Analysis of Equilibrium PSA Performance with an Analytical Solution

Five-step PSA cycles consisting of pressurization with product, adsorption, co-current depressurization, blowdown, and purge steps have been analyzed with equilibrium model assuming uncoupled linear isotherms and isothermal condition. Unlike the previous models, the proposed model is not restricted to the operating conditions that ensure a complete shock transition of concentration profile at the end of the high pressure adsorption step. The operating conditions could have two classifications: one is utilizing the column completely before blowdown, and the other is not. As the selectivity increases, it is more difficult to utilize the column completely before the blowdown step. There is an optimum co-current depressurization pressure which maximizes the recovery at the given extent of purge. The optimum co-current depressurization pressure decreases as the purge quantity decreases. On the less selective adsorbent, the recovery at the optimum co-current depressurization pressure increases with the decrease of purge quantity without much sacrifice of the throughput. But, on the highly selective adsorbent, there is an extent of purge and corresponding value of cocurrent depressurization pressure below which the recovery is not greatly improved while the throughput decreases rapidly, which limits the number of pressure equalization steps can be included.     

High CO2‐Capture Ability of a Porous Organic Polymer Bifunctionalized with Carboxy and Triazole Groups

A new porous organic polymer, SNU‐C1 , incorporating two different CO₂‐attracting groups, namely, carboxy and triazole groups, has been synthesized. By activating SNU‐C1 with two different methods, vacuum drying and supercritical‐CO₂ treatment, the guest‐free phases, SNU‐C1‐va and SNU‐C1‐sca , respectively, were obtained. Brunauer–Emmett–Teller (BET) surface areas of SNU‐C1‐va and SNU‐C1‐sca are 595 and 830 m²g^?1, respectively, as estimated by the N₂‐adsorption isotherms at 77 K. At 298 K and 1 atm, SNU‐C1‐va and SNU‐C1‐sca show high CO₂ uptakes, 2.31 mmol g^?1 and 3.14 mmol g^?1, respectively, the high level being due to the presence of abundant polar groups (carboxy and triazole) exposed on the pore surfaces. Five separation parameters for flue gas and landfill gas in vacuum‐swing adsorption were calculated from single‐component gas‐sorption isotherms by using the ideal adsorbed solution theory (IAST). The data reveal excellent CO₂‐separation abilities of SNU‐C1‐va and SNU‐C1‐sca , namely high CO₂‐uptake capacity, high selectivity, and high regenerability. The gas‐cycling experiments for the materials and the water‐treated samples, experiments that involved treating the samples with a CO₂‐N₂ gas mixture (15:85, v/v) followed by a pure N₂ purge, further verified the high regenerability and water stability. The results suggest that these materials have great potential applications in CO₂ separation.     

Golf Swing Motion Analysis: An Experiment on the Use of Verbal Analysis in Statistical Reasoning

The complexity of human body demands statistical reasoning to perform an analysis of the golf swing. Such reasoning depends on the use of the Informational Data Set, composed of the related objective knowledge, empirical findings, and observational data. Since the image can be described only verbally and the Informational Data Set requires verbal handling the analysis is performed by constructing a verbal model of the swing motion. The analysis reveals two prototypes of swing motion that can produce an image of actual swing motion. It also produces structural explanations of some of the findings by Ben Hogan. The cusp appearing in the locus of the grip is pointed out as the key to the successful realization of the golf swing. It is tacitly assumed that the golfer is right-handed. The possibility of drastic expansion of the realm of statistics by the use of verbal modeling is pointed out.     

不同材料全等形摆的演示与分析

本文给出系列易加工的不同材料的全等形摆的实验演示规律，对全等形的圆环（圆弧）摆、偏心柱摆等几种特例进行了实验演示测量并与理论进行了对比分析．     

谱分析在我国经济波动理论中的应用

本文讨论经济波动研究的谱分析方法。在对我国主要宏观经济指标的数据序列进行一元、二元谱分析的基础上，对于我国经济波动的机制及运行规律进行定量分析     

关于传统扭摆法测物体转动惯量实验的改进

本文针对传统扭摆法测物体转动惯量系统误差较大的缺点,在扭摆的改进和实验数据的处理方面提出了行之有效的方法,从而达到减小系统误差的目的。     

Radial flow rapid pressure swing adsorption

A new PSA process has been proposed and experimentally verified. This process was operated with a radial flow geometry under a cycle time less than 30 seconds. It has been showed that enriched oxygen could be produced when air was fed inward. The same system showed virtually no separation effect if the feed direction was reversed. The change of separation efficiency upon flow reversal was most significant when small adsorbent particles were employed. A ø 200×75 mm annular packing with 3 µm particles of zeolite 5A was able to produce 60% purity oxygen from air. The effect of flow direction on system performance confirmed the importance of flow resistance distribution. In radial flow geometry, most of the flow resistance was located near the center of the disk. The relative small pressure gradient at the feed end enabled a better absorbent utilization during the inward feed step, and a more effective desorption during the vent step. The same principle could be extended to other geometric configurations.     

Study on Pressure Swing Adsorption Removing C2^＋ from Natural Gas as Raw Material for Thermal Chlorination

The experimental investigation demonstrates that a setisfactory can be expected for pressure swing adsorption (PSA) purification of natural gas as raw material for thermal chlorination process.Using hh-4 molecular sieve as adsorbent for removing C2^ components,the suitable adsorption pressure is 0.4-0.45 MPa,desorption vacuum is 0.08-0.09 MPa and circulation time is 20-21 min.     

Fractional factorial design study of a pressure swing adsorption-solvent vapor recovery process

A two-level fractional factorial study was performed by computer simulation on the periodic state process performance of a pressure swing adsorption-solvent vapor recovery process (PSA-SVR). The goal was to investigate factor (parameter) interaction effects on the process performance, i.e., interaction effects that cannot be ascertained from the conventional one-at-a-time approach. Effects of seven factors, i.e., the purge to feed ratio, pressure level, pressure ratio, heat transfer coefficient, feed concentration, feed volumetric flow rate and bed length to diameter ratio, on the process performance were investigated. The results were judged in terms of the light product purity, heavy product enrichment (and relative enrichment) and recovery, and bed capacity factor. Only the purge to feed ratio, pressure ratio, and feed concentration had significant effects on the benzene vapor enrichment (and relative enrichment); and no two-factor and higher interactions were observed. The light product purity was affected by all seven factors; and the relative importance of the effect of each factor depended on the levels of the other factors, i.e., significant two-factor interaction effects existed. Two-factor interaction effects also existed on the benzene vapor recovery, although the effects of all seven factors and their interactions were relatively small. The bed capacity factor was affected mainly by the purge to feed ratio, the heat transfer coefficient and the feed concentration; two factor and higher order interaction effects were insignificant. Overall, this study demonstrated the utility of fractional factorial design for revealing factor interactions and their effects on the performance of a PSA-SVR process.Nomenclature BCF bed capacity factor, % - b, b ₀ isotherm parameters, m³/(mol K^0.5) - C _pg gas phase heat capacity, kJ/(kg K) - C _ps solid phase heat capacity, kJ/(kg K) - E enrichment - E _I ideal enrichment - E _R relative enrichment - H heat transfer coefficient, kJ/m² s K) - H heat of adsorption, kJ/mol - k number of factors, or mass transfer coefficient, l/s - l number of levels - L bed length, m - LD bed length to diameter ratio - PF purge to feed ratio - P _H adsorption high pressure, kPa - P _L desorption pressure, kPA - PL pressure level, represented byP _I - PR pressure ratio - q amount adsorbed, mol/kg - q ^xx equilibrium amount adsorbed, mol/kg - q ^xx _j equilibrium amount adsorbed at the feed conditions, mol/kg - r _b bed radius, m - R solvent vapor recovery, % or gas constant, m³ (mole K) - T temperature, K - T ₀ ambient temperature, K - t time, s - u interstitial velocity, m/s - VF volumetric feed flow rate, m³ STP/s - YF feed mole fraction - Y _p light product mole fraction - z axial coordinate, m Greek Symbols _g gas phase density, kg/m³ - _s solid phase density, kg/m³ - bed void fraction