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How a technology can be continuously updated: the EP(D)M experience Gabriele Gatti- versalis Elastomer Process and Technology Manager

Bangkok, November 15th, 2013

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versalis EPM/EP(D)M technology - basics

Versalis technology is based on the slurry process (suspension of rubber crumbs in C3 mix).

A Ziegler-Natta polymerization of ethylene and propylene (copolymer, EPM) is performed in a single continuous stirred reactor. The addition of the third monomer (ENB) allows the production of terpolymers (EP(D)M) with a termonomer max content of 9-10% w/w.

Heat is removed by vaporization of part of the boiling C3 which is then compressed, condensed and recycled back to the reactor.

C3, C2, third monomer recycled and C3, catalytic system, modifier are separately routed to the reactor.

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versalis EP(D)M technology - products

EPM grades are entirely saturated and therefore require vulcanization by organic peroxides.

EP(D)M grades have a residual unsaturation in the side chains and can therefore be cured with sulfur

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Case History - EP(D)M processes – process comparison

EP(D)M are produced using basically three main processes:

Slurry process with Ziegler-Natta catalyst system (versalis)

Wide product mix, mainly for HMW for TPV applications. Line size: 40-50 kta

Not proprietary catalyst. Process available for licensing.

Variable cost: lower than Ziegler-Natta solution

Solution process with Ziegler-Natta catalyst system

Wide product mix, mainly for low ashes requirements. Line size: 40-50 kta

Not proprietary catalyst.

Variable cost: higher than slurry phase

Solution process with Metallocene catalyst system

Few molecular types, narrow MWD, very sensitive to oxidative poisons. Line size: 80-100 kta

Proprietary catalyst.

Variable cost: the lowest compared with the other processes

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versalis EP(D)M technology – block diagram

Monomer(s) purification

Monomers

Finished product (25 kg bales)

Chemicals and catalyst

Polymerization Stripping Finishing Ingredients and catalyst preparation

Plant facilities

Versalis assets – EP(D)M

EPM/EPDM (3 lines) versalis Ferrara, Italy Operation

EPM/EPDM (1 line) versalis Ferrara, Italy Construction

EPM/EPDM (2 lines) JV, Far East Engineering

EPM/EPDM (2 lines) Licensed, South East Asia Engineering

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versalis EP(D)M technology – optimization project

The slurry process is a quite mature technology, with proven advantages in terms of energy consumption compared with the standard solvent process, but some years ago it required a deep rejuvenation.

In 2010 versalis decided to invest time and resources on this process, as the EPM/EPDM market was strongly increasing. The developing team has been commissioned to achieve the following objectives:

increase Plant capacity, focusing on reactor’s throughput and control,

reduce reactor’s fouling and increase service factor,

allow production of extremely soft or hard products,

debottleneck all the Plant’s sections,

update operations, chemicals, technologies, process control with the new opportunities available on the market.

A case history

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Case History: versalis EPM/EP(D)M Reactor and Stripping

Reactor and Steam Strippers are the core sections of the Plant:

Slurry to strippers

Modifier

Propilene, Propane, Ethylene, Catalyst

Rubber crumbs to finishing

Slurry, extender oil

C2, C3 to purification

Steam, additives

Water + ENB to regeneration

REACTOR STEAM STRIPPING

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Case history – First step: advanced process control (APC) to increase quality and capacity

Every optimization can only start after complete knowledge of the real capability of the polymerization technology. In the EP(D)M process, polymerization is complex due to high number of raw materials / chemicals, fed to reactor in different ratios and due to the kinetic model itself.

For this reason it was necessary to develop a system to help Plant’s personnel to anticipate and avoid the fluctuations in product quality due to different reaction conditions.

Thanks to a huge database of all the most important process parameters and the connection with the Lab process control procedure, the APC developed by versalis is able to predict the product properties and allows to be faster to identify the trends and to anticipate the appropriate settings.

APC has increased the first quality production and reduced the time required for every change of campaign, thus enabling Plant to increase service factor and annual capacity.

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Case history – Second step: EPDM reactor optimization and scale-up to increase throughput and quality

A second step was dedicated to the mechanical modification of the EP(D)M reactor that had to be adapted to new products (more mixing required, less fouling accepted) and new capacities (scale-up of the reactor, better service factor)

Analysis of the process variables

Step 2.1: analysis of process variables and present geometry

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Case history – Second step: EPDM reactor optimization and scale-up to increase throughput and quality

Step 2.2: Analysis of the reactor’s sections prone to fouling

Step 2.3: Identification of the products whose properties could be enhanced by a reactor’s modification

CO034

CO038CO043

CO054

CO058 CO059

TER4028

TER4033

TER4038TER4039

TER4044

TER4047

TER4049

TER9046

TER4334

TER4436

TER4437

TER4535

TER6148

TER6235

TER6537

15.0

17.0

19.0

21.0

23.0

25.0

27.0

50 55 60 65 70 75

To

tal S

olid

[%

]

Bound C2 [%]

Impeller rear side

Area close to the agitator shaft

Liquid/vapour intephase

Inner surface of the vessel

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Case history – Second step: EPDM reactor optimization and scale-up to increase throughput and quality

Step 2.4: Definition of the scale-up requirements

New reactor capacity

New design rate

Enhanced time between cleaning

These results shall be achieved working on:

Type of agitation

Monomers feed (rate, geometry)

Cooling capacity

Study has been carried out using 3D models and CFD

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Example of Integrated mixing CFD study – bulk mixing

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Example of Micromixing CFD study

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Case history – third step: EP(D)M stripping and finishing updating

The achieved increase of hourly and yearly capacity required actions on the section of the Plant where reliability and throughput weren’t in line with the new production targets.

Steam strippers have been studied in order to disengagement of the light monomers and the diffusion of the third monomer @ the new target throughput reducing the steam consumption;

Finishing configuration has been deeply modified in order to prevent out-of-spec and mechanical failure which could affect the required smooth run;

Finishing fumes have been selectively collected in order to have the right abatement system for each stream, from the simple water scrubbing to the sophisticated activated carbon treatment to entrap the smelly compounds.

The new EP(D)M lines are sized for an expected capacity of +30% (yearly) of the present ones

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Ongoing …

The pilot Plants at Ferrara, Italy, are working on new products and optimizations

versalis shall increase the product portfolio by introducing a fourth monomer and the relevant new grades.

New developments in catalysis are going to be introduced, to reduce chemicals consumption and enhance products’ quality.

Stay tuned!