新型填料喷雾塔强化吸收甲醇废气的应用

甲醇作为化学工业基础原料和清洁液体燃料,长期接触会引起中毒。为了进一步的工业要求提供参考依据,文中采用了新型填料喷雾塔对含甲醇废气进行强化吸收的实验研究。通过改变液体流量、气体流量、甲醇进口质量浓度和温度单因子参数的方法观察甲醇的去除率和总吸收率,根据分析实验数据可知,当液气比与温度一定时,甲醇去除率和总吸收率随甲醇质量浓度增加而降低;当液气比与甲醇进口质量浓度一定时,两者随温度的升高呈缓慢上升趋势;当温度与液体流量一定时,甲醇去除率随着气体流量的增加而降低,而总吸收率随气体流量增加呈上升趋势;在气体流量一定时,两者都随液体流量的增加而增加。最后通过激光粒度分析仪测试该塔中4种不同高度喷雾液滴粒径分布。     

浆态床甲醇脱水反应特性研究

考察了温度、压力以及液体空速等操作条件对反应过程的影响，同时探讨了惰性溶剂中水含量对甲醇转化率的影响，为浆态床一步法二甲醚合成工艺研究提供基础实验数据，实验结果表明，在所研究的温度范围内，甲醇转化率随温度升高而增加，在低压条件下甲醇转化率随空速的增加单调递减，而在高压下，由于水在浆液中不断积累，不利于甲醇转化，减小体系中水的含量能明显提高甲醇的转化率。     

HZSM-5催化甲醇制丙烯工艺条件的考察

以工业应用的HZSM-5为催化剂,在连续固定床反应器中考察了反应温度和甲醇分压对甲醇制丙烯反应产物的影响,发现当温度大于450℃时,随着温度的升高,甲醇的转化率都能达到99%以上,乙烯和丙烯的总选择性增加,低碳烷烃选择性增加,高碳产物选择性下降;随着甲醇分压降低,甲醇转化率下降,产物丙烯/乙烯质量比(P/E比)增加,丙烯在甲醇分压为33 kPa时达到最高值,而当分压极低时,催化剂快速失活。从转化率、丙烯选择性、P/E比以及低碳烯烃产物选择性等多方面综合考虑,甲醇转化制丙烯的反应温度优选470℃,并建议甲醇分压为33 kPa。     

控温条件下甲醇分子集聚特性的研究

控温条件下采用分子动力学模拟研究甲醇水溶液中甲醇分子的集聚特性,研究发现,甲醇的集聚特性随温度增加而增强。     

甲醇对丙烷/氧气混合气爆炸极限的影响

为探究替代燃料丙烷/甲醇混合气的氧化反应特性,利用爆炸极限开展了甲醇对丙烷/氧气混合气的负温度系数（NTC）响应特性的研究。结果表明：在NTC区域,下拐点的压力随着甲醇摩尔分数的增加而升高,但下拐点的温度几乎保持不变。然而上拐点的温度与压力随着甲醇摩尔分数的增加没有明显变化。整体而言,随着甲醇摩尔分数的增加,丙烷/氧气混合气的NTC区域不断减小并向高压区域移动。对比分析了不同爆炸状态下,即无爆炸、冷焰以及热焰状态,混合气的温度、压力以及主要组分变化,并获得了影响温度变化的主要基元反应。此外,对爆炸极限曲线的NTC区域上、下拐点进行了敏感性分析,确定影响拐点状态的主要基元反应。     

ZSM-5催化剂上的甲醇转化研究

利用固定流化床反应器,考察了甲醇在改性ZSM-5分子筛催化剂上转化过程。实验结果表明:反应温度增加,甲醇转化率上升;乙烯和丙烯碳基选择性随温度增加而增加,且丙烯选择性的增加速率大于乙烯选择性的增加速率;油相产物的碳基选择性随温度增加而降低,而油相中芳烃浓度随温度的增加而增加;芳烃产物主要为C8芳烃,且C6芳烃、C7芳烃、C8芳烃随温度的增加而降低。由于分子筛酸性随温度的增加而变弱,降低了丙烯的氢转移反应速率,故丙烷/丙烯比随温度的增加而降低。     

甲醇溶析铝酸钠制备氢氧化铝

以甲醇水溶液分解铝酸钠晶体,采用溶析法制备了超细氢氧化铝. 考察了30℃下氧化铝、氧化钠溶解度随甲醇质量分数的变化规律,研究了甲醇质量分数和反应温度对水合铝酸钠晶体分解工艺的影响,用XRD, IR, SEM及粒度分析、纯度分析等手段对制备的氢氧化铝产品进行了表征. 结果表明,随着溶剂中甲醇质量分数的增加,氧化铝和氧化钠溶解度均下降,但氧化铝下降幅度更大;铝酸钠溶液分子比(氧化钠/氧化铝摩尔比)先增加后减小,到甲醇质量分数为0.8左右时达到最大值. 30℃下水合铝酸钠晶体与甲醇质量分数为0.5~0.8的甲醇-水混合溶剂反应1~3 h,铝酸钠分解率可达到80%~90%,温度升高,分解率略有下降. 甲醇溶析得到的氢氧化铝30℃下为拜耳石型,温度升高逐渐变为三水铝石型,红外光谱完整. 产品形貌规则,为高纯薄片状超细氢氧化铝,平均厚度100 nm,平均粒径1.05 mm.     

甲醇制低碳烯烃反应体系的热力学计算与分析

采用原子矩阵法确定了甲醇制低碳烯烃独立的反应数,采用Gibbs自由能最小化方法,建立了计算烯烃产物之间平衡关系的数学模型,简化了计算过程。计算了甲醇制低碳烯烃各独立反应的Gibbs自由能及烯烃产物之间的平衡关系。热力学分析表明,甲醇制低碳烯烃反应主要为动力学控制,提高反应温度、降低反应压力和加水有利于乙烯平衡组成增加和乙烯与丙烯总平衡组成的增加,丙烯平衡组成随温度、压力变化存在最大值。计算数据与文献值比较表明,该法计算结果可靠,对甲醇制低碳烯烃的实验室研究及工业化生产有指导意义。     

近临界条件下乙烯水合物在甲醇水溶液中的生成行为研究

研究了近临界条件下乙烯水合物在甲醇水溶液中的生成行为,考察了温度、压力以及甲醇浓度对乙烯水合物生成行为的影响。实验结果表明在乙烯的近临界条件下,P-t曲线为一光滑的曲线,不易明确区分溶解阶段、成核阶段和生长阶段;随着初始压力的升高,水合物生成速率加快,且始末压差增大,水合物生成量增多;随着温度的降低,过冷度增大,促进水合物生长,压力下降速率增加,水合物生成量增多;甲醇水溶液浓度的增加,抑制了乙烯水合物的生成。     

XNC-98催化剂甲醇合成本征动力学

在等温积分反应器中研究了XNC-98催化剂上甲醇合成反应本征动力学.实验压力为4~8MPa,空速7000~13000h-1,反应温度200~260℃.实验采用粒度为0.154~0.198mm的细颗粒催化剂.选取以各组分逸度表示的CO、CO2加氢合成甲醇的Langmuir-Hinshelwood本征动力学模型.采用正交实验设计,实验测定了25组数据,用全局通用算法结合马夸特算法确定动力学模型参数.残差分析和统计检验表明,动力学模型是适宜的.随温度升高,反应器出口甲醇浓度、CO和CO2转化率先增加后降低,在4~8MPa下,230~245℃为较佳反应温度范围:随着反应压力的提高,反应器出口甲醇浓度、CO和CO2转化率都有显著增加,提高反应压力能够有效提高反应器的生产能力.     

对二甲苯在醋酸中扩散系数的测定

为了提供精对苯二甲酸（PTA）生产过程中相关体系的扩散系数,利用金属膜池并用氯化钾水溶液标定了膜池常数。用已有文献值的乙酸水溶液验证了装置的可靠性。测定了298.15-323.15K不同温度下对二甲苯在醋酸中的积分扩散系数,还分别给出了微分扩散系数与对二甲苯浓度的关联式。结果表明在相同温度下对二甲苯在醋酸中的扩散系数随着对二甲苯浓度的增加而减小,在同一浓度下随着温度的升高而增加。     

邻二甲苯在醋酸中扩散系数的测定

利用金属膜池并用氯化钾水溶液标定了膜池常数。用已有可靠文献值的乙酸水溶液验证了装置的可靠性。测定了298．15～323．15K不同温度下邻二甲苯在醋酸中的积分扩散系数,还分别给出了微分扩散系数与邻二甲苯浓度的关联式。结果表明在相同温度下邻二甲苯在醋酸中的扩散系数随着邻二甲苯浓度的增加而减小,在同一浓度下随着温度的升高而增加。     

Influence of Tribochemical Reaction Products on Friction and Wear of Silicon Nitride at Elevated Temperatures in Reactive Environments

Friction coefficients and wear rates of hot-pressed Si₃N₄ have been measured in a ball-on-flat linear-sliding geometry at temperatures ranging from room temperature to 1273 K in Ar and air containing up to 63% H₂O. In inert environments, the friction coefficients (ranging between 0.6 and 0.7) are independent of temperature, and wear rates increase with temperature. In oxidizing environments, the friction and wear are reduced by the presence of tribochemical reaction products. Friction coefficients and wear rates are lowered when the wear debris spontaneously forms into rolls, oriented perpendicular to the direction of relative motion, at high H₂O levels in the temperature range of 873 to 1073 K.     

Physicochemical properties of aqueous solutions of sodium glycinate in the non-precipitation regime from 298.15 to 343.15 K

The physicochemical properties, including the density, viscosity, and refractive index of aqueous solutions of sodium glycinate as a solvent for CO2 absorption in the non-precipitation regime were measured under the wide temperature range of 298.15 to 343.15 K. The concentration of the sodium glycinate in an aqueous form in the non-precipitation regime was identified up to 2.0 mol·L?1. The coefficients of thermal expansion values were estimated from measured density data. It was found that, the densities, viscosities and refractive indices of the aqueous sodium glycinate decrease with an increase in temperature, whereas with increasing sodium glycinate concentration in the solution, all three properties increase. Thermal expansion coefficients slightly increase with rising temperature and concentration. The measured values of density, viscosity and refractive index were correlated as a function of temperature by using the least squares method. The predicted data obtained from correlation equations for all measured properties were in fairly good agreement with the experimental data.     

Physical behaviour of oil shale at various temperatures and compressive loads: 1. Free thermal expansion

The effects of grade and specimen orientation on the free thermal expansion of oil shale were investigated. The expansion was found to increase with the grade of the specimen and to be dependent on orientation. The change in heating rate from 1.0 K min⁻¹ to 3.5 K min⁻¹ had little effect on the expansion of oil shale. It was found that many of the oil shale specimens would settle under their own weight once kerogen left the oil shale. The thermal expansion coefficients in the temperature range 373–473 K were determined to be little affected by increases in grade. A polynomial correlation of expansion versus grade and temperature in the temperature range 298–698 K is presented. The behaviour at temperature up to 1000–4000 K was also investigated.     

正丁烷和丁烯-1在不同Si/Al比ZSM-5分子筛上的吸附和扩散行为

以应用于烯烃催化裂解工艺中的具有独特择形性和酸性的ZSM-5分子筛为研究对象,采用重力分析仪在275, 288及300 K下对碳四烃(以正丁烷和丁烯-1为代表)在不同硅/铝比ZSM-5分子筛内的吸附和扩散行为进行了研究. 建立了正丁烷和丁烯-1在ZSM-5分子筛上的双朗格缪尔吸附模型. 同时,运用Fick扩散模型关联得到了正丁烷及丁烯-1在ZSM-5分子筛内的扩散系数. 结果表明,正丁烷及丁烯-1在ZSM-5分子筛内的扩散属于晶体扩散,二者的扩散系数在10-14 m2/s数量级,正丁烷的扩散速率大于丁烯-1. 正丁烷与丁烯-1在ZSM-5分子筛内的扩散速率均随温度的增加而增加,随着体系平衡压力的增加先增加后减小,而且二者的扩散系数随样品硅/铝比的增加而增加. 研究结果为碳四烃催化裂解工艺提供了相关的基础工程数据.     

高压乙醇中的无限稀释扩散系数:实验测定与模型评价

The infinite diffusion coefficients of benzene, toluene, naphthalene, pyridine and p-nitroaniline in ethanol were measured by Taylor dispersion technique under 318-473 K and 0-16 MPa. The measurement accuracy of the established apparatus was first checked. The measured diffusion coefficient of the five organic solutes in ethanol did not change with pressure at low temperature, but it was significantly reduced with pressure increase when the temperature is higher than 373 K. Of the correlations available for polar solvents, the modified Wilke-Chang equation, the Yang-Zhang equation as well as the He-Yu equation were used to calculate the infinite diffusion coefficient. At low temperature,the three equations all agreed well with experimental results for both polar and non-polar solutes.However, the prediction accuracy was decreased sharply when the temperature was higher than 373 K,where the association factor of the solvent was varied with temperature as well as pressure.     

Measurement and thermodynamic modeling of partition coefficients in N,N-dimethylacetamide-water-carbon dioxide system

The partition coefficients of N,N-dimethylacetamide (N,N-DMA) between the water and the supercritical and near-critical carbon dioxide (CO₂) phases were measured in the temperature range of 298.15-328.15 K and the pressure range of 8.3-24.1 MPa. The measurements were carried out in a 56 ml vessel by contacting the carbon dioxide and the aqueous phases. The partition coefficients of N,N-DMA increased from 0.05 to 0.150 with increasing pressure at a constant temperature and increased with temperature at a constant density. The bubble point pressures of N,N-DMA-CO₂ mixtures were measured at 298.15 K, 308.15 K and 318.15 K and were found to increase with increasing mole fraction of CO₂. The partition coefficients were modeled using the Peng-Robinson Equation of State (PREOS) combined with modified van der Waals mixing rule. The binary interaction parameters for the CO₂-H₂O pair were taken from the literature and were regressed for CO₂-N,N-DMA and H₂O-N,N-DMA pairs by fitting partition coefficients data. The binary interaction parameter for CO₂-N,N-DMA pair was found to depend linearly on temperature. The bubble point pressures of N,N-DMA and CO₂ were also measured and could be predicted fairly well using the regressed binary interaction parameters.     

Thermal Expansion of Melts and Glasses in the As–Se System

The bulk thermal expansion coefficients of glasses and melts in the As–Se system are measured in the temperature range 298–1200 K. In glass-forming melts containing 40–60 mol % As, an increase in the density is found at temperatures above 1000 K, which is assumed to be associated with changes in the structure and character of the chemical bonding.     

PBX9501热感度、热膨胀及力学性能的分子动力学模拟

采用分子动力学模拟研究了不同温度和压强条件下PBX9501炸药的热感度、热膨胀和力学性能。通过体系中各组分最大引发键键长的变化判断温度对其热感度的影响;预测了PBX9501体系在不同温度下的热膨胀系数;采用静态力学理论分析其力学性能随温度和压强的变化。结果表明,在295~450K,随温度的升高,PBX9501炸药的敏感性增大,且在375K时其引发键的最大键长显著增大;热膨胀系数随温度升高而减小;随温度升高其脆性越明显,随压强的增加其韧性越好。