FLOW CHEMISTRY
raw materials . This seemed like an easy win technologically , but then a few months later the project was cancelled . The price of two of the major chemicals required skyrocketed , completely offsetting the economics of the process .
So , we all know the benefits of flow chemistry from a technical point of view . Safer processes in smaller equipment , increased productivity , better yield and selectivity , smaller footprint , less use of natural resources and energy , and lower CO 2 emissions . While these benefits are widely acknowledged , it is all still just one side of the coin .
Why change ?
No company is going to invest in continuous manufacturing if it does not lead to an economically more beneficial plant . It is important to realise that the requirements of doing a successful flow project in the lab may have quite different drivers for making it into a full-scale production plant .
It all begins with an incentive to invest . If there is a working plant , then why change a successful strategy ? Existing plants often drive investments , with grassroots projects being less common , though they do happen from time to time .
Safety regulations are becoming more stringent , particularly with the promised reshoring of production to Western countries . Globally operating companies now scrutinise their entire supply chains for safety and sustainability . This trend is driven by both client expectations and regulatory pressures .
Companies must ensure that their processes meet rightfully stringent safety standards , which often necessitates adopting continuous manufacturing technologies that offer inherently safer operation due to their smaller volumes and better controlled conditions .
Another critical issue in carrying a lab process to plant-scale production is the fact that optimal lab conditions may not always be
Typical process development set-up for flow chemistry trials in the lab
economically viable for plant-scale operations . R & D teams , process design engineers , project managers and plant managers alike must weigh the benefits of achieving optimal lab conditions against the costs and practicality of implementing them in a plant setting . For instance , a lab might find that a certain reaction yields the best results at a specific temperature , but maintaining this temperature at full production scale might require significant investment in cooling systems .
An example of this from my experience involved a highly exothermic multiphase ( gas-liquid ) reaction . Flow chemistry experiments in the lab determined that the best selectivity and yield were achieved at 10 ° C . However , the plant ' s existing infrastructure only supported – 20 ° C coolant methanol or 5 ° C chilled water for cooling .
The decision then was whether to invest in new temperature control systems or accept a minor loss in selectivity and energy-efficiency . This scenario highlights the need for flexibility when integrating new continuous processes in existing infrastructure in plants . The optimal conditions for a chemical reaction determined in the lab may require specialised equipment or environmental controls that are not feasible in a production setting .
Can it be scaled ?
Finally , scalability is a critical factor . Selecting a technology in the lab that gives fantastic results but cannot be scaled up to the required production scale is a no-go . You will get stuck at the end of the road ; a lot of investments in lab and pilot testing will have been made but there is suddenly no way you can move forward with this technology towards plant scale .
Two interesting examples of this are related to a nearly identical physicochemical emulsification Flowid performed for two different clients : a food company in 2016 and a pharmaceutical company in 2019 . In both cases we got excellent control of temperature and droplet size distribution . Again , a success from a technical point of view for both clients on ( almost ) the same process .
The lower margins and the higher volume flows required at plant scale for the food company , however , made it technically questionable at best and certainly uneconomical to scale to production . Meanwhile , the higher margins in pharma , together with the smaller required volumes , allowed for a single emulsification unit to meet plant production demands with a good ROI .
These examples and others have taught this freshly graduated process engineer from 2014 a valuable lesson . A success story does not only depend on the technical or engineering benefits , even if they are proven and guaranteed . To quote James Carville while working on the strategy of the US presidential election campaign of Bill Clinton in 1992 : “ It ’ s the economy , stupid !” ●
Dr Kevin van Eeten
DIRECTOR DEVELOPMENT & FLOW SOLUTIONS
FLOWID k + 31 6 4585 5431 J kevin . vaneeten @ flowid . nl j www . flowid . nl
44 SPECIALITY CHEMICALS MAGAZINE ESTABLISHED 1981