Final Report: DOE/ID/14215
The proposed straw separation system developed in the research project harvests the large internode sections of the straw which has the greater potential as a feedstock for lignocellulosic ethanol production while leaving the chaff and nodes in the field. This strategy ensures sustainable agriculture by preventing the depletion of soil minerals, and it restores organic matter to the soil in amounts and particle sizes that accommodate farmers’ needs to keep tillage and fertilizer costs low. A ton of these nutrient-rich plant tissues contains as much as $10.55 worth of fertilizer (economic and energy benefits), in terms of nitrogen, phosphorus, potassium, and other nutrients provided to the soil when incorporated by tillage instead of being burned. Biomass conversion to fermentable sugars for the purpose of producing fuels, chemicals, and other industrial products is well understood. Most bioenergy strategies rely on low-cost fermentable sugars for sustainability and economic viability in the marketplace. Exploitation of the “whole crop”—specifically, wheat straw or other plant material currently regarded as residue or waste—is a practical approach for obtaining a reliable and low-cost source of sugars. However, industrial-scale production of sugars from wheat straw, while technically feasible, is plagued by obstacles related to capital costs, energy consumption, waste streams, production logistics, and the quality of the biomass feedstock. Currently available separation options with combine harvesters are not able to achieve sufficient separation of the straw/stover and chaff streams to realize the full potential of selective harvest. Since ethanol yield is a function of feedstock structural carbohydrate content, biomass anatomical fractions of higher product yield can have a significant beneficial impact on minimum ethanol selling price. To address this advanced biomass separation computation engineering models were developed to more effectively and efficiently engineer high-fidelity and high throughput separation systems for biomass components. INL and Iowa State University developed a computational modeling strategy for simulating multi-phase flow with an integrated solver using various computational fluid dynamics (CFD) codes. ISU set up a classic multi-phase test problem to be solved by the various CFD codes. The benchmark case was based on experimental data for bubble gas holdup and bed expansion for a gas/solid fluidized bed. Preliminary fluidization experiments identified some unexpected fluidization behavior, where rather than the bed uniformly fluidizing, a “blow out” would occur where a hole would open up in the bed through which the air would preferentially flow, resulting in erratic fluidization. To improve understanding of this phenomena and aid in building a design tool, improved computational tools were developed. The virtual engineering techniques developed were tested and utilized to design a separation baffle in a CNH combine. A computational engineering approach involving modeling, analysis, and simulation was used in the form of virtual engineering to design a baffle separator capable of accomplishing the high-fidelity residue separation established by the performance targets. Through the use of the virtual engineering model, baffle designs were simulated to (1) determine the effect of the baffle on the airflow of the combine cleaning system, and (2) predict the effectiveness of the baffle in separating the residue streams. A baffle design was selected based on the virtual engineering modeling, built into the INL selective harvest test combine. The result of the baffle changes improved the crop separation capability of the combine, enabling downstream improvement in composition and theoretical ethanol yield. In addition, the positive results from the application of the virtual engineering tools to the CNH combine design resulted in further application of these tools to other INL areas of research. INL and the University of Idaho identified, characterized, and modified a key plant biosynthetic lignin gene, cinnamoyl CoA reductase (CCR), to assess its influence on the efficiency with which the resulting biomaterials interact with and are processed by engineering systems. The characterization of CCR genes and resulting antisense gene constructs enabled the modification and assessment of the impact of cell wall biosynthetic gene in wheat. This allows the model systems needed to study the structural and functional post-harvest properties of straw to be created and assessed. Progress was made toward identifying and using key CCR lignin biosynthesis gene sequences for controlling lignin biosynthesis with the goal of altering lignin content and composition in wheat. This was important because of the potential impact that reduced lignin could have on feedstock harvesting, transportation, storage, pretreatment, and processing.
- Research Organization:
- Iowa State Univ., Ames, IA (United States)
- Sponsoring Organization:
- USDOE Office of Industrial Technologies (OIT) - (EE-20)
- DOE Contract Number:
- FC36-01ID14215
- OSTI ID:
- 935984
- Report Number(s):
- DOE/ID/14215; TRN: US200902%%226
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
42 ENGINEERING
BIOMASS
CAPITALIZED COST
CELL WALL
COMPUTERIZED SIMULATION
ENERGY CONSUMPTION
ETHANOL
FLUID MECHANICS
FLUIDIZATION
FLUIDIZED BEDS
LIGNIN
ORGANIC MATTER
OXIDOREDUCTASES
PARTICLE SIZE
PLANT TISSUES
PRODUCTION
SACCHARIDES
STRAW
WHEAT
Biomass Conversion
single pass harvesting
multiphase flow
virtual engineering
lignin synthesis
hydrolysis conversion