Ultra-fine coal agglomeration using low-surface-energy film
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Solution Overview
Problem
The existing methods for forming agglomerates of ultra-fine coal particles are costly and inefficient, requiring high amounts of binders, which makes them impractical for widespread commercial use due to high binder input costs and the issue of fine coal particles being impounded as waste.
Innovation Solution
The use of a film-forming agglomeration aid (FFAA) with a lower surface energy than the ultra-fine coal particles to coat and agglomerate them, allowing for the formation of strong and durable briquettes or pellets with binder amounts less than 3% by weight, enabling efficient transportation and saleability across all coal markets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high amounts of binders are used to form agglomerates of ultra-fine coal particles, then the agglomerates achieve sufficient strength for transportation, but the cost of binder exceeds the market value of the coal product
Solution Approach 1:
The invention changes the chemical composition parameters of the binder from conventional organic binders (starches, lignosulfonates, tars, pitches, asphalts) to inorganic binders consisting of at least one alkaline earth metal salt and at least one aluminum salt. This parameter change enables achieving sufficient agglomerate strength with binder amounts less than 3% by weight, resolving the contradiction between strength and binder quantity.
2Ease of manufacture
If conventional binders are used to coat ultra-fine coal particles, then agglomeration is achieved, but the binder cost becomes prohibitively high relative to coal market value
Solution Approach 1:
The invention substitutes conventional organic binders with inorganic binder systems comprising alkaline earth metal salts and aluminum salts. This parameter change maintains ease of manufacture through simple mixing and drying processes while reducing binder cost to less than 3% by weight, making the agglomeration process economically viable for coal products.
3Productivity
If ultra-fine coal particles are produced through normal industrial sizing and crushing, then coal processing is complete, but fine particles are impounded as refuse due to poor agglomeration properties
Solution Approach 1:
The invention converts the harmful effect of ultra-fine particles being impounded as refuse into a beneficial outcome by developing an agglomeration method that effectively binds these particles into usable fuel products. The inorganic binder system successfully agglomerates ultra-fine particles that were previously unsuitable for commercial use, eliminating waste and improving overall processing efficiency.
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 results in agglomerates that maintain structural integrity during transportation, absorb minimal water, and are cost-effective, eliminating the need for high binder usage and reducing waste, thus creating new market opportunities for ultra-fine coal particles.
Implementation Method 1
A film-forming agglomeration aid (FFAA) is used to create coherent and strong agglomerates of ultra-fine coal particles while minimizing the amount used for this purpose. The film forming agglomeration aid is predominantly hydrophobic, having a lower surface energy relative to a surface of the ultra-fine coal particles which is coated by the FFAA.
Data Source
AI summary
A method of preparing agglomerates of ultra-fine coal particles includes mixing a film forming agglomeration aid (FFAA) with a quantity of ultra-fine coal particles to form ultra-fine coal particles coated with the FFAA. The FFAA has a lower surface energy relative to a surface of the ultra-fine coal particles. The FFAA is mixed with the ultra-fine coal particles in an amount less than 3% by weight of the ultra-fine coal particles on a dry basis. Agglomerates of the ultra-fine coal particles coated with the film forming agglomeration aid are formed using vibration, pelleting, and/or briquetting. The agglomerates have a size of at least 2 mm. The ultra-fine coal particles have a particle size less than 100 μm. The agglomerate has a tumbler test friability less than 3%. The drop shatter friability is also less than 3%.