An economic analysis was conducted for an algae hydrothermal liquefaction (HTL) and biocrude upgrading system with alternative aqueous phase treatment methods. Using experimental data, three different methods were modeled and compared: 1) direct recycle HTL aqueous phase to the algae farm, 2) catalytic hydrothermal gasification (CHG), and 3) anaerobic digestion (AD). Direct recycle consumes the most natural gas because unlike AD and CHG, no methane is generated from the aqueous phase organics. However, direct recycle has the lowest cost compared to other two cases because it only requires the addition of pumps and buffer tankage related to aqueous phase recycle. The CHG and AD cases require significant capital and operating costs, which increase the minimum fuel selling price (MFSP) over the direct recycle case by 11% and 2.9%, respectively. CHG and AD respectively increase the conversion cost (excludes the cost to grow, harvest, and dewater algae) by 75% and 21%. Sensitivity analysis suggests that the key factors affecting the total cost of fuel production are the feedstock cost, biocrude yields, the plant scale, and the method of aqueous phase treatment.
Revised: May 30, 2019 |
Published: May 1, 2019
Citation
Zhu Y., S.B. Jones, A.J. Schmidt, K.O. Albrecht, S.J. Edmundson, and D.B. Anderson. 2019.Techno-Economic Analysis of Alternative Aqueous Phase Treatment Methods for Microalgae Hydrothermal Liquefaction and Biocrude Upgrading System.Algal Research 39.PNNL-SA-137970.doi:10.1016/j.algal.2019.101467