Evaporation in porous media is a process of particular interest in many applications, ranging from water management of proton exchange membrane fuel cells to thermal management of lab-on-a-chip applications, etc. The evaporation process in porous media typically experiences three main periods, among which the first period, named the constant rate period (CRP), performs the most efficiently in removing liquid. Therefore, it is a common aim to prolong the CRP for as long as possible and increase the evaporation rate in the CRP as high as possible. In this presentation, we first propose a multicomponent multiphase lattice Boltzmann model for pore-scale study on the convective equation in porous media. We then apply the model to simulate the convective evaporation of a dual-porosity medium and investigate the effects of inflow Reynolds number (Re), vapour concentration (Y_in) and contact angle (θ) on the evaporation process. A universal scaling formulation for the evaporation rate during CRP is found. Furthermore, we propose an optimized design of porous media by combining two heterogeneity effects:  increasing contact angle and pore size towards the inside. Compared with the reference case (maximum evaporation rate achieved before), the optimized design can extend the CRP from the degree of saturation S>0.64 down to S=0.12, and decrease five-fold the time needed to reach S= 0.05.