© BHR Group Limited 2004 The Fluid Engineering Centre Process Intensification FlexPlant - Recent Results Andrew Green Richard Jackson PIN Meeting 7 December 2004 FlexPlant - Recent Results Andrew Green Richard Jackson PIN Meeting 7 December 2004

© BHR Group Limited 2004 Contents  Who are BHR?  Our approach - PI  The Flex Plant and friends  Commissioning tests  The Chemistry  Acid/Base  Biodiesel  Grignard  Conclusions and Questions

© BHR Group Limited 2004 The FlexPlant

© BHR Group Limited 2004 The FlexReactor Key aspects of technology Re-configurable end linkages Injection point in turbulent zone 22 tubes of which 10 filled 8 part filled 4 empty tubes Kenics static mixers for low pressure drop Shell and Tube construction Hastelloy process sections Shell-side heat transfer enhancement

© BHR Group Limited 2004 FlexReactor: Specifications Operating PressureUp to 20 bar Operating Temperature-70 to 250 o C Throughput1 to 100 lt/hr Pressure Dropup to 15 bar Heat Removal (typical)up to 15 kW Exothermicity of reactionup to 750 KJ/mol Residence time2 secs - 30 mins Size (l x w x h)1000x300x400mm

© BHR Group Limited 2004 Technology Well understood static mixing system. Studied for over 15 years. Mixing times Pressure drop High and Low Viscosity studies LIF, Reactive mixing, LDA Power dissipation CFD (including turbulence modeling) Software modeling Residence time distribution

© BHR Group Limited 2004 Why? Just ahead of the “dead zone” allowing predictable scale-up.

© BHR Group Limited 2004 Commissioning Physical tests to characterise system Heat exchange - U = 766 measured U = 700 predicted Mixing energy - Up to 150 W/kg Pressure Drop = 0.5 bar with water at 25°C Flow control set to 5 sec and 8 sec response To avoid oscillation and sympathetic corrections Integrity test to 38 barg

© BHR Group Limited 2004 Chemistry Acid Base Neutralisation Very Fast. Exothermic (55kJ/mol). Aqueous. Single Phase Biodiesel - Fatty Acid Methyl Ester 2-phase to 3-phase to 2-phase mixing, mass transfer limited High and Low Viscosity mixing medium to long residence times (several minutes to hours) Low exotherm (~3kJ/mol) Grignard Hydrolysis Highly exothermic (~350kJ/mol), fast reaction Precipitation of fine solids + organic/aqueous mixture

© BHR Group Limited 2004 Biodiesel Reaction Reaction of Methanol and Vegetable Oil with a Sodium Methoxide Catalyst. High Viscosity and Low Viscosity Pumping Water sensitive reaction Cleaning and startup issues Little sensitivity to stoichiometry 2-phase, 3-phase, 2-phase system Mass transfer limited

© BHR Group Limited 2004 Biodiesel Reaction Data Obtained: 3 kJ/mol exotherm 50°C Reaction Temperature 3.6 mins Residence time 3 bar pressure drop across all 22 tubes 97% complete reaction under these conditions Separation in 5 mins (cf. Intense protocol batch took 3hrs)

© BHR Group Limited 2004 Grignard Hydrolysis Phenyl magnesium chloride reacted with water Highly exothermic Water/Organic/inorganic solid 3-phase system Fine precipitate forms high viscosity gel Fast kinetics Reaction Zone Critical

© BHR Group Limited 2004 Grignard Hydrolysis Results: Start-up Critical!!! Shut-down Critical!!! Change of conditions - Unstable flow periods 350 kJ/mol reaction enthalpy 1.3 kW power output Overall success

© BHR Group Limited 2004 Problems/Solutions Three main issues with the running of these trials 1Pumping high and low viscosity liquids Pumps set for high temp work 2Start up/Shut down for Grignard and associated pressure variations 3Precipitation issues and safety of non-return valves

© BHR Group Limited Pumping Problems Biodiesel reaction Oil pumping is easy with moderate pressure drop Methanol is much less viscous and took 60-80% of pump power despite low flow rates. Consequently changes to oil flow rate caused stalling of methanol flow and subsequent surge as the pump recovered.

© BHR Group Limited Pumping Problems F1 = Oil : F2 = Methanol

© BHR Group Limited Start/Stop Issues The Grignard process was most problematic.

© BHR Group Limited Start/Stop Issues In such a sensitive system small variations in flow can cause partial blockage from swings in the local stoichiometry. In this case the problem was all due to trapped water in the non-return valves. Careful purging prevented this.

© BHR Group Limited Safety of non-return valves The non-return valves were of the gravity disc type to reduce pressure drops. Trace amounts of water caused small amounts of precipitate. This prevented a good seal when flow reversed and allowed leakage.

© BHR Group Limited Safety of non-return valves

© BHR Group Limited 2004 Conclusions The FlexPlant works! Start-up and Shut-down are non-trivial but workable Precipitations can be processed Approximate thermodynamic data can be calculated Approximate Kinetic data can be calculated Gives scaleable pressure drop and flow data Is it safe?

© BHR Group Limited 2004 Conclusions (2) Process Intensification uses more extreme conditions Reaction rates are faster (not mixing limited) Little or no reagent build up Higher temperatures for a much shorter time (cf. Batch) Low inventories of reacting materials Devices capable of enormous pressures Generally more selective and higher purity than batch