高环烷酸原油缓蚀剂的性能评价研究

本文介绍了自行开发的缓蚀剂A与国外缓蚀剂B对环烷酸的缓蚀评价,利用扫描电镜对缓蚀剂吸附膜进行了分析。实验结果表明：在270℃左右,酸值4.0 mgKOH/g的腐蚀介质油中,高温缓蚀剂A、B在金属表面成膜较好,能有效地抑制环烷酸腐蚀。     

环烷酸缓蚀剂的合成及缓蚀性能的应用

以3-氯丙酸乙酯、甲基苯并三氮唑、水合肼、2-吡啶甲酰氯为原料,通过三步法合成反应,合成出了酰胺类抑制环烷酸腐蚀的高温环烷酸缓蚀剂。通过红外、热分析表征,进一步明确了产品的主要官能团及分解温度变化趋势。通过小试得到的工艺参数,确定了中试的反应条件,生产出合格的中试产品。在炼厂常减压装置加注后,分别考察了装置易腐蚀的关键减压侧线油部位,即减二线和减三线油中的铁离子,考察初期即成膜期,高温环烷酸缓蚀剂的加注量为50mg/L,待系统稳定后,加注量稳定在30mg/L的条件下,减二线油和减三线油的铁离子含量由0.92mg/L和0.98mg/L降到0.17mg/L和0.11mg/L,说明加注高温环烷酸缓蚀剂大大降低了环烷酸对炼油装置的腐蚀程度。     

Electrochemical investigations of naphthenic acid corrosion for carbon steel and the inhibitive effect by some ethoxylated fatty acids

The electrochemical behavior and corrosion of carbon steel in various types of naphthenic acid solutions have been studied by using cyclic voltammetry technique. The data reveal that the anodic excursion spans of carbon steel in naphthenic acid solution are characterized by the occurrence of a well-defined anodic peak (peak A), followed by a passive region. The passivation may be related to the formation and precipitation of oxide film on the electrode surface. The data reveal that increasing naphthenic acid concentration enhances the anodic peak current density (I_PA) and shifts its peak potential towards more positive values. The corrosion rate of carbon steel depended critically on the naphthenic acid types. The rate of the corrosion process increased with increasing in molar mass of naphthenic acid, reaching a maximum value in the presence of CHPA acid (C₉), and then decreased.

Potentiodynamic polarization measurements indicated that ethoxylated fatty acid derivatives have a strong effect on the corrosion behavior of the carbon steel in naphthenic acid solutions. The inhibition efficiency of these compounds was found to vary with their nature and concentration. The order of effectiveness of the inhibitors was OL(EO)₈₀ > OL(EO)₄₀ > OL(EO)_20. The adsorption of ethoxylated fatty acid on the carbon steel surface in naphthenic acid solutions was found to obey Frumkin isotherm and kinetic-thermodynamic model.     

直馏柴油脱除环烷酸精制新技术研究

在微波作用下,以辐射时间、辐射功率和辐射压力,研究了微波碱精制法直馏柴油脱酸的工艺条件,在辐射时间5min,辐射功率375W,辐射压力0．05MPa条件下,柴油脱酸率和油品回收率分别达到99．07％和98．62％。精制后油品酸度降低到0．57mgKOH／100mL．柴油性能指标满足GB252-2000轻柴油国家标准。与传统方法相比,微波辐射法无需破乳剂和高压电场。精制过程无乳化现象产生．有利于环境保护。     

High-efficiency separation and extraction of naphthenic acid from high acid oils using imidazolium carbonate ionic liquids

N-alkyl imidazolium carbonate ionic liquids were employed to separate and recover naphthenic acid from model oils.The effects of the cationic and anionic structures of ionic liquids and operating condi-tions on the deacidification performance were investigated.The deacidification performance of tradi-tional organic solvents was also investigated for comparison.The results indicated that the naphthenic acid could be completely removed from the model oil with a small mass ratio of ionic liquid to oil.The extracted naphthenic acid was regenerated with a recovery of up to 92％.In addition,imidazolium carbonate ionic liquids could be successfully regenerated and recycled.The mechanism of interaction between imidazole ionic liquids and the naphthenic acid molecules were explained by Gauss calculation.     

Inhibition of copper corrosion in aerated hydrochloric acid solution by amino-acid compounds

The effect of two amino-acid compounds, dl-alanine and dl-cysteine, on copper corrosion in an aerated 0.5 mol l⁻¹ HCl solution was studied by weight-loss measurements, potentiodynamic polarisation curves, and electrochemical impedance spectroscopy. A conventional benzotriazole (BTA) inhibitor was also tested for comparison. dl-cysteine was shown to be the most effective inhibitor among those tested inhibitors. Potentiodynamic polarisation results revealed that both the dl-alanine and dl-cysteine acted as an anodic inhibitor; however, dl-cysteine, in particular, was more effective, as it strongly suppressed anodic current densities. The improved inhibition efficiency of dl-cysteine in the 0.5 mol l⁻¹ HCl solution was due to its adsorption on the copper surface via the mercapto group in its molecular structure.     

Second row transition metal sulfides for the hydrotreatment of coal-derived naphtha II. Removal of individual sulfur compounds

The disappearance of individual sulfur compounds has been investigated during the hydrotreatment (simultaneous removal of sulfur, nitrogen and oxygen) of coal-derived naphtha over each of the bulk second row transition metal sulfides. The sulfur compounds in the naphtha mainly consist of thiols/sulfides, thiophene and substituted thiophenes. Thiols/sulfides are, in general, more easily converted than thiophenic compounds are. Lighter thiols/sulfides are intermediates in the conversion of higher boiling thiols/sulfides or thiophenes. Side chain alkyl C---C bond breaking is predominant during the disappearance of thiophenes over the Zr and Nb catalysts while C---S bond breaking is predominant over the other catalysts. Thiophenic compounds are hydrogenated prior to desulfurization over the Mo, Ru, Rh and Pd sulfides. Highly substituted thiophenes are the compounds most difficult to convert over the Mo, Ru, Rh and Pd sulfides. The substituted thiophenes exhibit different reactivity trends over molybdenum sulfide, on one hand, and the Group VIII sulfides, on the other, indicating different adsorption modes and surface mechanisms for their conversion over these catalysts. Individual sulfur compounds do not follow first order kinetics and the disappearance rate is limited by product inhibition. The overall removal of sulfur does not follow simple first or second order kinetics since the individual compounds do not react in parallel, independent or first order reactions.     

Influence of impurities on stainless steels corrosion in wet process phosphoric acid

The corrosion behaviour of stainless steels in wet process phosphoric acid was studied by means of polarization curves and corrosion tests; in this context the influence of impurities that enhance the corrosivity of the acid, such as chlorides, fluorides and sulphates, was evaluated. Moreover the efficiency of some corrosion inhibitors, present as impurities in wet-process phosphoric acid, was evaluated by means of polarization curves and corrosion tests. Inhibitors of fluoride aggressiveness such as compounds of silicon, aluminum, magnesium were tested both separately and together. Trivalent iron as an oxidizing agent was also evaluated in order to minimize chloride-induced corrosion. Different grades of stainless steels such as AISI 316 L, Alloy 20, Alloy 28 and a duplex stainless steel 22Cr5Ni type, were taken into consideration.     

Extraction of yttrium using naphthenic acid with different acid numbers

Naphthenic acid with acid number of 100–200 mg KOH/g could be used to extract yttrium in the system of 20% naphthenic acid + 20% n-butanol + 60% n-hexane. A transparent and uniform phase was formed during saponification but did not influence the extraction process. n-Butanol and n-hexane could shorten phase separation time and lessen emulsification. Excess naphthenic acid and ammonia, and non-naphthenic acid substances contributed to emulsification and difficulty in phase separation, which were especially serious in system of 20% naphthenic acid + 20% 2-octanol + 60% kerosene. Naphthenic acid with acid number <100 mg KOH/g was unsuitable for extraction in either system. Extraction percentages were 99% and 46% when being saponified by 12.7 and 6.3 mol/L ammonia, respectively.     

环烷酸模型化合物酯化反应体系的热力学分析

以选取的环烷酸模型化合物为基础,利用热力学方法分析其酯化反应的可能性。由于环烷酸物质结构的特殊性,它们的热力学数据通常无法直接获取,采用了基团贡献法估算酯化反应体系中环烷酸及环烷酸酯在298.15K标准态下的生成焓和标准熵,同时确定了这两种物质等压热容随温度的变化关系,进而得到了不同温度条件下酯化反应的吉布斯自由能变及平衡常数。计算结果表明,酯化反应的平衡常数很大（107）,从而确定了该反应体系的可能性。     

Inhibition of phosphoric acid corrosion of zinc by organic onium compounds and their adsorption characteristics

The inhibiting properties of some organic phosphonium and ammonium compounds were studied with respect to the corrosion of zinc in 1 M H3PO4 solution. It was found that onium compounds which have -electron system(s) are adsorbed following Frumkin's adsorption isotherm and provide better inhibition efficiency than those containing no -electron system. The adsorption of the latter compounds was found to obey Langmuir's isotherm. Both potentiostatic and electrochemical impedance techniques proved that the studied onium compounds act as primary interface inhibitors without changing the mechanism of either hydrogen evolution reaction or zinc dissolution.     

Modifications to the copper strip corrosion test for the measurement of sulfur-related corrosion

The copper strip corrosion test (CSCT) is used to measure the corrosivity of sulfur compounds in hydrocarbon fluids. The CSCT is performed by immersing a strip of cleaned, polished copper in a hydrocarbon fluid at a specified temperature for a predetermined time, then ‘rating’ the strip against a standard. In this work, instead of using the usual large, oblong strips designed to measure 30 mL fluid samples, we used small circular Cu ‘coupons’ as an alternative method for carrying out CSCTs on microscale samples of fluid. The motivations for reducing the scale include: applicability to small samples, ability to archive the small and inexpensive coupons, reduced waste, and potential for automated analysis using autosampler vials as reaction vessels. Moreover, the symmetric circular geometry facilitates the analysis of the images with mathematical color spaces. Mixtures of n-decane:n-tetradecane with varying concentrations of H₂S (from a distillation column) were used as a source of microscale samples of corrosive fluid to demonstrate the viability of the smaller scale CSCT. Additional experimental details concerning the lighting conditions and digital photography of the coupons, measurement of corrosion using color space, and quantification of the sulfur content of the distillate are also described.     

Determination of sulfur compounds in gasoline using mercury film electrode by square wave voltammetry

A sensitive method based on square wave voltammetry is described for the quantitative determination of elemental sulfur, disulfide and mercaptan in gasoline using a mercury film electrode. These sulfur compounds can be quantified by direct dissolution of gasoline in a supporting electrolyte followed by subsequent voltammetric measurement. The supporting electrolyte is 1.4 mol L⁻¹ sodium acetate and 2% acetic acid in methanol. Chemical and optimum operational conditions for the formation of the mercury film were analyzed in this study. The values obtained were a 4.3 μm thickness for the mercury film, a 1000 rpm rotation frequency, −0.9 V applied potential and 600 s depositing time. Voltammetric measurements were obtained using square wave voltammetry with detection limits of the 3.0 × 10⁻⁹, 1.6 × 10⁻⁷ and 4.9 × 10⁻⁷ mol L⁻¹ for elemental sulfur, disulfide and mercaptan, respectively.     

环烷酸的精制工艺研究

用HCI对从柴油中脱除的环烷酸进行精制,考察了各工艺因素对其精制效果的影响,得到最佳工艺条件：酸化温度为55℃、静置时间为3h,水洗温度为90℃和水洗次数为1次,用此优化工艺得到的环烷酸纯度达到98．6％。     

Melamine formaldehyde compounds. The active species in acid catalyzed reactions

Applying results from previously published kinetic investigations on the hydrolysis and condensation of methylol melamine compounds in acid solution a thorough analysis of the reaction mechanism is given. In the literature it has been discussed whether the acid catalysis takes place by protonation of the triazine ring, if it is a protonation of the methylol side groups or if both types of protonation are active.In the present paper strong support is given to a kinetic model where the side group activated species are the reactive ones. Ring protonation, on the other side, leads to deactivation. Included are also computer simulations in Matlab of the decomposition of tri- and hexa-methylol melamine in dilute solution, assuming the hydrolysis to take place by series first order reactions. The computer simulations allow us to calculate the relative composition of the reaction mixture as a function of time and to see the effect of changes in the experimental rate constant as the reaction proceeds.     

有机膦酸缓蚀剂的研究发展现状

介绍了缓蚀剂的类型、缓蚀机理和缓蚀性能,比较了各种缓蚀剂的特点,认为有机膦缓蚀剂具有无毒性、污染小的特点,尤其在应用于高硬度、高pH值和高温水系统时有较好的表现。     

Reductive pyrolysis study of sulfur compounds in different Tabas coal samples (Iran)

A comparative study of the effects of mineral and pyrite removal on the determination of organic sulfur functionalities in representative, as well as its low and high sulfur analogue samples of Tabas coal (C1 seam) were studied by atmospheric pressure-temperature-programmed reduction (AP-TPR) method. The AP-TPR investigation showed the presence of di-aryl sulfides, aryl-alkyl sulfides, simple and complex thiophenic structure in all representative, low and high sulfur samples. There is no indication of the presence of pure di-alkyl sulfides, disulfides or thiols, nor oxidised sulfur forms in the samples. Only minor differences in sulfur functionalities were detected qualitatively between the three analogue samples. Quantitatively differences in sulfur forms were found to be more pronounced. The presence of CH fragments on gases emitted during AP-TPR investigation of demineralised and demineralised pyrite-free samples, shows evidence for the formation of shorter CH chains and of polyaromatic compounds, and lower molecular weight material in the demineralization and pyritic sulfur removal stages.     

酸洗过程中的缓蚀剂

通过对近十年来酸洗缓蚀剂的研究工作的介绍与分析,结合清洁生产的要求及定量化计算数据,明确指出酸洗缓蚀剂在酸洗废液减量化的意义,并对进一步研究与开发绿色酸洗缓蚀剂提出值得重视的几个问题。     

盐酸介质金属缓蚀剂最新进展

对盐酸介质中金属材质腐蚀的机理以及研究现状进行了分析和概述。目前,人们认识到金属材质在盐酸溶液中腐蚀速度与酸度和氯离子浓度有关。而针对就盐酸溶液中的氯离子以及氢离子在金属的腐蚀过程发挥多大的功效,以及金属材质的阳杉阴极反应是如何进行的动力学问题的研究成为该领域的主要趋势,以解决金属材料在盐酸介质中腐蚀问题。     

盐酸介质中新型缓蚀剂研发进展

对盐酸介质中金属材质腐蚀的机理以及研究现状进行了分析和概述。对缓蚀剂的研发做出了展望。