What Is the Classification of CNG filling stations?
There are three main types of CNG fueling stations: Mother Stations, Daughter Stations, and Standard Stations. Each type of station plays a critical role in the infrastructure of compressed natural gas (CNG) distribution, offering unique advantages depending on location and availability of gas pipelines.
Mother Station:
A Mother Station is a large-scale CNG fueling station responsible for filling compressed natural gas into onboard gas cylinders. This station typically sources gas from high-pressure pipelines, with inlet pressures ranging from 1 to 1.5 MPa. The gas undergoes processing, including desulfurization and dehydration, before being compressed by large compressors. The compressed gas is stored in high-pressure gas cylinders (25 MPa) and transported by CNG tank trailers to Daughter Stations. Mother Stations are often located near city gate stations and serve dual purposes: refueling vehicles and acting as supply hubs for daughter stations. Their refueling capacity ranges from 2,500 to 4,000 Nm³/h.
Daughter Station:
A Daughter Station relies on compressed gas delivered by CNG tank trailers from the Mother Station. These stations are located in areas where natural gas pipelines are not available, such as urban centers or industrial zones in rural towns. The purpose of a Daughter Station is to facilitate vehicle refueling by offloading the compressed natural gas into vehicle gas cylinders. Since no direct gas pipelines are available at these locations, CNG is transported via trailers at high pressures (25 MPa) from the Mother Station to the Daughter Station. This type of station ensures the availability of CNG in areas where natural gas pipelines are absent, thus promoting the use of natural gas as an energy source for vehicles.
Standard Station:
A Standard Station, also known as a Conventional Station, receives natural gas directly from medium-pressure pipelines at an inlet pressure of approximately 0.4 MPa. The gas is processed (desulfurized and dehydrated) and then compressed to 25 MPa. The compressed gas is either dispensed directly into vehicles or stored in fixed gas cylinder groups (or wells) for later use. Standard stations are typically located in areas where natural gas pipelines are accessible, such as cities or industrial hubs with existing pipeline infrastructure. The refueling capacity of a standard station usually ranges from 600 to 1,000 Nm³/h.
In conclusion, CNG stations are crucial components of the natural gas vehicle infrastructure, with Mother, Daughter, and Standard Stations working together to provide widespread access to compressed natural gas. These stations are designed to meet the demands of different locations and gas pipeline availability, ensuring that CNG remains a viable and environmentally friendly alternative to traditional fuels.
