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Design of a Solid-Phase Extraction Plant to Purify Rare Earth Elements by High-Performance Chelation Chromatography (HPCC)
Published in Abhilash, Ata Akcil, Critical and Rare Earth Elements, 2019
Richard F. Hammen, John P. Hammen, Christopher R. Hammen
Chemical equilibrium theory’s application in chromatography is well known. The term, “HPLC” is a more general term, and it refers to “high-performance liquid chromatography”. HPLC is a technology that is the basis of an industry with greater than US$ 3 billion annual sales. The technology is highly developed. Separations of closely related molecules or ions are effected in minutes with tremendous resolution between two or more different species. A primary element of chromatographic theory is the term, “theoretical plates”, of separation. The term, “theoretical plates”, has a history in distillation theory, but it basically is a quantification of the size of a zone in which an equilibration event occurs in a distillation or chromatography column. The factor, theoretical plates per meter, refers, fundamentally, to the number of equilibration events that would occur in a column that is 1 m in length. Modern HPLC columns have plate count values exceeding tens of thousands of plates per meter. High-performance chelation chromatography can be defined as a separation process that utilizes a high-performance chromatographic column having a chelating agent associated with it.
Gas Chromatography
Published in Grinberg Nelu, Rodriguez Sonia, Ewing’s Analytical Instrumentation Handbook, Fourth Edition, 2019
Yuwen Wang, Mochammad Yuwono, Gunawan Indrayanto
According to the van Deemter equation (see Figure 23.3), the theoretical plate numbers (N) of a column rely on the flow of the carrier gas used. As noted earlier, the minimum of the curve (minimum H) corresponds to the maximum efficiency of the separation. Increasing the carrier gas flow rate decreases the elution time of the components and hence, shortens analysis time. On the other hand, it decreases the theoretical plate number and thus, decreases the separation efficiency. Theoretically, for each column, the carrier gas velocity should be practically optimized for the best separation efficiency. However, depending on the type of the column and the carrier gas used, a practical compromise must be reached to determine the best flow rate for minimum H.
Physical Properties Analyzers—ASTM Methods
Published in Béla G. Lipták, Analytical Instrumentation, 2018
N. S. Waner, A. Alston, D. E. Podkulski
Distillation analyzers were introduced to provide data on the volatility characteristics of process streams and separation efficiency of distillation units. ASTM Method D 86-IP-123 is the currently accepted laboratory standard for determining the boiling characteristics of petroleum products distilled at atmospheric pressure. The method employs a batch technique and approaches a single plate distillation process without reflux. The petroleum products analyzed are complex mixtures of components, and a low level of fractionation is achieved. True boiling point distillations, in columns with 15 to 100 theoretical plates and at reflux ratios of 5:1 or more, produce greater separation of components. The apparatus and procedure for true boiling point determinations are not standard, are complex, take longer to perform, and are not as widely used.
Comparison of AWD to CECE for ITER-Scale Water Detritiation
Published in Fusion Science and Technology, 2023
Musharaf Rabbani, Anthony Busigin, Haiqin Mao, Nisa Halsey, Dayna La Barbera
Figure 5 shows the concentration profiles within the WD column. Theoretical plate 1 represents the condenser, and theoretical plate 550 represents the reboiler. The reboiler has the maximum tritium concentration, and the condenser has the minimum tritium concentration. Water with 18O and 17O is also enriched in the bottom of the column. Figure 6 shows the vapor and liquid composition profiles within the column. WD operates under vacuum. The temperature in the reboiler is around 55°C, and the temperature in the condenser is around 37°C. Figure 7 shows the temperature and pressure profile within the WD column. The pressure drop from the reboiler to the condenser is 10 kPa. The pressure drop across WD has close to a linear profile.
Operational optimization of absorption column in capturing CO2 from flue gas in coal-fired power plant
Published in Chemical Engineering Communications, 2021
Palash Panja, Tyrell Xavier Pack, Milind Deo
In this ASPEN model, metal FLEXIPAC packing (vendor Koch-Glitsch) is used. The dimension of the packing is 250Y, where the ‘Y’ indicates the packings with a nominal inclination of 45 °C and the number 250 indicates the surface area of 250 m2/m3. Besides, the efficiency of the 250Y FLEXIPAC structured packing as estimated by HETP (Height Equivalent to a Theoretical Plate) based on atmospheric distillation with low relative volatility and good liquid vapor distribution is 12.4 inch or 315 mm. The rate-based model is used for the calculations. Flue gas enters the bottom and the lean MEA stream enters the top of the absorber. The exhausted flue gas exits from the top after some CO2 is captured and rich MEA stream exits from the bottom. The absorber diameter is kept constant to 9 m for all simulations.
Energy-saving technology of styrene unit based on mechanical vapor recompression coupled with organic Rankine cycle process
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Deming Yang, Tao Li, Bingqin Leng
In the introduction of the Peng-Rob equation, Aspen software specifically pointed out that in order to obtain the most accurate simulation results, the binary parameter kij needs to be corrected from the measured data. Therefore, the key to correcting the thermodynamic model is to modify the binary interaction parameter kij. Fortunately, the kij parameter is obtained in the literature (Luyben 2011). Table 1 present reasonable deviation between the kij of EB/ST obtained in the literature and from Aspen software is 2.2%. Moreover, it is further validated that Peng-Rob model is the optimal model, different models such as NRTL, WILSON, and RK-Sovae are used to simulate the distillation column for separating EB and ST under the same conditions (number of theoretical plate, reflux ratio, etc.). Table 2 reveals the purification of EB and ST in different thermodynamic models and the resolution by Peng-Rob is closest to the actual parameters (Liu 2008).