Ali Motevali; S. Jafar Hashemi; Ebrahim Taghinejad
Abstract
Now day, global warming is too considerable due to consumption of fossil fuels. Use of fossil fuels in power plants for electricity generates has the largest portion of greenhouse gas and emissions in the world. Agricultural section has the outstanding contribution in electricity industry; furthermore ...
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Now day, global warming is too considerable due to consumption of fossil fuels. Use of fossil fuels in power plants for electricity generates has the largest portion of greenhouse gas and emissions in the world. Agricultural section has the outstanding contribution in electricity industry; furthermore the processing and drying of agricultural products have the highest consumption energy. In the current research, the parameters of energy, the environment (global warming) and social costs of drying of apples slices at three temperatures 45, 55 and 65° C and the air velocity 0.5 m/s for different pretreatment of osmotic, ultrasound, blanching and microwave (each pretreatment at three levels) were evaluated. Result shown that the amount of time, energy consumption, specific energy and heat consumption decreased with increasing temperature and using different pretreatments as compared to control treatment. Also, energy, drying and thermal efficiency, increased with increasing air temperature. The highest amounts of energy and drying efficiency were obtained %5.04 and %5.62, respectively for microwave pretreatment involving 360 W power and 2.5 min at 65° C temperature. Normal treatment with 45°C temperature gave the lowest value of efficiency energy (%2.27) and drying (%2.38). Results revealed that the highest and lowest greenhouse gas for the withdrawal one kilogram of water from apple slices was produced 21.19 and 9.37 kgCO2, 10.05×10-4 and 4.45×10-4 kgCH4, 2.01×10-4 and 0.89×10-4 kgNO2 respectively. Also, the highest and lowest social costs for leaving one kg of water from apple slices was obtained 34927.60 and 15449.04 Rials for steam power plant, 35263.45 and 15597.59 Rials for power plant and 30561.66 and 13517.91 Rials for combined cycle power plant, respectively.
E. Taghinejad
Abstract
Parboiling is a hydrothermal treatment and it consists of 3 steps: soaking, steaming and drying of paddy. In this research RSM and central composite design was used for optimization of parboiling indicators (soaking temperature and steaming time). After soaking temperature of (55, 60, 65, 70 and 75 oC) ...
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Parboiling is a hydrothermal treatment and it consists of 3 steps: soaking, steaming and drying of paddy. In this research RSM and central composite design was used for optimization of parboiling indicators (soaking temperature and steaming time). After soaking temperature of (55, 60, 65, 70 and 75 oC) and steaming time of (2, 4, 6, 8 and 10 min), the samples were dried for three days in the shade to a final moisture content of 11±1% (w.b.). Using multiple regression analysis a quadratic polynomial equation was developed for each response. Analysis of variance (ANOVA) was performed to check the adequacy and accuracy of the fitted models. The results showed that the effects of soaking temperature and steaming time were found to be significant (p<0.01) with regards to head rice yield. Results also showed that, soaking temperature and steaming time were the most important variables which affect the head rice yield, respectively. Based on developed modeles, optimum conditions for the maximum head rice yield of (66.67%), were achieved at soaking temperature of 64.93oC and steaming time of 6.67 min.
