FLOX burner

Bandi A, Baumgart F, Stirling engine with flox burner fuelled with fast pyrolysis with fast pyrolysis liquid , These proceedings... 

Bandi A., and F, Baumgart (2000), Fast pyrolysis liquid feed to a FLOX burner. In Proceedings of Progress in Thermo-chemical Biomass Conversion, Tyrol, Austria, 17-20 September. 

Stirling Engine with Flox Burner Fuelled With Fast Pyrolysis Liquid... 

ABSTRACT Fast pyrolysis liquid was combusted with a modified propane gas FLOX burner (WS) mounted to a Stirling CHP unit (SOLO 25 kW ). The propane burner was modified by an air pressure atomiser designed for pyrolysis liquids. Nearly 110 hours of operation with different fuel loads have been achieved, engine performance and emissions were recorded. The Stirling tests proved that pyrolysis liquids can be burned efficiently and with low emissions in a FLOX mode operating burner attached to a Stirling CHP unit. 

Within this project ZSW designed and realised an injection-atomisation system for BCO. A WS propane burner [1.2] was modified with a ZSW atomiser and attached to a SOLO Stirling engine 161 (4-9 kW 10-25 kW, ,) [3]. This paper presents experimental results on the burning of BCO in a FLOX burner and in a Stirling CHP unit with a FLOX burner. 

COMBUSTION EXPERIMENTS WITH A STIRLING CHP UNIT EQUIPPED WITH A FLOX BURNER... 

Combustion experiments of BCO in a Stirling CHP unit with FLOX burner were conducted for nearly 110 hours with difTerent loads. 

When the kinetics of the combustion reactions are taken into consideration, there are also other design shapes and operating ranges for the FLOX burners. Even undesired spontaneous reactions between air and fuel can be suppressed, inasmuch as temperature in the mixing zone is kept low or flow velocities are well above flame... 

A comparison of the combustion temperatures in flame- and in FLOX -mode should clearly show the reduction of the temperature peaks. Figure 23.13 shows, in the upper diagram, the temperature field of a 400 kW burner in a furnace at 1200°C fired with cold air in flame mode. In the second diagram, the same burner is operated with air at 600°C, but the fuel input is reduced to 245 kW to take into account the preheating and thereby keeping the net heat input constant. The temperature field of a 200 kW FLOX burner using preheated air at 950°C is represented in the bottom diagram. 

The cold air burner exhibits the typical pattern of cold air flames with expected peaking temperatures about 2120°C. In the case of the FLOX burners, the temperature field is substantially modified and the highest temperature is no longer close to the burner nozzle. In spite of the high air preheat the peak temperature is 1745°C, well below the case of the cold air burner. 

The temperature peaks are the basic reason for the thermal nitrogen oxide formation and this explains why, with FLOX -burners, the nitrogen oxide emissions can be much lower than with cold air burners, in spite of higher air preheat. 

Several thousand high velocity FLOX burners (especially recuperative natural gas burners with efficient, built-in air preheating) are in fact satisfactorily firing in free flame or in radiant tubes in heat treatment and or heating furnaces [14,18,19]. In other circumstances, however, air and fuel jets from the burner nozzles cannot follow the basic formulae of the free jet and recirculation of flue gases is not unconditional. 

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