Page 23 - CW E-Magazine (Oct-Nov-2023)

Flow Chemistry

confined production due to toxicity and same time, time-bound execution of on lab scale observations, and (ix)
handling issues. Typical domains in- projects make the other side more HAZOP and what-if analysis.
clude electronic chemicals, functional accountable and reliable.
materials for optical and displays, bat- * Lack of strict IPR implementation The reactions are classified based
tery chemicals and energy storage de- is something that is almost missing on the phases that exist during the
vices, strategic chemicals, peptides and except in some areas (pharma and course of the reaction: (i) gas-gas, (ii)
oligonucleotides, high value dyes, etc. to some extent in the agrochemical gas-liquid, (iii) gas-solid, (iv) liquid-
CFS-based system will help move from sectors). liquid. (v) liquid-solid. (vi) solid-solid,
lab to commercial scale much faster in * Role of patron bodies is ambiguous (vii) gas-liquid-solid, etc. and, in gener-
these domains. with respect to new products and al, the necessity to explore kinetics and
this pushes the industries to largely rates of various reactions is not consid-
Challenges remain in the manufacturing of in- ered by the chemists during synthesis.
Transforming an ongoing process termediates, keeping us away from However, for the design of a continu-
into a new platform or starting a new the highly profitable domain of for- ous pilot plant, such information cannot
method of manufacturing with limited mulations that go in end use. Excep- be missed and hence involving a chem-
skill sets is quite challenging. Before tions to do exist in this domain too, ical engineer in the development phase
we discuss the challenges, let’s look at but that is a very small number. is of utmost necessity. Further, the key
some reasons why these challenges ex- elements that facilitate relatively robust
ist. Approach to overcome some of the scale-up approach for a process include
challenges the following unavoidable work ele-
* Inadequate preparedness towards Development of chemical processes ments.
absorption of new technologies be- from lab to pilot-scale and to commer-
cause of significant lag in the tech- cial plant needs systematic approach. * Kinetic modelling and simulations
nologies used in the past, lack of Industries have been practicing it for based on ideal reactors: Kinetics
sufficient information on efficient several decades and have been refining of chemical processes plays an im-
technologies and confidence to ab- it from time to time. However, many a portant role in the process design,
sorb it, wait and watch approach for times, the problem is resolved after re- development and process intensifi-
someone else to adapt it first and visiting the process at laboratory scale. cation. Kinetic models are proposed
lethargy to adapt to changes, even if This delays the commercialization and by various researchers depending
it is evident that there is no way out. also results in unnecessary ambiguity on the class of reactions and corre-
* R&D in a large number of Indian in success. In view of this, it is neces- lations are proposed for kinetic re-
chemical industries suffers from sary to develop an ‘in-house’ approach gime and diffusional/mass transfer
poor investment, using R&D only by every flow synthesis team right from regimes. The simpler reaction ki-
for quality testing, not bringing new the laboratory scale. netic models can be among the fol-
molecules/products (there are excel- lowing: (i) power law kinetics, (ii)
lent exceptions to this) and market- The scale-up of a process depends Langmuir- Hinshelwood-Hougen-
ing-dictated R&D, rather than R&D on various aspects based on chemi- Watson (LHHW) kinetics, and (iii)
for creating new markets/products. cal engineering principles. The basic Eley-Rideal mechanism, etc. The
* The skill gap is widening due to in- steps required for the development of a kinetics information is important,
sufficient as well as poorly trained continuous process and its process en- as it even helps to know the heat
manpower, and reluctance to move gineering requires the following infor- duty along the reactor length and to
into digital space through automa- mation to be developed right from the predict the performance for a reli-
tion at all scales. Quality of training laboratory scale: (i) Physicochemical able design. The kinetic models can
is also not at par and that leads to properties, (ii) Characterization of raw be solved using MATLAB, Python
widening of the skill gaps further. materials & catalysts, (iii) Flow prop- solver tools, etc.
* Limited collaboration between in- erties of the materials, (iv) Reaction * Generation of vapor-liquid equilib-
dustry and academic institutes/ kinetics, (v) Vapor-liquid equilibrium rium (VLE) data: VLE data is re-
CSIR labs has also seen long term (VLE) data, (vi) Detailed process flow quired for the design of gas-liquid or
impact. R&D takes its time and that diagram (PFD), (vii) Piping & instru- liquid-liquid separation equipment,
needs to be allowed as creativity mentation diagram (P&ID), (viii) Pro- mainly distillation and evaporation.
cannot happen in hurry. But, at the cess control strategy & interlocks based VLE data can be measured or even

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