Page 19 - CW E-Magazine (Oct-Nov-2023)

Flow Chemistry

Sustainability through continuous manufacturing:

Necessity, urgency, opportunities and challenges

Preamble:
he beginning of the chemi-
cal industry in India happened
Tthrough the indigenous efforts by
Prof. P.C. Ray (Calcutta Univ.) through
Bengal Chemicals and Pharmaceutical
Works in 1892, followed by start of a
few more exemplary chemical indus-
tries, viz. Alembic Chemical Works
(Vadodara), Unichem, Chemo Phar-
maceuticals, Zandu Pharma Works,
Chemical Industrial and Pharmaceuti-
cal Laboratories (CIPLA), and East
India Pharmaceutical Works, all before
the country got freedom. As of now, the
number of chemical industries in India
is over 11,000 and the market size of ing platforms that are highly intensi- ner, known to chemical engineers for
the chemical and petrochemical sector fied, continuous, minimal to zero dis- ages. Unlike batch operations, where
in India is US$178-bn. (refs.: Invest charge, compact, green, solvent-free the composition of the reaction mass
India). In the recent past, a lot of im- etc. While these aspects are not easy to and hence the heat demand continues
petus is being given on the possible op- achieve immediately, a steady develop- to change with time, making it an un-
portunities for Indian chemical industry ment will definitely happen. steady operation, a continuous opera-
to be one of the options for China or tion is always at a steady state and de-
to reduce our import dependence or to Considering the projected growth livers a consistent product quality at the
be self-sustained in certain areas, viz., of the Indian economy and per capita outlet for a given set of inlet composi-
pharma, which is almost like a strategic income, the specialty chemical industry tion, temperature set along the length of
sector when it comes to health of the is expected to grow at a higher rate than reactor, mixing and the extent of mass
entire population in our country. before (also because of a growing and transfer (for multi-phase reactions).
demanding population). It is essential Continuous flow synthesis gets away
In the last two years, a large number to enhance innovation and competitive from the batch-to-batch variations and
of new expansions (brown field) and performance of this sector in order to thus is an excellent processing option
many new green field chemical plants position Indian specialty chemicals on for small as well as large volume chem-
have got approvals from the Ministry the global map and to meet the ever- ical manufacturing.
of Chemicals and Fertilisers and its af- growing needs as well as expectations
filiated departments. These come from of a prospering society. In CFS, reactants are continuously
a wider range of APIs, intermediates pumped through a reactor under con-
for agrochemicals, dyestuff intermedi- In this article we focus on necessity, trolled conditions, allowing for precise
ates, fragrances, etc. Our industries are urgency, opportunities and challenges control of reaction time, temperature,
making long term plans and exploring in adapting continuous manufacturing. and other reaction parameters and the
possible ways to meet the desired pro- reactions happen in a flowing stream
duction capacities, secure raw materi- Some information on continuous of reactants. Some key benefits of flow
als through long term contracts, ensure flow synthesis (CFS) chemistry include increased reaction
processes in green field plants are safe CFS, flow chemistry, continuous efficiency, reduced waste generation,
and with reduced carbon footprint, etc. manufacturing, etc. are synonyms of and improved safety. Additionally, flow
However, it is now necessary to move the concept of carrying out a reaction or chemistry can facilitate the synthesis of
towards more sustainable manufactur- any unit operation in continuous man- complex molecules that are difficult to

Chemical Weekly October / November 2023 15