Herbaceous Feedstock 2021 State of Technology Report

Abstract

The U.S. Department of Energy (DOE) promotes the production of advanced liquid transportation fuels from lignocellulosic biomass by funding fundamental and applied research that advances the State of Technology (SOT). As part of its involvement with this mission, Idaho National Laboratory (INL) completes an annual SOT report for biomass feedstock logistics. This report summarizes supply system impacts of Bioenergy Technologies Office (BETO)-funded research and development efforts at INL and INL collaboration with external partners (e.g. Forest Concepts, Purdue University ) that lead to improvements in feedstock supply systems. These include improvements to and observed performance of innovative harvest and collection methods, storage technologies, transportation and handling approaches, and advanced preprocessing technologies. Biomass quality and variability, and the interface between feedstock quality and conversion performance are key drivers in addition to delivered feedstock cost. In this report, we estimate the benefits of R&D technology improvements to individual supply system unit operations and present the status of feedstock logistics technology development for converting herbaceous biomass into biofuels. These analyses are supported by experimental data where possible and help to align the SOT relative to the cost goals defined in the Multi-Year Plan. The 2021 Herbaceous SOT incorporates an advanced biomass fractionation system for separating anatomical fractions (e.g. leaf, stem, husk, and cob) of delivered corn stover, thus, to maximize the goal of reducing extrinsic ash and improving carbohydrate content in the pre-processed biomass. The air classification in the fractionation system is supported by a Spudnik Air separator, which is a large-scale equipment that can efficiently remove soil contaminant (about 25%) and separate high ash content tissue such as leaf and husks. By eliminating extrinsic ash in biomass and the high ash content fractions, we have reduced ash content of three-pass corn stover from 11.20% to 6.00%, and increased carbohydrate content from 56.80% to 60.16%. This technical improvement has allowed us to eliminate two-pass corn stover from the biomass supply curve, therefore largely reduced the harvesting and collection cost, and transportation costs within the feedstock logistics system. In addition, the second stage hammer mill was replaced with rotary shear, which is less sensitive to moisture content than hammer milling and has higher throughput with lower energy consumption. The reduced energy consumption has also contributed to the modeled cost reduction. The 2021 nth-plant Herbaceous SOT predicts a modeled delivered feedstock cost of $78.21/dry ton (2016$), this is a $0.54/dry ton (2016$) decrease from the 2020 Herbaceous SOT nth-Supply case cost. Technology improvements that contributed to this modeled cost reduction include reduced cost in the feedstock harvesting, collection and transportation cost caused by eliminating two-pass corn stover, and reduced energy consumption cost by replacing the hammer mill with rotary shear. A preliminary greenhouse gas emissions (GHG) assessment was completed by scaling the 2020 Herbaceous nth-plant GHG data from the 2020 Greenhouse Gases, Regulated Emissions, and Energy use in Transportation model (GREET) , shows a decrease of 9.77 kg CO2e/ton from the 2020 SOT (77.48 kg CO2e/ton in the 2020 Herbaceous Feedstock SOT to 67.71 kg CO2e/ton in the 2020 Herbaceous Feedstock SOT). This net reduction is attributed to reduced transportation distances for biomass delivery from field to depot, and reduced energy consumption by using rotary shear, and will be updated once Argonne National Laboratory has completed their Supply Chain Sustainability Analysis for the 2021 SOTs. In the 1st-plant analysis of the 2021 Herbaceous SOT system, the average throughput was 2,044 dry tons/day or 92.7% of the name plate capacity. During the simulation the daily throughput ranged from 848.1 dry tons/day to 2,338 dry tons/day, which equates to 38.5% to 106% of the daily nameplate capacity. After the year of operation 715,400 tons (98.33% of the annual nameplate capacity) of preprocessed feedstock were produced; the variability in throughput was primarily caused by equipment failures in the system. Failures due to wear were the largest cause of disruption within the system, accounting for 70.04% of the failures and 91.28% of the total downtime. Previously, moisture related failures were the cause of the majority of downtime, but new storage strategies and equipment (bale dryer for the first 25% of stover harvested) data from the Biomass Storage project (WBS 1.2.1.1) led to the elimination of moisture related downtime. Ultimately the system on-stream time was 87.65% during the simulation period. Considering the operational delays and material losses in the system, the average cost per ton of biomass was $82.34/dry ton, with a range from $72.24/dr