Emphasised role of PC in batch process control

For decades the efficiency of chemical industry was drawn from large-scale continuous processes. Typically, a first version of industrial manufacturing line for a new chemical was a bigger scale laboratory process, which usually was a batch process. Since high economies of scale was seen as the keyword to successful business the attention in chemical engineering was focused on investigating and developing continuous processes. However, the increased emphasis on fine and speciality chemicals, customer service and product quality have highlighted the benefits of batch processing and, currently, about 50% of processes are batch processes. Continuous processing remains dominant in bulk chemicals. There are certain technical and economical factors which clearly favour the use of batch processes. Firstly, batch processes often consists of ordinary processing units (e.g., stirred vessels) that are easy and fast to design and fabricate. They are also easy to modify for new products. Secondly, a single unit may be multipurpose, i.e., it can be used for several processing phase of a batch, and in general, such a factory easily supports multiproduct manufacturing. Thirdly, the technology is easy to scale up according to market conditions. Fourthly, a batch plant is much more robust than a continuous plant.