微波处理后石油焦水蒸气气化特性的研究

采用热天平考察了1 000~1 150 ℃、30%~100%水蒸气分压下微波处理后石油焦气化动力学特性,并采用四种动力学模型对气化反应速率曲线进行了拟合。结果表明,微波处理后石油焦水蒸气气化反应速率随着微波照射时间、功率、温度的减小而增加,随着水蒸气分压的增加而增加;微波处理后石油焦在1 100 ℃时水蒸气气化反应速率随着转化率的增加先增加后减小,在转化率为20%左右出现最大值,且不随微波处理条件和水蒸气分压的变化而改变,但随着气化温度的升高气化反应速率最大值提前出现。正态分布函数模型能够准确的拟合不同温度下微波处理后石油焦水蒸气气化反应速率随转化率的变化,相关系数均在0.97以上。     

Determination of Sulfur in Petroleum Coke Combining Closed Vessel Microwave-Induced Combustion and Inductively Coupled Plasma-Optical Emission Spectrometry

Abstract

A new procedure based on closed vessel Microwave-Induced Combustion (MIC) technique is proposed for the decomposition of petroleum coke and further determination of sulfur by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). The procedure is based on sample ignition by microwave radiation using closed quartz vessels pressurized with oxygen and use of NH₄NO₃ as an ignition aid. The nature and concentration of absorbing/refluxing solution were studied, as well as the operational parameters related to MIC technique. Results were compared with those obtained by conventional wet digestion in closed vessels, certified reference materials (agreement was better than 98%), and also using ion chromatography for S determination.     

甲烷水蒸气重整与甲烷无氧芳构化反应耦合提高Mo/MCM-49催化剂稳定性

甲烷无氧芳构化(MDA)和甲烷水蒸气重整(MSR)的耦合反应可以大幅度提高甲烷无氧芳构化反应的稳定性.单独的甲烷无氧芳构化反应失活较快,甲烷转化率从0.5 h的14.5%很快下降至15 h的3.5%.而采用联合MSR/MDA反应体系,甲烷的转化率从12.5 h的11.5%非常缓慢地下降至60 h后的6.5%.MSR反应原位生成的CO和H2能降低反应中生成的CHr物种数量,减少催化剂上积炭的牛成,进而延长反应时间.MSR反应过程中高比例H2的生成更能有效地减少与B酸相关的积炭的生成,从而更好地抑制反应的失活.     

化学气相沉积金刚石探测器测量软X射线能谱

金刚石具备高热导率、高电阻率、高击穿电场、大的禁带宽度、介电系数小、载流子迁移率高以及抗辐射能力强等特性,可作为已应用于惯性约束聚变(ICF)实验X射线测量的硅与X射线二极管的较好替代品.随着化学气相沉积(CVD)技术的发展,CVD金刚石受到人们越来越多的关注.文中利用拉曼谱仪和X射线衍射仪对1mm×1mm×2mm,1mm×1mm×3mm两种规格CVD金刚石完成品质检测后,完成了CVD金刚石X射线探测器的集成制作,并在8ps激光器和神光III原型装置上开展了探测器时间特性等性能研究.实验结果表明,整个探测器系统前沿响应时间可达60ps,半高全宽可达120ps,与X射线二极管探测系统时间特性一致.在神光Ⅲ原型装置实验中,没有观察到探测器对3ω0激光的响应,说明探测器具有好的抗干扰能力.其测得的温度曲线与软X射线能谱仪测量结果一致,实现了X射线能谱测量的初步应用.     

Effect of physical disturbance on the structure of needle coke

Through different preparation technology, this paper reports that the needle coke is prepared with coal-tar pitch under the effect of magnetic field and ultrasonic cavitation. It studies the effect of physical disturbance on the structure of needle coke. The structure of needle coke is characterized by scanning electron microscope and x-ray diffractometer, and the influence mechanism is analysed. Results showed that the structure and property of needle coke could be effectively improved by magnetic field and ultrasonic cavitations, such as degree of order, degree of graphitization and crystallization. Comparatively speaking, the effect of magnetic field was greater. The graphitization degree of needle coke prepared under the effect of magnetic field is up to 45.35%.     

格尔木渣油加氢反应及生焦行为的研究

选用超低沥青质含量的格尔木渣油（沥青质质量分数：0.32%）作为加氢原料,考察反应条件对加氢反应样品组分性质、胶体稳定性参数（CSP）、生焦性能的影响。结果表明,随着加氢反应温度的升高和反应时间的延长,沥青质和饱和分的含量增加,胶质和芳香分的含量减少;胶体稳定性参数降低,生焦率不断增加;胶质与沥青质的缩合度增加,芳碳率f_A不断增大;金属与杂原子在加氢过程中不断得到脱除,V比Ni更容易脱除、S比N更容易脱除;催化剂表面形成了类似石墨有序结构的炭基物质,使得催化剂的孔结构参数不断减小。在所研究的反应中,当反应温度和时间分别为420℃和5 h时,催化剂的孔结构损害最为严重,出现了较大的微孔分布。     

空间高能离子在纳米级SOI SRAM中引起的单粒子翻转特性及物理机理研究

基于蒙特卡罗方法研究空间高能离子在65—32 nm绝缘体上硅静态随机存取存储器(SOI SRAM)中产生的灵敏区沉积能量谱、单粒子翻转截面和空间错误率特性及内在的物理机理.结果表明:单核能为200 MeV/n的空间离子在60—40 nm厚的灵敏区中产生的能损歧离导致纳米级SOI SRAM在亚线性能量转移阈值区域出现单粒子翻转;宽的二次电子分布导致灵敏区仅能部分收集单个高能离子径迹中的电子-空穴对,致使灵敏区最大和平均沉积能量各下降25%和33.3%,进而引起单粒子翻转概率降低,以及在轨错误率下降约80%.发现俘获带质子直接电离作用导致65 nm SOI SRAM的在轨错误率增大一到两个数量级.     

Fatigue behaviour of coke drum materials under thermal-mechanical cyclic loading

Coke drums are vertical pressure vessels used in the delayed coking process in petroleum refineries. Significant temperature variation during the delayed coking process causes damage in coke drums in the form of bulging and cracking. There were some studies on the fatigue life estimation for the coke drums, but most of them were based on strain-fatigue life curves at constant temperatures, which do not consider simultaneous cyclic temperature and mechanical loading conditions. In this study, a fatigue testing system is successfully developed to allow performing thermal-mechanical fatigue (TMF) test similar to the coke drum loading condition. Two commonly used base and one clad materials of coke drums are then experimentally investigated. In addition, a comparative study between isothermal and TMF lives of these materials is conducted. The experimental findings lead to better understanding of the damage mechanisms occurring in coke drums and more accurate prediction of fatigue life of coke drum materials.     

结焦催化剂上焦炭氢碳比的测定方法

提出了一种测定裂化结焦催化剂上焦碳H/C的方法--酸溶-元素分析法。该方法主要利用HF和HCl将焦碳从催化剂上进行剥离，然后利用元素分析仪测定焦碳中的碳含量和氢含量，从而可以得到结焦催化剂上焦碳的H/C质量比。这种测定方法避免了在测氢过程中催化剂结晶水和吸附水对测定结果的影响，大大提高了催化剂上焦碳H/C的测定精度。     

Fractal Dimensions of Coals and Cokes

Using adsorption data, we get formulas for the calculation of fractal dimensions: log[A_CO2(DP)/A_N2(BET)] = −5.3984(2 −D₁)/2 and log[A_CO2(BET)/A_N2(BET)] = −4.9569(2 −D₂)/2. The fractal dimensions (D) of 27 coals and 2 cokes have been obtained. TheDof coals decreased with the increase of f_aand reached a maximum at H/C equal to 0.66 (orC_dafabout 86%). The fractal dimension is relative to ash and volatiles of coal:D= 2.2237 + 0.6249V_daf+ 0.8863A_d. The relationship betweenDof coal coke and its conversions (X) obeys the following equation:D = aexp(−bX) +c.