Rotary Shear Comminution for Uniform Corn Stover Particles
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Solution Overview
Problem
Current biomass comminution processes, such as hammer milling and grinding, often fail to produce uniform particle sizes and shapes, leading to increased energy consumption and feedstock recalcitrance in biofuel production, as they tend to break biomass along the grain rather than across, and require dry conditions, which is energy-intensive and unfavorable for conversion processing.
Innovation Solution
A rotary bypass shear comminution process that feeds corn stover or wood chips in a direction random to the grain through counter-rotating intermeshing arrays of cutting discs, allowing for multiple passes to achieve uniform particle size and shape, high skeletal surface area, and optimal flow properties, while maintaining moisture above the fiber saturation point to minimize recalcitrance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hammer milling or grinding is used to comminute biomass, then particle size reduction is achieved, but particle shape uniformity deteriorates and energy consumption increases
Solution Approach 1:
The comminution process is divided into multiple discrete cutting passes through counter-rotating discs, each pass producing more uniform particles. The segmentation of the comminution action into sequential cutting stages allows progressive size reduction with improving uniformity, avoiding the energy-intensive single-pass grinding approaches.
Solution Approach 2:
The invention changes the cutting parameters by using counter-rotating discs with specific rotational speeds and blade configurations. By controlling the relative motion parameters between the discs and feedstock, the process achieves superior particle shape uniformity while maintaining lower energy consumption compared to conventional grinding.
2Ease of manufacture
If biomass is dried below fiber saturation point to enable comminution, then comminution processing is enabled, but energy consumption increases and feedstock recalcitrance increases
Solution Approach 1:
The invention changes the moisture content parameter by performing comminution at or above fiber saturation point rather than requiring dry conditions. This parameter change enables the comminution process to proceed without energy-intensive drying while preventing feedstock recalcitrance, as the cell walls remain accessible for enzymatic processing.
Solution Approach 2:
The invention converts the typically problematic high-moisture state of biomass (which usually prevents efficient comminution) into a beneficial condition for the cutting process. By using counter-rotating discs that effectively cut wet or fresh biomass, the process turns the harm of high moisture into a benefit, eliminating the need for energy-intensive drying while maintaining processing efficiency.
3Manufacturing precision
If conventional comminution is used to break biomass along the grain, then particle size reduction is achieved, but particle shape and flow properties deteriorate
Solution Approach 1:
The counter-rotating discs create asymmetric cutting actions that produce particles with more uniform shapes and improved flow characteristics. The asymmetric motion patterns and cutting angles generated by the counter-rotating configuration create particles that are less elongated and more spherical, improving flow properties while maintaining size uniformity.
Solution Approach 2:
The dynamic counter-rotating motion of the discs creates continuously varying cutting conditions that produce more uniform particle shapes. The dynamic interaction between the rotating discs and feedstock ensures consistent particle formation across the feed stream, improving both shape uniformity and flow properties compared to static or single-direction cutting methods.
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 produces precision feedstock particles with consistent size and shape, improved flowability, and reduced energy consumption, enhancing the efficiency of biomass conversion processes by optimizing particle size and shape for specific end-user requirements.
Implementation Method 1
counter rotating pair of intermeshing arrays of cutting discs
Data Source
AI summary
A process of comminution of corn stover having a grain direction to produce a mixture of corn stover, by feeding the corn stover in a direction of travel substantially randomly to the grain direction one or more times through a counter rotating pair of intermeshing arrays of cutting discs (D) arrayed axially perpendicular to the direction of corn stover travel.