Most of chemical reactions encountered in inorganic or organic chemistry involve either release of heat or supply of heat to the reactor where the chemical reaction is in progress. One does not normally come across a chemical reaction which has zero heat effect. Chemical reactions carried out in continuous flow reactors, be it a CSTR or a plug flow reactor, most often require isothermal conditions to be maintained at any given cross-section or at any given point in the reactor under steady state operating conditions in the reactor. For reactions that are exothermic, the heat released from the reaction requires to be extracted in a manner that the temperature of the reaction mass in the reactor remains constant. For endothermic reactions, heat requires to be supplied to the reactor to hold the temperature constant.


Thermal effects are also relevant during dissolution of any chemical in a liquid. Dissolution of sodium hydroxide flakes or concentrated sulphuric acid in water are two of the most common examples where considerable heat is evolved.


The first task towards quantification of thermal energy involved during a chemical reaction or dissolution is achieved on the basis of published data available with respect to standard heats of formation, bond energies, or heats of dissolution. For those reactions where data is not readily available, thermal data requires to be generated through controlled experiments on laboratory scale.


Adiabatic reactor design is one of the core competencies of Chemical Process Engineers. The expertise available with Chemical Process Engineers starts with quantitative estimation of the thermal energy (Kcals) that is expected to be released during an exothermic reaction. The rate of heat transfer required to be maintained across the reactor wall is then computed through computations involving quantification of heat transfer coefficients, temperature difference which is the driving force between the reaction mass temperature and temperature of the cooling medium, and area available for the heat transfer to take place. Chemical Process Engineers develops the algorithm required to solve and compute the iterative relations involved in the computations to optimize the design.


For the design of a new reactor, the most optimum design for the reactor is arrived involving the reactor dimensions, agitation parameters, viz. impeller diameter & impeller speed, dimensions of the jacket or a coil, etc. are determined and produced in the form of a General Arrangement Drawing which then becomes a basis for the equipment manufacturer.


In the case of an existing reactor, Chemical Process Engineers help the end user in determining the set of operating parameters which can then help them in improving the performance of the reactor in terms of reaction time reduction and hence increased productivity from the existing reactor, if possible.

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Manufacturing of any chemical in commercial scale involves mutli-step flow of the input material starting with reaction, neutralization, crystalization or precipitation of solids, filtration, washing and drying, as a typical example.

The first step towards optimization of chemical process requires all the processes involved above to be so tuned up that none of the processes in the chain becomes the bottle-neck which prevents rated production capacity being achieved.

The optimization begins by sizing the various equipment in the chain in a manner that the capacity of a given process equipment in the chain like the Dryer , for example, is so chosen that its capacity matches the output from the equipment upstream, filter in this case. Sizing the Dryer larger than the optimum will result in more idle time for itself and hence loss of capacity with a higher investment, of course. Sizing the Dryer smaller than the optimum will make equipment on the upstream, viz. the Filter unit holding its output till the Dryer is ready to receive the material.

Any mismatch in the plant either during design or during operation, will result in loss of productivity and under-utilzation of the Plant.

Very often in the chemical industry, even if the Plant has been designed optimally and set up, it fails to deliver the targeted quanity and quality merely due to the utilities not matching up with the requirement by process. For example, an exothermic reaction may take longer than what it should ideally take because the circulation flowrate of cooling water through the jacket is not enough to remove the heat at the same rate at which the heat is generated during the reaction.

At Chemical Process Engineers, we specialize in optimization of chemical process in a manner that bottle-necks in the plant are avoided by properly designing and / or selecting the process equipment and utilities, most often through a calculated approach using principles of fluid flow, thermodynamics, heat and mass transfer.

For a more specific understanding of our approach with regard to design of a batch type chemical reactor, read through our blog on optimization of batch chemical reactors.

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