CNG Pressure Reducing Skid

Product Overview

HUAYI CNG Pressure Reducing Skid provides an integrated solution for receiving high-pressure compressed natural gas and supplying gas at the required downstream pressure. The system is typically connected to a CNG tube trailer through a high-pressure unloading connection.

Because significant gas cooling can occur during high-pressure reduction, the system can incorporate gas heating before or between pressure reduction stages. The overall configuration can be engineered according to the CNG supply pressure, required outlet pressure, gas flow rate and downstream gas supply conditions.

Typical System Configuration

A CNG pressure reducing skid can include:

• CNG unloading connection and high-pressure piping

• Gas heating system

• Two-stage or three-stage pressure reduction

• Pressure regulators and safety protection devices

• Gas flow metering

• Isolation and emergency shut-off valves

• Pressure and temperature instrumentation

• Local control system

• Optional gas odorization system

• Interconnecting piping and skid structure

The actual configuration is determined according to project requirements.

CNG Unloading

The unloading section connects the pressure reducing skid with the CNG tube trailer through a suitable high-pressure connection. High-pressure compressed natural gas enters the skid and is directed to the downstream heating and pressure reduction sections.

The unloading arrangement can be configured according to the tube trailer connection, operating pressure and project requirements.

Gas Heating

High-pressure CNG experiences a significant temperature drop during pressure reduction. Gas heating can therefore be incorporated to maintain suitable operating temperatures and protect downstream equipment.

Depending on the operating conditions, heating arrangements may include:

• Electric water bath heating

• Hot-water circulation heating

• Single-stage heating

• Multi-stage heating

The heating method and heat duty should be selected according to the required gas flow and pressure reduction conditions.

Multi-Stage Pressure Reduction

The system can use two-stage or three-stage pressure reduction depending on the inlet and outlet pressure requirements.

High-pressure CNG is reduced progressively through pressure regulators to achieve the required downstream supply pressure. Safety protection devices can be incorporated into the pressure reduction stages according to the system design.

Gas Metering

A gas flow meter can be installed downstream of the pressure reduction and heating sections to measure the gas supplied to the downstream network or user.

The type and configuration of the metering system can be selected according to the required flow range, pressure conditions and project specifications.

Optional Gas Odorization

For applications supplying city gas distribution networks or other systems requiring odorized natural gas, an odorization system can be integrated with the CNG pressure reducing skid.

Automatic pump-type or other suitable odorization configurations can be selected according to project requirements.

Control and Safety

Depending on the project configuration, the control system can monitor operating parameters such as gas pressure and temperature and provide control functions for the heating and pressure reduction process.

Emergency shut-off and overpressure protection functions can also be incorporated according to the required system design and safety philosophy.

Typical Applications

CNG pressure reducing skids can be used for:

• CNG tube trailer gas unloading stations

• Areas without pipeline natural gas supply

• Temporary natural gas supply

• Peak-shaving and supplementary gas supply

• City gas distribution networks

• Industrial natural gas supply

• Emergency gas supply applications

Reference Technical Parameters

The above parameters are based on the existing product information and are provided for reference. Final system configuration and technical parameters should be determined according to the actual project conditions.

Customized Engineering

HUAYI can configure the CNG pressure reducing skid according to project-specific inlet pressure, outlet pressure, gas flow rate, ambient conditions, heating requirements, metering requirements, control philosophy and downstream gas supply conditions.

Customers are recommended to provide the required gas flow, CNG inlet pressure range, required outlet pressure, gas composition, ambient temperature and downstream application for technical evaluation and system configuration.