Pressure Reducing Station
Suburban pressure reduction stations
CGS stations are the stations that are installed at the entrance of the cities in order to reduce the gas pressure of the main and secondary transmission lines from high pressure to medium pressure.
Inner city pressure reduction stations
TBS stations are stations that are installed on the outskirts and inside the cities in order to reduce the gas pressure of the supply lines.
Combined pressure reduction station
A combined station is a combination of CGS and TBS stations. Combined stations are used in stations and areas far from the city where using two CGS and TBS stations is not economical.
Industrial pressure reduction station
Major supply of gas to special commercial consumers inside the cities through network lines and with RS pressure reduction installation It takes place on site. The input pressure to the RS stations is 60 psig and the distribution will be based on the amount of consumption and the pressure required for the consumers.
Pressure reduction stations
DRS stations branch off from the urban feeding ring and are basically a type of TBS stations that are different in design. These stations are usually installed for specific areas.
Gas pressure reduction station components
Filtration system
Filters perform the act of separating gas impurities before entering the system and are categorized into the following three types:
Rotary filters
Filters with separator
Filters with separator
regulator
The regulator is a device that can control the gas pressure at a certain level when the gas flow changes.
One of the most important parameters in choosing a regulator is its capacity, which is directly related to the inlet and outlet pressure, gas density, and body shape.
Shut-off safety valve
When there is a malfunction in the regulators of the gas pressure reduction system, there is a possibility of an increase in gas pressure.
In order to reduce this unwanted pressure increase and prevent other parts from being damaged, a part of the regulator’s output gas must be discharged into the space through a reliable valve.
Turbine meters
Turbine meters are the most common meters of the gas pressure reduction station and measure the gas volume from the gas velocity and the amount of movement they transfer to the blades of a turbine.
The range of volume and measurement in these types of meters is very large.
The construction of these meters is such that the speed of the gas entering the meter chamber increases by 2 to 3 times due to the narrowing of its passage, and it has the highest speed when it collides with the turbine blades.
Fragrance system
Equipment such as deodorizers should be used to deodorize the gas at the pressure reduction station.
In pipelines, the gas is odorless; But for correct diagnosis and use, it must be perfumed by a substance called mercaptan.
Heaters
The heating caused by combustion can be transferred directly from the combustion gases to the high-pressure gas or transferred by another fluid (such as water).
In safe conditions, gas heaters, by means of atmospheric burners, heat the distilled water in the chamber and the gas is heated by passing through the indirect gas baths (spiral tubes are embedded in the chamber
The capacity of the gas pressure reduction station
The capacity of the gas pressure reduction station depends on the population of the city and reaches up to 1,000,000 cubic meters per hour.
These stations form an important part of the city’s gas supply system, and their investigation is very important and relevant in order to build new equipment, reduce energy consumption, and reduce pollution.
Methods of increasing the efficiency of the gas pressure reduction station
To check the efficiency of the pressure reduction unit Gas and its increase, it should be checked in which parts or processes there is irreversibility and energy loss. It can be seen that the process that occurs in the regulator is a completely irreversible suffocation process; Therefore, one of the ways to increase efficiency is to modify this step.
One way to improve is to use an expansion turbine and a combination of an expansion turbine and a fuel cell.
Also, due to the improper design of natural gas pressure reduction station heaters, their efficiency is usually much lower than the ideal value.
For this reason, a significant amount of thermal energy of the fuel is wasted through exhaust gases from the chimney. So that the smoke coming out of the heater chimney has a high temperature of about 400 degrees Celsius and enters the air. Therefore, another method of increasing the efficiency of recycling the heat energy of exhaust gases from the chimney is.
