In this work, monolith reactor design is optimized as discussed in details in all previous accomplished work (Al-Duweesh et al., 2021; Duweesh et al., 2019). Additional computation is used to examine the non-isothermal behavior of this 3-D monolith reactor featuring a structured desired geometry that satisfies many reaction advantages in design. To optimize the fully developed laminar flow, nonisothermal, adiabatic monolith reactor featuring both surface and bulk first order reactions. COMSOL Multiphysics 5.4® was used to simultaneously solve for the species mass continuity, and energy equations. The resulting mass fraction, velocity and temperature profiles are then employed to compute the outlet reactant dimensionless mass fraction and temperature. It is numerically established that the velocity is optimum at its upper bound while transition to turbulence flow is eliminated. This enables the search for the optimum to be carried out in the two-dimensional space of the channel’s dimensionless inverse hydraulic diameter and width. Numerous numerical calculations for various cross-sections show that the global optimum is reached at the maximum allowable channel width , and the minimum allowable channel hydraulic diameter <10. For reactions with a significant level of extremity, the dimensionless average outlet temperatures exhibit a weak dependence on and a strong dependence on, attaining higher values as decreases for any fixed value of . This concludes hot spot occurrence at the corners of the monolith reactor allows limitations on the hydraulic diameter to be more pronounced than the reactor width.
