FP6-SUSTDEV | BIO_MGT: Spike Renewables’ Contribution to the Thermal Recovery System
The European BIO_MGT project demonstrated the possibility of integrating biomass and natural gas into a single polygeneration system based on a microturbine. In the regenerated gas turbine cycle, compressed air does not enter a combustion chamber but is sent to a high-temperature, high-pressure heat exchanger. Here, the air absorbs thermal energy from the flue gases produced by an external source (biomass combustion), reaching the temperature necessary for expansion in the turbine. The turbine generates mechanical and electrical power along with the exhaust gases. Within this initiative, Spike Renewables was responsible for designing the thermal recovery system, essential for making the entire energy cycle efficient and for valorizing the heat available in the flue gases from the biomass boiler.
Objective of the Thermal Recovery System
The system was designed to extract approximately 190 kW from the flue gases coming from the biomass combustor, reducing their temperature from 380°C to 180°C under nominal conditions. This power is transferred to the Forteto thermal plant through a dedicated hydraulic circuit, ensuring an operating temperature between 70°C and 80°C in the service water. The system operates safely even in the absence of thermal demand, providing an autonomous dissipation solution.
Hydraulic Circuit Design
Spike Renewables developed the entire recovery circuit, defining sizing, flow rates, temperatures, and component configuration. The plant is designed to operate with a water flow rate of approximately 4.5 l/s, ensuring continuous operation both in recovery mode and when thermal power must be dissipated. Functional and connection diagrams integrate the circuit with the biomass line and the modified microturbine, as well as the direct connection to the site’s thermal plant.
Components and Integration with the Biomass Line
The design also included the integration of the air dissipator, essential for removing excess power when the system is not connected to the thermal user. Spike defined the operating logic of the circuit according to the flue gas profile and microturbine requirements, including startup, shutdown, and partial-load management. The system’s alignment with the overall energy requirements of the BIO_MGT line highlights the crucial role of thermal flow management in the plant’s overall energy balance.
Energy Efficiency and Operational Safety
The circuit designed by Spike allows the recovery of useful energy, reducing fossil fuel consumption in the thermal plant while simultaneously improving the overall efficiency of the demonstrator. The presence of the dissipator ensures operational continuity and component protection under non-standard conditions, guaranteeing robustness and reliability in daily plant operation.
A Key Element for BIO_MGT Polygeneration
Spike Renewables’ contribution made it possible to fully valorize the heat from biomass combustion, helping improve system efficiency and closing the thermal cycle of the BIO_MGT project. The solution implemented provides a concrete example of how integrated design can enhance the performance of complex distributed generation systems, making them more sustainable and replicable on an industrial scale.