Year-Round Storage Operation of Three Major Agricultural Crop Residue Biomasses by Performing Dry Acid Pretreatment at Regional Collection Depots

Abstract

Commercial cellulosic biofuel operation requires a reliable, low-cost, and stable feedstock logistic system. One great challenge is its long-term storage at least for one harvest cycle (1 year for agricultural crop residues) with a minimum loss of bulky, geographically dispersed, inflammable, and easily degradable lignocellulosic biomass. This study conducted an investigation of year-round storage of the agricultural crop residue feedstock under the scenario of performing dry acid pretreatment at the distributed regional collection depots, instead of the central biorefinery plant. The dry acid pretreatment method provides a practical basis for the storage operation by its ability for high preservation of polysaccharide solids, highly compacted accumulation density, being free from wastewater generation, low capital investment, and low energy consumption. Three major agricultural crop residues (corn stover, wheat straw, and rice straw) were pretreated by dry acid pretreatment and then stored in their major planting regions under varying natural conditions of temperature, rain and snow fall, humidity, wind, and sunlight. The pretreated corn stover, wheat straw, and rice straw contained approximately 50% (w/w) of moisture, and their high water absorption capacity maintained the crop residues in solid and fine-particle forms without free wastewater generation and flammability. Meanwhile, the pretreated crop residues were of low pH value and contained various inhibitory compounds for microbial growth. The results show that the crop residue feedstocks were well preserved with negligible solid and fermentable sugar loss after year-round storage in different regions. The physical properties, chemical compositions, enzymatic hydrolysis yields, and ethanol fermentability were maintained essentially constant with a few positive exceptions such as the increased hydrolysis yield and reduced inhibitor content. A case study shows that the feedstock transportation cost of the long-term stored feedstocks under the scenario of dry acid pretreatment at collection depots was significantly reduced compared to that of the direct transportation of virgin crop residual feedstocks. This study provided an efficient and practical logistic system for large-scale biorefinery plants.

Changes in pH Values Allow for a Visible Detection of the End Point in Submerged Liquid Biodetoxification during Biorefinery Processing

“…Submerged liquid biodetoxification offers several advantages over solid-state biodetoxification due to the liquid method’s inherent properties and compatibility with the existing biorefinery chain. The pretreated lignocellulose feedstock can be hydrolyzed directly into high solids loading slurry, resulting in an increase in density from approximately 380 to around 1030 kg/m 3 and the equipment cost is reduced correspondingly. , The improved heat and mass transfer in the liquid slurry enable efficient mixing, cell growth, and inhibitor metabolism, resulting in reduced electricity consumption and shorter biodetoxification times compared to solid-state biodetoxification. Submerged liquid biodetoxification of typical dry acid pretreated lignocellulosic feedstock by P. variotii FN89 can be completed within 18.0 h under moderate aeration (1.0 vvm) with minimal loss of fermentable sugars (approximately 1–2%).…”

Targeted Functionalization of Waste Lignocellulosic Biomass to Produce Sound Absorbing Materials

“…The transformation of agricultural residues such as rice straw to bio-based materials requires a pretreatment step due to the recalcitrance nature of biomass [21][22][23]. Mechanical, chemical, physicochemical, and biological pretreatment techniques are employed [21,[24][25][26][27][28][29][30][31][32], out of which chemical pretreatment is considered most effective in the deligni cation of biomass [33]. However, large-scale use of toxic chemicals in pretreatment processes necessitates an environmentally benign process [34,35].…”