Sorption-enhanced methanol synthesis in a dual-bed reactor: Dynamic modeling and simulation

• Dynamic modeling of a dual-bed sorption-enhanced methanol synthesis reactor.
• Introduction of flowing solids as water adsorbent to the first reactor.
• Using reaction heat in the second reactor to preheat feed gas to the first reactor.
• Favorable temperature profile along the dual-bed multifunctional methanol reactor.
• Significant enhancement in catalyst activity and methanol production rate.

This work considers a dynamic mathematical model of a dual-bed multifunctional methanol reactor (DMMR) in the face of long term catalyst deactivation. A configuration of two catalyst beds instead of one single bed with selective adsorption of water inside the first bed is developed for methanol production. Synthesis gas and flowing adsorbents are both fed to the first reactor of DMMR. Contact of gas and fine solid particles inside packed bed results in the selective adsorption of water from the methanol synthesis system which increases temperature and methanol production. This reactor functions at a higher than normal operating temperature and at very high yield. In the second converter, the heat of reaction is used to pre-heat the synthesis gas to the first bed. Thus, a more favorable temperature profile is observed in DMMR compared to single-bed multifunctional methanol reactor (SMMR), and conventional methanol reactor (CMR). This way, the catalysts are exposed to less extreme temperatures and hence, declining the catalyst deactivation via sintering. Moreover, a differential evolution (DE) algorithm as a robust method is applied to optimize the reactors length ratio. The results of this study show a higher methanol production and longer catalyst lifetime for DMMR.