Liquid holdup and dispersion are reported for a column of 2 mm internal diameter, filled with 0.1 mm spherical particles, for multiphase flows with hydrocarbon liquid flow rates of 10-100 lL/min and nitrogen gas flow rates of 50-1000 lL/min using different tracers with varying diffusion coefficients and vapor pressures. It was found that the liquid holdup (liquid volume/external void volume) was between 0.65 and 0.85, with variations between different experiments and limited impact of flow rate on the holdup. The dispersion characteristics were very similar to single-phase dispersion. The particle Peclet number for dispersion was close to 0.2. This value was of the same order of magnitude -just a factor of two to three lower -as the value that was obtained without gas flow. Tracer volatility did cause the tracer to elude earlier, but did not cause significant additional dispersion. The results suggest that the fluid mechanical interaction between the gas and the liquid was very limited.

The step response, including various startup procedures, in a three-phase microreactor of 2 mm internal diameter packed with nonporous particles of 100 μm is reported. We demonstrate that the bed behaves reproducibly through many cycles of operating conditions. Interestingly, we find that the different startup procedures have little effect on the steady state that is achieved. In other words, minimal hysteresis was observed, in sharp contrast to larger-scale reactors with larger particles where prewetting has a remarkable impact on the hydrodynamic behavior. The powder-packed beds have very high liquid saturation values, and prewetting is not needed. At least four liquid-residence times were needed to achieve stable pressure drop and dispersion values over the bed. This indicates that the hydrodynamic response into a stable operation may well be the limiting factor that determines the rate at which kinetic experiments can be performed in high-throughput equipment.

In this paper, the technical and economic advantages of combining conversion technologies into a multi-dimensional plant primarily using regional biomass residues are investigated. The main objective is to show how locally available biomass can be used more effi ciently as a source for renewable energy and bio-based products. Therefore, not only is the theoretical perspective considered, but also a reality check for the local situation is taken into account. Although industrial attitude toward biorefi neries is positive, the effi cient production of a portfolio of bio-based products has not yet been implemented. A biorefi nery concept for Moerdijk (the Netherlands) was developed, focusing on grass refi ning, production of pyrolysis oil, biodiesel production, and bio-LNG production. Grass refi ning is the most experimental technique of all proposed conversion techniques. In terms of development, pyrolysis oil and bio-LNG production are in the demonstration phase. Anaerobic digestion and biodiesel production are proven techniques. It is shown that this concept allows for synergies with regard to the utilization of residue fl ows from internal processes. Furthermore, it is demonstrated that by integrating different conversion technologies, an economically feasible concept can be developed in which technologies, currently residing in a demonstration phase, can also be brought to the market.

We describe the co-current flow pattern of gas and liquid through micro-fabricated beds of solid and pillars under variable (i) capillary number, (ii) contact angle or wettability and (iii) pillar arrangement, i.e. modifying the distance between pillars or their size and comparing regular with more chaotic systems.