Phycocyanin to biocrude via the integration of isothermal/fast hydrothermal liquefaction and aqueous phase recirculation: Reaction products and process analyses

•First application of fast HTL with the recirculation of aqueous phase products.•A 600 kg·d-1 HTL system with aqueous phase recirculation were evaluated.•Fast HTL, mixing ratio of 2:4 and 1st recyle obtained the highest biocrude yield.•N-heterocycle and amide increased the biocrude yield but decreased its quality.•47% of wastewater discharges could be avoided by recirculation for three times.