Mechanism analysis of solvent selectivity and energy-saving optimization in vapor recompression-assisted extractive distillation for separation of binary azeotrope

Octane and p-xylene are common components in crude gasoline, so their separation process is very important in petroleum industry. The azeotrope and near azeotrope are often separated by extractive distillation in industry, which can realize the recovery and utilization of resources. In this work, the vapor–liquid equilibrium experiment was used to obtain the vapor–liquid equilibrium properties of the difficult separation system, and on this basis, the solvent extraction mechanism was studied. The mechanism of solvent separation plays a guiding role in selecting suitable solvents for industrial separation. The interaction energy, bond length and charge density distribution of p-xylene with solvent are calculated by quantum chemistry method. The quantum chemistry calculation results and experiment results showed that N-formylmorpholine is the best solvent among the alternative solvents in the work. This work provides an effective and complete solvent screening process from phase equilibrium experiments to quantum chemical calculation. An extractive distillation simulation process with N-formylmorpholine as solvent is designed to separate octane and p-xylene. In addition, the feasibility and effectiveness of the intensified vapor recompression assisted extraction distillation are also discussed. In the extractive distillation process, the vapor recompression-assisted extraction distillation process is globally optimal. Compared with basic process, the total annual cost can be reduced by 43.2%. This study provides theoretical guidance for extractive distillation separation technology and solvent selection.     

油价临界点理论、方法及应用初探

提出油价临界点概念,解决如何在波动油价下,选择具有一定规模的石油项目。通过油价临界点的应用,石油公司能够准确判断石油项目的投资机会,科学调整石油项目的经营规模,合理把握国际油价波动的影响,为提高项目抗风险能力提供科学依据。     

A new bubbling extraction tower: Toward liquid–liquid solvent extraction at large aqueous‐to‐oil phase ratios

Enrichment and recovery of valuable components in industrial waste waters by traditional liquid–liquid solvent extraction is not economic due to extremely low concentrations of those targets. Large‐phase‐ratio extraction exhibits potential advantages for recovery of small quantities of target components from large volume of aqueous solutions. A novel bubbling extraction tower is proposed toward performing solvent extraction at large aqueous‐to‐oil phase ratios in this work. Organic extractants were covered onto surface of gas bubbles to form a layer of organic liquid membrane and the dispersed organic phase in tower could be small enough. The target components are extracted from aqueous feed solution onto the surface of the bubbles, and the enrichment ratios could be extremely high. We develop a feasible methodology to calculate tower height and operation phase ratios of the bubbling extraction tower, which is essential for future industrial scale‐up. Experimental results in pilot test are highly consistent with calculations. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3889–3897, 2015     

三元水盐体系冰点和共晶点的测定、相图表达及计算

针对Na⁺//Cl^-,NO₃^--H₂O、Na⁺//Cl^-,SO₄^2--H₂O和Na⁺,K⁺//Cl^--H₂O 3个三元水盐体系,测定了不同组成时溶液的冰点、共晶点以及降温过程的析盐规律,绘制出三元体系温度-组成立体相图。结果表明：三元体系的冰点、共晶点、相关系与组成可用三棱柱表达,3个三元水盐体系在共晶点温度下均无复盐存在,各含有1个两盐与冰的共晶点,3条单盐与冰或盐盐的共晶线,1个冰和两个单盐结晶区;用三元体系温度-组成立体相图能更直观地表达三元水盐体系的结晶区、冰点、共晶点和溶液组成的关系,可以判断溶液降温过程中的盐或冰的析出类型、温度;同时建立了冰点经验公式,应用经验公式和过量吉布斯自由能模型预测三元体系的冰点和共晶点,计算值和实验值吻合良好。     

密闭容器内失控反应超压的数学建模及其在压力泄放中的应用

安全泄放是在失控条件下降低反应体系风险最为经济有效的技术措施之一。研究压力的数学模型既可以为泄放计算提供必要的参数,又可以让工程师深入了解样品在容器内的压力变化情况,设计出更可靠的泄放系统,并且在减少实验量的同时,还可以计算不同装载率下的泄放面积。以20% DTBP（过氧化二叔丁基）的ARC（加速度量热仪）测试为标准,结合理论推导得到了绝热条件下密闭容器中失控反应超压的数学模型,并将绝热修正后的压力测试曲线与模型模拟的压力曲线对比,验证了模型的正确性。最后,将模型的压力模拟数据应用于20% DTBP的泄放计算中,结合Leung方法,得到了不同装载率下的泄放面积,发现在装载率为20%时,泄放面积达到最大为0.0035 m²。研究结果表明建立的压力数学模型是正确可靠的,并且该模型能较好地应用于压力泄放的计算中。     

燃烧加热污染空气对超燃冲压发动机性能影响研究

针对燃烧加热地面试验设备存在的工质污染问题,采用数值模拟方法研究了燃烧加热污染空气对氢燃料超燃冲压发动机性能的影响。以飞行马赫数Ma=6.5,当量油气比ER=0.6为计算基准状态,分别对纯净空气和污染空气来流下氢燃料超燃冲压发动机的整机流场和性能进行了对比计算分析。燃烧化学反应模拟采用了改进的H₂/O₂七组分八方程模型,湍流模型为标准的 k-ε模型,并采用直连式燃烧室试验数据进行了数值方法的验证。研究结果表明:(1)相对于纯净空气来流,污染空气来流下的超燃冲压发动机推力和比冲均有所下降。(2)采用酒精燃烧加热器的前提下,来流参数匹配静温、静压、马赫数时,发动机性能与纯净空气来流下的结果最为接近,而匹配总温、总压、马赫数时相差最大。(3)来流参数匹配总焓、静压、马赫数的前提下,采用氢燃烧加热器时发动机性能与纯净空气来流下的结果最为接近,而采用甲烷燃烧加热器时相差最大。      

Al_2Sr和Mg2sr相结构稳定性与弹性性能的第一原理计算

采用基于密度泛函理论的CASTEP和DMOL程序软件包,计算了Mg_(17)Al_(12),Al_2Sr和Mg_2Sr柏的结构稳定性、弹性性能和电子结构.合金形成热和结合能的计算结果显示,Al_2Sr具有最强的合金化形成能力和结构稳定性.Gibbs自由能的计算结果表明,随着温度的升高,Mg_(17)Al_(12),Al_2Sr和Mg_2Sr的结构稳定性发生了变化,在实际工作温度高于423 K以上时,Al_2Sr的结构稳定性最好,Sr合金化Mg-Al基合金形成Al_2Sr有利于提高镁合金的高温抗蠕变性能.体模量(B)、弹性各向异性系数(A)、Young's模量(E)、剪切模量(G)和Poisson比(v)的计算结果表明,Mg2Sr为延性相,而Mg_(17)Al_(12)和Al_2Sr为脆性相,Mg_2Sr的塑性最好.态密度和Mulliken电子占据数的计算结果表明,Al_2Sr结构最稳定的原因主要源于体系存在强烈的共价键作用,而Mg_(17)Al_(12)结构隐定性优于Mg_2Sr是体系中离子键与共价键共同作用的结果.     

无底柱分段崩落法三级矿量计算方法的探讨

结合无底柱分段崩落法采矿工艺,探讨了三级矿量的计算方法,并以工程实例进行了应用计算。     

不同钕铁硼磁体对兆瓦级风力发电机空载磁路的影响

本文研究了不同SH标号NdFeB永磁体对一种兆瓦级风力发电机空载性能的影响。在不改变发电机结构尺寸的情况下,气隙磁密、定子齿磁密和定子轭磁密随磁体SH标号的增高而线性增加,但增加的幅度小于剩磁增加的幅度;工作点数值虽有极微小增加,但基本保持不变;同时输出电压随着磁体SH标号的增高而增加。若通过改变永磁体的用量达到输出电压为额定电压的目的,高标号永磁体的用量体积随之减少。     

天然气压气站内腐蚀挂片监测管道内腐蚀

使用腐蚀挂片可以对管道内腐蚀进行较为全面和准确的监测.本文基于腐蚀挂片在天然气压气站管道的内腐蚀监测应用,详细地介绍了腐蚀挂片的类型、结构、选用、使用步骤和腐蚀速率的计算.