Study On Heat Pump Through-flow Drying System Of Expended Fish Feed

Aquaculture is one of the basic industries for the development of the national economy,to a certain extent,the types and production techniques restrict the development of aquaculture,and the drying process affects the energy consumption and product quality of feed production directly.In recent years,expanded feed has developed rapidly due to its good water suspension,high feeding utilization rate,and low water pollution.and the traditional drying process still uses the coal-fired fuel method.The drying process consumes large energy and the product quality is low.However,heat pumps have developed rapidly with the advantages of mild drying,good product quality,and high economic benefits.Therefore,the article studies the application of the heat pump system to the drying process of the expanded fish feed in order to achieve better economic and energy-saving effects.The article analyzes the drying process of typical materials,clarifies the basic principle of moisture migration during the drying process and the drying characteristics of materials at different stages,and defines the drying characteristics of porous media material in the throughflow drying process.Compare and analyze the performance of different heat pump systems,briefly analyze the factors that affect the performance of the heat pump system,and conduct thermodynamic analysis on the drying cycle and the refrigeration cycle.In order to determine the characteristic curve of the expanded fish feed through-flow drying process,design a through-flow drying experimental device and conclud that the supply air temperature and the thickness of the material layer under the minimum fluidization speed condition are the main factors affecting the feed drying process;the supply air temperature has a great influence on the drying curve of feed,under the condition of low relative humidity,the change of the relative humidity has little effect on the drying curve.Through data fitting,it is determined that the Page model is a mathematical model of expanded fish feed through-flow drying.According to the drying model,analysis the performance of the feed drying process under different drying processes.When the effective utilization rate of air is used as an indicator,the three-process drying performance better,when SMER and COP are used as indicators,compared with the three-process,the SMER value of the fourth process is reduced by 9.8%,and the COP value is reduced by 4.5%.Comprehensive analysis shows that the drying process is better when it is a three-process.According to the influence of the basic structural of the drying chamber on the uniformity of the indoor airflow,establish an airflow model to analyze the uniformity of the indoor airflow distribution.It is concluded that while keeping the air outlet area constant,increasing the number of air outlets can improve the airflow uniformity;changing the aspect ratio of the air outlet has little effect on the airflow distribution in the drying chamber;the change in the height of the air inlet and outlet mainly affects the speed distribution of the air inlet surface of the adjacent feed layer.when the height of the air inlet and outlet exceeds 500 mm,continue to increase the height has little effect on the airflow distribution in the drying chamber;the installation of a wind baffle in the air outlet section can reduce the height of the air outlet section under the condition of ensuring the uniformity of the airflow.Under the experimental conditions,when the height of the air inlet section is 500 mm,the height of the air outlet section is 300 mm,the length of the baffle is 3600 mm,and the width is 1440 mm,the airflow uniformity in the drying chamber is better.According to the requirement of equipment drying capacity in the actual production process,LMS AMEsim software is used to model the heat pump unit,establish a simulation model of the heat pump unit,and analyze the factors that affect the performance of the heat pump unit.Determine the influence of each factor on the performance of the unit through orthogonal experiments,and optimize the design of each component parameter,and it is concluded that the system energy efficiency ratio COP can be increased by 11.0% under the optimized parameter conditions;based on the heat pump unit model and the basic structure of the drying chamber,establish the basic model of expanded fish feed heat pump through-flow drying,determine the basic size parameters of the model.The system energy efficiency ratio is5.5,and the unit energy consumption and dehumidification capacity is 3.3,it can achieve the drying of the expanded fish feed and achieve better energy-saving effects.