When steam is generated in a boiler and transported to various equipment points, pressure control is typically necessary.
There are several reasons why steam needs to be reduced in pressure:
Boilers typically produce high-pressure steam, which reduces the size of the boiler, decreases the likelihood of wet steam, increases steam dryness, and facilitates long-distance transport.
Changes in steam density cause the need for high-pressure steam to be transported through smaller pipelines than low-pressure steam. Using high-pressure steam for transport saves on costs.
Steam use may result in condensation, and reducing steam pressure reduces the pressure of condensate water, prevents flashing of steam when condensate water is released, and reduces energy losses.
In sterilization processes and paper drying machines, pressure control valves are installed to regulate pressure and control equipment temperatures because saturated steam temperature and pressure are correlated.
Process equipment is designed to withstand certain pressures, and when the supplied steam pressure exceeds the pressure required by the system, pressure reduction is necessary. Some systems use high-pressure condensate water to produce low-pressure flash steam for energy savings, and when there is insufficient flash steam, low-pressure steam must be produced using pressure reducing valves.
Reducing steam pressure can reduce boiler steam load because low-pressure steam has a higher enthalpy than high-pressure steam. The enthalpy of 2.5 MPa steam is 1839 kJ/kg, while that of 1.0 MPa steam is 2014 kJ/kg. Therefore, low-pressure steam is more suitable for equipment use.
Regarding the use of steam pressure reducing valves, users are particularly concerned about how to use them properly and meet the actual needs of their application equipment. First, it is necessary to understand the basic types of steam pressure reducing valves and their respective advantages and disadvantages.