Torrefaction Process Heating That Burns Tar-Laden Syngas
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Solution Overview
Problem
Conventional torrefaction processes produce biocoal with varying energy densities and high tar content, which can foul gas engines and require additional processing, posing health and safety risks.
Innovation Solution
A torrefaction apparatus and method that maintains syngas temperature above condensation levels, combusting tar in an oxidizer to generate thermal energy for heating the process chamber, thereby reducing tar release and increasing biocoal energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the temperature and residence time are increased to achieve higher energy density biocoal, then the energy density increases, but the tar content in syngas increases significantly
Solution Approach 1:
The patent applies this principle by converting the harmful tar in syngas into a beneficial heat source through combustion in the oxidizer chamber. The tar that would normally foul engines or require complex removal is instead burned to provide thermal energy for the torrefaction process, eliminating the harmful effect while creating a useful one. This resolves the contradiction by allowing high energy density production without the penalty of harmful tar accumulation.
Solution Approach 2:
The patent changes the temperature parameter of the syngas from condensation temperature to combustion temperature by introducing it to the oxidizer chamber. This parameter change transforms the syngas from a state where tar would condense and cause problems to a state where tar is combusted beneficially. The syngas temperature is maintained above condensation levels throughout the system, preventing tar deposition while enabling its use as fuel.
2Reliability
If tar is removed from syngas through condensation and separation, then the syngas can be used in conventional applications, but the process complexity and equipment requirements increase
Solution Approach 1:
Instead of removing tar through complex separation equipment, the patent converts the harmful tar into a beneficial fuel source by combusting it in the oxidizer chamber. This eliminates the need for condensation tanks, separators, and associated complex equipment, while still producing high-quality biocoal. The tar becomes part of the heat generation system rather than a contaminant to be removed.
Solution Approach 2:
The patent extracts the tar from the syngas stream not through physical separation but through combustion in the oxidizer chamber. The tar is taken out of the gas phase and converted to heat energy, which then heats the torrefaction chamber. This extraction method is simpler than physical separation and simultaneously eliminates the harmful effect while recovering energy.
3Ease of manufacture
If the syngas is cooled to condense and remove tar, then the tar can be separated, but the energy loss from cooling and the risk of spontaneous condensation increase
Solution Approach 1:
Instead of cooling the syngas to condense tar, the patent inverts the approach by heating the syngas above condensation temperature and combusting the tar in the oxidizer chamber. This inversion eliminates the need for cooling energy input and prevents spontaneous condensation risks. The tar is removed through combustion rather than condensation, completely reversing the conventional approach.
Solution Approach 2:
The patent changes the temperature parameter of syngas from below condensation temperature to above condensation temperature. By maintaining syngas temperature above the dew point throughout the system, tar condensation is prevented entirely. The tar is then removed through combustion at high temperature rather than condensation at low temperature, eliminating energy loss from cooling.
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 apparatus achieves biocoal with enhanced energy density up to 30 GJ/ton, reduces tar production, and enables safe handling and storage, suitable for energy and steel production applications.
Implementation Method 1
combusting tar in an oxidizer to generate thermal energy for heating the process chamber
Implementation Method 2
torrefaction is a pyrolysis process under essentially atmospheric pressure, essentially in absence of oxygen other than the oxygen contained in the biomass itself
Implementation Method 3
The subject invention utilizes thermal conduction to torrefy the biomass in a vibratory reactor in which a heated solid unperforated plate is sealed in the reactor
Data Source
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AI summary
A torrefaction method comprises forwarding biomass through a process chamber; heating the biomass in the process chamber to a predetermined temperature and pyrolyzing the biomass to release syngas from the biomass, wherein the syngas contains at least 20% of the power contained in the flow of the biomass; and oxidizing the syngas to heat the biomass in the process chamber.