TY - JOUR
T1 - Optimization of a catalytic combustor using electrosprayed liquid hydrocarbons for mesoscale power generation
AU - Kyritsis, Dimitrios C.
AU - Coriton, Bruno
AU - Faure, Fabien
AU - Roychoudhury, Subir
AU - Gomez, Alessandro
N1 - Funding Information:
We acknowledge Dr. R.S. Tranter of the University of Illinois at Chicago for his consulting in setting up the GC/MSD/FID, Mr. R.W. Dean of PCI for his assistance with the micro-GC measurements, Mr. N. Bernardo of Yale University for machining the hardware, and Mr. P.A. Dobrowolski of Yale University for acquiring the photograph of Fig. 1 . The support of DARPA under Grant No. DAAD19-01-1-0664 (Dr. Richard J. Paur, Contract Monitor) is gratefully acknowledged. Microlith is a trademark of Precision Combustion Inc.
PY - 2004/10
Y1 - 2004/10
N2 - A detailed study on the performance of a combustor to be used as a portable power source for mesoscale applications is presented. The burner operation is based on the combination of liquid fuel electrospray injection with combustion through a stack of catalytically coated grids, for the delivery of ≈100W of thermal power. The main design challenges relate to emission minimization, versatility for the coupling to power conversion modules, thermal management, and miniaturization. Combustion efficiency and emission reduction were pursued through catalyst optimization. Using two-dimensional infrared temperature measurements and gas chromatography/mass spectrometry/flame ionization detection exhaust gas analysis, we established a catalyst formulation which provides in excess of 99% combustion efficiency, based on the conversion of the parent hydrocarbon and air to CO2 and H2O. Remarkably, reliable catalyst operation was achieved even using the notoriously polluting JP8, with as many as 1200 ppm of sulfur naturally present in the fuel. CO emission is undetectable and catalytic surface temperatures fall in the 900-1500 K range, which is appropriate for coupling with thermal-to-electric energy conversion systems, such as thermoelectric and Stirling engines. The burner was tested for prolonged operation (500 h) for catalyst stability and aversion to coking, even under conditions of high air inlet temperature, to simulate conditions of heat recuperation that are indispensable to the design of high efficiency mesoscale devices. Droplet sizes reveal the need for fuel distributor multiplexing to minimize vaporization time and therefore the size of the necessary preheat chamber. The results of the characterization of a prototypical device led to an improved design utilizing multijet electrospray injection from a single fuel source, an electrospray ring extractor, and whirl, side-port air injection. In addition to reduced emissions and better temperature uniformity, this improved design relying on conventional fabrication resulted in optimal performance in a volume on the order of 10 cc.
AB - A detailed study on the performance of a combustor to be used as a portable power source for mesoscale applications is presented. The burner operation is based on the combination of liquid fuel electrospray injection with combustion through a stack of catalytically coated grids, for the delivery of ≈100W of thermal power. The main design challenges relate to emission minimization, versatility for the coupling to power conversion modules, thermal management, and miniaturization. Combustion efficiency and emission reduction were pursued through catalyst optimization. Using two-dimensional infrared temperature measurements and gas chromatography/mass spectrometry/flame ionization detection exhaust gas analysis, we established a catalyst formulation which provides in excess of 99% combustion efficiency, based on the conversion of the parent hydrocarbon and air to CO2 and H2O. Remarkably, reliable catalyst operation was achieved even using the notoriously polluting JP8, with as many as 1200 ppm of sulfur naturally present in the fuel. CO emission is undetectable and catalytic surface temperatures fall in the 900-1500 K range, which is appropriate for coupling with thermal-to-electric energy conversion systems, such as thermoelectric and Stirling engines. The burner was tested for prolonged operation (500 h) for catalyst stability and aversion to coking, even under conditions of high air inlet temperature, to simulate conditions of heat recuperation that are indispensable to the design of high efficiency mesoscale devices. Droplet sizes reveal the need for fuel distributor multiplexing to minimize vaporization time and therefore the size of the necessary preheat chamber. The results of the characterization of a prototypical device led to an improved design utilizing multijet electrospray injection from a single fuel source, an electrospray ring extractor, and whirl, side-port air injection. In addition to reduced emissions and better temperature uniformity, this improved design relying on conventional fabrication resulted in optimal performance in a volume on the order of 10 cc.
KW - Catalytic combustion
KW - Electrospray
KW - JP8
KW - Microcombustion
KW - Microlith
KW - Power generation
UR - http://www.scopus.com/inward/record.url?scp=4944250776&partnerID=8YFLogxK
U2 - 10.1016/j.combustflame.2004.06.010
DO - 10.1016/j.combustflame.2004.06.010
M3 - Article
AN - SCOPUS:4944250776
SN - 0010-2180
VL - 139
SP - 77
EP - 89
JO - Combustion and Flame
JF - Combustion and Flame
IS - 1-2
ER -
