Iskanje po katalogu digitalne knjižnice

Opis: The presented research work is focused on the development of an innovative way of economically improving the quality of underground water by the application of carbon dioxide. The basic pilot plant was developed with the idea of applying carbon dioxide in order to maintain the carbonate equilibria in water, pumped from under the ground. The optimal content of this natural component in underground water, used in urban areas for different purposes (e.g. drinking water, heating systems etc), simultaneously prevents corrosion and precipitated mineral deposits. The adaptation of an existing pilot plant started with operational testing and preliminary measurements. An appropriate sensor system for the online monitoring of the tap waterćs heating process measuring parameters such as the temperature, the concentration of dissolved carbon dioxide, the conductivity and the pH value was built in. Different amounts of carbon dioxide were applied during the two experimental stages. The composition of the water was regularly analysed using automatic titration and ionic chromatography. The gas-dosing control in the first phase was volumetric. Due to an observed inaccuracy in the gasdosing system, the volumetric dosing control was replaced with a system for the mass control of the introduced gas. Closing the system was considered to be suitable, as the water composition remained almost constant during the entire experiment. Improvements to the gas-dosing control and the closing of the system were carried out in the final phase of the pilot plant's adaptation. Further measurements were made in different seasons to test the seasonal influences on underground water's composition and the efficiency of the carbon dioxide supply.
Ključne besede: underground water, drinking water quality, pilot plant, carbonate equilibria, carbon dioxide, precipitation, scale
Objavljeno v DKUM: 05.06.2018; Ogledov: 1645; Prenosov: 79
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Opis: Many laboratory investigations of magnetic water treatment (MWT) for scale control explained the formation of less compact scales by raised portion of aragonite, which is needle-like and less adhesive than rhombohedral calcite crystals, while our experiment was conducted with tap water, which contains Mg+2 and Fe+2 ions in concentrations exceeding thresholds for calcite inhibition, common for major tap waters. MWT efficiency was evaluated by amounts of scale precipitated in boilers and pipes during three-weeks run of two parallel experimental lines-one with and another without magnetic treatment. All scales were identified by X-ray diffractometer to be aragonite,but in the case of magnetic treatment, scales occurred in much smaller amounts: the scale on heating copper-pipe spiral was 2.5-times thinnerdue to MWT and in zinc-coated steel pipe occurred as very thin powder-like coating, while in the line without the treatment abundant hard lining was formed. The scalesć morphology was observed by scanning electron microscope: the husks from both lines consisted of parallel distributed needles, but these crystals were about four times thinner in the case of MWT. The present work demonstrates that hard scale deposits can form even under conditions where aragonite precipitates predominantly, and that MWT can also affect the crystallization of this polymorph in a manner conducive to scaling control.
Ključne besede: water, magnetic water treatment, scale, aragonite, cristallization, water supply pipes
Objavljeno v DKUM: 01.06.2012; Ogledov: 2379; Prenosov: 114
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Ključne besede: kemijska tehnika, prenosni pojavi, karbonatno ravnotežje, demineralizacija vode, vodni kamen, eng, chemical engineering, transmission phenomenon, equilibrium of carbonate, deionization of water, scale
Objavljeno v DKUM: 11.12.2008; Ogledov: 3896; Prenosov: 451
Celotno besedilo (803,56 KB)