Henk M. van Veen

Stable Hybrid Silica Nanosieve Membranes for the Dehydration of Lower Alcohols

A thirst for water: Organic-inorganic hybrid silica nanosieve membranes with narrow pore size distributions were developed for the separation of binary (bio)alcohol/water mixtures, for example, to remove water from wet biofuels during production. These membranes dehydrate lower alcohols and show a stable performance in the presence of significant amounts of acetic acid.

Simulation of a hybrid pervaporation-distillation process

Abstract This study explores the possibility of simulating a hybrid pervaporation membrane process with the help of Aspen Plus™ (Aspen Tech) flowsheeting. Because Aspen Plus does not contain membrane modules in its Model Library, the pervaporation membrane is simulated within Excel Visual Basic for Applications (VBA). Excel VBA is then linked with Aspen Plus to perform the hybrid simulation. In this way, the user can control the simulation even during the calculations. Case studies, in which industrially relevant hybrid distillation–pervaporation processes are simulated, are used to test the program. First, the dehydration and recycling of ethanol in an industrial plant is looked at, to explore whether an economic improvement can be established with a hybrid process. Secondly, the same is done for the purification of acetic acid in an industrial plant. The results presented here indicate the value of this software as a design tool.

Plasma-deposited hybrid silica membranes with a controlled retention of organic bridges

Hybrid organically bridged silica membranes are suitable for energy-efficient molecular separations under harsh industrial conditions. Such membranes can be useful in organic solvent nanofiltration if they can be deposited on flexible, porous and large area supports. Here, we report the proof of concept for applying an expanding thermal plasma to the synthesis of perm-selective hybrid silica films from an organically bridged monomer, 1,2-bis(triethoxysilyl)ethane. This membrane is the first in its class to be produced by plasma enhanced chemical vapor deposition. By tuning the plasma and process parameters, the organic bridging groups could be retained in the separating layer. This way, a defect free film could be made with pervaporation performances of an n-butanol–water mixture comparable with those of conventional ceramic supported membranes made by sol–gel technology (i.e. a water flux of ∼1.8 kg m−2 h−1, a water concentration in the permeate higher than 98% and a separation factor of >1100). The obtained results show the suitability of expanding thermal plasma as a technology for the deposition of hybrid silica membranes for molecular separations.

On the enhancement of pervaporation properties of plasma-deposited hybrid silica membranes

The separation performance of a polymeric-supported hybrid silica membrane in the dehydration process of a butanol–water mixture at 95 °C has been enhanced by applying a bias to the substrate during the plasma deposition.

MEMBRANES FOR HYDROGEN PRODUCTION WITH CO2 CAPTURE

Publisher Summary This chapter provides an overview of the current status of the membrane development as a part of the R&D trajectory of hydrogen membrane reactors at Energy research Centre of the Netherlands (ECN). It focuses on the development of advanced technologies for power generation with carbon dioxide (CO2) capture. Membrane development at ECN focuses on the development of thinner and cheaper metallic membranes with higher permeation rates. Dense Pd/Ag membranes consist of a very thin layer of alloy supported by a porous inorganic substrate. The Pd/Ag membranes are made by electroless plating. Pure (gas-tight) palladium layers can also be prepared, varying in thickness between 0.5–4 microns. Silver is deposited on top of the thin pure Pd-membrane and sintered to obtain the required alloy composition. By optimizing the electroless plating technique, it is possible to manufacture membrane layers with a thickness of 3–5 microns on ceramic supports. The dense membranes show high hydrogen fluxes of up to 105 m3/m2hbar0.5 at 400°C. At low feed pressures, no nitrogen flux is detected and if the detection limit of the equipment is taken as the measured nitrogen flux, then the permselectivity is >1000.