Coal Dust Ceramic Proppant Strength Density Trade-off
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Solution Overview
Problem
Current proppants face a trade-off between mechanical strength and density, with higher strength requiring higher density, which increases costs and complexity, and existing proppants fail to meet all industry standards for strength, sphericity, and cost effectively.
Innovation Solution
A proppant comprising a pyrolyzed mixture of coal dust and polymer-derived ceramic composite, with coal dust making up 40-90% of the mixture, combined with solvents and additives to create ceramic beads with tailored microstructures and porosity, achieving high compressive strength and low density, and sphericity greater than 0.9.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If proppant particle size is increased to improve permeability, then gas flow is improved, but mechanical strength decreases under high closure stresses
Solution Approach 1:
The patent uses composite materials by combining coal dust particles with a polymer-derived ceramic matrix. The coal dust provides permeability and spherical shape, while the polymer-derived ceramic provides mechanical strength and structural integrity. This composite structure allows the proppant to maintain both high permeability and sufficient strength under closure stresses.
Solution Approach 2:
The patent applies local quality by creating a core-shell structure where the core is composed of coal dust particles providing permeability, and the shell is composed of polymer-derived ceramic providing strength. This localized differentiation allows each material to perform its specific function optimally within the overall proppant structure.
2Strength
If proppant density is increased to improve strength, then mechanical strength is improved, but transportation costs and pumping pressures increase
Solution Approach 1:
The patent combines low-density coal dust particles with polymer-derived ceramic to create a composite proppant that achieves sufficient strength without requiring high density. The polymer-derived ceramic matrix provides structural support while maintaining overall low density, thus reducing transportation costs and pumping pressures.
Solution Approach 2:
The patent changes the density parameter by using coal dust with controlled density (less than 2.5 g/cc) and optimizing the composition ratio of coal dust to polymer-derived ceramic. This parameter optimization allows the proppant to achieve the required strength while maintaining low density for cost-effective transportation and installation.
3Strength
If proppant sphericity is increased to improve crush strength, then fewer fines are produced, but manufacturing complexity increases
Solution Approach 1:
The patent utilizes spheroidality by selecting and using coal dust particles that are inherently spherical or near-spherical in shape. This natural spherical geometry of the coal dust particles, combined with the polymer-derived ceramic matrix, results in proppants with high sphericity (greater than 0.6) and roundness (greater than 0.6), reducing crush strength tests and fine generation without requiring complex manufacturing processes.
4Strength
If polymer content is increased to improve strength, then compressive strength is improved, but cost increases
Solution Approach 1:
The patent optimizes the parameter of polymer content by establishing a specific composition range: 10-40% coal dust and 60-90% polymer-derived ceramic by weight. This optimized ratio ensures sufficient compressive strength (at least 2000 psi) while minimizing the use of expensive polymer materials, thereby reducing overall cost.
Solution Approach 2:
The patent applies local quality by concentrating the polymer-derived ceramic material in the shell and matrix regions where strength is most needed, while using cheaper coal dust in the core regions. This localized material distribution optimizes the strength-to-cost ratio by placing expensive materials only where structurally necessary.
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 composite proppant exhibits compressive fracture strength of at least 2000 psi, meets industry standards for fracture closure stresses, and is cost-effective, with a density less than 1.8 g/cc, making it suitable for fracking applications while reducing transportation costs.
Implementation Method 1
a proppant comprising a pyrolyzed mixture of coal dust and polymer derived ceramic composite
Data Source
AI summary
A material useful as a proppant comprises a core chemically reacted in situ from coal dust and a polymer derived ceramic material, such that at least a portion of the coal dust is chemically converted to a ceramic, nanoparticles, graphene, nanofibers or combinations of any of these.