Biomass Gasifier Staged Reactor Design
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Solution Overview
Problem
Existing biomass gasifiers achieve low conversion and high impurity levels, particularly tars, due to inadequate gas-solid contact and inefficient gasification processes, limiting the use of produced fuel gases in internal combustion engines and other applications without additional purification.
Innovation Solution
A biomass gasifier with a staged process involving pre-, main, and secondary reactors, where biomass is pyrolyzed and gasified with internal heating elements and a high degree of filling in the secondary reactor, enhancing gas-solid contact and energy input, resulting in a cleaner fuel gas with high hydrogen and carbon monoxide content and reduced impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If biomass is pushed as a bed through the bottom of the screw reactor with gas not constrained to flow through the bed, then the gasifier structure is simple, but gas-solid contact is insufficient resulting in low conversion
Solution Approach 1:
The reactor is designed with a porous or permeable structure that allows gas to flow through the solid bed from multiple directions, increasing the contact surface area between gas and biomass without requiring complex internal structures. This enables efficient mass transfer and high conversion while maintaining structural simplicity.
2Use of energy by moving object
If external heating alone is used, then the heating system is simple, but insufficient energy is supplied leading to inadequate gasification
Solution Approach 1:
Heating elements are nested within the reactor structure, with internal heating components positioned concentrically around the biomass bed. This nested arrangement allows multiple heating zones at different temperatures to be integrated into a single compact system, providing sufficient energy input without excessive structural complexity.
Solution Approach 2:
A heat transfer medium or thermal conductor is introduced as an intermediary between the external heat source and the biomass. This mediator efficiently transfers thermal energy from the heating elements to the gasification zone, ensuring adequate energy supply while keeping the heating system design manageable.
3Object-generated harmful factors
If the discharge line is not filled with solid bed, then the conveying system is simple, but gas does not flow through solid bed and secondary degradation of tars does not occur
Solution Approach 1:
The discharge line is pre-configured with a solid bed packing arrangement that forces gas to flow through the bed before discharge. This preliminary structuring of the discharge path ensures that gas undergoes secondary degradation of tars as it passes through the hot solid bed, reducing impurity content without requiring additional complex purification equipment.
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 solution achieves higher gasification conversion and produces a fuel gas suitable for use in heat engines with minimal impurities, allowing for direct application without further purification, and generates a high-quality solid carbonaceous residue as a fuel.
Implementation Method 1
one or more elongated heating elements in the core(s) of the transport screw(s), which, in addition to heating from the outside, heats/heats the interior of the main reactor without an exchange of the heat transfer medium with the interior of the main reactor, i.e. the heat transfer takes place through the walls of the core into the interior of the reactor
Implementation Method 2
the transport screw of the main reactor has blades in order to lift the masses to be gasified against gravity and to allow them to fall back into the packed bed when the blades continue to move in a specific position
Implementation Method 3
In the pre-reactor, however, pyrolysis of the biomass takes place at the same time with a lack of oxygen
Data Source
AI summary
The invention relates to a biomass gasifier for the pyrolysis and/or partial gasification of biomass in order to produce a fuel gas or fuel gas mixture, comprising a prereactor, a main reactor (2) that is heated both inside and outside and comprises a conveyor screw (4), and a secondary reactor (3). The invention also relates to a method for processing biomass in the biomass gasifier.