Impressive agility

In the process industries, strict regulations faced by pharmaceutical, food and chemicals manufacturers have made firms unwilling to modernise tried and tested manually-run processes. But this is set to change. New `agile manufacturing’ control systems are promising such large cost improvements that processors will find them hard to resist. Batch processes produce a quantity of […]

In the process industries, strict regulations faced by pharmaceutical, food and chemicals manufacturers have made firms unwilling to modernise tried and tested manually-run processes. But this is set to change. New `agile manufacturing’ control systems are promising such large cost improvements that processors will find them hard to resist.

Batch processes produce a quantity of a product in a set sequence, and tend to be used for small-volume, high-value products such as pharmaceuticals or foods. It is a labour-intensive type of manufacturing, with operators needed to control changes in the production environment from one operation to the next. For example, a reactor filled with the product may first have to be heated and then cooled in two distinct operations.

The World Batch Forum, an industry group promoting automation, says batch plants offer huge scope for savings. It calculates that operator actions could be reduced by 80%, cutting wage bills and making processes safer by reducing the opportunity for human error. With tighter control of process conditions, it says the number of faulty batches could fall by 90%, product quality could improve by 40% and yields rise by 10%.

The group also claims batch automation could bring a 2% cut in the cost of raw materials and reduce production time for a batch by about a third. Overall, these changes could be worth $240,000 annually to a small batch manufacturer.

But firms have been reluctant to adopt automated control technologies for two main reasons. First, gaining approval to modify a continuous process plant can be time consuming and expensive, especially in the US. Second, the capital cost of new equipment is often prohibitive, given that most batch processes are small operations.

However, cheaper microchips and advances in computer technology are now allowing control system makers to tailor equipment to smaller producers. Systems are available using inexpensive PC-based Windows NT servers instead of costly bespoke workstations.

The publication three years ago of an international standard, ISA 88, has boosted industry confidence and increased the take-up of the technology. It has established a common language allowing different control systems to communicate.

Chris Morse, engineering group leader at Honeywell Industrial Automation & Control, describes the previous generation of batch plant control systems as `monolithic’.

`Changing procedures or altering a batch recipe involved changing old, inflexible Fortran programs,’ he says. `With agile, automated systems you can engineer modifications much more easily without having to write a line of programming.’

In many manually controlled batch processes, operators have to follow a reaction through altering flows and temperatures against a clock. To do so, they might have to walk from one side of the plant to another to manipulate a control.

Morse recalls one case when an automation system cut the cycle time of a batch process from 34 hours to 16 hours. `The operator had to walk around the plant, adding dead time to the process. The company didn’t even recognise this until we pointed it out,’ Morse recalls.

Installing an agile batch control system also gives a firm the chance to modularise its plant, so operations such as mixing and heating can be reorganised and the process sequence changed. For small-volume batch manufacturers, the potential gains are huge, as the elements of the plant can be swapped around to manufacture different products. This optimises resources and reduces costs.

Automated batch systems also offer big data handling advantages. `Many batch processes are poorly understood,’ says Morse. `Modern systems give users the ability to gather information and analyse it using their PC. This can lead to a greater understanding of how parameters such as the profile of reactor temperature versus time can affect product quality. The process can then be optimised.’

Effective data handling is essential for gaining regulatory approval for pharmaceuticals. In the US, Federal Drug Administration inspectors can arrive on site and demand to see an item of historic process data in under 15 minutes, a test used to prove good process management and the ability to trace faulty batches. For manual, printed systems, retrieving information in such a short period is a challenging task.

Morse admits there are still a lot of human hurdles to overcome in getting UK batch processors to adopt the technology. Honeywell has sold its PlantScape system to less than 100 plants so far.

But he is confident about the prospects for the technology and envisages systems in which a customer’s order triggers an automated chain of events from the company’s sales computer, through its manufacturing plant to its suppliers. Honeywell is working with German enterprise resource planning software firm SAP to achieve this.

`It is fair to say that there are not too many people involved in developing the technology today, but I believe we have the expertise already to achieve fully automated processes,’ says Morse.