Development And Application Of Cold Storage Of Fresh Agricultural Products

The improvement of the living standard of the residents has led to the increasing demand for fresh agricultural products.In this paper,the short-distance and lowtemperature transportation of small-scale fresh agricultural products and perishable food products were focused.The special cooler and coolant for fresh agricultural products were designed,and the research and development of a whole set of fresh agricultural products cold chain logistics system were developed,which aimed at providing effective and feasible program for fresh agricultural products of cold chain and low-temperature transport.The specific research contents are as follows:1.Primary selection and performance optimization of coolant for fresh agricultural products(1)The performance and economy of ice,dry ice and gel phase change refrigerant coolant were compared comprehensively,the use of gel phase change refrigerant as a cold source of passive cooler of raw agricultural products was determined.(2)The mannitol and potassium chloride were selected as the main raw materials for the phase change coolant according to the literatures.The formulation experiments of the coolant was conducted in six different ratios and three groups of flow modification test,the mannitol with concentration of 0.3 mol / L and the potassium chloride of 0.1 mol / L were mixed by volume ratio of 1:1,the temperature of phase transition reached-4.65 ?;the latent heat of phase change was 308.1642 J / g;the initial work of formulation of coolant was completed.(3)At the same time,the coolant of the cold storage of the fresh agricultural products developed in this project was better than that of the similar products in the market after compared with nine coolants commercially available.2.Development and Design of Cold Storage Box for Fresh Agricultural Products(1)Design and calculation of the cold load of the box,a 8L small and passive cooler only need 1300 KJ cold load which can guarantee the requirements of cargo in 48 h low temperature transportation,it was confirmed that the coolant used in this subject could meet the needs of cold chain transportation(2)Using Ansys software to analyze the capacity of insulation and storage of the passive cooler in fresh agricultural products,the time of cold preservation of cold storage was 3980 min,and when the proportion of the coolant and the cargo was above 3: 8,a better insulation effect could be gained,the time of cold preservation could reach more than 21 h.From the analysis of insulation effect and economy,during the actual use of passive cooler,the placement scale of coolant and cargo in 1: 3 ~ 1: 2 was suitable,and some high value-added goods,which are not easily to store and transport,should be placed in the ratio of 1: 1 to 2: 1.3.Effect experiment of fresh production of passive cooler in fresh agricultural productsThe perishable fruit was taken as trail,for example strawberry pre-cooled to 0 ?,the passive cooler developed for fresh agricultural products in this subject was used as the carrier,the strawberry and coolant were put into the cooler at the mass ratio of 1: 1,and the coolant was fixed around the inner wall of the cooler.Four storage conditions,which are the developed coolant + the developed cooler(CY1),the developed coolant + the commercially available cooler(CY2),the commercially available coolant + the commercially available cooler(CY3)and ice cubes + foam box(CY4),were prepared and the effects of strawberry on preservation after 60 h were analysed.After 63.8h,the decay indexes of the four groups were 13.0%,15.8%,19.6% and 30.1%.By measuring the mean temperature change in the cooler,the decay index,the weight loss rate and the hardness of the strawberry,it was clear that the indexes of the strawberry in the control group of the ice foam box were significantly changed with the increase of the storage time,while indicators of the cooler developed in this subject for the fresh agricultural products were better than similar products commercially available,therefore,the cooler could be widely used in cold chain low-temperature transportation for fresh agricultural products.4.Design of Matching System for Cold Chain of Fresh Agricultural ProductsTo improve the fresh agricultural products cold chain transport system,the low-temperature storage system was designed for the development of cooler of fresh agricultural products around the subject.By converting a small-scale warehouse into a cold chain special cold storage for fresh agricultural products,the pre-cooling of goods and the charging process of cooler have been achieved,Through the design and calculation,the capacity of cold storage is 201.92 t,the cooling load is 594.91 KW.