GreenQUEST aims to develop green liquefied fuel gas, or gLFG, as a sustainable alternative to fossil LPG.  A key step in this journey was to move beyond laboratory-scale catalyst testing and produce enough fuel for real-world performance demonstrations.

This outcome focused on producing a large sample of gLFG using a purpose-built mini-plant.  The work built on catalyst research carried out at the University of Cape Town’s Catalysis Institute and was implemented at HYENA’s facilities.  The objective was practical and ambitious: to produce a 4-8 kg batch of gLFG that could be used for comparison with fossil LPG in two end-use applications – domestic cooking and electricity generation.

Scaling up the process presented important technical challenges. Catalyst behaviour changed when moving from laboratory powder catalyst to a commercial extrudate form, requiring further development of the catalyst preparation method.  The production process also had to address reactor temperature control, the heat released during the reaction, and blockage risks caused by heavier by-products.  These challenges are typical of the transition from laboratory chemistry to real process engineering, and they provided valuable learning for future scale-up.

Through a series of mini-plant runs, the GreenQUEST team implemented several improvements, including revised catalyst preparation, careful catalyst dilution, improved heat management, controlled dimethyl ether feed introduction, and additional heating to avoid cold spots in the system.  These changes enabled successful longer-duration operation and bulk fuel collection.

The final production runs collected a total of approximately 7.4 kg of product.  Around 1.3 kg was used for the cookstove comparison, while a further 6.1 kg, collected in three cylinders, was used for electricity generation testing in HYENA’s POWER POD.  More than 4 kg of the collected material consisted of the key C3 and C4 fuel components that make up the desired gLFG fraction.  The catalyst also demonstrated activity for more than 250 hours, and the final experiment operated for more than 300 hours, showing that earlier blockage issues could largely be overcome through improved system design and operation.

The impact of this work is significant for GreenQUEST.  It provided the real fuel required for practical demonstrations and created a stronger technical basis for future pilot-plant development.  It also showed where the next improvements are needed, especially in product separation.  Better separation, such as distillation, would allow a cleaner gLFG fraction to be recovered, improve yield, and bring the fuel composition closer to commercial LPG specifications.