Energy management in polymer filler processing remains a major challenge in developing economies, where grid reliability is poor and fuel prices are unstable. This study presents the design, modelling, and experimental evaluation of a hybrid propane/electric thermoplastic powder production machine. Three systems were assessed: electric, propane-fired, and hybrid dual-mode. A structured decision matrix using six weighted criteria: heating efficiency, time to reach melting temperature, energy availability, energy conservation, machine simplicity, and production cost was applied. The hybrid system achieved the highest score (185), outperforming the propane (168) and electric (145) systems. The developed 3 kW hybrid machine features a cylindrical melting furnace (300 mm diameter, 320 mm length), a 2000 W dual-mode heating coil, a 500 mm barrel, and an auger screw operating at 45 rpm driven by a 2.5 kW gear motor. It also includes a recirculating cooling unit and a hammer mill pulverizer. Thermal modelling was based on the three-dimensional heat conduction equation in cylindrical coordinates, alongside a total energy balance incorporating conduction, convection, and radiation. Performance tests showed melting, cooling, and milling efficiencies of 34.3%, 23.8%, and 89%, respectively, with an overall efficiency of 50%. The machine processes 61.1 kg/h, producing polymer powder with particle sizes of 40–60 µm, a density of 0.8324 g/cm³, a moisture content of 0.37%, and a volatile matter content of 82.2%. Finite element analysis identified heat concentration zones at the auger tip–barrel interface, informing improved thermal management. Overall, the hybrid system offers superior flexibility, reliability, and suitability for decentralized production in resource-constrained environments.
Ojariafe et al. (Tue,) studied this question.