I am working as a post-doc researcher at the University of Messina (Italy) in residual biomass gasification and energy integration with the local agri-industry. A peculiar residue is the one from the citrus juice factories, which presents some challenging features.

I was already aware of the BRISK project’s opportunity since its first edition, which allowed me to perform experimental campaigns during my PhD, start new international collaborations, and meet interesting people working on biomass conversion.

Hence, I was looking forward to the right moment to apply for the BRISK 2. I contacted the host institution, the TNO research centre in Netherland, to test dried citrus peel in the Milena reactor, an indirect gasifier with a design providing several advantages compared to direct gasification.

Then the COVID-19 spread massively in Europe, and we had to postpone the experiments. After few months, when several Universities in Italy stopped travels abroad without a clear perspective (as I am writing, several restrictions are still in place), I realized that the best way to get something was to follow the experimental activities from home.

Thanks to researchers’ availability at TNO and the BRISK2 Project Coordinator, it was possible to finalize the experimental campaign following the activities step by step from remote. The experiments consisted of testing the dried citrus peel in the Milena gasifier at different temperatures (750-850°C) and steam flow rates (1-4 kg/h), at a constant biomass flow rate of 5.5 kg/h. A micro-GC analysed the producer gas stream, and the tar was collected by the Solid Phase Absorption (SPA) method for the quantification of aromatic hydrocarbons and phenols.

Also, the flue gas from the combustion reactor was analyzed. Because of the time needed for the system stabilization, it was possible to investigate four different steam flow rates per day while the temperature was fixed and changed the following day. Despite the high ash content, the experiments were carried out without agglomerations or sintering.

The highest H2 concentration was observed at 3 kg/h of steam and 850°C, reaching about 40%vol/ vol (dry syngas concentration). The Cold Gas Efficiency reached about 88% at 850°C and 2 kg/h of steam flow rate.

The results will be used to describe the thermochemical behaviour of citrus peel in indirect gasifier. The energy and mass balance will be assessed, as well as the energy performance. Furthermore, the experiments’ results will be used in an additional research study to simulate the indirect gasification of citrus peel and the process integration with downstream processes for hydrogen, biofuels, heat, and power production.