CIRCULAIR investigates the conversion of manure and straw into sustainable fuels for aviation and shipping. The core process, hydrothermal liquefaction (HTL), yields a viscous biocrude, a water phase containing soluble organics, effluent gasses and a solid phase. This report describes the initial version of a process model for HTL conversion, upgrading of HTL biocrudes, wet oxidation of HTL process water and methanol synthesis from evolving CO2 streams. Preliminary mass and energy balances that are derived from the process modelling provide the basis for an upcoming pre-evaluation of economic and environmental performance parameters. The process model will be further developed and refined over the course of the CIRCULAIR project.