W.S.G. Isaac Newton

My internship was done at the Host Biogass department. Before the internship, a diverse assignment was set up together with the external supervisor. The goal of the internship was the optimisation of heat recovery from digestate.

A large part of the operational costs of a digestion installation is due to the electricity that is required for keeping the digesters at the desired operating temperature. Within the current global situation, in which energy prices are increasing, This part of the operational cost gets increasingly larger. For this reason, HoSt wants to use as little external energy as possible. This can be done by re-using the heat that’s already available within the installation instead of adding external heat and is currently being wasted, an example of this being the heat from the outgoing digestate and therefore the energy that was still within this digestate leaving the digester. The challenge was to recover this heat as cheaply as possible to heat up the new manure that was entering the digesters. A relatively affordable way of doing this is by implementing a plate heat exchanger. An example of such a unit was being implemented in Boornbergum during my internship, this allowed me to do experimental runs on this newly implemented heat exchanger. Using the data gathered within the operations and the elaborate research I did on fouling behaviour within the heat exchanger (which included making a model on when to switch flows to keep fouling as low as possible), I could improve a previously made model for estimating running conditions and required configurations and dimensions for plate heat exchangers. The goal was to validate and optimize the model in such a way that its estimations were such close to the real-life situation that it could be used as a good estimate for running conditions and required design parameters for future plate heat exchangers in similar projects. Furthermore, I looked into a different heat exchanger that uses a ring within the tank to exchange the heat. Finally, I made a model in which the different options can be compared. The goal of this model was to find the most effective and economically attractive heat exchanging option for different situations and different required return on investment times.

I can honestly say I enjoyed my time at the company and there were always kind and helpful people around to help me throughout the internships. Furthermore, a proper mix of work, education and fun was provided, with adequate educational trips to some of the plants operated by the host, as well as social activities including a BBQ and a murder mystery including a 3-course dinner.