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Clay drying is one of the most important steps in the construction materials industry. Due to its high-energy requirement, clay drying is one of the most energy-consuming processes contributing to greenhouse gas emissions, motivating the search for strategies to increase the energy efficiency of the process. The process involves several operating variables whose historical records can generate a large amount of data, which can be organized and analyzed efficiently using data mining techniques (DMT). In this paper, the performance variables of a material-industry rotary dryer were identified and analyzed. A cluster analysis was performed using the Ward's classification method with 1729 operating data, identifying the kind of materials processed and the operating configurations. A linear regression model was constructed using the RRELIEFF feature selection algorithm in Orange: Data Mining Toolbox in Python. The main thermal-energy-consumption variables were the production rate, power, inlet gas temperature, and product moisture delta. These four variables represent the dryer's specific energy consumption index ( I c ) more suitably than the classic Energy Vs Production model. Consequently, it was established that a global-aeration-factor reduction could improve the process efficiency by 7% to 10% at the average production rate. [ABSTRACT FROM AUTHOR]

The global energy demand enhances the environmental and operational benefits of natural gas as an energy alternative, due to its composition, mainly methane (CH4), it has low polluting emissions and benefits in energy and combustion systems. In the present work, the laminar burning velocity of methane was determined numerically and experimentally at two pressure conditions, 0.85 atm and 0.98 atm, corresponding to the city of Medellín and Caucasia, respectively, located in Colombia. The environmental conditions were 0.85 atm, 0.98 atm, and 295 ± 1 K. The simulations and experimental measurements were carried out for different equivalence relations. Experimental laminar burning velocities were determined using the burner method and spontaneous chemiluminescence technique, flames were generated using burners with contoured rectangular ports to maintain laminar Reynolds numbers for the equivalence ratios under study and to reduce the effects of stretch and curvature in the direction of the burner's axis. In general, the laminar burning velocity fits well with the numerical results. With the results obtained, a correlation is proposed that relates the laminar burning velocity with the effects of pressure, in the form SL = aPb, where a and b are model constants. Sensitivity analysis was performed using the GRI-Mech 3.0 mechanism which showed that the most sensitive reaction was H+O2 = O+OH (R38). Additionally, it was found that the reactions H+CH3 (+M) = CH4 (+M) (R52), 2CH3 (+M) = C2H6 (+M) (R158), and O+CH3 = H+CH2O (R10) dominate the consumption of CH3 which is an important radical in the oxidation of methane, this analysis is carried out for equivalence ratios of 0.8 and 1.0, and atmospheric pressures of 0.85 atm and 0.98 atm. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study of the characteristic parameters of the surface-stabilized combustion of a confined porous media burner with premixed methane/air flames. Parameters such as the stability range, emissions, and temperature profile of the confined porous medium were evaluated using a burner with geometric features that resulted in gas recirculation due to backward-facing step flows. An analysis of the flame morphology using the OH-planar laser-induced fluorescence technique was also conducted to determine the flame height with respect to the porous medium surface. The results show that the confinement causes gas recirculation, which displaces the flame downstream. Correspondingly, the confined/unconfined condition affects the heat transfer regime, which is observed in the variation of the combustion stability range and the temperature profile within the porous medium. The experiments show that for the confined condition, the porous medium temperature profiles did not vary significantly when the specific power (W/m2) increased for a fixed equivalence ratio (ϕ = 0.70). [ABSTRACT FROM AUTHOR]