精馏塔负荷性能图分析技术新发展

系统介绍了按照流体力学极限和传质操作限制来构造精馏塔负荷性能图的方法.提出了适用于进料条件全面变化的可行稳定域分析方法,将塔板负荷性能图分析由一条线拓展到一个面;首次以平衡级离散填料床的方法构造了填料塔的负荷性能图;推荐以降液管入口液速作为负荷性能图的横坐标,不仅统一了塔板负荷性能图的纵、横坐标单位,也为塔板/填料混合型精馏塔实现全塔分析奠定基础.在此基础上提出了全塔负荷性能图的新分析方法,将精馏塔的分析由单层塔板、单段填料上升到全塔的范畴,进行精馏塔瓶颈分析、塔板/填料匹配设计十分容易、便利,是最简单的精馏塔瓶颈分析方法.

输电线路抢修塔中拉线初始倾角的研究

为研究输电线路抢修塔拉线对地倾角变化对抢修塔结构力学性能的影响,以220kV输电线路抢修塔为例,采用ANSYS分析软件构建了抢修塔结构非线性有限元模型,依据规范分析了抢修塔最不利大风工况,并选取7种拉线对地倾角。计算比较结果表明,综合考虑5种力学性能指标,可获得拉线最佳对地倾角,满足抢修需要。

4组分隔板塔热耦合精馏节能技术

对丙醇/丁醇/3-甲基丁醇/2-乙基丁醇组成的4组分物系的分离从完全热耦合原理出发,详细阐述了该物系精馏过程的建立模型到模拟计算,讨论了热耦合过程的自由度和隔板塔的最佳塔段数,指出了操作变量和完全热耦合在最佳热力学状态下应满足的条件,通过化工流程模拟软件Aspen Plus 11.1对该物系的分离工艺从简捷法到严格法计算和最后的优化设计,分析了模拟结果,相比一般的序列塔分离工艺,完全热耦合塔序列即隔板塔节能15.1%,设备材料节省约38%,节能效果明显。并且从用能分析方面讨论了隔板塔内隔板传热利弊和回收热量的多少以及隔板的设计要求。

ADV高效塔盘在芳烃抽提装置改造中的应用

介绍了ADV微分浮阀塔盘的结构特点及其在芳烃抽提装置改造中的工业应用情况。实践证明,在塔径、塔高、塔盘数不变(塔体利旧)的前提下,用ADV微分浮阀塔盘代替传统浮阀塔盘,可以使分馏塔的生产能力提高25%以上,操作弹性完全能够满足产品分离精度要求,适宜在装置扩能改造中使用。

OXO低板间距异构物塔扩能改造

通过对齐鲁二化丁辛醇异构物塔的成功改造,着重介绍了低板间距的塔盘设计要点,同时也介绍了在壳体设备不动火的改造下该塔改造后的塔盘运行效果。

低温甲醇洗循环甲醇中氨含量对系统影响的研究

本研究基于低温甲醇洗(LNG)技术,探讨了循环甲醇中氨含量对系统的影响。首先,通过实验测定了在不同温度和压力下,氨对甲醇的吸附情况。然后,根据测定结果建立了氨在甲醇中的吸附等温线模型,并模拟分析了氨含量对甲醇洗塔性能的影响。结果表明,氨对甲醇的吸附效果随着压力的升高而增大,随温度的升高而减小。在压力7.3MPa和温度253K的情况下,饱和吸附容量达到最大。过高的氨含量会导致甲醇洗塔的处理能力下降和洗塔重量增大。通过对氨的物理处理,可以有效降低甲醇中氨的浓度,从而提高洗塔的运行效率。本研究的结果为控制循环甲醇中氨的含量提供了理论基础和工程参考。

Adsorption Properties of Adsorption Tower Filled with Calcium Superphosphate on NH_3 Emitted from Composting System of Animal Wastes

[Objective] This study aimed to investigate the adsorption properties of the adsorption tower filled with calcium superphosphate on ammonia volatilized with aer- ation. [Method] Adsorption tower filled with calcium superphosphate was adopted as experimental apparatus, which was constructed by poly vinyl chloride （PVC） circular tubes. With hartshorn as the source of ammonia volatilization, the effect of different ratios of height to diameter of the tower filled with equal amount of calcium super-phosphate on ammonia adsorption was investigated. In addition, adsorption tower with height-diameter ratio of 9.9 was selected to adsorb the ammonia emitted from the composting systems of pig manure and chicken manure with optimized and reg- ulated carbon-nitrogen ratio. [Result] Under certain volatilization rate, calcium super- phosphate particles in the adsorption tower could effectively adsorb the ammonia, and the adsorption efficiency was enhanced with the increase of height-diameter ra-tio, which could reach above 90% with height-diameter ratio of more than 1.1; the ammonia emitted from composting systems of pig manure and chicken manure with optimized and regulated carbon-nitrogen ratio could be completely absorbed using adsorption tower with height-diameter ratio of 9.9 filled with calcium superphosphate accounting for about 8% of the weight of composting materials. [Conclusion] Experi- mental results of this study provided reference for the application of adsorption tower filled with calcium superphosphate in the treatment of waste gas emitted from com- posting materials.

Ice melting performance of deicers and their effect on stripping resistance of asphalt mixture

The ice melting performance of three types of deicers, including sodium chloride, calcium chloride and sodium acetate, were tested in laboratory under different temperature conditions, and their effects on asphalt mixture were evaluated from the point of the stripping resistance of asphalt mixture. Unsaturated Marshall samples were exposed to freeze-thaw cycling while immersed in the deicer solutions of different concentrations. After the freeze-thaw cycles, Cantabro tests were performed, and Cantabro loss was adopted to characterize the stripping resistance of asphalt mixture. The test results show that calcium chloride has the best comprehensive ice melting performance, and all deicers have detrimental effect on the stripping resistance of asphalt mixture at different degrees. The damage degree depends on deicer types and their concentration in the solution. Deicer solutions with about 2% concentration cause the greatest loss of stripping resistance due to serious freeze-thaw damage. Sodium acetate causes greater loss of stripping resistance than sodium chloride and calcium chloride at the same concentration.

Prediction of Distillation Column Performance by Computational Mass Transfer Method

A computational mass transfer model is proposed for predicting the concentration profile and Murphree efficiency of sieve tray distillation column. The proposed model is based on using modified c＇2 -εc＇ two equations formulation for closing the differential turbulent mass transfer equation with improvement by considering the vapor injected from the sieve hole to be three dimensional. The predicted concentration distributions by using proposed model were checked by experimental work conducted on a sieve tray simulator of 1.2 meters in diameter for desorbing the dissolved oxygen in the feed water by blowing air. The model predictions were confirmed by the experimental measurement. The validation of the proposed model was further tested by comparing the simulated result with the performance of an industrial scale sieve tray distillation column reported by Kunesh et al. for the stripping of toluene from its water solution. The predicted outlet concentration of each tray and the Murphree tray efficiencies under different operating conditions were in agreement with the published data. The simulated turbulent mass transfer diffusivity on each tray was within the range of the experimental result in the same sieve column reported by Cai et al. In addition, the prediction of the influence of sieve tray structure on the tray efficiency by using the proposed model was demonstrated.

A Novel SiC Foam Valve Tray for Distillation Columns

The novel SiC foam valve tray was made of thin slices of SiC foam material with a high specific surfacearea. Hydrodynamic performances of the novel SiC foam valve tray were studied with air-water system at atmos-pheric pressure. These performance parameters included pressure drop, entrainment, weeping and clear liquidheight. The mass transfer efficiency of the SiC foam valve tray was measured in laboratory plate column. Comparedwith the F1 float valve tray, the dry pressure drop was decreased about 25%, the entrainment rate was about 70%lower at high gas load, the weeping was much better, and the mass transfer efficiency was far higher. Thus, theoverall performance of the novel SiC foam valve tray was better than that of F1 float valve tray.

Performance of CO_2 absorption in a diameter-varying spray tower

The application of spray towers for CO2 capture is a development trend in recent years. However, most of the previous jobs were conducted in a cylindrical tower by using a single spray nozzle, whose configuration and performance is not good enough for industrial application. To solve this problem, the present work proposed a diameter-varying spray tower and a new spray mode of dual-nozzle opposed impinging spray to enhance the heat and mass transfer of CO2 absorption process. Experiments were performed to investigate the mass transfer performance （in terms of the CO2 removal rate （η） and the overall mass transfer coefficient （KGae）） of the improved spray tower under various operating conditions. Experimental results showed that the liquid to gas ratio and mole ratio of MEA to C02 are major factors, which affect the absorption performance and the maximums of η and KGae that are 94.0% and 0.574 kmol. m^-3·h^-1·kPa^-1, respectively, under the experimental conditions. Furthermore, new correlations to predict the mass transfer coefficient of the proposed spray tower are developed in various CO2 concentrations with a Pearson Correlation Coefficient over 90%.

The Design and Control of Distillation Column with Side Reactors for Chlorobenzene Production

The distillation column with side reactors (SRC) can overcome the temperature/pressure mismatch in the traditional reactive distillation, the column operates at temperature/pressure favorable for vapor-liquid separation, while the reactors operate at temperatures/pressures favorable for reaction kinetics. According to the smooth operation and automatic control problem of the distillation column with side reactors (SRC), the design, simulation calculation and dynamic control of the SCR process for chlorobenzene production are discussed in the paper. Firstly, the mechanism models, the integrated structure optimal design and process simulation systems are established, respectively. And then multivariable control schemes are designed, the controllability of SRC process based on the optimal steady-state integrated structure is explored. The dynamic response performances of closed-loop system against several disturbances are discussed to verify the effectiveness of control schemes for the SRC process. The simulating results show that the control structure using conventional control strategies can effectively overcome feeding disturbances in a specific range.

Hydrodynamics and Mass Transfer Performance in Supercritical Fluid Extraction Columns

New models for describing hydrodynamics and mass transfer performance in supercritical fluid extraction columns were proposed. Those models were proved by experimental data, which were obtained in supercritical fluid extraction packed column, spray column and sieve tray column respectively. The inner diameter of those columns areФ25 mm. These experimental systems include supercritical carbon diox-ide-isopropanol-water and supercritical carbon dioxide-ethanol-water, in which supercritical carbon dioxide was dispersed phase, and another was continuous phase. The extraction processes were operated with continuous countercurrent flow. The predicted values are agreed well with experimental data.

Novel High Performance Ziegler-Natta Catalyst for Ethylene Slurry Polymerization

A novel high performance MgCl2/TiCl4 catalyst with tetrabutyloxsilicane as electron donor was pre-pared for ethylene slurry polymerization process. The properties of the catalyst such as particle size distribution, catalytic activity, hydrogen responsibility and copolymerization performance were investigated and compared with commercial catalyst (imported catalyst). Copolymerization of ethylene and 1-butylene using the catalyst was stud-ied in a pilot plant. The composition, structure and property of the copolymer were characterized by 13C nuclear magnetic resonance (13C NMR) and gel permeation chromatography-Infrared (GPC-IR), and compared with those of the copolymer obtained from a commercial catalyst. In comparison with the commercial catalyst, the novel cata-lyst had a higher activity (up to 34.6 kg·g-1) and a better particle size distribution (PSD), and produced polymers having higher bulk density (up to 0.37 g·cm-3) with less fine resin. Meanwhile, the novel catalyst showed a higher hydrogen responsibility and better copolymerization performance. The results indicated that the copolymer obtained from the novel catalyst has a higher branch in the high molecular weight fraction and lower branch in the low mo-lecular weight fraction.

Model experiment on anti-deformation performance of a self-supporting transmission tower in a subsidence area

A large number of high-voltage power transmission towers have recently been constructed in mining areas prone to subsidence. In order to ensure the safety of the transmission towers and the safe operation of transmission systems, it is imperative to carry out research on the anti-deformation performance of transmission towers. In our study, we performed experiments on the anti-deformation performance of a transmission tower in a subsidence area on a scale model with a geometric scale ratio of 1:5 and analyzed the failure mechanism of the tower members. The results show that, when the axial distance between two supports changes, destabilization failure most likely occurs in the members of the bottom transverse layer because some parts of the main diagonal member bars yield under the action of compression. The failure mechanism of the tower members basically coincides with the lever principle.

Study on Improvement of Seismic Performance of Transmission Tower Using Viscous Damper

The earthquake resistance of transmission tower has been often discussed from the viewpoint of reinforcing the foundation of steel tower, but there are also few studies considering the damping characteristics of the tower. This paper focuses on the viscous damper which has been adopted for seismic reinforcement of bridges in recent years. The purpose of this study is to improve the seismic performance of steel tower by giving the high damping to the tower. We construct a single tower model considering the influence of transmission line, and then simulate the vibration characteristics and seismic behavior of the tower by the eigenvalue analysis and the dynamic response analysis. The results show that the transmission tower with viscous damper can reduce its own response effectively and drastically. This research concludes that it is necessary to consider the extreme increase of steel tower＇s response depending on the seismic wave and the collapse of steel tower can be avoided by using the optimum damper in the design of the transmission tower.

Numerical Investigation on Effect of Vapor Split Ratio to Performance and Operability for Dividing Wall Column

Operability problem of dividing wall column (DWC) raised by vapor split was investigated by numerically analyzing four cases defined by different compositions of a three-component mixture. DWCs were firstly designed for each case by optimizing the vapor split to the two sides of the dividing wall, and then their feasibilities and total annual costs in operation were evaluated against different vapor split ratios. The analysis on the operability of the DWC for four cases was made based on two scenarios: (1) vapor split is shifted by the vapor resistance difference between the column sections in the two sides of the dividing wall and (2) the feed composition is changed. It was demonstrated that the positioning of the dividing wall and the decision on the vapor split may affect significantly the operability of a DWC.

Numerical Simulation of Wind Turbine Blade-Tower Interaction

Numerical simulations of wind turbine blade-tower interaction by using the open source OpenFOAM tools coupled with arbitrary mesh interface （AMI） method were presented. The governing equations were the unsteady Reynolds-averaged Navier-Stokes （RANS） which were solved by the pimpleDyMFoam solver, and the AMI method was employed to handle mesh movements. The National Renewable Energy Laboratory （NREL） phase VI wind turbine in upwind configuration was selected for numerical tests with different incoming wind speeds （5, 10, 15, and 25 m/s） at a fixed blade pitch and constant rotational speed. Detailed numerical results of vortex structure, time histories of thrust, and pressure distribution on the blade and tower were presented. The findings show that the wind turbine tower has little effect on the whole aerodynamic performance of an upwind wind turbine, while the rotating rotor will induce an obvious cyclic drop in the front pressure of the tower. Also, strong interaction of blade tip vortices with separation from the tower was observed.

Mass transfer performance of structured packings in a CO_2 absorption tower

This paper studies the mass transfer performance of structured packings in the absorption of CO2 from air with aqueous Na OH solution. The Eight structured packings tested are sheet metal ones with corrugations of different geometry parameters. Effective mass transfer area and overall gas phase mass transfer coefficient have been measured in an absorption column of 200 mm diameter under the conditions of gas F-factor in 0.38–1.52 Pa0.5and aqueous Na OH solution concentration of 0.10–0.15 kmol·m-3. The effects of gas/liquid phase flow rates and packing geometry parameters are also investigated. The results show that the effective mass transfer area changes not only with packing geometry parameters and liquid load, but also with gas F-factor. A new effective mass transfer area correlation on the gas F-factor and the liquid load was proposed, which is found to fit experiment data very well.