Abstract |
The present thesis focuses on the design and construction of a pilot
prototype of a water recirculation unit with heat exchanger and cooling
tower as a model of the systems used in industry. This unit is build and
used for the study of the inhibitory ability of chemical additives on
sparingly salt formation, which constitute a very important problem on
industrial cooling systems, especially on their effect on deposition of
sparingly salts on heated surfaces.
Heat exchanger planning was realized using mass and energy balance.
The application of mass balance was realized under permanent (static)
conditions, whereas the application of energy balance was realized
under non-permanent (dynamic) conditions, as it happens in A real
industrial setting. Also, it was calculated the demanded power that the
pump must have for an ideal system function using a cooling tower that
was functioning in a “cross-flow” fashion for most efficient water
cooling.
The chemical additives that were used as inhibitors belong to two categories: phosphonic acids (2-phosphonobutane-1,2,4-tricarboxylic acid and bis(hexamethylene triaminepenta (methylenephosphonic acid))
and carboxylic-based polymers (carboxymethyl inulin family). The
carboxylic-based polymers are “green” additives since they are environmentally – friendly, non toxic and biodegradable.
At the present thesis experiments were carried out in the absence of inhibitors (control) so that we could we can compare the quantity and the quality of their effect on CaCO3 fouling and for each inhibitor separately. All inhibitors tested, showed inhibitory ability in CaCO3 formation. This conclusion is based on macroscopic observation (CaCO3 fouling) and on soluble Calcium measurements.
Finally, the role of temperature of the heat exchanger, the heating time
and the water flow within the unit were very important factors for CaCO3 fouling on the heated surface, considering the CaCO3 inverse solubility features.
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