Qingsen Zhao

Selective Catalytic Reduction of NO by NH3 Over Fresh and Sulfated CuO/gamma-Al2O3 Catalysts

CuO/gamma-Al 2 O 3 granular catalysts were synthesized by the sol-gel method. Performance of the CuO/gamma-Al 2 O 3 catalysts for the selective catalytic reduction (SCR) was explored in a fixed bed adsorption system. The optimum temperature ranges for SCR of NO over the fresh CuO/gamma-Al 2 O 3 catalyst are 250~450degC. The maximum activity maintains near to 99% at 350degC. The operating temperature range is increased on the sulfated catalysts. The oxidation property becomes weak when the catalysts are sulfated. The transient behaviors of NH 3 and NO were also studied; it was found that the SCR reaction was zero order with respect to NH 3 and first order with respect to NO. The sulfation on the catalysts improves the adsorption capacity of NH 3 and reduces the adsorption capacity of NO. The adsorbed of NO has little influence on denitrification activity in the actual SCR process.

The Accurate Thermal Performance History Files of Wet Steam Turbine in Nuclear Power Plant

There are significant differences between the nuclear power plant turbine and the coal-fired power plant turbine. So the characterization and monitoring models for the coal-fired power plant turbine can not be reused in the nuclear power plant second loop. The unknown wet steam enthalpy and the characteristic of the turbine flow capacity were the two important obstacles for the nuclear power plant wet steam turbine. Based on the accurately measured test data, the accurate thermal performance history files was constructed using the small error heat balance method and the characteristic flow area (CFA). The accurate thermal performance history files were the base for the performance analysis, variable condition calculation, monitoring and diagnosis. The accurate thermal performance history files of Ling Ao unit 3 showed that the unit performance almost was excellent. But the CFA values and the efficiency indicated that some stages of intermediate pressure cylinder (IPT) had leakage in diaphragm, which decreased the unit output. The characteristic parameters of heat regenerative system and moisture separator reheaters system were almost close to the design values, which denoted that the performance of the two systems was acceptable. But the condenser back pressure was larger than the design values, which suggest that the performance was worse than the design condition.

The Research of Insufficient Output in TQNPC Unit 2

The revised electric power of TQNPC unit 2 was insufficient at the assessment test. The Hitachi supplier considered that the insufficient output was caused by the too large flow area of high pressure cylinder. After the nozzle modification the unit output had not been improved significantly. In this paper, the characteristic flow area (CFA) was used to evaluate the turbine flow capacity. The results showed that the CFA values of high pressure cylinder and low pressure cylinder were both too large, but also within the design margin (3-5%). The reason of insufficient output was not the mismatch with flow capacity. According to the nuclear power plant diagnosis and analysis models, the thermal performance of the hot side, the cold side and the thermal system was researched respectively. The performance of hot side and cold side were better than the design values, which was favor for the unit output. So the insufficient output was focus on the thermal system. Then the technical staffs took corresponding measures to transform the thermal system and then the unit output was improved finally.

DFT Study of NH3 and NO Adsorption on Copper-Aluminate Catalysts

The selective catalytic reduction (SCR) reaction belongs to the gas-solid multiphase reaction, and the adsorption of NH 3 and NO play an important role in the reaction. The adsorption behaviors of NH 3 and NO were studied with the diffuse reflectance infrared transform spectroscopy (DRIFTS) methods; these results showed that there were obvious adsorption phenomena of NH 3 and NO on the catalysts. NH 3 could be strongly adsorbed on the catalysts, resulting in coordinated NH 3 and NH 4 + . NO adsorption led to the formation of bridging bidentate nitrate, chelating bidentate nitrate, and chelating nitro. In this study, the interaction of NH 3 and NO molecules with the Cu 2+ present on the CuAl 2 O 4 (100) surface had been investigated by using a periodic density functional theory (DFT). The results showed that the adsorption of all the molecules on the Cu 2+ site is energetically favourable, whereas NO bound was more stronger than that of NH 3 with the adsorption site, and key information about the structural and energetic properties was also addressed.

Study on the Nitric Compounds during Coal Gasification

This investigation involved the formation and evolution of NO¿ HCN and NH3 during coal gasification. Since HCN and NH3 are the precursors of NOX, their summation are considered to show the characteristics of the precursors in this paper. The experiments were carried out in TGA with 25¿/min at atmospheric pressure. The releasing characteristics of the coal gasification species were inspected by the FTIR online instruments. The influence of coal particle size and gasification agents on the releasing characteristics of N-containing compounds was discussed. Results showed that small particle size was beneficial to form more HCN and NH3 during coal gasification in CO2, but not to NO; the higher concentration of CO2 could improve the shift reaction and consume NH3 and HCN faster; high temperature could increase the consecutive reaction velocity fast and make the consumed amount of NO exceeding the formation amount.