Browsing by Author "McPhail, Ana"

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    Municipal Solid Waste as a Viable Alternative Fuel in the U.S.A.
    (2014-11-25) McPhail, Ana; Griffin, Robert; Alvarez, Pedro J.J.; El-Halwagi, Mahmoud; Medlock, Kenneth; Lin, Cynthia
    This thesis work evaluates whether municipal solid waste (MSW) may be a viable alternative and renewable fuel source within the United States. The framework for achieving this objective is split into two large, distinct studies. The first study discerns the relationship between MSW composition (including varying moisture), air pollutant concentrations and associated heating values. Models included AspenPlus® software for the deterministic simulation modeling of thermodynamic and pollution information, and U.S. EPA models WAR and WARM to determine the potential environmental impacts (PEI) and greenhouse gas emission equivalencies, respectively, for each MSW scenario. An economic profitability analysis was also conducted. This study focused on five high impact air combustion products: SO2, CO, CO2, NO and NO2. Results show that flue gas concentrations (and therefore PEI) depend on the composition and moisture of the MSW, in addition to the MSW to coal ratio. The recycled paper and composted organics scenario gave the lowest heating value (8,251 MBtu/lb). Approximate ranges for the WAR results (PEI/hr) are 7,410 to 7,663 for NO, 4 to 8 for NO2, 18 to 105 for CO, 30 to 46 for CO2, and 89 to 2,152 for SO2. WARM results show lower net CO2 emission equivalents to landfill MSW with reduced paper and organics, while combustion is preferred for MSW with paper, organics, or plastics reduction. Reduction in pollutant concentrations yielded a reduction in profit between ~20-30%. There were savings associated with emission costs by using MSW in lieu of coal: up to ~3.3% for NO, ~20-47% for NO2, and ~95% for SO2. In summary, the measurable impact MSW composition and moisture had on pollutant concentration, heating value, and economic parameters were important. The second study is used to link the information gathered in the first study with legislative actions locally and abroad. In this study, four unique scenarios and one aggregate scenario varied subsidies, health impacts, fines, energy credits and fiscal policy data and distributions using Monte Carlo analysis to evaluate and foster policy initiatives while determining the economic feasibility of MSW as a renewable fuel for municipalities. Results show the supply stack for electricity generation uses the cheapest fuel (coal), then the second cheapest (natural gas) until demand is met or more fuels are needed. The social marginal cost (SMC) without considering further policy changes yields costs of $0.165/kWh for coal, $0.209/kWh for NG and $0.349/kWh for MSW. Implementing policy changes for internalizing the health impacts currently paid for by the community and the aggregate impact of all scenarios would level the economic playing field for MSW, providing lower SMC’s of $0.327/kWh for MSW in both cases, and higher SMC’s for coal and NG in other scenarios such that the order of the supply stack changes. This work advances the fundamental understanding of the economic limitations and advantages, and the policies needed to foster further proliferation of MSW as a fuel.