coke at a temperature of 700-850° C. to carry out a second catalytic cracking
Implementation Method 2
subjecting the catalytic cracking product to the multi-stage gas-solid separation
Implementation Method 3
mixing, in the carrying fluidized bed, the high temperature synthesis gas and a heat carrier having a temperature of 750-950° C. from the turbulent fluidized bed with the biomass particles, and heating the biomass particles
Implementation Method 4
heating the biomass particles to carry out a high temperature hydro-rapid pyrolysis reaction
Implementation Method 5
reacting with oxidant and water vapor at the temperature of 800-1,100° C. to generate gasified coal gas
Data Source
AI summary
The invention provides a method of biomass grading pyrolysis gasification in a circulating fluidized bed comprising: feeding biomass into the lower-middle part of a carrying fluidized bed, mixing with high temperature synthesis gas and heat carrier from a turbulent fluidized bed, heating the biomass to carry out a pyrolysis reaction, and carrying the pyrolysis product upward; subjecting the cracked oil and gas to a gaseous phase catalytic cracking in an upper-middle part of the carrying fluidized bed, cracking the tar into methane, ethane and the like; subjecting the heat carrier, semi-coke and fuel gas after the reaction to the multi-stage of gas-solid separation, a large particle carrier and semi-coke following a first-level separation are used as the fuel gas cracking catalyst and the filter material for filtering and removing dust, and enter into a moving bed filter to separate out an ultra-fine ash and subsequently return to the turbulent fluidized bed so as to perform gasification reaction, the ultra-fine ash is delivered to the outside as a silicon-potash fertilizer product; the medium and small particle carrier and semi-coke separated from a second-level separation are directly recycled to the turbulent fluidized bed, the fine particles separated from a third-level separation is discharged to the outside as a silicon-potash fertilizer product, the moving bed filter further catalytically cracks a small amount of tar in the fuel gas into methane and ethane and removes the ultra-fine ash simultaneously, the purified fuel gas is delivered to the outside as a product.