TRR 129:  Oxyflame - Development of Methods and Models to Describe Solid Fuel Reactions within an Oxy-Fuel Atmosphere

• Subject Area: Thermal Engineering/Process Engineering ; Chemistry
• Term: since 2013
• Website: Homepage
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 215035359

The CRC/TRR 129 (RWTH Aachen University, Ruhr-Universität Bochum, Technische Universität Darmstadt) investigates pulverized solid biomass combustion in oxy-fuel atmosphere, i.e. a gase-ous atmosphere containing mainly CO2, H2O and O2. Replacing nitrogen by CO2 and H2O, which at high temperatures both are chemically active and strongly radiating components, results in an entirely different combustion behavior that may lead to modified chemical conversion rates, flame instabilities or even to local ignition and flame extinction phenomena. Biomass as solid fuel affects all of these processes due to its composition and inherent compound structure as well as by the associated irregular particle shapes. A multiscale approach in experiments, related modelling and simulations, is used for identification of dominating mechanisms of the governing transport processes. For example, modeling approaches of different fidelity are considered ranging from molecular dynamics simulations over approaches that partially or even fully resolve the turbulence all the way to a multiphysics and multiscale description of the system-scale with Large-Eddy Simulation (LES).The overall scientific goals of the CRC/TRR are:•Establishment of a detailed understanding of the underlying mechanisms in pulverized solid fuel combustion in a gaseous atmosphere consisting mainly of CO2, H2O and O2.•Development of validated and generalized models (combustion and transport processes) for these conditions, taking the necessary details at the individual scales into account. •Development of efficient physics-based simulation methods with known uncertainties for designing oxy-fuel combustion processes that master and optimize this technology.The CRC/TRR 129 structure is based on three project areas: Project area A (6 projects) comprises mainly the model development for reaction kinetics of solid fuel particle combustion. Project area B (7 projects) adds theoretical investigations of fluid dynamic phenomena within particle clouds, as well as investigations of the modified atmosphere’s influence on combustion. This is complemented by a cascaded set of experiments with increasing levels of complexity providing basic data for further analysis and validation. The consideration of system level phenomena including all relevant sub-processes encountered in real furnace configurations is accomplished in project area C (5 pro-jects). There, the knowledge generated by assessing oxyfuel combustion under consideration of radiation processes is combined with the models developed in areas A and B and integrated into a comprehensive modelling framework, called OxySim-129. The consolidation, optimisation and pro-fessional maintenance of this OxySim-129 framework is provided by a service project.

• DFG Programme: CRC/Transregios
• International Connection: Italy

Current projects

• A01 - Experimental investigations of pyrolysis and char conversion kinetics in a well-stirred reac-tor under atmospheric and pressurised conditions (Project Head Kneer, Reinhold )
• A02 - Experimental investigations of pyrolysis and char conversion kinetics in plug flow configu-ration with a focus on the ignition and early char burnout phase (Project Head Scherer, Viktor )
• A05 - Kinetic investigations of the effect of catalytically active minerals in biomass-derived solid fuels on pyrolysis and char conversion under oxy-fuel conditions (Project Heads Cerciello, Ph.D., Francesca ;  Muhler, Martin )
• A06 - Determination of excess-sorptive kinetics and equilibrium loadings of oxy-fuel gas compo-nents on solid fuels (Project Heads Richter, Markus ;  Span, Roland )
• A07 - Atomistic multiscale simulations of char conversion (Project Heads Hättig, Christof ;  Schmid, Rochus )
• A08 - Development of a comprehensive kinetic model for the conversion of solid fuels in oxy-fuel atmospheres (Project Head Hasse, Christian )
• B01 - Theoretical and experimental investigation on the devolatilisation and oxidation of solid-fuel particles in a counterflow burner under oxy-fuel conditions (Project Head Pitsch, Heinz )
• B02 - Development of modelling approaches for fluid-particle interactions in turbulent flow by direct particle-fluid simulations (Project Heads Meinke, Matthias ;  Schröder, Wolfgang )
• B03 - Direct Numerical Simulation and Modeling of Oxy-Fuel Combustion Processes (Project Head Pitsch, Heinz )
• B04 - Detailed experimental investigation and characterisation of oxy-fuel biomass burners via laser-optical methods (Project Heads Dreizler, Andreas ;  Kneer, Reinhold )
• B05 - Robust absorption-spectroscopic diagnostics for biomass combustion: measurement methods for gas species, gas temperatures and particle loading (Project Heads Ebert, Volker ;  Wagner, Steven )
• B07 - Investigation of ignition and combustion processes of solid fuel particles under oxy-fuel conditions (Project Heads Böhm, Benjamin ;  Schiemann, Martin )
• B08 - Sensitivity analysis and uncertainty quantification of pulverized solid fuel combustion (Project Head Sayadi, Taraneh )
• C01 - Experimental investigation of pulverised biomass combustion for validation of numerical models (Project Heads Dreizler, Andreas ;  Kneer, Reinhold ;  Maßmeyer, Anna )
• C02 - Unsteady Modeling and Simulation of Oxy-Fuel Combustion Chambers (Project Heads Hasse, Christian ;  Janicka, Johannes )
• C04 - Modeling of radiative properties of pulverised biomass particles during oxy-fuel combustion (Project Heads Kneer, Reinhold ;  Ströhle, Jochen )
• C05 - Measurement of the radiative properties of solid fuel particles in oxy-fuel atmospheres (Project Head Schiemann, Martin )
• C07 - Experimental investigation on the interaction of flame stability, radiation, burnout, and emissions in a semi-industrial-scale swirl-stabilised oxy-fuel furnace (Project Heads Dreizler, Andreas ;  Epple, Bernd )

Completed projects

• A03 - Experimental determination of reaction kinetics for the release of chlorine and sulfur spe-cies and for the conversion of these species in the gas phase (Project Head Epple, Bernd )
• B06 - Modelling of particle-turbulence-chemistry interaction for oxy-fuel processes (Project Heads Janicka, Johannes ;  Sadiki, Amsini )
• C03 - Spectral modeling of thermal radiation in oxy-fuel pulverized coal flames (Project Head Ströhle, Jochen )
• C06 - Measurement of the temperature depending spectral emissivity of ashes and deposits under oxy-fuel conditions (Project Head Scherer, Viktor )
• S - Optimisation and management of an integrated simulation platform for large-scale simulations of oxy-fuel combustion (Project Head di Mare, Francesca )
• T01 - Oxy-fuel combustion of Refuse Derived Fuels (RDF) under cement kiln conditions (Project Heads Kneer, Reinhold ;  Scherer, Viktor )

• Applicant Institution: Rheinisch-Westfälische Technische Hochschule Aachen
• Co-Applicant Institution: Ruhr-Universität Bochum; Technische Universität Darmstadt
• Spokesperson: Professor Dr.-Ing. Reinhold Kneer