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Abstract  

The recombination of hydrogen and oxygen in technical gaseous waste of nuclear power plants in enlarged scale experiment has been studied on the basis of our previous work.1 The catalyst and its best operating conditions for recombination of hydrogen and oxygen determined in a small scale experiment were demonstrated and tested. The results show that the data obtained in an enlarged scale experiment agreed well with that of in a small scale test. The recombination rate of H2 and O2 was higher than 98.3% and 99.98% respectively. After recombination, the residual concentrations of H2 and O2 in waste gas were O2<3 ppm, H2<400 ppm. The Pd-Al2O3 catalyst and operating conditions determined for gaseous waste processing of nuclear power plants were satisfactory.

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Abstract  

The decomposition reaction kinetics of the double-base (DB) propellant (No. TG0701) composed of the mixed ester of triethyleneglycol dinitrate (TEGDN) and nitroglycerin (NG) and nitrocellulose (NC) with cerium(III) citrate (CIT-Ce) as a combustion catalyst was investigated by high-pressure differential scanning calorimetry (PDSC) under flowing nitrogen gas conditions. The results show that pressure (2 MPa) can decrease the peak temperature and increase the decomposition heat, and also can change the mechanism function of the exothermal decomposition reaction of the DB gun propellant under 0.1 MPa; CIT-Ce can decrease the apparent activation energy of the DB gun propellant by about 35 kJ mol−1 under low pressure, but it can not display the effect under high pressure; CIT-Ce can not change the decomposition reaction mechanism function under a pressure.

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Journal of Thermal Analysis and Calorimetry
Authors: Y. Y. Di, Z. C. Tan, L. W. Li, S. L. Gao, and L. X. Sun

Abstract

Low-temperature heat capacities of a solid complex Zn(Val)SO4·H2O(s) were measured by a precision automated adiabatic calorimeter over the temperature range between 78 and 373 K. The initial dehydration temperature of the coordination compound was determined to be, T D=327.05 K, by analysis of the heat-capacity curve. The experimental values of molar heat capacities were fitted to a polynomial equation of heat capacities (C p,m) with the reduced temperatures (x), [x=f (T)], by least square method. The polynomial fitted values of the molar heat capacities and fundamental thermodynamic functions of the complex relative to the standard reference temperature 298.15 K were given with the interval of 5 K.

Enthalpies of dissolution of the [ZnSO4·7H2O(s)+Val(s)] (Δsol H m,l 0) and the Zn(Val)SO4·H2O(s) (Δsol H m,2 0) in 100.00 mL of 2 mol dm−3 HCl(aq) at T=298.15 K were determined to be, Δsol H m,l 0=(94.588±0.025) kJ mol−1 and Δsol H m,2 0=–(46.118±0.055) kJ mol−1, by means of a homemade isoperibol solution–reaction calorimeter. The standard molar enthalpy of formation of the compound was determined as: Δf H m 0 (Zn(Val)SO4·H2O(s), 298.15 K)=–(1850.97±1.92) kJ mol−1, from the enthalpies of dissolution and other auxiliary thermodynamic data through a Hess thermochemical cycle. Furthermore, the reliability of the Hess thermochemical cycle was verified by comparing UV/Vis spectra and the refractive indexes of solution A (from dissolution of the [ZnSO4·7H2O(s)+Val(s)] mixture in 2 mol dm−3 hydrochloric acid) and solution A’ (from dissolution of the complex Zn(Val)SO4·H2O(s) in 2 mol dm−3 hydrochloric acid).

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Abstract

Phase change materials (PCM) have been extensively scrutinized for their widely application in thermal energy storage (TES). Paraffin was considered to be one of the most prospective PCMs with perfect properties. However, lower thermal conductivity hinders the further application. In this letter, we experimentally investigate the thermal conductivity and energy storage of composites consisting of paraffin and micron-size graphite flakes (MSGFs). The results strongly suggested that the thermal conductivity enhances enormously with increasing the mass fraction of the MSGFs. The formation of heat flow network is the key factor for high thermal conductivity in this case. Meanwhile, compared to that of the thermal conductivity, the latent heat capacity, the melting temperature, and the freezing temperature of the composites present negligible change with increasing the concentration of the MSGFs. The paraffin-based composites have great potential for energy storage application with optimal fraction of the MSGFs.

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Abstract  

The recombination of hydrogen and oxygen in technical gaseous waste of nuclear power plants has been studied. A highly efficient catalyst for reacting H2 with O2 to form water was prepared. Various operating conditions and factors affecting the recombination of H2 and O2 were tested and the best conditions were determined. Results show that the Pd–Al2O3 catalyst prepared had very good characteristics. The recombination rate of H2 and O2 was higher than 98.3% and 99.9%, respectively. After recombination, residual concentrations of H2 and O2 in waste gas were O2<3 ppm, H2<400 ppm. The Pd–Al2O3 catalyst and operating conditions determined for gaseous waste processing of nuclear power plants were satisfactory.

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