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Pyrolysis: Difference between revisions
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<ref name="ref2">[https://www.researchgate.net/publication/330335978_Design_of_A_Fluidized_Bed_Reactor_For_Biomass_Pyrolysis Design of A Fluidized Bed Reactor For Biomass Pyrolysis]</ref> | <ref name="ref2">[https://www.researchgate.net/publication/330335978_Design_of_A_Fluidized_Bed_Reactor_For_Biomass_Pyrolysis Design of A Fluidized Bed Reactor For Biomass Pyrolysis]</ref> | ||
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=== Vacuum Furnace Reactor === | |||
[[File:Schematic for a Vacuum Pyrolysis Reactor.png|250px|right|Schematic for a vacuum pyrolysis reactor. All rights reserved.]] | |||
For a vacuum furnace reactor, the biomass is thermally decomposed under reduced pressure. This produces vapours which are quickly removed from the vacuum and recovered as bio-oil via condensation. This reactor has the ability to produce larger particles than most fast pyrolysis reactors and there is less tar in the bio-oil product due to lower gas velocities. The typical liquid yields for dry biomass feed produced from vacuum furnace reactors range from 35% to 50%. | |||
<ref>[https://www.researchgate.net/publication/333827218_Liquefaction_of_Biomass_and_Upgrading_of_Bio-Oil_A_Review Liquefaction of Biomass and Upgrading of Bio-Oil]</ref> | |||
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=== Ablative Reactor === | |||
[[File:Ablative Pyrolyser.png|250px|right|Ablative pyrolysis reactor. All rights reserved.]] | |||
The ablative reactor provides high relative motion between the reactor wall and the particles in the presence of high pressure exerted by the particles of the hot reactor wall. The system is intensive and the process is mechanically driven so the reactor is complex. This type of reactor has advantages over fluidised bed: | |||
*No pre-treatment/sorting of the biomass is required because it is in direct contact with the hot surface so is not influenced by particle size | |||
*They have good heat transfer with high heating rates and relatively small contact surface because their compact design | |||
*They have high energy and cost efficiency as no heating and cooling of fluidizing gases is required | |||
*They allow installation of condensation units with a small volume, requiring less space at lower costs | |||
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=== Rotating Cone Reactor === | |||
[[File:Rotating Cone Pyrolysis Reactor.png|250px|right|Rotating cone pyrolysis reactor. All rights reserved.]] | |||
The rotating cone reactor is a novel type for flash pyrolysis. It is characterised by rapid heating, a short residence time for solids and negligible char formation. Biomass materials (wood, rice husks, olive stones) are pulverised and fed into the rotating cone pyrolyzer. There is also a riser for sand recycling and a bubbling char combustor for char burn off in which carrier gas is required. Relatively fine particles are needed to produce good liquid yields of 60% to 70% of dry feed. However, this type of reactor is still at pilot scale as there is no commercial applications as of yet. | |||
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=== Auger Reactor === | |||
[[File:Diagram of an auger pyrolysis reactor.png|250px|right|Diagram of an auger pyrolysis reactor. All rights reserved.]] | |||
In an auger reactor, hot sand and biomass particles enter at one end of a screw. The screw mixes these inputs and conveys them along, providing good control of the biomass residence time. The process does not dilute the pyrolysis products with the carrier or fluidising gas, but the sand must be reheated in a separate vessel. Mechanical reliability is a concern and so there is currently no large-scale implementation of this reactor type. Advantages of this reactor: | |||
*Compact size | |||
*No carrier gas required | |||
*Lower operating temperature (400°C) <ref name="ref1" /> | |||
<ref>[https://www.researchgate.net/publication/272494234_Effect_of_Temperature_on_Product_Yield_from_the_Pyrolysis_of_Soybean_Cake_in_an_Auger_Reactor Effect of Temperature on Product Yield from the Pyrolysis of Soybean Cake in an Auger Reactor]</ref> | |||