Batch Processes

In  the 1950s, chemical engineers might have the impression that  the  ultimate 

mission  of  the engineers  was  to transform old-fashioned batch processes into 

modern continuous ones (Rippin, 1983). With  such a perspective it is surprising to 

find  that, today, fifty years later  a  significant proportion  of  the world’s chemical 

production by volume and a much  larger proportion by  value is still made in batch 

plants  and  it is unlikely that this proportion  will  decline in  the  near  future. 

Parakrama  (1985)  reported  that  99  batch  processes  were  in operation  in  74 UK 

manufacturing companies. Among these, 80% plants were producing chemicals  in 

steady  or  growing markets. Moreover,  many  more products, which could  be 

manufactured continuously,  are in  fact made in batch plants on economic grounds.

Batch production  is  usually carried out  in  relatively standardised types  of
equipment, which can easily be adapted and  if  necessary reconfigured to produce
many other different products. It is particularly suitable for low volume, high value
products such as pharmaceuticals, polymers, biotechnologicals  or  other fine
chemicals for which  annual requirement can be manufactured in few days or  few
batches in an existing plant. The flexibility of  the production arrangements can also
cope with the fluctuations or rapid changes in demand, which is often characteristic
of products of  this type. Other factors (Shah, 1992) which favours batch processing
are:

• increased global competition in the bulk chemicals sector 
• need to produce customer specific products 
• seasonal demands of certain products 

Where small amounts of different products must be produced, it is usually more
economically efficient  to  manufacture them  in  a  common facility such  as
multipurpose batch plant, rather than operating one plant per product.



source: Batch Distillation Design and Operation, by I.M. Mujtaba
University of  Bradford,  UK