Mixed carbonate heat transfer and heat storage working medium

Abstract

A mixed carbonate heat transfer and heat storage working medium comprises the following molten salt components by mole fraction: 20%-40% of K2CO3, 23%-42% of Li2CO3, 30%-60% of Na2CO3, and 5.5-15% of CaCO3. The molten salt working medium has the advantages of high heat transfer coefficient, high working temperature, less corrosion, low vapor pressure, environmental-friendliness, good safety and the like.

Description

technical field [0001] The invention relates to a heat transfer and heat storage working medium, in particular to a heat transfer and heat storage working medium used in a solar thermal power generation system, and belongs to the technical field of energy materials. Background technique [0002] Concentrating solar thermal power generation is a large-scale, commercially viable power generation model. It has a heat storage system, can provide continuous and uninterrupted power supply, and has good power quality, so it is more competitive than wind power and solar photovoltaic power generation. Heat transfer and heat storage technology is one of the key technologies, and it is very important to choose a heat transfer and heat storage medium with good thermal performance and low price. Commonly used heat storage media include sand-stone-mineral oil, concrete, heat transfer oil, liquid metal and molten salt. The sand-stone-mineral oil system has a complex structure and low eff...

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Problems solved by technology

The sand-stone-mineral oil system has a complex structure and low efficiency; concrete is used as a heat storage medium, and its internal heat exchange tubes have high requirements, accounting for 45-50% of the cost of the entire heat storage system; heat transfer oil can be used for both heat storage and To transfer heat, it is generally used in occasions below 400°C, but its vapor pressure at high temperature is very high (greater than 1MPa at 400°C), and using it as a heat storage medium requires special pressure valves and other equipment, and there are also large problems. Difficult, easy to cause fire, and expensive; liquid metal can be applied to higher temperatures, and the metal material has high density, high thermal conductivity, uniform overall temperature distribution, and good heat absorption and heat release performance, but the specific heat capacity of metal Small, the temperature fluctuates greatly when the heat load is high, and it is flammable and explosive in contact with air at high temperature, which is very dangerous

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