In the article an algorithm for calculating the continuous ion exchange column is proposed. By analogy with the calculation of the optimal phlegm number of the rectification column this algorithm takes into consideration depreciation charges for capital costs associated with the size of the column and working capital associated with the consumption of ionite and its regeneration. This algorithm can be used to calculate depreciation charges for capital costs related to column sizes and working capital regarded to ionite consumption and regeneration. Examples of ionite consumption calculation at typical and proposed algorithms of calculation and technological and geometric parameters used in column of water purification from sodium cations are given. Thus, in a typical calculation, when the water being purified from sodium cations moves in the ideal displacement mode and the excess of ionite is 1% of its minimum consumption. The optimal ionite consumption corresponding to the minimum of capital costs and working capital, which requires an increase in the ionite consumption by 5.6% of its minimum consumption. In this case the cost of ion exchange increases by 4.5%. It confirms the recommendations for industrial operation and design of ion exchange columns and increases the minimum ionite consumption by 1÷10%. The continuous ion exchange column was calculated including the longitudinal diffusion. Necessity of the further increase of the ionite consumption with regard to the longitudinal diffusion is shown. In the article an example of the ion exchange process calculation in comparison with the typical one, when the displacement mode for the treated water is ideal, is given. Similar equations for the dependences of the concentration of extracted ions in the purified solution and ionite granules are proposed if the equilibrium dependence is described by a linear equation. The working line is dependent on the concentration of the extracted ions in an ionite and on their concentration in the purified water, first, because of a jump in concentration at the inlet and a concave shape of the working line (the latter is usually a straight one in case of the mass-transfer processes) reduces the local and average driving forces of mass-transfer process significantly. It leads to increasing of the moving layer height of the ion exchanger in the column 2 times, and can lead to crossing the line of equilibrium by reducing the concentration jump at the entrance. Consequently, it is necessary to increase ionite consumption by more than 18% compared to its minimum consumption.
The analysis of differential equations of material balance with mass transfer taking into account longitudinal diffusion on both phases in a packed absorber and a distillation column is carried out. It is proposed according to the known algorithms for the calculation of absorption processes to calculate the working lines separately for two cases: 1) solid phase moves in the mode with longitudinal diffusion and dispersion in the ideal displacement mode; 2) continuous phase moves in the ideal displacement mode and dispersion mode with longitudinal diffusion, and then by summing the ordinates of the resulting working lines, to its overall significance to him and the equilibrium line on a standard methodology to calculate the height and diameter of the column.
In the article possibility of water solution LiOH tertiary treatment from chlorine anions after electrolysis is viewed. Analyzing the existing purification methods, it is proposed to use the purification of lithium hydroxide in an ion exchange column. A mathematical model and a computational algorithm for ion exchange column having stationary and moving anionite layers AВ-17-08 in ОН-form are given. Relationships of the main parameters such as working cycle period, usage ratio of ionite exchange volume and specific ratio of solution being purified per 1 kg ionite for standard column have been received. The curves of the chlorine anions density in ionite depending on its layer height in the solution being purified in the middle and at the end of the working cycle period are given. In the article recommendations on prevention of ionite granules abrasion during the operation in ion exchange columns are given.
According to the well-known calculating algorithm for the packed absorption column, the main technological parameters and geometric dimensions of the apparatus for hydrogen sulfide containing gases, formed during the separation of crude oil, are determined. A 2,5-n solution of monoethanolamine is selected as the absorbent. Comparative results of the calculations are showing, that the working pressure in the column should be 4 atm, since with their lower values, the flow rate of the absorbent and the size of the column are increasing. The increase in working pressure is impractical, since it will require a transition from centrifugal and compresses pumps to piston pumps. ∏ The obtained parameters were compared for an absorption column in which the flow structure of the gas and liquid phases corresponds to ideal displacement, with the calculation results when the flow structure in the gas phase corresponds to the ideal displacement mode (as in the standard calculation algorithm) and in the liquid phase to ideal mixing. It is shown that, with the Peclet number of longitudinal diffusion pe<40 the height and volume of the column increases by 10 and more percent and should be taken into account when packed columns, intended for absorption processes, are designed. At pe=30 the height and volume of the nozzle in the column increases by 27%. Another feature of the modelling and calculation of devices is a spike in concentration, meaning, that the lower part of the working line will cross the equilibrium. Calculations in thisparticular case show that at ≈ 11 the working line crosses the equilibrium and theoretically column height and volume →∞.
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