ABSTRACT
In this thesis, I have analyzed the importance role of ice slurry in our daily life and
the current development status of the vacuum ice slurry making equipment, compared
with other non-vacuum ice slurry making equipments’ respective advantages and
disadvantages comprehensively. Analyzed the issues which run with a high vacuum
degree that vacuum ice slurry making equipment have, and put forward the concept of
intermediary substances. It requires that the intermediary substances are soluble in
water, having a high soluble latent heat, and its boiling temperature is lower than water
at the same pressure.
This thesis proposed that use the intermediary substances added to the water to
reduce the vacuum degree that the vacuum ice slurry equipment needs. This paper used
the theory of the equilibrium of the chemical potential and combined with the phase
diagram of the solution to verify that the intermediary substances added to the vacuum
ice slurry making system can water down the system’s requirements on vacuum degree.
In order to verify the effects of intermediary substances, I chose ammonia as a
representative of the intermediary substances, and introduced the vacuum evaporation
experimental system’s design, selection and set up process.
Make sure that the ammonia with concentration of 26% and distilled water have the
same initial temperature, put them in the same vacuum environment, and then test their
temperature changes. Experiments show that in conditions of same initial temperature
and vacuum degree, the cooling rate of ammonia was significantly higher than distilled
water; the temperature’s drop range of ammonia was larger than distilled water; and the
ammonia generated ice crystals before distilled. This paper describes the ammonia
cooling characteristics with the several absolute pressure no less than 1kPa, 5kPa,
10kPa. Experiments show that with the decrease of vacuum degree, ammonia’s cooling
rate decreases, but still much faster than the distilled water; and formatted ice and the
absolute pressure of 1kPa. Experiments show that if adding ammonia to water, the
vacuum ice slurry system do not have to drop the pressure down to the pressure of
water’s triple point to generate ice crystals, have reduced the requirements on the
vacuum degree.
According to the experiments, this thesis has given out the improvements of the