Solid-oxide fuel cells for unconventional oil and gas production

Abstract

This dissertation presents a novel, cost-effective, environmentally sustainable method for converting United States' vast oil shale reserves into crude oil. Geothermic Fuel Cells (GFC) are designed for in-situ oil-shale processing. When implemented, the GFC is placed underground within an oil-shale formation; the heat released by the high-temperature solid oxide fuel cells within the GFC during electricity generation is used to upgrade oil shale into “sweet” crude oil. The world's first Geothermic Fuel Cell prototypes were designed and built by Delphi Powertrain Systems; their performance was characterized at the Colorado Fuel Cell Center (Golden, CO, USA). Following indoor, laboratory operation and validation of two GFC modules, three multi-stack modules were assembled into a nine-stack GFC that was integrated with a natural gas fuel processor and ancillary components, and operated underground within the geology at the Colorado School of Mines campus. Extensive experimental data collected during GFC testing was used to calibrate a steady-state system model in Aspen Plus to predict the GFC stacks' electrochemical performance and the heat-rejection from the module. Following model validation, further simulations are performed for different values of current, fuel and air utilization to study their influence on system electrical and heating performance. The model is used to explore a wider range of operating conditions than can be experimentally tested, and provides insight into competing physical processes during Geothermic Fuel Cell operation. Results show that the operating conditions can be tuned to generate desired heat-flux conditions as needed across applications. A maximum combined-heat-and-power-efficiency of 90% is simulated in the parametric study. Using simulation data from the GFC model, a continuous, non-convex nonlinear multi-objective optimization model is developed in AMPL to optimize the design and dispatch of a single GFC heater well. The optimization model seeks to maximize the system heating and electrical efficiencies while minimizing costs. The optimal design and dispatch strategy obtained using the KNITRO 12.2.0 solver yielded a well-head cost of 37 $/bbl for the oil and gas produced using the GFC technology and a maximum combined-heat-and-power-efficiency of 79%.