The Optimization of Steam Generation in a Biomass-Fired Micro-Cogeneration Prototype Operating on a Modified Rankine Cycle

Abstract

According to the United Nations, one of the sustainable development goals is to ensure access to affordable, reliable, sustainable, and modern energy for all. Among other options, these goals can be achieved by developing and introducing micro-scale combined heat and power systems powered by renewable energy sources, including solar and biomass energy. Considering renewable energy-powered cogeneration technologies, the most promising are steam/vapor turbines, Stirling engines, and thermoelectric generators. This paper focuses on the selected operational aspects and retrofitting optimization of the prototypical micro-cogeneration system powered by a biomass-fired batch boiler and operating according to the modified Rankine cycle. The existing installation was tested, and the amount of energy transferred from the oil to the condensate and steam and the efficiency of the evaporator and the superheater were determined. A retrofitting optimization aimed at maximizing the piston engine’s power output was conducted based on the results. In particular, it was shown that the system’s power output might be as high as 9 kWe. Moreover, the analyzed system featured a high energy utilization factor of 97.9% at optimal operating conditions. In general, it was shown that the micro-scale steam Rankine system may successfully serve as an alternative technology for micro- and distributed cogeneration systems. As a technology supplied with renewable biomass energy and operating on a cheap and environmentally friendly working medium (water), it fits very well into the idea of sustainable energy system development.

Techno-Economic and Environmental Impact Analysis of a 50 MW Solar-Powered Rankine Cycle System

“…Ehtiwesh et al [20] developed a dynamic model of a direct steam generation (DSG) solar power system with a steam accumulator using Simulink and MATLAB to meet a Libyan hospital's fluctuating electricity needs, featuring advanced controls for safe operation and efficiency. Sornek et al [21] evaluated a micro-cogeneration system powered by biomass, utilizing a modified Rankine cycle for potential retrofitting optimizations, achieving up to 9 kW output and a 97.9% energy utilization factor, supporting sustainable energy goals through renewable sources. Huang and Marefati [22] assessed a solar-enhanced municipal solid waste incineration plant, finding it produced 16.1% more energy and had higher efficiencies, with an 8.93% lower levelized cost of electricity despite higher costs.…”