Volume 5 Issue 2
Authors: Zaccheus O. Olaofe
Abstract: This article presents the comparisons of energy production predictions of a small-scale 40 kW wind turbine using an exponential smoothing technique and multilayer feed-forward neural network. For wind energy predictions, the developed mathematical model based on exponential smoothing was used to smoothen any seasonality arising in the time series data obtained at the site. This model was developed using three smoothing constant values of 0.20, 0.65, and 0.90, as well as a combination of a smoothing constant value of 0.90 with a seasonal adjustment factor for prediction of a small-scale wind turbine output for a period of 12 months. In addition, an energy model based on a multilayer feed-forward neural network was used to compute the energy generation of the turbine. The seasonally adjusted forecast model accurately predicted the wind energy output with the lowest forecast errors when compared to the chosen three smoothing constants. The energy forecasts obtained from the seasonal adjusted forecast model and multilayer feed-forward neural network were compared to the actual energy generation of the turbine at the considered tower height in terms of their forecast erroneous values.
Keywords: Time Series Data (TSD); Smoothing and Seasonal Factor; Exponential Smoothing; Feed-Forward Neural Network (FNN), Small-Scale Wind Turbine
Authors: L. M. Farag; H. K. Abd El-Hamid
Abstract: A simple mathematical model of heat balance was applied to a cement kiln plant with a precalciner to estimate the effect of using rice husk as a substitute fuel for natural gas on specific heat consumption. Effects of the husk ash on the characteristics of the raw mix and clinker of ordinary Portland cement were also evaluated. Referring to Egyptian kiln plants data, it was found that the weight of rice husk required to supply fuel heat in the precalciner represented about 11-13% of the raw mix weight and about 90% of the total fuel weight (natural gas + husk). Specific heat consumption increased by about 3.7%, and the amount of combustion flue gases increased by about 20% when natural gas was completely substituted by rice husk. The use of rice husk as a substitute fuel in a cement kiln plant was accompanied by a marked decrease of lime saturation factor of the raw mix, a drastic decrease of tricalcium silicate and an increase of dicalcium silicate in the clinker. This data can provide the basis for the formation of a new type of cement such as high belite cement. The raw mix design was adjusted using pyrite as a correcting factor to keep the characteristics of the raw mix and the clinker similar to the factory data.
Keywords: Alternative Fuel; Rice Husk; Natural Gas; Raw Mix Design; Clinker Mineral Composition; Raw Mix Parameters; Specific Heat Consumption