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Difference between revisions of "Sizing"
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| Product =Flowable small-sized biomass | | Product =Flowable small-sized biomass | ||
|Name= Sizing|Category=Pre-processing}} | |Name= Sizing|Category=Pre-processing}} | ||
<onlyinclude>'''Sizing''' | <onlyinclude>'''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.<ref>{{Cite book|author=Quanguo Zhang, Chao He, Jingzheng Ren, Michael Goodsite|year=2021|book_title=Waste to renewable biohydrogen. Volume 1, Advances in theory and experiments|publisher=Elsevier Inc.|place=Amsterdam|ISBN=978-0-12-821659-0}}</ref> 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.<ref>{{Cite book|author=Muhammad H. Rashid|year=2015|book_title=Electric renewable energy systems|publisher=Elsevier Inc.|place=London, UK|ISBN=978-0-12-800636-8}}</ref> Moreover, sizing makes the biomass easier to handle and allows it to flow. Sizing includes chipping, extrusion, grinding, and milling as base technologies. </onlyinclude> | ||
== Feedstock == | == Feedstock == | ||
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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 further grinding the biomass into smaller particles. | 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 further grinding the biomass into smaller particles. | ||
== Process and technologies | == Process and technologies== | ||
Sizing technologies normally are divided into chipping or grinding technologies: | Sizing technologies normally are divided into chipping or grinding technologies: | ||
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=== Chipping === | === 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. | 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. | ||
=== Grinding === | |||
For grinding normally a grinder is used that cracks bigger parts into smaller particles. 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 size of the resulting materials is typically 0.2–2 mm after milling or grinding. | |||
There are two types | |||
of grinding: coarse grinding and fine grinding. The raw biomass that is harvested from forests or fields goes through a coarse grinding process. This coarsely ground biomass is further ground to a fine size for various applications.The frequently tested process variables are screen size, angular velocity, time, feed rate, type, feed size, load, moisture content, and process. (<nowiki>https://www.mdpi.com/2306-5354/6/1/12/htm</nowiki>) | |||
of grinding: coarse grinding and fine grinding. The raw biomass that is harvested from forests or | |||
fields goes through a coarse grinding process. This coarsely ground biomass is further ground to | |||
a fine size for various applications.The frequently tested | |||
process variables are screen size, angular velocity, time, feed rate, type, feed size, load, moisture content, | |||
and process. (https://www.mdpi.com/2306-5354/6/1/12/htm) | |||
=== Extrusion === | === Extrusion === | ||