CRP－1裂解催化剂工业应用及15万t／a催化裂解装置开工运转

ＣＲＰ－１裂解催化剂首次工业应用和１５万ｔ／ａ催化裂解工业生产装置开工运转结果表明，新研制的ＣＲＰ－１裂解催化剂具有平衡活性高、机械强度好、轻烯烃选择性好、重油转化能力强的特点，是用于Ⅰ型催化裂解的新一代较理想的裂解催化剂。在５４６℃反应温度下，液化气产率可达４２．００ｗ％，丙烯产率可达１８．３２ｗ％；裂解汽油ＭＯＮ８２．３，ＲＯＮ７．６，装置运转正常，虽然反应强度较高及原料较重，但催化裂解装置设备结焦程度与蜡油催化裂化相当，装置能耗７．０６８９ＧＪ／ｔ原料。工业运转取得了较好的生产数据，为今后大型催化裂解装置的建设和生产提供了宝贵的经验。     

Influence of the zeolite structure and acidity on the hydroisomerization of n-heptane

Different acid solids loaded with 1 wt.% of Pt have been studied in n-heptane hydroisomerization in order to determine the influence of porosity and acidity (considered measured by the activity) on selectivities. The open solids like Y and β zeolites and a pillared clay present different activities towards n-C₇ conversion but similar selectivities. Consequently, acidity seems to be a less important parameter in n-C₇ isomerization than porosity. Very different results were obtained as a function of the solid structure and so n-heptane hydroconversion appears to be a simple and rapid method to obtain data concerning the porosity of unknown zeolite structures. The highest content of multibranched isomers was obtained on open solids but the value predicted by the thermodynamic was never reached due to the fact that cracking of multibranched isomers is initiated quickly.     

Structural Steel ASTM A709—Behavior at Uniaxial Tests Conducted at Lowered and Elevated Temperatures, Short-Time Creep Response, and Fracture Toughness Calculation

This paper presents the temperature dependence of the mechanical properties of structural high-strength low-alloy (HSLA) ASTM A709 Gr50 steel (En10025: S355 JO; DIN: ST 52-3U). Engineering stress-strain diagrams at lowered and elevated temperatures are presented. Creep responses for selected constant stresses at selected temperatures are also presented and are fit with a rheological model. Additionally, a relation between impact toughness and fracture toughness is proposed and is validated using results from notch impact tests on a Charpy pendulum impact machine.     

纤维增强树脂传递模塑制品裂纹问题探讨

本文主要讨论了纤维增强树脂传递模塑制品产生裂纹的原因及解决问题的有效途径。通过对绝缘座成型工艺技术的研究,用生产实例说明了解决问题的过程     

Mechanism behind the Size Effect Phenomenon

Size effect (SE) on quasi-brittle fracture of concrete and concretelike heterogeneous materials has been commonly demonstrated by the influence of specimen size D on the transition from strength-dominant fracture to toughness-dominant fracture for geometrically similar specimens with a common initial-crack/specimen-size ratio, i.e., a0/D = constant. Under such a condition, size D appears to be the single controlling parameter for SE. In this study, we clarify that the primary source of quasi-brittle fracture, the presence of a large fracture process zone (FPZ) in front of a crack-tip, does not follow the condition of geometry similarity even for geometrically similar specimens. This suggests that the role of FPZ is not clearly explained for SE. Therefore, this study emphasizes the interaction between FPZ and the nearest specimen/structure boundary, and the consequent SE phenomenon. The deficiencies associated with the common SE models developed by Bazant and his coworkers are discussed through comparisons with the analysis on the boundary and FPZ interaction, or the boundary effect. It is shown that quasi-brittle fracture and the transition from strength-dominant fracture to toughness-dominant fracture can occur even if specimen/structure size D is constant, i.e., size D is not the dominant factor for SE.     

Synergetic effects of Y-zeolite and amorphous silica-alumina as main FCC catalyst components on triisopropylbenzene cracking and coke formation

The synergetic effects of HY-zeolite and silica-alumina (SA), as two major components of an FCC catalyst, on the cracking activity and coking tendency during catalytic cracking of 1,3,5-triisopropylbenzene (TiPB, as a resid representative) were studied. NaY-zeolite and SA were synthesized by hydrothermal and co-precipitation methods, respectively, and ammonium exchanged for three times at 80 °C. The catalysts were characterized by XRD, XRF, SEM, BET, AAS and ammonia TPD techniques. TiPB cracking was investigated on four different catalyst configurations including SA, Y-zeolite, SA.Y and SA-Y in a fixed bed reactor. SA.Y stands for physical mixture of equal amounts of Y-zeolite and SA. For SA-Y, a bed of SA was placed upstream of the same amount of Y-zeolite. The catalysts were in-situ activated at 475 °C and evaluated by TiPB cracking at 350 °C. The coke content of the catalyst beds, after 40 min cracking of TiPB, was estimated by TPO using an FT-IR gas cell. At 3 min time on stream, 5.2 times higher yield of benzene, as a deep cracking product, is observed on SA-Y as compared to SA.Y. The TiPB conversion decreases in the order of SA-Y > SA.Y > Y-zeolite ? SA. Furthermore, as compared to Y-zeolite, 24% lower coke is formed on SA-Y. Also CO evolution during TPO of coked SA-Y catalyst is about 24% lower than that of the coked zeolite. As a result, protecting of Y-zeolite by SA from direct exposure to resid feed enhances the cracking activity, decreases the tendency to coke formation and diminishes CO emission in the catalyst regeneration process.     

Effect of Fiber-Reinforced Polymer Wraps on Corrosion Activity and Concrete Cracking in Chloride-Contaminated Concrete Cylinders

This paper presents the results of an experimental study designed to investigate the effect of fiber-reinforced polymer (FRP) wraps on corrosion activity and concrete cracking in chloride-contaminated concrete cylinders. Thirty-five concrete cylinders, each having 102?mm diameter and 204?mm height, concentrically reinforced with one steel reinforcing bar, were subjected to accelerated corrosion exposure for 80?days. Test parameters included level of applied potential, presence of FRP wraps, and bar diameter. The corresponding current and concrete expansion were continuously monitored throughout the corrosion exposure. At the end of the test, the steel bars were extracted, cleaned of rust, and weighed to determine the actual steel mass loss. The results showed that, for the same applied fixed potential, FRP wraps effectively reduced the corresponding current, the concrete expansion, and the steel mass loss. For the same applied potential, the current density increased as the bar diameter decreased. For the same corrosion depth, the circumferential expansion of the cylinder caused by corrosion decreased as the concrete cover-to-bar diameter ratio (c/d) increased.     

Porothermoelastic Analysis of the Response of a Stationary Crack Using the Displacement Discontinuity Method

Thermally induced volumetric changes in rock result in pore pressure variations, and lead to a coupling between the thermal and poromechanical processes. This paper examines the response of a fracture in porothermoelastic rock when subjected to stress, pore pressure, and temperature perturbations. The contribution of each mechanism to the temporal variation of fracture opening is studied to elucidate its effect. This is achieved by development and use of a transient displacement discontinuity (DD) boundary element method for porothermoelasticity. While the full range of the crack opening due to the applied loads is investigated with the porothermoelastic DD, the asymptotic crack opening is ascertained analytically. Good agreement is observed between the numerical and analytical calculations. The results of the study show that, as expected, an applied stress causes the fracture to open while a pore pressure loading reduces the fracture width (aperture). In contrast to the pore pressure effect, cooling of the crack surfaces increases the fracture aperture. It is found that the impact of cooling can be more significant when compared to that of hydraulic loading (i.e., an applied stress and pore pressure) and can cause significant permeability enhancement, particularly for injection/extraction operations that are carried out over a long period of time in geothermal reservoirs.     

泰国0.7Mt/a催化裂解装置的设计和投产

泰国石化工业公司采用中国石化石油化工科学研究院开发的催化裂解技术,建成１套０．７ Ｍｔ／ａ催化裂解装置,主要用于生产丙烯。该装置于１９９７年５月建成投产,原料为经低苛刻度加氢处理的沙特阿拉伯轻质原油的直馏粗柴油,采用该院专门开发的ＣＲＰ－Ｓ催化剂,在补充速率较低的情况下,催化剂有较好的丙烯和汽油选择性。丙烯产率超过１７％,汽油产率为３１．９％,研究法辛烷值为９９．３,马达法辛烷值为８５．３。同时该院的中试结果还准确地预测了装置性能并提供了设计基础数据。     

On the mechanical behaviour under cyclic loading of ceramic matrix composites

In this paper, a constitutive law is presented to model the mechanical behaviour of ceramic matrix composites. It allows matrix-cracking, interfacial debonding, sliding and wear to be accounted for in the framework of continuum mechanics. Based upon micromechanical studies, a 1D and 2D model was derived. An application was performed on a [0,90] SiC/SiC composite.