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The influence of fuel characteristics in the formation of NO during combustion of methyl ester in oil-burner industrial boilers is presented in this paper. Under strictly controlled conditions of combustion, NO formation shows great susceptibility to biodiesel density, ignition delay, oxygen concentration, and adiabatic flame temperature. Results show that the adiabatic flame temperature affects NO formation more than the other variables, and the level of this pollutant exponentially increases with this ideal temperature for combustion. It is also shown that (a) NO formation during combustion of methyl esters linearly change with fuel density, (b) the increase of the combustion pressure reduces the effect of the density on NO formation, (c) the influence of the fuel cetane number on NO formation is intrinsic because it remains constant even when the quality of combustion is enhanced, and (d) in fuel-lean flames, oxygen of the biodiesel chemical structure increases the NO level.

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Mesoporous MCM-48 silica was synthesized by templating method and the structure of particles was characterized by XRD, TEM and N 2 adsorption techniques. The surface modification of particles in order for introducing into PSF matrix was performed by dimethyldichlorosilane (DMDCS) silylation agent. SEM images of as-synthesized and modified MCM-48/PSF MMMs indicate that in the modified MCM-48 silica particles adhered well to the PSF matrix and that the synthesized MMMs were defect free. The incorporation of MCM-48 particles in to the PSF matrix and also surface coating of these MMMs by polydimethylsiloxane (PDMS) were performed. The quality of surface coating was investigated by SEM images and permeability tests. For all gases tested (N 2 , CO 2 , CH 4 and O 2 ), the permeabilities increased in proportion to the weight percent of MCM-48 present in the film and the calculated CO 2 /CH 4 and O 2 / N 2 selectivities of PDMS coated membranes showed enhancement in ideal and actual selectivities both.

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