Investigation of anti-condensation strategies in the methanol synthesis reactor using computational fluid dynamics

Abstract

Flow mal-distribution in the shell side of the gas-cooled conventional reactor (CR) in the mega methanol plant is responsible for producing gas condensate in the catalytic zone. This phenomenon leads to catalyst agglomeration and efficiency reduction in the reactor. In this study, two novel and viable strategies, possible to be implemented in working reactors, are introduced to prevent condensation. In the first strategy, co-current mode (CCM), the reactant flow changes from counter-current into the co-current. In this regard, the feed inlet is replaced from the bottom of the reactor into the top. In the second strategy, changed-bed mode (CBM), the catalyst particles at the last two meters of the reactor are replaced with non-reactive ceramic balls. The results for three-dimensional computational fluid dynamics (CFD) in CR have been validated against previous study and industrial data, indicating close agreement. The main advantage of CCM and CBM is that the sudden temperature drop fails to occur at the end of the reactor. Consequently, the higher temperature of the products prevents water and methanol condensation. In addition, the CCM leads to a milder temperature profile throughout the shell side, which increases catalyst durability.