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Special Report Special Report

suffi cient as well as poorly trained tinuous process and its process engi- the heat duty along the reactor interlocks. The process control Operational challenges sing than the conventional routes that
manpower, and reluctance to move neering requires the following infor- length and to predict the perfor- systems are designed for safe-ope- Operational issues while executing any are used for decades. Economics does
into digital space through automa- mation to be developed right from the mance for a reliable design. The ration of the plant in order to avoid batch protocol into a continuous proto- play a role, but having a better process
tion at all scales. Quality of training laboratory scale: (i) Physicochemical kinetic models can be solved using deviations from the hazards occur- col are seen in the following: (i) Having cannot beat anything else in the long run.
is also not at par and that leads to properties, (ii) Characterization of raw MATLAB, Python solver tools, etc. ring in the plant using interlock sys- trained manpower, (ii) establishing a Investing at early stage in R&D has helped
widening of the skill gaps further. materials & catalysts, (iii) Flow pro-  Generation of vapor-liquid equili- tems. Further, the control systems fl ow lab with minimal necessary facili- many industries and has its own benefi ts.
 Limited collaboration between in- perties of the materials, (iv) Reaction brium (VLE) data: VLE data is are advancing towards artifi cial ties, (iii) ability to foresee and plug leaks Especially, for CFS, many of these early
dustry and academic institutes/ kinetics, (v) Vapor-liquid equilibrium required for the design of gas-liquid intelligence-based technologies that (which are imperative with so many practitioners now enjoy monopoly in spe-
CSIR labs has also seen long term (VLE) data, (vi) Detailed process fl ow or liquid-liquid separation equip- reduces human efforts. connections), (iv) selection of the right cifi c products as others cannot even come
impact. R&D takes its time and that diagram (PFD), (vii) Piping & instru- ment, mainly distillation and evap-  HAZOP and What-if analysis: components for building a set-up, (v) close to their production costs and yields.
needs to be allowed as creativity mentation diagram (P&ID), (viii) Pro- oration. VLE data can be measured HAZOP studies and What-If analy- developing an operating protocol (viz.
cannot happen in hurry. But, at the cess control strategy & interlocks based or even obtained using different sis have utmost importance in the for CSTRs in series before starting the Summary
same time, time-bound execution of on lab scale observations, and (ix) process simulators, viz. Aspen Plus. process for a success chemical pro- pumps all CSTRs must have a solvent CFS or fl ow chemistry or continuous
projects make the other side more HAZOP and what-if analysis. Selection of appropriate thermody- cess. These need to be taken seri- and one must be patient enough to col- manufacturing has its own benefi ts and
accountable and reliable. namic models are necessary step ously at the lab scale as the scale lect it as waste while the system reaches industries must take them seriously. Even
 Lack of strict IPR implementation The reactions are classifi ed based on for separation of components in of hazards increases exponentially steady state), (vi) developing trouble- early stage theoretical analysis helps to
is something that is almost missing the phases that exist during the course of the chemical processes. Non-ideal as the scale of operation increases. shoot procedure (viz. for clogging, han- overcome the hesitation to choose this
except in some areas (pharma and the reaction: (i) gas-gas, (ii) gas-liquid, behaviour of the gas-liquid phases This is quite essential for a con- dling of solids, evaporating gases, sticky direction. A few important challenges
to some extent in the agrochemical (iii) gas-solid, (iv) liquid-liquid. (v) liquid- should be taken into account with tinuous operation as it directly dic- materials etc.), (vii) fl ow distribution in exist and systematic approach invol-
sectors). solid. (vi) solid-solid, (vii) gas-liquid- residual properties/activity coef- tates the control and interlocks. It large number of parallel reactors, (viii) ving a team of chemists and chemical
 Role of patron bodies is ambiguous solid, etc. and, in general, the necessity fi cients for gas and liquid phases. is necessary to have a quantitative absence of SOP of integrated system, engineers can overcome all of them. The
with respect to new products and to explore kinetics and rates of various This exercise avoids back and forth HAZOP done and verifi ed through (ix) having stand-by and spare items early stage screening approaches deve-
this pushes the industries to largely reactions is not considered by the chemists random experiments to save time. an independent safety team. for components with moving parts as loped by CSIR-NCL often helps to take a
remain in the manufacturing of in- during synthesis. However, for the design  Detailed process fl ow diagram they need more maintenance, (x) dou- quick ‘go/no-go’ decision. Every chem-

termediates, keeping us away from of a continuous pilot plant, such informa- (PFD): It is essential to describe a Classifi cation of challenges and possible ble check on control and monitoring istry needs to be seen differently when
the highly profi table domain of for- tion cannot be missed and hence involv- chemical synthesis in the block fl ow solutions of measurable parameters, and fi nally it comes to transforming a batch process
mulations that go in end use. Excep- ing a chemical engineer in the develop- diagram (BFD) initially, as it helps Once such an approach is deve- (xi) having an in-line analysis. The gen- into a continuous process. A large CRTDH
tions to do exist in this domain too, ment phase is of utmost necessity. Further, to visualize the unit operations loped internally by any fl ow synthesis eral perception that a fl ow synthesis system (DSIR) program for helping the dyestuff
but that is a very small number. the key elements that facilitate relatively involved in process development. team, many of the other challenges can cannot be used for multiple reactions is industry is also in progress and the authors
robust scale-up approach for a process Then, the complete process fl ow be addressed subsequently. These can incorrect and a properly designed system appeal to the industry to approach them to
Approach to overcome some of the include the following unavoidable work diagram (PFD) can be established, be classifi ed into design challenges, can be used for variety of reactions. know the details.
challenges elements. depending on the techno-economic operational challenges and personal/
Development of chemical processes feasibility studies. organizational challenges/barriers. Organizational mind-set related CSIR-NCL is rejuvenating its In-
from lab to pilot-scale and to commer-  Kinetic modelling and simulations  Piping & Instrumentation Diagram challenges dustry Consortium through a Centre for

cial plant needs systematic approach. based on ideal reactors: Kinetics (P&ID): P&ID describes the details Design challenges This aspect is quite important in India. Sustainable Continuous Manufacturing
Industries have been practicing it for of chemical processes plays an im- of the process with automation for Among many important design When it comes to implementing an being formulated jointly by CSIR-NCL &
several decades and have been refi ning portant role in the process design, the smooth operation of the com- related challenges, a few pose signifi cant advanced technology that is still in the CPI (UK) to develop platforms that allow
it from time to time. However, many a development and process intensifi - plete process plant. The process challenges while transforming batch pipeline, often we harbour the attitude of realistic transformation moving up the
times, the problem is resolved after re- cation. Kinetic models are proposed parameters (pressure, temperature, process to continuous. These include: “let someone try it fi rst”; thereby no one TRL ladder. Details of the functioning of
visiting the process at laboratory scale. by various researchers depending rotational speed, etc.) are set using (i) Selection of right components, (ii) wants to be 1st, and no one wants to be this Centre will be announced very soon.
This delays the commercialization and on the class of reactions and corre- instrumentation tools. A programme expertise in designing an experimental too late by becoming 3rd. Such “Neither The future of the Indian chemical indus-
also results in unnecessary ambiguity lations are proposed for kinetic can be set by an instrumentation set-up, (iii) can designing a fl ow reactor 1st nor 3rd syndrome” affects the overall try is in moving to continuous manu-
in success. In view of this, it is neces- regime and diffusional/mass transfer engineer for plant operation in a be as easy as a stirred tank reactor, organizational mindset and kills creati- facturing wherever necessary. There are
sary to develop an ‘in-house’ approach regimes. The simpler reaction distributed control system (DCS) or (iv) what will be the guarantee that the vity. The present hurry in picking up several opportunities and the positive vibes
by every fl ow synthesis team right from kinetic models can be among the other relevant control options. set-up will perform as per the expecta- ready-to-use trained manpower in fl ow indicate that we will not miss this bus.
the laboratory scale. following: (i) power law kinet-  Process control strategy & inter- tions, (v) consistency in fabrication chemistry at higher and higher salaries
ics, (ii) Langmuir- Hinshelwood- locks: The processes designed for and inherent tolerances is quite critical, clearly indicates this approach. Similarly, Disclaimer
The scale-up of a process depends Hougen-Watson (LHHW) kinetics, a specifi c product with desired (vi) choice and clarity of the design basis, every new technology needs some new A lot of information given in this
on various aspects based on chemical and (iii) Eley-Rideal mechanism, purity can be operated continuously etc. A smart team can easily address these investment to be made and often hesita- article is based on various sources
engineering principles. The basic steps etc. The kinetics information is for several hours without manual issues and such examples do exist in many tion is seen even if the laboratory scale from the internet and from interaction
required for the development of a con- important, as it even helps to know intervention using control systems & of the industries mentioned earlier. fl ow synthesis results are far more promi- of the authors with various industries.

170 Chemical Weekly October 31, 2023 Chemical Weekly October 31, 2023 171

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