CNG Decompression Equipment

With the change of China's energy structure and the constant increase of environmental protection, the natural gas develops rapidly in development and utilization. After purifying and compressing the natural gas from the wellhead or pipeline, the CNG is stored and transported at high pressure to the place of use, and decompressed and directly delivered to the pipeline network through multi-stage heat exchange to supply various users.

The range of 300km between the CNG station and the place of use is economic, no more than 500km generally, with a supply scale of 2,000-4,000 households. The air supply of 200-5,000Nm³/h is appropriate. Too large or too small air supply will increase the unit gas costs.

The long-distance pipeline of this system has small investment scale, short construction period and quick payback. It can be served as the peak load and emergency gas sources of the long-distance pipeline in future.

Working principle of CNG station: Preheat the high pressure natural gas in the pry tank, depressurize gradually, and perform working procedures such as safety control, metering and deodorization to make the gas reach the pressure conforming to the specification requirements, then deliver to the pipeline.

The CNG station can be divided into two-staged pressure regulation and three-staged pressure regulation according to the pressure regulation mechanism.

According to the layout in the equipment station and the equipment function, the CNG station includes: Unloading system (high pressure hose, quick coupler and high-pressure valve), pressure regulating heat exchange system (high pressure emergency cutoff valve, heat exchanger, pressure regulator and relief valve), flow metering system (flowmeter), control system (central console) and heating system (gas boiler, hot water pump, etc.).

The natural gas in the pry car enters the pressure regulating heat exchange system via the unloading system for 2 heat exchanges, then enters the flow metering and odorization systems through 2 or 3 pressure regulations, then enters the pipeline network. The heating system provides the heat required for the gas pressure reducing process, and the control system monitors the whole system.

1. A.Secondary pressure regulating technology: First, connect with the skid-mounted steel tanker by using the high-pressure hose and quick coupler. The CNG enters the primary heat exchanger through a ball valve and high-pressure cutoff valve to heat the gas, then is decompressed to 1.0-4.0MPa through the primary pressure regulator, and regulated to 0.1-0.4MPa through the heating of the secondary heat exchanger and the pressure regulation of the secondary pressure regulator, then enters the flowmeter for flow metering, finally odorizes the gas, and is delivered to the medium pressure pipeline network.
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3. All the gas pressures, temperatures, flow rates and water temperatures at different levels in the station, control of the key valves and the switch between 2 paths are interlocking-controlled by the console.
4. B.Third pressure regulating technology: First, connect with the skid-mounted steel tanker by using the high-pressure hose and quick coupler. The CNG enters the primary heat exchanger through a ball valve and high pressure cutoff valve to heat the gas, then is decompressed to 3.0-7.5MPa through the primary pressure regulator, regulated to 1.6-2.5MPa through the heating of the secondary heat exchanger and the pressure regulation of the secondary pressure regulator, and regulated to 0.1-0.4MPa through the third pressure regulator, then enters the flowmeter for flow metering, finally odorizes the gas, and is delivered to the medium pressure pipeline network.
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6. All the gas pressures, swelling capacities, flow rates and water temperatures at different levels in the station, control of the key valves and the switch between 2 paths are interlocking-controlled by the console.
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   CNG Decompression Equipment

   Model	CNG-300	CNG-500	CNG-1000		CNG-2000	CNG-2000	CNG-3000	CNG-4000	CNG-5000
   Hourly Maximum Flow Rate (Nm³/h)	300	500	1000	2000		2000	3000	4000	5000
   Structure Form	One for use and one for backup
   Pressure Regulation Level	Secondary pressure regulation					Third pressure regulation
   Inlet Temperature (°C)	65-85	65-85	65-85		65-85	65-85	65-85	65-85	65-85
   Primary Heat Exchange Return Water Temperature (°C)	60	60	60		60	60	60	60	60
   Secondary Heat Exchange Return Water Temperature (°C)	60	60	60		60	60	60	60	60
   Outlet Gas Temperature (°C)	10-20	10-20	10-20		10-20	10-20	10-20	10-20	10-20
   （Mpa） Primary Post-regulation Gas Pressure (Mpa)	1.0-6.0	1.0-6.0	2.0~ 6.0		2.0-6.0	3.0~ 7.5	3.0-7.5	3.0~ 7.5	3.0-7.5
   Secondary Post-regulation Gas Pressure (Mpa)	0.1 ~0.4	0.1-0.4	0.1-0.4		0.1-0.4	1.6-2.5	1.6-2.5	1.6-2.5	1.6-2.5
   Third Post-regulation Gas Pressure (Mpa)	-	-	-		-	0.1-0.4	0.1-0.4	0.1-0.4	0.1-0.4
   Outlet Gas Pressure (Mpa)	0.1-0.4	0.1-0.4	0.1-0.4		0.1-0.4	0.1-0.4	0.1-0.4	0.1-0.4	0.1-0.4
   Primary Release Pressure (Mpa)	1.3 ~ 7.8	1.3 ~ 7.8	2.6 ~ 7.8		2.6 ~ 7.8	3.9-9.75	3.9- 9.75	3.9-9.75	3.9- 9.75
   Secondary Release Pressure (Mpa)	0.13-0.52	0.13-0.52	0.13-0.52		0.13-0.52	2.08-3.25	2.08-3.25	2.08-3.25	2.08-3.25
   Third Release Pressure (Mpa)	-	-	-		-	0.13 - 0.52	0.13 - 0.52	0.13 - 0.52	0.13 - 0.52
   Inlet Diameter	DN25	DN25	DN25		DN40	DN40	DN50	DN50	DN50
   Outlet Diameter	DN50	DN80	DN100		DN100	DN100	DN150	DN150	DN150
   Dimensions (m)	6.5x2x2.3	6.5x2x2.3	6.5x2x2.3		6.5x2x2.3	6.5x2x2.3	6.5x2x2.3	6.5x2x2.3	6.5x2x2.3
   Weight (t)	2.6	2.7	2.8		3	3.5	4	4.3	4.6
   Optional Boiler Power (Large Calorie)	2.0	2.5	5		10	10	15	20	25