Low Rank Coal Processing Under Vacuum Conditions
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Solution Overview
Problem
Low rank coal, such as lignite, is difficult to process due to its high moisture content and brittle nature, requiring significant energy input and resulting in the creation of coal fines, which are hazardous and of little use, and current methods for moisture removal often involve pulverization, leading to handling and transport challenges.
Innovation Solution
A method involving placing low rank coal with a heat content between 3,000 BTU/lb and 9,000 BTU/lb in a vessel, exposing it to heat and pressure less than atmospheric pressure to reduce the primary particle size, and combining it with a binder to form a fuel composition, which is then shaped to yield a stable and transportable solid fuel product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If low rank coal is processed using conventional methods, then moisture content is removed, but significant energy input is required and coal fines are created
Solution Approach 1:
The patent applies parameter changes by controlling pressure and temperature conditions during coal processing. Specifically, the coal is processed at pressures below atmospheric pressure (vacuum conditions) and controlled temperatures to reduce particle size and remove moisture simultaneously, thereby reducing energy input and minimizing coal fines generation
Solution Approach 2:
The patent creates a composite fuel product by combining processed low rank coal with binder materials. This composite approach allows the coal to be formed into stable fuel pellets or briquettes that reduce dust generation while maintaining energy content and improving handling properties
2Quantity of substance
If low rank coal is pulverized to remove moisture, then moisture content is reduced, but handling and transport challenges increase
Solution Approach 1:
The patent segments the coal processing into controlled stages under vacuum conditions, reducing particle size to a程度 that facilitates moisture removal while preventing excessive pulverization that would create unmanageable dust. The binder then consolidates these particles into handleable fuel forms
Solution Approach 2:
The binder material serves as an intermediary that bridges the gap between pulverized coal and handleable fuel. It binds the fine coal particles together into stable pellets or briquettes that are easy to handle and transport while maintaining the moisture-reduced state
3Use of energy by moving object
If low rank coal is processed to reduce particle size, then energy content per weight increases, but coal fines are generated
Solution Approach 1:
The patent changes pressure parameters to sub-atmospheric levels during processing, which allows particle size reduction through controlled mechanisms rather than aggressive pulverization. This achieves energy density improvement while minimizing harmful fine dust generation
Solution Approach 2:
The patent converts what would normally be harmful coal fines into beneficial fuel components by using the binder to incorporate them into stable fuel pellets. The fine particles that would normally be wasted or hazardous become part of the useful fuel product
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 increases the energy content of the coal on a per weight basis, reduces the amount of coal needed, and minimizes environmental impact by converting untransportable coal fines into a stable solid fuel, reducing the negative effects of coal combustion emissions and the demand for coal.
Implementation Method 1
The coal is exposed to heat and a pressure less than atmospheric pressure within the vessel, thereby reducing a primary particle size of the coal
Implementation Method 2
The coal is exposed to heat and a pressure less than atmospheric pressure within the vessel
Implementation Method 3
A binder is introduced to the vessel, such that the coal combines with the binder to yield a mixture
Data Source
AI summary
A method of preparing a fuel composition includes placing coal having a heat content between about 3,000 BTU/lb and about 9,000 BTU/lb and a moisture content between about 20 wt % and about 60 wt % in a vessel. The coal is exposed to heat and a pressure less than atmospheric pressure within the vessel, thereby reducing the coal, such that an average primary particle size of the coal is less than 1 millimeter. A binder is introduced to the vessel, such that the coal combines with the binder to yield a mixture. The mixture is shaped to yield a fuel composition.