The hazards of superheated steam on the operation of lithium bromide chillers

The hazards of superheated steam on the operation of lithium bromide chillers

The lithium bromide absorption unit is driven by steam as the core heat source, and its core working principle is to use the thermal energy of steam to drive the circulation of lithium bromide solution. The heat transfer is achieved through the absorption of the solution and the evaporation of the refrigerant water, thus achieving the refrigeration effect. In this process, the quality of steam directly determines the operating efficiency and stability of the refrigeration machine.

The most direct harm of superheated steam is a significant decrease in the heat exchange efficiency of the unit. The core reason is that the heat exchange area design of the high pressure generator of the lithium bromide unit is based on the condensation heat release of saturated steam (saturated steam releases a large amount of latent heat through phase change). After the superheated steam enters the generator, it needs to go through a three-step process of "cooling saturation condensation". The sensible heat released in the first two steps is much smaller than the latent heat, resulting in a decrease in the heat transfer efficiency of the generator.

The main reason is the imbalance between solution concentration and temperature. The crystallization point of lithium bromide solution is determined by both the concentration and temperature of the solution. The large amount of sensible heat released in the early stage of superheated steam will cause excessive evaporation of water in the solution inside the high-pressure generator, resulting in a sharp increase in solution concentration; At the same time, the excessively concentrated solution is prone to crystallization when exchanging heat with the low-temperature dilute solution in the heat exchanger.

The main reason is that overheated steam causes local temperatures to be too high, causing the corrosion inhibitor to decompose and lose its corrosion inhibition effect. At the same time, local high temperatures can damage the protective film formed inside the unit, causing carbon steel or copper heat transfer tubes to come into direct contact with lithium bromide solution, accelerating electrochemical corrosion. Under long-term operation, corrosion products can contaminate the solution and block the heat transfer tubes, seriously affecting the normal operation of the refrigeration unit.

Overheated steam causes excessive boiling and vaporization of the solution inside the generator, resulting in a refrigerant water vapor volume far exceeding the design processing capacity of the condenser, leading to an increase in steam pressure and condensation temperature inside the condenser.

Part of the superheated steam that has not fully exchanged heat with the solution will directly enter the condenser with the refrigerant vapor, adding an additional heat load to the condenser. The condenser cannot transfer this heat to the cooling water in a timely manner, resulting in an increase in the temperature of the refrigerant water, which in turn increases the pressure inside the evaporator, reduces the pressure difference between the absorber and the evaporator, and seriously affects the cooling capacity of the unit.

In response to the above impact, the equipment needs to use saturated steam as the driving energy source for the steam type lithium bromide unit during operation, to prevent problems such as decreased heat transfer efficiency and imbalanced solution concentration and temperature caused by superheated steam. In practical operation, it is recommended to pretreat the superheated steam by installing a temperature and pressure reduction device to regulate its temperature and pressure to the saturated steam parameter range designed by the unit. At the same time, strengthen the insulation measures of the steam pipeline to reduce the heat loss of steam during transportation and avoid secondary overheating. In addition, it is necessary to establish a sound steam quality monitoring mechanism, regularly detect the temperature, pressure, and superheat of steam, and adjust them in real time based on the operating data of the unit to ensure that the concentration and temperature of lithium bromide solution are always within a safe range, reducing the potential risks caused by superheated steam from the source and ensuring the long-term stable and efficient operation of the unit.

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Lithium bromide solution manufacturer

Flier Refrigeration Engineering Technology Co., Ltd is a professional technical service enterprise integrating central air-conditioning host sales, spare parts sales, unit repair and maintenance.

Factory located in Zhenjiang, Jiangsu, covering an area of 25,000 square meters ,and has been built with 1 R&D center, 1 pilot plant, 3 An innovative production, learning, and research base composed of a professional production workshop and its corresponding infrastructure. At present, the company has become a well-known technical service provider in the field of central air conditioning in China.

The company's main business scope includes: central air-conditioning maintenance, cleaning and technical services; cooling tower and fan coil cleaning and maintenance services; custom processing of lithium bromide solution; sales of lithium bromide solution special impurity separators; central air-conditioning host and various zero Sales of accessories; installation and sales of central air conditioning systems, etc.

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