Progress was made in hardware development, equilibrium calculations and with understanding combustion kinetics.
The design and construction of a plug flow, pressurized reactor is well underway. A literature search identified design and safety concerns for similar reactors. The vaporizer section was constructed. A prototype mixing valve was machined.
The thermodynamic equilibrium calculations are finished for ethanol-water volume fractions ranging from 0 to 0.5; equivalence ratios ranging between 0.4 and 1.6 (fuel lean to fuel rich); and pressures ranging from 1 to 16 atmospheres. The calculations show the influence of the water-gas shift reaction on the increased oxidation of carbon monoxide with increased fuel water content. The impact of water on NO formation can be roughly explained by the sensitivity of the thermal NO mechanism to decreasing combustion temperature with increasing water-fuel content.
Good progress has been made understanding the gas phase and surface reactions of ethanol. Three major pathways are present for gas-phase ethanol combustion based on the three radicals formed when an H atom is stripped from one of the three backbone atoms in the molecule (C1, C2 or O). Acetaldehyde, ethene and formaldehyde are stable intermediate products depending on the pathway, with the acetaldehyde path dominating.
In the presence of the catalyst, hydrogen atoms are stripped off the ethanol molecule because of the proximity effect of the platinum (Pt) surface. Pt surface reactions produce stable products, radicals, and heat. The chemical species that can desorb include OH radicals. Products, radicals and heat diffuse from the surface to unreacted gas-phase ethanol where ignition occurs.
HCT is a finite-difference code that calculates one-dimensional time-dependent problems involving gas hydrodynamics, transport, and detailed chemical kinetics. A one-dimensional catalytic surface reaction model is under development for addition to the code.