Molten salt heat exchange New energy

1. System composition and key components

1.1. Molten salt selection

1.1.1. Nitrate (such as "solar salt": 60% NaNO₃ + 40% KNO₃), applicable temperature range 220°C–565°C, commonly used in solar thermal power generation.

1.1.2. Chloride/fluoride salt (such as NaCl-KCl-ZnCl₂), higher temperature resistance (>800°C), suitable for nuclear energy or ultra-high temperature industry.

1.1.3. Characteristics: low vapor pressure, high heat capacity (~1.5 kJ/kg·K), chemical stability at high temperature.

1.2. Heat exchanger

1.2.1. Function: Efficiently transfer heat between molten salt and working fluid (such as water/steam, air, thermal oil).

1.2.2. Type:

Shell and tube heat exchanger (resistant to high pressure and high temperature)

Plate heat exchanger (compact and efficient, but with low temperature resistance)

1.2.3. Material: corrosion-resistant (such as 316 stainless steel, nickel-based alloy).

1.3. Tank system

1.3.1. High-temperature tank: store molten salt after heat absorption (such as 565°C molten salt in solar thermal power plants).

1.3.2. Low-temperature tank: store molten salt after heat release (usually ~290°C).

1.3.3. Insulation design: ceramic fiber or multi-layer insulation material is used to reduce heat loss.

1.4. Circulation pumping system

1.4.1. High-temperature molten salt pump: corrosion-resistant (such as high-nickel alloy material), and the risk of molten salt solidification needs to be addressed.

1.4.2. Pipeline: Electric heating or insulation design to prevent molten salt from solidifying and clogging.

1.5. Control system

1.5.1. Monitoring parameters: temperature, flow, pressure, liquid level.

1.5.2. Anti-condensation protection: Electric heating or auxiliary heat source to maintain low-temperature pipeline temperature.

1.5.3. Automatic regulation: Control molten salt flow and heat exchange rate according to load demand.

 

2. Application areas

2.1. Concentrated solar power generation (CSP)

Molten salt absorbs heat from solar collectors, stores it in high-temperature tanks, and releases steam on demand to generate electricity (such as China's Qinghai tower concentrated solar power station).

2.2. Industrial waste heat recovery

Recover high-temperature waste heat from industries such as steel and glass for power generation or process heating.

2.3. Nuclear energy system

Fourth-generation nuclear reactors (such as molten salt reactors) directly use molten salt as a coolant and fuel carrier.

2.4. Chemical and metallurgical

High-temperature reactor heating, metal smelting, etc.

3. Advantages and Challenges

3.1. Advantages

3.1.1. High temperature adaptability: The operating temperature is far higher than that of traditional thermal oil (up to 800°C+).

3.1.2. Large-capacity heat storage: Energy storage for more than 10 hours can be achieved (solar thermal power station).

3.1.3. Environmental protection and safety: Molten salt is non-toxic and non-flammable, which is safer than organic heat transfer fluids.

3.2. Challenges

3.2.1. Corrosiveness: Corrosion of metal materials under long-term high temperature requires special treatment.

3.2.2. Antifreeze requirements: Molten salt has a high freezing point (such as solar salt ~220°C), and requires continuous insulation or heating.

3.2.3. Cost: High-temperature materials (such as nickel-based alloys) and system design costs are high.

 

4. Typical cases

4.1. Gemasolar Power Station in Spain: The world's first commercial molten salt tower solar thermal power station, with a heat storage of 15 hours.

4.2. China Dunhuang 100MW Molten Salt Tower Power Station: Annual power generation reaches 390 million kWh, and heat storage time is 12 hours.

5. Molten salt heat exchange system is a key technology for high-temperature energy storage and transmission, and has great potential in renewable energy integration and industrial energy conservation in the future!

Shandong Beichen Mechanical and Electrical Equipment Co., Ltd. has experience in cooperative construction of molten salt heat exchange systems and is one of the few domestic manufacturers that can produce molten salt heat exchange systems. China Dunhuang 100MW Molten Salt Tower Power Station is a project of Shandong Beichen Mechanical and Electrical Equipment Co., Ltd. and Shouhang Hi-Tech Energy Co., Ltd. The project was connected to the grid on December 27, 2018, becoming one of the world's largest concentrated scale, highest heat absorption tower, and strongest heat storage capacity molten salt tower solar thermal power stations. At present, Beichen is also actively cooperating with other companies to develop new molten salt heat exchange solar thermal power stations.

 

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