Development of a Small-Scale Electricity Generation Plant Integrated on Biomass Carbonization: Thermodynamic and Thermal Operating Parameters Study

Abstract

Biomass has been known as a source of energy with a thermochemical process that produces heat and can be converted further into electricity. However, thermal energy losses are a huge problem during combustion. To overcome this problem, a system based on organic Rankine cycle (ORCs) was developed to recover and utilize them to generate electricity. The proposed ORCs include an evaporator, a turbine, a condenser, and a pump coupled with a biomass carbonizing system to create a promising technology for small-scale electricity generation. In this work, a thermodynamic modelling equation based on energy and exergy balances was briefly expressed for each subcomponent of the system. A case study with R134a as the working fluid is being investigated to validate the system’s performance. In addition to the effects of R134a on temperature at the turbine exit, the suitable operating pressures has been specially adopted from several valid journals that focused on the effects of a wide range of possible operating pressure on the working fluid characteristics, which have a significant effect on the system performance. Finally, the theoretical analysis shows that the turbine work is profitable at an inlet pressure of 5 bar and an outlet pressure of 2 bar. This system is recommended to be integrated into the thermochemical biomass process. Recommendations have been made for the future development of small-scale biomass-fuelled power generation systems. This study shows that the thermal losses of the biomass thermochemical processes can be theoretically recovered in the form of electricity by using ORC efficiently.