The missing link in chemical process control
Chemical engineering defines a number of ‘unit’ processes, those that have a single specific function, leading to the production of chemicals and including such functions as separation, purification and mixing. Reactors perform perhaps the most critical unit process, the reaction process, in the transformation chain leading from chemical ‘feedstock’ to desired final products. A number of commercial simulation and optimisation packages exist for unit operations, generally exclusive of chemical reactors due to the variety and complexity of parameters. However, in order to ‘scale up’ a chemical reaction from laboratory to industry, precise understanding of the parameters governing reaction kinetics is required. Kinetics are affected by a multitude of factors including temperature, pressure, catalytic binding sites of molecules and stoichiometry, or the ratio with which molecules combine. The need for numerous experiments conducted by highly qualified theoretical chemists in order to define reaction kinetics often leads to unacceptably high costs. Automation leading to advanced reaction control was the goal of the Aitekin project. Plug flow reactor (PFR) models are commonly used to describe chemical reactions in continuous flow systems. The fluid is modelled as numerous thin ‘plugs’, as if a salami is sliced and then put back together. The PFR enables prediction of chemical reactor behaviour, leading to optimisation of reactor design. Aitekin project scientists delivered a PFR with hardware to conduct temperature scanning (TS) kinetic experiments, where TS is used to measure reaction rates, associated temperatures and levels of chemical conversion quickly and accurately. TS was integrated with artificial intelligence (AI)-based software to enable identification of kinetic mechanisms and design of an industrial-scale reactor and control system with limited human involvement. The TS-AI software simulating the chemical reaction unit of process control was then combined with two different commonly available simulators of the other process steps. Aitekin thus delivered a fully operational beta version simulation package with all process units including the chemical reaction process unit not typically available in commercial software. The ability to automatically identify kinetic reaction mechanisms should save invaluable time and money, providing a major boost to the European chemical industry.