Pepper Intermittent Hot Air Drying Pilot Study

The Chinese prickly ash is popular as a kind of medicinal and edible plant and is one of the eight Chinese traditional sauces, so it is of much economic value. Presently, with the enhancement of people's living standard, the consumption of prickly ash oil, prickly powder and the fast food is increasing day by day, of which the primary material is the Chinese prickly ash, therefore the consumption amount of dried prickly ash is increasing. But at present, the methods applied in drying Chinese prickly ash are hot-curing drying, fired-baking drying and artificial drying. The period of air-curing drying is long and it is affected by the weather easily, it is hard to control the temperature of fired-baking drying and the oil cells are easily to be broken, which affects the quality of dried Chinese prickly ash obviously, the artificial drying mainly is hot-air drying. But now, the experiment on the technology of drying Chinese prickly ash by hot-air is very few in the world. Formal experiments ignored the influence of two factors the afterheat and the layer thickness. If the two factors have much impact on the results, their drying process should be improved. Whether the two factors have impact on the drying results, there is no experiment to prove it so far. The afterheat is relative to the time of power being off which is intermittent time, the more the afterheat, the longer the time of power being off is, or it is shorter, so the intermittent time is corresponding to the intensity of afterheat in this experiment. Therefore, this paper substitutes the intermittent time for the afterheat and makes research on the Chinese prickly ash hot-air drying comprehensively and systematically. The two factors the afterheat and layer thickness are thought and there are two methods for the experiment, which are intermittent hot-air drying with constant temperature and intermittent hot-air drying with different temperatures by stages.The factors of this experiment in this paper are temperature, windy speed, layer thickness intervals and the time of heating. This experiment is according to the orthogonal experiment design form L16 (4~5) .Through the experiment, the Chinese prickly ash drying curve and the drying rate curve have been drawn, from the curves, we can see that the whole drying process is stable, the time of accelerating and reducing speed is comparatively less than the time of constant speed. The rate reduces gradually with the time extension. This paper has analyzed the impact of the temperature, windy speed, layer thickness and intermittent time on the Chinese prickly ash quality, drying energy consumption, drying time and general effect by range analysis. From the analyzing result, in the intermittent hot-air drying with constant temperature, what mainly have much effect on the Chinese prickly ash quality, drying energy consumption and drying time are temperature, layer thickness and windy speed, what factors affect the general effect are layer thickness and heating time, in the intermittent hot-air drying with different temperatures by stages, what mainly have much effect on the Chinese prickly ash quality, drying energy consumption and drying time are temperature, layer thickness and windy speed , what factors affect the general effect are layer thickness and windy speed. The layer thickness has much effect on the results of drying Chinese prickly ash, which should not be ignored, the effect of intermittence is the least, then it is found that the better process of intermittent hot-air drying with constant temperature and intermittent hot-air drying with different temperatures by stages. Comparing the two drying methods, the conclusion is that the quality and the general effect of intermittent hot-air drying with constant temperature are better than intermittent hot-air drying with different temperatures by stages, the effect on the other two index is almost the same. To get the equation of factors and index, this paper makes the analysis of variance and multiple linear regression analysis for intermittent hot-air drying with constant temperature and gets the regression equation, which prove that the index the quality of the dried Chinese prickly ash, drying energy consumption, drying time and general effect are linear with temperature, windy speed, layer thickness intervals and the time of heating obviously.