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Difference between revisions of "Sizing"
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=== Origin and composition === | === Origin and composition === | ||
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. | 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 === | === 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 | 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== | == Process and technologies== | ||
Sizing technologies normally are divided into chipping | Sizing technologies normally are divided into chipping, extrusion, grinding, and milling 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 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. | 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.<ref>{{Cite book|author=Clive Maier|year=1998|book_title=Polypropylene : the definitive user's guide and databook|publisher=Plastics Design Library|place=Norwich, NY|ISBN=978-0-8155-1867-9}}</ref> | |||
=== Grinding === | === 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.<ref>{{Cite journal|author=Tumuluru JS, Heikkila DJ|year=2019|title=Biomass Grinding Process Optimization Using Response Surface Methodology and a Hybrid Genetic Algorithm|journal=Bioengineering|volume=12|issue=6, no. 1|page=1-12|doi=10.3390/bioengineering6010012}}</ref> | |||
=== 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.<ref>{{Cite journal|title=Ball milling as an important pretreatment technique in lignocellulose biorefineries: a review|year=2021-08-12|author=Yalew Woldeamanuel Sitotaw, Nigus G. Habtu, Abaynesh Yihdego Gebreyohannes, Suzana P. Nunes, Tom Van Gerven|journal=Biomass Conversion and Biorefinery|doi=10.1007/s13399-021-01800-7}}</ref> | |||
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== Product == | == Product == | ||
Products of sizing processes are chips, small particles or meals that can be | Products of sizing processes are chips, small particles or meals that can directly be used for further processing. | ||
=== Post-treatment === | === Post-treatment === | ||
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=== Mastershred GmbH === | === Mastershred GmbH === | ||
== Open access pilot and demo facility providers == | == Open access pilot and demo facility providers == | ||
[https://biopilots4u.eu/database?field_technology_area_data_target_id=107&field_technology_area_target_id%5B88%5D=88&field_contact_address_value_country_code=All&field_scale_value=All&combine=&combine_1= Pilots4U Database] | [https://biopilots4u.eu/database?field_technology_area_data_target_id=107&field_technology_area_target_id%5B88%5D=88&field_contact_address_value_country_code=All&field_scale_value=All&combine=&combine_1= Pilots4U Database] | ||