Mixed molten salt as heat transfer and storage medium low in melting point

A technology of mixing molten salt and heat storage medium, which is applied in the field of physical heat transfer and energy storage in high-tech, can solve the problems of inability to provide thermal properties, general thermal stability, and high melting point, so as to simplify the initial operation procedure and increase safety and stability performance, and the effect of improving power generation efficiency

Active Publication Date: 2013-05-01
河北井矿新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Currently available molten salt formulations still have high melting point, general t

Method used

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  • Mixed molten salt as heat transfer and storage medium low in melting point
  • Mixed molten salt as heat transfer and storage medium low in melting point
  • Mixed molten salt as heat transfer and storage medium low in melting point

Examples

Experimental program
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Effect test

Embodiment 1

[0036] This mixed molten salt is composed of 10wt% calcium nitrate, 60wt% potassium nitrate, 20wt% sodium nitrate, and 10wt% sodium nitrite. Through DSC (differential scanning calorimetry) analysis, its melting point is 130.2°C, According to TG (thermogravimetric technique) analysis, its decomposition temperature is 656.6°C. likefigure 1 Shown is the DSC curve for this sample. figure 2 Shown is the TG curve for this sample.

[0037] Compared with Solar Salt, the melting point of this formula is lowered by nearly 90°C, and compared with Hitec salt, the melting point of this formula is lowered by nearly 15°C, while the decomposition temperature is as high as above 650°C, which has a wider use temperature range.

Embodiment 2

[0039] This mixed molten salt is composed of 10wt% calcium nitrate, 70wt% potassium nitrate, 10wt% sodium nitrate, and 10wt% sodium nitrite. Through DSC (differential scanning calorimetry) test and analysis, its melting point is 129.0°C, Compared with Solar Salt, the melting point of this formula is lowered by nearly 90°C, and compared with Hitec salt, the melting point of this formula is lowered by nearly 15°C, while the decomposition temperature is as high as above 680°C, which has a wider use temperature range.

[0040] Secondly, in order to further reduce the melting point of the mixed molten salt, the present invention replaces the sodium nitrite component with lithium nitrate to prepare 16 kinds of quaternary mixed nitrates, and the specific operation method is the same as above. After a lot of experimental analysis, two formulations of molten salt were finally selected.

Embodiment 3

[0042] This mixed molten salt is composed of 20wt% calcium nitrate, 50wt% potassium nitrate, 10wt% sodium nitrate, and 20wt% lithium nitrate. Through DSC (differential scanning calorimetry) test and analysis, its melting point is 82.2 ° C. Heavy technology) analysis, its decomposition temperature is 604.9 ℃. like image 3 Shown is the DSC curve for this sample. Figure 4 Shown is the TG curve for this sample.

[0043] Compared with Solar Salt, the melting point of this formula is lowered by nearly 130°C, and compared with Hitec salt, the melting point of this formula is lowered by nearly 60°C, while the decomposition temperature is as high as above 600°C, which has a wider use temperature range.

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Abstract

The invention relates to a formula of a mixed molten salt for medium-high temperature heat transfer and storage, and belongs to the physical heat transfer and energy storage technology in innovative and high technologies. The mixed molten salt comprises components in a ratio as follows: 10wt% of calcium nitrate, 60-70 wt% of potassium nitrate, 10-20 wt% sodium nitrate and 10wt% of sodium nitrite; the melting point of the mixed molten salt is about 130 DEG C, which is reduced by nearly 90 DEG C relative to solar salt and is reduced by about 15 DEG C relative to Hitec salt; and the thermal decomposition temperature thereof reaches above 650 DEG C. Sodium nitrate in the molten salt is changed into lithium nitrate, and the specific component ratio is as follows: 18-20wt% of calcium nitrate, 50-55 wt% of potassium nitrate, 9-10 wt% sodium nitrate and 18-20wt% of sodium lithium nitrate; after the component ratio is changed, the melting point of the mixed molten salt is about 90 DEG C, which is reduced by nearly 130 DEG C relative to the solar salt and is reduced by about 50 DEG C relative to the Hitec salt; and the thermal decomposition temperature thereof reaches above 600 DEG C. 10wt% of sodium carbonate is added continuously, then the melting point is raised to about 110 DEG C, while the decomposition temperature is raised by nearly 20 DEG C.

Description

Technical field: [0001] The invention relates to a formula of mixed molten salt used for medium-high temperature heat transfer and heat storage, which belongs to the high-tech physical heat transfer and energy storage technology. Background technique: [0002] Since solar thermal power generation can be combined with low-cost large-scale heat storage technology, it can provide stable high-quality electric energy, overcome the defects of poor power transmission quality caused by the inability to use batteries on a large scale in wind power and photovoltaic power stations, and have a large impact on the grid. It is considered to be one of the most promising power generation methods in renewable energy power generation, and it may become the main energy source in the future. [0003] At present, in the field of trough solar thermal power generation with mature technology, commercial power stations all use heat transfer oil as the heat transfer medium, which leads to high cost o...

Claims

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Application Information

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IPC IPC(8): C09K5/10
Inventor 马重芳吴玉庭任楠
Owner 河北井矿新能源科技有限公司
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