Sodium silicate-molten binary nitrate compounded heat-transfer heat-storage medium and its preparation method and use

Abstract

The invention discloses a sodium silicate-molten binary nitrate compounded heat-transfer heat-storage medium and its preparation method and use. The sodium silicate-molten binary nitrate compounded heat-transfer heat-storage medium is prepared by compounding a molten binary nitrate system and sodium silicate. The molten binary nitrate system mainly comprises potassium nitrate and sodium nitrate. The sodium silicate-molten binary nitrate compounded heat-transfer heat-storage medium has heat-transfer performances of the nitric acid molten salt, improves a safe work temperature upper limit of the system to 650 DEG C, and has a wide use temperature range and good thermal conductivity. The sodium silicate-molten binary nitrate compounded heat-transfer heat-storage medium has good heat absorption and heat-storage capability, solves the problem that the molten binary nitrate 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 binary nitric acid 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 nitrates, carbonates, sulfates, fluorides, chlorides, oxides, etc. [0003] Nitric acid molten salt system has a wide range of raw materials...

AI Technical Summary

Problems solved by technology

The ternary nitric acid molten salt system has a low melting point, which is ideal; but the upper limit of the working temperature is low

The working temperature range of the binary nitrate system is 260°C-565°C, and the upper limit temperature is ideal, but the melting point is too high, resulting in high maintenance costs when the clouds cover

However, calcium nitrate has poor thermal stability and is easy to decompose at high temperature.

[0005] Chinese patent application 00111406.9 discloses a LiNO 3 -KNO 3 -NaNO 3 -NaNO 2 system, its operating temperature range is 250°C-550°C, the upper limit operating temperature of this system is higher than the ternary nitrate system, reaching 550°C, but its lower limit operating temperature is also increased, resulting in increased maintenance costs when clouds are covered, and The addition of LiNO3 increases its corrosiveness and cost

[0009] So far, there is no report on adding water glass to binary nitric acid molten salt as a heat transfer and heat storage medium in the field of industrial energy storage and solar thermal power generation.

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