Bitter-sweet result

Of all the ingredients on a cocktail-mixer's shelf, bitters are perhaps the least known and appreciated. Often highly alcoholic and — on their own, at least — completely unpalatable, they are added in dashes and drizzles to put a characteristic edge on a cocktail's flavour. They come in small bottles with crowded, mysterious labels, last for ages and have the longest, most closely guarded histories of any alcoholic drinks, with ancient recipes and complex techniques for infusing herbal flavours into alcohol.

owns several brands of bitters, but like most large spirit-makers, it would rather eschew complex and archaic processes for predictable and automated ones. But it can only do this if the flavour of its products remains consistent. When it decided to transfer production from a blending plant in Dalby, Denmark, to an extended modern facility in Aalborg, it had to rethink how it made bitters.

The processes involved in making bitters include: extraction, distillation, cooling and filtration, along with the logistics and utilities functions of truck loading and unloading, tank-farm management and steam generation. At Dalby, these had been performed using 'islands' of automation, controlled by a few PLCs and a SCADA system, with extensive use of manual processes.

But for Aalborg, the company wanted to automate as much as possible. The system had to be scalable to accommodate future expansion; and it had to run from a single database, to simplify the management of the plant and process control, improve the accuracy of recipes and simplify maintenance and upgrades. To carry out the work, the company turned to a longstanding automation partner, Emerson Process Management.

The Aalborg plant's main raw-liquor production section used a distributed control system (DCS) from

to monitor and control steam generation, fermentation and distillation of raw spirit, and carbon-dioxide generation and storage. The system was due for replacement and this gave Pernod Ricard the opportunity to extend it to cover bitters production as well. 'This RS3 DCS has been extremely reliable and the support we have received over the years enabled us to confidently choose the DeltaV system for this important project,' explained plant manager Claus Nielsen.

The DeltaV system incorporates most of the functions of the old RS3 system and is highly scalable; it can go from a single I/O to hundreds or even thousands. For the bitters production line, it integrates with much of the old blending machinery from the Dalby plant, but with a completely new process-control architecture.

The blending facility contains about 130 separate tanks. The level, temperature and flow of liquids in and between these tanks is monitored by an array of pressure transmitters, vibrating fork switches and Coriolis mass flow meters, the high repeatability and accuracy levels of which make them suitable for custody-transfer applications where the quantity of alcohol leaving the plant is subject to legal controls. This allows the plant to produce a variety of bitters from different recipes, all of which are stored in the DeltaV system's database.

This, in particular, has helped the company accelerate production of batches of bitters. At the old plant, recipe setpoints had to be manually entered into the PLC from paper recipes, but the new system holds all the recipes, process instructions, programmes and set points on the system together, making them easier to implement and faster to complete.

'Our process has been optimised by installing the new automation architecture,' Nielsen said. The processes now produce less waste, and product consistency has been improved because of a reduction in human error. Man-hours are also down, Nielsen added. 'We were delighted with the outcome of the new blending facility,' he said. 'The Emerson solution has been very successful. We received excellent support and have recently selected Emerson for another expansion project at the site.'

Emerson also recently helped a process-equipment company to improve its products, providing Coriolis meters to an Italian manufacturer of centrifuges to ensure its products produce skimmed milk, cream and yoghurt to consistent densities.

Seital Separatori produces centrifugal disc separators that remove cream from milk. Consistent results are important for this application, as excess fat left in milk costs the producer money; an accurate machine can pay for itself in a little over a year.

Emerson supplied the company with Micro Motion Elite CMF100 Coriolis meters, which measure mass flow and density, for a separator to be used in a yoghurt-making process. This had to provide milk with a fat content of 3.5 per cent, with an accuracy of 0.02-0.03 per cent.

'We considered a number of manufacturers and compared the performance of their products,' said Seital director Giancarlo Sopelsa. 'In terms of mass flow and density measurement, the Emerson instruments have the highest accuracy on the market.'

To provide the fat concentration, Emerson had to determine its relationship to the parameters that could be measured, the density and temperature of the milk. 'We had a very good response from Emerson, which shared the problem of finding the fat concentration based on the density value, which was slowing down the development of the machine,' Sopelsa said. 'After just a few tests with the instrumentation we were able to implement a formula to generate these values.'