Preparation And Study Nitratite Molten Salt Heat Storage Material

Fossil energy shortage and environmental pollution problems caused by the use of fossil fuel, which seriously restrict the development of the world economy. Solar energy as a near limitless clean energy was paid more attention by the world, including solar energy development and utilization of solar thermal power generation is the most important part. But the use of solar energy was restricted by alternating day and night, the seasons, the weather conditions change, so there is no continuity, intermittently. But the use of solar energy was restricted by alternating day and night, the seasons, the weather conditions change, so there is no continuity, intermittently. Heat storage material is appeared because it can store heat at solar radiation is strong and release heat at solar radiation is low. And heat storage technology and heat storage material has become a key factor in solar thermal power technology.Molten salt heat storage material has been extensively studied in heat storage material. The disadvantage of molten salt is high freezing point, which could easily lead to clogged pipes. Chemical resistance and high temperature stability which is the limiting factor is applied to solar thermal power generation. This paper is based on the study of potassium nitrate, sodium nitrate as the raw material,Using the mixed melting method preparation process, by adding expanded graphite(Expanded Graphite, referred to as EG). Observed thermal performance change of molten salt by adding the EG, tin(Sn) and nitric lithium. So as to effectively solve the problem of coagulation, chemical stability and high temperature corrosion problems.The results show that: expanded graphite can improve the thermal conductivity of the molten salt, 5% of the appropriate dosage quality; tin can add to the thermal conductivity, specific heat capacity has greatly improved, but poor compatibility, not much to add; nitrate lithium can effectively reduce the freezing point of the molten salt, but its deliquescence serious and expensive, can add the right amount. There is a good chemical compatibility between sodium nitrate, potassium nitrate, lithium nitrate, and expanded graphite. Below 600 ℃ they don’t react with each other, without generating a new phase and meet the requirements of the heat storage material.