InnoVenton and The Downstream Chemicals Technology Station
Product and process development R&D require a considerable and multi-disciplinary effort. This is addressed through:
These efforts are currently addressed through three research focus areas, namely catalysis research, micro-structured reactor tecnologies, and flow reactor technolgies.
Study of catalytic autoxidation and oxygen-transfer oxidation systems with the view to improve the selectivity and efficiency of such processes. The emphasis of these studies and in particular oxygen-transfer processes, are on the production of high-value, small volume chemicals.
Micro-structured reactor devices have certain very specific properties that distinguish them clearly from traditional processing equipment. The most important of these are:
On a typical micro-structured reactor surface, this ratio is about 200cm2 cm-3, compared with 1cm2 cm-3 for a 100ml glass flask and 0.06cm2 cm-3 for a 1m3 batch reactor. This high heat exchanging efficiency permits highly exothermic reactions to be performed under isothermal conditions. The development of hot spots and the accumulation of reaction heat within the reactor are suppressed so that undesirable side reactions and fragmentation are hindered.
Mixing in micro reactors can occur through diffusion between laminar flow layers, which are very rapid in micro channels. In certain reactor types, or mixing elements, effective turbulent flow may be achieved to provide very rapid mixing throughout the reactor. This is particularly advantageous where highly efficient mixing of multi-phase reactions is required.
Process parameters such as pressure, temperature, residence time, and flow rate are more easily controlled in reactions that take place in small volumes. The hazard potential of strongly exothermic or explosive reactions can also be drastically reduced. Higher safety can also be achieved with toxic substances or higher operating pressures. All of these advantages can be used most favorably in kinetically controlled reactions.
From the above it becomes clear that micro-structured devices offer significant opportunity in terms of process intensification by a process that comprise matching various dynamic features of devices with the physico-chemical requirements of a particular reaction system, including:
One of the foremost challenges currently facing the Chemical Industry is the need for alternative production technologies that are economic, safe, environmentally friendly, and that meet international regulatory developments.
For downstream chemical processing where production volumes are relatively small and where campaign-style manufacturing is often applied, there is an additional requirement, namely production facilities which need to be made as versatile as possible in an effort to reduce capital expenditures. While typical batch production facilities are well suited to campaign-style production efforts, they are not always the most technologically efficient way of manufacturing. Their most severe drawbacks are the rate and efficiency of mixing (especially for fast reactions) and their poor heat transfer characteristics.
Processes should be efficient in both energy and raw materials consumption and produce minimal waste. To meet these requirements implies a high degree of control over such aspects as mixing efficiency (mass transfer), and heat transfer during synthetic reactions. Such control becomes only feasible when reactions are intensified.
While intensification in itself may be achievable for any given reaction system, the true challenge lies in multi-step procedures where conditions may differ from step to step. In normal CSTR (batch) reactors, conditions cannot be altered rapidly and independently without affecting previous or following steps short of using a separate CSTR for each step.
In addition to reaction control, one of the biggest obstacles to rapid and efficient transfer of laboratory results to commercial levels is the requirements normally associated with scale-up. While chemical engineers are well trained to handle issues relating to scale-up in continuous processes, batch chemical processing scale-up issues are hardly considered.
In a truly ideal world, the goal would be to eliminate the need of scale-up during chemical process development. While this may sound idealistic, such goals have been achieved previously, electrochemical process scale-up probably providing the best-known examples.
Today, alternatives to scale-up include such approaches as numbering-up (as for example in electrochemical processing), scale-out, and "lab-scale equals production scale".
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