甲烷对稠环芳烃加氢裂化反应的促进作用

通过湿浸渍法制备负载型Zn-Ag/Hβ催化剂,采用XRD、SEM、XPS、Py-IR、NH₃-TPD和N₂吸附-脱附等手段进行表征。在稠环芳烃的加氢裂化反应过程引入甲烷,研究了甲烷对Zn-Ag/Hβ催化剂作用下稠环芳烃的加氢裂化反应过程的促进作用,并考察了甲烷引入比例、反应温度、反应压力等条件对稠环芳烃加氢反应萘转化率和苯、甲苯、二甲苯（BTX）等产物选择性的影响规律。结果表明：Zn-Ag/Hβ催化剂具有丰富的中强酸中心,负载金属Zn后分子筛存在Zn²⁺和进入分子筛晶体骨架的Zn物种,总酸量降低且Lewis/Brønsted（L/B）酸量比增加;在反应压力3.5 MPa、反应温度400 ℃、体积空速4 h^-1、气/油体积比800、氢气和甲烷混合气氛的条件下,以萘为模型化合物在Zn-Ag/Hβ催化剂的作用下进行加氢裂化反应,萘转化率为99.82%,液体收率为80.88%;与氢气气氛下相比,BTX总选择性、苯、甲苯和二甲苯的选择性均显著提高。甲烷参与反应对提高BTX选择性和液相收率有利,促进了萘加氢裂化反应产物中含有甲基侧链产物的选择性,该研究结果为高效利用宝贵的重质油资源提供一个新的途径。     

稠环芳烃在蜡油加氢裂化装置分布规律研究

加氢裂化尾油用作蒸汽裂解制乙烯原料的比例在逐渐增大,其性能通常用芳烃指数(BMCI值)来表征。稠环芳烃(PAHs)广泛存在于重质油中,通常尾油中的PAHs质量分数不大于70 mg/g。蒽及三亚苯等三环或四环芳烃在气相中比例基本不超过10%,而晕苯及卵苯等七环及以上芳烃几乎全部富集在油相中。97%(质量分数,下同)的三亚苯富集在煤油中,99%的蒽富集在柴油中,67%的卵苯富集在柴油中,99%的晕苯富集在尾油中。通过提高汽提蒸汽量使塔内油气分压变小,该措施对芳环数较少的PAHs汽提效果比较明显,对晕苯等PAHs汽提效果有限。     

活性金属对含甲烷氛围稠环芳烃加氢转化性能的影响

在Hβ分子筛上负载不同活性金属制备了系列催化剂,利用GC、XRD、N₂吸附-脱附、Py-IR、NH₃-TPD等方法对催化剂进行了表征,并以萘为模型化合物,考察了催化剂在CH₄-H₂混合气氛下对稠环芳烃加氢裂化反应过程的影响。实验结果表明,负载的活性金属均可以均匀分散在Hβ分子筛表面,促进萘加氢开环,萘转化率均达到80%以上。其中,Zn/Hβ,Cu/Hβ,Co/Hβ催化剂的主要产物为甲苯和二甲苯,表明CH₄被活化并参与了反应,提高了含甲基侧链芳烃的加氢裂化产物选择性。尤其是Zn/Hβ催化剂,在CH₄-H₂气氛下,表现出高液相收率和高苯-甲苯-二甲苯混合物选择性,分别为91.34%和56.78%。研究结果可为重质油和天然气资源的高效利用提供新的方向。     

生物工程用稠环芳烃衍生物

对应用于生物工程的萘、芴、芘、蒽、苊等稠环芳烃衍生物作了概括介绍。     

全二维气相色谱法测定柴油中的总芳烃及稠环芳烃含量

应用全二维气相色谱（GC×GC）法的方法原理和族分离特性，研究建立了一次进样即可完成柴油馏分的非芳烃、一环芳烃、二环芳烃、和三环及以上稠环芳烃的分离、定性和定量。该方法的加标回收率在95．1％～104．6％，对稠环芳烃测定的重复性相对标准偏差（RSD）≤5．60％，对总芳烃测定的重复性RSD≤1．26％，与ASTMD2425中间馏分烃类组成测定的标准方法（质谱法）测定结果相比，平均相对平均偏差（RAD）≤5．68％。该方法具有操作简单、快速、准确等优点，完成一个实验仅需70min。     

润滑油中稠环芳烃含量的测定

介绍了制定等同于英国标准IP346—1996“未使用润滑油基础油及无沥青质石油馏分中稠环芳烃测定——二甲基亚砜折光指数法”测定方法的实验室建立过程。通过验证,所建立的试验方法重复性和再现性满足IP346方法精度的要求,该方法的建立为国内润滑油的研究开发和方法标准的完善提供了一种新的检测手段,并为国内润滑油研究与世界同步提供支持。     

氮化物和稠环芳烃对页岩油催化裂化的阻滞作用

以页岩油（试样A）为原料,在常温、常压下,分别经盐酸溶液和盐酸-糠醛溶液萃取,可得试样B和试样C。于微反装置中,在反应温度为520℃,催化剂/原料油（质量比）为6,质量空速为12 h-1的条件下,对试样的催化裂化性能进行了评价。结果表明,与试样A相比,试样B和试样C的密度、残炭质量分数、相对分子质量和含氮质量分数均降低;试样B和试样C的碱性氮化物脱除率分别为81.1%,88.0%;与试样A相比,试样B的饱和分提高了16.61个百分点,胶质和沥青质下降了16.88个百分点;试样C的饱和分较试样B仅提高2.33个百分点,芳香分降低3.63个百分点。在相同的反应条件下,试样催化裂化性能优劣依下列顺序递减:试样C,试样B,试样A。     

Impact of refining on the levels of 4-hydroxy-trans-alkenals,parent and oxygenated polycyclic aromatic hydrocarbons in soybean and rapeseed oils

4-Hydroxy-2-trans-hexenal (4-HHE), 4-hydroxy-2-trans-nonenal (4-HNE), polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAHs (oxy-PAHs) are harmful compounds that commonly occur in edible oils. In this study, we assessed the levels of these compounds in soybean and rapeseed oils during refining. The concentrations of 4-HHE, 4-HNE, 16 PAHs and five oxy-PAHs in soybean oil decreased from 16.27, 644.19, 48.72 and 20.04 μg/kg to 5.65, 260.01, 19.71 and 2.04 μg/kg, respectively, after refining. In rapeseed oil they decreased from 21.46, 246.44, 38.02 and 6.56 μg/kg to 0.00, 37.35, 17.25 and 2.04 μg/kg, respectively. Furthermore, the compounds were sequentially reduced throughout the refining process. The most significant reduction in PAHs was attributed to neutralization (up to 54.79% of the total reduction), while the most significant reduction in oxy-PAHs was attributed to bleaching (up to 84.83% of the total reduction), which also notably reduced 4-HHE and 4-HNE in the soybean oil refining. These results may be helpful for quality and process control with regards to minimizing the levels of harmful compounds in edible oils.     

Development of ANFIS models for polycyclic aromatic hydrocarbons (PAHs) formation in sea sediment

Polycyclic aromatic hydrocarbons (PAHs) are Canceriogenic and mutagenic substances. These compounds are released in the environment by anthropogenic and natural sources. In this work, an adaptive neuro-fuzzy inference system (ANFIS) was employed to model the PAHs formation in sea sediment. Development of ANFIS model is on the basis of the Gaussian membership function. The result obtained by ANFIS model was analyzed with the statistical parameters such as mean squared error (MSE), mean absolute error percent (MEAEP), maximum absolute error percent (MAAEP) and R². The prediction capability of ANFIS model was compared with the previous developed models. According to results obtained by statistical parameters, the ANFIS model has the best performance in estimating of PAHs with the lowest error values.     

多环芳烃对柴油超深度加氢脱硫催化剂运行稳定性的影响

The effect of polycyclic aromatic hydrocarbons (PAHs) on the stability of the hydrogenation catalyst for production of ultra-low sulfur diesel was studied in a pilot plant using Ni-Mo-W/γ-Al2O3 catalyst. The mechanisms of catalyst deactivation were analyzed by the methods of elemental analysis, nitrogen adsorption-desorption, thermogravimetry-mass spectrometry (TG-MS) technology, X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM). The results demonstrated that PAHs had little effect on the activity of catalyst at the beginning of operation, during which the reaction temperature was increased by only 1 — 4 ℃. However, the existence of PAHs significantly accelerated the deactivation of catalyst and weakened the stability of catalyst. This phenomenon could be explained by that the catalyst deactivation is not only related to the formation of carbon deposit, but also is closely related to the loss of pore volume and the decrease of Ni-W-S phase ratio after adding PAHs.     

催化剂级配在加氢裂化装置中的应用

采用催化剂级配技术,对中国石油四川石化有限责任公司2.7 Mt/a加氢裂化装置的两个反应器进行改造;并对调整原料性质及操作条件(尽量接近于第一周期标定工况数据)后的第二周期应用情况进行了催化剂活性、产品分布、产品质量、操作安全性等对比分析。实验结果表明,通过催化剂活性级配和加氢选择性级配,实现了多环芳烃的进一步转化,最大程度保留链烷烃在尾油组分中,与第一周期相比,喷气燃料烟点提高3.0 mm,尾油芳烃指数降低6.5个单位;第二周期转化率(282℃)控制在79%、尾油切割点为252℃工况下,重石脑油与喷气燃料总收率可达60.9%,实现多产重石脑油与喷气燃料的目标;降低了反应器压降和循环氢压缩机的能耗,节约了投资成本。     

Incidence of polycyclic aromatic hydrocarbons in vegetable oil blends

The consumption of extra virgin olive oil has been growing in Brazil over the years. However, as it is an expensive product, many consumers tend to substitute extra virgin olive oil with a cheaper alternative, such as vegetable oil blends (mainly a mixture of olive and soybean oils). In the preset study, different brands of oil blends were evaluated for the occurrence of 13 polycyclic aromatic hydrocarbons. The method involved liquid–liquid extraction with hexane and N,N-dimethylformamide, followed by clean-up by SPE with C18 cartridges. Analyses were carried out by HPLC with fluorescence detection. PAHs were detected in all samples analyzed and the mean sum ranged from 2.59 μg/kg to 85.30 μg/kg. A high variability in PAHs levels between brands and between different batches of the same brand was observed. Approximately 50% of the samples were in disaccording with the maximum permitted levels for BaP and PAH4 established in the Brazilian and/or European regulations.     

Contamination of smoked meat and fish products from Polish market with polycyclic aromatic hydrocarbons

The aim of this work was to determine the level of contamination of different kinds of commercial smoked meat and fish products from Polish market with polycyclic aromatic hydrocarbons (PAHs) for which the limiting values are established in the Commission Regulation (EU) 2015/1125. These PAHs are benzo(a)pyrene (BaP) and the sum of the following four PAHs: benzo(a)pyrene, benzo(a)anthracene (BaA), benzo(b)fluoranthene (BbFA) and chrysene (Chr). The research materials were fish, meat and chicken products smoked by the industrial or traditional techniques. The research methods included process of saponification of the samples, extraction of the polycyclic aromatic hydrocarbons fraction, and then qualitative and quantitative determination of PAHs by high performance liquid chromatography with fluorescence detection method (HPLC-FLD). The highest BaP content and the sum of the four polycyclic aromatic hydrocarbons (4PAHs) (36.51 mg/kg and 73.01 mg/kg, respectively) were found in canned smoked sprats in oil and these values exceeded the maximum levels given in the Commission Regulation (EU) 2015/1125. The analyzed products smoked by traditional technique contained significantly more PAHs as compared to the products smoked by the industrial technique or produced with smoke flavourings.     

Optimization of biodegradation of polycyclic aromatic sulfur heterocycles in soil using response surface methodology

Abstract

This paper uses response surface methodology based on the Box-Behnken design to investigate the influence of substrate concentration, inoculation quantity and temperature on the biodegradation of polycyclic aromatic sulfur hydrocarbons in oil-contaminated soil by Pseudomonas sp. LKY-5. Substrate concentration is identified as the most important factor through the analysis of variance. The maximum degradation of PASHs can be achieved at the conditions of substrate concentration of 75.77?ml/kg, inoculation quantity of 20.4% and temperature of 30?°C.