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Difference between revisions of "Sizing"
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|Name= Sizing}} | |Name= Sizing}} | ||
<onlyinclude>'''Sizing''' is a mechanical process to change the size of a material to use it in a conversion process. This normally means that a base feedstock with bigger parts is reduced to smaller pieces. Sizing includes chipping and grinding as base technologies.</onlyinclude> | <onlyinclude>'''Sizing''' is a mechanical process to change the size of a material to use it in a conversion process. This normally means that a base feedstock with bigger parts is reduced to smaller pieces. Sizing includes chipping and grinding as base technologies.<!-- Sizing is a mechanical process that aims to reduce the particle size and crystallinity and increase the specific surface area of biomass to promote the degradation of substrate. (Stanislaus et al., 2018) This to eliminate mass and heat transfer limitation during the required reaction. It is a very efficient technique, but a major drawback is the high energy input. (Moodley P., Trois C., 2021) --></onlyinclude> | ||
== Feedstock == | == Feedstock == | ||
=== Origin and composition === | === Origin and composition === | ||
Sizing is a pre-treatment technology for nearly all materials that consist of | Sizing is a pre-treatment technology for nearly all 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 === | === Pre-treatment === | ||
== Process and technologies == | == Process and technologies<!-- Milling, grinding, chipping and extrusion -->== | ||
Sizing technologies normally are devided into chipping or grinding technologies: | Sizing technologies normally are devided into chipping or grinding technologies: | ||
=== 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 cutted 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 cutted 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 === | === 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. | 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. (Jaya Shankar Tumuluru 1,* and Dean J. Heikkila, 2019) --> | |||
== Product == | == Product == | ||