Design Optimization of a Heat Recovery ORC for a Novel Biomass to Methanol Plant

orc2019 Tracking Number 125

This work presents the optimization of ORCs for recovering waste heat from a novel process for the co-production of methanol and electricity from biomass. The process uses a flexible sorption enhanced gasification reactor, developed in the framework of the H2020 EU project FLEDGED. The heat integration study is particularly interesting because the process features multiple hot and cold streams at different temperatures (i.e., the calciner flue gases, the syngas coolers, etc.) making it necessary to optimize not only the ORC configuration (i.e., single vs. multiple pressure levels, regenerative vs. simple cycle, combined heat and power arrangement, etc.) but also the heat exchanger network. For two candidate working fluids, hexane and R1233zde, the cycle and heat integration are optimized using the p-h ORC superstructure and a systematic synthesis methodology recently proposed by Martelli et al. (2017). The optimization aims at maximizing the economic performance of the system taking into account the trade-off between efficiency and costs.