Progress 04/15/24 to 04/14/25

Outputs
Target Audience: Cotton farmers/producers Cotton gins Commodity boards Original equipment manufacturers and vendors Feedstock supply system operators Educators/academicians/researchers Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?One research scientist, one post-doctoral researcher and multiple technicians are being trained in the areas of equipment development, field testing, experimental design, data collection and analysis, and systems-level techno-economic analysis and environmental impact assessment. How have the results been disseminated to communities of interest?Results have been shared among the research team, including PD and co-PDs and staff via direct communication, through presentations in regional and national conferences with wider audiences, and to the allied stakeholders through direct communications. What do you plan to do during the next reporting period to accomplish the goals? Objective 1: Test different equipment configurations for precleaning cotton. Objective 2: Repeat storage studies for small cotton plant modules. Evaluate the pre-cleaning system performance. Objective 3: Conduct pelletization experiments with cotton residues. Objective 4: Finalize techno-economic feasibility analysis and life-cycle environmental impact assessment.

Impacts
What was accomplished under these goals? Objectives 1 and 2: To collect the cotton required for storage and pre-cleaning system performance testing, Phytogen 332 W3FE variety cotton was grown on a drip irrigated field at the USDA ARS Plant Stress Laboratory in Lubbock, TX. The plants harvested for this study were collected from 0.36 acres (8 rows spaced 40 inches apart and about 587 ft long) on November 14 and 15, 2024. Lint yield was approximately 2,006 lb/acre. The plants were cut 1-2 inches above the ground using a sickle bar mower (BFS 210H, Enorossi Agricultural Machinery, Perugia, Italy), and manually gathered and fed into a stationary compacting unit. For storage, 18 micro-modules (2-ft x 2-ft x 4-ft) were formed using cotton plants with the harvest index of 0.44-0.49. Half of the micro modules were formed at the bulk density of ~13 lb/ft3 and the other half were formed at the bulk density of ~16 lb/ft3. The average moisture content of the cotton plants at the time of harvest for all the modules was ~31% (range: 27-37%). Moisture content of the cotton residues was very highat 44-49% because harvest occurred before the killing frost. Moisture content of seed cotton was 8%, which is typical seed cotton harvest moisture. Three modules at each bulk density were opened after 1 week, 2 months and 4 months of storage to evaluate their pre- and post-storage properties. For both high and low bulk density modules, moisture content of seed cotton was 6.5-7.9% at harvest and increased to 16.8-19.4%, 10.5-13.1% after 1 week and 2 months of storage, and decreased to 5.5-8.5% after 4 months of storage. For both high and low bulk densities, moisture content of the residues was 38.5-50.2% at harvest and decreased to 39.1-33.6%, 18.0-22.9% and 7.5-11.0% after 1 week, 2 months and 4 months of storage. No visible signs of degradation were seen post-storage despite the high moisture of the cotton residues at harvest. The material from the modules were separated into seed cotton and residues using the prototype equipment developed. A proof-of-concept prototype machine for separating seed cotton from the cotton plant in stationary setting was developed and tested. Initial evaluation of the system indicated seed cotton recovery rates in excess of 90%. The most critical parameters influencing the performance of the system include 1) cotton boll conformation (open or closed), 2) feeding orientation of cotton stalks (perpendicular or parallel to flow direction), and 3) feeding rate (lb/hr). The system utilizes components that are commonly used and available for cotton harvesters. Additional work is ongoing to reorient the prototype design for multi-stage integration in the post-harvest processing system to produce seed cotton for ginning and cotton residues for bio-product and fuel applications. Objective 3: Using the cotton residues obtained from the modules harvested in 2023, fuel pellets were produced. For pelletization, cotton residues were ground to a particle size of 3 mm and moisture content of the feedstock was adjusted to 30% as it was found to be the most suitable for pelletization based on trial runs. Two die sizes of 6 and 8-mm diameters, representative of typical fuel pellet sizes, were used for forming the pellets. The residues from the high- and low-density modules at each storage duration were pelletized and their pellet characteristics including bulk density, durability and heating value were evaluated. Most of the pellet characteristics were within the standard range set forth by the Pellet Fuel Institute for fuel pellets, except for chlorine content. High chlorine content can cause corrosion of the equipment. However, due to the high ash fusion temperature of the pellets formed (> 1450°C), the degree of corrosiveness would not be as severe. For the material obtained from the modules harvested in 2024, pelletization work is underway. Objective 4: A systems-level techno-economic and environmental-impact assessment model is being developed with the system boundary including all harvesting and post-harvest logistics operations, including storage, cotton plant module cleaning, ginning of seed cotton, and upgrading of the cotton residue and ginning trash through pelletization. The preliminary estimates suggest that by using the proposed system, a net revenue of $22-168/t lint can be earned from the pellets produced after covering the cost of harvest and post-harvest logistics, and processing of cotton residues. Similarly, for environmental impacts in terms of greenhouse gas (GHG) emissions, this system could produce a net benefit of 2.98-3.40 t-CO2eq/t lint considering the use of these fuel pellets in energy applications instead of natural gas. This model will be updated with field and lab obtained data.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Khanal A, Rana B. B, Dhakal S, Wanjura J, and Shah A. Evaluating feasibility of cotton stalks as solid fuel. 2024 CFAES Annual Research Conference, April 9, Columbus, OH. [Poster]

Progress 04/15/23 to 04/14/24

Outputs
Target Audience: Cotton farmers/producers Cotton gins Commodity boards Original equipment manufacturers and vendors Feedstock supply system operators Educators/academicians/researchers Changes/Problems:N/A What opportunities for training and professional development has the project provided?One research scientistand multiple technicians are being trained in the areas of equipment development, field testing, experimental design, data collection and analysis, and systems-level techno-economic analysis. How have the results been disseminated to communities of interest?Results have been shared among the research team, including PD and co-PDs, and staff; through presentations in regional and national conferences with wider audiences; and to the allied stakeholders through direct communications. What do you plan to do during the next reporting period to accomplish the goals?Objective 1: Test different equipment configurations for precleaning cotton. Evaluate the pre-cleaning system performance. Objective 2: Repeat storage studies for small cotton plant modules. Objective 3: Conduct pelletization experiments with the cotton residues and ginning trash. Objective 4: Conduct techno-economic feasibility analysis and life-cycleassessment.

Impacts
What was accomplished under these goals? Objective 1: For the development of the system for pre-cleaning cotton plant bales, the required components have been purchased based on a preliminary design, and the final designs are being evaluated. Once the equipment is configured, different layouts for seed cotton recovery and residue processing will be tested and the most suitable one will be identified. Objective 2: To collect the cotton required for storage trials, Phytogen 332 W3FE variety cotton was grown on a drip irrigated field at the USDA ARS Plant Stress Laboratory in Lubbock, TX. The plants were harvested manually, cutting them manually at ground level, from 0.5 acres (12 rows spaced 40 inches apart and about 525 ft long) on November 16 and 17, 2023. Lint yield was approximately 1740 lb/acre. For storage, 18 micro-modules (2-ft x 2-ft x 4-ft) were formed with the cotton plants, which had a harvest index of 0.30-0.42 (lint and seed to above ground biomass). The seed cotton moisture content at harvest was 9.13-9.94% and that of the cotton residues was 16.25-28.24%. The modules were formed at two bulk densities--11.6 and 15.2 lb/ft3. Six modules, three at each bulk density were opened right after harvest. The moisture content of the seed cotton increased slightly for both high and low bulk density modules to 10-11%. Moisture content of cotton residues was 18-21%, which was more uniform than at harvest. The remaining modules were stored for 2 and 4 months. After 2 months of storage, the seed cotton moisture for the low-density modules (8.42-8.96%) was lower than that for high-density modules (10.33-10.74%). The moisture content of the cotton residues after 2 months of storage was in the range 12-15% for high and low-density modules. The samples collected from 4 months storage trials are still being analyzed. Objective 3: To optimize formulations for upgrading cotton residues to fuel pellets, pellets were formed from residues obtained from the high- and low-density cotton modules, at harvest and after 2 months storage. For pelletization, cotton residues were first ground to a particle size of 3 mm and moisture content of the feedstock was adjusted to 30% as it was found to be the most suitable for pelletization based on trial runs. Two die sizes of 6 and 8-mm diameters, representative of typical fuel pellet sizes, were used for forming the pellets. The residues from the high- and low-density modules at each storage duration were pelletized separately to evaluate the impacts of the cotton module densities on the pellet characteristics. For the pelletization runs that have been completed so far, the bulk density of the pellets was 30-39 lb/ft3, unit density was 65-75 lb/ft3, durability was 95.6-99.1%, and calorific value was 1,816-1,935 kcal/lb. Additional processing of the cotton residue from the cotton plant modules is underway. Objective 4: A systems-level techno-economic model is being developed with the system boundary including all harvesting and post-harvest logistics operations, including storage, cotton plant module cleaning, ginning of seed cotton, and upgrading of the cotton residue and ginning trash through pelletization. The data required for the model is being collected from the literature and field and lab tests.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Khanal, A, and Shah, A. Evaluating the storage characteristics of whole-plant cotton, 2023 ASABE Annual International Meeting, July 8-12, Omaha, NE [Oral]