S型垂直筛板流化床的性能

在S型垂直筛板流化床中,以FCC催化剂和空气作为流化介质,对垂直筛板流化床的流化性能进行冷模实验研究,考察了板孔气速、固体循环量和帽罩结构对床层压降和帽罩提升量的影响,用提升量收集器测量帽罩提升量。实验结果表明,床层压降随板孔气速和帽罩底隙高度的增加而增加,而随塔板开孔直径、帽罩开孔直径和开孔率的增加而下降。帽罩提升量则随板孔气速、固体循环量、塔板开孔直径及帽罩底隙高度的增加而增加;随帽罩开孔直径的增加,提升量先增加后下降。     

ADV(r)微分浮阀塔盘在气体分馏装置中的应用

介绍一种新型高效塔盘-ADV(r)微分浮阀塔盘在气体分馏装置中的应用情况,该塔盘与F1型浮阀塔盘相比生产能力提高40％,分离效率提高10％,操作弹性提高40％。ADV(r)微分浮阀塔盘已在5套改造和3套新建的气体分馏装置的应用中。特别是在塔径、塔高、塔盘数不变即塔体利旧的情况下,用ADV(r)微分浮阀塔盘替换原F1型浮阀塔盘,使各个精馏塔的生产能力提高了40％以上,精丙烯满足了聚合级丙烯纯度的要求,验证了ADV(r)微分浮阀塔盘是一种大通量,高效率的塔盘。     

十字旋阀塔板漏液性能

在φ1000mm的圆塔内,以空气-水为介质,对十字旋阀塔板的泄漏率进行了测试,考察了液流强度、出口堰高等因素对泄漏性能的影响,并将其与交错十字旋阀塔板、组合导向浮阀塔板和F1型浮阀塔板的泄漏率进行了对比。结果表明:十字旋阀塔板在气速超过临界阀孔气速且液流强度较小时具有很好的漏液性能,经数据关联,获得了十字旋阀塔板漏液点孔速的关联式。     

甲醇常压精馏塔底层塔板脱落原因分析及处理措施

造成塔板脱落的直接原因为气流或液流对塔板的冲击力过大所至,这个冲击力与塔的负荷大小、塔釜上升气流的波动情况等有关,这就要求精馏塔板在设计上必须满足额定负荷情况下抗气流的冲击力,同时精馏系统不可能保持在绝对稳定的状态下运行,这就要求精馏塔板必须满足一定范围内的负荷波动要求,因此塔板就应该具有一定的强度;而设计负荷条件下的塔板强度大小就和塔板的安装固定设计、塔径的大小、塔内气流的均匀分布设计等有关。     

Influence of metallic trays on the ac resistance and ampacity of low-voltage cables under non-sinusoidal currents

This paper investigates the influence of metallic trays on the ac resistance of PVC insulated, low-voltage (0.6/1.0 kV) cables made according to CENELEC standard HD603. The investigation is made with a validated finite element model for the fundamental and higher harmonic frequencies. It is shown that the cable's effective resistance is affected significantly by the relative magnetic permeability and specific conductivity of the tray, while the tray's dimensions do not affect it. The orientation of the cable with respect to the tray also influences the ac resistance of the phase and neutral conductors. An ampacity derating factor is defined and calculated for various cable cross-sections and harmonic loads. The presence of a metallic tray is shown to cause an additional derating of cable's ampacity which is relatively significant at large cable cross-sections. Working examples demonstrate the application of the results in calculating the ampacity of low-voltage cables and in assessing the energy savings that will result from the use of active harmonic filters.     

Efficiency of dualflow trays in distillation

The mass transfer efficiencies of dualflow trays with open hole areas of 20, 28 and 37% were experimentally investigated under total reflux conditions in a 300-mm diameter distillation column using methanol-water and methanol-isopropanol systems. The results indicate that the efficiency of a dualflow tray is a strong function of the open hole area, the vapor/liquid load, and liquid properties such as surface tension and density. A fundamental model was developed to predict tray efficiency. The prediction was found to agree with the measured data to within 15.3%.     

CFD优化精馏塔板的液流状况

应用计算机对过程的模拟(仿真)研究是过程系统工程(process systems engineering,简称PSE)的重要组成部分,本文应用计算流体力学(computational fluid dynamics,简称CFD)模拟研究了液流强度和堰径比对精馏塔板液流状况的影响,并且模拟计算了改进塔板液流状况的两种方案:设置不等高入口堰和设置圆弧型的导流板,从模拟结果可以看出,以上两种方案都能够很好的达到优化塔板液流状况的目的。     

The addition of sugarcane bagasse and asparagus peel enhances the properties of sweet potato starch foams

The agro‐industrial wastes, sugarcane bagasse (SB) and asparagus peel (AP), were used to enhance the properties of biodegradable foam trays based on sweet potato starch‐based foam trays (starch/SB and starch/AP trays, respectively). Starch/SB and starch/AP trays containing different concentrations of SB and AP (0%‐40%, w/w) were prepared, and their microstructure and physical, thermal, and mechanical properties were characterized. The addition of fibers wastes allowed obtaining a yellowish foam tray with lower luminosity and higher porosity, mechanical resistance, deformability, and better ability to absorb water as compared with the sweet potato starch foam trays without fibers. The addition of SB yielded foam trays less porous, with lower water absorption capacity and greater tensile strength than the addition of AP. Higher concentrations of AP fibers (greater than 30%) generate more extendible foam trays. The addition of fibrous wastes improved the thermal stability of the sweet potato starch foam trays. The composite foam trays produced in this work could be used as substitutes for expanded polystyrene in dry food packaging.     

Hydrodynamic Characteristics in the Counter‐Flow Total Spray Tray

The capacity of a column is limited by the distribution of gas and liquid, especially in case of large‐diameter cross‐flow trays. In order to solve the bottleneck, a new counter‐flow tray named total spray tray (TST) was put forward. Taking air/water as medium, the hydrodynamic behavior, including the pressure drop, weeping, entrainment, and clear liquid height, was investigated, in comparison with the CTST, which had a higher capacity. Based on experimental data, the correlations of the TST pressure drop were established by regression analysis method. The experimental results show that the TST has a lower wet pressure drop and less weeping. More interestingly, its clear liquid height can be self‐adjusting with the variation of the gas kinetic energy factor, which is beneficial to improving the capacity.