C5/C6烷烃异构化Pt/Al2O3-Cl催化剂的性能

采用浸渍法制备了Pt/Al₂O₃,在300℃、CCl₄氯化1h,制备出Pt/Al₂O₃-Cl催化剂。采用FT-IR、XRD、TEM、CO-IR、Py-IR和TPD等方法表征了催化剂,并与中温型RISO催化剂的催化性能进行比较。结果表明,在氯化处理过程中氯取代了氧化铝的表面羟基,导致3000～3800cm^-1红外吸收峰强度大幅度减小,但催化剂的晶相不发生改变;氯化使Pt粒子的平均粒径增大,粒径分布变宽,金属分散度降低;氯化后金属Pt主要以+2价的PtCl₂的形式出现,其中一部分生成了易升华的PtCl₂·2AlCl₃,从而导致Pt含量降低;氯化后的催化剂上只有L酸,评价后既有L酸,又有B酸;氯化后的催化剂热稳定不高,随着温度升高,3种类型的氯化物相继脱出;Pt/Al₂O₃-Cl相对于中温型RISO催化剂表现出较好的异构化性能,正己烷转化率达88.17%,2,2-二甲基丁烷选择性达29.68%,裂化和氢解几乎没有发生。     

Hydrogenation of CO2 over Fe-K based catalysts in a fixed bed reactors at elevated pressure

Catalytic hydrogenation of CO₂to produce hydrocarbons was conducted in a fixed bed reactor (1.6 cm-IDx60 cm-High). Fe-K based catalysts (KRICAT-A, B) were used for more than 850 hours to maintain CO₂ conversion level up to 30 C-mol% in the fixed bed micro-reactor. Effects of operating variables on the CO₂ conversion, hydrocarbon yield and its selectivity were investigated. The CO₂ conversion and total hydrocarbon yield increased with increasing reaction temperature (250-325 °C), pressure (0.5-2.5 MPa) and H₂/CO₂ mol ratio (2-5); however, they decreased with increasing space velocity (1,000-4,000 ml/g_cathr) in the reactor. The selectivities of liquid products increased with increasing reaction pressure; however, they decreased with increasing temperature, space velocity and H₂/CO₂ ratio. From the results of an experimental study, optimum operating conditions for the maximum yield of olefinic liquid products were found as T=315 °C, P=1.5 MPa, SV=2,000 ml/g_cathr and H₂/CO₂ ratio=3 in the fixed bed reactor within these experimental conditions. Presented at the Int’l Symp. on Chem. Eng. (Cheju, Feb. 8-10, 2001), dedicated to Prof. H. S. Chun on the occasion of his retirement from Korea University.     

Synthesis of MFI-type zeolites under atmospheric pressure

Silicalite and highly silicious ZSM-5 were synthesized using two reaction mixtures with different crystal growth environments, a dispersed low density mixture and a separated high density mixture, at 93 ±3 ‡C under the atmospheric pressure. Nucleation behavior and the transformation process of two mixtures were investigated utilizing various analytical techniques such as XRD, FT-IR, TGA, SEM, and pH measurement. During the induction period, the same intermediate phase was observed in both mixtures. The presence of this phase was found to be dependent on the degree of dilution of the reaction mixture. After the induction period, a sharp increase in both the degree of crystallization and the pH of the reaction mixture was detected. This indicates that the pH change in the reaction mixture is closely related to the crystallization process. From these observations, a crystallization mechanism is proposed on the basis of the appearance of stable silicate species and the role of OH^- ions during the induction period. According to this mechanism, MFI-type zeolite grows by condensation reaction among the stable silicate species formed during the induction period.     

Electrochemical synthesis of ba- and Sr-based titanate thin films using Ti electrode prepared by RF sputtering

Barium and strontium titanate films were electrochemically synthesized onto Ti thin film prepared by RF sputtering. Applied current waveform was modulated to investigate the film growth mechanism. Superimposed cathodic pulses accelerated the formation of titanate thin films, and both the electrode surface pH and (Ba²⁺, Sr²⁺) ion size had a strong influence on film formation. Titanate film formation mechanism was investigated with a scanning electron microscope, an X-ray diffractometer and an electrochemical quartz crystal microbalance (EQCM).Insitu mass change of Ti electrode during electrolysis indicated that electrochemical method sets a limit to film growth.     

Characteristics of carbon dioxide hydrogenation in a fluidized bed reactor

Characteristics of CO₂ hydrogenation were investigated in a fluidized bed reactor (0.052 m IDxl.5 m in height). Coprecipitated Fe-Cu-K-Al catalyst (d_ρ=75–90 Μm) was used as a fluidized solid phase. It was found that the CO₂ conversion decreases but the CO selectivity increases, whereas the space-time-yield attains maximum values with increasing gas velocity. The CO₂ conversion has increased, but CO selectivity has decreased with increasing hydrogenation temperature, pressure or H₂/CO₂ ratio in the fluidized bed reactor. Also, the CO, conversion and olefin selectivity appeared to be higher in the fluidized bed reactor than those of the fixed bed reactor. Presented at the Int’l Symp. on Chem. Eng. (Cheju, Feb. 8–10, 2001), dedicated to Prof. H. S. Chun on the occasion of his retirement from Korea University     

Photopolymerization of hyperbranched aliphatic acrylated poly(amide ester). I. Synthesis and properties

The hyperbranched aliphatic poly(amide ester) (HAPAE) was synthesized based on 4‐N,N‐di(2‐hydroxy ethyl)‐4‐ketobutyric acid prepared by the reaction of succinic anhydride with diethanol amine, as an AB₂ monomer (repeating unit), and with 2‐ethyl‐2‐(hydroxymethyl)‐1,3‐propanediol, as a core molecule, using acid catalysis. The second generation of the product was characterized by measuring dynamic viscosity, which decreased sharply with the increase in frequency. The product exhibits relative thermal stability as analyzed by thermogravimetry in a nitrogen atmosphere. The glass transition temperature, determined by differential scanning calorimetry, is ?27 °C. The molar mass was measured by vapor pressure osmometry. The polydispersity, measured by size exclusion chromatography, is 2.16. Dynamic mechanical thermal analyses were performed to characterize the thermal properties of the ultraviolet‐cured films of the acrylate‐modified HAPAE. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1630–1636, 2001     

棒形喷淋器的设计及应用

随着化学清洗范围的不断扩大，喷淋清洗技术在各类贮罐的清洗中得到了大量应用。针对一次圆顶贮罐的清洗，设计出了一种棒形喷淋器并取得满意的效果     

电沉积触媒的制备及其合成金刚石的研究

用电沉积的方法以Ni70Mn25Co5为基材制备了合成金刚石的触媒，选择适当的合成条件，在国产六面顶压机上用此电沉积触媒合成出颜色和晶型都较好的金刚石，为纯铁片做为基材制备电沉积触媒，降低合成金刚石触媒生产成本奠定了一定基础。     

Graphene oxide membranes supported on the ceramic hollow fibre for efficient H2 recovery

The special channels and intrinsic defects within GO laminates make it a very potential candidate for gas separation in recent years. Herein, the gas separation performance of GO membranes prepared on the surface of ceramicα-Al_2O_3 hollow fibre was investigated systematically. The microstructures of ceramic hollow fibre supported GO membranes were optimized by adjusting operation conditions. And, the GO membrane fabricated at 30 min exhibited great promising H_2 recovery ability from H_2/CO_2 mixture. At room temperature, the H_2 permeance was over 1.00 × 10~(-7)mol·m~(-2)·s~(-1)·Pa~(-1)for both single gas and binary mixture. The corresponding ideal selectivity and mixture separation factor reached around 15 and 10, respectively. In addition, humility, operation temperature, H_2 concentration in the feed and the reproducibility were also studied in this work.     

A systematic strategy for multi-period heat exchanger network retrofit under multiple practical restrictions

A systematic strategy for retrofit of the multi-period heat exchanger network (HEN) on the basis of the multi-objective optimization is developed. In this three-stage procedure, a simplified multi-objective optimization model of the multi-period HEN is first established and then solved to target the retrofit, aiming to minimizing the total annual cost and total annual CO2 emissions. The obtained Pareto front represents series of retrofit targets under different emission limitations, from which the most desirable one can be selected. The matching of the existing and the required heat exchangers is further implemented to finalize the retrofit, which wil meet the practical retrofit requirements and matching restrictions. The application of the proposed procedure is il ustrated through a case study of a HEN in a vacuum gas oil hydro-treating unit.