Composition-Preserving Extraction and Characterization of Biomass Extrinsic and Intrinsic Inorganic Compounds

Abstract

The inorganic content of biomass impairs size reduction tool life and the conversion process. Conventional ash extraction relies on furnace combustion that inevitably alters the inorganic compounds due to oxidation and decomposition. This study developed composition-preserving methods for extracting and analyzing extrinsic and intrinsic inorganic compounds. Comprehensive characterization was carried out on selected biomass feedstocks, including corn stover, pine residue, and pine anatomical fractions, to reveal their inorganic species and morphology. The extrinsic inorganic compounds were found to be dominated by quartz, along with other minor minerals, such as albite, microcline, and gehlenite, and have particle sizes ranging from tens to hundreds of micrometers. Among the pine anatomical fractions, the needles contain the highest intrinsic silicon content while the bark trapped the most extrinsic minerals. By correlation of the total ash and extrinsic inorganic contents to the wear behavior, both the extrinsic and intrinsic inorganic compounds were concluded to have made significant contributions to the wear process. The results here validated a new approach to characterize inorganic compounds in biomass and provided fundamental insights for their potential impact on preprocessing tool wear.

Wear Mechanism Analysis of a New Rotary Shear Biomass Comminution System

“…The wood chip sizes before and after rotary shear processing are 30 × 30 × 10 and 15 × 10 × 6 mm 3 , respectively. The wood chips were first dried, and the EIPs were then extracted from 1 kg of each feedstock sample using a composition-preserving extraction method developed earlier . The weight percentages were measured to determine the content of EIPs for 1 kg of the woodchips before and after comminution.…”

“…Biomass inorganic content (often called “ash”) − has been found to be largely responsible for the processing tool wear. ,− There is intrinsic inorganic content inside the plant cells and tissues as a result of normal physiological processes and extrinsic inorganic particles (EIPs), typically soil or dust contamination either adhered to the biomass surface or collected during harvest. The abrasiveness of the biomass feedstock depends on the concentration, chemical composition, and particle size and shape of the inorganic compounds. − EIPs were reported with high hardness of 6.5–7.5 Mohs. , Detailed characterizations of the inorganic compounds of corn stover and pine residue have been conducted recently . The wear of the hammer mill was investigated, and erosion was determined to be the dominant wear mode as a result of high-speed impact with the biomass inorganic compounds .…”

Identification of Critical Process Parameters for Knife Milling and Alternative Communication Strategies

“…Task 1 currently focuses on issues related to wear and durability of components used in unit operations to pretreat feedstocks arriving from the field/forest to the entrance of biochemical or thermal reactors where the feedstocks are converted into useful products. Studies [6,7] have shown that mechanical wear can be significant, with wear clearly visible to the naked eye. The wear can add significant delays in processing feedstocks due to high downtimes to replace worn components, but also to clear jams that occur in milling units.…”

An Abrasive Wear Model of Knife Milling to Predict the Impact of Material Properties and Milling Parameters on Knife Edge Recession

“…These operations include bale processing (deconstruction/shredding of corn stover bound up into square/rectangular or round bales weighing approximately ½ ton) and size-reduction operations to yield loose, free flowing biomass that can be readily treated by downstream pretreatment and conversion/digestion processes. Additional processing steps are often used to remove rock, gravel, sand and nonferrous metallic contaminants and to classify/separate the biomass by size and anatomical fractions prior to size reduction operations [6]. Figure 1 illustrates the flow diagram of major preprocessing operations used in the comminution of biomass feedstock.…”