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Process Intensification
FlexPlant - Recent Results
Andrew Green
Richard Jackson
PIN Meeting
7 December 2004
© BHR Group Limited
2004
The Fluid Engineering Centre
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
© BHR Group Limited
2004
Operating Pressure
Up to 20 bar
Operating Temperature
-70 to 250oC
Throughput
1 to 100 lt/hr
Pressure Drop
up to 15 bar
Heat Removal (typical)
up to 15 kW
Exothermicity of reaction
up to 750 KJ/mol
Residence time
2 secs - 30 mins
Size (l x w x h)
1000x300x400mm
Why?
Just ahead of the “dead zone” allowing predictable scale-up.
© 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
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
1
Pumping high and low viscosity liquids
Pumps set for high temp work
2
Start up/Shut down for Grignard and associated
pressure variations
3
Precipitation issues and 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
© BHR Group Limited
2004