Pellets From Pretreated Biomass
- Type: Conference Presentation
- Conference Type: AIChE Annual Meeting
- Presentation Date: October 16, 2011
- Duration: 30 minutes
- Skill Level: Intermediate
- PDHs: 0.50
Kinetic data show that hemicelluloses and water extractives react very quickly compared to cellulose and that lignin is relatively inert, resulting in a biochar with increased lignin content. Lignin extracted from raw wood by Van-Soest method exhibits a glass transition temperature at about 135-165 ˚C. Similarly, lignin extracted from HTC biochar exhibits a glass transition temperature in the same range. Lignin acts as a natural binder for pelletization of HTC biochar, if pelletizing is done in the temperature range of glass transition. A hydraulic press with a controllable heated die was used for producing uniform pellets. The materials used to make pellets were raw loblolly pine and pine pretreated at 200°C, 230°C, and 260°C. The sample was compressed into a 13 mm die to make cylindrical pellets 8-10 mm long. The pressure applied was 1000 MPa while a temperature of 140 ˚C was maintained for 30 seconds to allow the lignin showing the glass transition behavior.
Pellets made from HTC biochar exhibit favorable properties resulting from high levels of lignin, including increased abrasion resistance, increased durability, increased modulus of elasticity, increased energy density, and increased mass density. On the other hand, ultimate breaking strength of pellets is decreased with increasing pretreatment temperature. Pellets produced from biomass pretreated at 260°C, have volumetric fuel value 70% greater than pellets produced from untreated pine and 142% greater than the raw biomass. Equilibrium moisture content (EMC) of pellets of HTC biochar pretreated at 260 ˚C is about one fourth that of pellets produced from raw biomass. Pellets produced from HTC biochar maintain structural integrity significantly longer than do pellets produced from raw woody biomass.
|AIChE Member Credits||0.5|
|AIChE Graduate Student Members||Free|
|AIChE Undergraduate Student Members||Free|