Detailed Explanation of Three Types of CNG Refueling Stations

Standard Station

Process Flow

Natural gas from the urban pipeline network (0.2-0.4 MPa) enters the station, where it is stabilized by a high-precision pressure regulator to ensure stable compressor intake. It then passes through multiple filters to remove large particles, sub-micron impurities, liquid contaminants, and some sulfur compounds. The purified gas is compressed through 3-4 stages in a reciprocating compressor, cooled by a water-based temperature control system. The CNG is then stored in underground storage tanks or above-ground cylinder groups, and a refueling column is used for rapid fueling of taxis, private cars, etc.

Core Equipment

The pressure regulating unit includes intelligent pressure transmitters and electric valves for remote monitoring and precise adjustment. Reciprocating compressors use high-strength alloy pistons and wear-resistant seals for reliable long-term operation. Underground storage tanks are lined with anti-corrosion coatings and reinforced with high-strength steel wire to withstand pressures over 30 MPa, ensuring safe CNG storage. The refueling column integrates high-precision flow meters, IC card readers, and multiple safety features to ensure accurate fueling and operational safety.

Safety Measures

The standard station is equipped with a highly sensitive leak detection system, placing combustible gas detectors in critical areas. If leakage is detected, alarms are triggered, and gas supply is automatically cut off. Electrical equipment is selected and installed according to explosion-proof standards to prevent electrical sparks from causing explosions. Firefighting equipment and emergency escape routes are planned for efficient emergency response.

Suitable Scenarios

Standard stations rely on the urban pipeline network and are quick to build with relatively low investment. They are densely distributed in global urban areas with high population density and older neighborhoods, providing convenient refueling services for scattered, small vehicles, reducing vehicle idle energy consumption, optimizing urban traffic energy micro-cycles, and improving energy supply efficiency.

Parent Station

Process Flow

The station receives high-pressure gas (2-4 MPa) from long-distance pipelines. Multiple large centrifugal compressors drive the gas through high-speed rotating impellers, converting kinetic energy into pressure. Indirect water cooling, paired with brazed plate heat exchangers, precisely controls the temperature. Part of the produced CNG is stored in large spherical storage tanks, while the remainder is transported to nearby sub stations using high-strength seamless steel tube bundles.

Core Equipment

Centrifugal compressors use high-strength titanium alloy impellers and magnetic bearings to reduce friction and increase efficiency. Spherical storage tanks are equipped with safety valves, liquid level gauges, and anti-corrosion coatings to ensure safety under extreme conditions. Refueling columns are optimized for high flow rates and equipped with automatic shut-off and emergency venting controls to ensure efficient and safe refueling of trailers. Transport trailers are fitted with air suspension and GPS systems for stable and secure transportation, with real-time positioning for precise location tracking.

Safety Measures

As a regional CNG hub, the parent station adheres to stringent safety standards. In addition to regular safety features, the spherical storage tanks have multiple safeguards, such as automatic overpressure relief and precise liquid level monitoring to prevent overfilling. The station is built to international seismic standards, considering geological conditions and using seismic-resistant materials and techniques to maintain facility stability during earthquakes. Rigorous security checks are conducted before trailers depart and return to ensure safe transportation throughout.

Suitable Scenarios

Parent stations leverage local gas sources and large production capacity to serve large vehicle fleets such as buses, sanitation vehicles, and logistics trucks in urban new districts, industrial parks, and transportation hubs. They support large-scale clean energy vehicle operations, driving the construction of sub stations and a regional CNG supply system that promotes the large-scale application of clean energy in the region, contributing to sustainable development.

Sub Station

Process Flow

CNG is unloaded from full-load gas cylinder trailers using a high-precision hydraulic pushing device, which precisely controls the unloading speed and ensures smooth transfer into storage tanks. The gas is heated using electric heaters or hot water heat exchangers to raise the temperature to an optimal range before fueling, preventing vehicle gas cylinders from becoming brittle due to the low temperature of the CNG. The gas is then precisely regulated for vehicle fueling by an intelligent refueling machine, which includes fault diagnosis, remote monitoring, and multiple safety protections.

Core Equipment

The tube bundle containers are made from high-strength seamless steel tubes with specially forged joints and metal-wound sealing gaskets, capable of withstanding high-pressure, repeated refueling. The hydraulic pushing device uses servo control for precise force management. Small reciprocating compressors are made from aluminum alloy and feature low-friction pistons to reduce energy consumption and maintenance needs. The heater is equipped with intelligent temperature control and redundant heating elements to ensure stable gas output temperatures under extreme conditions. The refueling machine integrates IoT and mobile payment technologies to improve service quality and operational efficiency.

Safety Measures

Sub stations are equipped with intelligent gas leak monitoring, automatic alarm systems, and fire suppression systems based on air mist or carbon dioxide. Faults or gas leaks in unloading, storage, or refueling processes are immediately detected by sensors, and the system responds with necessary safeguards. Data transmission between components is encrypted to prevent unauthorized access and tampering, ensuring operational confidentiality and security.

Suitable Scenarios

Sub stations are deployed in areas where local demand is concentrated, such as near large transportation terminals or industrial parks. They provide convenient refueling for buses, taxis, and logistics vehicles, acting as important nodes in a larger CNG distribution network, while providing enhanced accessibility and reliable refueling services.