Techno-Economic Analysis of Fast Pyrolysis and Upgrading Facilities Employing Two Depolymerization Pathways

We evaluate the economic feasibilities of fast pyrolysis and upgrading facilities employing two depolymerization pathways which are fluid catalytic cracking (FCC) with a zeolite catalyst and hydrocracking. Three scenarios are analyzed: two-stage hydrotreating followed by FCC of the aqueous phase of pyrolysis oil with hydrogen purchasing; two-stage hydrotreating followed by FCC of the aqueous phase of pyrolysis oil with hydrogen from steam methane reforming; one-stage hydrotreating followed by hydrocracking. The main products for the first two scenarios are the petrochemicals while transportation fuels and hydrogen are the main products for the third scenario. The two pathways are modeled using Aspen Plus® for a 2000 metric tons/day facility. Equipment sizing and cost calculations are based on Aspen Economic Evaluation® software.

The bio-oil yield is assumed to be 65% based on dry biomass and we calculate the internal rate of return (IRR) for each scenario as functions of the costs of feedstock, fixed capital investment (FCI), hydrogen and catalyst costs and projected revenues for the facility. The analysis indicates that a facility employing two-stage hydrotreating followed by FCC of the aqueous phase of pyrolysis oil with hydrogen from steam methane reforming is able to generate the highest IRR among the three scenarios. Facility IRRs are 7.6%, 13.3% and 9.8% for facilities employing the three scenarios, respectively. Sensitivity analysis demonstrates that product yield, FCI, and biomass cost have the greatest impacts on facility IRR. Monte-Carlo uncertainty analysis shows that two-stage hydrotreating followed by FCC of the aqueous phase of pyrolysis oil with hydrogen from steam methane reforming is of low risk for investment.