(760f) Measurements and Modeling of Pressure Drop and Heat Transfer in ZoneFlowTM Structured Catalytic Reactors for Steam Methane Reforming

The recent increase in the availability of natural gas from shale gas has led to growing interest in upgrading methane to higher value chemicals. Steam methane reforming is the most widely practiced process for converting methane to hydrogen/syngas and its derivatives. The process is however strongly limited by heat transfer between the furnace and the process gas. To limit the pressure drop, large pellets have to be used, introducing important intra-particle diffusion limitations. Structured catalytic reactors are promising for intensifying the process and deal with the limitations encountered in conventional reformers.

In this work, detailed pressure drop and heat transfer measurements were carried out using various ZoneFlow^TM structured catalytic reactors and reference conventional pellets. Cold flow pressure drop measurements were carried out at atmospheric pressure and room temperature, with air flow rates ranging between 65 and 300 Nm³/h. To measure the heat transfer coefficient between the tube wall and the gas, tests were carried out at atmospheric pressure in the same range of air flow rates and imposing a furnace temperature between 100 and 500°C. Axial profiles of both the gas and tube wall temperatures were measured.

Correlations for the pressure drop, i.e. friction factor, and for the heat transfer coefficient were derived. Estimation of the model parameters and their confidence intervals and discrimination between different possible models was based on regression and physicochemical and statistical testing. The potential of ZoneFlow reactors to significantly decrease pressure drop and improve heat transfer is demonstrated.

To study the influence of the reduced pressure drop and intensified heat transfer on the reactor performance under typical industrial SMR conditions, simulations were carried out with a 1D heterogeneous reactor model coupled with independently determined models for the intrinsic reaction kinetics and for intra-catalyst transport. The differences between the performance of a conventional packed bed and a ZoneFlow structured catalytic reactor are analyzed.