A Chemical Reactor Network for Oxides of Nitrogen Emission Prediction in Gas Turbine Combustor

This study presents the use of a new chemical reactor network(CRN) model and non-uniform injectors to predict the NOx emission pollutant in gas turbine combustor. The CRN uses information from Computational Fluid Dynamics(CFD) combustion analysis with two injectors of CH4-air mixture. The injectors of CH4-air mixture have different lean equivalence ratio, and they control fuel flow to stabilize combustion and adjust combustor's equivalence ratio. Non-uniform injector is applied to improve the burning process of the turbine combustor. The results of the new CRN for NOx prediction in the gas turbine combustor show very good agreement with the experimental data from Korea Electric Power Research Institute.

Influence of sulfation on CeO_2-ZrO_2 catalysts for NO reduction with NH_3

CeO2‐ZrO2 (CeZr) and sulfated CeO2‐ZrO2 (S‐CeZr) catalysts were prepared for the selective catalytic reduction of NO with NH3. The CeZr catalysts exhibited higher activity at low temperatures (< 200°C) and lower activity at high temperatures (> 200 °C) than the S‐CeZr catalysts. The sulfation ofCeZr was studied in terms of surface acidity, redox properties and NO adsorption‐desorption bytemperature‐dependent experiments and in situ infrared spectroscopy. S‐CeZr displayed high concentrationsof acidic sites and increased surface acidities, but poor reducibility compared with CeZr.The high acidity of S‐CeZr was attributed to the presence of Br?nsted acid sites, arising mainly fromthe surface sulfates. Because the surface was covered with sulfate species, S‐CeZr showed lower NOadsorption and weaker oxidation ability than CeZr. The adsorption of NH3 on the Br?nsted acid sites restricted the reaction with NO at low temperatures, but the selective catalytic reduction cycle occurred easily at relatively low temperatures (150 °C), and the weakly bound nitrite was partially activated on the S‐CeZr catalyst at relatively high temperatures (300 °C). The catalytic mechanisms for the CeZr and S‐CeZr catalysts at 150 and 300 °C were also studied.

Autotrophic Biofilters for Oxidation of Nitric Oxide

Carbon foam—a kind of new engineering material as packing material was adopted in three biofilters with different pore dimensions and adapted autotrophic nitrite nitrobacteria to investigate the purification of nitric oxide (NO) in a gas stream. The biofilm was developed on the surface of carbon foams using nitrite as its only nitric source. The moisture in the filter was maintained by ultrasonic aerosol equipment which can minimize the thickness of the liquid film. The liquid phase nitrification test was conducted to determine the variability and the potential of performance among the three carbon foam biofilters. The investigation showed that during the NO2^-—N inlet concentration of 200 g·L^-1·min^-1 to 800 g·L^-1·min^-1, the 24PPC (pores per centimeter) carbon foam biofilter had the greatest potential, achieving the NO2^-—N removal efficiency of 94% to 98%. The 8PPC and 18PPC carbon foam biofilters achieved the NO2^-—N removal efficiency of 15% to 21% and of 30% to 40%, respectively. The potential for this system to remove NO from a gas stream was shown on the basis of a steady removal efficiency of 41% to 50% which was attained for the 24PPC carbon foam biofilter at specified NO inlet concentration of 66.97 mg·m^-3 to 267.86mg·m^-3 and an empty-bed residence time of 3.5 min.

NO reduction by CO over TiO_2-γ-Al_2O_3 supported In/Ag catalyst under lean burn conditions

TiO2/γ-Al2O3 supported In/Ag catalysts were prepared by impregnation method,and investigated for NO reduction with CO as the reducing agent under lean burn conditions.The microscopic structure and surface properties of the catalysts were studied by N2 adsorption-desorption,X-ray diffraction,transmission electron microscopy,X-ray photoelectron spectroscopy,ultraviolet-visible spectroscopy,H2 temperature-programmed reduction and Fourier transform infrared spectroscopy.TiO2/γ-Al2O3 supported In/Ag is a good catalyst for the reduction of NO to N2.It displayed high dispersion,large amounts of surface active components and high NO adsorption capacity,which gave good catalytic performance and stability for the reduction of NO with CO under lean burn conditions.The silver species stabilized and improved the dispersion of the indium species.The introduction of TiO2 into the γ-Al2O3 support promoted NO adsorption and improved the dispersion of the indium species and silver species.

3D Simulation Research on Urea-SCR DeNO_x Catalyst for Diesel Engine

In order to reduce oxides of nitrogen （NOx） emanated from a diesel engine, a comprehensive urea selective catalyst reduction （SCR） DeNOx catalyst was modeled in which numerical simulations were used as a complementary tool for the experimental investigations to make the design decisions, and hence shorten the de- velopment process. In this approach, relevant conversion reactions were studied in 1D model, and the parame- ters obtained in this way were transferred to 3D simulations. According to the results of the study, the conver- sion of NO and NO2 increased with the increase in monolith solid temperature. With the increase in the ratio of NO2/NOx the conversion of NO, NO2 and NOx increased resulting in maximum reduction of NOxat the ratio of 1; beyond this ratio, the conversion of NO2 and NOx decreased; however, NO continued to be converted till the ratio was 1.8. The conversion of NOx decreased with the increase in space velocity.

Multiphoton lonization Spectrum of Nitrogen Oxide by D^2∑←X2П

The resonance-enhanced multiphoton ionization (REMPI) spectrum of NO has been obtained. The spectral lines can be attributed to NO D2∑←X2П transitions. NO molecules are ionized via the resonant intermediate D2∑ states and by (3+2) REMPI process.