Laser induced fluorescence measurements and modeling of nitric oxide in high-pressure premixed flames

Laser-induced fluorescence (LIF) has been applied to the quantitative measurement of nitric oxide (NO) in premixed, laminar, high-pressure flames. Their chemistry was also studied using three current kinetics schemes to determine the predictive capabilities of each mechanism with respect to NO concentrations. The flames studied were low-temperature (1600 less than T less than 1850K) C2H6/O2/N2 and C2H6/O2/N2 flames, and high temperature (2100 less than T less than 2300K) C2H6/O2/N2 flames. Laser-saturated fluorescence (LSF) was initially used to measure the NO concentrations. However, while the excitation transition was well saturated at atmospheric pressure, the fluorescence behavior was basically linear with respect to laser power at pressures above 6 atm. Measurements and calculations demonstrated that the fluorescence quenching rate variation is negligible for LIF measurements of NO at a given pressure. Therefore, linear LIF was used to perform quantitative measurements of NO concentration in these high-pressure flames. The transportability of a calibration factor from one set of flame conditions to another also was investigated by considering changes in the absorption and quenching environment for different flame conditions. The feasibility of performing LIF measurements of (NO) in turbulent flames was studied; the single-shot detection limit was determined to be 2 ppm

Degradation kinetics of resorcinol by Enterobacter cloacae isolate

Resorcinol was utilized as the sole carbon and energy source by Enterobacter cloacae (identification by 16S rDNA nucleotide sequencing Genbank Accession Number JN093148). The different concentration of resorcinol utilized by the bacterial isolate ranged between 55 and 220 mg l-1 at 30°C and pH of 7.0. It was observed that the batch experimental results were best fitted for Michaelis-Menten and Monod models (for 220 mg l-1 resorcinol) with time under defined conditions. The kinetics constants for the Michaelis-Menten equation (enzyme kinetics) were Km = 11.00 mM and Vmax = 0.03 mM min-1 and for the Monod equation (growth kinetics) was μmax = 0.0371 h-1 in the inhibitory region and KS = 22.09 mg l-1. It was assumed that enzyme reactions limit biomass production (Monod kinetics) during resorcinol degradation by E. cloacae. The enzyme kinetic model (Michaelis-Menten) used was fit to the resorcinol degradation profiles with a set of model parameters such as using pre-induced E. cloacae cells on 220 mg l-1 resorcinol

Modeling the Feasibility of Using Solar Thermal Systems for Meeting the Heating Requirements at Corn Ethanol Production Facilities

While ethanol use as a vehicle fuel has been promoted as a renewable alternative to fossil fuels, current production methods of ethanol from corn feedstock rely heavily on the combustion of nonrenewable fuels such as natural gas. Solar thermal systems can provide a renewable energy source for supplying some of the heat required ethanol production. In this paper, a model to analyze the feasibility of using solar thermal energy to reduce natural gas consumption in ethanol production is described and applied. Sites of current ethanol production facilities are used to provide a realistic analysis of the economic feasibility of using solar thermal energy in the ethanol production process. The results show that it is not reasonable to expect to replace all of the natural gas consumption in the heating processes in ethanol production but that application of solar thermal energy can be applied to a specific subsystem such as the preheating of boiler makeup water. Profitability of systems for replacing a fraction of the natural gas is analyzed. It is found that both location and local natural gas prices are important in determining whether to pursue such a project and that solar thermal systems should have long-term profitability

An energy and exergy study of a solar thermal air collector

A solar flat plate air collector was manufactured in the north of Iran, and connected to a room as the model to study the possibility of using such solar heating systems in the northern parts of Iran. This collector was tested as a solar air heater to see how good it could be for warming up the test room during the winter. The experimental data obtained through accurate measurements were analyzed using second law approach to find the optimum mass flow rate, which leads to the maximum exergy efficiency. It was found that for the test setup at the test location, a mass flow rate of 0.0011 kg/s is the optimum mass flow rate for tested conditions which leads to the highest second law efficiency