Energy Conservation Study On Preparation Process Of Fluidized Ice For Cold Chain Logistics By Seawater Pretreatment

Fluidized ice has many advantages owning for small ice crystals,rounded particles and easy availability.It can quickly lower the temperature of aquatic products and does not pierce the skin of aquatic products,which has broad application prospects in cold chain logistics.Through the current research of fluidized ice both at home and abroad,we find that there do exist problems like large supercooling degree and long ice formation time in the process of preparing fluidized ice,which lead to large energy consumption of the ice machine and hinder the application of fluidized ice.Therefore,it is necessary to explore ways to reduce the ice energy consumption of ice-producing mechanism.In this paper,the seawater pretreatment is used to reduce the degree of supercooling and shorten the ice formation time.The specific work is as follows:1.Set up an experimental platform.This paper briefly introduces the ice-producing principle of seawater fluidized ice and the equipment used to build the experimental platform,and the experiment of producing seawater fluidized ice was carried out to ensure that the temperature and time data in the ice-producing process can be accurately collected,which has provided a guarantee for the following experimental research;2.Propose a scheme for pre-treating seawater by adding ice crystals.Pure water and seawater were used as research objects.Fluidized ice was prepared by adding ice crystals with different mass fractions.The experimental results showed that 30% ice crystals were added to pure water and seawater to prepare fluidized ice,and the degree of supercooling was reduced.At 2.4? and 4.1?,the initial crystallization time was reduced by 145 s and 265 s.It can be seen that the addition of ice crystals to pretreat seawater can effectively reduce the degree of supercooling and shorten the ice formation time;3.Nano-chitosan was added as a nucleating agent to pretreat seawater.Taking seawater as the research object,the fluidized ice was prepared by adding nano-scale chitosan with different particle size and concentration.The experimental results show that the concentration of 0.05% of 400 nm chitosan can eliminate the supercooling degree of seawater by 6.9? and initiate crystallization.The time is reduced by 80.0 s.As the concentration and particle size of nano-scale chitosan increase,the degree of supercooling and ice formation of seawater decreases continuously;4.Seawater is pretreated by condensation recovery system.The low-temperature cold seawater,mixed with the seawater for prepare fluidized ice,is used for pre-cooling;In order to meet the requirements of equipment,the low-temperature copper tubes of concentrated brine are added,and the cold seawater is used for refrigerant cooling.By applying the above two methods,we have calculated the energy-conservation efficiency and found that the precooled seawater temperature decreases by 11.4?,the energy-conservation amount is 506.6 kW,and the ice-content rate of fluidized ice increases from 25% to 44%.