Exergoeconomic Analysis of Corn Drying in a Novel Industrial Drying System

Abstract

The improvement of the design and operation of energy conversion systems is a theme of global concern. As an energy intensive operation, industrial agricultural product drying has also attracted significant attention in recent years. Taking a novel industrial corn drying system with drying capacity of 5.5 t/h as a study case, based on existing exergoeconomic and exergetic analysis methodology, the present work investigated the exergetic and economic performance of the drying system and identified its energy use deficiencies. The results showed that the average drying rate for corn drying in the system is 1.98 gwater/gdry matter h. The average exergy rate for dehydrating the moisture from the corn kernel is 345.22 kW and the exergy efficiency of the drying chamber ranges from 14.81% to 40.10%. The average cost of producing 1 GJ exergy for removing water from wet corn kernels is USD 25.971, while the average cost of removing 1 kg water is USD 0.159. These results might help to further understand the drying process from the exergoeconomic perspective and aid formulation of a scientific index for agricultural product industrial drying. Additionally, the results also indicated that, from an energy perspective, the combustion chamber should be firstly optimized, while the drying chamber should be given priority from the exergoeconomics perspective. The main results would be helpful for further optimizing the drying process from both energetic and economic perspectives and provide new thinking about agricultural product industrial drying from the perspective of exergoeconomics.

Study on the Variable-Temperature Drying Process of Corn Drying in an Industrial Corn-Drying System Equipped with a Self-Adaptive Control Heat Exchanger

“…In the present work, the Mc was measured at 30 min intervals, and the measured Mc was used to calculate the DR; the variations in Mc and DR with drying time t for different α are depicted in Figure 3; as can be seen from the figure, over the six drying cycles of the drying process, the Mc gradually decreases with the increase of t for different α. It can be seen from the variation trends of DR that the DR for the different α in the first cycle obtained the maximum values, which might be due to the fact that the evaporated water in this period could be regarded as free water, and the dehydration characteristic could be summarized as free water evaporation [21]; thus, moisture was quickly removed from the corn. Moreover, it also can be seen from Figure 3 that in the first drying cycle, the DR under α of 45 • , 60 • , 75 • and 90 • were similar and obviously higher than that of the others.…”

“…• m coal is the inlet mass rate of the coal, kg/s; q LHV is the low thermal value of the coal, q LHV = 4500 kcal/kg [21];…”

“…where the S FGP is the cross-sectional area of the FGP, m 2 ; ρ N is the density of the flue gas under standard pressure, kg/m 3 ; B a is the atmospheric pressure, Pa; p s is the hydrostatic pressure in the FGP, Pa. The enthalpy of the flue gas throughout the whole work can be determined by the following Equations (6)-(8) [21][22][23]:…”

“…where ρ a and ρ da are the density of the air and dry air, respectively, kg/m 3 ; v a is the velocity of the air, m/s; s a is the area of the air-flow path, m 2 ; X is the absolute humidity of the air, kg water /kg dryair ; R v is the gas constant of saturated water vapor, kJ•kg −1 •K −1 ; R a is the gas constant of dry air, kJ•kg −1 •K −1 ; T abs is the absolute temperature, K. The enthalpy of the air (h air ) throughout the whole manuscript can be determined by the following Equation 14 [21,26]:…”

A Preliminary Study of Chemically Preserved and High-Moisture Whole Maize (Zea mays L.) Usage in Pekin Duck Nutrition: Effect on Growth Performance and Selected Internal Organ Traits

“…In addition to the growth performance results, as well as the effects of whole maize on GIT development and physiological reactions, from a practical point of view, the implementation of the chemical preservation of whole maize grains has a beneficial impact on reducing production costs. It is well-documented that the drying process of grains is a highly energy-consuming operation that may expend 10–25% of the national energy use each year [ 18 ]. The heat-drying of maize after harvesting consumes 30–50% of all costs of grain preparation in Poland.…”