A catalytic membrane micro-reactor for the direct synthesis of propene oxide

In this work, a catalytic membrane reactor for the direct epoxidation of propene oxide is developed. The titania and silica membranes synthesis method from an alcoxide precursor, TiO2 nano-particle powder and SiO2 colloidal solution is described. Stainless steel is used as a support for the intermediate ceramic layers. In order to obtain thin and crack-free membranes different parameters were optimized, such as drying conditions, calcination temperature, precursor concentration and viscosity of solution. The as-developed membranes were tested in a Wicke-Kallenbach cell under different operating conditions (temperature and pressure)

Gas–liquid dynamics at low Reynolds numbers in pillared rectangular micro channels

Most heterogeneously catalyzed gas–liquid reactions in micro channels are chemically/kinetically limited because of the high gas–liquid and liquid–solid mass transfer rates that can be achieved. This motivates the design of systems with a larger surface area, which can be expected to offer higher reaction rates per unit volume of reactor. This increase in surface area can be realized by using structured micro channels. In this work, rectangular micro channels containing round pillars of 3 μm in diameter and 50 μm in height are studied. The flow regimes, gas hold-up, and pressure drop are determined for pillar pitches of 7, 12, 17, and 27 μm. Flow maps are presented and compared with flow maps of rectangular and round micro channels without pillars. The Armand correlation predicts the gas hold-up in the pillared micro channel within 3% error. Three models are derived which give the single-phase and the two-phase pressure drop as a function of the gas and liquid superficial velocities and the pillar pitches. For a pillar pitch of 27 μm, the Darcy-Brinkman equation predicts the single-phase pressure drop within 2% error. For pillar pitches of 7, 12, and 17 μm, the Blake-Kozeny equation predicts the single-phase pressure drop within 20%. The two-phase pressure drop model predicts the experimental data within 30% error for channels containing pillars with a pitch of 17 μm, whereas the Lockhart–Martinelli correlation is proven to be non-applicable for the system used in this work. The open structure and the higher production rate per unit of reactor volume make the pillared micro channel an efficient system for performing heterogeneously catalyzed gas–liquid reaction

Towards a new propene epoxidation process. Transient adsorption kinetics measurements.

Applied Science

The kinetics of the propene epoxidation and water formation over gold-titania catalysts

Abstract only

Kinetics of the water formation in the propene epoxidation over gold-titania catalysts

The kinetics of the hydrogen oxidation were determined for a number of different gold catalysts supported on titania, silica, and silicalite-1. A dual site Langmuir-Hinshelwood kinetic model was able to describe the reaction well. The kinetic parameters are independent of the support. Water was found to be strongly limiting the hydrogen oxidation rate

Basic Principles in Applied Catalysis

Basic Principles in Applied Catalysi

The role of support in propene hydrogenation over gold-titania catalysts

No abstract