Three reports based on work done last year on solid fuel characterisation are now available in the Current Reports section of the IFRF web site.
Review of methodologies for coal characterisation critically describes the most common procedures for characterising the behaviour of solid fuels for utilization in industrial pulverized coal burners. Specific procedures for solid fuel characterisation are elaborated to study the effect on combustion behaviour of fuel properties and composition as well as operating conditions.
The adoption of non-standard procedures is useful for providing parameters for large scale applications (advanced models, plant design and optimization). Procedures developed by IFRF in previous activities, the arrangement of the new Isothermal Plug Flow Reactor at Livorno, and the exploratory experimental campaign during 2010, highlight the critical points in the characterisation of solid fuels.
Review of solid fuels combustion models for the determination of reactivity parameters reviews the most common models for devolatilization and char oxidation, remarks on the advantages and drawbacks of each approach, compares the performances, and suggests the applicability ranges. Some examples from literature and from previous IFRF reports (based on Isothermal Plug Flow Reactor runs on different solid fuels) are commented upon.
The research needs are defined to underline the importance of fuel characterisation: devolatilization (volatile yield, composition of pyrolysis products) and char properties (size, morphology, reactivity), both fundamental parameters to be evaluated after experimental tests under conditions similar to those of pulverized fuel combustors – high temperature and heating rate.
Two specific models (one for devolatilization and one for char oxidation) are described in detail, highlighting the parameters needed, the numerical issues and the optimization procedure based on experimental data.
Description of the Isothermal Plug Flow Reactor and the experimental procedures for combustion studies on solid fuels provides an overview of the Isothermal Plug Flow Reactor at Livorno. Geometrical, operating and diagnostic parameters are presented, and details are provided of combustion related studies for solid fuels, such as devolatilization and char oxidation.
The high temperature and heating rate of the IPFR, which has undergone qualification activities such as the upgrading of specific components and diagnostic tests, and the experimental procedures which have been carried out on it, make the IPFR a superior facility for providing data and parameters for advanced models of pulverized fuel combustors as well as innovative plants (e.g. oxyfiring and gasification). With the IPFR, devolatilization and char oxidation may be studied under conditions similar to those of large scale furnaces, allowing reliable and qualified parameters to be obtained for inputting the IFRF’s Solid Fuel Database, and validating advanced and comprehensive models.
Also published today, and entitled Retrofitting oxy-fuel technology in a semi-industrial plant: Flame characteristics and NOX production from a low NOX burner fed with natural gas, is a paper presented by IFRF Senior investigator Giovanni Coraggio at the 33rd International Symposium on Combustion in Beijing last year.
Next week the IFRF’s Solid Fuel Database will be made available online, together with some new data sets and methodologies for obtaining kinetics to be used in comprehensive CFD codes for modelling of pulverized fuel combustion.