Parallel implementations of scientific applications involving the simulation of reactive flow on structured grids are challenging, since the underlying phenomena include transport processes with uniform, computational loads as well as reactive processes having pointwise varying workloads. As a result, traditional parallelization approaches that assume homogeneous loads are not suitable for these simulations. This paper presents "Dispatch", a dynamic structured partitioning strategy that has been applied to parallel uniform and adaptive formulations of simulations with computational heterogeneity. Dispatch maintains the computational weights associated with pointwise processes in a distributed manner, computes the local workloads and partitioning thresholds, and performs in-situ locality-preserving load balancing. The experimental evaluation of Dispatch using an illustrative 2-D reactive-diffusion kernel demonstrates improvement in load distribution and overall application performance.