Subject and aim

In compliance with the requirements for combustion units according to the 4th BImSchV and TA Luft, varying leaves fractions are thermally utilized in an incineration plant (400 kW) together with conventional, woody biomass in varying ratios. In addition, their suitability for energetic use is demonstrated.

During combustion, potential environmental impacts (dust, NOx, CO, organic and inorganic substances) will be quantified and an assessment of the use in combustion plants will be made. Additionally, the influence of the collecting location (road leaves, park maintenance, etc.), the duration of the exposure and the type of storage (silage bales, briquettes etc.) on the emission behavior of the potential fuel shall be investigated in order to allow a cost-effective and energy-efficient utilization for an all-season heat supply.

After completion of the project, the municipalities will be able to produce a fuel for their own energetic utilization or for larger biomass combustion plants. The aim is to identify a narrow spatial exploitation cycle of selected leaves fractions within urban and regional boundaries. Furthermore, a cost-effective, year-round heat supply shall be made possible by the storage of leaves over a long period of time.

Measures

Fraunhofer UMSICHT
In pilot tests, optimal conditions and parameters for a densification of the fuel will be identified. Hence, the investigations are carried out as parameter studies, which provide several fuel variants for subsequent tests in the incineration plant and thus allow conclusions on the influence of the densification technology on the combustion behavior. The use of leaves for heat supply will be analyzed energetically, economically and ecologically. In addition to the biomass potential, the energy and material balancing of the conversion process, the economic efficiency and environmental effects, the results will be compared with a reference system.

Netz Ingenieurbüro GmbH
In order to implement the subproject, the heat supply potential will be analyzed by means of combustion tests in a wood firing system. In parallel, the potential for leaves as fuel, logistical supply chains and material-energetic utilization conflicts (eg composting) will be investigated in small and large cities in order to ensure a nationwide transferability.

Focus

Fraunhofer UMSICHT

• Fuel quality test
• Fuel characterization (drying behavior, ignition behavior, burnout behavior)
• Verification of the co-incineration influence on the efficiency in the combustion plant and the burnout quality

Netz Ingenieurbüro GmbH

• Development of a suitable storage method and fuel preparation
• Economical and logistical heating supply