Description CNG refuel stations

PULITA New Energys CNG refuel stations offer a complete suite of solutions tailored to both fixed and mobile installations. Each station includes essential components such as high-quality gas cylinder groups, robust compressors, efficient dispensers, advanced gas unloading columns, precise metering systems, effective gas filters, and reliable gas leak alarm systems.
Designed to handle capacities ranging from 1000 to 3000 standard cubic meters, our refuel stations are equipped with state-of-the-art 250bar high-efficiency compressors and dispensers.
This setup ensures optimal performance and swift refueling of small vehicles.

The integrated compressor of the CNG substation consists of a discharge column, gas filter, compressor, oil-gas cooling system, gas storage bottles, and gas dispenser, all of which are integrated into a rainproof and noise-reducing enclosure through valves and piping. The compressor features a hydraulic reciprocating double-acting structure design and is equipped with a piston position sensing system. A motor drives a hydraulic oil pump to supply oil, and an integrated reversing system continuously pushes the hydraulic oil to drive the piston in a reciprocating motion to compress natural gas.

The compressor employs a two-stage compression method, and the unit is cooled using a water circulation air cooling system.The compressor is controlled by a PLC control cabinet, enabling fully automated operation with high levels of automation, simple operation, safe and reliable performance, and convenient maintenance. The entire unit is skid-mounted and operates in a completely unmanned mode.

The control systems main function is to continuously monitor and control the operating status and parameters of the CNG substation system, recording and generating alarm information to ensure the entire CNG substation system remains in a controllable, safe, reliable, and stable operational state. The system features automatic alarms and emergency handling procedures, effectively monitoring the state and operational parameters of the gas compressor. The production processes are automated, allowing for data storage and historical data tracing.

The control system is centered around a Programmable Logic Controller (PLC), which manages the substation compressors operations, scheduling, centralized control, monitoring functions, automated logic control, emergency state control, data alarms, and online modification of control parameters. It also generates fault alarm reports, and through a human-machine interface, real-time monitoring of the CNG substation systems status is available.

The CNG dispenser is the equipment used for trade settlement at refueling stations. Its computer control section employs high-performance industrial microprocessor chips, maintaining high stability even in harsh working environments. A high-precision mass flow meter serves as the core metering component, with a built-in temperature sensor for temperature compensation, ensuring accurate measurements. The electrical components are designed with explosion-proof structures to adapt to the explosive environment of the refueling station, ensuring safety and reliability.

This project features a standalone skid for the gas storage cylinder group, which integrates a storage cylinder group consisting of 63 cylinders with a water capacity of 11.97 m³. The 63 cylinders are divided into three sections, each comprising 21 cylinders. The low, medium, and high-pressure storage cylinders are arranged in a ratio of 1:1:1.


Integrated Compressor Composition of CNG Substation
The integrated compressor of the CNG substation consists of a discharge column, gas filter, compressor,
oil-gas cooling system, gas storage bottles, and gas dispenser, all of which are integrated into a rainproof
and noise-reducing enclosure through valves and piping. The compressor features a hydraulic reciprocating
double-acting structure design and is equipped with a piston position sensing system. A motor drives a
hydraulic oil pump to supply oil, and an integrated reversing system continuously pushes the hydraulic oil to
drive the piston in a reciprocating motion to compress natural gas. The compressor employs a two-stage
compression method, and the unit is cooled using a water circulation air cooling system.
The compressor is controlled by a PLC control cabinet, enabling fully automated operation with high levels
of automation, simple operation, safe and reliable performance, and convenient maintenance. The entire
unit is skid-mounted and operates in a completely unmanned mode.


Hydraulic System
The hydraulic system consists of a tank, suction filter, oil pump motor unit, directional control valve group,
hydraulic cylinder, oil buff er tank, oil cooler, return filter, and hydraulic piping. The main motor is connected
to the oil pump via an elastic coupling. When the motor operates, it drives the oil pump, which pressurizes
the hydraulic oil to provide power for the operation of the compression cylinder. The hydraulic oil flows
through a directional control system and enters one side of the hydraulic cylinder, pushing the piston to
compress the gas.
The hydraulic oil on the other side of the cylinder passes through the directional control system into the
hydraulic oil cooler for cooling. The cooled hydraulic oil then returns to the tank via the return filter,
completing a cycle of hydraulic oil circulation.
Due to the control of the hydraulic system, the operation of the motor and the movement of the piston within
the cylinder are effectively isolated. This means that when the motor starts, it does not need to vent the
high-pressure gas in the compression cylinder. This allows for immediate startup, saving energy and
improving the efficiency of the compressor.

Cooling System
The CNG substation system employs a water-circulating air cooling system, consisting of three independent
cooling sub-systems: the natural gas cooling system, hydraulic oil cooling system, and compression
cylinder cooling system.
The natural gas cooling system utilises a finned high-pressure stainless steel tube heat exchanger,
ensuring thorough cooling off the compressed natural gas. The hydraulic oil cooling system channels high temperature hydraulic oil from the compression cylinder through a buffer before entering the oil cooler for cooling; the cooled hydraulic oil then returns to the oil tank In the compression cylinder cooling system, the refrigerant is antifreeze.
After passing through the heat exchanger, the antifreeze effectively cools the compression cylinder, providing optimal protection for both
the compression cylinder and the seals within the cylinder body.

Control System
The control systems main function is to continuously monitor and control the operating status and
parameters of the CNG substation system, recording and generating alarm information to ensure the entire
CNG substation system remains in a controllable, safe, reliable, and stable operational state. The system
features automatic alarms and emergency handling procedures, eff ectively monitoring the state and
operational parameters of the gas compressor. The production processes are automated, allowing for data
storage and historical data tracing.
The control system is centered around a Programmable Logic Controller (PLC), which manages the
substation compressors operations, scheduling, centralized control, monitoring functions, automated logic
control, emergency state control, data alarms, and online modification of control parameters. It also
generates fault alarm reports, and through a human-machine interface, real-time monitoring of the CNG
substation systems status is available.

CNG Refueling System
The CNG dispenser is the equipment used for trade settlement at refueling stations. Its computer control
section employs high-performance industrial microprocessor chips, maintaining high stability even in harsh
working environments. A high-precision mass flow meter serves as the core metering component, with a builtin temperature sensor for temperature compensation, ensuring accurate measurements. The electrical components are designed with explosion-proof structures to adapt to the explosive environment of the
refueling station, ensuring safety and reliability

Safety System
The integrated compressor in the CNG substation features pressure sensors, combustible gas
detectors, and monitoring for oil level, oil temperature, and safety valves. The entire electrical system is
designed to be explosion-proof, ensuring safe and reliable operation. Ifthesystem detects anomaliesin
protection pressure, oil level, or oil temperature during operation, it will issue immediate visual and auditory
alarms and automatically shut down. When the gas concentration reaches 15% of the lower explosive limit
(%LEL), the exhaust fan activates; at 30% (%LEL), the system alarms and automatically shuts down.

CNG Storage System
This project features a standalone skid for the gas storage cylinder group, which integrates a storage cylinder
group consisting of 63 cylinders with a water capacity of
11.97 m³. The 63 cylinders are divided into three sections, each comprising 21 cylinders. The low, medium,
and high-pressure storage cylinders are arranged in a ratio of 1:1:1.