Unlocking the potential of batch processing

Today, manufacturers face increasing pressure to find new ways to enhance production and obtain maximum return on business assets. This drive for manufacturing success holds particular challenges for the pharmaceutical industry, with its dependence on batch process plants that have to be capable of producing a variety of products at different times, and all to highly demanding quality criteria.

Governed by a complex matrix of conflicting elements, multi-product plants must have a flexible, responsive design in order to meet customer demands. Achieving this objective requires a high level of expertise and until recently companies have had to rely upon the knowledge of their design engineers alone. However, the introduction of new technology specifically designed to tackle batch plant design means that manufacturers can get the right plant design at the right cost without the headache.

Batch plant design demands balancing many conflicting factors and constraints, such as production sequence, safety stock, scale-up range and capacity of equipment. The growing trend towards global manufacturing has added another dimension to the procedure, precipitating a shift from planning one plant, to implementing a plan across many plants company-wide.

There are numerous factors to take into account. Different pieces of equipment are subject to different limitations. A reactor, for instance, has minimum and maximum stir volume constraints and a filter has minimum and maximum cake volume constraints. Expensive equipment must often be shared between several lines and it is quite likely that the same resources will be needed in different places at the same time. The efficient planning of these resources is therefore crucial.

Faced with a set of customer orders with different delivery dates and product quantities, it can be difficult to plan and prioritise production. This is further complicated as each individual product can be divided into a number of campaigns which each use a different cell. Choosing the right batch size can clearly affect the whole manufacturing chain.

Asset management and operations improvement consultancy Eutech has been one of the first companies to address the challenges posed by batch plants. The consultancy has developed a software package, Batch XL, specifically designed to tackle the issues and provide manufacturers with a method of optimising batch plant design and organisation.

Batch XL has been used in a major pharmaceutical manufacturing plant to optimise production and asset investment planning. The plant is a multi-product batch plant for manufacturing pharmaceutical actives. The software has allowed the team to explore a new design comprehensively, which would otherwise be difficult to solve. The company's process engineers have used the package to optimise the plant design by increasing occupancy and providing more efficient allocations. This has led to significant capital savings. For example, saving just two mid-size glass-lined reactors has saved £100 000; saving a single vacuum pan dryer represents a saving of £500 000.

More importantly, because the system also plans production simultaneously, the manufacturer is confident in the knowledge that the design will achieve production targets. Getting the new plant online smoothly and quickly represents a key strategic advantage in time to market.

Batch XL represents a new way of designing batch and semi-batch plants. By identifying the best resource allocation, batch size and schedule, it provides a user-friendly route to getting the most out of manufacturing assets — from plant design through to operation and planning. The user simply enters the plant equipment configuration and specifies the production slate. The software takes this information and automatically selects the most suitable combination of inputs for the given production requirements and equipment.

For example, by inputting production orders and priorities, it provides details of optimum resource allocation, batch size and production sequence, and predicts the time required to complete an order. In this way, a plant's capacity is optimised and operating costs are reduced.

Batch XL shifts the focus from modelling each product individually to dealing with the entire production slate — a significant advantage over previous systems. The far-reaching application of the package not only provides the manufacturer with a realistic solution, but also a strong indication of the design's ability to deliver, even at the earliest stage of a project. This further ensures that the costs and benefits of investment are ascertained before major expenditure is committed.

Traditionally, for each individual design concept, engineers had to specify manually which equipment would be used at each stage in each production process and then calculate the production rate. Testing out different equipment and different cells can lead designers into a vast number of possible combinations. Even for a small batch plant with just a few cells, the permutation could be 10 to the power 50. Going through all of these permutations using existing tools is clearly unrealistic in terms of time and costs.

By automatically providing the best possible solution for each plant configuration, Batch XL eliminates the time-consuming guesswork that goes into manual design. It assesses the impact of different pieces of equipment and cell configurations before the changes are made — enabling the user to examine the 'what ifs' before implementing the design. The benefits are clear — new products can be introduced smoothly into an existing plant, new/retrofit plants are put on stream earlier and, most importantly, companies acquire cost-effective world-class design concepts that are both robust and flexible.

Batch XL is as much a design optimisation tool as an offline production planning tool. It maximises plant performance by assigning production to the right set of equipment at the right time and the right batch size simultaneously.

Batch plants operate in a dynamic environment; plant resources can become unavailable due to breakdown or maintenance; production portfolio and priorities are subject to changing customer demands. As conditions change, a non-critical plant resource could become a critical one. Batch XL enables the user to identify these critical resources. This allows maintenance to be directed to the truly critical resources. It is ideal for evaluating contingency plans and examining business implications.

The package can also be used when retrofitting new equipment onto existing plant is necessary. This generally involves modifying the capabilities of an existing plant, both in terms of accommodating new products or increasing capacity. Modifying a new plant requires minimum disruption to production and accurate designs — there is no time for putting a wrong design right. Batch XL allows the user to explore the options for modifying an existing plant before implementation and so provides confidence that the design is thought through.

Optimum plant design is essential. Getting it wrong incurs extra time and costs which can be avoided by using the latest technology. The benefits of making the right manufacturing decisions are manifold. Whilst buying into the latest technological developments isn't always the right way forward, manufacturers need to give full consideration to the growing number of options available. Increased productivity, reduced capital expenditure and efficient production are all bottom-line business benefits offered by IT which competitive manufacturers simply cannot afford to pass up.

Phillip Chen is lead consultant at Eutech