Treatment in Continuous Flow Filters Operating in “Hungry” Regeneration Regime for Heating Networks

Abstract

The article discusses a new efficient technology for the preparation of additional water in heating networks. According to the technology, additional water is prepared through the process of cationization using polyfunctional sulfonated coal cationites regenerated with a stoichiometric amount of salt. The research was carried out according to a continuous flow scheme. To obtain accurate results, a laboratory setup was prepared by approximating the height of the cationite and the average diameter of its particles to the required values relative to the diameter of the filter (d : D < 1 : 20) by adjusting the operating regime of the filter closer to industrial conditions. The regeneration regime of the cationite is selected in such a way that the amount of salt in the filtrate during water treatment does not exceed 3–6% of the amount of salt absorbed by the cationite. The main goal of the newly developed technological regime is to reduce the specific consumption of salt during regeneration, increase the exchange capacity of the cationite, and improve both the economic and ecological indicators of the process. As a result of the research, it can be concluded that the exchange capacity of the cationite varies within the interval of 7–20% under the influence of selected factors, and when the specific consumption of salt is increased from 8 to 16 kg/m³, the exchange capacity of the cationite approximately doubles. It should be noted that when the carbonate index in the treated water increases due to the presence of carbonate and hydrogen ions, the degree of water softening increases. However, the rapid rise of the carbonation value in the filtrate increases the average value of the carbonate index and leads to fouling of the filter, which results in a lower exchange capacity of the cationite compared to the mentioned values. It should be emphasized that depending on the values of alkalinity and specific consumption of the regenerant during the process, the filtrate volume of the treated water exiting the filter becomes 2–12% of the total volume and is characterized by saltiness. The salinity in the filtrate is neutralized by the buffer filter.