Session: 16-02-01: Poster Session: NSF Research Experience for Undergraduates (REU)

Paper Number: 77076

Start Time: Wednesday, 02:25 PM

77076 - Electric Redesign of Wastewater Evaporators Using Porous Carbon Material to Minimize Heat Loss During Evaporation 

Currently, evaporation is one of the methods used to treat and dispose of wastewater. Further, many industrial plants rely on burning fossil fuels to heat the wastewater for evaporation. Recently, a variety of solar-powered evaporation methods have been investigated. One technology uses porous material to absorb thermal energy and insulate the heat on the surface of the water to allow for an air-water evaporation interface. This insulation, in turn, minimizes the heat dissipated to the bulk water and saves energy; however, wastewater evaporators that are entirely powered by solar energy have drawbacks. For instance, solar energy water evaporators require significantly more area than existing natural gas or steam-powered wastewater evaporators. Second, solar energy water evaporators have a much slower evaporation rate than natural gas or steam-powered evaporators. This makes it difficult for solar water evaporators to replace the majority of existing wastewater evaporators. Similarly, most of the existing wastewater evaporators found in industries today are fossil fuel-powered which is not sustainable. This paper presented an electric water interface evaporator design powered by a heating element. To minimize heat loss due to radiation, an insulated acrylic container was used. Further, porous heat insulating material was added underneath the heating element to insulate the heat at the upper region of the volume and minimize the heat dissipated to the bulk water. Additionally, the heating element insulated by the porous material was also tested under 1.2 sun conditions using a sun solar thermal energy simulator to increase the evaporation rate even further. Evaporation increased by 38.9 percent when 1.5 centimeters thick 100 pores per inch porous carbon foam was placed underneath the electric heating element. The increase in evaporation is due to the porous carbon foam’s thermally insulating characteristic. To start, the carbon foam was most effective when the water began to boil and convection became very apparent. This is because the carbon foam’s thermal insulation minimized the convection currents and isolated the heat in the upper region of the water. When the water was not boiling, the porous foam material underneath the heating element did not cause a significant difference because the convection currents and the movement of liquid were not as present. Ultimately, the redesign of the industrial evaporator in this study and the incorporation of porous material provided a sustainable and more efficient method for evaporating water. These findings can be implemented into existing industrial wastewater evaporators to increase their evaporation rate further. 

Presenting Author: Abdel Zaro Tennessee Technical University

Authors:

Abdel Zaro Tennessee Technical University
Divya Jaladi Tennessee Technical University
Ethan Languri Tennessee Technical University