Why do steam lines need relief valves for decompression?

Steam from the boiler by high pressure output and then transported to the equipment to use the steam point, usually decompression control.Why does steam need to be decompressed?The main reasons are as follows:

1. The boiler usually produces high-pressure steam, which can reduce the size of the boiler, reduce the occurrence of wet steam, improve the dryness of steam, and carry out long-distance transportation.

2. Due to the change in the density of steam, the density of steam is high at high pressure. High-pressure steam can be transported by the same diameter pipe to be larger than low-pressure steam.

3. Condensation will occur when the steam is used, and the steam after decompression will reduce the pressure of condensed water to avoid the loss caused by flash steam when condensed water is discharged, and the energy loss caused by condensed water discharged under low pressure is small.

4. Since the temperature and pressure of saturated steam are corresponding, pressure reducing valves are installed in the surface temperature control of sterilization process and paper dryer to control the pressure, thus controlling the temperature of process equipment.

5, the process equipment has its own design pressure, when the supply of steam pressure more than the needs of the process system, the need to reduce pressure, when some systems are with high pressure condensed water to produce low pressure flash steam, to achieve the purpose of energy saving.When the resulting flash steam is insufficient, it is necessary to generate low-pressure steam through the relief valve to replenish.

6. The steam load of the boiler can be reduced because of the high enthalpy of steam under low pressure.The enthalpy value at 2.5mpa is 1839kJ/kg, and that at 1.0mpa is 2014kJ/kg.Therefore, low pressure steam is more suitable for equipment use.

For the use of steam relief valve, the user is particularly concerned about how to use well, how to meet the actual requirements of the application equipment.First you need to know the basic types of steam relief valves and their advantages and disadvantages.