A PROCEDURE FOR EVALUATION OF COMMERCIAL FCC CATALYSTS

Based on the correlations between laboratory units and commercial plants, a procedure has been developed to guide commercial FCC (Fluid Catalytic Cracking) catalysts selection. Examining the operability of catalyst mixtures during catalyst transition period is emphasized. The testing procedure is simple and reliable. A commercially available catalyst and the catalyst currently in use have been compared to demonstrate the applicability of this procedure. The commercial testing has confirmed the reliability of laboratory results. The use of the catalyst evaluated led to a 30% saving in catalyst cost.     

Coking kinetics of a Cr2O3/Al2O3 catalyst during 1-butene dehydrogenation: Effect of H2 partial pressure

The influence has been studied of the partial pressure of hydrogen (0–30 kPa) upon the coking rate of a Cr₂O₃/Al₂O₃ commercial catalyst during 1-butene dehydrogenation. Coke deposition has been analysed using a monolayer-multilayer reversible coke growth model (MMRC model). This model provides good fits to the experimental data, within the range of partial pressure of H₂ studied, and allows us to estimate the main kinetic parameters involved in the coking-deactivation process. The results obtained reveal a dual effect of hydrogen: competition against 1-butene for the active sites and the removal of coke precursors from the catalyst surface. Bom effects diminish the coking rate as the H₂ partial pressure is increased.     

Three-dimensional modelling of Non-Newtonian fluid flow in a coat-hanger die

The three-dimensional model of isothermal flow of power-law fluid in a coat-hanger die has been developed using finite element method. The shape of coat-hanger die used in the present model was determined according to the previous analytical design equation which is based on one-dimensional flow model in the manifold and the slot. Because uniform flow rate across the die outlet is most important to achieve uniform thickness of extruded polymer sheet or film, flow rate distribution is mainly examined to determine the valid process condition for the design equation as the design parameters are changed. The effects of fluid property in terms of power-law index and process parameters not considered in one-dimensional design equation such as die inlet size and the presence of land were analyzed. Results show that the manifold angle is the most influencing design parameter on flow rate distribution. When the material of different power-law index from design value is processed, the change of power-law index affects the uniformity of flow rate appreciably.     

焦化装置掺炼催化裂化油浆技术经济分析

通过油浆掺炼小试, 对以加工管输原油等中间基原油为主的安庆炼厂焦化装置掺炼RFCC油浆生产中的物料平衡、产品质量、生产操作、经济效益等方面进行了分析，阐述油浆掺炼将导致焦化装置液收下降、气体及焦炭产率上升，蜡油芳烃含量上升，不利于提高装置加工量及经济效益的提高     

国内外型焦生产工艺及发展前景

介绍了国内外型焦技术的生产工艺、型煤碳化的过程和影响因素,以及国内目前几种碳化窑炉,通过对型焦和焦炭的对比分析,指出洁净型焦生产技术的优势必然会使它在未来具有巨大的发展空间。     

Shear rates investigation in a scraped surface heat exchanger

The electrodiffusion technique was performed in order to investigate the shear rate on a scraped surface heat exchanger. Microelectrodes were placed inside: the walls of the outer cylinder; the inlet and outlet bowls; the rotor and the blades. Highly viscous Newtonian fluid (Emkarox HV45 solutions) and non-Newtonian model fluid (aqueous solutions of CMC) were used. The electrodiffusion method allowed us to measure wall shear rates. Maximum shear rate was observed at the scraping surface and caused by blades scraping, high shear rate was also measured on the leading edge of the blades. In the other parts of the exchanger, shear rate remained low but the development of Taylor vortices completely modified the scraped surface heat exchangers behaviour inside the surface of the bowls. A dimensionless representation of the friction factor was established for the inner and outer wall surface of the exchanger.     

中国无烟煤用于炼焦配煤

在系统地研究了中国优质无烟煤分布和无烟煤在炼焦配煤中可行性的基础上，认为在炼焦配煤中配入5％左右的无烟煤，不仅可以降低炼焦生产成本，且还可降低焦炭的灰分和硫分，提高焦炭质量。     

DAMPED OSCILLATIONS IN A BINGHAM PLASTIC FLUID

Stokes' second problem, the propagation and damping of waves into a semi-infinite fluid generated by harmonic oscillations of a flat pate on the surface, is solved for the simple Bingham Theological constitutive model. The solution reveals the existence of “windows” in the distance-time-stress space in which shearing is possible whereas outside these restricted regions no shearing can occur. Within these restricted regions the wave forms developed are exponentially damped, traveling waves which propagate from the excitation plane into the fluid and disappear along definitely prescribed boundaries determined by the yield condition. The most significant consequence of the existence of these “windows” of shear is that even very small yield stresses will radically modify the induced velocity wave patterns from that which would be expected based upon the classical Newtonian fluid solution of Stokes' second problem. At least in this physical setting, it is not necessary for shear to occur globally for motion to occur anywhere, as has been postulated in some recent studies of complex motions. Thus, the motion is consistent with a simple Bingham model which does possess a yield stress.     

覆炭载体及镍覆炭催化剂的积炭行为研究

用恒温热重法，以正己烷脱氢反应为指示反应，研究了γ-Al2O3覆炭载体（CCA0，γ-Al2O3，Ni/Al2O3及Ni/CCA催化剂的抗结焦性能；考察了覆炭原料，覆炭量对CCA的抗结焦性能的影响及积炭温度，正己烷浓度和覆炭量对Ni/CCA催化剂的抗结焦性能的影响。结果，CCA，Ni/CCA催化剂的抗结焦性能优于γ-Al2O3，Ni/Al2O3，以环烷烃为覆炭原料得到的CCA的抗结焦性能最好。     

连续移动床炼焦新工艺

本文论述了目前国内外连续移动床炼焦新技术的工艺原理，介绍了国外连续移动床炼焦新技术的工艺流程及特性，并对连续移动床炼焦新技术的经济技术指标和焦炭特性进行了评述。