Numerical simulations of pyrolysis of wet charring materials using a one-dimensional enthalpy based model

Solid phase modelling coupled to gas phase combustion of volatiles helps to investigate the flame spread over solids. The present work focuses on the solid phase. Numerical simulations of pyrolysis of wet charring materials are performed. When the solid is exposed to an external heat flux, the model is such that the moisture present first flows out, leaving behind dry solid. This solid then further heats up and finally generates a mass flow rate of combustible volatiles during the 'pyrolysis' process, i.e. the degradation of the solid. Evaporation and pyrolysis, possibly occurring at the same time, are assumed to take place in infinitely thin fronts. Pyrolysis is thus modelled as an infinitely fast, irreversible endothermic process at the 'pyrolysis temperature' (Tpyr) and as such, all kinetics are ignored. The cases considered are one-dimensional in nature, in order to focus on the principal model performance. Enthalpy is the basic model variable. The temperature distribution inside the material, along with the evaporation and pyrolysis front positions, are related to the distribution of enthalpy. A piecewise linear temperature field representation is adopted

Pyrolysis characteristics of excavated landfill waste

poster presented during 'Open Bedrijvendag'status: accepte

Waste-to-clean syngas: avoiding tar problems

Syngas from gasification of carbon-rich feedstock is used for power generation as well as for the production of synthetic fuels and commodity chemicals. Tar removal forms a major challenge in the effort to make these syngas valorisation technologies technically and commercially feasible. Tar removal methods can be divided into two categories: (1) primary methods or treatments inside the gasifier, and (2) secondary methods or hot gas cleaning after the gasifier. The most important features of the primary and secondary tar removal methods, as well as the most recent developments in this field, are reviewed and discussed in this paper. For advanced syngas applications (e.g. gas engines), primary measures are generally not sufficient. In that case, primary methods can be used as a tool to optimise the gas composition for the secondary cleaning step. Corona plasma for tar removal is discussed in more detail. This promising technology will be used in future research on the cracking of real tars obtained from refuse derived fuel (RDF) pyrolysis.status: publishe

Study of pyrolysis and upward flame spread on charring materials: part I: experimental study

In this paper, we describe the results from an experimental campaign, focused on vertical upward flame spread over a charring material. First, for validation purposes of simulation tools, we report on cone calorimeter results for square (9.8 cm x 9.8 cm), 1.65 cm thick, medium density fibre samples, mounted horizontally. Temperature is shown at the surface and at different depths. The mass of the sample is continuously measured. From the raw data, we derive the temporal evolution of the mass loss rate due to pyrolysis. Different externally imposed heat fluxes are investigated (20, 30 and 50 kW/m(2)), onto dry and wet material. Afterwards, for the configuration of two particle board plates (0.025 m thick, 0.4 m wide and 2.5 m high), vertically mounted face to face is considered. Two different horizontal spacing distances between the two plates are studied (30.5 and 10.5 cm). The purpose of this set-up is to investigate the vertical upward flame spread with strong radiative heat feedback. To that purpose, the temporal evolution of surface temperature is measured over the height of the plates. The measurement data are used to test a pyrolysis model in numerical simulations. Copyright (C) 2010 John Wiley & Sons, Ltd