The role of surfactant structure and monoethanolamine in the environmental stress cracking of polycarbonate

The critical strains required to initiate cracking of polycarbonate exposed to a number of poly(oxyethylene)ethoxylate surfactants were determined. Solubility parameters of the surfactants were calculated from knowledge of the molecular structure. A model proposed by Jacques and Wyzgoski that uses the square of the solubility parameter difference of the surfactant and polycarbonate and the surfactant molar volume was determined to be useful for predicting critical strains for polycarbonate. A major assumption in this model is that stress cracking is related to swelling or plasticization of the polymer by the cracking agent, which ultimately leads to the polymer's failure. However, the model does not predict the observed strong stress cracking of polycarbonate by monoethanolamine. In this investigation it was determined that polycarbonate is chemically degraded by monoethanolamine. This degradation is sufficient to initiate stress cracking at lower strains than would otherwise be predicted by solubility parameter and molar volume concepts. With the knowledge obtained from this investigation, it is possible to predict which poly(oxyethylene)ethoxylate surfactants are stress cracking agents for polycarbonate.     

CGP-C催化剂提高汽油辛烷值的工业应用

加工大庆类原料的催化裂化装置产品收率中汽油辛烷值普遍较低,中国石油吉林分公司炼油厂三催化装置加工原料为大庆常渣,催化装置通过MIP改造,催化稳定汽油辛烷值提高至约91.5,使用新配方CGP-C催化剂,稳定汽油辛烷值又提高1.6个单位,装置年增加经济效益超过9 000万元。     

Differential thermal analysis of premix polymer cement materials

In this paper, the use of DTA thermograms, to examine the interaction between premix polymer systems and hydrating cement, are described. The thermograms indicate that the polymerisation method (i.e., thermal or irradiation) has little effect on the nature of the hydration products. It was also observed that polystyrene, polyvinyl acetate, polymethyl methacrylate and polyester-styrene, as premix components, react with the hydrating cement. Polystyrene and polyisoprene have no effect on the calcium hydroxide endotherm while polyacrylonitrile and polymethyl methacrylate have a slight effect. Polyvinyl acetate and polyester-styrene markedly reduce the calcium hydroxide endotherm and reduce the maturity of the paste.     

烃重组汽油与催化重整汽油的PONA分析及其组成对比

烃重组技术和催化重整技术都可以生产高辛烷值汽油调和组分,采用气相色谱PONA分析法对烃重组汽油和催化重整汽油分别进行组成分析,并对数据结果进行对比讨论;PONA分析显示,虽然二者都是芳烃质量分数大于70％的高芳烃含量汽油,但在组成分布上存在明显不同;通过结果判断,烃重组汽油的芳烃集中在C8～C10范围,重整汽油中的芳烃...     

中红外光谱法测定汽油中含氧化物含量

利用IROX2000傅里叶红外光谱仪测定汽油中的含氧化物（醇类和醚类）,选用直馏汽油、重整汽油、催化裂化汽油等基础汽油配制36组不同浓度、不同含氧化物组分的标准样品,对成品汽油和配制的含氧汽油中的氧含量进行测定,并与气相色谱方法对比,验证了中红外光谱法测定汽油中含氧化物含量的可靠性.实验证明,中红外光谱法具有分析快速、重复性好、分析成本低等优点.     

汽油催化改质反应过程数值模拟

在汽油催化反应动力学模型和气固两相流动模型的基础上,建立了汽油改质反应过程流动-反应耦合模型。针对不同的转化反应器构型（提升管、提升管-床层反应器）,对汽油改质过程进行了数值模拟。模拟结果表明,对提升管反应器而言,汽油经过低温改质反应后,烯烃含量可以从35.1%降低到18%左右,烯烃降低幅度可达48%,汽油中烯烃主要转化为异构烷烃。另外,随着反应温度的升高,汽油转化反应中的裂化反应增强,导致汽油收率下降。对于提升管-床层反应器而言,汽油中的烯烃含量可以降得更低,在床层空速4时,烯烃含量可以降低到5%左右,汽油收率为80%左右。     

降低汽油烯烃含量MIP工艺的工业应用

介绍了降低汽油烯烃含量MIP工艺在永坪炼油厂50万t/a催化裂化装置的工业应用情况。MIP工艺应用后,加工量提高5~8 t/h,总液收提高0.20%~0.32%,汽油收率约上升2%,柴油收率下降1.0%~1.5%,汽油烯烃体积分数降至30%以下,汽油的研究法辛烷值(RON)提高至接近90。运行结果表明,该工艺具有明显降低汽油烯烃含量的效果。     

催化裂化汽油催化氧化及萃取脱硫的研究

以分子氧为氧化剂,将催化氧化与萃取分离相结合,开展催化汽油氧化萃取脱硫研究。结果表明,与直接萃取相比,汽油经过氧化及溶剂萃取,汽油脱硫率有所提高,并且随着氧化温度的提高而增大,氧化过程对催化汽油脱硫有贡献。催化剂能够加速硫化物氧化反应,几种催化剂的汽油脱硫率从大到小顺序为：氧化铈＞碳酸锰或四硼酸钠或氧化锌＞硼酸或过硼酸钠。使用氧化锌或碳酸锰催化剂时,随着催化剂用量的增加,汽油脱硫率总体呈现降低的变化趋势。以硼酸为催化剂时,脱硫率随着催化剂用量的增加先增加后降低,认为催化汽油中硫化物的氧化反应符合连串反应机制。     

Synthesis and characterization of interpenetrating networks from polycarbonate and cellulose acetate butyrate

Polycarbonates (PC) are currently used for organic optical glass; nevertheless they show a poor impact resistance which may be increased by combination with cellulose acetate butyrate (CAB) into a PC/CAB interpenetrating polymer network (IPN), without altering the material transparency as we show here. A series of rigid IPNs based on an aliphatic polycarbonate and CAB was prepared through in situ polymerization techniques. The kinetics of the formation of two networks in the IPNs were studied by FTIR spectroscopy. Effects of the CAB cross-linking and weight proportions of the two components in the IPNs were investigated by dynamic mechanical thermal analysis.     

催化汽油过氧乙酸氧化及溶剂萃取脱硫

以钨酸钠为氧化催化剂,开展过氧乙酸氧化及溶剂萃取催化汽油脱硫实验研究。研究结果表明,随着氧化溶液中钨酸钠质量分数的升高,脱硫率先升高后趋于不变,汽油收率略降。溶剂萃取对催化汽油脱硫也有贡献,3种溶剂脱硫率为聚乙二醇-400＞三甘醇＞二甘醇,而汽油收率的顺序相反,聚乙二醇-400是汽油脱硫的较好萃取溶剂。随着氧化温度升高或氧化溶液用量增大,脱硫率增大,汽油收率减少。随着氧化时间延长,脱硫率先增大后降低,而汽油收率降低。较佳的氧化温度为70 ℃,氧化时间10 min。萃取时间和萃取温度对脱硫率影响不大,适当降低萃取温度有利于提高汽油收率。     

A novel conceptional process for residue catalytic cracking and gasoline reformation dual-reactions mutual control

Based on the subsidiary riser FCC (SRFCC) process for gasoline reformation [Y.H. Bai, J.S. Gao, S.C. Li, C.M. Xu, Petrol. Process. Petrochem. (China) 35 (2004) 17–21, J.S. Gao, C.M. Xu, Y. Mao, et al., Petrol. Refin. Eng. (China) 35 (2005) 7–9], a novel conceptional process for residue catalytic cracking and gasoline reformation dual-reactions mutual control (DMC) was proposed and relevant experimental researches were carried out in a Technical Pilot Scale Riser (TPSR) FCC apparatus. The goals of DMC were to improve product quality and increase desirable product yield in residue catalytic cracking as well as in FCC gasoline upgrading. The experiments showed that the decrease of temperature difference between feedstock and regenerated catalysts in DMC by directly leading the cooled regenerated catalysts into riser reactor or feeding gasoline into riser reactor in vapor phase could decrease the amount of dry gas and coke and obtain a better quality of upgraded gasoline. Moreover, the spent catalysts still retaining high level of activity could be recycled to the base of the main riser reactor treating heavy oil and mixed with regenerated catalysts in DMC, it allows residue catalytic cracking to operate at high catalyst-to-oil ratio and the relatively low inlet catalysts temperature. The experimental results also showed that the mixed catalysts could improve the product selectivity in residue catalytic cracking, especially for light oil (gasoline and diesel). In addition, compared with the routine RFCC, the product distribution from the residue catalytic cracking in DMC contains more liquid products, less dry gas, and a better gasoline quality.     

Vinyl Polymerization. 218. Polymerization of Methyl Methacrylate in the Presence of Nylon-6 Fiber and Water

The polymerization of methyl methacrylate in the presence of nylon-6 fibers and water was carried out. It was found that the conversion in the absence of water was the same as that of thermal polymerization, but in the presence of water the conversion was much higher. When methyl methacrylate and water existed sufficiently in the polymerization system, the rate of polymerization (R_p) was given by the following equation; R_p = k (Nylon)^1,0 (Methyl methacrylate)⁰ (Water)⁰. The over-all activation energy of the polymerization was found to be 13 kcal/mole. The polymerization of styrene, acrylonitrile, vinyl acetate, and methyl acrylate could not be initiated by the system of nylon and water. Apparent grafting efficiency of polymethyl methacrylate onto nylon was calculated from the amount of polymer which was not extracted with acetone. The efficiency was independent on the reaction time and the amount of water, and increased with the amount of nylon, while it decreased with the amount of methyl methacrylate and with reaction temperature. From the fact that a major part of the polymethyl methacrylate could not be extracted, it was concluded that the polymerization of methyl methacrylate in the presence of nylon and water occured predominantly inside the fiber. The degree of the polymerization of polymethyl methacrylate formed inside the nylon fiber was considerably higher than that of homopolymethyl methacrylate formed outside the fiber. It was qualitatively recognized that the major part of the polymethyl methacrylate generated in the fiber was not grafted onto nylon, but existed as homopolymer.     

Investigation of the components in RFCC gasoline affecting the accuracy of potentiometric titration by GC-MS and GC-IR

This paper described that there were two or more endpoints in the curve when potentiometeric titration was used to determine the contents of mercaptan sulfur in residue fluidized catalytic cracking (RFCC) gasoline. Comparing with the one endpoint of a mixture solution of C₂–SH to C₁₀–SH determined under the same conditions, we found some components in RFCC gasoline affected the result of titration. A facile method washing the gasoline with 2 wt.% HCl solution was brought out to eliminate the interfering components from the RFCC gasoline. After being treated with this method, all RFCC gasoline that contained 14–27 μg/ml mercaptan sulfur (S_RSH) met the quality specification (S_RSH shall not exceed 10 μg/ml) [GB 17930-1999, Chinese national standard for unleaded petrol (gasoline) for motor vehicles]. The analysis of gas chromatography-mass spectrometry (GC-MS) and gas chromatography-infrared spectrometer (GC-IR) verified that the interfering components were aniline, phenol and their alkyl-substituted derivatives.     

二段多产丙烯试验轻汽油转化不充分的原因

在重油二段提升管催化裂解多产丙烯(TMP)技术中,回炼富含烯烃的轻汽油可进一步增产丙烯。实验室研究表明,回炼占新鲜原料19%的轻汽油,丙烯收率即可增加5%以上,而干气增加不到1%。而在工业试验中回炼占新鲜原料21.88%的轻汽油对丙烯和干气的贡献分别为1.51%和1.37%。其原因在于回炼的轻汽油高速喷入本身造成的催化剂稀相区和重油进料造成的催化剂稀相区,导致以分子形式分散的轻汽油与催化剂不能充分接触、吸附和发生催化转化,并因催化剂流化密度低而不能及时终止未能吸附的轻汽油分子发生热裂化反应,因而丙烯的贡献低而对干气的贡献高。     

Extractive desulfurisation of gasoline with tetrabutyl ammonium chloride-based deep eutectic solvents

In this study, three tetrabutyl ammonium chloride (TBAC)-based deep eutectic solvents (DESs) were synthesised and used for desulfurising model and real gasolines. Extraction efficiencies of different DESs followed the order of TBAC/ethylene glycol > TBAC/glycerol > TBAC/malonic acid. After five extraction cycles, the extraction efficiencies of TBAC/ethylene glycol, TBAC/glycerol and TBAC/malonic acid reached 99.5, 99.3 and 99.2%, respectively. Additionally, the structures of original and recycled DESs were analysed and the results showed that DESs maintained their original structures after regeneration. Finally, the desulfurisation performance of DESs for real gasoline was also investigated. This work will provide new green extractants for gasoline desulfurisation.     

Anisotropic aspects of the environmental stress cracking of acrylonitrile-butadiene-styrene and styrene acrylonitrile copolymers in methanol

Critical strains causing environmental stress cracking of injection-molded poly(acrylonitrile-butadiene-styrene) (ABS) and poly(styrene-acrylonitrile) (SAN) plaques were determined upon exposure to methanol. Measurements were obtained for samples strained either parallel or perpendicular to the melt flow direction and for samples located at various distances from the mold gate. Critical strains were significantly higher in the direction parallel to the melt flow compared to the transverse direction. The degree of anisotropy increased with increasing rubber content. For ABS containing 46 percent rubber, the critical strain at one point was determined to be 2.99 percent in the direction of melt flow, but only 0.47 percent in the orthogonal direction. For this material, critical strains determined parallel to the melt flow decreased with distance from the gate; whereas, critical strains for SAN and ABS containing 30 percent rubber remained essentially constant. Orientation of the plaques was assessed using shrinkage determinations and a thermal conductivity technique. Though a straightforward correlation of orientation with critical strain is observed for ABS, a similar relationship is not observed for SAN. These results suggest that although stress cracking occurs in the glassy matrix of ABS, it is the dispersed rubbery phase which controls the magnitude of strain required to initiate cracking.     

A novel MINLP-based representation of the original complex model for predicting gasoline emissions

The Environmental Protection Agency (EPA) introduced Reformulated Gasoline (RFG) requirements as a measure to reduce emissions from gasoline-powered vehicles in certain geographic areas. As part of this effort, the EPA developed empirical models for predicting emissions as a function of gasoline properties and established statutory baseline emissions from a representative set of gasolines. All reformulated gasoline requires certification via this model, known as the Complex Model, and all refiners and importers calculate emissions performance reductions from the statutory baseline gasoline. The current representation of the Complex Model is extremely difficult to implement within refinery operations models or to use in combination with models for designer gasoline. RFG and boutique fuels are key driving forces in the North American refining industry.The RFG models introduce increasingly complex constraints with the major limitation that they are implicitly defined through a series of complicated disjunctions assembled by the EPA in the form of spreadsheets. This implicit and cumbersome representation of the emissions predictive models renders rigorous optimization and sensitivity analysis very difficult to address directly. In this paper, we discuss how the federal government requirements for reformulated gasoline can be restated as a set of mixed-integer nonlinear programming (MINLP) constraints with the aid of disjunctive programming techniques. We illustrate the use of this model with two simple example fuel blending problems.     

催化裂化汽油脱硫技术进展

随着环保法规的日益严格,对汽油的质量要求越来越高,全世界都在为降低汽油硫含量而不懈努力。降低汽油硫含量是改善空气质量的有效手段。脱硫技术已经成为各炼油企业的关键技术。汽油中的硫化合物主要来自FCC(流化催化裂化)汽油,因此FCC汽油脱硫技术的研究与开发具有重要意义。目前,减少FCC汽油硫含量的技术主要有：FCC原料油加氢脱硫、FCC汽油加氢脱硫、溶剂萃取脱硫、催化裂化脱硫、氧化脱硫、生物脱硫和吸附脱硫等。笔者综述了国内外FCC汽油脱硫技术进展。     

催化裂化汽油加氢脱硫技术的研究

在分析催化裂化汽油硫和烯烃分布不均匀的基础上,对全馏分催化裂化汽油选择性预加氢后再分馏,开发出活性高和稳定性好的催化裂化汽油加氢脱硫催化剂及工艺技术。结果表明,产品汽油硫含量由196.2×10^-6降至39.2×10^-6,加氢脱硫率80.1%,硫醇由33.8×10^-6降至5.95×10^-6,烯烃体积分数较原料油降低了2.1个百分点, 研究法辛烷值损失0.5个单位,收率99.24%,可生产满足国Ⅳ清洁标准的汽油调和组分。     

Study on reformulation of fluid catalytic cracking gasoline and increasing production of light olefins

The effects of reaction temperature, mass ratio of catalyst to oil, space velocity, and mass ratio of water to oil on the product distribution, the yields of light olefins (light olefins including ethylene, propylene and butylene) and the composition of the fluid catalytic cracking (FCC) gasoline upgraded over the self-made catalyst GL in a confined fluidized bed reactor were investigated. The experimental results showed that FCC gasoline was obviously reformulated under appropriate reaction conditions. The olefins (olefins with C atom number above 4) content of FCC gasoline was markedly reduced, and the aromatics content and octane number were increased. The upgraded gasoline met the new standard of gasoline, and meanwhile, higher yields of light olefins were obtained. Furthermore, higher reaction temperature, higher mass ratio of catalyst to oil, higher mass ratio of water to oil, and lower space velocity were found to be beneficial to FCC gasoline reformulation and light olefins production.