Numerical simulations of various reactors for the production of xylose from hardwood hemicellulose by dilute sulfuric acid hydrolysis have been developed to analyze the effects on reactor performance of heat and mass transfer as well as reaction kinetics. An economic objective function representing the incremental cost of producing a 10% xylose solution for fermentation to ethanol was calculated from the results of the reactor simulations to identify the operating conditions that minimize production costs for each reactor type. Lower production costs were estimated for percolation and continuous counter-current reactors; the cost for xylose production in a continuous co-current reactor is significantly higher. Production of ethanol from hardwood hemicellulose is not economical with any of the reactors considered, but the models developed here may be used to analyze other process alternatives for use of hemicellulose via production of xylose.