Physical characteristics of AFEX-pretreated and densified switchgrass, prairie cord grass, and corn stover

Abstract

LignocellulosicPellet durability Storage a b s t r a c tThe goal of the study was to evaluate and compare the physical properties of control, pretreated and densified corn stover, switchgrass, and prairie cord grass samples.Ammonia Fiber Expansion (AFEX) pretreated switchgrass, corn stover, and prairie cord grass samples were densified by using the comPAKco device developed by Federal Machine Company of Fargo, ND. The densified biomass were referred as "PAKs" in this study. All feedstocks were ground into three different grind size of 2, 4 and 8 mm prior to AFEX pretreatment and the impact of grinding on pellet properties was studied. The results showed that the physical properties of AFEX-PAKed material were not influenced by the initial grind size of the feedstocks. The bulk density of the AFEX-PAKed biomass increased by 1.2e6 fold as compared to untreated and AFEX-pretreated materials. The durability of the AFEX-PAKed materials were between 78.25 and 95.2%, indicating that the AFEX-PAKed biomass can be transported easily. To understand the effect of storage on the physical properties of these materials, samples were stored in the ambient condition (20 ± 2 C and 70 ± 5% relative humidity) for six months. After storage, thermal properties of the biomass did not change but glass transition temperature decreased. The water absorption index and water solubility index of AFEX-treated and AFEX-PAKed biomass showed mixed trends after storage. Moisture content decreased and durability increased upon storage. ScienceDirect ht tp://www.elsevier.com/locate/biombioe b i o m a s s a n d b i o e n e r g y 7 8 ( 2 0 1 5 ) 1 6 4 e1 7 4 http://dx.

Effect of Deep Drying and Torrefaction Temperature on Proximate, Ultimate Composition, and Heating Value of 2-mm Lodgepole Pine (Pinus contorta) Grind

“…These improvements will make biomass meet the specifications in terms of density, particle size, ash composition, and carbohydrate content for both biochemical and thermochemical conversion applications. Various thermal methods, such as dry and wet torrefaction (hydrothermal carbonization) and steam explosion, as well as chemical pretreatment techniques, such as ionic, acid, alkali, and ammonia fiber expansion, were investigated to understand how they improve the biomass specifications for biofuels production [8,9,10,11,12,13]. Recent studies by Sarkar et al .…”

Effect of Ammonia Fiber Expansion Combined with NaOH Pretreatment on the Resource Efficiency of Herbaceous and Woody Lignocellulosic Biomass

“…The AFEX during A-NaOH pretreatment did not have a large effect on the lignin removal rate, but it could redistribute the lignin on the cell wall and form a highly porous structure, thus improving the enzymatic efficiency of lignocellulose. 33 Additionally, AFEX reduces the adverse effect of lignin on cellulase. 34 This alkaline treatment exposes more lignin; since the lignin removal rate affects the enzymatic efficiency, the poor lignin removal rate will adversely affect the enzymatic digestion of lignin.…”

Microbial Heat and Organic Matter Loss in an Aerobic Corn Stover Storage Reactor: A Model Validation and Prediction Approach Using Lumped-Parameter Dynamical Formulation

“…Thermal conductivity governs the rate of heat dissipation in the corn stover storage (Karki et al, 2015). Heat transport by conduction was experimentally performed with a feedback loop through a water jacket in the corn stover storage reactor, as described in section "Corn Stover Storage Reactor Experiments" Conductive heat transfer (Q k ) is modeled as a function of the thermal conductivity (K), the characteristic length (L), the heat flux area (A), and the net temperature difference between the corn stover and water jacket (T 2 − T 1 ) following Eq.…”

“…Corn stover density at sieve materials sizes of 2 mm, 4 mm, and 8 mm are reported at 942, 954, and 832 kg.m −3 , respectively (Karki et al, 2015). The uncertainty of density is assumed negligible in the model.…”