Математичне моделювання процесів магнітного фільтрування і регенерації та оцінка їх ефективності

Abstract

Удосконалено математичну модель, що описує закономірності процесу магнітного осадження. Запропоновано методику розрахунку ефективності процесів фільтрування та регенерації. Досліджено результати, отримані при фільтруванні та регенерації у фільтрах, які функціонують за законами, прийнятими в узагальненій моделі Мінца.

The results of the investigations deal with the problem of water system purification from the contaminating admixtures. The problem is urgent in heat and nuclear engineering, chemical and metallurgical industries. Conventional methods of water systems purification from the products of corrosion, which are based on the application of filters, the filtering nozzle of which are organic and inorganic materials, are known not to provide high level of purification. The process of filtration is especially complicated while filtering high temperature water media (≈100-200ºC) and when high-depression iron admixtures are available. Numerous investigations have testified that iron admixtures (up to 70-95%) in waters of thermal station equipment possess ferromagnetic properties. The efficiency of purification is testified to be dependent on the quality of the filtering nozzles regeneration, that is, these processes are interconnected. It has been proved that for the purification of technological water systems, in which ferromagnetic admixtures are available, the method of magnetic sedimentation of admixtures in ferromagnetic filtering nozzles, which can be realized in the magnetic filters, is worthy being applied. Magnetic filters operating includes the process of admixtures sedimentation in the filtering nozzles and the nozzle regeneration. It has been testified that nozzles regeneration time affects the filtration cycle duration, that is, the period of time, during which the filter nozzle is maximally saturated by the admixtures. Basing on the experimental results data on the effect of active parameters of the magnetic purification of liquid media upon the mass exchange coefficient, mathematic model, which describes the regularities of the process of admixtures magnetic sedimentation in the magnetized ferromagnetic nozzle, has been improved. The basis of the mathematic model are regularities of the filtering process, which are similar to the theoretical approaches of he Mints mechanical filtration theory. The proposed mathematical model includes a wide range of change of the magnetized filtering nozzle length and sedimented admixtures concentration in filtering nozzle. The model takes into account such parameters: magnetic field stress, granulated filtering nozzle diameter, time of the protective action of the magnetic filter, rate of he liquid media filtering, coefficient, which is the characteristic of he mass amount of the magnetic sediment of the ferromagnetic admixture particles per time unit. Basing on the computer experiment and using the proposed mathematic model the regeneration time, during which the maximal specific density of the nozzle saturation by the admixtures was found to be reduced to 0,5; 0,4; 0,2; 0. Nomograms for determination of the operating filtration cycle of chip and ball-shaped filtering nozzle, the period of nozzle regeneration depending on the input iron concentration and purification efficiency, have been calculated and built. The rate of the water flow regeneration was found to affect sufficiently the regeneration efficiency. Thus, at the rate V=1000 m/h during 2 min the regeneration efficiency is 85% of the maximum possible efficiency. When V=500m/h under the same conditions, the regeneration efficiency is.