Water glass composite carbonate molten salt heat transfer heat storage medium and its preparation method and application

Abstract

The invention discloses a sodium silicate-molten carbonate composite heat-transfer heat-storage medium and its preparation method and use. The sodium silicate-molten carbonate composite heat-transfer heat-storage medium is obtained by compounding a molten carbonate system and sodium silicate. The molten carbonate system mainly comprises potassium carbonate and sodium carbonate. The sodium silicate composite carbonic acid molten salt heat-transfer heat-storage medium has heat-transfer performances of the molten carbonate, improves a safe work temperature upper limit to 840-850 DEG C, and has a wide use temperature range and good heat stability. The sodium silicate-molten carbonate composite heat-transfer heat-storage medium has large phase-change latent heat and high energy storage density, reduces requirements on a heat-storage system size and energy and has a high energy utilization rate. The sodium silicate-molten carbonate composite heat-transfer heat-storage medium has good heat absorption and heat-storage capability, obviously improves a heat conduction coefficient, improves heat conduction performances, solves the problem that the molten carbonate has poor thermal conductivity and easily produces local overheating, and can be widely used in the technical field of solar photo-thermal power generating.

Description

technical field [0001] The invention relates to the technical field of heat storage and transfer, in particular to a water glass composite carbonate molten salt heat transfer heat storage medium and a preparation method and application thereof. Background technique [0002] In industrial energy storage and solar thermal power generation technologies, the heat storage and heat transfer media currently used mainly include air, water, heat transfer oil, molten salt, sodium and aluminum and other metals. Molten salt has become a potential heat transfer and heat storage medium in solar thermal power generation technology due to its wide operating temperature range, low vapor pressure, low viscosity, good stability, and low cost. A relatively mature heat transfer and heat storage medium. High-temperature molten salts mainly include carbonates, nitrates, sulfates, fluorides, chlorides, oxides, etc. Solid-liquid phase change high-temperature phase change materials, mainly high-tem...

AI Technical Summary

Problems solved by technology

[0003] The mixed nitric acid molten salt system has the advantages of low melting point, good thermal stability, and low corrosion to container and pipeline materials. However, nitric acid molten salt is easy to decompose at high temperature, and its upper limit temperature generally does not exceed 600 ° C, which is not suitable for high temperature applications.

The Chinese patent application number 200810027638.9 discloses a carbonate molten salt system (Na 2 CO 3 ,K 2 CO 3 , NaCl, KCl), the upper limit temperature is as high as 800°C, which can well meet the requirements of high-temperature heat transfer and heat storage of solar energy, which is ideal, but the melting point of 567°C makes the lower limit temperature too high, and the maintenance cost is too high due to energy consumption and heat preservation

Chinese patent 200910037348.7 discloses a lithium carbonate molten salt system (Na 2 CO 3 ,K 2 CO 3 ,NaCl,Li 2 CO 3 ), the additives sodium chloride and lithium carbonate used effectively maintain the high safe use temperature upper limit of the system, but LiNO 3 The addition of it increases its corrosiveness and costs

[0006] So far, there is no report on adding water glass to carbonate molten salt as a heat transfer and heat storage medium in the field of industrial energy storage and solar thermal power generation.

Images