Difference between revisions of "Ammonia fibre expansion"
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Ammonia fiber expansion (AFEX) is a thermochemical pretreatment that uses volatile ammonia as the main reactant for cellulosic biomass pretreatment. AFEX pretreatment increases the accessibility of polysaccharides to enzymes for hydrolysis into fermentable sugars. These released sugars can be converted into fuels and chemicals in a biorefinery. AFEX offers several advantages over other pretreatments, which include near complete recovery of the pretreatment chemical (ammonia), nutrient addition for microbial growth through the remaining ammonia on pretreated biomass, and not requiring a washing step during the process which facilitates high solid loading hydrolysis. | |||
== Feedstock == | == Feedstock == | ||
=== Origin and composition === | === Origin and composition === | ||
Agricultural residues and energy crops | |||
== Process and technologies == | == Process and technologies == | ||
=== Process === | === Process === | ||
During AFEX pretreatment, liquid ammonia is added to the biomass under moderate pressure (100 to 400 psi) and temperature (70 to 200°C) before rapidly releasing the pressure. Major process parameters are the temperature of the reaction, residence time, ammonia loading, and water loading. The process decrystallises the cellulose, hydrolyses hemicellulose, removes and depolymerises lignin, and increases the size and number of micropores in the cell wall. As a result, the rate of enzymatic hydrolysis increases significantly.<ref>{{Cite journal|author=Mosier N., Wyman C., Dale BE., Elander R., Lee YY., Holtzappel M., Ladisch M.|year=2005|title=Features of promising technologies for pretreatment of lignocellulosic biomass|journal=Bioresource Technology|volume=96|page=673-686}}</ref> | |||
=== Technologies === | === Technologies === | ||
Revision as of 09:01, 23 September 2021
Ammonia fiber expansion (AFEX) is a thermochemical pretreatment that uses volatile ammonia as the main reactant for cellulosic biomass pretreatment. AFEX pretreatment increases the accessibility of polysaccharides to enzymes for hydrolysis into fermentable sugars. These released sugars can be converted into fuels and chemicals in a biorefinery. AFEX offers several advantages over other pretreatments, which include near complete recovery of the pretreatment chemical (ammonia), nutrient addition for microbial growth through the remaining ammonia on pretreated biomass, and not requiring a washing step during the process which facilitates high solid loading hydrolysis.
Feedstock
Origin and composition
Agricultural residues and energy crops
Process and technologies
Process
During AFEX pretreatment, liquid ammonia is added to the biomass under moderate pressure (100 to 400 psi) and temperature (70 to 200°C) before rapidly releasing the pressure. Major process parameters are the temperature of the reaction, residence time, ammonia loading, and water loading. The process decrystallises the cellulose, hydrolyses hemicellulose, removes and depolymerises lignin, and increases the size and number of micropores in the cell wall. As a result, the rate of enzymatic hydrolysis increases significantly.[1]
Technologies
Product
Technology providers
- ↑ Mosier N., Wyman C., Dale BE., Elander R., Lee YY., Holtzappel M., Ladisch M., 2005: Features of promising technologies for pretreatment of lignocellulosic biomass. Bioresource Technology, Vol. 96, 673-686. doi: https://doi.org/