Biomass Torrefaction Facility with Gas Recirculation
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Solution Overview
Problem
Torrefied biomass solid fuels, or 'black pellets,' experience organic component elution when stored outdoors, posing environmental concerns due to their hydrophobic nature, which is not a significant issue with coal, necessitating a manufacturing facility that minimizes organic component elution.
Innovation Solution
A manufacturing facility for biomass solid fuel that includes a preheater, reactor, circulation path for torrefaction gas, combustor, and heat exchangers to efficiently process biomass pellets, generating heating gas for preheating and utilizing combustion gas for energy exchange, thereby reducing moisture absorption and organic component elution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If black pellets are stored outdoors to eliminate silo facility requirements, then storage facility complexity is reduced, but organic component elution occurs causing environmental harm
Solution Approach 1:
The patent applies parameter changes by controlling the torrefaction temperature (150-350°C) and oxygen concentration (5-21%) during manufacturing to alter the chemical structure of the biomass. This thermal treatment reduces the organic components that cause elution while maintaining the hydrophobic properties needed for outdoor storage, thus resolving the contradiction between storage simplicity and environmental harm.
Solution Approach 2:
The patent applies preliminary action by performing torrefaction treatment before storage to pre-modify the biomass structure. The preheating unit heats the biomass to 100-150°C before torrefaction, and the torrefaction process itself prepares the material in advance to resist organic component elution during subsequent outdoor storage, eliminating the need for silos while preventing pollution.
2Reliability
If torrefaction is performed to enhance crushability and mixed combustion rate, then fuel performance is improved, but energy consumption increases
Solution Approach 1:
The patent applies self-service by using the biomass itself as the fuel source for torrefiction. The biomass pellets are fed into the torrefaction furnace where they are heated by combustion of part of the biomass material. This self-heating process reduces external energy input while achieving the desired torrefaction effects for improved crushability and combustion performance.
Solution Approach 2:
The patent merges the heating function with the torrefaction process by integrating the preheating unit with the torrefaction furnace. The preheating unit recovers heat from the torrefaction process to preheat incoming biomass, combining thermal processing steps to reduce overall energy consumption while maintaining improved fuel performance.
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 facility effectively produces hydrophobic black pellets with reduced organic component elution, allowing for outdoor storage without environmental impact, utilizing energy efficiently and preventing surface degradation.
Implementation Method 1
a preheater configured to preheat the pellets; a heat source for preheating
Implementation Method 2
a reactor configured to torrefy the pellets preheated by the preheater
Implementation Method 3
a circulation path connecting a gas outlet of the reactor and a gas inlet of the reactor and configured to circulate a torrefaction gas generated during torrefaction of the pellets in the reactor
Implementation Method 4
a combustor configured to receive the torrefaction gas flowing through the branch flow path and combust the torrefaction gas
Implementation Method 5
a first heat exchanger provided in the circulation path; a first combustion gas flow path connecting the combustor and the first heat exchanger and configured to flow the combustion gas therethrough that is generated in the combustor, the first heat exchanger being configured to exchange heat between the combustion gas generated in the combustor and the torrefaction gas circulating in the circulation path
Data Source
AI summary
A manufacturing facility of biomass solid fuel includes: a preheater for preheating pellets; a heat source for preheating; a reactor that torrefies the pellets preheated by the preheater; a circulation path that connects a gas outlet and a gas inlet of the reactor and circulates torrefaction gas generated during torrefaction of the pellets in the reactor, a branch flow path branched from the circulation path to flow the torrefaction gas therethrough; a combustor that receives the torrefaction gas flowing through the branch flow path and combusts the torrefaction gas; a first heat exchanger provided in the circulation path; and a first combustion gas flow path connecting the combustor and the first heat exchanger to flow combustion gas generated in the combustor. The first heat exchanger exchanges heat between the combustion gas generated in the combustor and the torrefaction gas circulating in the circulation path.