© bhr group limited 2004 the fluid engineering centre process intensification flexplant - recent...

© 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


The FlexPlant


The FlexReactor

Key aspects of technology

Re-configurable end linkagesInjection point in turbulent zone22 tubes of which 10 filled

8 part filled4 empty tubes

Kenics static mixers for low pressure dropShell and Tube constructionHastelloy process sectionsShell-side heat transfer enhancement


FlexReactor: Specifications

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 kWExothermicity 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.

Mixing Times against Length

0.001

0.01

0.1

1

10

100

1000

10000

100000

1000000

10000000

100000000

1000000000

0.000001 0.00001 0.0001 0.001 0.01 0.1 1 10

Length (m)

Diffusion

STR

Static Mixer

1 Second

1 Minute

1 Hour

1 Day

1 Month

mcmmm10µm

FlexReactor

Dead Zone

ProtocolVessel


Chemistry

Acid Base NeutralisationVery Fast. Exothermic (55kJ/mol). Aqueous. Single Phase

Biodiesel - Fatty Acid Methyl Ester2-phase to 3-phase to 2-phase mixing, mass transfer limitedHigh and Low Viscosity mixingmedium to long residence times (several minutes to hours)Low exotherm (~3kJ/mol)

Grignard HydrolysisHighly exothermic (~350kJ/mol), fast reactionPrecipitation of fine solids + organic/aqueous mixture


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)


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


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


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


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?


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 the fluid engineering centre process intensification flexplant - recent...

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