detailed chemical engineering on this mesoscale level throughout the reactor. If this is
the case, then this polymerization process can be well controlled on the macroscale
level, comprising the polymerization vessel as a whole. By controlling a limited
number of process data, the slurry polymerization process can be operated with
excellent stability over a long time and can be controlled within narrow ranges.
The modern slurry technology process is very flexible in controlling product properties
by using the cascaded reactor technology. This technology involves two or even
three reactors operated in series under different process conditions. The catalyst is
only introduced into the first reactor. The polymerizing particle then passes through
all reactors, producing different types of macromolecules to form a polymer blend
within each polymer grain. A further enormous advantage of this cascade technology
is the high flexibility in product change and product development. Just by changing
process parameters of the different reactors, products with different average molecular
mass, different molecular mass distributions, different copolymer compositions,
and different comonomer distributions can be produced without changing the
catalyst system.
Keywords High density polyethylene Á Process control Á Process design Á Process
modelling Á Product portfolio Á Super-active catalysts Á Ziegler slurry
polymerization
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
2 Super-Active Catalysts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
3 Modeling the Slurry Polymerization Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
3.1 The Microscale Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
3.2 The Mesoscale Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.3 The Macroscale Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
4 Process Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
5 Product Portfolio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
1 Introduction
In 1953, Ziegler and colleagues described a process for polymerization of ethene
at moderately high temperatures and low pressures to generate a new type of
polyethylene, known as high-density polyethylene (PE-HD) [1]. The characteristics
of this process can be summarized as following: in a hydrocarbon diluent
(e.g. diesel oil) under a blanket of nitrogen excluding traces of oxygen and
water, a soluble transition metal compound of the 4th to 6th group of the periodic
table, preferably TiCl 4 , is contacted with an aluminumorganic compound such as an
aluminumalkyl or aluminumalkylchloride to form an active, insoluble TiCl 3 -based
60
L.L. Bo ¨hm
the case, then this polymerization process can be well controlled on the macroscale
level, comprising the polymerization vessel as a whole. By controlling a limited
number of process data, the slurry polymerization process can be operated with
excellent stability over a long time and can be controlled within narrow ranges.
The modern slurry technology process is very flexible in controlling product properties
by using the cascaded reactor technology. This technology involves two or even
three reactors operated in series under different process conditions. The catalyst is
only introduced into the first reactor. The polymerizing particle then passes through
all reactors, producing different types of macromolecules to form a polymer blend
within each polymer grain. A further enormous advantage of this cascade technology
is the high flexibility in product change and product development. Just by changing
process parameters of the different reactors, products with different average molecular
mass, different molecular mass distributions, different copolymer compositions,
and different comonomer distributions can be produced without changing the
catalyst system.
Keywords High density polyethylene Á Process control Á Process design Á Process
modelling Á Product portfolio Á Super-active catalysts Á Ziegler slurry
polymerization
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
2 Super-Active Catalysts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
3 Modeling the Slurry Polymerization Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
3.1 The Microscale Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
3.2 The Mesoscale Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.3 The Macroscale Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
4 Process Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
5 Product Portfolio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
1 Introduction
In 1953, Ziegler and colleagues described a process for polymerization of ethene
at moderately high temperatures and low pressures to generate a new type of
polyethylene, known as high-density polyethylene (PE-HD) [1]. The characteristics
of this process can be summarized as following: in a hydrocarbon diluent
(e.g. diesel oil) under a blanket of nitrogen excluding traces of oxygen and
water, a soluble transition metal compound of the 4th to 6th group of the periodic
table, preferably TiCl 4 , is contacted with an aluminumorganic compound such as an
aluminumalkyl or aluminumalkylchloride to form an active, insoluble TiCl 3 -based
60
L.L. Bo ¨hm