The research site :metabolon on the former central landfill Leppe near Lindlar deals with the cascaded use of raw and residual materials as well as thermal, chemical and biological conversion processes. Research focuses on processes for the material and energetic use of secondary raw materials. Within the framework of the :metabolon IIb funding project, two new semi-industrial-scale research facilities for biomass gasification and pyrolysis are being constructed, which TEER is supporting scientifically as a cooperation partner and is supervising two doctoral projects within this framework.
Gasification of biomass
Thermochemical biomass gasification is a conversion process in which a high calorific value gas is produced from biogenic fuels. This product gas can be used in gas engines or fuel cells for the combined generation of electricity and heat. As a synthesis gas, it forms a basic material for the production of long-chain hydrocarbon compounds such as methanol or biofuels. Low-emission and automatically operated wood gasification plants are state of the art, but they have high demands on the fuel, which is why high-quality pellets or wood chips from trunk wood are generally used.
The rising prices for high-quality wood fuels represent an inhibiting factor for the economic efficiency of biomass gasification. Moreover, the thermal utilization path of classical trunk wood competes with the material utilization. For this reason, the subproject biomass gasification aims to develop regionally available residual biomass for the gasification process (e.g. landscape conservation wood, residual wood and waste wood). With this approach, primary energy raw materials are conserved and secondary raw materials, which cannot be used for high-quality materials, are used energetically in the sense of the European waste hierarchy.
In comparison to debarked trunk wood, the problematic process properties of biogenic residues are increased ash contents and reduced ash softening temperatures, which can lead to the formation of ash agglomerates at local temperature peaks in the reactor. This slagging results in reduced efficiency and operational disturbances up to plant standstill. With the aim of a stable and low-maintenance operation, the extent to which adaptations of the plant technology and/or an upstream conditioning of the fuel can reduce the ash agglomeration is investigated.
A further objective of the research project is a low-emission operation of the process with a view to relevant guidelines under the given framework conditions. For this purpose, an accompanying emission measurement and evaluation is planned. With regard to solid process residues, it is planned to reduce their pollutant load (e.g. PAH, BTX) by means of an adapted process design, so that harmless, economical ways of utilisation can be demonstrated, e.g. as an energy source in the form of fuel dust or fuel briquettes.
In previous projects at TEER extensive competences in the field of assessment and evaluation of the gasification process have been developed, including the transfer of a prototype for the gasification of residual wood pellets to series readiness. These competences are now to be taken up and systematically expanded in the :metabolonIIb project.
Pyrolysis of selected residual and waste materials
The :metabolon subproject - pyrolysis- investigates the concept of thermal processing of secondary raw materials from waste for material utilization as well as the treatment of biogenic residues as carbon carriers for material and energetic utilization.
The aim of this innovative research approach, in the sense of the European waste hierarchy, is the substitution of primary raw materials for sustainable resource management. The thermochemical treatment by pyrolysis has been chosen as the procedural approach, which will be extensively evaluated and balanced within the framework of the research project.
Pyrolysis has the potential for the thermal pretreatment of waste materials, for which effective mechanical treatment has often proved difficult in the past. For example, metal-organic compounds can be treated in a targeted manner and then recycled. The innovation of the Pyrolysis subproject lies, among other things, in the first scientific application of this process for the recycling of acutely relevant waste streams, such as composite thermal insulation systems, or materials made of carbon fibre reinforced plastics (CFRP).
Furthermore, the production of high-quality vegetable coal by pyrolytic treatment from regionally occurring biogenic residues is investigated. This creates the possibility for the state of North Rhine-Westphalia in particular, as an industrial heartland of Europe, to reduce its dependence on fossil fuels.
The possibility of deliberately varying the process parameters of pyrolysis opens up specific treatment methods for waste and biogenic residues. Here not only the singular material transformation is scientifically accompanied, but also the entire process chains with the goal of the utilization and use of intermediate and final products are considered. In this way, the :metabolon IIb project offers the opportunity to bring innovative technologies to technical maturity and thus to identify ways for the sustainable utilization of anthropogenic and biogenic residues at an early stage.
The project :metabolon IIb ist sponsored by the European Regional Development Fund.
More information can be found on the project's website (only in German).