Cement is a major and essential component of buildings construction the world over. Yet it is responsible for 7-8% of global carbon emissions (source: The Guardian (UK)).
Decarbonisation of its manufacture is a key priority for chemical engineers as they drive industrial processes to net-zero. Initially, carbon capture and storage using processes like calcium looping which uses some of the minerals used for cement to also capture CO2 inevitably produced from limestone in the process, in addition to that produced by powering it with fossil-fuel energy. This is a good example of where the challenge is turning a good concept into an economically viable reality. Longer term, new decarbonised manufacturing processes and innovative low-carbon cement-like materials must be developed and chemical engineers have the skill set to do this.
Steel is one of the biggest examples of chemical engineering at work. But whilst most of the world demand is still from blast furnaces that looks set to change. The new aim is to produce steel with ‘net-zero’ carbon emissions, replacing coal with hydrogen and extension of electric-arc type processes to electrify the production process.
The efficient extraction and recycling of the metals required for batteries (such as lithium and cobalt) is the next challenge as electric vehicles take to the roads. Sustainable management of these mineral resources, low-energy extraction and ensuring ethical mining and local labour practices are all key issues to be addressed, to ensure that the renewables-energy storage era preserves the earth’s natural resources and environment in a way that the hydrocarbon era has not.
Plastics have revolutionised the way we live since the first Bakelite less than a century ago. Today, plastics are everywhere: in food packaging, fibres, textiles, our homes, and our cars. They are cheap to make, clean and versatile.
But the environmental impact of irresponsible disposal and inadequate recycling is there for all to see. One next step in the journey being explored is the development of bio-degradable plastics which break down naturally. All-new bioplastics which are made from starch or cellulose could be the long-term substitute for today’s crude oil-based plastics. However, the development of biodegradable plastics, whilst useful, still represents a modest development within the waste hierarchy; this still assumes a future system that allows to produce single use materials. Biodegradable plastics would only be a material improvement if they can be used to fertilise the bio-matter from where they were made. So chemical engineers, and society, need to increasingly embrace materials and approaches that encourage effective multiple re-use or maximum recycling.
The huge growth of the chemicals and materials industry in the middle part of the last century was largely based on the centralised production of high-volume bulk chemicals and related materials – methanol, benzene, polyethylene, polyvinyl chloride etc. Chemical engineers created the petrochemical industry that produced these materials from oil and gas based initially on conventional batch, stirred tank systems and then increasingly on continuous and more innovative processes. The 21st Century is likely to be the era of smart and specialist materials, accompanied by more modular and higher throughput processes. Energy materials will be in high demand, for devices involved in energy capture, conversion, and storage. Novel medical and electronic materials will also be needed, and chemical engineers will be at the heart of their development and the processes to produce them. Materials will become increasingly ‘smart,’ being multifunctional and changing their properties in response to different stimuli, moving controlled release to new levels of specific targeting capability. Thermo- and photo-chromism, shape memory, self-healing, phase-change attributes, advanced composites, and nanotechnology are just some of the features that will be exploited. Health, building and transport will lead demand for such materials and the creativity of chemical engineers will be required to both create and manufacture them.