Batch control maximises efficiency

Paul Gay takes a look at the batch control market to find healthy growth while control engineering work at Kodak demonstrates some advantages of recent batch techniques

The worldwide market for Batch Control Systems (BCSs) is growing faster than the overall process control market, according to a market study just released by ARC Advisory Group. And because the pharmaceutical, fine chemical, and consumer goods industries are currently enjoying a period of expansion, there is an increased awareness of the benefits of batch control and the availability of cost-effective solutions.

Europe, including Middle East and Africa, is apparently the largest market representing over 40% of the total worldwide market for BCS. Furthermore the ISA-S88 batch control standard is increasing understanding in less sophisticated users, making them more receptive to automation.

High labour costs and increased environmental regulations are the primary reasons for the low level of industrial investments and growth in Western Europe. Achieving and maintaining profitability is the goal of every enterprise. Whether the product is a commodity that can be manufactured anywhere in the world, or a specialty product, well-implemented cost controls will produce more profit for Kodak’s shareholders.

Manufacturers are turning to flexible batch process control and on-line schedule update to maximise production efficiency. Large, sophisticated users are now demanding comprehensive, integrated batch control solutions with seamless interface to production management and business planning systems. Manufacturers of pharmaceuticals and fine chemicals are building flexible plants where many different products may be manufactured, and product changes can be made more quickly and easily. This is creating demand for more automated BCSs.

A HARROWING TASK

Programming process control systems does not have to be the job of the software engineer. Many plant managers argue that no one is better placed to develop a control system than the process engineers themselves.

Image company Kodak has a plant at Harrow which is one of a number of the company’s manufacturing sites world wide which share common process control systems. The Kodak philosophy for batch and continuous process lines is to develop a solution at one location, before replicating worldwide.

Implementing a batch control system at Harrow was no easy task for Kodak’s engineers. The process is highly sensitive and cloaked in secrecy, so much of the development work on the control system was carried out in house. Globalising this type of batch control isn’t particularly straightforward either. With plants in the UK, France, Brazil, Australia, Mexico and the USA, there is the local language to consider. Above all, any recipes, software control or reporting systems must be transportable to any site, because the chemistry involved in film manufacture, and the consistency demanded by customers, requires complete repeatability.

THE FILM PROCESS

The model used for the film making process, which formulates the light sensitive coatings, was developed in the US using TIStar and PLCs to control semi-continuous operations. In the UK an old, and discontinued, Kent Taylor MOD300 system was used to control the process. Whilst providing reasonable reliability, the MOD300 was becoming harder to maintain because of spare parts’ availability. So a decision was made to replicate the process control system operating in the US and upgrade to the latest PCS7 technology once this had been adopted in the US plant. Two Unix TIStar systems, using Simatic 565 and 505 PLCs, with distributed I/O, have been installed. The first replaces the MOD300 equipment and the second controls a new manufacturing line.

Flexibility is very important for Kodak, because one site may develop an improvement to the process which then needs to be rolled out across the world. To ensure that each site knows how the others are performing, data acquired from the Siemens PLCs is available via Siemens own TIway network and an Ethernet link. PCs at the Harrow site communicate with other plants, where data can be reviewed and analysed. Trends in production yields, cycle times and process parameters such as temperature can all be monitored remotely. This gives the main US plant the opportunity to audit performance but also enables plant managers in Mexico to discuss results with colleagues in France, for example.

Process chemistry, especially that employed to produce film coatings, is a precise science. However, success still relies upon the knowledge and experience of the workforce. Occasionally, odd things happen during the blending or reaction phases. If an on site maintenance engineer can assess the situation and take the necessary steps immediately, thousands of pounds of lost production can be saved. Any problems with batch control also have a knock on effect downstream, where film making is a truly continuous process which needs a consistent chemical supply.

Worldwide Batch Control System Outlook from ARC Advisory Group at $4,500.

Tel: Jan Carman +1 (781) 471-1149 Website: http://www.arcweb.com