# Estimation of the Energy Consumption of the Rice and Corn Drying Process in the Equatorial Zone
## 3 Results
### Rice Processing Plant
#### 3.1.3 Energy Valuation  
Table 3 presents the number of dryers evaluated in the first, second, and third categories of rice processing plants. Figure 11 presents a diagram of the energy consumption of a second and third category dryer. Figure 11 shows that the surrounding air is heated by a gas burner (temperature of flame between 200 and 600 \({}^{\circ}\)C). The extractor removes the hot air from the environment (130 \({}^{\circ}\)C and 170 \({}^{\circ}\)C) to enter the drying chamber. Having performed a brief analysis, it is evident that there is an oversizing of the extractor and thermal loss in the square ducts that connect to the drying chamber. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Canton** & **Number of Dryers Evaluated** & **Category** \\ \hline Daule & 13 & (1) First, (5) Second, (7) Third \\ Salitre & 8 & (3) Second, (5) Third \\ Santa Lucia & 6 & (1) First, (5) Second \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Number of dryers evaluated in the three cantons of the Guayas province. Figure 10: Shows two types of biomass dryers. (**a**) Double chamber dryer; on the left is the drying chamber and on the right is the combustion chamber. Brazilian technology, first-generation processing plant; (**b**) Handcrafted dryer with a drying chamber, combustion oven, ducts, and an exhaust fan in a second-generation processing plant. As an example, the rice dryer measurement results for a capacity of 909 kg are presented. Figure 12 shows that the chamber hot air temperature and speed are not uniform, causing the product to dry faster in one section than another. For more significant compression, in the rice dryer simulation, the observed flow is not turbulent in the entire chamber, due to the wind speed that initially carries at the entrance to the chamber (13 to 11 m/s). For this reason, it is necessary to place baffles in the post-chamber so that the hot air flow is distributing in the drying chamber. Product drying operation takes from 12 to 24 h. The operation consists of turning on the equipment to dry the product for 2 to 3 h, then the burner is turned off, and the product is allowed to cool for one hour, then an operator moves the rice for 20 min. Finally, the burner starts again, and the cycle continues. On the other hand, there are many setbacks in analysing energy consumption as the equipment does not have its corresponding information plates, this equipment being; extractors, motors, and fans. Therefore, the electricity consumption was estimated from their electrical bill, considering a 0.08 $/kWh reference cost. It should be noted that in rice processing plants, they do not only dry rice, they also peel the product. Therefore, the company energy cost is global. The actual energy consumption of drying and the power of the motors and extractors were estimated.  
Figure 11: Temperature and drying time (**a**) rice processing plants of the third category, (**b**) rice processing plants of the third category.  
For small drying centres, the LPG domestic tanks used for drying were considered. Since the domestic LPG is subsidized by the Ecuadorian government, its commercial price is $3 per LPG gas cylinder of 15 kg. Concerning the dryers that use biomass as fuel, taking, for example, a dryer with a capacity between 1800 to 2726 kg of wet rice after 12 h of drying, it requires 1140 kg/h of husk and generates approximately 560 kg of ash. Finally, it is necessary to indicate that 90% of the dryers evaluated do not have a control system to set the hot air operating temperature entering the drying chamber; therefore, the dry product loss occurs around 2 to 4% by burning it. Figure 13 shows a diagram of the biomass dryer of the first generation category. Figure 12: Drying chamber (**a**) dryer temperature measurements, (**b**) simulation of the hot airflow in the drying post-chamber. Table 4 shows the electricity, gas, biomass, and diesel consumption in rice processing plants.