Reactor - coating and propene oxidation
With increasing industrial development the emission of various organic contaminants, such as volatile organic compounds (VOCs), and related substances is drastically increasing. To address this issue, new technologies must be developed to remove them from the atmosphere. Several methods such as adsorption on activated carbon, catalytic oxidation, and advanced oxidation techniques including photocatalysis have been developed. In particular photocatalytic advanced oxidation using a combination of ultraviolet (UV) radiation and TiO2 as an efficient, harmless and inexpensive photocatalyst is considered to be a promising technique. Still the design of an appropriate gas phase photocatalytic reaction system is required to implement this technology.
An suitable reactor system should allow for a sufficient irradiation of the photocatalyst, a large contact area between the photocatalyst and the reactants, and a small pressure drop along the reactor. In industrially relevant processes honeycomb-like catalyst supports are used, but due to the restricted penetration depths of light into the honeycomb structure, these systems are usually considered unsuitable for light induced processes. Here we will introduce a honeycomb-like reactor and a new design to guide the light into the channels to overcome this issue. An outline of the reactor is presented below.
Schematic illustration of the reactor design, including glass rods to internally illuminate the reactor. The glass rods are positioned equally spaced in the interior. Functionalized semiconductor coatings can be attached to the glass rods, or alternatively on the walls of the monolith, or both.
Nevertheless, in such a reactor design, the thickness of the catalyst layer is of utmost importance, and the difference between frontside illumination (e.g. the photocatalyst layer is coated on the walls of the honeycomb structure) or backside illumination (coating of the light guides) needs to be evaluated. These questions will be addressed in this assignment using the propane oxidation reaction to CO2 as a an appropriate model reaction.