Drying performance of manure drying system with waste heat of poultry house in summer

A large amount of poultry manure is produced yearly in China, which has become a tremendous pressure on the environment when it cannot be utilized as resources. Improper or untimely handling method of manure can result in massive discharge of ammonia, which is a major source of air pollution. Manure can also serve as a breeding ground for pathogenic microorganisms as well as a medium for disease transmission among birds. It is necessary to subject poultry manure to suitable treatments including storage and handling in order to minimize the risk of disease transmission and environmental pollution. The environmental problems can be eliminated by decreasing the moisture ratio of poultry manure to minimize its decomposition rate and the dried poultry manure can be utilized as a raw material to produce organic fertilizer. Thermal convective drying has been proven to be an effective method to remove moisture from poultry manure. Using waste heat of poultry house to dry poultry manure refered to the thermal drying method of removing water in poultry manure, which was mainly characterized by low energy consumption. This drying method could be a proper method to deal with poultry manure in China. This paper mainly expounded the working principle of heat recovery of exhaust air from poultry house. Based on the principle of heat balance in poultry house, this paper explored heat calculation methods in the process of poultry manure drying, and ventilation methods for drying poultry manure in summer were designed. In the end, the application effect of the poultry manure drying system installed in Yingcheng was tested. The results showed that the drying efficiency of drying equipment varied greatly under different weather conditions in summer. Under the rainy weather, the waste heat of poultry house can meet the heat demand of reducing the water content of poultry manure to below 30% within 48 hours. In sunny weather, when the waste air from poultry house mixed with ambient air, it took about 28 hours to reduce the water of poultry manure, the end water content was decreased to 28%, which was 20 hours shorter than under rainy weather. In sunny weather, the enthalpy of ambient air decreased after it is discharged from the poultry house because of the wet curtain, at this time, if the ambient air can be used to dry poultry manure directly, and the drying rate will be improved. The sunny days in southern China are more abundant solar radiation in summer, hot ambient air is a suitable heat sources to dry poultry manure. Using hot ambient air can also solve the problem of excessive humidity in exhaust air from poultry house. Finally, according to the test results, the control scheme of reasonable utilization of exhaust air from poultry house and ambient air was proposed. The results provide an analytical reference to improve poultry manure drying efficiency and explore the ways of energy saving drying, as well as provide a reference to design the poultry manure drying process system.