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Table of Content
25 December 1979, Volume 30 Issue 2
    化工学报
    Correlation of the Recent Ideal Gas Heat Capacity Data with Temperature
    Ma Pei-sheng Gao Ming-shu Jiang Bi-yun Zhang Jian-hou Department of Chemical Engineering, Tianjin University
    1979, 30(2):  109-132. 
    Abstract ( 634 )   PDF (1343KB) ( 558 )  
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    The four coefficients A, B,C and D of the correlation of ideal gas heat capacity, Cpo =A+BT + CT2 + DT3, were determined for 435 substances by the method of least squares with a digital computer, on the bases of the recently published Cpo data during the period of 1968 to 1978. The average percent deviation of the calculated Cpo from the experimental value is 0.160. The substances were selected according to their relative importance in fundamental chemical industries. Amongst these, either their heat capacity coefficients have not been published in the literature or their heat capacity coefficients are revised in the present work by using recently available published experimental data.
    A Sequential Procedure for Optimal Discrimination among Rival Rate Models for the Reaction of Synthesis of Ammonia on "A" Catalysts
    Liu De-ming Zhao Zhi-liang Huang Zi-xing Wu Xi-jun Research Institute of Nanjing Chemical Co.
    1979, 30(2):  133-142. 
    Abstract ( 543 )   PDF (562KB) ( 154 )  
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    This paper describes the study of optimal discrimination in detail among rival models for the reaction of synthesis of ammonia on "A" catalysts. For this purpose the sequential procedure has been applied, the parameters in candidate models have been preliminarily estimated, and rival models have been screened with proposed criteria. The discrimination was achieved. One of the models was found superior to the others and was finally retained. This paper also deals with the selection of algorithms for least-squares fitting, the details of technical matters in discrimination procedure and the criteria for identification of models.
    The Dynamics of Fast Fluidization
    Li You-chou Chen Bing-yu Wang Feng- ming Wang Yong-sheng Mooson Kwauk Institute of Chemical Metallurgy Acadetnia Sinica
    1979, 30(2):  143-152. 
    Abstract ( 599 )   PDF (493KB) ( 349 )  
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    Experiments on the dynamics of fast fluidization were carried out in a 100mm-diameter plexiglas column, 8 meters in height, on FCC catalyst, alumina powder, iron ore concentrate and fine pyrites cinder. Based on the rapid formation and dissolution of dense strands or clusters of solids dispersed in a continuum of dilute phase, a physical flow model of fast fluidization has been proposed leading to a first-order differatial equation, the solution of which yields a four-parameter equation of voidage distribution along the bed height z The integrated average voidage e throughout the whole bed height may be calculated by the following formula It has been found that computed values are in good agreement with those determined experimentally.
    A Study on the Vapor-Liquid Equilibrium for the System Containing Iodide
    Hu Ying Ying Xu-gen Zhang Hung-zhe Institute of Chemical Engineering of Shanghai
    1979, 30(2):  153-164. 
    Abstract ( 543 )   PDF (651KB) ( 186 )  
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    This paper reports the results of studying on the vapor liquid equilibrium for the systems containing iodide. Based on the data of a series of binary systems and a ternary system determined by ourselves, we studied the following two problems, (a )Among the four variables, temperature, pressure, liquid and vapor compositions, we were able to predict anyone of them from the other three by use of thermodynamic method. This method was also proved to be helpful to test the thermodynamic consistancy of the experimental data. (b) We attempted to correlated these binary data and predict the properties of multicomponent systems. Our results indicated that although aqueous hydrogen iodide is a strong electrolytic solution, by use of NRTL equation and expanding its parameters into polynomial series of temperature, it was able to predict multicomponent equilibrium from binary data.
    Olefins Manufacture from Vacuum Gas Oil in Tubular Furnace
    Cai Hui-lin Zhang Zai-yu Mao Wen-xing Wang De-liang Shi Xian-reng Beijing Research Institute of Chemical Industry
    1979, 30(2):  165-176. 
    Abstract ( 709 )   PDF (485KB) ( 392 )  
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    Low sulfur, high paraffin content and low aromaticity are the characteristics of some Chinese crudes. The vacuum gas oil obtained from these crudes have similar properties and therefore excellent cracking performance is to be expected. The pyrolysis kinetics and product yield pattern of the vacuum gas oil have been studied in a bench scale unit having about 2 kg/h hydrocarbon throughput capacity, where the temperature and pressure are profile controlled. Based on the data from experiments on bench scale unit, pilot plant and commercial pyrolysis furnace, parameters of the reaction rate constant equation for vacuum gas oil cracking have been determined, and the curves and equations correlating the feedstock properties and operating conditions against main products yields have also been expressed. A semi-commercial pilot plant of about 100 kg/h hydrocarbon throughput capacity, is used to confirm the products yield pattern and study the process technology, particularly to observe the coking tendency of the pyrolysis coil and the operating performance of the transfer line exchanger quenching device. It is found that at medium severity, with steam to oil ratio 0.75-1.00, residence time 0.4-0.5 sec., hydrocarbon partial pressure 0.8 kg/cm2,the main products yields are as follows, ethylene 22.5-23.0%, propylene 16.0-17.5%,butadiene 4.7-5.2%, heavy fuel oil 10-12%. The yields are similar to those obtained from the Middle East atmospheric gas oil cracking. Thus it is proved that the Chinese vacuum gas oil is a competitive feedstock for the manufacture of lower olefins in tubular pyrolysis furnace.
    Study of the Nature of Active Sites on the Catalysts of Pt-Al_2O_3 System by CS_2 Poisoning Method
    Yang Xi-yao Pang Li Department of Chemistry, Beijing University
    1979, 30(2):  177-184. 
    Abstract ( 608 )   PDF (119KB) ( 198 )  
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    A series of Pt-Al2O3 catalysts were investigated by the CS2 poisoning method. For characterizing the nature of active site, a new expression was suggested: the activity frequency was used to relate the strength of active site and the concept of number of multiplet active atoms was introduced for describing the mode of active site forming, based upon which the calculating formulas and the method of measurement were proposed. From the data obtained relating to activity frequency and the number of multiplet active atoms, it has been found that there are two types of active sites on Pt surface, designated asα- and β-site. On a-site the adsorption of CS2 is stronger than on β-site, but for the cyclohexane dehydrogenation, the β-site is more active than a-site. However it is demonstrated whether on a-site or (B)-site the dehydrogenation of cyclohexane are all proceed by the way of dual site mechanism. The role of Sn and Re all can exert influence on the catalytic properties of Pt by both structural and electronic effect.
    The Openning Fraction of Gas Distributor and Back-Mixing of Liquid in Gas Bubble Column
    Mo Zhi-guang Liang Ying-chang Li Lin-que Fan Qiong-jia Chen De-jun Fu Wan-fei Laboratory of Chemical Engineering, South China Institute of Technology
    1979, 30(2):  185-194. 
    Abstract ( 607 )   PDF (528KB) ( 314 )  
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    Performance of gas bubble column has been investigated.It is found that the velocity of the flow of gas through the orifice, uo, must be greater than a critical value, uoc. Pressure drop accross the orifice-plate and surface energy required for bubble formation are estimated. The equations for calculation of critical velocity, uoc and the maximum openning fraction of gas distributor are proposed. Pulse-tracer technique has been used for determination of residence time distribution (RTD) of liquid in bubble column. A non-integer number of tank-in-series model is suggested, and RTD function has been derived. It is shown that RTD function derived fit well the experimental data. Towells equation is recommended to predict the axial dispersion coefficeint of liquid in gas bubble column.
    Study on the Integrated Urea-Ammonia Process by Stripping with Converted Gas at Medium-Pressure
    Shi Shu-Liang Yu Bing-liang Shanghai Research Institute of Chemical Industry
    1979, 30(2):  195-203. 
    Abstract ( 546 )   PDF (501KB) ( 190 )  
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    The integration of urea and ammonia process is a tendency for the development of urea production. In this paper, the development work on integrated urea-ammonia process by stripping with converted gas at medium-pressure is described and this process has been proved in an industrial plant. The result of techno-economic feasibility study has shown it to be viable. A detailed review is also given on the choice of the stripping tower - the critical equipment of the process. Problems encountered are discussed, and the direction of improvement is presented.