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Topics in Current Chemistry (2018) 376:44
5 Challenges and Remarking Conclusions
In this review, we have given an overview of the most important engineering principles that are relevant for chemists and chemical engineers to carry out polymerization in flow. Fundamental engineering aspects such as mass transport phenomena
and energy dissipation in continuous-flow microreactors for polymerization processes were clearly explained to distinguish from small-molecular reaction systems.
Some formula deduction was performed regarding the complexity of polymerization processes. A large number of polymerization examples in microreactors and its
comparison with conventional batch reactors would allow someone to thoroughly
understand the relevant engineering principles behind polymerization processes,
which is beneficial for reactor design and process optimization. Moreover, the classification of these examples indeed is good for guiding the construction of a continuous-flow microreactor setup for a specific polymerization process if a reader has
such demand. It is our hope that this review will act as a useful tutorial tool for
researchers and industrial practitioners to recognize what are the selection principles
and when continuous-flow microreactors are suitable for polymerization processes.
Microreactor technology has been developed more vigorously than ever before,
and its achievements in various fields are widely acknowledged. Commercially
available microreactors and accessory equipment have been developed by both
famous academic research centers and transnational corporations according to market requirements. Application examples of this technology on pilot scale and even
industrial production scale have been reported in the chemical and pharmaceutical
industries. Therefore, it is firmly believed that the practical application of microreactor technology on fine chemical industry will become much more popular in the near
future.
However, prosperous development of microreactor technology does not mean that
there are no challenges associated with this technology. In particular, polymerization processes show distinctive features such as high fluid viscosity, occurrence of
autoacceleration effect, and frequent involvement of solid products, which result
in more difficulties in the mixing and dispersion of reactive fluids, lower transport
properties, and even the channel clogging in microreactors. Therefore, comprehensive studies on fundamental engineering principles such as fluid dynamics and
transport phenomena related to the polymerization in flow are still highly desired.
Membrane-dispersion microstructured reactors that can provide numerous droplet swarms with the diameter even less than 5 μm have been demonstrated for its
application on heterogeneous polymerization [12, 83, 182]. Moreover, polymerization kinetics in microreactors is seldom reported, and the selection and design of
microreactors for polymerization are typically performed without the use of reaction
kinetics data or with the use of those from batch reactors. Nevertheless, the polymerization kinetics obtained from batch reactors sometimes is very different from that
from microreactors, limiting its application for the microreactor design. The integration of online characterization and automation techniques in the microreactor setup
represents an important direction to obtain feasible solutions for the precise control over polymerization processes and for studying its relevant complex reaction
185
Reprinted from the journal
Topics in Current Chemistry (2018) 376:44
5 Challenges and Remarking Conclusions
In this review, we have given an overview of the most important engineering principles that are relevant for chemists and chemical engineers to carry out polymerization in flow. Fundamental engineering aspects such as mass transport phenomena
and energy dissipation in continuous-flow microreactors for polymerization processes were clearly explained to distinguish from small-molecular reaction systems.
Some formula deduction was performed regarding the complexity of polymerization processes. A large number of polymerization examples in microreactors and its
comparison with conventional batch reactors would allow someone to thoroughly
understand the relevant engineering principles behind polymerization processes,
which is beneficial for reactor design and process optimization. Moreover, the classification of these examples indeed is good for guiding the construction of a continuous-flow microreactor setup for a specific polymerization process if a reader has
such demand. It is our hope that this review will act as a useful tutorial tool for
researchers and industrial practitioners to recognize what are the selection principles
and when continuous-flow microreactors are suitable for polymerization processes.
Microreactor technology has been developed more vigorously than ever before,
and its achievements in various fields are widely acknowledged. Commercially
available microreactors and accessory equipment have been developed by both
famous academic research centers and transnational corporations according to market requirements. Application examples of this technology on pilot scale and even
industrial production scale have been reported in the chemical and pharmaceutical
industries. Therefore, it is firmly believed that the practical application of microreactor technology on fine chemical industry will become much more popular in the near
future.
However, prosperous development of microreactor technology does not mean that
there are no challenges associated with this technology. In particular, polymerization processes show distinctive features such as high fluid viscosity, occurrence of
autoacceleration effect, and frequent involvement of solid products, which result
in more difficulties in the mixing and dispersion of reactive fluids, lower transport
properties, and even the channel clogging in microreactors. Therefore, comprehensive studies on fundamental engineering principles such as fluid dynamics and
transport phenomena related to the polymerization in flow are still highly desired.
Membrane-dispersion microstructured reactors that can provide numerous droplet swarms with the diameter even less than 5 μm have been demonstrated for its
application on heterogeneous polymerization [12, 83, 182]. Moreover, polymerization kinetics in microreactors is seldom reported, and the selection and design of
microreactors for polymerization are typically performed without the use of reaction
kinetics data or with the use of those from batch reactors. Nevertheless, the polymerization kinetics obtained from batch reactors sometimes is very different from that
from microreactors, limiting its application for the microreactor design. The integration of online characterization and automation techniques in the microreactor setup
represents an important direction to obtain feasible solutions for the precise control over polymerization processes and for studying its relevant complex reaction
185
Reprinted from the journal