Near Infrared Spectroscopic Determination of Diesel Fuel Parameters Using Genetic Multivariate Calibration

Abstract

The use of full spectral region from near infrared spectroscopic analysis does not always end up with a good multivariate calibration model as many of the wavelengths do not contain necessary information. Due to the complexity of the spectra, some of the wavelengths or regions may, in fact, disturb the model-building step. Genetic algorithms are one of the useful tools for solving wavelength selection problems and may improve the predictive ability of conventional multivariate calibration methods. This study demonstrates application of genetic algorithm-based multivariate calibration to near infrared spectroscopic determination of several diesel fuel parameters. The parameters studied are cetane number, boiling and freezing point, total aromatic content, viscosity, and density. Multivariate calibration models were generated using genetic inverse least squares (GILS) method and used to predict the diesel fuel parameters based on their near infrared spectra. For each property, a different data set was used and in all cases the number of samples was around 250. Overall, percent standard error of prediction (%SEP) values ranged between 2.48 and 4.84% for boiling point, total aromatics, viscosity, and density. However, %SEP results for cetane number and freezing point were 11.00% and 14.86%, respectively.     

乙醇柴油的物化性质研究

分析了乙醇柴油的相溶性、十六烷值、密度、运动粘度、凝点和冷滤点、腐蚀性、闪点和馏程等性质。考察了乙醇含量及助溶剂对乙醇柴油物化性质的影响。结果表明,乙醇体积分数升高相溶性变差,在50％左右相溶性最差;加入助溶剂能明显改善乙醇和柴油的相溶性。十六烷值随乙醇体积分数升高而减小,乙醇体积分数为10％时十六烷值减小约5个单位;加入乙醇后,柴油的密度、运动粘度都有不同程度的减小;腐蚀性和凝点变化不大。乙醇柴油的闪点接近乙醇的闪点,初馏点接近乙醇的沸点。最后对乙醇柴油产品标准的制定提出了建议。     

近红外光谱在喷气燃料分析中校正模型的建立

以冰点为例，详细介绍了采用ZX440近红外多组分油料分析仪建立喷气燃料质量指标校正模型的流程和方法；对采用该仪器建立喷气燃料芳烃含量、烯烃含量、总硫含量、馏程、闪点、密度、净热值等质量指标校正模型的研究结果进行了概括。结果表明，采用该仪器可实现对上述质量指标的准确测定。讨论了该仪器对喷气燃料质量指标进行机动分析化验的适用性。     

劣质原料油加氢改质技术的应用优化研究

研究了两种不同劣质原料油通过加氢改质反应生产优质国Ⅵ柴油调合组分。首先,在相同工艺条件下,考察了原料油性质对加氢改质产品分布以及性质的影响;其次,以此两种劣质原料油加氢改质所得的混合柴油为对象,考察轻、重柴油切割点对柴油密度、组成、十六烷值等性质的影响。结果表明：随着轻、重柴油切割点的提高,轻柴油与重柴油的密度、链烷烃含量以及十六烷值均逐渐增加;轻柴油十六烷值低,是劣质的柴油调合组分,但可以作为催化裂化原料;重柴油十六烷值高,但由于其凝点高,需要将其中更重的组分切出后,才能够作为优质的0号国Ⅵ柴油调合组分;对于上述两种混合柴油,轻、重柴油切割点控制在230℃,在控制凝点为0℃的前提下,重柴油组分收率最高,而且十六烷值能够满足国Ⅵ柴油标准要求。     

NEURAL NETWORK PREDICTION OF CETANE NUMBERS FOR ISOPARAFFINS AND DIESEL FUEL

A backpropagation neural network was used to correlate and predict the cetane numbers of isoparaffins and diesel fuels. For the isoparaffins, the correlation was made between the chemical structure of the branched paraffins and their cetane number. Thirteen branched paraffins were employed to train the network. The group additivity method was used to express the degree of branching of the isoparaffins. According to their positions in the molecule structure, three carbon groups (methylene [-CH₂-] subdivided into methylene α, β and γ, or further, to a carbon that is not a methylene, methyne [>CH-] and quaternary carbon [>C<]) were regrouped into four categories, and included along with normal boiling points, as the network inputs. For the selected diesel fuels, different combinations of physical properties such as density, viscosity, aniline point, and distillation temperatures were tested as the neural network input. The best model was obtained using density, viscosity, aniline point and ASTM D86 measured distillation temperatures (IBP, 10%, 50%, 90% and FBP) as inputs. The trained network models, when applied to predict the cetane number of other isoparaffins and diesel fuel, were quite accurate.     

单段加氢裂化催化剂F4402B的工业应用

大庆石化分公司炼油厂260kt/a高压加氢裂化装置首次采用抚顺石油化工研究院开发的F4402B加氢裂化催化剂进行了工业应用试验。试验结果表明,该催化剂具有较高的加氢脱氮和异构化能力及中间馏分油选择性,以大庆常三线和减一线混合油为原料,石脑油馏分、中间馏分油和大于350℃尾油的产率分别为17．1％、71．0％和11．1％,能大量生产十六烷值为59．8、凝点为－41℃的－35号低凝柴油组分和十六烷值为76．3、凝点为－1℃的0号柴油组分,石脑油及尾油可分别作为催化重整和裂解的优质原料。     

Application of Vibrational Spectroscopy to the Determination of Viscosity and Aniline Value of Hexanol Blended Diesel

Presently there is a great interest in the development of green fuels capable of producing reduced emissions. The two parameters, among many others, that determine the efficiency of the fuel are the viscosity and aniline point of the fuel. The authors present a vibrational spectroscopy-based analytical method for the estimation of viscosity and aniline value of the 5–45% hexanol blended diesel. The infrared (IR) and near infrared (NIR) spectra of the blended diesel were recorded in the range of 4000–700 cm^?1 and 9000–5000 cm^?1. The major peaks in both spectra were assigned to the fundamental and overtone vibrations of the CH and OH functional groups. The PLS (partial least square) analysis of the spectra showed that both IR and NIR spectra can be successfully used as alternative tools for the determination of the viscosity and aniline value of the hexanol blended diesel fuel. The high correlation coefficients (R²) for the viscosity and aniline values in the IR (0.994, 0.996) and NIR (0.995, 0.996) indicated the success of the procedure.     

红外光谱法用于快速测定车用柴油酸度等性质的研究

针对车用柴油酸度等性质测定过程繁琐，采用衰减全反射样品池测定车用柴油的红外光谱，用偏最小二乘法（PLS）建立红外光谱测定车用柴油酸度、密度、闪点和凝点的4个校正模型，验证标准误差分别为0.46 mg/(100 mL),0.77kg/m3,2.60 ℃,2.77 ℃，该方法符合标准方法再现性要求。与标准方法相比，该方法具有无需预处理、操作简单、测量快速、重复性好等优点。     

红外光谱法用于快速测定车用柴油酸度等性质的研究

针对车用柴油酸度等性质测定过程繁琐，采用衰减全反射样品池测定车用柴油的红外光谱，用偏最小二乘法（PLS）建立红外光谱测定车用柴油酸度、密度、闪点和凝点的4个校正模型，验证标准误差分别为0.46 mg/(100 mL),0.77kg/m3,2.60 ℃,2.77 ℃，该方法符合标准方法再现性要求。与标准方法相比，该方法具有无需预处理、操作简单、测量快速、重复性好等优点。     

两段法柴油深度加氢处理的探索研究

对采用两段法加氢工艺加工某催化裂化柴油得到的芳烃质量分数低于25％的产品柴油窄馏分的性质进行了分析。结果显示,经两段加氢得到产物270—300℃馏分段的密度和芳烃含量最高;十六烷值随馏程增加而升高,当油品的沸点在150～300℃时,十六烷指数与十六烷值基本一致;沸点再升高,油品的十六烷指数与十六烷值的差值变大。据此推测出适当提高催化裂化柴油的终馏点,二段装填孔结构有利于270—300℃馏分扩散的、具有一定开环裂化功能的加氢催化剂是进一步改善该类工艺的方向。     

Properties Correlations and Characterization of Athabasca Oil Sands-derived Synthetic Crude Oil

Narrow fractions of Athabasca oil sands-derived synthetic crude oil (SCO) from Canada were obtained by distillation at 20 oC to 500 oC and characterized. The yield and properties, such as density, refractive index, viscosity, freezing point, sulfur and nitrogen content and UOP K-index, were correlated as a function of boiling temperature (Tb). The properties of naphtha fractions, jet fuel and diesel fractions could be predicted accurately with the correlations, which are useful for process design considerations, such as optimizing operating conditions of refinery processing units. The other key properties and characteristics of naphtha fractions, jet fuel, diesel and vacuum gas oil were also determined.     

低温法费-托合成油加氢提质CFH~L技术开发及工业应用

介绍了中国石化石油化工科学研究院开发的低温法费-托合成油加氢提质CFH~L技术及工业应用情况,考察了操作条件对异构加氢裂化反应效果的影响。结果表明,反应温度、氢分压、体积空速对异构加氢裂化反应效果影响显著,氢油体积比影响较小。CFH~L技术工业应用结果表明,稳定加氢柴油馏分十六烷值为81,凝点小于-20℃;异构加氢裂化柴油馏分选择性为82.2%,异构裂化柴油馏分十六烷值为76,凝点为-53℃。     

柴油深度加氢脱硫脱芳烃工艺技术的研究与开发

对不同性质的柴油，可采用不同的加氢脱硫脱芳烃工艺技术生产清洁柴油。直馏柴油和焦化柴油采用单段加氢工艺技术，在适宜的工艺条件下，可以生产硫质量分数低于300μg／g、芳烃质量分数低于25％、十六烷值大于53的清洁柴油；劣质催化裂化柴油采用单段加氢工艺及催化剂匹配装填技术，在适宜的工艺条件下，可以生产密度0．8576g／cm^3、硫质量分数5．0μg／g、芳烃质量分数29．6％、十六烷值39.8的清洁柴油组分；劣质催化裂化柴油采用两段加氢工艺技术，可以生产密度0．8506g/cm^3、硫质量分数1．2μg／g、芳烃质量分数16．5％的清洁柴油组分。     

CCD近红外光谱仪在柴油生产控制分析中的应用

介绍了电荷耦合器件（ Ｃ Ｃ Ｄ）近红外光谱仪在柴油生产控制分析中的应用,通过对直馏柴油、加氢精制柴油及成品柴油十六烷值、密度、凝点、闪点及馏程等质量指标的测定及与标准测定方法的对比,验证了近红外光谱测定柴油性质的可靠性。试验证明,近红外方法具有分析速度快、重现性好、分析成本低等特点。     

汽柴油调合常用质量指标的设计计算方法

探讨了汽柴油调合常用质量指标的计算方法,包括辛烷值、蒸气压、凝点、闪点、十六烷值和黏度。在众多计算方法之中,筛选出了比较实用的方法,并对某些计算方法进行了改进。所推荐的方法均具有计算精度高、适用范围广、计算快捷方便等优点,非常适用于设计计算过程,对炼油生产过程中的产品调合环节也具有一定的参考价值。     

油砂沥青改质所得中间馏分生产柴油和喷气燃料的研究

对Athabasca油砂沥青进行改质可以得到轻瓦斯油窄馏分,研究了将这些轻瓦斯油窄馏分作为柴油和喷气燃料时的性能。分析了轻瓦斯油窄馏分的馏程、十六烷值、烟点以及其他性质如芳烃含量、苯胺点、硫氮含量之间的关系。研究表明,选择合适的加工流程、选取恰当的馏分可生产出符合当前严格环境法规和未来产品规格要求的柴油和喷气燃料。同时,回归出了预测十六烷值和烟点的新型关联式,其变量包括密度、模拟蒸馏馏程、采用超临界流体色谱法测定的单环芳烃含量及总芳烃含量;这些关联式可用来预测油砂沥青改质得到的宽馏程中间馏分的十六烷值和烟点。     

用柴油的烃族组成预测十六烷值和密度

用柱色谱和GC-MS方法测定了柴油的13种烃族组成，分别是：(1)链烷烃，(2)一环环烷烃，(3)二环环烷烃，(4)三环环烷烃，(5)烷基苯，(6)茚满萘满，(7)茚类，(8)萘，(9)烷基萘，(10)苊类，(11)苊烯，(12)三环芳烃，(13)胶质。采用线性最小二乘法拟合得到了柴油的十六烷值和密度与其13个烃族组成的关联式，统计检验结果并将计算值与实验值进行比较，结果表明，用烃族组成预测柴油的十六烷值和密度能够得到令人满意的结果。     

兼产喷气燃料和重整原料MHUG技术的工业应用

介绍了MHUG技术用于加工低十六烷值的环烷基柴油原料,兼产部分喷气燃料和重整原料及高十六烷值柴油产品的中试结果以及该技术在中海石油炼化有限责任公司炼油分公司3.6 Mt/a大型工业装置上的运转情况。从工业应用结果来看,在较缓和的工艺条件下,MHUG技术加工低十六烷值的环烷基柴油原料可生产满足欧Ⅴ排放标准的优质柴油及3号喷气燃料和高芳烃潜含量重整原料。     

Parametric equations relating the main physicochemical characteristics of off-standard diesel fuels

On the basis of published data, parametric equations relating the basic physicochemical characteristics of off-standard diesel fuels, i.e., the cetane number, the density, and the sulfur content, were derived. These equations make it possible to calculate, knowing one of the above parameters of diesel fuel, the other two values and, thereby, to predict the performance characteristics of off-standard diesel fuels.     

Influence of the hydrocarbon composition of diesel fuels on their performance characteristics

The influence of different groups of diesel hydrocarbons on the physicochemical properties and performance characteristics of diesel fuels has been considered. The parameters to be evaluated have been cetane number, cetane index, diesel index, pour point, and cold filter plugging point. It has been shown that the hydrocarbon group composition, which reflects only the amount of arenes and paraffinic-naphthenic hydrocarbons, gives insufficient information for prediction of the performance properties of fuels. A more detailed study of the hydrocarbon composition of each group of compounds—the ratio of mono-, bi-, polycyclic arenes, the concentration and the ratio of high- and low-melting-point n-alkanes and isoalkanes—has made it possible to reveal the influence of each group on individual fuel characteristics.