Processes and Safety
At its very heart, chemical engineering is process engineering, which developed through a demand to improve capacity, efficiency, and therefore profitability of industrial scale plants. For over 100 years, expertise has been applied to successfully scale up innovations, including the production of a vast array of synthetic materials, the refining of crude oil, the bulk manufacture of pharmaceuticals and plastics, and the production of some of the most ubiquitous materials in our daily lives.
From traditional large tanks stirred by paddles in batch processes, through to continuous flow processes made possible by the development of reactor kinetics and an understanding of heat and mass transfer, process engineering has driven manufacturing by transforming low value raw materials into high value commodities.
Following World War 2 and the rapid growth in the petroleum and petrochemical industries in Europe, representatives from large American engineering design and construction contractors descended on London, keen to access British engineering and design capability. IChemE took advantage of this momentum and provided active agendas for IChemE technical meetings and annual forums with industry speakers to discuss research, technology and significantly, safety.
Influencing the design, optimisation, monitoring and operation of manufacturing processes of all types, process engineering has evolved with the digital revolution, to transition from manual operations to automatic control through the use of slow early computers, to micro-computers and wireless sensors. As Information Technology (IT) has advanced, so too have the capabilities for process safety and product quality control.
Technical process safety is distinct from occupational health and safety and it is the top priority for chemical engineers. In the early 1980s advances in technology made human interactions more complex and there was an increased understanding of how accidents happen, which led to the recognition that human factors were relevant and critical to safe operation.
Moving on from trial and error
In 100 years, the management of process safety has evolved from trial and error to a more hazard conscious, risk aware and ‘right the first-time’ approach. Modern practice is proactive and uses data, modelling, and research/knowledge to embrace an inherently safer approach of avoiding, minimising and isolating hazards.
Risk analysis and mitigation tools that are now routine, e.g., HAZOP (Hazard and Operability) studies, were developed by pioneers like Trevor Kletz from Imperial Chemical Industries (ICI) in the 1960s and 70s. The concept of inherent safety was introduced in his paper What you don't have, can't leak, after the Flixborough accident in 1974.
His advice to build simpler and fault tolerant plants recognised that human operators were often one of the causes of accidents, although usually not the root cause. This legacy has meant that robust safety management systems have become standard practice.
Yet major accidents and loss of life have continued to occur, albeit with lower frequency but with severe consequences nevertheless (notable examples include Seveso 1976, Bhopal 1984, Piper Alpha 1988, Buncefield 2005 and Deepwater Horizon 2010). Each accident has led to more action and commitment to improve safety. However, we cannot and must not relax as accidents continue to happen.
Important advances include goal-setting regulation, pioneered by the UK’s Health & Safety at Work Act (HSWA) of 1975. In 1982, in response to the Seveso disaster in Northern Italy, where 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) leaked into the surrounding environment, the Seveso Directive was issued as a European Union directive, with the aim of improving the safety of sites containing large quantities of dangerous substances.
Process and safety in a new era of chemical engineering
A major contribution of chemical engineering has been the development of ‘hazard study’ techniques to proactively find problems in advance, thus allowing risks to be managed through structured process safety studies, thus reducing incidents, loss of life, and minimising impact on air, waterways and soils.
As technologies change, so too will process engineering risk management practices. But the interdisciplinary systems approach, which recognises that many things or phenomena are formed of or the result of cohesive groups of interrelated, interdependent parts, will remain a key skill for chemical and other engineers.
Advances in health care and clean energy will rely on the know-how of future chemical engineers, who will need to have a good understanding of biology, biotechnology, artificial intelligence and new processes for new feedstocks.
The development of practical electrical power storage technology is another opportunity for chemical engineers, where possible systems include manufacture and storage of intermediate chemicals, such as hydrogen, green hydrocarbons and ammonia as well as the scale up of new battery technology. While the theoretical basis is understood, chemical engineers need to safely develop the processes to scale.
As our tolerance of risk and injury is much less than it once was, safety will become more important in the future, and public pressure, now amplified through social media, will push chemical engineers to ‘design out’ the possibility of low frequency but high consequence events.
In the modern workplace, ill health is an increasing workplace safety concern, and the duty of care is for both physical and mental health.
The world is facing its biggest challenge due to the impacts of increasing population and economies with consequences such as climate change, species extinctions and poverty in developing nations. To counter this, chemical engineering is well placed to deliver solutions, skills, and creativity to an array of technologies to advance the health of the community and the planet. It is vital that knowledge of process and safety is shared with developing countries to meet this challenge.
We all have a responsibility to address exponentially increasing human populations and economies, not just philosophers, demographers and economists.