Overcoming mass-transfer limitations in the Dual Bed Colloidal Suspension Reactor

Mass-transfer limitations are examined for a conceptual photoelectrochemical (PEC) cell “Z-scheme” reactor, the Dual Bed Colloidal Suspension Reactor (DBCSR). Modeling of the DBCSR shows mass-transfer limitations along the width of the reactor prevent full use of the channel photocatalysts. To overcome this challenge, recycling of product gas to sparge the electrolyte solution is proposed as a method to enhance mass transfer. Dimensionless mass-transfer correlations, based on experimental data obtained using two fabricated diffusion cells, are proposed to describe the mass-transfer rate. Additionally, the results suggest that reactor size influences solution convection patterns. An energy analysis is presented that shows that gas sparging is a low energy-consumption option to mitigate mass-transfer limitations.