THE OPTIMUM PLATE-SPACING FOR THE BEST PERFORMANCE IN FLAT-PLATE THERMAL DIFFUSION COLUMNS OF THE FRAZIER SCHEME

The effect of plate spacing on the degree of separation and production rate in flat-plate thermal diffusion columns of the Frazier scheme with fixed operating expense, has been investigated. The equations for estimating optimum plate-spacing for maximum separation and for maximum production rate have been developed. Considerable improvement in performance is obtainable when the thermal diffusion columns with optimum plate-spacing are employed for operation.     

Recovery of deuterium from water-isotopes mixture in flat-plate thermal-diffusion columns of the Frazier scheme with optimum plate-spacing

The effect of plate-spacing on the degree of recovery and production rate for the recovery of deuterium from water-isotopes mixture in flat-plate thermal-diffusion columns of the Frazier scheme with fixed operation expense has been investigated. The equations for estimating optimum plate-spacing for maximum recovery and maximum production rate have been developed. Considerable improvement in performance is obtainable when thermal-diffusion columns with optimum plate-spacing are employed for operation.     

THE OPTIMUM PLATE-SPACING FOR THE BEST PERFORMANCE IN A FLAT-PLATE THERMAL DIFFUSION COLUMN WITH TRANSVERSE SAMPLING STREAMS

The equations for estimating optimum plate-spacing for maximum separation and for maximum production rate in a flat-plate thermal diffusion column with transverse sampling stream and with fixed operating expense, have been derived. Considerable improvement in performance is obtainable if the optimum plate-spacing is selected so that the convective strength can be properly reduced and controlled, resulting in suppressing the undesirable remixing effect while still preserving the desirable cascading effect and thereby leading to improved performance.     

The Optimum Plate Aspect Ratio for the Best Performance in a Flat-Plate Thermal Diffusion Column with Transverse Sampling Streams

ABSTRACT

The effects of plate aspect ratio on the degree of separation, production rate, and plate surface area in a flat-plate thermal diffusion column with transverse sampling streams have been investigated. Theoretical considerations show that when a thermal diffusion column is constructed with the best plate aspect ratio, either maximum separation or maximum production rate or minimum plate surface area can be obtained. The optimum plate aspect ratio for maximum separation is obtained with a given production rate and plate surface area, while that for the maximum production rate is determined with the degree of separation and plate surface area fixed, and that for the minimum plate surface area is estimated with a known degree of separation and the production rate. It is interesting that the optimum plate aspect ratio for maximum separation is exactly the same as that for minimum plate surface area. The maximum separation and maximum production rate are achieved without changing the total expenditure, while the design with minimum plate surface area results in minimizing the total expenditure.     

The optimum plate aspect ratio for the best performance in a flat-plate thermal diffusion column of the frazier scheme

The effects of plate aspect ratio on the degree of separation, production rate and plate surface area in a flat-plate thermal diffusion column of the Frazier scheme, have been investigated. Theoretical considerations show that when the thermal diffusion columns of the Frazier scheme are constructed with the best plate aspect ratio, maximum separation, maximum production rate or minimum plate surface area can be obtained. The optimum plate aspect ratio for maximum separation is obtained with given production rate and plate surface area, while that for maximum production rate is determined with the degree of separation and plate surface area fixed, and that for minimum plate surface area is estimated with known degree of separation and production rate. It is interesting that the optimum plate aspect ratio for maximum separation is exactly the same as that for minimum plate surface area. The maximum separation and maximum production rate are achieved without changing any total expenditure, while the design with minimum plate surface area results in minimizing the total expense.     

Enrichment of heavy water in flat‐plate thermal diffusion columns of the frazier scheme with the optimal plate aspect ratio for best performance

The solutions of the optimum plate aspect ratio as well as the corresponding maximum separation, maximum production rate and minimum plate surface area in thermal diffusion columns of the Frazier scheme for enrichment of heavy water have been obtained, analogous to those obtained in the previous work for separation of a binary system. It was found that all the optimum plate aspect ratios do not depend on feed concentration, while the corresponding best performances do. It is found that considerable improvement in performance is obtained when the operation is carried out with the optimal plate aspect ratio.     

The best performance of spiral wired thermal diffusion columns of the frazier scheme

Equations have been derived for the optimum wire angles of inclination for maximum separation, maximum production rate and minimum column height in the Frazier scheme of concentric‐tube thermal diffusion columns with a tight fitting wire spiral, having a diameter equal to the annular spacing, and wrapped on the entire inner tube. Considerable improvement in performance is obtained when a Frazier scheme is operated at the optimum corresponding wire angle of inclination, especially for the scheme of high column number.     

Recovery of Deuterium from Water‐Isotopes Mixture in Flat‐Plate Thermal‐Diffusion Columns of the FRAZIER Scheme with Optimal Plate Aspect Ratio for Improved Performance

Abstract

The equations for estimating the optimal plate aspect ratio as well as the corresponding maximum recovery, maximum production rate, and minimum plate surface area for recovery of deuterium from water‐isotopes mixture in flat‐plate thermal diffusion columns of the Frazier scheme, have been derived. Considerable improvement in performance is obtainable if the operation is carried out with the optimal plate aspect ratio. It was found that all the optimal plate aspect ratios, as well as the improvements in performance, do not depend on feed concentration.     

The Optimum Column Number for the Best Performance of Thermal Diffusion in the Frazier Scheme with the Total Sum of Column Height Fixed

The effect of column number N, as well as the column height h of thermal diffusion columns, on the degree of separation in the Frazier scheme with the total sum of the column height L (=Nh) fixed, has been investigated. The equations, which may be employed to predict the optimum column number N* for the maximum separation Δ _N,max, have been derived. Considerable performance in separation is obtainable if the column number, as well as the column height, in a Frazier scheme with the total sum of the column height fixed is properly assigned for a certain flow-rate operation.     

Thermal diffusion in inclined flat-plate columns of the frazier scheme

The separation theory of thermal diffusion in inclined flat-plate columns of the Frazier scheme has been developed and investigated. The equations for the best angle of inclination and maximum separation have been derived. Considerable improvement in separation is obtained when thermal diffusion columns are operated at the best angle of inclination.     

The Effect of Plate Spacing on the Degree of Separation in Inclined Thermal Diffusion Columns with Fixed Operating Expense

Abstract

It has been found that the maximum separation obtainable in inclined thermal diffusion columns is proportional to the square root of plate spacing when the operating expense is fixed. The plate spacing is generally so small that changing it, as well as changing the angle of inclination, may not cause additional fixed charge. However, increasing the plate spacing will lead to increasing the difference of plate temperatures in order to keep the operating expense unchanged. Therefore, additional cost is needed to maintain a high value of temperature difference.     

Separation Efficiency of Rotary Thermal Diffusion Columns with the Inner Tube Cooled and the Outer Tube Heated

Abstract

Adjusting the temperature gradient to the opposite direction in rotary thermal diffusion columns results in improving the separation efficiency. In the case of small σ, even this modified rotary column gives better separation than the original rotary one developed in previous work.     

Thermal Diffusion Factor for Carbon Tetrachloride-Cyclohexane and Benzene-n-Heptane Mixtures from Thermogravitational Column Separation

Abstract

Measurements of the separation of liquid mixtures of n-heptane/benzene and carbon tetrachloride/cyclohexane in a thermogravitational column are reported. The results show that thermal diffusion columns of little mechanical precision can furnish suitable thermal diffusion factors when the diffusion coefficient, viscosity, density, and compressibility factor for the mixture are known.     

Comparison of Various Methods of Calculating a Separation Factor in Thermal Diffusion

Abstract

An improved equation of separation applicable to the whole range of concentration in flat-plate thermal diffusion columns has been derived by the least squares method. Separations calculated from this equation are more accurate than those from the generalized equation obtained by Yeh and Chu, particularly for low flow-rate operations and equifraction solution.     

The Enrichment of Heavy Water in a Continuous-Type Inclined Thermal Diffusion Column

Abstract

Equations of the best angle of inclination and the maximum separation for the enrichment of heavy water in a continuous-type inclined thermal diffusion column have been derived. Considerable improvement in separation was obtained by employing the inclined column instead of using the Clusius-Dickel column.     

A Study on the Separation Efficiencies of Rotating-Tube Wired Thermal-Diffusion Columns under Higher Flow-Rate Operations

Abstract

Even under higher flow-rate operations, σ > 0.42A ², rotating the tubes oppositely in a wired concentric-tube thermal diffusion column still substantially increases the separation efficiency by improving the cascading effect. The equations for estimating the best tube speed of rotation and maximum separation, with the inclination of the wire angles as parameters, have been derived. The maximum separation increases as the inclination of the wire angle decreases; however, this also leads to increasing the best tube speed of rotation and thereby raising the operating cost.     

THERMAL DIFFUSION IN A FLAT-PLATE COLUMN WITH TRANSVERSE SAMPLING STREAMS

The optimum angles of inclination for maximum separation, maximum production rate and minimum column length in a fiat-plate thermal diffusion column with transverse sampling streams, have been determined. Considerable improvement in performance is obtainable if the column is tilted at the optimum angle, instead of being placed vertically, so that the convection strength can be properly reduced and controlled, resulting in suppressing the undesirable remixing effect while still preserving the desirable cascading effect.     

Effect of plate aspect ratio on the recovery of deuterium from water-isotope mixture in flat-plate thermal diffusion columns with transverse sampling streams

The optimal plate aspect ratios for the best recovery of deuterium from water-isotope mixture in flat-plate thermal diffusion columns with transverse sampling streams have been determined. The maximum recovery and maximum production rate are achieved without changing the total expenditure, while the design with minimum plate surface area results in minimizing the total expense.     

THE COMBINED EFFECT OF INCLINED ANGLE AND PLATE SPACING ON THE PERFORMANCES OF FLAT-PLATE THERMAL-DIFFUSION COLUMNS

When the separation is performed in a parallel-plate thermal diffusion column with the operating expense fixed, either increasing the plate spacing and operating at the corresponding optimum inclined angle, or increasing inclined angle and operating at the corresponding plate spacing, will increase the maximum separation and maximum production rate. Il was found that the cosine of optimum inclined angles increase with the plate spacing in the exponents of -9/2 and —4, respectively, for maximum separation and maximum production rate, while the optimum plate spacings increase with the cosine of inclined angle in the exponents of -2/9 and — 1/4, respectively. The plate spacing is generally so small that changing it, as well as changing the inclined angle, may not cause additional fixed change. However, increasing the plate spacing will lead to increasing the difference of plate temperatures in order to keep the operating expense, as well as the energy consumption due to heat conduction between the hot and cold plates, unchanged. Therefore, additional cost is needed to maintain a high value of temperature difference. There do not exist simultaneously the optimum inclined angle and the optimum plate spacing for the best performances.     

A Study of the Separation Efficiency in the Concentric-Tube Countercurrent Separation Process under Generalized Linear Applied Fields and with Recycles at Both Ends

Abstract

The mathematical model for the separation of binary mixtures has been extended to a concentric-tube continuous-contact countercurrent column under generalized linear external fields and with recycles at both ends. An analytical solution is obtained by use of the orthogonal expansion method. Numerical results for separation in a thermal diffusion column are also illustrated.