Smarter clean-up

Yorkshire-based speciality chemicals producer AH Marks turned to PICME for help in improving its processes. An 18-month project has seen the company sharply reduce decontamination times for a multi-purpose plant. as Stuart Nathan reports.

AH Marks is the UK’s largest privately-owned chemical manufacturer, and has been operating from its 11Ha site at Wyke, near Bradford, since 1877.

Originally a dyestuffs manufacturer, it now produces speciality chemicals for a variety of markets, including herbicides, performance chemicals, biocatalysts and chiral molecules. Production is on a batch basis, using reactors with capacities from 4500 to 13 500litres. 

Always keen to improve its efficiency, the company took part in the second annual masterclass held by PICME, the Process Industries Centre for Manufacturing Excellence, last year, to try to identify the parts of its operations which could be improved.

PICME’s aim is to help companies improve their efficiency and save money through programmes which use the companies’ existing assets as far as possible, by working alongside their clients’ staff as much as possible, changing operating practices and ‘working smarter, not harder.’

The plant at the focus of the PICME project produces four different products using two different raw materials, explains Malcolm Shaw, who is currently IPPC implementation manager at the site, but who commissioned the plant in 2000. Production is for an external client, which also supplies the raw materials.

‘Because we’re at the mercy of the market and our clients’ orders, we rarely do a full run,’ Shaw says. ‘We may run for one product for three or four weeks, then we have to switch. So we need to decontaminate most of the equipment in the plant, to ensure that we have no impurities when we start making the second product.’

The plant operates using a fully computerised control system, which runs on the basis of recipes.

‘Once the recipe is programmed in, it runs every single part of the plant,’ Shaw says.

This meant that the decontamination could only begin when the entire plant was clear of one set of reagents and products.

‘We then devised a way so that we could start decontaminating while the plant was still running — as the reactor cleared, for example, we could decontaminate that while the reaction mixture was still passing through the separation stages of the process.’

This had to be done manually, however, and still caused delays to production.

The PICME project began with a Masterclass which assessed production at AH Marks and determined that product changeover and decontamination were the most significant areas that could be improved.

Data from previous decontaminations were studied by both AH Marks and PICME staff, picking out where the best performances had occurred. This allowed the teams to look at the situations which had deviated from these best performances, and find out whether there were common features, such as unneccesary extra steps, that could be eliminated from the decontamination routine.

Most of the necessary changes that were made concerned operational changes, such as a new planning matrix to raise the awareness of when product changeovers were needed. There were also some minor changes to the process parameters, including changes to column feed rates, water flush, column drainage and mixer settlers.

But the main changes were to the plant DCS and other control systems, and to the data collection systems on the plant.

Previous systems had suffered from incompleteness and/or inaccuracy, and a new system was needed to provide accurate information about where losses were occurring, Shaw says.

The project was a lengthy undertaking, lasting for around 15 months.

‘Decontaminations don’t happen every day, and it was necessary to try to view the results of the analysis to show benefits were being gained,’ Shaw explains.

‘It was clear from the first product chanegover that times had been reduced. The increased knowledge of this part of the process has allowed improved production planning and 90% of changeovers now happen inside the original target time, through correct product sequencing.’

The time saving is considerable. The new system allows the company to finish making one product, carry out the necessary decontamination and start making a second product in a smooth, continuous process — while one run is finishing, decontamination begins, and once the first vessel is clean, it can be charged and reaction started while the rest of the plant is still under decontamination.

The decontamination process now takes up 8.9% of the available running time on the plant, compared with 28% before the PICME team came in.

In financial terms, AH Marks has calculated that the process improvements have contributed a ‘seven-figure saving’ to the company’s bottom line.

The company now intends to put its experience with PICME to use elsewhere in the operation.

‘The management team wanted to capture as much of the learning process as possible, so similar programmes could be rolled out in other areas of the site,’ says organisational development and training manager, Owen Dyson.

‘Our team of operators, craftsmen and middle managers were encouraged by us, and by PICME, to work together, and quickly developed a will to make the project a success. The end result was befitting of the hard work all the team put into the project.’

The AH Marks team will present details of the project at PICME’s forthcoming conference in Telford, to be held 26-27 September, which will also include presentations from Innovia Films, Geberit Terrain, Tetley, McFarlan Smith, and from PICME itself.