CNG Pressure Reducing Skid

Basic components of CNG pressure reducing skid

1. Unloading part: used to connect the pressure reducing skid and the tank car air source. It plays the role of unloading CNG trucks and has a pressure relief function at the end. You can choose an independent degassing device or a built-in degassing part integrated with the pressure reducing skid.

2. Gas heating: Since CNG produces a high temperature drop due to high pressure drop after decompression, It will cause low temperature effects on downstream equipment, so temperature compensation of the gas is required. Gas heating methods include: water bath electric heating, hot water circulation heat exchange, etc. Single-stage heating or multi-stage heating can be selected according to the working conditions.

3. Pressure reduction part: According to the outbound air supply demand, Choose two-stage pressure reduction or three-stage pressure reduction process. In addition to the pressure regulator, the pressure reducing part is also equipped with safety protection equipment.

4. Metering part: After installing the metering equipment at the low-pressure end of the CNG pressure reducing skid, The metering function of the gas unloading column is desirable because the CNG skid has a gas heating function, which can ensure the outbound gas is at normal temperature, and choosing back-end measurement ensures measurement accuracy.

5. Odorizing part: for urban medium-pressure pipe network gas replenishment or residential gas supply, The gas must be odorized. Pump type odorizing or differential pressure odorizing device can be selected.

6. Control system: on-site control scheme, automatic temperature adjustment control, Automatic control of pressure over-limit pneumatic valve, odor control, etc.

Basic process of CNG pressure reduction skid

1. Connect the degassing part of the pressure reducing skid to the high-pressure bottle group of the tanker through a high-pressure hose. The compressed natural gas passes through the valve and the high-pressure shut-off valve and then enters the heat exchanger, where the gas is heated.

2. Reduce the pressure to below 4.0MPa through the first-stage pressure regulator (the first-stage pressure regulator can be set as needed), Then the second-stage pressure regulator reduces the pressure to the pressure required for outbound station (when the outbound pressure is low, It is necessary to add a third-stage medium and low pressure regulator). If the heat exchanger is a two-stage heat exchange design, Then the gas will undergo a second heat exchange before the second stage pressure regulation.

3. Enter the flow meter for measurement, and finally odorize the gas. Supply gas to medium pressure pipeline network or downstream users.

4. The control system will control the heat exchanger based on temperature feedback. Realize automatic control of on-site temperature; at the same time, the control system monitors the pressure signal, When the pressure exceeds the safety set value, the pneumatic emergency valve will be automatically controlled to cut off. In order to protect the safety of equipment, in addition to basic processes, New designs can be made according to user needs, such as using two-stage heat exchange and three-stage pressure reduction, etc.

Features

It adopts two-stage or three-stage pressure regulating process and has the functions of purification, metering, pressure regulation, Distribution and other functions; The large heating device can choose electric heating or water/steam heating according to needs; Compact structure, complete functions, reliable performance; * Expandable function detection function, station control system, odorizing and wearing remote Control, leak alarm.

The main technical parameters

Inlet pressure range P1 s25MPa

Outlet pressure range P2 0.05-4.0MPa

The voltage stabilization accuracy level can reach AC5

The closing pressure level can reach SG5

-20-70°C ambient temperature