The majority of biomass CHP systems commercially available are based on producing steam in combination with a steam turbine or producing thermal oil for an ORC (Organic Rankine Cycle) unit.
Biomass CHP systems are typically larger than the systems outlined in the BRICKER project from CARTIF. These specified plants are not in manufacturer’s portfolio because the thermal requirements (high thermal oil or steam temperature) for such a power range (building level) are innovative.
Aspects of innovation:
- Nowadays solar and/or biomass heating systems are used in buildings but the simultaneous use of them in an optimal CHP system is new.
- Biomass boiler will be able to work with high efficiency and low emissions at partial loads, by means of an optimized design and the automatic control system.
- Optimization of the series or parallel operation mode of the biomass boiler and the solar collector with a control system based on predictive radiation forecasts.
- Temperature control in the grate furnace to avoid ash fusibility of the biomass.
BRICKER’s objective in this field is to design and develop the specific requirements for biomass plants to work within a hybrid system. This will then be used for cogeneration prototypes to be integrated in public buildings.
Emphasis will be put on the following technological advances:
- Dimensioning of the boiler components and storage buffers to minimize inertia and optimize start-up.
- Design of the feed and combustion control system to work as a hybrid system with the existing boilers in Belgium and the solar filed (and existing heating systems) in Spain.
- Optimization of the biomass supply and ashes management strategies.
- Exploration of the measures to reduce the boiler’s emissions (VOCs and particles) to improve the exhaust air quality.
- Evaluation of the economic impact of biomass consumption at a life cycle basis.
- Study of the biomass local markets (availability and prices).
The biomass boiler plant required for this application needs to accomplish various targets in order to be fully adapted to ORC units operation: fast load response, operate with a wide range of biomass fuels and in hybridization with solar technology taking into account cost-effective, high efficiency and low emissions at partial loads issues.