Natural Gas Intermittent Kiln for the Ceramic Industry: A Transient Thermal Analysis

Abstract

Drying and firing of ceramic products are processes that require high energy consumption. Making these processes more efficient can improve product quality, reduce processing time and energy consumption, and promote economic and environmental gains. In this sense, this work aims to quantify heat transfer in an intermittent ceramic kiln during the heating and cooling stages, with and without thermal insulation. All mathematical formulation is based on the first law of thermodynamics. From the results, we conclude that the greatest heat loss occurs by radiation in the sidewalls of the equipment, and that a considerable amount of energy is required to heat the sidewalls, base, and ceiling of the kiln. Further, with the use of thermal insulation, it was concluded that a high reduction in the heat lost through the sidewalls was achieved, thus providing a global energy gain of approximately 35% and a reduction in the maximum external surface temperature from 249.34 to 79.47 °C when compared to the kiln without thermal insulation, reducing the risks of work accidents and thermal discomfort when in operation.

Transient Thermal Analysis in an Intermittent Ceramic Kiln with Thermal Insulation: A Theoretical Approach

“…is paper presents thermal analyses in an intermittent ceramic kiln, operating with natural gas as fuel, illustrated in Figure 2. e dimensions of the kiln and the experimental procedure for monitoring external ambient and kiln temperatures are reported in previous work [28].…”

“…is methodology has been used in several works related to the most diverse areas of computational fluid dynamics [43][44][45][46][47][48]. e entire procedure for mesh convergence analysis is described in detail in Gomez et al [28].…”

“…where _ E st is the rate at which energy is stored in the kiln, q lost (base/ceiling) is the heat lost by the base/ceiling assembly of the kiln, and q lost sidewalls is the heat lost by the sidewalls of the kiln without thermal insulation. e calculation methodology for each heat transfer parameter in the kiln without thermal insulation is presented in detail in Gomez et al [28]. q lost insu is the heat lost by thermal insulation (equation (27)) and _ E st insu is the rate at which energy is stored in the thermal insulation, calculated according to equation (28).…”

“…e calculation methodology for each heat transfer parameter in the kiln without thermal insulation is presented in detail in Gomez et al [28]. q lost insu is the heat lost by thermal insulation (equation (27)) and _ E st insu is the rate at which energy is stored in the thermal insulation, calculated according to equation (28).…”

“…Gomez et al [28] quantified the heat transfers that occur in an intermittent ceramic kiln during the heating and cooling stages. Results indicate that the greatest heat loss occurs by radiation to the sidewalls of the equipment and that a considerable amount of energy is required to heat the base, ceiling, and sidewalls of the kiln.…”