• Reigniting the… mid-1980s to mid-1990s

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      Jacques Dugue

Hello MNM readers!

Back in 1986, IFRF was looking for a French investigator in order to maintain the then ‘tradition’ of having investigators from the UK, the Netherlands and France (i.e. the three founding nations of the organisation in 1948) on the Research Team.  Having met in France an attractive woman who turned out to be Dutch (my wife today ;-), I was looking for employment in the Netherlands to get to know the country and its culture.  I was interviewed by Peter Roberts (then Director) and Jan van Langen (then General Secretary) – both of whom seemed relieved to find a Frenchman who appeared to understand them and whom they could understand!  For my part, I was immediately excited by the thought of working in an international organisation represented in Europe, North America and Japan, and with a team of investigators from nearly 10 countries.  From these mutual premises started a collaboration that lasted 10 years…

The decade from 1986 to 1996 was especially rich for both industrial combustion research and for IFRF’s activity within that area.  In this period, the IFRF received significant funding from the International Energy Agency to carry out multiple research projects related to coal combustion (the ‘Air Pollution’ – AP – and ‘Coal Characterisation’ – CC – series of experiments).  The IFRF benefited also from funding from the European Commission (the ‘Multi-Fuel Burner’ – MFB – series of experiments), the US Gas Research Institute (the ‘Scaling 400’ study) and several industry-led international consortia aiming to reduce NOx emissions in glass tanks (the ‘NGNOx’ project), cement rotary kilns (the ‘CEMFLAM’ project) and gas-oxygen burners (the ‘OXYFLAM’ project).

In the early 1980s, laser based diagnostics were beginning to find applications in combustion research at the laboratory scale, and one of my first tasks on joining IFRF was to commission a new Laser Doppler Velocimeter that had been purchased for velocity measurements in flames.  We quickly learned that the fluctuations in the refractive index inside the IFRF’s pilot-scale furnace made the laser beams wander significantly, making the measurements impossible beyond a few centimetres in front of the LDV probe.  An effective solution was developed by purchasing a miniaturised LDV ‘head’ coupled to the laser with optical fibres.  A water-cooled probe was developed to protect the LDV head.  This arrangement proved successful and helped us perform velocity measurements rapidly and reliably in gas, oil and coal flames.  Although LDV measurements had been conducted successfully at a laboratory-scale elsewhere, IFRF appeared to be the first to perform such measurements in semi-industrial scale (i.e. 2MWth+) flames.  Our solution was presented at the 6th International Symposium on Application of Laser Techniques to Fluid Mechanics in Lisbon during 1992, and later sold to other organisations in Europe and the USA.  For those wanting to know more, please request the following paper from the IFRF archives:

  • Laser velocimetry in semi-industrial natural gas, oil and coal flames by means of a water-cooled LDV probe (Dugué, Weber), 6th International Symposium on Application of Laser Techniques to Fluid Mechanics, Lisbon, Portugal, 1992 – IFRF Doc. No. K 70/y/48

In parallel to my activities on in-flame measurement techniques, I worked with Roman Weber on the ‘Near Field Aerodynamics’ – NFA – programme to investigate the effect of combustion on swirling flows.  This extensive programme concluded a long series of experiments on swirling flames that found its roots at IFRF in the 1960s with the work of Professors Beér, Chigier and Leuckel, later followed in the 1980s by Hagiwara, Schmid and Bortz.  These studies demonstrated the effect of Swirl number, burner quarl geometry, bluff body ratio and fuel injector design on flame shape and stability and found their application in numerous industrial burner designs.  Several publications were prepared, the most comprehensive one being Roman’s 1992 review paper in Progress in Energy and Combustion Science,available from the archive:

  • Combustion accelerated swirling flows in high confinements (Weber, Dugué),  Prog. Energy Combust. Sci. 1992, Vol. 18, pp349 – IFRF Doc. No. K 70/y/36

Meanwhile, the Multi-Fuel Burner series of experiments was also producing notable results.  The first phase (MFB-1), carried out in 1990, focussed on fuel staging and external flue gas recirculation on a natural gas burner.  Interestingly (and somewhat to our surprise), we discovered that the best performance in terms of NOx emissions was achieved with a very high fuel-staging ratio, and particularly when the staging ratio was 100%, meaning that all the fuel was injected in staging lances around the burner periphery.  These results helped us understand what was soon-after referred to as ‘flameless combustion’.

The MFB-2 trials (1991) were directed at the investigation of residual oil combustion in air-staged burners.  As with most experiments of that time, detailed in-flame measurements were taken for the purpose of validating computational fluid dynamics (CFD) modelling.  This led us to collaborate with the University of Erlangen-Nuremburg on the use of Phase Doppler Velocimetry to characterise the velocity and droplet size distribution of heavy fuel oil sprays issued from Y-jet atomisers.  The Institute of Energy awarded in 1994 a prize for the publication of this innovative work :

  • Characterisation of semi-industrial-scale fuel-oil sprays issued from a Y-jet atomiser,(Sayre, Dugué, Weber, Domnick, Lindenthal), Journal of the Institute of Energy, Vol. 67 (no 471), pp70-77, 1994 – IFRF Doc. No. K 70/y/75

The following reports in IFRF’s archive may prove interesting to those who want to know more about the MFB programme:

  • Development of multi-fuel low-NOx burner technology: Phase 1: Natural gas burner – results of the MFB-1 investigation (Dugué, Saponaro, Weber) – IFRF Doc. No. F 10/y/2, 1991
  • Development of multi-fuel low-NOx burner technology: Phase 2: Residual fuel oil burner – results of the MFB-2 investigation (Sayre, Dugué, Weber) – IFRF Doc. No. F 10/y/4, 1992
  • Development of multi-fuel low-NOx burner technology: Phase 3: Oil and gas burner – results of the MFB-3 investigation (Sayre, Dugué, Weber) – IFRF Doc. No. F 10/y/6, 1994

The GRI-funded ‘Scaling 400’ study that followed the MFB series of experiments brought more opportunities for IFRF to investigate flames with deep staging and separate jets.  I still have strong memories of watching near flameless combustion in a 12 MWth burner with 100% fuel staging in a John Zink pilot-scale furnace in Tulsa, Oklahoma, in 1993!  The following year, we had the honour and privilege to be the first users of the Burner Engineering Research Laboratory located in the famous Sandia labs in Livermore, California to perform the 300 kW scale experiments:

  • Scaling characteristics of aerodynamics and low NOx properties of industrial natural gas burners.  The Scaling 400 Study.  Part IV: The 300 kW BERL test results (Sayre, Lallemant, Dugué and Weber) – IFRF Doc. No. F 40/y/11, 1994

Roman Weber, in his ‘Reigniting’ article last month, pointed you to some other key publications from this study, so I won’t repeat those references here.

The concept of separate fuel- and oxidant-jets was further developed in the programme of the OXYFLAM industrial consortium, which was established in 1994.  Configurations with various fuel and oxygen separation and injection velocities showed how to transition from the usual high-NOx flames to flameless ultra-low-NOx emissions.  The analysis of these results became the basis for my first patent after joining Air Liquide in July 1996, but that is another story…  The first unrestricted publication from the OXYFLAM consortium was in the Journal of the Institute of Energy in September 2000:

  • Flame structure, heat transfer and pollutant emissions characteristics of oxy-natural gas flames in the 0.7-1 MW thermal input range (Lallement, Breussin, Weber, Ekman, Dugué, Samaniego, Charo, Van den Hoogen, Van der Bemt, Fujisaki, Imanari, Nakamura, Iino), Journal of the Institute of Energy, Vol. 73, No.496, pp 169-182, September 2000 – IFRF Doc. No. K 70/y/128

Looking back on my 10 years at IFRF, we were all young investigators driven by our common task of further developing industrial combustion science.  We felt that we were on a mission!  We spent a lot of time together at work, but also during week-ends with our families.  As a result, strong bonds developed between many of us and these remain today.  Having Roman as manager was also an important reason for my long stay.  Roman was a unique leader, taught us a lot and helped us grow.  These were 10 excellent years of hard work, enjoyment and friendship.

Since leaving the IJmuiden facilities in 1996, I have maintained a close association with IFRF and held various positions.  As a combustion and fired-equipment practitioner, the IFRF network has been a fantastic forum that has helped me learn from my peers.  IFRF’s vision “to be the international reference point for industrial combustion that is safe, clean and efficient” remains as valid today as it was in 1948.

Long live IFRF!