Temperature and pressure reduction function of steam pipelines

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When steam is discharged from the boiler at high pressure and then sent to various steam-using points, pressure reduction control is generally applied. Why is it necessary to reduce the pressure of steam? The main reasons are as follows: 1. Boilers typically produce high-pressure steam, which allows for smaller boiler sizes, reduces the formation of wet steam, increases the dryness of the steam, and enables its transmission over long distances. 2. It is caused by changes in the density of steam: at high pressures, the density of steam is higher. Therefore, the same-sized pipelines can transport high-pressure steam more effectively than low-pressure steam. Using high-pressure steam transmission allows for smaller pipeline dimensions, thereby saving costs. 3. Condensation occurs when steam is in use; by reducing the pressure of the steam, the pressure of the condensate water is lowered, which prevents flash vapor from being generated during the discharge of the condensate water and thus avoids losses. The energy loss associated with discharging condensate water at low pressure is minimal. 4. Since the temperature and pressure of saturated steam are related to each other, pressure regulators are installed in both sterilization processes and paper drying machine systems to control pressure, thereby regulating the temperature of the process equipment. 5. Process equipment all have their own design pressures. When the supplied steam pressure exceeds the requirements of the process system, pressure reduction is necessary. In some systems, high-pressure condensate is used to generate low-pressure flash steam, thereby achieving energy savings. When the amount of vapor generated is insufficient, a pressure reducing valve is needed to produce low-pressure steam as a supplement. 6. It can reduce the steam load on the boiler, as steam has a higher heat enthalpy at low pressures. The heat enthalpy is 1839 kJ/kg at 2.5 MPa, and 2014 kJ/kg at 1.0 MPa. Therefore, low-pressure steam is more suitable for equipment use. When it comes to the use of steam pressure relief valves, users are particularly concerned about how to use them effectively and how to meet the actual requirements of the equipment in which they are applied. First, it is necessary to understand the basic categories of steam pressure relief valves and their respective advantages and disadvantages.