碳铵液解吸塔的模拟计算

利用模拟软件对碳铵液解吸塔系统进行了模拟计算，分析了影响解吸塔操作的主要因素：理论板数，进料位置及温度，回流液温度和蒸汽用量等，并确定了解吸塔的最佳工艺条件。     

原油蒸馏过程的模拟与分析

采用ASPENPLUS软件的PetroFRAC模块对原油蒸馏过程进行模拟,模拟得到的总物料平衡、操作条件和产品质量等结果与工厂生产装置数据较为一致。通过灵敏度分析发现初馏塔和常压塔塔顶馏出量、常压塔塔底蒸汽量和侧线汽提蒸汽量这几个显著影响拔出率的因素,为原油蒸馏操作优化方案的制定奠定基础。     

Pro/Ⅱ软件模拟及优化酸性水汽提塔

利用Pro/Ⅱ软件对炼油厂酸性水汽提塔进行模拟,考察了冷热进料比、侧线采出位置、侧线采出量及热进料温度等因素对酸性水汽提塔的操作影响。结果表明:该模型可以对实际操作工况进行分析,并提出了操作优化参数及注意要点,对酸性水汽提装置的设计及实际操作调整具有指导意义。     

润滑油加氢装置分馏塔带水的处理及优化

中海油40万吨/年润滑油加氢装置在开工及正常生产期间,因分馏进料带水、汽提蒸汽温度不够高而使蒸汽带水、油运时提前投汽提蒸汽等原因造成的分馏塔带水,导致分馏塔进料加热炉炉膛负荷偏大、分馏塔顶温度和塔压出现反复大波动、塔底泵抽空频繁、分馏塔侧线产品带水浑浊、产品质量不合格等典型问题,延误整个分馏系统顺利开工进度的同时也影响着产品质量,直接影响到装置的经济效益。文章通过分析分馏塔带水的原因,从工艺、设备、操作等多个角度出发,结合实际经验,通过排除分馏进料带水、及时调整C-201顶的回流量以控制塔顶温度及塔顶压力、及时关注塔底泵运行情况、尽量提高汽提蒸汽的温度等措施优化调整分馏操作,有效地缩短了开工周期,确保了产品质量合格,实现了装置运行的安,稳,长,满,优。     

醋酸乙酯生产装置中精馏分离系统的模拟和优化

本文采用Aspen Plus模拟软件对现有的醋酸乙酯生产装置中精馏分离系统进行了模拟和优化,考察了回流比、回流温度和进料温度等因素对酯化塔塔顶粗酯和精制塔塔底醋酸乙酯产品质量的影响,进一步优化了醋酸乙酯工业生产条件。模拟优化结果表明,酯化塔最佳操作条件为塔顶回流温度为25℃、回流比为2.75;精制塔最佳操作条件为塔顶回流温度40℃、回流比为2.34和进料温度为50℃。与现有生产装置相比,两塔节省0.5 MPa蒸汽5 t/h,7℃冷冻水520.5 t/h。     

Aspen Plus软件模拟及优化酸性水汽提塔

文章利用Aspen Plus软件对酸性水汽提塔进行了模拟,并在侧线采出位置、热冷进料配比、热进料温度及进料氨浓度等四个方面对汽提塔进行了分析及优化,确定了该塔操作的最佳条件及注意要点。     

氨蒸馏工艺中蒸氨塔的模拟计算

以AspenPlus软件为平台,对氨蒸馏工艺的蒸氨塔进行了模拟计算。通过对塔板数、进料位置、回流比与进料热状态的模拟,研究了各参数的影响特点。认为塔板数宜取大一些,进料位置靠近塔下端有利,回流比的选择应首先考虑满足产品质量,进料温度接近泡点为佳。确定塔板数8,在第6块塔板处进料,进料温度100℃,回流比1,灵敏板为第7块塔板,得到塔顶液氨产品氨摩尔浓度〉99．5％,塔底残留液氨摩尔浓度〈5％,满足设计规定。     

炼油减压精馏塔汽提工艺传质过程模拟与分析

为了揭示减压塔汽提工艺的传质过程特性,进而改进汽提操作,采用改进的减压精馏过程模拟方法和传质计算方法,分析了炼油常减压装置的汽提工艺的传质特点。在深化对于汽提工艺的理解基础上论证了采用填料汽提塔(段)的必要性以及设计、分析的基本方法。计算分析结果表明侧线汽提塔内填料分离性能保持恒定,汽提塔的分离效率与减压塔对应分离段接近,所以在设计和操作中应给予汽提塔(段)充分重视。减压塔底汽提段的工艺和水力学特点与侧线汽提塔相同。塔底汽提蒸汽质量流率应小于减压塔进料质量流率1%,否则将导致减压塔整体分离效率降低。     

利用Petro-SIM优化常减压装置汽提蒸汽量

利用英国KBC公司开发的Petro-SIM软件对常减压蒸馏装置操作进行模拟。通过对模型操作参数的调整,分别模拟初馏塔汽提蒸汽量和常压塔汽提蒸汽量对常减压蒸馏装置侧线产品质量、轻油收率和装置能耗的影响,以选择合适的汽提蒸汽量,达到优化汽提蒸汽量、指导装置节能的目的。     

加氢裂化尾油中轻组分的分离

针对蜡油加氢裂化装置尾油中轻组分含量较高,对分馏塔进行了诊断和操作优化研究,发现分馏塔存在柴油返回位置低于过汽化油口、汽提蒸汽进料位置较高、汽提蒸汽量不足、尾油循环量大、塔压控制较高等问题.采用ProII对主分馏塔存在的问题进行模拟计算,为分馏塔的改造及优化提供数据.通过提高汽提蒸汽量、降低尾油循环量、降低塔压等操作优...     

佛山市顺德新城区降水中污染物的监测和分析

为掌握佛山市顺德新城区降水中污染物的情况,2015年7月至8月,文章作者分别在雨天进行了降水取样,对降水中的pH、电导率、常见阴离子(F-、Cl~-、NO_3~(2-)、SO_4~(2-))及部分重金属(铅和镉)进行监测分析。选择有相关数据的珠江三角洲和石家庄、厦门等地的降水中污染物的情况进行对比。结果表明,顺德新城区降水中的p H和部分阴离子浓度优于珠江三角洲平均值,酸雨类型属于硫酸和硝酸混合型;其水体洁净程度略差于石家庄;铅和镉的浓度也高于厦门,甚至部分超出了人体能直接接触的安全范围。     

Metabolism of trideuterated iso-lignoceric acid in rats in Vivo and in human fibroblasts in culture

Saturated very long chain fatty acids (fatty acids with greater than 22 carbon atoms; VLCFA) accumulate in peroxisomal disorders, but there is little information on their turnover in patients. To determine the suitability of using stable isotope-labeled VLCFA in patients with these disorders, the metabolism of 22-methyl[23,23,23-²H₃]tricosanoic (iso-lignoceric) acid was studied in rats in vivo and in human skin fibroblasts in culture. The deuterated iso-VLCFA was degraded to the corresponding 16- and 18-carbon iso-fatty acids by rats in vivo and by normal human skin fibroblasts in culture, but there was little or no degradation in peroxisome-deficient (Zellweger’s syndrome) fibroblasts, indicating that its oxidation was peroxisomal. Neither the 14-, 20-, and 22-carbon iso-fatty acids nor the corresponding odd-chain metabolites could be detected. In the rat, the organ containing most of the iso-lignoceric acid, and its breakdown products, was the liver, whereas negligible amounts were detected in the brain, suggesting that little of the fatty acid crossed the blood-brain barrier. Our data indicate that VLCFA labeled with deuterium at the ω-position of the carbon chain are suitable derivatives for the in vivo investigation of patients with defects in peroxisomal β-oxidation because they are metabolized by the same pathways as the corresponding n-VLCFA. Moreover, as iso-VLCFA and their β-oxidation products are readily separated from the corresponding n-fatty acids by normal chromatographic procedures, the turnover of VLCFA can be more precisely measured. A preliminary report of part of this work (Reference 18) was presented at the 5th International Symposium on the Synthesis and Applications of Isotopes and Isotopically Labelled Compounds, Strasbourg, France, June 20–24, 1994.     

Denitrification in shallow groundwater in a coastal agricultural area in Japan

In a coastal agricultural area in the central part of Japan (Shizuoka), we found decreasing nitrate concentration with depth in a shallow groundwater, where the depth to water table varied between 0.6 and 1.2 m below ground surface. High nitrate concentrations (5–29 mg N L^–1) were often observed in the upper layer (0–2 m) of the groundwater, but the concentration decreased to less than 1 mg N L^–1 in the deeper layer. Ammonium was scarcely detected, and the concentration of dissolved oxygen was usually low (< 1 mgO₂ L^–1) in the groundwater. Nitrate in the groundwater often had very heavy nitrogen stable isotope ratios (>20{}). There was a negative relationship between nitrogen stable isotope ratio of nitrate and its concentration. When nitrate was injected into the groundwater with acetylene and bromide (a conservative tracer), nitrate concentration decreased to 20% of the initial level within 5 days, accompanied by the increase in nitrite and nitrous oxide concentration and a little change in bromide concentration. These results indicate that microbial denitrification plays a potential role in the decrease of nitrate in shallow groundwater at the study site.     

我国硝酸工业生产技术新进展

系统叙述了我国硝酸工业2000-2007年生产现状及主要技术成果,尤其指出了国产"四合一"机组的成功投运,使我国硝酸国产化装置取得较大的进步,表现在吨酸的铂耗、氨耗和能耗等方面接近国外引进装置水平,同时介绍了国外双加压法硝酸生产技术的进展.我国已成为硝酸生产大国,仍需以先进的技术改造和发展我国硝酸工业,确保我国硝酸工业健康有序地发展,加快从硝酸生产大国向强国迈进的步伐.     

高效液相色谱法分析化妆品中微量成分的研究进展

综述了高效液相色谱法在化妆品中防腐剂、防晒剂中紫外线吸收剂以及性激素的检测等几个方面的应用;同时,介绍了分析所用的色谱柱、流动相、使用的检测手段以及样品的提取方法;最后针对目前存在的问题,提出了高效液相色谱用于化妆品中微量成分分析的研究方向和发展前景。