Steve Leech outlines some key areas that can have a big impact on releasing a process plant’s productivity potential
Recent headlines have concerned the taxing issue of national productivity. The government wants, in the words of the Chancellor George Osborne, to “crack the UK’s productivity puzzle” as a key factor for future prosperity, and as a response to the recent challenging economic conditions.
Although a slowly improving fiscal outlook and higher levels of employment are welcome steps in the right direction, nonetheless figures show that UK plc productivity has languished since the dark days of the financial crisis. According to the Office for National Statistics (ONS), the UK lags behind every G7 advanced economy bar one. Indeed, estimates indicate that output per hour and output per worker is 20% lower in the UK than that achieved by the USA, Germany, France, Italy and Canada.
The Government’s productivity plan, published in 2015, demonstrates a desire to focus on technology investment, skills development, infrastructure spending and driving innovation to support general productivity improvements and fuel economic growth. But what does this mean for those charged with optimising process plants so that increases in productivity can help ensure a brighter future?
There are many areas that can support productivity objectives and true optimisation across a process plant. The following are indicative - though not exhaustive - of some of the key aspects to consider on the road to improved process plant productivity performance.
Transparent process operation
The distributed control system (DCS) is the ‘window to the process’ - the human-machine interface. Any action in the process plant can be operated and controlled via the DCS. Clearly structured user interfaces offer an excellent overview of the entire production process and provide safe and comfortable process operation. Considering the overall supply chain of a production plant from raw material supply via production to product delivery, the production itself is the central step, and the DCS is the central data source for information on production. The integration of the DCS into the IT processes of supply chain management is the foundation of cost transparency in production, such that the financial effect of specific operation sequences can be accounted or predicted.
Advanced process control (APC)
APC methods can be an essential tool to help improve the productivity of a process plant with regards to product quality, operability and availability, agility, safety and environmental issues. APC solutions can be realised much more cost effectively due to a DCS embedded implementation with standard function blocks and pre-defined wizards and templates for implementing basic APC principles.
Batch scheduling
The transformation of production orders to a detailed schedule of batches on certain plant units at given starting times contains optimisation potential in the sense of efficient plant operation. Several optimisation targets have to be pursued at the same time while considering limited production resources. These can include: compliance with delivery dates and specifications of product quality; maximising capacity throughput; minimising cleaning efforts when different products are run in the same tank reactor and avoiding peak loads in energy consumption. Again, process optimisation tools such as Simatic Batch can help with batch planning and automatic execution of planned batches.
Virtual commissioning and simulation tools
If the process sector is to match the automotive and aerospace examples with regards to productivity levels, then the use of agile, flexible and proven automation technology solutions such as virtual commissioning and simulation tools to aid engineering projects, automation system design and even new plant delivery, holds the key.
The requirement for ever shorter commissioning and start-up timescales for new production lines, plant migrations or new plant facilities, is a reality for many. This is where the added value advantages of virtual commissioning through a simulation framework can offer tangible and proven time, resource and cost benefits.
Virtual commissioning enables real-time simulation of extensive engineering projects to design, engineer and test automation projects without the risks of working within a ‘live’ environment. Consequently, automation system design testing and the delivery of higher quality code can, for example, shorten overall commissioning times, reduce project risk, eliminate human error, support operator training goals and, ultimately, allow automation projects to move from a test to live environment seamlessly and speedily.
Safety and industrial security
Increasingly safety and industrial security are being seen as two major potential factors that impact on productivity. The use of safety instrumented systems (SIS) that comply with the international standard IEC 61511 has been the process industry norm for many years. There are distinct economic benefits that can be achieved through taking a ‘safety integrated’ approach to SIS. The goal of safety engineering is to avoid accidents and consequential damages after occurrence of errors to achieve maximum safety for humans, process and the environment. Operation and construction of process plants with risk potential have to comply with the international standard IEC 615 11 for functional safety of safety instrumented systems. The connection between SIS and industrial security is a focus for the process industry. The threat of a cyber security attack in relation to SIS can have long-term damaging effects on a business in terms of impact to human life, ability to produce and brand image. Increasingly, the need to consider and develop an industrial security strategy is becoming day-to-day life for the process industry, a defence-in-depth based approach provides the best opportunity to overcome this issue and ensure that safe production can carry on.
Lifecycle services
The costs arising in the operational phase of a process plant constitute a significant share of the overall life cycle cost over the typical 15-20 year asset life of a plant control system. The baseline for profitable life cycle costs is high plant availability, achieved by a robust DCS with solid application software based on standards and by preventative plant maintenance. Service costs for engineering support, maintenance and upgrades play an important role as well. Consequently, plant management should be aware that the main requirements for a comprehensive service package include: investment protection through service products; system availability by ensuring serviceability; serviceability using suitable migration concepts and clear obsolescence management linked to the market withdrawal of technical components or software versions.
Obsolescence has typically proved a cyclic problem that has culminated in the large amount of legacy control systems we see on UK plant infrastructure. The conclusion that plant owners/operators quite rightly draw is that a large part of the decision-making process to migrate to a modern process control system is its ability to be modernised and innovated without reproducing the same legacy issues that have gone before. A modern DCS platform such as Simatic PCS 7 comes with those lifecycle guarantees built in, so process manufacturers no longer need to feel that this is a cross they have to bear.
Steve Leech is business manager Process Control Systems, Siemens UK & Ireland.