C8芳烃异构化催化剂内气相有效扩散系数的计算

针对C₈芳烃异构化反应中二甲苯等6种反应物在催化剂内的扩散过程,建立一种气相有效扩散系数的计算方法。根据此方法计算得到不同反应压力和温度的条件下,C₈芳烃异构化反应体系中6种气相物质在催化剂内扩散的有效扩散系数,验证了方法的可靠性,并讨论了温度和压力对分子扩散系数的影响,结果表明：随着压力增大,气体密度增大,分子间距变小,分子间作用力变大,分子扩散系数减小;而根据分子运动论,随着温度的升高,气体运动速率和扩散速率都会变大,分子扩散系数增大。     

气体分布器对浆态床环流反应器内流体流动特性影响的研究

基于一种浆态床环流反应器冷模试验装置,采用3种不同的气体分布器,考察了分布器结构对环流反应器流体力学特性的影响,为费托合成浆态床反应器及其内构件的设计和放大提供依据。试验结果表明:金属烧结板气体分布器的分布均匀性最好,但容易堵塞,不能满足长期稳定运行的要求。通过对不同开孔方向的两种双环管分布器进行比较,发现开孔向下时,总平均气含率高、气/液(浆)相界比表面积大,更适合应用于浆态床环流反应器。     

采用氙气的鼓泡床流体力学特性研究

Xenon was used as gas phase to investigate the hydrodynamic characteristics in a bubble column. It was found that the flow pattern is mainly in the churn-turbulent flow regime by analysing the relationship between the slip velocity and gas holdup. The influences of operating conditions on the gas holdup and Sauter mean diameter were studied. The experimental results show that the Sauter mean diameter decreases with the increase of energy dissipation rate. A new correlation was developed to predict the Sauter mean diameter with an average error less 15%.     

气升式浆态床外环流反应器内液固连续错流过滤工艺研究

高固含率（r_s）的浆液体系中微细颗粒的高效分离技术是限制浆态床费-托合成技术工业应用的难题之一,将浆态床外环流反应器与膜分离技术在线耦合,基于反应器内独特的流体力学行为和三相分布规律,开发了在线错流过滤技术。以接近真实体系的氮气、柴油和钴催化剂体系为研究对象,系统地研究了浆态床外环流反应器内连续错流过滤规律,考察了表观气速（u_g）、r_s和跨膜压差（ΔP）对分离效果的影响。结果表明：在ΔP为0.45MPa、u_g为0.1m/s、r_s为10%和20%的条件下,滤液稳定渗透通量分别为60 L/(m².h)和17 L/(m².h),此时滤液中颗粒质量浓度均低于5 mg/L,在此条件下膜过滤器可连续稳定运转至少720 min。对比脉冲式反冲洗工艺和单次连续式反冲洗工艺对恢复滤膜通量的影响,结果表明,脉冲式反冲洗工艺能更好地恢复滤膜通量。     

用于浆态床费托合成的错流过滤数学模型的研究进展

分析了浆态床费托合成错流过滤过程中滤膜污染的机理,并分别综述了三相过滤和两相过滤过程中数学模型的研究进展根据阻力不同,将模型分为堵塞阻力模型、滤饼层阻力模型和组合阻力模型.在对现有模型研究总结的基础上,通过对比和分析指出了组合阻力模型是浆态床费托合成错流过滤数学模型研究的方向.     

聚合-分散脉冲筛板萃取塔两相流动特性

A study on two-phase flow characteristics in a coalescence-dispersion pulsed-sieve-plate extraction column of 150mm in diameter was carried out with a working system of 30% tri-butyl-phosphate (TBP) (in kerosene)-nitric acid-water. The influence of operation conditions on the holdup of the dispersed phase was investigated. According to the analysis of the experimental data, there was a turning point on the curve of ln(Vs) versus ln(l-Φ) under certain pulse intensity. When the holdup is higher than the value at the turning point, the two-phase flow characteristics can be described with the modified Pratt's equation, otherwise a new relation in the form ofΦ=1/2.75uk(uc 4ud) may be used, which is proposed by this study.     

费托合成反应体系的气液平衡研究进展

对费托合成反应体系的气液平衡研究进展进行了归纳和分析,对该体系的物质进行了分类,讨论了不同计算方法的适用性和计算准确性. 可将体系划分为烃类产物和小分子气体两部分,烃类产物又可分为C18以下的轻质烃类和C18以上的重质烃类. 在兼顾计算准确性和简单性的前提下,C18及以下的轻质烃类的气液平衡可采用Raoult定律计算,重质烃类由于存在扩散限制作用,其气液平衡可通过状态方程计算,PR方程计算结果准确性较高. 小分子气体的溶解平衡计算较多应用Henry定律法和状态方程法,Henry定律法计算过程较简单且准确性较高.     

异丁烷/丁烯固体酸烷基化固定床反应器模型研究

针对异丁烷/丁烯固体酸烷基化固定床工艺过程,建立了一维动态传质模型,并对点活性与有效扩散系数的关联式进行了修正。模型计算结果与实验数据吻合良好,验证了模型的准确性。考察了反应器内烯烃和点活性的时空分布情况,并确定了固体酸催化剂失活的主要原因：反应器入口处,活性位覆盖是催化剂失活的主要原因;随着反应器床层高度增加,孔道堵塞逐渐成为催化剂失活的主要原因。     

浊度法测定悬浮液中固体颗粒浓度的研究

采用浊度法分别对9种含有不同颗粒的悬浮液进行检测。结果表明,在实验浓度范围内,悬浮液的浊度（T）同颗粒质量浓度（C）具有良好的线性关系,可表示为 。通过数据分析,发现常数τ与颗粒平均粒径（d32）无关而与颗粒密度（ρs）有关,τ与ρs的关系可表示为 。通过浊度法,采用本文得到的公式可以比较准确地计算悬浮液中的颗粒浓度,相对误差在25%以内。     

聚并-分散脉冲筛板萃取塔的传质与轴向混合特性

A new configuration of coalescence-dispersed pulsed-sieve-plate extraction column (CDPSEC) was developed, and the mass transfer and axial mixing characteristics were evaluated with the two-point dynamic method.The influence of operation conditions was discussed with experimental results, showing that the mass transfer performance of CDPSEC mainly depends on the energy input and the holdup of dispersed phase. Higher energy input results in higher holdhp of the dispersed phase, the axial mixing of the continuous phase is suppressed, and the true height of mass transfer unit decreases markedly. On the other hand, higher energy input leads to more serious forward mixing of the dispersed phase, so the energy input should be limited. Accordingly the operation conditions were divided into two regions, and empirical correlations for predicting the mass transfer and axial mixing characteristics in different regions with a satisfactory accuracy were suggested.