Fermentation Heat Drying Organic Waste to Solid Fuel
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Solution Overview
Problem
Existing methods for drying wet organic materials to a low enough moisture level for use as a combustible solid fuel are energetically inefficient, consuming excessive amounts of energy and failing to produce a commercially viable product.
Innovation Solution
The method involves using heat generated by microbial action through fermentation of the organic material itself, with a two-stage process: fermentation to produce hot exhaust gases, followed by air-to-air heat exchange to generate heated air for drying, and sequential distribution of this air through the material to reduce moisture content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If conventional external heat sources (fossil fuel, electricity) are used to dry organic waste, then the water content can be reduced to 20%, but the energy consumption becomes excessive and the process is not energetically economical
Solution Approach 1:
The organic waste material serves its own drying needs by undergoing fermentation that generates internal heat. The material transforms from a passive object requiring external energy input to an active system that produces its own drying energy through microbial action, thereby eliminating the need for external fossil fuel or electricity inputs.
Solution Approach 2:
The high moisture content, which is normally a disadvantage for fuel production, is converted into a benefit. The water present in the waste material supports microbial fermentation, which in turn generates the heat needed for drying. The harmful excess moisture becomes the enabling condition for self-heating through fermentation.
2Quantity of substance
If mechanical means (belt presses, screw presses, centrifuges) are used to remove water from organic material, then free (interstitial) water can be removed, but water from within constituent cells cannot be removed and lower water content levels necessary for practical fuel cannot be achieved
Solution Approach 1:
The invention utilizes the phase transition of water from liquid to vapor through fermentation-generated heat. The microbial action raises the temperature of the material, causing intracellular water to evaporate and escape, achieving deep drying that mechanical means cannot accomplish.
Solution Approach 2:
Mechanical pressing and centrifugal forces are replaced with a biological-thermal system. Instead of using mechanical energy to physically force water out, the system uses microbial fermentation to generate thermal energy that evaporates water from within cells, achieving much lower moisture contents.
3Manufacturing precision
If rotary dryers or fluid bed dryers using hot flue gases are used, then drying can be achieved, but the process consumes undue amounts of energy and is impractical for preparing commercially useful fuels
Solution Approach 1:
The waste material generates its own drying energy through fermentation, eliminating dependence on external energy sources. The system is self-sufficient, using the material's own biochemical processes to produce the heat required for moisture removal.
Solution Approach 2:
The invention changes the energy source parameter from external fossil fuel/electricity to internal biochemical energy. By controlling fermentation conditions, the system transforms the energy parameters of the process, achieving drying at lower net energy input through the exothermic microbial degradation of organic matter.
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 approach allows for efficient drying of organic waste from 65% to 20% moisture or lower, making the end product a commercially practical and economical solid fuel, with a calculated energy output of 40-50 kW of biofuel per kW used.
Implementation Method 1
heat which has been generated by microbial action (partial aerobic decomposition or fermentation) acting on that very same organic material
Implementation Method 2
hot exhaust gases generated by the fermentation of the organic waste
Implementation Method 3
withdrawing hot exhaust gases generated by the fermentation of the organic waste and effecting an air-to-air heat exchange with clean ambient intake air to produce a stream of heated air for drying
Implementation Method 4
distributing hot air from said stream through the material to bring it to a desired state of dryness
Data Source
AI summary
Organic waste having a moisture content of about 65% is dried to a level of dryness by applying heat generated by microbial action on the waste organic material to dry that material to usable levels of about 20% moisture. Method of the present invention is more efficient and economical for the drying of waste materials to combustible fuel than conventional drying methods and apparatus. Preblended portions of the organic material are deposited sequentially into a fermentation zone of a chamber and hot exhaust gases generated by the fermentation process are passed through an air-to-air heat exchanger along with cooler ambient intake air which is in its turn heated and turned back on the waste material in the second drying stage.