Biomass Gasifier Segmented Reactor for Tar-Free Product Gas
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Solution Overview
Problem
Conventional biomass gasifiers suffer from incomplete pyrolysis, resulting in product gas containing high levels of tar and being unsuitable for engines and fuel cells, and are limited by constant, continuous operation, making them inefficient for power fluctuations or partial loads.
Innovation Solution
A biomass gasification method where the raw material is completely outgassed in the pyrolysis unit, converting into a solid and gas/vapor phase, allowing for complete cracking in the oxidation unit, and utilizing a fluidized bed in the reduction unit to ensure efficient conversion, with heat recovery and adjustable performance to maintain consistent gas quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional biomass gasifiers operate with incomplete pyrolysis, then the operation can be simpler, but the product gas contains high levels of tar making it unsuitable for engines and fuel cells
Solution Approach 1:
The gasifier is divided into three distinct zones arranged in series: pyrolysis zone, oxidation zone, and reduction zone. Each zone performs a specific function - the pyrolysis zone completely decomposes biomass into volatile matter and char, the oxidation zone burns part of the volatile matter to provide heat, and the reduction zone converts CO2 and H2O into CO and H2 using the char. This segmentation ensures complete pyrolysis and tar-free product gas while maintaining operational simplicity through zoned functionality.
2Device complexity
If conventional biomass gasifiers are designed for constant continuous operation, then the system structure can be simpler, but the system cannot adapt to power fluctuations or partial loads
Solution Approach 1:
The gasifier incorporates adjustable feed rates for biomass and air, allowing dynamic operation across different load conditions. The three-zone structure with controlled air injection points enables the system to adapt to power fluctuations and partial loads while maintaining efficient gasification. This dynamic capability is achieved without significantly increasing structural complexity, as the same three-zone configuration handles both constant and variable operation modes.
3Object-generated harmful factors
If the pyrolysis unit operates at higher temperatures to ensure complete outgassing, then the product gas quality improves, but the energy consumption increases
Solution Approach 1:
The oxidation zone burns a portion of the volatile matter produced in the pyrolysis zone, generating heat that is immediately utilized in the reduction zone to drive the endothermic reduction reactions. This internal heat generation and utilization system eliminates the need for external energy input, achieving complete pyrolysis and high-quality product gas without increasing overall energy consumption. The system is self-sufficient, with each zone providing energy for the next.
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 method produces tar-free product gas, enabling flexible operation and consistent quality, suitable for engines and fuel cells, and allows for wide performance range adjustments without compromising gas quality, enhancing the efficiency and usability of the biomass gasifier.
Implementation Method 1
the raw material in the Pyrolysis unit is outgassed and converted into the pyrolysis products
Implementation Method 2
the pyrolysis products being partially burned in the oxidation unit with the addition of a gasification agent
Implementation Method 3
the oxidation products being converted into product gas in the reduction unit
Data Source
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AI summary
In order to gasify biomass, the raw material (12) is supplied to a gasification reactor (32) via a supply device (10), a pyrolysis unit (14), an oxidation unit (16) and a reduction unit (18) being arranged in direct contact with one another in said reactor. The raw material (12) is degassed in the pyrolysis unit (14) and is converted to the pyrolysis products. The pyrolysis products are burnt in the oxidation unit (16) while a gasification agent (44) is supplied. The oxidation products are converted to product gas (22) in the reduction unit (18) and the product gas (22) is removed from the gasification reactor (32) via an outlet (20). At least part of the product gas (22) is used to heat the raw material (12) in the pyrolysis unit (14), the raw material (12) being completely degassed in the pyrolysis unit (14) and being completely separated to give a solid phase consisting of carbon and a gaseous phase consisting of the pyrolysis gases.