Cyclic Separation Techniques
01 Jan 1981-pp 443-515
About: The article was published on 1981-01-01. It has received 14 citations till now.
Citations
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TL;DR: In this paper, Micelles in Separations: Practical and Theoretical Review, Vol. 14, No. 2, pp. 213-304, are discussed and discussed.
Abstract: (1985). Micelles in Separations: Practical and Theoretical Review. Separation and Purification Methods: Vol. 14, No. 2, pp. 213-304.
139 citations
TL;DR: In this article, Gas Purification by Pressure Swing Adsorption Separation and Purification Methods: Vol 14, No 2, pp 157-212, pp 157 and212.
Abstract: (1985) Gas Purification by Pressure Swing Adsorption Separation and Purification Methods: Vol 14, No 2, pp 157-212
49 citations
01 Jan 1986
TL;DR: The concept of parametric pumping is due to Wilhelm and coworkers (1966, 1968) as mentioned in this paper, whose original results deal with adsorption from the liquid phase, modulated by temperature.
Abstract: The term “parametric pumping” implies the idea of pumping, that is of transport of material (in our case, ionic species) up along some potential scale (in our case, chemical potential), at the cost of degradation of some flux of energy (to be specified later). The term “parametric” refers to the fact that the energy flux just mentionned is obtained by modulating some intensive thermodynamic parameter such as temperature, pressure, ionic strength, pH, electric potential, … Typical examples are temperature-swing ion-exchange and pressure-swing adsorption. The concept of parametric pumping is due to Wilhelm and coworkers (1966, 1968). Their original results deal with adsorption from the liquid phase, modulated by temperature. Let us examine how these phenomena are implemented.
14 citations
TL;DR: In this article, a dual-temperature ion exchange fractionation (DTIXF) technique is proposed to design a reagentless and wasteless fractionation technology for IX resins with temperature dependent selectivity.
Abstract: This paper reviews the results obtained by studying the dual-temperature ion-exchange fractionation (DTIXF) technique. The DTIXF is based on the use of different affinity at different temperatures of ion exchangers towards ions to be separated. This technique allows to design absolutely reagentless and, as a result, wasteless fractionation technology. The review considers the temperature dependencies of selectivity of commercially available ion-exchange (LX) resins towards components of ionic mixtures of different complexity starting from binary model systems up to naturally existing nonacomponent effluents. A novel approach for predicting the temperature sensitivity of a given LX system is presented and discussed. The same approach has been shown to be applicable for the design of IX resins with temperature-dependent selectivity. The paper also reports the results obtained in the practical application of DTIXF technique for concentration of magnesium from seawater and copper from acidic mine wat...
12 citations
Dissertation•
21 Nov 1988
TL;DR: In this paper, the authors examined experimentally and theoretically a two-bed process for separating oxygen from air using a zeolite adsorbent, and the model's qualitative agreement with experiments was verified over a wider range of cycles and the quantitative agreement was improved for some cycles.
Abstract: Pressure swing adsorption is a method for separating gases by selective adsorption. It is being used increasingly in industry where for some applications, including air separation, the number of plants have increased at a near exponential rate in recent years. However, despite the many hundred different plant configurations and cycles, there is still a lack of understanding of the basic process steps and plenty of scope for achieving even better plant performances. This study examines experimentally and theoretically a two bed process for separating oxygen from air using a zeolite adsorbent. A plant was designed and built to incorporate the novel feature of recycling waste gas from the purge and depressurization steps back into the feed line and also to investigate conventional purge, backfill and combined cycles. Theoretical modelling had predicted that large amounts of waste gas could be recycled without loss in product oxygen concentration, but causing an improvement in oxygen yield. This was verified experimentally, demontrating potential energy savings. For each cycle investigated the product oxygen concentration and yield were optimized over a range of product amounts per cycle while continually monitoring the main process variables. Other experimental work included studies of the bed temperature and pressure profiles, the waste gas oxygen concentrations, unsymmetrical operation and supplying purge from different sources. The theoretical aims were to further develop the instantaneous local equilibrium (ILE) model used by Kirkby (1984). The model was made more efficient and developed to include novel options for waste recycling and the previously neglected, but common, design feature of supplying purge directly from one bed to another. The model's qualitative agreement with experiments was verified over a wider range of cycles and the quantitative agreement was improved for some cycles.
10 citations
References
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TL;DR: In this paper, the authors present a review of the performance of chemical reactors in the 1970s, focusing on the periODic operation of CHEMICAL REACTORS.
Abstract: (1974). PERIODIC OPERATION OF CHEMICAL REACTORS: A REVIEW. Chemical Engineering Communications: Vol. 1, No. 3, pp. 111-124.
234 citations
TL;DR: In this paper, the authors developed a model to describe sintering of metal crystallites during heat treatment, where the growth rate of such crystallites is assumed to depend upon particle migration over the surface of the support as well as on the rate the colliding particles merge (sinter) into a single unit.
Abstract: Models are developed to describe sintering of metal crystallites during heat treatment. The growth rate of such crystallites is assumed to depend upon particle migration over the surface of the support as well as on the rate the colliding particles merge (sinter) into a single unit. The theory predicts that the rate of decay of exposed metal surface area S is given as in Equation (1a). The exponent n is related to the assumed size dependence of the diffusion coefficients or of the rate constant of the merging process. It varies from 4 to 8 for diffusion controlled decay and it is less than 3 for sintering controlled decay, that is, when the rate controlling step is the merging of two colliding particles. Diffusion control is associated with strong interactions between the metal and the support, but in sintering control there is a weaker metal-support interaction.
149 citations
Esso1
TL;DR: In this paper, a linear mathematical model of heatless adsorption of a trace component obtained by the method of characteristics was used to investigate the effect of CO 2 in excess He.
103 citations
TL;DR: In this paper, a mathematical model based upon the assumption of instantaneous equilibrium between the gas phase and the adsorbed gas was formulated and solved to simulate the periodic, adsorption process.
Abstract: The periodic process utilizes a rapid pressure swing cycle in an adsorbent bed to effect the separation of gas mixtures. During the first portion of a cycle the compressed gas mixture flows into the adsorbent-filled column. Next, while the feed gas is restrained, an exhaust orifice is opened at the feed end of the column providing depressurization. The product stream is enriched in the component exhibiting the lowest coefficient of adsorption.
A mathematical model based upon the assumption of instantaneous equilibrium between the gas phase and the adsorbed gas was formulated and solved to simulate the periodic, adsorption process. The measured nitrogen content of the product gas stream was found to correlate with the ratio of the product gas rate to the feed gas rate.
At 24°C. the calculated pressure response, feed gas flow rate, and product gas composition correspond favorably with related experimental measurements for all values of the feed gas pressure, cycling frequency, and product gas flow rate within the ranges investigated.
93 citations