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Difference between revisions of "Densification"
Review and expansion
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{{Infobox technology | {{Infobox technology | ||
| Feedstock = | | Feedstock = All materials | ||
| Product = | | Product =Biomass with increased density (e.g. pellets or briquettes) | ||
|Name=Densification}} | |Name=Densification|Category=Pre-processing}} | ||
<onlyinclude>'''Densification''' | <onlyinclude>'''Densification''' is a mechanical method to compress material with a low density, such as [[garden and park waste]] consisting of small pieces or sawdust, to consistent structures via pressure. Binder agents can be used to increase the cohesion of the particles. Densification overcomes biowaste issues with low densities, a low heating value per unit of volume, high dust levels, and a large variety in physical shapes. The process generally produces pellets or briquettes, which have a lower transportation cost and are easy to handle, which enables industrial processing.<ref name=":0">{{Cite journal|title=Treatment technologies for urban solid biowaste to create value products: a review with focus on low- and middle-income settings|year=2017-03|author=Christian Riuji Lohri, Stefan Diener, Imanol Zabaleta, Adeline Mertenat, Christian Zurbrügg|journal=Reviews in Environmental Science and Bio/Technology|volume=16|issue=1|page=81–130|doi=10.1007/s11157-017-9422-5}}</ref> [[Pyrolysis]] and [[torrefaction]] can also be seen as forms of densification.</onlyinclude> | ||
==Feedstock== | ==Feedstock== | ||
=== Origin and composition === | === Origin and composition === | ||
Densification is used to pre-treat biomass or other materials | Densification is used to pre-treat biomass or other materials such as wood or straw that consists of very small pieces or dust to make it available for processing or combustion. It can also be used as intermediate or final step in a process chain. Compressed compounds can contain various organic materials, including wood, straw, rice husk, bagasse, ground nut shells, municipal solid waste, agricultural waste and others. | ||
=== Pre-treatment === | === Pre-treatment === | ||
A densification commonly includes a drying step and a [[Sizing|grinding]] step before the material is pressed into pellets or briquettes. Both the drying and grinding pre-treatment are often seen as part of the densification process and therefore no additional pre-treatment is required. The biomass can be pre-heated to increase the stability and density of the pellets or briquettes.<ref name=":0" /> | |||
== Process and technologies == | == Process and technologies == | ||
For the densification process the biomass raw materials are | For the densification process the biomass raw materials are dried and [[Sizing|ground]]. Next, the material is densified into pellets or briquettes via a pressure step. The product is then cooled, screened and bagged. For the densification step there are three main types of processes: extrusion, pelletising, and roll briquetting. In an extrusion process, the material is pushed through a screw or a piston to create small cylindrical shapes. In the pelletising process, the material is is forced through the holes of a perforated cylinder. Finally, for roll briquetting, the material falls between two rollers that rotate in opposite direction to create briquettes.<ref name=":0" /> | ||
==Product== | ==Product== | ||
[[File:Wood pellets-small huddle PNr°0108.jpg|thumb|Pellets made of wood]] | [[File:Wood pellets-small huddle PNr°0108.jpg|thumb|Pellets made of wood]] | ||
Densification is a pre-treatment process that make biomass dust or small pieces more suitable for following processes. It also is used to compress final products like powdered charcoal to produce pellets or briquettes for burning. | The material will leave the densification step as pellets or briquettes. Briquettes are larger and can be made from biomass with larger particles and a higher moisture content without adding a binding agent.<ref name=":0" /> Densification is a pre-treatment process that make biomass dust or small pieces more suitable for following processes. It also is used to compress final products like powdered charcoal to produce pellets or briquettes for burning. The most common application of the product is for domestic heating or industrial fuel. | ||
=== Post-treatment === | === Post-treatment === | ||
During the process heat is generated from the friction. Therefore, the pellets or briquettes are cooled after densification. No further post-processing is required, however, the product is often screened and bagged.<ref name=":0" /> | |||
==Technology providers== | ==Technology providers== | ||