Solid Biomass Fuel Production via Torrefaction and Compression
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Solution Overview
Problem
Existing processes for producing solid biomass fuels from non-woody biomass sources face challenges in achieving high mechanical durability, bulk density, and uniformity, often requiring high compression ratios that increase costs and reduce process yield.
Innovation Solution
A process involving specific non-wood biomass sources, such as rice straw, tobacco straw, and hemp, combined with specific manufacturing steps, including pulverization, drying, molding with a controlled compression ratio, and torrefaction, to produce solid biomass fuels with high mechanical durability and performance properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high compression ratio is used in molding step, then mechanical durability and bulk density are improved, but process yield decreases and costs increase
Solution Approach 1:
The patent changes the compression ratio parameter from conventional high values (4-8) to a specific optimized range (2.5-4.0), which resolves the contradiction by achieving high mechanical durability (97% or greater) while maintaining acceptable process yield. This parameter optimization is the core invention that balances durability and productivity.
Solution Approach 2:
The patent applies preliminary action through pre-drying the biomass material to 10-20% moisture content before molding, and using pre-screened particles (0.5-5mm size). This preparation ensures that when molding at lower compression ratios, the material still achieves sufficient density and durability without requiring excessive compression force that would reduce yield.
2Quantity of substance
If high compression ratio is used in molding step, then bulk density is improved, but process costs increase
Solution Approach 1:
The patent optimizes the compression ratio parameter to the range of 2.5-4.0, which provides sufficient bulk density (0.6-0.8 g/cm³) without requiring the excessive compression forces that drive up energy consumption and equipment wear. This parameter change directly reduces operational costs while maintaining product quality.
3Manufacturing precision
If conventional pulverizing techniques are used on non-woody biomass, then particle homogeneity is poor, but processing costs are high
Solution Approach 1:
The patent uses a reference approach by adapting the successful wood-biomass processing methodology to non-woody biomass. The key is copying the multi-stage process (drying to 10-20% moisture, then pulping to 0.5-5mm particles) that worked for wood, and applying it to non-woody materials like rice straw, tobacco straw, and hemp, achieving comparable homogeneity and durability.
Solution Approach 2:
The patent applies preliminary drying to reduce moisture content to 10-20% before pulping. This pre-drying step is crucial for achieving homogeneous particles from non-woody biomass, as it prevents uneven moisture distribution that would otherwise require more aggressive (and costly) pulping operations.
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 process achieves solid biomass fuels with mechanical durability of 97% or greater, high bulk densities, water-proof properties, and high uniformity, while using a lower compression ratio, thereby increasing process yield and reducing costs.
Implementation Method 1
heating the molded biomass product to a temperature of from 110° C. to 500° C. for a time period of from 0.2 to 6 hours so as to provide a solid biomass fuel
Data Source
AI summary
A process for producing a solid biomass fuel, wherein the process comprises the following steps: (i) providing a biomass composition comprising biomass particles with an average particle diameter (D50) of from 1,000 m to 75,000 m; (ii) pulverising the biomass composition to provide a pulverised biomass powder with an average particle diameter (D50) of from 500 m to 10,000 m; (iii) drying the pulverised biomass powder so as to provide a dried pulverised biomass powder; (iv) molding the dried pulverised biomass powder so as to provide a molded biomass product; (v) heating the molded biomass product to a temperature of from 110 C to 500 C for a time period of from 0.2 to 6 hours so as to provide a solid biomass fuel; wherein the biomass composition comprises rice straw, tobacco straw, pepper straw, aubergine straw, cassava straw, yellow bean straw, chick pea straw, Glycine max straw, palm leaves, cashew shells, Chinese chestnut shells, pistachio shells, sunflower seed shells, walnut shells, pine nut shells, hemp, moso bamboo, hemp bamboo, arrow bamboo, lychee shells, cinnamon (logan) shells, snake skin fruit shells, mangosteen shells, durian shells, soybean residue, peanut residue, cassava residue, sweet potato residue, coffee bean residue, or combinations thereof.