The curing of flue-cured tobacco (Nicotiana tabacum L.) is an energy intensive process and represents a significant portion of the overall cost of production. Given the goal of the industry to reduce the environmental footprint of tobacco production and the energy demand of curing, attention has been directed to explore options for the use of renewable fuels for heating tobacco barns. A two-year study conducted at the Virginia Tech Southern Piedmont Center evaluated the effectiveness and cost of curing flue-cured tobacco with a wood pellet burner. Additionally, field studies were conducted to evaluate the feasibility of on-farm production of biomass fuel crops as well as on-farm manufacture of biomass fuel pellets. The first time use of a wood pellet burner with an air-to-air heat exchanger in a bulk curing barn proved to be a viable alternative to a conventional propane fueled burner. Curing cost averaged $0.05 with the pellet burner compared to $0.04 per kilogram of tobacco with the propane burner. The increase in cost was offset by a 90 percent reduction of CO2 emissions with the use of wood pellets. The use of low lignin grass varieties did have an impact on biomass pellet properties. Pellet testing revealed high ash and chloride levels which could be problematic using a high efficiency wood pellet burner. Full maturity harvest of annual grasses fertilized with 112 kg per ha N resulted in higher yields. However, fertilizing for maximum yield would increase the CO2 footprint for biomass fuel pellet production. / Master of Science / Curing flue-cured tobacco (Nicotiana tabacum L.) is an energy intensive process consuming large quantities of both propane and electricity and represents the second highest overall production cost. The tobacco as a whole has a goal to reduce the environmental footprint of tobacco production and the energy demand of curing. In order to produce the crop more sustainably, attention has been directed to explore options for the use of renewable fuels for heating tobacco barns. Currently utilizing renewable fuels is limited to a small number of wood-fired hot water boiler systems. A two-year study conducted at the Virginia Tech Southern Piedmont Center evaluated the effectiveness and cost of curing flue-cured tobacco with a wood pellet burner. Additionally, field studies were conducted to evaluate the feasibility of on-farm production of biomass fuel crops as well as on-farm manufacture of biomass fuel pellets. The first time use of a wood pellet burner with an air-to-air heat exchanger in a bulk curing barn proved to be a viable alternative to a conventional propane fueled burner. The wood pellet burner with air-to-air heat exchanger was compared to a high efficiency prototype propane burner. Curing cost averaged $0.05 with the pellet burner compared to $0.04 per kilogram of tobacco with the propane burner. The increase in cost was offset by a 90 percent reduction of CO₂ emissions with the use of wood pellets. Curing cost with the wood pellet burner is expected to be lower than that of a more traditional propane burner and curing barn. The use of low lignin grass varieties did have an impact on biomass pellet properties, however more replications testing on-farm produced pellets is necessary in order strengthen the validity of these results. Pellet testing revealed high ash and chloride levels in on-farm produced biomass pellets which could be problematic using a high efficiency wood pellet burner, but may be less precarious if paired with a more rudimentary burner. Full maturity harvest of summer annual grasses fertilized with 112 kg per ha N resulted in higher yields. However, fertilizing for maximum yield would increase the CO₂ footprint for biomass fuel pellet production. Based on these results, purchasing commercially made, readily available wood pellets is the best alternative to using a renewable fuel to cure flue-cured tobacco. This practice would allow growers to incrementally adopt the use of a renewable fuel while providing comparable operation ease as traditional propane burners.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/82554 |
| Date | 23 March 2018 |
| Creators | Brown, Robert T. |
| Contributors | Crop and Soil Environmental Sciences, Reed, T. David, Teutsch, Christopher D., Ignosh, John |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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