Dynamic Versus Steady-State Operation Modelling of Power-Biomass to Liquid Fuels Processes : A Techno-Economic Assessment

Abstract

For effective climate change mitigation, the share of renewable energy should be increased. Also, for low-emission carbon neutral aviation, synthetic fuels from renewable energy sources are assumed to be increasingly used in the future. The fluctuating nature of the renewable energies results in periods with production exceeding the demand. Consequently, some kind of energy storage is needed to balance power supply and demand. The X-to-Liquid routes proved to offer promising solutions in the chemical energy storage area, and this work considers the Power-Biomass-to-Liquid (PBtL) process as an energy storage solution. Yet, publications [1, 2] concerning the PBtL process discuss only the steady-state mode operation mode. However, since renewable energy is of a fluctuating nature, the dynamic process operation is of a particular interest.This thesis compares the steady-state and dynamic operation mode for a PBtL process. The plant size is scaled to an 24.5 MW electrolyzer power input The plant size is scaled to an 24.5 MW electrolyzer power input. These process operation modes simulated on Aspen Plus and Aspen Dynamics. Moreover, they are economically assessed with the DLR in-house program TEPET. The dynamic mode results in a NPC of 5.06 el , while the steady-state results in 3.84 €/l. The FCI of the dynamic mode amounted to 2.45 times that of the steady-state. The FT products per annum in the dynamic mode is 92% of that of the steady-state mode.