优化转化炉水碳比提高甲醇装置经济效益

转化炉水碳比是转化制备合成气的关键工艺参数 ,国内和国外都一直朝着低水碳比运行方面努力 ,本文通过对 10t甲醇装置的实际工艺分析和工业运行 ,取得了低水碳比的工业数据和经验 ,体现了低水碳比运行的经济优势     

水碳比对转化反应的影响分析

基于天然气转化工艺的技术原理，介绍了水碳比对转化反应的影响。主要从甲烷蒸汽转化反应热力学分析和低水碳比对转化反应的影响两个方向分析水碳比对转化反应的影响。经过分析过程获取最佳水碳比，进而将其应用于某公司天然气转化工艺生产实践，确认最佳水碳比具有较高可行性。     

轻质烃蒸汽转化热力学最小水碳比

根据热力学原理提出最小水碳比的数学模型，并应用数值计算方法，准确计算出各种轻质烃在不同压力和温度下蒸汽转化热力学最小水碳比，为采取低水碳比操作轻质烃蒸汽转化提供了热力学基础数据。     

水碳比控制系统的改进措施

分析了转化触媒析炭的原因,提出了水碳比控制系统由单闭环控制系统改为双闭环控制系统,改造后有效避免了水碳比过低而造成转化触媒析炭。     

基于神经网络-遗传算法优化制氢工艺水碳比

根据某炼油厂制氢车间的生产数据,用人工神经网络(ANN)的反向传播(BP)算法建立了制氢装置转化生产中的水碳比神经网络预测模型,生产数据的检验表明,ANN方法能准确地关联和预报制氢装置转化生产中的水碳比,水碳比预测平均相对误差为2．83％;该神经网络预测模型用遗传算法优化并得到了最佳制氢工艺操作条件。     

轻质烃蒸汽化热力学最小水碳比

根据热力学原理提出最小水碳比的数学模型，并应用数值计算方法，准确计算出各种轻质烃在不压力和温度下蒸汽转化热力学最小水碳比，为采取低水碳比操作轻质烃蒸汽提供了热力学基础数据。     

水碳反应比及其应用探讨

水碳比是烃类蒸汽转化制氢装置的一个控制参数,而本文所提出的水碳反应比则是评价制氢装置运转水平的一个重要参数,在生产实践中,它有多种用途.给出水碳反应比的定义,同时介绍其计算方法,并列举了数项水碳反应比的典型应用实例.     

天然气蒸汽转化制氢装置水碳比控制及联锁设计优化探讨

在天然气蒸汽转化制氢单元中,水碳比控制和联锁设计是非常重要的环节.结合以往天然气转化制氢装置工程设计经验,提出水碳比控制及联锁的优化方案,以满足改进后控制方案的安全性和可操作性,进而实现水碳比的平稳控制,确保装置的正常连续生产.     

根据反应机理确定转化炉水碳比及其控制方案

对于以天然气为原料,采用ICI工艺的甲醇装置,选择合理的转化炉进料水碳比对整个工艺非常重要,而确定水碳比必须要综合考虑转化炉内的各种反应。本文简述根据转化炉内的反应机理来确定进料水碳比及其控制方案。1根据转化炉内化学反应的机理确定水碳比1.1转化反应机理脱硫后的天然气进气(甲烷含量大于97%)与2 940 kPa的蒸汽混合后,进入一段转化炉进     

甲烷转化水碳比控制在ECS100P DCS的实现

针对甲烷转化中存在多股原料气且甲烷含量波动大的情况,分析了影响甲烷转化之水碳比的因素,设计水碳比比值控制方案时引入原料气中甲烷含量的分析信号,在ECS100P DCS中实现比值控制方案并应用于生产控制。     

联产三聚氰胺对尿素装置的影响

大型尿素装置联产三聚氰胺后,因运行状况发生了改变,存在解吸水解系统超负荷运行、系统水平衡被破坏、水碳比升高、操作弹性降低、难度增大及消耗增加等问题,需在实际运行中探索解决的方法。     

合成氨预转化系统的改造

采用预转化工艺,解决原料气中高碳烃含量高的问题。初次尝试后,达到了提高热反应效率、降低水碳比、降低能耗、解决超温问题、延长盘管使用寿命的目的。     

Structural properties of water around uncharged and charged carbon nanotubes

Studying the structural properties of water molecules around the carbon nanotubes is very important in a wide variety of carbon nanotubes applications. We studied the number of hydrogen bonds, oxygen and hydrogen density distributions, and water orientation around carbon nanotubes. The water density distribution for all carbon nanotubes was observed to have the same feature. In water-carbon nanotubes interface, a high-density region of water molecules exists around carbon nanotubes. The results reveal that the water orientation around carbon nanotubes is roughly dependent on carbon nanotubes surface charge. The water molecules in close distances to carbon nanotubes were found to make an HOH plane nearly perpendicular to the water-carbon nanotubes interface for carbon nanotubes with negative surface charge. For uncharged carbon nanotubes and carbon nanotubes with positive surface charge, the HOH plane was in tangential orientation with water-carbon nanotubes interface. There was also a significant reduction in hydrogen bond of water region around carbon nanotubes as compared with hydrogen bond in bulk water. This reduction was very obvious for carbon nanotubes with positive surface charge. In addition, the calculation of dynamic properties of water molecules in water-CNT interface revealed that there is a direct relation between the number of Hbonds and selfdiffusion coefficient of water molecules.     

悬浮床加氢脱硫尾气水蒸气转化制氢热力学

以悬浮床加氢脱硫尾气为水蒸气转化制氢原料,采用改进的原子序数矩阵法构建了包含6个独立反应的化学反应体系。分别考察各个独立反应在不同反应温度下,标准摩尔反应焓、吉布斯自由能变及平衡常数的变化规律;借助HYSYS流程模拟软件中的GIBBS反应器,研究反应器出口温度、反应压力及水碳物质的量之比对产物平衡组成的影响。热力学研究结果表明：烷烃碳数越高,水蒸气转化反应的平衡常数、吉布斯自由能变和标准摩尔焓对温度的敏感性越高,达到相同转化效果所需的反应温度越低。HYSYS模拟确定该体系下最适宜的反应条件为反应器出口温度700℃、反应压力100kPa、水碳物质的量之比4。     

Chlorination kinetics of pyrite mineral in two Turkish lignites

The kinetics of the chlorination of pyrite in two Turkish lignites in water and water-carbon tetrachloride media at ambient pressure ( 610 mm Hg) are investigated. The effects of speed of stirring (5–20 s⁻¹), particle size (74–88, 150–180 and 250–425 μm), temperature (13–70°C) and reaction time (0–18 000 s) were studied. The experimental data were analyzed on the basis of the unreacted shrinking core model. The fine pyrite particles are assumed to be embedded inside the coal particles. The rate-controlling step was found to be diffusion of chlorine through the ash (the coal matrix). The activation energies were calculated as 25.1 kJ mol⁻¹ for Dada i coal in water medium and 25.0 kJ mol⁻¹ for Mengen coal in water-carbon tetrachloride medium.     

泡载分离器的研究——泡载分离器内微气泡的分布规律

利用H_2O-CO_2体系,对溶气法产生气泡的分布规律进行考察。实验结果发现,微气泡的分布呈非对称拖尾分布。从气液传质、能量转换和气泡动力学的角度,对气泡形成饥理进行分析。提出了描述气泡拖尾分布的Γ函数分布,并讨论其分布函数中参数m的物理意义。     

1kW SOFC-CHP系统用催化燃烧耦合蒸汽重整反应器的实验研究

针对1 kW 固体氧化物燃料电池热电联供(SOFC-CHP)系统开发了集成催化燃烧、换热及蒸汽重整的反应器,搭建了性能评价系统,系统研究了燃烧侧气体组分及工艺参数对该反应器性能的影响规律。实验结果表明:在反应器燃烧侧气体入口温度为300℃、空燃比为10:1、电堆燃料利用率为65%、水碳比为3 的条件下,重整侧转化率达到73.6%,重整尾气中H₂ 含量为67.5%。电堆燃料利用率对重整反应转化效率影响较大,其值大于80%时,采用尾气燃烧的余热回收方式无法有效为蒸汽重整提供所需热量。在150~350℃范围内,降低燃烧侧气体入口温度对重整反应效率影响较小,建议采用尾气先换热再进行催化燃烧的流程设计,保证重整效率的前提下可有效提升系统热效率。空燃比的降低可小幅度提升重整效率,在保证电堆反应温度稳定的前提下,适当降低空燃比可减少空气压缩机的功耗,从而提升整个系统的效率。研究成果对SOFC-CHP 系统的优化和整体效率提升具有指导意义。     

Catalytic carboxylation of fats: Carboxy acids from polyunsaturates

Studies with a palladium chloride-triphenylphosphine catalyst have been extended to the carboxylation of polyunsaturated fats. Linseed, soybean, and safflower oils, acids, and esters were carboxylated catalytically with water-carbon monoxide (4000 psig) at 120–160 C with or without acetone as a solvent. Main products were monocarboxy, 1,3- and 1,4-dicarboxy and tricarboxy acids. Minor products were carbomethoxy esters and disubstituted 2-cyclopentenone. Optimum reaction conditions were determined for the carboxylation of linseed oil and methyl esters by statistically designed experiments. Yields of total carboxy and tricarboxy acids were maximized at low triphenylphosphine and water levels, low temperatures, and high palladium-chloride concentrations. Carboxylated soybean esters were separated by ether extraction of the palladium catalyst from sodium carbonate or hydroxide carboxylate salts. This salt extraction permits catalyst recycling. Presented at the AOCS Spring Meeting, Mexico City, April 1974. Biometrician, North Central Region, USDA. ARS, USDA.     

Potassium-catalyzed steam gasification of petroleum coke for H2 production: Reactivity, selectivity and gas release

Potassium-catalyzed steam gasification of petroleum coke for H₂ production was performed using a laboratory fixed-bed reaction system with an on-line quadruple mass spectrometer. The gasification reactivity, gasification selectivity and gas release for the catalytic gasification were investigated, compared with the non-catalytic gasification. The catalytic gasification could not only effectively promote these reactions (the water-carbon reaction, the water-gas shift reaction and the methane-steam reforming reaction), but also elevate greatly the gasification selectivity towards CO₂ (a high gasification selectivity towards CO₂ meant a high H₂ production). A quantitative calculation method for the gasification selectivity towards CO and CO₂ was proposed to further understand the catalytic behaviors of catalysts. In the case of catalytic gasification, the gasification temperature had opposite effects on the gasification reactivity and the gasification selectivity towards CO₂, suggesting that there existed an optimum gasification temperature (about 750 °C) for H₂ production from the potassium-catalyzed steam gasification of petroleum coke. In addition, petroleum coke could be feasibly utilized as the feedstocks for the catalytic steam gasification to produce gases with high H₂ (55.5-60.4%) and virtually no CH₄ (below 0.1%).     

乙苯脱氢制取苯乙烯反应条件的研究

使用氧化铁系催化剂,研究了乙苯脱氢制取苯乙烯中乙苯转化率和苯乙烯的选择性与温度、进料比的关系.实验证明,乙苯的转化率受温度和进料比的共同影响,在所研究的范围内,苯乙烯的选择性主要受温度影响,选择合适的进料比对提高转化率和选择性至关重要.