催化裂化辛烷值助剂的研究进展

催化裂化辛烷值助剂是催化裂化工艺中的重要组成部分,广泛应用于催化裂化装置以提高汽油辛烷值。介绍了几种辛烷值助剂并详细论述了ZSM-5辛烷值助剂的研究进展。最后,对催化裂化辛烷值助剂未来的研究方向进行了展望。     

提高催化裂化汽油辛烷值的技术思路探索

在分析催化裂化汽油馏分单体烃辛烷值特点的基础上,确定了理想的汽油高辛烷值组分,并系统考察了反应深度对大庆蜡油催化裂化反应所得汽油辛烷值和高辛烷值组分含量影响的差异,同时研究了汽油烯烃催化转化生成高辛烷值组分的可行性。结果表明,不同重油催化裂化反应深度下,汽油的烃组成和辛烷值的差异较大,不同烃族对辛烷值的贡献不同。适宜反应条件下,富含C_5~C_7烯烃的汽油和大分子烯烃均可转化为高辛烷值组分。     

车用乙醇汽油抗爆指数与敏感性研究

采用车用乙醇汽油样品作为试样,根据GB/T 5487-2015和GB/T 503-2016方法要求测试其研究法辛烷值RON和马达法辛烷值MON。考察RON与MON关系,进而给出研究法辛烷值与汽油敏感性之间的关系,通过多项式拟合,使得马达法辛烷值的预测水平较高,同时预测马达法辛烷值在标准燃料配制过程中所产生的经济效益进行详细阐述。马达法辛烷值的预测结果表明:针对某一汽油样品时,马达法辛烷值预测值与实测值偏差为0.5个单位。     

汽油辛烷值提高与成品汽油优化控制探讨

辛烷值提高对于炼油企业降本增效起着关键作用,文章从理论与实际调整探讨了汽油辛烷值提高、S-Zorb辛烷值损失控制与成品汽油的辛烷值富余量控制,并对优化控制过程进行了总结。     

提高催化裂化汽油辛烷值方法的研究进展

辛烷值是汽油质量的主要指标之一,提高汽油辛烷值,生产高品质汽油是炼油工业的重要任务。文章综述了提高催化裂化汽油辛烷值方法的研究进展,包括优化催化裂化装置操作条件、添加汽油辛烷值促进剂及采用新工艺技术等,对提高催化裂化汽油辛烷值方法的研究方向进行了展望。     

MTBE辛烷值测试法的探讨

MTBE作为调合生产高标号无铅汽油的重要的高辛烷值组分油，准确测试其辛烷值在汽油调和生产中具有重要的意义。初步探讨了MTBE研究法辛烷值的测试方法，尝试了用甲苯标准燃料做参比燃料直接测定其净辛烷值，同时也测定了MTBE的混配辛烷值，通过MTBE辛烷值的测试，了解了MTBE的调和效应，确认了在石油二厂无铅汽油调和生产中对催化汽油的MTBE的真实辛烷值约为108／RON，指导了车用无铅汽油的调和生产。     

基于拉曼技术的汽油辛烷值测定系统设计

汽油辛烷值的实时检测对生产高品质的汽油及控制调和装置具有重要意义。针对传统辛烷值检测方法的不足,设计了基于拉曼分析技术的汽油调和过程中辛烷值的测定系统。系统由拉曼光谱检测、汽油拉曼光谱数据的预处理、汽油辛烷值预测模型组成。实践证明,该辛烷值测定系统能够准确检测调和过程中汽油辛烷值,并实时显示调和过程中汽油拉曼谱图。     

提高汽油辛烷值测定准确性降低汽油生产成本

辛烷值是表示点燃式发动机燃料抗爆性的一个约定数值,判定辛烷值的目的是判断汽油抗爆性能的优劣。本文研究了汽油辛烷值机的原理与构造及影响辛烷值测定准确性的因素,通过调整试验机参数、提高分析的重复性和再现性等有效措施,提高辛烷值测定的准确性,降低汽油生产成本。     

非金属汽油辛烷值改进剂工业应用分析

针对FCC汽油降烯烃后辛烷值低影响企业高辛烷值汽油调和的问题,室内评价了不同FCC汽油馏分对WK-602型辛烷值改进剂的感受性及与其它调和组分的相互作用。结果表明WK-602可有效提高汽油辛烷值,基础汽油的辛烷值愈低作用效果愈明显,添加量每增加0.5%,RON值可提高0.7~1个单位,与其它高辛烷值组分/添加剂的互溶性好,无消极作用;工业放大应用显示WK-602与高辛烷值组分/添加剂混合分散均匀,调和生产的97#车用汽油指标满足质量标准要求。应用WK-602辛烷值改进剂调和生产93#、97#汽油产品的经济效益良好。     

汽油辛烷值机安装、调试方法的研究

汽油辛烷值发动机引法法测定法是目前唯一可靠的辛烷值测定法。本文对马达法和研究法合二为一的汽油辛烷值机的安装、调试、样品测定方法进行了详细的描述、探讨和改进,提高发动机引擎法测定汽油辛烷值的可靠性、准确性和精密性,为炼油工业提供准确的数据。     

探讨敲击检测技术在复合材料无损检测中的应用

本文根据纤维增强复合材料的特性,列出了损伤的主要类型和产生原因;对适用于复合材料制品的无损检测敲击技术进行探讨;对敲击技术的基本原理、方法分类、适用范围进行介绍;对传统敲击法和数字敲击法进行比较;总结敲击法的未来发展状况。     

辛烷值试验机的捡修

辛烷值试验机是测定汽油的马达法和研究法辛烷值的大型专用设备.本文重点介绍了美国ASTM-CFR辛烷值试验机定期拆机检修的整个过程和操作步骤,介绍了设备检修的实践经验和注意事项.     

基因敲除技术研究进展

基因敲除技术是研究功能基因作用的重要方法,是后基因组时代的重要研究内容.从基因敲除的细胞基础、基因敲除载体的构建及发生同源重组干细胞的筛选、基因敲除动物模型的建立、基因敲除与基因拯救、国内基因敲除技术的研究现状等方面概括了基因敲除技术的研究进展和该技术目前存在的主要问题.     

Safe operating conditions determination for stationary SI gas engines

Knock is a major problem when running combined heat and power (CHP) gas engines because of the variation in the network natural gas composition. A curative solution is widely applied, using an accelerometer to detect knock when it occurs. The engine load is then reduced until knock disappears. The present paper deals with a knock preventive device. It is based on the knock prediction following the engine operating conditions and the fuel gas methane number, and it acts on the engine load before knock happens. A state of the art about knock prediction models is carried out. The maximum of the knock criterion is selected as knock risk estimator, and a limit value above which knock may occur is defined. The estimator is calculated using a two-zone thermodynamic model. This model is specifically based on existing formulas for the calculation of the combustion progress, modified to integrate the effect of the methane number. A chemical kinetic model with 53 species and 325 equilibrium reactions is used to calculate unburned and burned gases composition. The different parameters of the model are fitted with a least squares method from an experimental data base. Errors less than 8% are achieved. The knock risks predicted for various natural gases and operating conditions are in agreement with previous work. Nevertheless, the knock risk estimator is overestimated for natural gases with high concentrations of inert gases such as nitrogen and carbon dioxide. The definition of a methane number limit based on the engine manufacturer's recommendation is then required to eliminate unwarranted alerts. Safe operating conditions are thus calculated and gathered in the form of a map. This map, combined with the real time measurement of the fuel gas methane number, can be integrated to the control device of the CHP engine in order to guarantee a safe running towards fuel gas quality variation.     

Preventive knock protection technique for stationary SI engines fuelled by natural gas

In a combined heat and power (CHP) plant, spark ignition engines must operate at their maximum power to reduce the pay back time. Because of environmental and economic concerns, engines are set with high compression ratios. Consequently, optimal operating conditions are generally very close to those of knock occurrence and heavy knock can severely damage the engine piston.There are two main protection techniques: the curative one commonly used by engine manufacturers and well documented in the literature and the preventive one based on a knock prediction according to the quality of the supplied gas. The indicator used to describe gas quality is the methane number (MN). The methane number requirement (MNR) of the engine is defined, for an engine set (spark advance, air-fuel ratio, and load), as the minimum value of MN above which knock free operation is ensured. To prevent knock occurrence, it is necessary to adapt the engine tuning according to variable gas composition. The objective of the present work is to validate the concept of knock preventive protection. First, a prediction of MNR according to engine settings (ES) is computed through a combustion simulator composed of a thermodynamic 2-zone model. Predicted MNR are compared to experimental results performed on a single-cylinder SI gas engine and show good agreement with numerical results (uncertainty below 1 point). Then, the combustion simulator is used to generate a protection mapping. At last, the knock preventive protection was successfully tested.     

Development of an autoignition submodel for natural gas engines

This paper describes a new autoignition submodel for engine modeling codes. This submodel does not require extensive computational resources and is easily portable to various computational environments. It also considers variation of natural gas composition due to propane addition. Computation results show that the knock occurrence crank angle can be predicted within 2° CA when the model is coupled to a zero-dimensional engine model, which was also developed for the present work. The results with the model incorporated into a multi-dimensional model (KIVA) are also promising. KIVA was able to predict if the engine was going to knock or not and also gave correct trends in the knock intensity.     

Knock rating of gaseous fuels in a single cylinder spark ignition engine

This paper presents the determination of knock rating of gaseous fuels in a single cylinder engine. The first part of the work deals with an application of a standard method for the knock rating of gaseous fuels. The Service Methane Number (SMN) is compared with the standard Methane Number (MN) calculated from the standard AVL software METHANE (which corresponds to the MN measured on a Cooperative Fuel Research engine). Then, in the second part, the ‘mechanical’ resistance to knock of our engine is highlighted by means of the Methane Number Requirement (MNR). A single cylinder LISTER PETTER engine was modified to run as a spark ignition engine with a fixed compression ratio and an adjustable spark advance. Effects of engine settings on the MNR are deduced from experimental data and compared extensively with previous studies. Using the above, it is then possible to adapt the engine settings for optimal knock control and performances. The error on the SMN and MNR stands beneath ±2 MN units over the gases and engine settings considered.     

Stratification of fuel for better engine performance

The concept of fuel stratification has been proposed and applied to a four-valve port injection spark ignition engine. In this engine, two different fuels or fuel components are admitted through two separate inlet ports and stratified into two regions laterally by strong tumble flows. Each stratified region has a spark plug to control the ignition. This engine can operate in the stratified lean-burn mode at part loads when fuel is supplied only to one of the inlet ports. While at high load operation, an improved fuel economy and higher power output are also expected through increased anti-knock features by taking advantage of the superior characteristics of different fuel or fuel components. This is achieved by igniting the lower RON (research octane number) fuel first and leaving the higher RON fuel in the end gas region. In this paper, knock limits of homogenous and different fuel stratification combustion modes at high loads were investigated experimentally. Primary reference fuels (PRF), iso-octane and n-heptane, were used to simulate three fuels of different RON: RON90, RON95 and RON100. The research results show that with stratified fuel components of low and high octane numbers, the knock limit, as defined by the minimum spark advance for knocking combustion, was extended apparently when the lower RON fuel was ignited first. In addition, the knock limit could also be extended by increasing the amount of higher RON fuel. However, igniting first the lower RON fuel in the fuel stratification combustion mode produced little improvement in anti-knock behaviour over the homogeneous combustion of the mixture of those two stratified fuels with an average RON.     

EVAC/玻纤/陶瓷/铝合金复合材料缺陷的敲击检测方法

针对乙烯–乙酸乙烯酯塑料(EVAC)/玻璃纤维/陶瓷/铝合金复合材料在生产过程中出现的脱粘缺陷,开展了缺陷试样制备方法研究和多通道自动敲击检测工艺研究。采用两种方法制备缺陷试样,经过试验对比分析,发现热压罐真空辅助成型方法制备的缺陷试样更适合采用敲击检测方法进行检测。通过对缺陷试样的敲击试验,得出提高敲击通道数和频率会提高检测速度,且对检测结果无影响,提高扫查间距虽然可以明显提高检测速度,但对检测结果会有不利影响。试验结果表明,采用敲击检测方法可以检出该复合材料中存在的脱粘缺陷。     

Self-ignition ahead of the flame front in piston spark-ignition engines

The hypothesis that engine knock is a result of competition of two types of chemical reaction—frontal frontal and volumetric—is put forward. A mathematical model for mixture self-ignition ahead of the flame front in an internal-combustion spark-ignition engine is constructed. The operation process was calculated numerically with variation of the ignition angle, the degree of compression, and the rotation frequency of the crankshaft. A critical condition for the occurrence of engine knock is obtained by approximate analytical solution of the problem. Comparison of theoretical results for ten engine parameters and operation with experimental data of different authors confirms the validity of the proposed hypothesis on the occurrence of engine knock. Translated from Fizika Goreniya i Vzryva, Vol. 33, No. 6, pp. 3–13, November–December, 1997.