Influence of channel geometry on hydrodynamics and mass transfer in the monolith film flow reactor

This paper describes a novel bioscrubber concept for biological flue gas desulfurization, based on the recycling of a cell suspension of sulfite/sulfate reducing bacteria between a scrubber and a sulfite/sulfate reducing hydrogen fed bioreactor Hydrogen metabolism in sulfite/sulfate reducing cell suspensions was investigated using batch activity tests and by operating a completely stirred tank reactor (CSTR) The maximum specific hydrogenotrophic sulfite/sulfate reduction rate increased with 10% and 300%, respectively, by crushing granular inoculum sludge and by cultivation of this sludge as cell suspension in a CSTR Operation of a sulfite fed CSTR (hydraulic retention time 4 days; pH 70; sulfite loading rate 05-15 g SO3(2-) l(-1) d(-1)) with hydrogen as electron donor showed that high (up to 16 g l(-1)) H2S concentrations can be obtained within 10 days of operation H2S inhibition, however, limited the sulfite reducing capacity of the CSTR Methane production by the cell suspension disappeared within 20 days reactor operation The outcompetition of methanogens in excess of H2 can be attributed to CO2 limitation and/or to sulfite or sulfide toxicity The use of cell suspensions opens perspectives for monolith or packed bed reactor configurations, which have a much lower pressure drop compared to air lift reactors, to supply H2 to sulfite/sulfate reducing bioreactors

Use of sulfate reducing cell suspension bioreactors for the treatment of SO2 rich flue gases.

Chapter 27 – Catalysts and Enzyme Reactors

Ultra-fast imaging of two-phase flow in structured monolith reactors : techniques and data analysis

Several aspects of the application of monolithic catalysts in multiphase reactions are highlighted: why, hydrodynamics and preparation. A bright future for monolithic systems in this area is predicted for application in chemical industry.

Potential of Monolithic Reactors in Catalysis; Multiphase Applications

Flooding limits and pressure drop of gas−liquid countercurrent flow have been determined in internally finned tubes, representing a single channel of an internally finned monolith It was found that with the appropriate liquid outlet geometry it is possible to achieve countercurrent annular flow at velocities that are relevant for hydrotreating of petroleum fractions Comparison with an unfinned tube showed that the longitudinal fins inside the tube stabilize the liquid layer against slug formation, especially at high liquid velocities The pressure drop was calculated using a countercurrent film flow model By taking the extra pressure drop caused by the end-effects into account, it was possible to predict the pressure drop of both the finned and the unfinned tubes in the wavy annular flow regime

Rolf K. Edvinsson

Papers

Effect of Entrance and Exit Geometry on Pressure Drop and Flooding Limits in a Single Channel of an Internally Finned Monolith