Sizing
| Technology | |
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| Technology details | |
| Name: | Sizing |
| Category: | Pre-processing |
| Feedstock: | straws, wood, wastes |
| Product: | Flowable small-sized biomass |
Sizing is a mechanical process that aims to reduce the particle size and crystallinity and to increase the specific surface area of biowaste to promote further processing of the substrate.[1] This is achieved by eliminating mass and heat transfer limitation during the required reaction. It is a very efficient technique, but a major drawback is the high energy input.[2] Moreover, sizing makes the biomass easier to handle and allows it to flow. Sizing includes chipping, extrusion, grinding, and milling as base technologies.
Feedstock
Origin and composition
Sizing is a pre-treatment technology for nearly all biowaste materials that consist of large particles like straws, wood pieces, plant fibres and other materials. It is needed to prepare smaller particles that can be processed in further steps.
Pre-treatment
Sizing is often performed as a first step in the process and requires no other pre-treatment. It is, however, not uncommon to first perform a coarse grinding before a fine grinding into smaller particles. Moreover, extrusion and milling are commonly combined with another sizing pre-treatment such as grinding.
Process and technologies
Sizing technologies normally are divided into chipping, extrusion, grinding, and milling technologies:
Chipping
For chipping normally a chipper machine is used that consists of sharp cutting knives, that slice bigger parts into smaller chips. This is used e.g. for wood materials, straws, mixed garden residues and other feedstock that can be cut by a knife. Chippers are susceptible to knife wear from high soil content, metal contamination, rocks and stone, so the base feedstock normally needs to be cleaned before chipping. The size of the resulting materials is typically 10–30 mm after chipping.
Extrusion
Extrusion is a continuous process that can handle a wide range of feedstocks, including viscous and complex fluids and powders. The feedstock is heated and forced through an opening called 'die'. The feedstock is forced through the die by one or two screws in a heated barrel, the extruder.[3]
Grinding
There are two types of grinding: coarse grinding, which can then be followed by fine grinding. Normally a grinder is used that cracks bigger parts into smaller particles. The size of the resulting materials is typically 0.2–2 mm. Grinding is achieved by shearing and/or friction and the grinding effect is achieved by multiple comminution in an increasingly narrowing grinding gap, which can usually be varied by axial displacement of a rotor or stator. The frequently tested process variables are screen size, angular velocity, time, feed rate, type, feed size, load, moisture content, and process.[4]
Milling
Milling combines several mechanical stresses, such as compression, friction, impact, and shear. The combination of these stresses reduce the particle size, crystallinity, and degree of polymerisation, making the biowaste more accessible for further processing. However, milling is energy intensive and has a high capital cost. The required energy can be reduced by combining milling with other processes.[5]
Product
Products of sizing processes are chips, small particles or meals that can directly be used for further processing.
Post-treatment
Technology providers
| Company name | Country | Technology category | Technology name | TRL | Capacity [kg/h] | Cooling system available | Feedstock: Food waste | Feedstock: Garden & park waste |
|---|---|---|---|---|---|---|---|---|
| Company 1 | [Country HQ location] | [Technology category (if different sub-categories are defined this has to be specified here, the available categories can be found on each technology page under the chapter Process and technologies)] | [Technology name (the "branded name" or the usual naming from company side)] | [4-9] | [numeric value] | ● | ● | ● |
| Company 2 | [Country HQ location] | [(if different sub-categories are defined this has to be specified here, the available categories can be found on each technology page under the chapter Process and technologies)] | [Technology name (the "branded name" or the usual naming from company side)] | [4-9] | [numeric value] | ● | ● | ● |
Company 1
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| Technology name: | Technology category: | Pre-processing (Physical processes and technologies), Post-processing (Physical processes and technologies) | |
| TRL: | Capacity: | kg·h-1 | |
| Size (feedstock): | (LxWxH) [mm] | Size (product): | (LxWxH) [mm] |
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ANDRITZ
Mastershred GmbH
Open access pilot and demo facility providers
Patents
Currently no patents have been identified.
References
- ↑ Quanguo Zhang, Chao He, Jingzheng Ren, Michael Goodsite, 2021: Waste to renewable biohydrogen. Volume 1, Advances in theory and experiments. Elsevier Inc., Amsterdam.
- ↑ Muhammad H. Rashid, 2015: Electric renewable energy systems. Elsevier Inc., London, UK.
- ↑ Clive Maier, 1998: Polypropylene : the definitive user's guide and databook. Plastics Design Library, Norwich, NY.
- ↑ Tumuluru JS, Heikkila DJ, 2019: Biomass Grinding Process Optimization Using Response Surface Methodology and a Hybrid Genetic Algorithm. Bioengineering, Vol. 12, (6, no. 1), 1-12. doi: https://doi.org/10.3390/bioengineering6010012
- ↑ Yalew Woldeamanuel Sitotaw, Nigus G. Habtu, Abaynesh Yihdego Gebreyohannes, Suzana P. Nunes, Tom Van Gerven, 2021-08-12: Ball milling as an important pretreatment technique in lignocellulose biorefineries: a review. Biomass Conversion and Biorefinery, Vol. , . doi: https://doi.org/10.1007/s13399-021-01800-7