Process Analysis for the Production of Hydrogen and Liquid Fuels from Oil Shale

Abstract

AbstractShale to liquid (STL) and syngas to liquid (GTL) fuel techniques are applied to vast discovered resources of oil shale to fulfil current and future liquid fuel demands. To utilize the different constituents of oil shale efficiently, cases 1 and 2 were designed to produce liquid fuels and hydrogen as end products. In case 1, which produces shale oil and retorting gas from oil shale that are further processed by shale oil hydrogenation and retorting gas steam reforming to produce liquid fuels and hydrogen, respectively. For comparison, case 2, including oil‐shale retorting, retorting gas steam reforming, shale oil hydrogenation, and Fischer–Tropsch synthesis technology, was also established. Cases 1 and 2 are compared (with respect to end products and energy efficiencies) with each other by modeling and simulating three scenarios for case 1 and four scenarios for case 2. The simulation results show that the third scenario of case 1 and the fourth scenario of case 2 provide the most important required end products, namely, hydrogen and hydrocarbon fuels. The overall production of hydrocarbon fuels in the fourth scenario of case 2 increases 0.95 wt % more than that of the third scenario of case 1, whereas the production of hydrogen reduces by 14.7 wt % and the external energy consumption is 20 % higher in the fourth scenario of case 2, relative to that of the third scenario of case 1. For the third scenario of case 1 and fourth scenario of case 2, the total energy efficiency of the system is 43.45 % (high heating value (HHV)) and 43.16 % (HHV), respectively. The whole system is modeled and simulated in the Aspen Plus V8.4 program and the results are compatible with those of industrial and experimental data. Sensitivity analyses are performed to show the effects of various key operating parameters on the production yield of shale oil, retorting gas, and hydrogen.