Christopher Hopkins

Soil phosphorus (P) levels have increased over the past few decades in NC, with less than 10% of soil samples submitted from major swine production counties to NCDA&CS needing P (unpublished data from NCDA&CS). With sludge cleanouts becoming more frequent, the industry is looking for land to receive these materials and alternative strategies for transport out of the production region. Methods of sludge treatment that are of current interest are sludge drying and composting because removal of water is a necessity to increase sludge transport. New sludge drying efforts from the Animal and Poultry Waste Management Center show promise in providing a management option for NC swine producers, and this method creates an organic P product that could be easily shipped to other areas. However, it’s unknown how the drying process affects P availability and how this stacks up to other P fertilizer sources. Therefore, we propose a greenhouse study to further investigate this product in four potential receiving crops.

Swine lagoon sludge management is critical to the operation of swine facilities. Sludge removal from the lagoon is costly and can result in additional cost associated with transportation and land application. In North Carolina, the limited cropping acreage introduces yet another constraint on sludge management. Swine sludge can be processed to generate a dry biomass feedstock that is easier to transport and apply as nutrient source for bioenergy crops and grasses, or as a feedstock for combustion alone or blended with poultry litter, or lignocellulosic feedstock. Sludge removal and drying represent bottlenecks that impede the development of these utilization alternatives. This project will develop and evaluate the performance of sludge removal and drying systems, and characterize the removed, dried sludge as a soil amendment and as a combustion feedstock.

Swine lagoon sludge is a nutrient-rich resource that requires frequent removal and sustainable use to minimize any adverse environmental impacts. This works scope will investigate two key work scopes: (1) impact of lagoon sludge level on irrigation frequency and nutrient composition of lagoon supernatant, and (2) compare technical and economic performance of industrial drying systems that can be adopted in NC to dry lagoon sludge.

The CNR torrefaction machinery at Lake Wheeler Field Laboratory will process up to 6000 lbs. of Miscanthus pellets/Arundo donax grass and unspecified biomass pellets supplied by Jacobs Engineering. These results will be provided to Jacobs as part of an EPA project administered by Jacobs Engineering.

Abstract: The production of liquid fuels from biomass requires a steady flow of suitable inputs to fully utilize plant capacity and maximize returns on investment. For North Carolina, full use of a plant may requires storage of herbaceous and wood feedstocks because of the seasonality of production (grasses) and the difficulty of harvesting forests in wet conditions. Biofuels producers need a buffer of feedstock in the late winter to spring period when switchgrass has been harvested and new crop production has not begun. NCSU has found that soft hardwood will be the primary source of alternative feedstock as it has a higher conversion rate than loblolly pine. The ability to selectively purchase maple, sweetgum and blackgum chips year-round will help reduce their costs and ensure that only compatible species are included in the hydrolysis process. Storage of these woody feedstocks will allow for greater certainty in production. NCSU will partner with Chemtex in this project as they will be producing cellulosic ethanol in Spring Hope next year and are currently determining the logistics of provisioning their plant with soft hardwood feedstock. Several methods for storage of hardwood will be investigated in this project: Ensilage Woodchips combined with leaves may undergo fermentation in a low oxygen environment. NCSU will perform medium scale experiments on hardwood chips with and without tree leaves and with and without added forage in both summer and winter. We anticipate low moisture loss. Chemtex will test the resulting products for suitability for their fermentation processes. Ensilage-Drying This is a combination of simple ensilage with provisions made for the removal of water vapor generated in ensilage process. This is described fully in expired US patent 4935035. The same treatments as above will be followed and Chemtex will do similar analysis. Low energy drying Woodchips will be dried with existing low energy drying systems developed at NCSU by Chris Hopkins. NCSU has 3 systems on hand: Batch dryer for drying in thick layers (up to 4’). This system is useful if handling woodchips is seen as low cost and electricity to drive fans is relatively inexpensive. Conveyor drying for thin layers. This systems involves drying using both solar energy and latent heat in unsaturated air with traditional rubber belt conveyors. Perforated conveyor drying for medium layers using both solar and latent heat energy in the air. This system may be the most efficient but requires use of belting material not previously used in drying wood chips. We do not anticipate large differences in the final product of chips dried with these systems, but will test them for their relative energy and labor input performance with soft hardwood chips. In-Field Drying is a system currently being funded by NCDA and we can add additional trials to specifically to look at the drying rates of soft hardwoods and the efficiency of chipping and storing these chips. NCSU will design and implement this study with Chemtex as primary partner. NCSU will collect data on the time and temperature profiles, energy use (diesel, electricity) of each method of drying, as well as machine time. Chemtex will provide input on costs of implementing these processes in their NC plant and provide data on ethanol conversion rates for each in comparison to their standard fresh wood chip results. Mark Conlon will gather engineering data on implementation costs and combine it with the above information to estimate ROI of implementation of each system and estimate on reliability and overall system performance. The outcome of this study will be academic and trade journal articles on the best methods for smoothing the feedstock flows in North Carolina given the performance of preserved soft hardwoods.

In the three months of the original project NCSU had identified foresters with ongoing forest harvest sites appropriate for this study. We now have the proper contacts and groundwork in the region to promptly re-initiate the study. In this renewed study, NCSU will document the establishment, drying rates and processing of stacked logging residues on two sites in Western North Carolina. We will re-establish contacts for installation of the drying test sites, install the drying piles on active logging operations, measure machine operations for piling, take monthly measures of drying over 10 months, document chipping effectiveness on dried material and write up results. Contemporaneous with the conduct of the drying study, tours of the operations and ongoing drying will be made with loggers and landowners so that the feasibility of a forest based biofuels industry can be discussed with these forest stewards.

This work will begin in September, 2015 and continue through April, 2016. It will provide a small commercial scale demonstration of the supply chain for flue cured tobacco stalk fiber production. In consultation with RJRT for this proposal, NCSU will focus its efforts on the production of tobacco silage at a commercial scale using a contracted forage harvester. This material will be ensiled in one or more large piles using techniques developed over the last two years. Finally the ensiled material will be dried using NCSU developed and fabricated drying equipment. Pith and skin will be separated and sorted from the woody fraction with a forced air system.

At present the majority of tobacco produced in the United States is for consumption; however, due to a relatively large biomass, potential exists for tobacco to serve as a source for ethanol production. Research programs in the Crop Science, Entomology, and Forest Biomaterials Departments will serve to address production related issues pertaining to crop growth, insect management, and harvesting.

Introduction NCSU has worked with RJ Reynolds Tobacco Company Inc. (RJRT) over the past year to understand the benefits and constraints of a flue cured tobacco stalk supply chain supplying fiber. Improved fiber qualities from fresh and ensiled flue-cured stalks was demonstrated in 2013, additionally flue-cured stalks are a larger source of potential supply. This project will identify benefits and constraints of a variety of methods of preserving flue-cured tobacco stalks with silage techniques. It will document the required supply chain steps needed to deliver preserved tobacco stalk fiber for further processing. This preliminary work in fall 2014 and winter 2015 will facilitate larger scale work with the 2015 year’s crop. Further work in 2015 is proposed to include additional work on a larger scale drying project. Methods of Ensilage NCSU will organize the harvest, ensiling and analysis of ensiled products with a number of methods depending on budget and agreement with RJRT. These may include ensilage in piles, bins, dumpsters, lined super sacks, tobacco bins or others. Silage inoculants (Lactobacillus) and their effect on tobacco wood substitute qualities will also be tested in small batches (20-30 gallon volume). We may work with RJRT contracted growers and may use the modified corn silage harvester developed by RJRT to source material for this study. NCSU will also study the feasibility of sorting moist ensiled stalks to improve downstream processing efficiency. Deliverables The main benefit of this project will be gaining first-hand experience with the methods of ensilage investigated. In addition, NCSU will document several aspects of ensilage

North Carolina State University (NCSU) will investigate and report on the viability of improved woody biomass delivery systems for biofuels production in the underdeveloped forest products markets of Western North Carolina. NCSU, Southern Research Institute (SRI), North Carolina Association of Professional Loggers (NCAPL) and Peterson Corporation will coordinate their efforts in demonstrating the size and location of the biomass resource, the viability of production techniques for woody biomass resources and the suitability of the existing resource to biofuels production being developed in North Carolina. This will be done through the coordination of the NCSU which will use demonstrations and data generated to describe the market structures that will be motivate affordable, sustainable supply of woody biomass to biofuel conversion. NCSU?s FIBREAnalytics service center will estimate the woody biomass availability and accessibility to existing road and rail networks in a GIS framework and forecast biomass supplies and demands into the future for the western region of North Carolina. This information will be used to report the potential biofuel feedstock and suggest high return locations for plant siting.