Challenges in renewables scaling


Pasi Leimu
Project Manager, M.Sc.(Tech) 1990

Dealing with labile biological materials is challenging. Even more challenging is scaling them to industrial-scale production. The secret of success in scale-up is step-wise development of the processing concept in cooperation with the client and project management focusing on techno-economic feasibility – the target is maximal yield for minimal costs and time.

In bioengineering, useful metabolic products are produced from biological material in aseptic or even sterile conditions. In the wider concept of bio and circular economy, the production utilizes naturally occurring renewable materials or recyclable materials in the form of waste or side streams of another operator and develops new innovative products with suitable technologies. Engineers must have experience of multiple materials – from virgin fiber used in the forest industry to recyclable textile fiber and waste fractions of different origins. Also utilization of side streams of food production, e.g., bakeries, meat production or dairies, such as whey, is targeted while not forgetting shelf life and traceability.

Understanding fundamentals
The challenges in today’s biotech and aseptic process field are finding suitably scaled technological solutions to produce homogenous and uniform products. Usually, the trials are carried out first at the laboratory scale and then the pilot scale before the industrial- level process is reasonable and justified. The labile biological materials make the fermentation and recovery processes a harder challenge than with chemical recovery. In these cases, the engineering is only an aid to regulation of biological processes and the micro-organisms command the center of attention. A clear understanding of microbial growth kinetics is necessary if a large-scale process is to be properly managed. Growth kinetics is treated differently for conventional batch processes than for continuous processes. Although several fermentations for metabolite production work well as processes at a laboratory scale, only a few processes have proved useful for practical application due to clearly fewer operational hours to be stable in a laboratory than in an industrial set up.

Also, attention should be paid to maintaining hygienic conditions on an industrial scale over a long period of time. Variation of industrial composition of substrates has to be anticipated as well.
In the wider concept of bio and circular economy, the production utilizes naturally occurring renewable materials, waste or side streams of another operator and develops new products with innovations and technologies. In these cases, the challenge is to optimize the feed and to get constant capacity. Also scaled, reasonably priced and agile technological solutions may turn out to be difficult to find for the production stream and quality fluctuations. New occupational and chemical safety issues may also arise with circular economy cases.

From challenges to solutions

A wide network of technology providers must be utilized with whom we can create tailor-made equipment and systems, if necessary. Technical consulting and engineering offices have expertise in a process and plant design as well as clean utility systems with applicable occupational safety features. A partner who is responsible for the product recovery and supporting utility and energy
systems is useful, while a plant owner usually focuses on the fermentation (cultivation of microorganisms) itself. Experts and consultants for circular economy projects should be competent in feasibility studies, capacity calculations and dimensioning of equipment as well as risk evaluations. Clean room air condition and ventilation, clean utilities and instrumentation would also be great additions to this toolkit. Finally, proper data acquisition and analysis are essential for calculating the effects of process variables on the final outcome in every development step. Process modelling is needed in order to optimise the process faster and more cost-effectively when targeting a well-functioning, industrial- level process. Understanding fundamentals behind the process is a key factor to successful scale-up. And a link between customer R&D and equipment manufacturers is needed for hands-on knowledge. A new scale-up process can be realised only with innovative, economic-technical solutions.