CNG Sub-station Compressor

Qingdao Lenado Intelligent Equipment Co., Ltd. is one of the most reliable manufacturers and suppliers of cng sub-station compressor in China. With a professional production team, we are able to meet the needs of the majority of our customers. Welcome to wholesale bulk customized cng sub-station compressor from our factory.

The CNG substation compressor consists of major units such as the hydraulic system, the gas compression system, the cooling system, the control system, the safety system, and the rain and noise reduction system, which are integrated as a whole in one box through valves and piping. The compressor is designed with a hydraulic reciprocating double force structure and is equipped with a piston position sensing system. The motor drives the hydraulic oil pump to supply oil, and through the integrated reversing system, the hydraulic oil continuously pushes the piston to reciprocate to compress natural gas. The compressor is in a two-stage compression form, and the unit is cooled by water circulation air cooling. The compressor is fully automatically controlled by a PLC control cabinet, which has the advantages of high degree of automation, simple operation, safe and reliable operation, and convenient maintenance. The unit is skid-mounted as a whole and operates in a fully unattended mode.

The hydraulic system consists of the oil tank, suction filter, oil pump motor set, reversing valve group, hydraulic cylinder, oil buffer tank, oil cooler, return oil filter and hydraulic piping, etc. The main motor is connected to the oil pump through an elastic coupling. When the motor is running, it drives the oil pump to operate, increasing the pressure of the hydraulic oil to provide power for the operation of the compression cylinder; The flow of the hydraulic oil is controlled by the reversing control system, and it enters one side of the hydraulic cylinder in sequence to push the piston to move and compress the gas. The hydraulic oil on the other side of the cylinder passes through the reversing control system into the hydraulic oil radiator for cooling, and the cooled hydraulic oil returns to the tank through the return oil filter, completing one cycle of the hydraulic oil circuit.

The gas compression system is composed of high-pressure gas filters, pneumatic ball valves, gas check valves, gas compression cylinders, gas heat exchangers and gas pipelines, etc. The treated pipe network gas is filtered through high-pressure precision gas filters and then enters the gas compression cylinder, which increases the pressure of the gas through two-stage compression. The high-pressure gas, after being cooled in the gas cooler, enters the outlet gas 甁 group or the gas refueling machine.

The compression cylinder in the gas compression system is designed with a hydraulic reciprocating double-force structure. The cylinder body is a three-stage cylinder with two-stage compression and is equipped with a piston position sensing system. The motor drives the hydraulic oil pump to supply oil, and the reversing is carried out through the reversing integrated system to push the piston to reciprocate and compress natural gas.

The CNG substation system uses a water circulation air cooling system with integrated heat sinks, and the entire cooling system consists of three separate heat dissipation systems. They are the natural gas cooling system, the hydraulic oil cooling system and the compression cylinder cooling system.

In the natural gas cooling system, finned high-pressure stainless steel tube radiators are used, and the compressed natural gas at each stage is adequately cooled after passing through the radiators. The hydraulic oil cooling system involves buffering the high-temperature hydraulic oil in the compression cylinder into the oil radiator for cooling, and the cooled hydraulic oil returns to the tank. The refrigerant in the compression cylinder cooling system is antifreeze. After the antifreeze is cooled through the radiator, it can fully dissipate heat for the compression cylinder, thereby effectively protecting the compression cylinder and the sealing elements in the cylinder block.

The main function of the control system is to continuously monitor and control the operating status and parameters of the CNG substation system, and to record and generate alarm information, so that the entire CNG substation system is in a state of monitorable, safe, reliable and stable operation. The control system has an automatic alarm and an automatic emergency accident handling process, which can effectively monitor the status and operating parameters of the substation compressor; The production operation process is automated, and data storage and historical data traceability can be achieved.

The control system, with the programmable logic controller (PLC) as its core equipment, is mainly responsible for the management, scheduling, centralized operation, monitoring system function, automatic logic control, emergency state control, data alarm, online modification and setting of control parameters of the compressors in the CNG substation; It also has the function of recording and generating fault alarm reports, and the real-time status of the CNG substation system can be directly monitored through the human-machine interface.

Two-cylinder compressor control panel screen

The CNG unloading post is a highly intelligent, integrated electromechanical unit designed to unload compressed natural gas from transport trailers to refueling stations or industrial gas pipelines. CNG transported by trailer is connected to the unloading post via quick-connect couplings and high-pressure hoses; the gas flows sequentially through a breakaway valve, unloading ball valve, mass flow meter, check valve, and inlet ball valve before entering the station's compressor. The mass flow meter measures physical parameters-such as gas density and mass-and a signal converter transforms these into electrical pulse signals transmitted to the computer controller. The computer automatically calculates the corresponding mass and cost, displaying the data to the user and thereby completing the unloading measurement process.

                                                                Key Technical Parameters of the CNG Unloading Post

The CNG dispenser is a refueling unit designed for commercial metering at CNG stations. Its computerized control system utilizes a high-performance industrial microprocessor, ensuring exceptional stability even in harsh operating environments. A high-precision mass flow meter serves as the core metering component; it features an integrated temperature sensor for temperature compensation, enabling accurate measurement. The electrical system employs an explosion-proof design to suit the potentially explosive atmosphere of the refueling station, ensuring safe and reliable operation.

                                                                                             CNG Dispenser Specifications

The integrated compressor unit of the CNG daughter station incorporates a gas storage assembly consisting of twenty-five 150L cylinders, with a total water capacity of 3.75 m³.

                                                                   CNG Gas Storage Assembly Specifications

The CNG substation compressor skid is equipped with pressure sensors, combustible gas detectors, and safety valves for oil level, oil temperature, etc. All electrical systems inside the compressor are designed to be explosion-proof, ensuring safe and reliable operation. During the operation of the equipment, if the system detects abnormal protection pressure, oil level or oil temperature, it will promptly sound and light alarm and automatically shut down. When the gas concentration reaches 15% (%LEL) of the lower explosive limit of natural gas, the exhaust fan starts; When the gas concentration reaches 25% (%LEL) of the lower explosive limit, the equipment will sound and light an alarm and shut down automatically.

The box of the CNG substation compressor has the functions of sound insulation, noise reduction and rain protection. The inner layer of the box is made of two layers of sound insulation and sound absorption materials, which can absorb high-frequency noise and block the transmission of low-frequency noise. The equipment box is designed in a modular way for easy maintenance and disassembly. The roof of the box is an integrated roof, completely eliminating the possibility of leakage.

CNG substation process flow

Compressed natural gas is transported to the refueling sub-station by the sub-station transfer trailer and filled to the gas vehicle through the unloading column, skid-mounted CNG sub-station compressor, storage cylinder group, gas vending machine, etc.

Three-line refueling process: First, the natural gas in the tank truck cylinders passes through the low-pressure tube bundle into the refueling machine for refueling; When the pressure in the tanker is lower than the pressure to be filled in the vehicle, start the high-pressure gas in the medium-pressure cylinder group through the medium-pressure tube bundle into the gas dispenser for refueling; When the pressure in the medium pressure tube bundle is lower than the pressure to be filled in the vehicle, the high-pressure gas in the high-pressure cylinder group passes through the high-pressure tube bundle into the gas dispenser for refueling; When the pressure of the high-pressure cylinder group is below 20MPa (adjustable), the compressor automatically starts to inflate the high-pressure cylinder group. See the detailed process flow below:

The design plan of our company is to use the natural gas trailer as the low-pressure cylinder group, part of the gas storage cylinder group as the medium-pressure cylinder group and part as the high-pressure cylinder group, and realize the refueling of the vehicle through the PLC control system. The gas in the gas trailer is directly filled into the car cylinders without the need for the compressor to fill the gas cylinder group and then the gas cylinder group to fill the car cylinders, effectively utilizing the energy of the high-pressure gas in the gas trailer, reducing the start-up frequency of the compressor and saving electricity consumption.

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