Meeting the process CHALLENGE

The challenges facing designers of integrated process systems appear to be becoming even more difficult, as demands for increased hygienic, environmentally acceptable and economic procedures are expected from processing companies. Nowhere is this more difficult than in duties where requirements oppose each other: hygienic processing means effective cleaning, which in turns creates more waste material that has to be disposed of.

Then there are the economic considerations. Making the most of raw materials through effective plant management and control is encouraging the uptake of sophisticated programmable controllers based on systems such as Profibus, ModBus and CANBus. But as yet, there is no common standard on fieldbus technology, with Europe and the US pursuing different technologies.

Exacting levels of hygiene have always applied in pharmaceutical manufacturing, so it has been necessary for companies supplying this industry to manufacture plant and equipment that can be easily cleaned. However, similar demands are now being made in food processing and even toiletries.

All processes require that there can be no cross-over or contamination of materials, so once a product has been manufactured, the processing equipment has to undergo extensive and thorough cleaning. The problem here, though, is that these procedures produce more waste material that has to be treated before it can be disposed of. And effective treatment does not necessarily come cheap.

One answer is to employ processing equipment that has been designed to use all materials effectively, thereby reducing the possibilities for any residue, and accommodate rapid cleaning. Metering pumps fitted with PTFE diaphragms meet these requirements.

Where waste material results from a particular processing method, companies are faced with the problem of its storage and eventual disposal. The answer to this dilemma is to find ways of re-introducing the material into the process stream, thereby maximising the use of potentially expensive materials and reducing waste.

International process systems company Bran + Luebbe advocates that a logical approach to planning processing operations is probably the best way of satisfying conflicting demands. Only through careful analysis of the complete production process can cost-effective systems be designed. Rather than make up one specific product, remove any residue, clean the equipment and start on the next product - as is standard practice in a great many industries - Bran + Luebbe believes that it makes more economic sense to formulate a base solution for the optimum number of products at the outset. Individual products can then be produced by adding speciality chemicals, colours, flavours and so on downstream. This is very economical in the food and toiletries industries. By adopting this approach, the base solution is used to its full potential and plant cleaning and the production of waste material and effluent minimised.

Control is the key

Only through effective control of each and every stage of the production process can accurate and repeatable results be achieved. This is by no means unattainable, as the technology for product profiling and identification at critical stages of the process and remote control of key components via fieldbus systems is now available.

Recent developments in on-line near-infrared spectroscopy allow production personnel to verify the suitability of materials not only prior to their introduction to the process, but also throughout the entire operation. Electronic control of components ensures total accuracy and that set parameters are adhered to.

It is these types of technologies that have lead to a move from traditional batch processing to continuous processing and greater economies of production. Furthermore, they accommodate product identification and traceability, which could previously only be attained with batch processing and which also required date stamping.

There is also one other aspect of the continuous processing that should not be overlooked, and that is the ability to analyse and monitor waste matter and effluent on-line. Having results in real-time allows rapid treatment prior to disposal, or possible recycling of materials.

Effective closed-loop processing relies upon the suitability of the components for the actual application. Components such as dosing pumps, mixers, blenders and analysers must have been developed in conjunction with engineers actually involved in the production processes, as they appreciate the market forces that influence their industries.

Bran + Luebbe is in something of a unique situation, as it is not only involved in the development of processing equipment for specific processing requirements, it is also a systems manufacturer. Market forces are now demanding intelligent components that will integrate with smart systems. Simply setting the stroke length on a dosing pump and letting it run for a set period is no longer a viable option. Where cost-effective, efficient and safe processing is demanded, only total control of the operation will suffice. PE

Chris Riseley is Systems Division Manager with Bran + Luebbe