Validation of combustion modelling for practical combustion systems
Oxy-fuel combustion is considered a promising technology for reducing greenhouse gases emission through CO2 capture and storage techniques. In recent years there has been a large increase of the use of simulation tools, such as those based on Computational Fluid Dynamic (CFD). CFD calculations may be applied directly to the industrial scale of interest, thus avoiding scaling-up the results from lab-scale experiments.
The formation and emission of fine particles from biomass and coal combustion have received increasing attention in the last few years. Aerosols from fuels with high volatile sodium or potassium compounds, as biomass and bio-refuse feedstocks, are often dominated by a large submicron particle fraction, formed as a consequence of alkali volatilization in the combustion zone and the following condensation. The growing interest in these particles mainly owns to their contribution to environmental pollution on both urban and regional scale. This issue is potentially enhanced by the greater difficulties in filtering the ultrafine particulate than the coarser fraction, using the existing flue gas cleaning devices. Moreover, aerosols can be enriched in heavy metals volatilized in the combustion zone, as particularly observed in coal combustion. Fine particles, which in biomass combustion are mainly composed by chlorides and sulphates, also contribute to deposition (slagging and fouling) and corrosion phenomena on boiler walls and tube surfaces.
IFRF, ENEL and CPR undertook a joint project with the main objective of developing a suitable system and the related procedures for studying aerosol formation in co-combustion of coal and biomass.
This report contains the results of the experimental campaigns carried out by ENEA and International Flame Research Foundation (IFRF) in collaboration with The Department of Chemical Engineering, Industrial Chemistry and Materials Science (University of Pisa), during year 2011 about the program “Development and optimization of innovative systems for the real-time diagnostic of semi-industrial furnace operating in Oxy-coal combustion”. With this agreement, ENEA and IFRF had the opportunity to test the Optical Diagnostic of Combustion probes on the ENEL/IFRF Research facility at Livorno.
In this report, the plant, the probes, the operating conditions and the recorded signals by the ODC system during the oxycombustion experimental campaign on FOSPER, 3 MWth furnace, are reported. The detailed analysis of the signals is also performed and conclusions are drawn on the applicability of the diagnostic technique to industrial combustion system.
The report proposes a methodology for estimating the uncertainty in experiments and numerical simulations, to promote a constructive validation of computational approaches.
This paper reports part of the results of the campaigns performed on a low NOX burner, firing natural gas in oxy-fuel conditions. The results of combustion tests on burning natural gas with different flue gas recycle rates are presented, with a particular emphasis on NOX production that might affect retrofitting of oxy-fuel technology in conventional boilers.
The paper was presented at the 33rd International Symposium on Combustion.
This report presents the results of the first phase of the experimental programme carried out by ENEL and IFRF in the period from December 2008 to January 2009. Tests on the FOSPER furnace were initiated as part of the EU RFCS Friendly Coal project, with IFRF activity covered by ENEL and EU funding. The programme on FOSPER, mainly commissioning new oxy-firing capability, was a response to the pressing demand for data and information on pilot and semi-industrial scale.
The validation of mathematical models on semi-industrial scale plants plays a fundamental role in the development of new combustion technologies. Whilst in the past, the IFRF's semi-industrial scale Furnace #1 was regarded as a reference case for mathematic modellers requiring validation of their computer codes, the key facility is now the 3-5 MW furnace Fo.Sper. (Fornace Sperimentale–Experimental Furnace), a replica of Furnace #1.
The Members Research Project “Validation of combustion modelling for practical combustion systems” has as its objective the production of a large set of in flame measurements in different combustion conditions and the use of this data to validate advanced mathematical models.
In order to acquire reliable information from FOSPER, some preliminary experimental campaigns were carried out to test the furnace, the burners and the measurement instrumentation. This report describes the first two campaigns carried out by ENEL and the IFRF during November-December 2006 and June-July 2007, and includes a critical analysis of the data measured.
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