The underlying basis for the exceptional performance of a heat exchanger preheater for a novel short contact time batch reactor (SCTBR) was investigated. Three levels of analysis, ranging from equilibrium calculations to a finite difference solution of the transient heat transfer problem, were used to solve the equations governing heat and momentum transfer. For a target reaction temperature of 400 degrees C, the tetralin exit temperature from the heat exchanger preheater was calculated to be 392 degrees C initially, down to 376 degrees C. This is in reasonable agreement with a measured 392-395 degrees C upon injection into the reactor. The small discrepancy is due, in part, to an unaccounted heat contribution from the reactor. This agreement confirms the utility of the preheater configuration and therefore the SCTBR as a tool to minimize heat-up effects in reaction analysis.