The effect of green hydrogen feed rate variations on e-methanol synthesis by dynamic simulation

Abstract

Methanol is a promising fuel and important intermediate chemical in the transformation of renewable power to chemical products since it can be directly synthesized from captured CO 2 and electrolytic H 2 . However, the intermittency of renewable power generation poses challenges to green methanol production process design and operation, necessitating high operational flexibility to facilitate coupling with intermittent renewable power. In this study, a green crude methanol (a mixture of methanol and water from methanol synthesis) production process was dynamically modeled. The results show that the minimum load of the model is 20 %, with maximum allowable ramping rates of 3.25 %/minute for ramp-down and 2.10 %/minute for ramp-up between full and minimum load. The introduction of a standby mode, in which a make-up H 2 stream is supplied when electrolytic H 2 is unavailable, allows continuous operation of the process at the minimum load. With the constructed control structure, the model demonstrates that the process can effectively handle continuous variations of electrolytic H 2 input. • The minimum load of the model is defined by compressors' 20 % minimum operating point. • Maximum ramp-down and ramp-up rates of the model are 3.25 %/minute and 2.10 %/minute. • Methanol synthesis can operate continuously at minimum load in standby mode. • Constructed control structure handles effectively continuous variations in H 2 input.

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