Process Intensification

Process Intensification

Prof. Attilio Citterio

Dipartimento CMIC “Giulio Natta”

http://iscamap.chem.polimi.it/citterio/dottorato/

PhD

IN INDUSTRIAL CHEMISTRY AND CHEMICAL ENGINEERING (CII)

Chemical Engineering Mature Technology ????

room for innovation

Agricola De Re Metallica 1556

AD 2002 Needed

– Cleaner, intensified plants

» Less waste

» Higher activity, selectivity, efficiency

» Milder conditions

Process Intensification

Better Chemistry!

Better Chemical Engineering!

Process Intensification

‘Any innovative Chemical Engineering development leading to substantial improvements

in (bio)chemical manufacturing’

Stankiewicz& Moulijn , CEP 96 (2000)22, IECR 41(2002)1920

Re-engineering the Chemical Processing Plant, Marcel Dekker 2004

Reduction of Impacts of Products over their Entire Product Life Cycle

Distribution Design Design for efficient distribution

Raw Materials Design Design for resource conservation

Design for low impact materials

End of Life Design Design for re-use Design for re-manufacture

Design for disassembly Design for recycling Design for safe disposal

Usage Design

Design for energy efficiency Design for water conservation Design for minimal consumption

Design for low-impact use Design for service and repair

Design for durability Manufacturing Design Design for Cleaner Production

Product

Clean Production (CP) aims to reduce impacts of products over their entire product life cycle. Using much less to produce much more.

Batch Process Scale up

Lab scale

Kilo Lab

Pilot Plant

Manufacturing plant

Time Cost

Microchemical Systems – Scale Down and Out

~ 50 ml

~ 5 µliter 25°C

~ 5 liter flow?

temperature?

Pilot ^Production

~ 1 ml Not to scale

SCALE

DOWN

UP _UP

OUT

Fine and Pharma Industries – Micro-reactor Technology

Laboratory Pilot plant Scale-up Technology transfer Large scale production Discovery Development Production Distribution

Batch

Technology

from: Fine Chemicals Peter Pollak,

15-60 months 8-15 months

Laboratory Pilot plant Scale-up Technology transfer Large scale production

Production banks

One tool engineered to fit all needs

Advanced Flow

Reactor Technology

Paradigm Change in Chemical Plants

• The classical world-scale plant is phase-out model

• Paradigm change in plant engineering

• ‘Too late with products’ – time-to- market

• Modular plant technique; standard

• Micro process engineering will have a role

– more on plant philosophy than on absolute size

Same view in 2015

The chemicals industry is going through a tremendous period of change that will help define opportunities and challenges in both the short and the long term.

Dr. STEFAN-ROBERT DEIBEL, Pdt Corporate Engineering, BASF in CHE Manager 2, 2006

Roberge, Lonza

Nature 442, 7101 351-352, 2006.

Cost ≈ size^0.6

«The question of whether

microreactors are going to be used in the future, I think this

is already answered

«yes».

Dominique Roberge

“Doing More with Less”

Process Intensification (IP) is a strategy to adapt the process to the chemical reaction

and not anymore the physico-chemical transformation to existing, known, depreciated

but often inadapted equipment

i.e.:

• Adapting the size of equipment to the reaction

• Replacing large, expensive, inefficient equipments by smaller, more efficient and less costly

• Choosing the technology best suiting each step

• Sometimes combining multiple operations in fewer apparatuses.

• LESS = raw materials, space, time, energy, investment, inventory, ...

• MUCH = factors, order of magnitude!!

Process Intensification Strategy

Kinetics Kinetics

Heat transfer

Process Process

Hydrodynamic

Mass transfer

R. Bakker

in “Reengineering the Chemical Processing Plant”, Marcel Dekker

Ed., 2003.

Reach the inherent kinetics of phenomena Maximize the transfer rate

Fick Law : flow = coefficient × interface × gradient

Process Intensification Strategy

Principle 1:

multifunctionality ( design methodology) unit operations have to be “compatibilized”

Principle 2:

energetics

create force fields at a mesoscopic level

Principle 3:

thermodynamics

increase potential of reactants, by activity or diffusivity

Principle 4:

miniaturization to increase force fields microreactors, micromixing, microseparators, … microsensors, microvalves, …

MESO-Technologies

Process Characteristics in Intensified Plants

Low residence times, minimal effluent separation, energetic efficiency, zero wastes, limited supply, improved intrinsic safety, process flexibility, or specification adaptability, fast answer to market, improved controls, just in time production on order.

Raw Materials Green Chemistry

• Zero solvents

• supported Catalysts

• Safe reagents

Intensified

Process Product

Volume Reduction

• Shift from batch to continuous processes

• Use technologies with high mixing rates and heat transfer rates instead of conventional stirred tanks

• Consider the opportunity to improve the process technology and in meantime the chemical bases

• Use 'Plug and play' process technology to afford flexibility in a multiproduct environment.

Elements of Process Intensification

P

I

EQUIPMENTS

METHODS

REACTORS

EQUIPMENTS FOR NON-REACTIVE

OPERATIONS

MULTIFUNCTIONAL REACTORS

HYBRID SEPARATION

ALTERNATIVE ENERGETIC SOURCES

OTHER METHODS

EXAMPLES:

- Spinning disk reactor - Static mixing reactor - Monolithic reactor - Micro reactor

- Static mixer

- Compact heat exchanger - Spinning packed bed - Centrifugal absorption

- Integrated heat reactors - Reactive separations - Reactive milling - Reactive extrusion - Fuel cells

- Membrane Absorption - Membrane distillation - Absorptive distillation - Centrifugal fields - Ultrasounds - Solar energy - Microwave - Electrical fields - Plasma technology - Supercritical fluids - Dynamic Operation

Reactor

Some Examples of intensified Equipment

Design Considerations in Process Intensification

Process is based on batch or continuous technology?

• Identify the rate limiting steps (mass, heat transfer, mixing, etc.) in all equipment in the production units

• Line Balance : temporal cycles of all equipment evaluated in a batch plant.

• Understand well the base chemistry of the process and know how monitor it

• Identify appropriate equipments/modules/intensification concepts

• Eliminate, if possible, the solvents; use supported catalysts where possible, reduce pressure/temperature gradients, and increase the transport rate

• Mathematical modeling: mathematical analysis of single equipment and of all plant to understand the transport process rate to evaluate performances.

• Reduce the number of stages through multifunctional modules

• Multifunctional Equipments: used to perform different operations in one unit.

• Process intensification Equipments: are designed to improve productivity, selectivity, energetic efficiency.

• Alternative energy sources.

Stages of Process Intensification

• Determination of matter and energy balance

in all production equipment units.

• Line balance:

the time cycles of all equipments are evaluated in a batch plant.

• Understand well the chemistry basis of the process and monitor it

• Operation and equipment analysis:

is carried out following lab experiments on 200 mL to 1 liter scale.

• Mathematical modeling:

mathematical analysis of single equipment and overall plant to known the process transport rates to evaluate performances.

• Multifunctional equipments:

are used to carry out different operations in a single unit.

• Process intensification equipments:

are designed to improve productivity, selectivity, energy efficiency.

• Alternative energy sources

Characteristic of an Intensified Process

• Provide each molecule the same working sequence

• Make equal mixing and transport rate to reaction rate

• Optimize mass and heat transfer rate

• Push the reaction to its rate and not to the plant rate.

• Improve selectivity and yield

• Improve the product quality and validation

• A fast cleaning allows a rapid change of production

• Fast answer to the values of assigned variables

• In some cases, lab scale is just sufficient (volume typically is the

range of 250-1000 mL).

Nitroglycerine – Process Intensification

Rapid mixing via pumping Reaction time 7 min.

Inventory 60 Kg

Glicerina acido nitrico acido solforico

Slow mixing Reaction time 2 hrs

Inventory 1 ton.

Batch Reactor

~20000 liters pre-charge of organic

substrate and solvents

Gradual addition of Nitric acid

Feeding o pre-charged catalyst (H₂SO₄)

Possible services:

• Mixing – contact of reagents

• Mass transfer – from aqueous phase (HNO₃) to organic phase

• Heat removal

Product Feed raw materials

Organic Substrate Nitric Acid Catalyst

CSTR Reactor ~ 400 liters

Glycerol nitric acid sulfuric acid

Glycerol

Nitroglycerin + 3 HNO₃ H₂SO₄

+ 3 H₂O C

H₂ C H

O O C H₂ O

NO₂ NO₂ NO₂ C

H₂ C H

OH OH C H₂ OH

DSM 2000plus Technology for Urea

0 14000

22000

2

1968 1 38000

50000 64000 76000

3 4

4

3

1

3

2 2 2

1 4 5 4

1970 1985 1994

1

4 6

2

1997

Simple lay-out *** reduced piping *** less structural steel

1. Reactor 2. Stripper 3. Condenser 4. Scrubber

5. Pool condenser 6. Pool reactor

Equipment Characterized

by E & m Transfer Performances

Mass Transfer

Heat Transfer

Microreactor

Spinning Disk Reactor

Plate

Exchanger Loop

Reactor Jacketed

Stirred Tank Educter

Pulsed Column

Static Mixer Rotating Packed Bed

Static Mixer Plate Exchanger

Areas for Process Intensification (UO Combination)

• Reaction-separation: membrane reactors, reactive distillation

• Reaction-heat exchange

• Separation-heat exchange: Deflemmators or heat integrated distillation

• Reaction-separation-heat exchange: reactors with isothermal membrane

Reaction Heatexchange

Separation

COOLING WATER OUT

COOLING WATER IN LIQUID FEED

GLASS FLANGE AND ADAPTOR

WATER COOLED HEAT EXCHANGER

SAMPLE POTS (FOR ANALYSIS) INTERNALLY COOLED

SPINNING DISK

GLASS COVER

THIN CATALYST COATINGT

Spinning Disk Catalytic Reactors (SDR)

Peculiarity of SDR Reactors

• The liquid flow implies an intense back-mixing, therefore a nearly pure flow is obtained.

The residence time is low, typically few seconds. The thickness of liquid film is 500 µm and supports high viscosity

• The reactor uses a small volume

of the liquid (about 10 mL for a batch equivalent of 5 m

) and is easy to

installed even in limited space.

• In a SDR reactor, a liquid is feed at the center of a rotating disk and, as the liquid moves toward the edge, intense interfering waves form under the influence of centrifugal force. This allows to obtain very high heat transfer coefficients between the disk and the liquid, along with an high mass transfer between the liquid and the upper gas.

Waves also generate an intense local mixing.

Flex Reactor

Flex Reactor represents a family of reactors

designed to cover a wider spectrum of transport capacity, Heat transfer rate, and mixing intensity.

1. multiple feeding of reagents (in series or in parallel)

2. Sensors in the reactor (e.g. T, FT-IR, etc.) to follow the reaction course and to collect critical kinetic data.

Incorporation of other functionalities between piping (e.g. separation, further heat transfer)

• Flexible and robust design with reconfigurable connectors to one end

• Otherwise to both ends.

• Laboratory, pilot or productive scale unit,

Flex Reactor

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

m cm

mm 10µm

Flex Reactor

Dead zone

time (sec)

Catalyst: strong acid or Cationic Exchange Resin Amberlyst 15

(catalytic esterification)

Catalytic or Reactive Distillation

TAME

Sulzer Mellapak^TM Sulzer Mellapak^TM

Sulzer Katapak^TM

Feed

Reactive Distillation: Synthesis of Methyl Acetate

Eastman Chemical Co (1990)

Column reactor

Catalyst

Distil.

H₂O Catalyst

Reactor MeOH

MeOAc HOAc

Conventional Process

MeOAc

MeOH

H₂O AcOH

• High purity MeOAc

• Capital costs reduced to 1/5

• Energy

consumption also reduced to 1/5

Extractive distillation

Reactive distillation

Reaction

Reactive distillation

Distillation

Non Trivial Simplification

 Lower number of vessels

 Less pumps

 Less flanges

 Less equipments

 Less valves

 Less piping

 ...

but



Reactive distillation column is quite more complex



In the same vessel multiple unit operations occur



More complex to design



More difficult to control and manage

Synthetic membranes represent a growing area for gas, liquid, metal and microorganisms separations. These potentialities combine with big

energy save, a low cost modular construction and high selectivity for separated materials. Membrane based processes are quite widespread,

Membrane

In general, membranes have reached a commercial success in few

applications (biotechnology). The total word market is however

expected in expansion to more than 2.7 billions € in next years.

In membrane processes the feed steam is divided in two streams, one the retentate or concentrate and the other the permeate.

permeate

retentate mixtureFeed

Membrane module

p_f

p_i p_o

p p m

v l

P J d

µ ε

32

2

∆

=

2

i o

f

P P

p + P

∆ = −

J_v = permeate flow ε_m = membrane porosity d_p = mean pore diameter

∆P = trans-membrane pressure µ = viscosity

l_p = mean pore length

purge

Membrane Separation Processes

Definition: The term membrane most commonly refers to a thin, film-like structure that separates two fluids. It acts as a selective barrier, allowing some particles or chemicals to pass through while leaving others behind.

 This selectivity is used for the separation process.

 The selectivity is due to:

•

Size

•

Shape

•

Electrostatic charge

•

Diffusivity

•

Physico-chemical interactions

•

Volatility of products

•

Polarity/solubility of products

Membrane Separation Processes : Applications

• Product concentration, i.e. removal of solvent from solute/s

• Clarification, i.e. removal of particles from fluids, a special case being sterilization which refers to remove of microorganisms from fluids

• Removal of solute from solvent, e.g. desalting, desalination, demineralization, dialysis

• Fractionation, i.e. separation of one solute from another

• Gas separation, i.e. separation of one gas from another

• Pervaporation, i.e. removal of volatiles from non volatiles (usually solvents)

Membrane Separations:

• Are pervasive in the biotechnology and pharmaceutical industries

• Are often used by biological systems

• Are one of the fastest developing areas in separations

• Are often highly selective, compact, inexpensive and easy to operate

• Overall throughput is generally low and often must be run in parallel

Membrane Processes

Advantages



No heat generation



No phase change



Low energy requirements



Easily automated



High levels of containment



Specific size separation

Limitations



Membrane blockage

• Fouling

• Gel polarisation



Membrane affected by the conditions of pH, ionic

strength, etc.



Cleaning and maintenance



Product adsorption



Not generally steam sterilisable



Pore size distribution.

Membrane Materials

Organic Polymers

Polysolfone (PS)

Polyethersulfones (PES) Tetrafluoroethylene (Teflon) Cellulose triacetate (CA) Regenerated cellulose Polyamides (PA)

Polyvinylidedefluoride (PVDF) Polyacrylontrile (PAN)

Polyisoprene (PI) Polycarbonates (PC) Polyimides (PIM)

Inorganics

γ-Alumina α-Alumina

Borosilicate glass Pyrolyzed carbon

Zirconia/stainless steel

Zirconia carbon

Membrane Structure and Morphology

Symmetrical

Asymmetrical

Driving Force in Membrane Processes

• Trans-membrane pressure (TMP)

• Concentration gradient

• Chemical potential

• Osmotic pressure

• Electric field

• Magnetic field

• Partial pressure

• pH gradient

• ………

Conventional filtration Microfiltration

Ultrafiltration

Nanofiltration Reverse

Osmosis

10^-10 10^-9 10^-8 10^-7 10^-6 10^-5 10^-4 10^-3 10^-2 Pore Size (m)

Ionic Macromolecular Micron Fine particls Coarse particles Range

Classification of Membrane Processes

Based on Pore Size

Transport Mechanisms Through Membranes

• Bulk flow through pores (microporous with pores larger than the mean free path).

• Diffusion through pores (large enough for diffusion, but small relative to the MFP).

• Restricted diffusion through pores (large enough for some species, but not others).

• Solution-diffusion (Diffusion through dense Ms with diffusant dissolved in polymer matrix).

Solution-diffusion Restricted diffusion (Micro., Ultrafiltration)

Diffusion through pores Bulk flow through pores

Osmosis and Reverse Osmosis

A, B, C P₁

C C A, B, C

P₁

C Membrane

(permeable only to solvent)

A, B, C

P₁ P₂ P₂

P₂

Initial condition (equal pressures)

Equilibrium condition (pressure difference maintained by osmotic P)

Reverse osmosis (Transport against concentration gradient

if pressure above osmotic P)

Pressure Gradient Concentration

Gradient

In reverse osmosis a pressure gradient is used to push solvent through a

membrane which is not permeable to the solute. This pressure must be greater than the osmotic pressure.

Characteristics of Membrane Processes

Membrane process Feed Permeate Motive power

Micro-filtration (MF) liquid liquid Pressure (0.5-5 bar) Ultra-filtration (UF) liquid liquid Pressure (2-10 bar) Nano-filtration (NF) liquid liquid Pressure (5-20 bar) Reverse osmosis (RO) liquid liquid Pressure (10-80 bar) Gas separation (GS) gas gas Pressure (partial)

Facilitated transport (FT) gas gas Chemical Ads. and Pres.

Vapor Permeation (VP) vapor vapor Pressure (partial) Perevaporation (PV) liquid vapor Pressure (partial) Electrodialysis (ED) liquid liquid Electrical potential

Typical Operative Conditions of Membrane Processes

Features Reverse Osmosis Nanofiltration Ultrafiltration Microfiltration Membrane Asymmetrical Asymmetrical Asymmetrical Symmetrical

Asymmetrical

Wall Thickness 150 mm 150 mm 150-250 mm 10-150 mm

Film thickness 1 mm 1 mm 1 mm various

Pore size <0.002 µm <0.002 µm 0.02-0.2 µm 0.2-5 µm

Rejects

HMWC, LMWC, Sodium, Chloride,

glucose, amino acids, proteins

HMWC, mono-, di-, and oligo-

saccharides, polyvalent anions

Macromolecules, proteins, polysaccharides,

virus

Particulates, clay, bacteria

Membrane module

Tubular, spiral- wound, plate &

frame

Tubular, spiral- wound, plate &

frame

Tubular, hollow- fiber, spiral-wound,

plate & frame

Tubular, hollow- fiber, plate & frame

Material CA, TFC CA, TFC CA, TFC, Ceramic CA, TFC, Ceramic, PVDF, Sintered

Pressure 15-150 bar 5-35 bar 1-10 bar <2 bar

Flow 10-50 l·m^-2·h^-1 10-100 l·m^-2·h^-1 10-200 l·m^-2·h^-1 50-1000 l·m^-2·h^-1

Some Membrane Types

Membrana RO

Traditional MF Asymmetrical MF

Very asymmetrical MF Ultrafiltration UF RO Reverse Osmosis

‘Basic Principles of Membrane Technology’, Mulder, M., 2nd. Edt., Kluwer Academic Publishers, 1996

Spiral Flow Membrane Module

• Flat sheet membranes are fused to form an envelop

• Membrane envelop is spirally wound along with a feed spacer

• Filtrate is collected within the envelop and piped out

Side-stream Ceramic Modules

Made in permeable inorganic

material worked in order to

obtain hollows with inside

several pores of variable

forms and sizes.

Caratteristiche d’Uso di Alcuni Moduli

Module Type Characteristic Flat plate Spiral

Wound

Shell and Tube

Hollow Fibre

Packaging density (m²/m³)

Moderate (200-400)

Moderate (300-900)

Low (150- 300)

High

(9000-30000)

Fluid management Good Good High

pumping costs

Good

Suspended solids capability

Moderate Poor Good Poor

Cleaning Sometimes

difficult

Sometime s difficult

Facile Backlashing possible

Replacement Sheets or cartridge

Cartridge Tubes Cartridge

Advantages of Membrane Separations

Kvaerner process for the separation/capture of CO₂ from exhausted turbine gases.

75% weight reduction;

65% size reduction Conventional Process

Membrane Process

Vent without CO₂

In ^Steam Out

120°C Amine without CO₂

Vent with CO₂, 40°C

Steam with CO₂

Ammina con CO2

Amine

Reactive, hybrid and bioseparations

Bioseparations Hybrid Bioseparations

• Bioextraction

• Membrane adsorption

• Distillation & Membranes

• …• …

• Reactive

• Distillation

• Reactive absorption

• Reactive extraction

• Membrane reactor

• Distillation &

Membranes

• Extraction &

crystallization

• Distillation &

crystallization

Reactive Separations Hybrid Separations

Distillation

Absorption

Extraction

Membranes

UOP LLC

Miniaturization of Analytical Systems

Mechanism Tools

LAMIMS MRX

Atm. TSR TEOM

Pulsed

MRX TAP

Reactivity Testing

ZLC

Calorimetry Isotopic

Labeling

SSITKA

Process Model

Reaction Mechanism Heat of Ads.

Capacity.

Number of Intermediates

lifetime a Diffusion

Characterization UOP LLC

References on Process Intensification

• A. Górak, A. Stankiewicz, G. Wild Chemical Engineering and Processing:

Process Intensification, Chemical Engineering Progress, Elsevier, 2010;

ISSN: 0255-2701

• Van Gerven, T.; Stankiewicz A. Ind. Eng. Chem. Res., 2009, 48, 2465–2474.

• Stankiewicz, A and J.A. Moulijn, Process Intensification, Ind. Eng. Chem.

Res. 2002, vol. 41 pp 1920-1924

• Kletz, T.A.,’ Process Plants – A Handbook for Inherently Safer Design’, Taylor and Francis, London

• Jenck, J.F., Agterberg, F., Droescher, M.J.; "Products and processes for a sustainable chemical industry: a review of achievements and prospects", Green Chem. 6 (2004), 544-556

• Ramshaw, C.; "Process Intensification and Green Chemistry", Green Chem. 1 (1999), G15-G17

• Jachuck, R., Process Intensification for Responsive Processing, Trans IChemE, vol. 80, Part A, April 2002.

Microchemical and Microphysical Systems

PhD

IN INDUSTRIAL CHEMISTRY AND CHEMICAL ENGINEERING (CII)

Prof. Attilio Citterio

Dipartimento CMIC “Giulio Natta”

http://iscamap.chem.polimi.it/citterio/dottorato/

Micro-chemical Systems: Opportunity and Limits

yield

energy efficiency compact

Miniature reaction and other unit operations, possessing specific advantages over conventional chemical systems

Simplified Vision!

FINE-CHEMICAL MICROREACTOR PRODUCTION PLANT

Micromixer (1000 l/h)

Microtube reactor (100 l/h)

Micro heat exchanger (100 l/h)

Fine-chemical plant with 10 microstructured

production devices: launch at ACHEMA, May 15, 2006

IChemE Chemistry Innovation KTN/Impact Award

TU/e Nomination to award ceremony for presenting TU/e-IMM

development (Whitehall, London)

IMM Plant in NATURE Nature 442, 27 July 2006

Chemical Reactor Scale

Industry Laboratory Micro-system

Volume 30 m

10

m

3 10

m

Scale-down 1 1:3 10

1: 10

Diameter 2 m 2 cm 20 µm

Surface Volume

2 m

m

200 m

m

200 000 m

m

Key Benefit:

Surface to Volume

constant volume

Radii (µm) Surface area / Volume (µm-1 )

0 0.2 0.4 0.6 0.8 1

10 20 30 40 50 60 70 80 90 100

0

A B C

V constant

SA increase

Surface to volume ratio

• Heat management

• Mixing

• Reactions Surface

• Explosion-Safety

Temporal Scale and Typical Length of Chemical Reactors

1 m 10 m 100 mm

10 mm 100 µm 1 mm

10 µm 1 µm

10^-2 10^-1 10⁰ 10¹ 10² 10³ 10⁴

length

mean residence time [s]

micro-structured apparatus

milli-structured apparatus

multi-tube reactor

tube reactor

Stirred tank reactor

Characteristics of Micro-structured Reactors

Channel diameter: ~50 – 500 μm Channel length: 20 – 100 mm No of channel: 200 – 1000

Specific surface: 10⁴–10⁵ m²/m³

Micro-structured Components are Available

Surface to Volume: Superb Transport

Example: overall heat transfer coefficient

Hx Type U (W·m^-2·K^-1)

Tubular 150-1200

Spiral 700-2500

Plate 1000-4000

Micro-channel: 3800-6800

(500×500 µm² × 1.5 cm channels)

A New Class of Process Technology

1 Å 1 nm 1 µm 1 mm 1 m 1 km

Smog

Gas Molecules

Viruses

Bacteria

Human Hair Radius of Most Cells

Atmospheric dust

Tobacco smoke Beach Sand

Man

Single Transistor on IC IC Chip Personal Computer

Conventional Pumps and Valves Conventional Reactors and Heat Exchangers

Conventional Thermal and Chemical Plant Micromotor Rotors

Typical Microchannel widths

Micro Pumps and Valves

Microchannel Reactors and heat exchangers

MicroThermal and Chemical Systems

Properties of Micro Devices

• Fluid behaviour at this scale



Wall effects dominate

• Surfaces and interfaces



Fouling



Multi-phase flow



Surface energy, tension, wettability



Dynamics -- start-up

• Equipment



Basic state measurements - P, T, phase, quality, composition



Density, thermal conductivity, electrical conductivity



Controls -- need to be integrated



Fluid flow and distribution



System homogeneity

Features of a Continuous Microreactor System

1. Precise control of temperature – easily set and changed - no temperature gradients

2. Precise control of time - easily set and changed – quick hot reactions for consistent particle size

3. Precise control of feeds/stoichiometry – rapidly investigate stoichiometry by changing feed rates

4. Consistent and rapid mixing – ensures nucleation not precipitation 5. No scale limitations – small scale for

optimisation; or “leave tap

running” to make kilograms per day (100g/hr readily achievable) 6. Reproducible – same temperature,

same mixing, same reaction time, every time

7. Immediate aqueous work up – simple work up available if required

Micro-reactor plant

MICRO-REACTOR PLANT – 5-tube reactor; 4.4 t/a; 10 l/h

45% selectivity; 200°C / 40 bar (‚high-p,T‘) Base case: high-p,T

Cost Portion Key Figure Unit Price

Raw material 25 kg unit 38.30 € / kg

Energy 3 kW 1.36 € / kg

Labour 0.25 manpower 36.36 € / kg

Waste P / W 1 : 18 14.76 € / kg

Operational costs production site 3 m² 0.20 € / kg

Σ Operational Costs 90.98 € / kg

Investment Costs 10 a lifetime; 27,600.00 €

Σ Capital Costs (incl. maintenance) 7a amortisation 1.12 € / kg Costs of Product no separation included 92.10 € / kg Real Sales Price of Product purified product, 98% 123.60 € / kg

Micromixers

Injection of Multiple Microjets

Schematic of a micromixer with injection of

1. The central element of the mixer is a sievelike structure with a large number of regular holes.

2. During operations, the mixing are is filled with one liquid, and the other liquid is injected into the mixing volume through a multitude of microholes.

3. Numerous microjets are generated and increase the contact surface between the two liquids.

4. The holes are positioned in rows 10-100 μm apart, which results in short diffusional paths between the jets.

5. Typical flowrates are in the μL/s, the hole diameter is 10 μm, and the height of the mixing chamber some 100 μm

Microseparators

Schematic of solute exchange between immiscible fluids in partially overlapping

microchannels (left) and scanning electron micrograph of the cross section of the partially overlapping microchannels (right)

Exchange between Immiscible Fluids

Exchange between Immiscible Fluids

Scanning electron micrograph (left) and schematic (right) of an

extraction unit with adjacent channels for two fluids with slits, oblique to the flow direction, for exchange between the two phases

Aqueous

Aqueous

Organic

Organic

Corning Glass Millireactors

Pressure drop 1 millimeter Mixing

300 micron

Heat exchange layer Heat exchange layer Reactants

Fluidic modules: concept and library

Engineered Reactor Components

O-ring seals Connectors

Interfaces

Frames

Fluidic Modules

Standard Fittings

Tubing

Sensors

Instrumentation (Pressure relief valve…)

Add-on

Labelling (insulation…)

Paal Knorr Synthesis via Microreactors

FutureChemistry’s FlowSyn on Micronit Microfluidics microreactors

Diketone

Amine

Quenching agent

Microreactor

Product Temperature control

Collection and off-line analysis P2

P3 P1

M

M RI C

H₃ C

C CH₃ O

O

+ _{H N} ^OH

2 - 2 H₂O

N CH₃

CH₃

OH

Microstructured Epoxidation Reactor

Reaction (microstructured) Mixing (microstructured) H₂O₂ evaporation

(microstructured)

Model Synthesis:

+ H₂O_2(vap)/- H₂O O TS-1

Features:

• Modular (unit operations, capacity)

• Multi-purpose (catalyst and reaction)

• Reaction under pressure

• Reactions in the explosive regime

Degussa

Radical Polymerization

Some Caveats

 Process modification is non-trivial for the chemical industry

 Some strategies tend to shift risks, rather than reduce them

 e.g., reducing inventories may increase transportation

 Even if all risk could be eliminated from chemical manufacturing facilities, other targets exist

 only 18% of facilities required to report under RMP were chemical manufacturing facilities!

 underscores importance of moving towards safer products, not just safer processes

 The “risk vs. efficiency” equation has implications for sustainability.

 beware of “easy answers!”

Where to Apply Microchemical Technology?

 Direct routes from hazardous systems

 Routes at increased concentration or even solvent-free

 Routes at elevated temperature and/or pressure

 Routes mixing the reactants ‘all at once’

 Routes using unstable intermediates

 Routes in the explosive or thermal runaway regime

 Routes omitting the need of catalysts and auxiliary agents

DEVELOPMENT OF REACTORS TO ENABLE CHEMISTRY RATHER THAN SUBDUING CHEMISTRY AROUND THE REACTOR

V. Hessel, P. Löb, H. Löwe, Curr. Org. Chem. 9, 8 (2005) 765-787

Jähnisch, K.; Hessel, V. et al.; Angew. Chem. Intern. Ed. 43, 4 (2004) 406-446

References on Microreactors and Microchemical Systems

1. S. Born, E. O'Neal, K.F. Jensen "Organic Synthesis in Small Scale Continuous Flow: Flow Chemistry" Organic Synthesis in Small Scale Continuous Flow: Flow Chemistry, In Comprehensive Organic Synthesis II (Second Edition), edited by Paul Knochel, Elsevier, Amsterdam, 2014, Pages 54-93,

2. Patrick L. Mills, David J. Quiram, James F. Ryley, Microreactor technology and process miniaturization for catalytic reactions—A perspective on recent developments and emerging technologies, Chemical Engineering Science, 2007, 62, 24, 6992

3. Paul Watts, Charlotte Wiles, Recent advances in synthetic micro reaction technology, Chem. Commun., 2007, 5, 443 4. Nam-Trung Nguyen, Micromixers, 2008, 293

5. D. Ghislieri, K. Gilmore, P. H. Seeberger Control for divergent, continuous, multistep syntheses of active pharmaceutical ingredients” Angew. Chem., I.E. 2015, 54, 678–682

6. C. Y. Park, Y. J. Kim, H. J. Lim, J. H. Park, M. J. Kim, S. W. Seo, C. P. Park “Continuous flow photooxygenation of monoterpenes” RSC Advances 2015, 5, 4233–4237

7. Christoph Tonhauser, Adrian Natalello, Holger Löwe, Holger Frey, Microflow Technology in Polymer Synthesis, Macromolecules, 2012, 45, 24, 9551.

8. P. Wiktor, A. Brunner, P. Kahn, J. Qiu, M. Magee, X. F. Bian, K. Karthikeyan, J. LaBaer “Microreactor array device”

Scientific Reports 2015, 5, Article number: 8736, doi: 10.1038/srep08736

9. Jun-ichi Yoshida, Heejin Kim, Aiichiro Nagaki, Green and Sustainable Chemical Synthesis Using Flow Microreactors, ChemSusChem, 2011, 4, 3, 331

10. Florence Bally, Christophe A. Serra, Volker Hessel, Georges Hadziioannou, Homogeneous Polymerization: Benefits Brought by Microprocess Technologies to the Synthesis and Production of Polymers, Macromolecular Reaction Engineering, 2010, 4, 9-10, 543

11. Jun Yue, Jaap C. Schouten, T. Alexander Nijhuis, Integration of Microreactors with Spectroscopic Detection for Online Reaction Monitoring and Catalyst Characterization, Industrial & Engineering Chemistry Research, 2012, 51, 45, 14583

12. Li-Hua Du, Xi-Ping Luo, Lipase-catalyzed regioselective acylation of sugar in microreactors, RSC Advances, 2012, 2,