Hydrothermal liquefaction (HTL) of algae in a continuous flow reactor to produce bio-crude oil requires careful control of flow rates and heating rates to allow sufficient reaction time while preventing the formation of clogs. In the pilot scale HTL reactor system, the original design parameters allow for flow rates up to 250 mL/min. The reaction conditions needed for processing of a wastewater-grown algae species, Galdieria sulphuraria are 350°C at 2600 psi at 5-10 wt.% solids loadings in water. In a batch reactor, the needed holding time was 30-60 min. Since the continuous flow reactor can achieve much higher heating rates, the needed reaction residence time will need to be determined. The reactor has been successfully run for 4 hours at 300°C, 1500 psi and a 1.5 wt.% solids loading. Recent modifications allow the reactor to operate at the higher temperature and pressure. To balance the trade-off between flow rate and residence time, new flow and heat transfer parameters need to be calculated and measured to account for the changes in slurry properties at the new sub-critical water conditions.
- Calculate flow and heat transfer parameters for reactor at new conditions with known information about slurry characteristics; compare calculated parameters to those of other continuous flow HTL reactors in literature.
- Assist in residence time determination studies using phenol as a tracer.
- Compare HTL reaction yields with those expected based on calculated flow and heat transfer parameters, and results from batch reaction experiments.