Application of the method of discrete-pulse energy input for water degassing in municipal and industrial boilers

Abstract

The main advantages and disadvantages of chemical and physical degassing of liquids are considered. It was found that hydrodynamic cavitation should be considered as an important alternative to acoustic cavitation, both in terms of performance and, above all, in terms of energy saving. The processing of two liquids - acidic condensate and model solution (solution of carbon dioxide in distilled water) was performed. The dynamics of changes in the content of dissolved carbonic acid depending on the duration of hydrodynamic treatment in order to determine the optimal processing duration to achieve the required degree of degassing are studied. Liquids were treated on a l laboratory-scale plant developed as part of the implementation of the method of discrete-pulse energy input into heterogeneous media, which creates conditions for intensive growth of vapor bubbles and their removal. The pH values were obtained and the concentrations of carbonic acid in the acidic condensate and the model solution were calculated from the duration of their processing. It was found that the main change in the pH of the model solution and acidic condensate occurs approximately during the first two minutes of processing. The increase in pH and, consequently, the decrease in the dissolved carbonic acid content of both liquids for several days are explained by the relaxation process during which carbon dioxide microbubbles emerge from the liquid, which did not have time to leave the liquid. Data from experimental studies of the dynamics of dissolved carbonic acid content, together with theoretical studies of the growth of gaseous bubbles in liquid and the evolution of a set of vapor bubbles to a critical value of gas content can be used to optimize cavitation degassing processes and justify optimal parameters of these processes. The proposed method of degassing can be used for reagent-free neutralization of acid condensate, which will improve the environment by reducing wastewater (chemically contaminated neutralized condensate and waste water softeners) and rational use of water resources by reducing the need for natural water. Also, the proposed method of liquid degassing can be used in the food industry, in particular, in the production of juices, beverages, vegetable oils, etc.