Mechanical compaction of low-rank coal for water-resistant solid fuel
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Solution Overview
Problem
Low-rank coals with high moisture content are not suitable for gasification and liquefaction due to low energy efficiency and poor yield, as existing drying methods are costly or ineffective in preventing moisture reabsorption.
Innovation Solution
Mechanical high-pressure compaction to expel and prevent water reabsorption, followed by low-temperature drying to produce a high-energy, water-resistant solid fuel suitable for gasification and liquefaction processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If thermal drying methods are used to reduce moisture content, then moisture content is reduced, but production cost increases and product re-absorbs moisture
Solution Approach 1:
The patent replaces thermal drying methods with mechanical pressing. A press applies mechanical force to physically remove water from the fuel material through filtration and compression, eliminating the need for expensive thermal drying equipment and processes while achieving the same moisture reduction goal.
Solution Approach 2:
The patent introduces a filter medium as an intermediary between the fuel material and the collected water. This filter allows water to pass through while retaining the fuel material, enabling efficient separation and preventing re-absorption by maintaining physical separation between the dried material and water.
2Use of energy by moving object
If high-grade coal is used to produce slurry, then energy content is sufficient, but availability is limited and transportation cost is excessive
Solution Approach 1:
The patent changes the physical parameters of low-grade coal through mechanical pressing, reducing moisture content and increasing density. This parameter transformation converts abundant, low-cost low-grade coal into a high-energy-density fuel that can replace expensive high-grade coal in slurry production.
Solution Approach 2:
The patent utilizes abundant low-grade coal that would otherwise be economically unviable, transforming it into a useful fuel source. This approach replaces the need to transport expensive high-grade coal by locally processing inexpensive abundant material.
3Quantity of substance
If low rank coal with high moisture is used for gasification, then feedstock is available, but efficiency and synthesis gas yield are poor
Solution Approach 1:
The patent performs preliminary mechanical drying of low-rank coal before gasification processing. By removing excess moisture in advance through pressing, the fuel material achieves optimal moisture content for efficient gasification, improving synthesis gas yield and process efficiency without changing the feedstock source.
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 method efficiently reduces moisture content and prevents water reabsorption, resulting in a high-energy solid fuel that can be effectively used in gasification and liquefaction processes, overcoming the limitations of existing technologies.
Implementation Method 1
mechanically and efficiently transform the raw LRC under high pressure to collapse the porous structure, thereby expressing moisture contained in the pores
Implementation Method 2
collapsing the pores to prevent liquid water from reentering
Implementation Method 3
followed by low-temperature drying to produce a high-energy, water-resistant solid fuel
Data Source
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AI summary
The invention provides a method by which high moisture low rank coal or other carbonaceous material may be transformed into a high-energy, water resistant product. The raw feed is comminuted then mechanically compacted by a roller press with rolls of a specified profile to mobilize the inherent moisture and collapse most of the interstitial pore space. The mobilized moisture is then removed by low-temperature drying and the material is sized and shaped to form a product that is resistant to re-absorption of water or other liquids. The present invention will promote the use of low rank coal for liquefaction and gasification.