Techno-economics of microalgae production and conversion to refinery-ready oil with co-product credits

摘要

The economics of the production of hydrotreated algal oil (HTAO) along with co-production of animal feed and nutraceuticals (omega-3 oils) was explored. Base case calculations were for commercial scale production of 10 000 barrels per day of HTAO with nutraceuticals claiming only 0.05% of the raw algae oil (AO). The sensitivity of economics to critical parameters was studied. The greatest sensitivity of sales price was to the algae doubling time. Doubling time might be reduced by increasing pond velocity or other mixing-inducing means. Other important parameters were oil content, CAPEX, and moisture content of post-extracted algal residue. Algal area weight productivity (g/m(2)/day) was calculated from four parameters: initial algal concentration, pond depth, residence time in pond, and algae doubling time. Using presently accepted operating parameter values and with co-product credits, the estimated plant gate price was similar to$10/gal. However, it was shown that there is significant potential for enhanced economics through moderate improvements in many areas. Credits for co-production of animal feed and nutraceuticals were $3.24/gal and $0.14/gal, respectively. At constant oil area productivity (gal/acre/yr), the trade-off between oil content and area weight productivity favors oil content. In the limit of 100% oil content (no solid co-product) a sale price of $7.90/gal was estimated. Hydrotreatment of AO was discussed. Municipal waste-water tertiary treatment was briefly discussed but not deemed viable on a large scale. An easy-to-use Excel spreadsheet for material and energy balances and economics was developed as a flexible scouting tool. The symbol '$' denotes US dollars. (C) 2015 Society of Chemical Industry and John Wiley & Sons, Ltd