There are several types of natural gas boosters:
1. Piston type natural gas booster
Working principle: The piston type supercharger compresses natural gas through the reciprocating motion of the piston in the cylinder. When the piston moves downwards, the intake valve opens and natural gas enters the cylinder; When the piston moves upward, the intake valve closes, natural gas is compressed, and then discharged through the exhaust valve. This type of supercharger is like an air pump, which increases the pressure of gas through the mechanical movement of the piston.
characteristic:
The pressure range is wide and can generate high pressure, which is generally suitable for natural gas boosting applications that require medium to high pressure, such as some industrial gas scenarios where the pressure can reach tens of megapascals.
The flow rate is relatively stable, and the output natural gas flow rate can be adjusted to a certain extent based on factors such as piston movement speed and cylinder volume.
The structure is relatively complex, and due to the presence of multiple moving parts such as pistons, cylinders, and valves, regular maintenance is required. For example, worn piston rings may cause gas leaks and need to be replaced in a timely manner.
2. Diaphragm type natural gas booster
Working principle: Use a diaphragm to separate the gas compression chamber from the drive chamber. The driving chamber is usually driven by hydraulic oil or other media. When the pressure in the driving chamber changes, the diaphragm will deform, thereby squeezing the chamber on one side of the natural gas and achieving the pressurization of natural gas. For example, when hydraulic oil enters the drive chamber and pushes the diaphragm towards the natural gas chamber, the natural gas is compressed.
characteristic:
Has good sealing performance. Because natural gas and the driving medium are completely separated by a diaphragm, it can effectively prevent natural gas leakage, making it very suitable for occasions with high sealing requirements, such as natural gas refueling stations.
The pressure output is relatively stable. Due to the elastic deformation characteristics of the diaphragm, the compression process of gas is relatively gentle, and the output pressure fluctuation is small, which helps to ensure the stable operation of subsequent gas equipment.
The flow rate is relatively small and generally suitable for natural gas boosting needs with small to medium flow rates. At the same time, the material and service life of the diaphragm are limited, and faults such as diaphragm rupture may occur under high pressure or high frequency use.
3. Centrifugal natural gas booster
Working principle: The main component of a centrifugal supercharger is the impeller. When the impeller rotates at high speed, natural gas is driven to rotate by the impeller. Under the action of centrifugal force, natural gas is thrown towards the edge of the impeller, thereby achieving acceleration and pressurization of the gas. Just like throwing water with a rotating umbrella, water (natural gas) is thrown to the edge during the rotation process, increasing both speed and pressure.
characteristic:
High flow rate, capable of processing large amounts of natural gas, suitable for long-distance natural gas pipelines and other high flow transportation scenarios, can effectively improve the efficiency of natural gas transportation.
Compact structure, compared to other types of superchargers, centrifugal superchargers have a smaller volume and are easier to install and layout under the same flow and pressure requirements.
The requirement for gas purity is high, as high-speed rotating impellers may be damaged if they encounter impurities, and impurities in the gas can also affect the performance of the turbocharger. In addition, under low flow conditions, its efficiency will decrease.
4. Screw type natural gas booster
Working principle: Composed of a pair of interlocking screws, one of which is a male screw and the other is a female screw. When the screw rotates, natural gas is squeezed and transported between the teeth of the screw, gradually compressed from the inlet end to the outlet end. It can be imagined as two interlocking spiral shaped objects, squeezing natural gas from one end to the other like squeezing toothpaste during rotation, and achieving pressurization.
characteristic:
Continuous and stable flow output, due to the continuous rotation of the screw, the pressurization and transportation process of natural gas is continuous, without pulsation like piston type, which can provide stable natural gas flow for gas equipment.
High reliability, screw type supercharger has relatively few moving parts, and the meshing accuracy between screws is high. As long as good lubrication and normal operating conditions are ensured, the service life is long.
It can achieve a high compression ratio and is suitable for natural gas pressurization in various pressure ranges. However, its manufacturing process is complex, the cost is high, and it is sensitive to liquid and solid impurities in the gas.
Comparison of several natural gas boosters:
working principle
Piston type natural gas booster: It changes the volume of gas through the reciprocating motion of the piston in the cylinder, thereby achieving boosting. Just like a pump, the piston sucks in when it moves downwards and compresses and exhausts when it moves upwards
Diaphragm type natural gas booster: using a diaphragm to separate the gas compression chamber from the driving chamber, the pressure change in the driving chamber causes the diaphragm to deform, thereby squeezing the natural gas chamber to achieve boosting
Centrifugal natural gas booster: relying on the high-speed rotating impeller to do work on the gas, the gas is accelerated and thrown towards the edge of the impeller under centrifugal force, and then converted into pressure energy through the diffuser to achieve the purpose of boosting
Screw type natural gas booster: composed of a pair of interlocking screws, when the screws rotate, natural gas is squeezed and transported between the teeth of the screws, gradually compressed from the inlet end to the outlet end
Structural characteristics
Piston type: The structure is relatively complex, including multiple moving parts such as pistons, cylinders, connecting rods, crankshafts, valves, etc. It has a large volume and heavy weight
Diaphragm type: The structure is relatively simple, mainly composed of diaphragm, compression chamber, drive chamber and other components. It has a small volume, light weight, and is easy to install and maintain.
Centrifugal: Compact in structure, mainly composed of impeller, diffuser, volute, shaft, and bearings, with small volume, light weight, and small footprint
Screw type: The structure is also relatively compact, consisting of a screw rotor, slide valve, bearing, oil separator, synchronous gear, etc. The volume and weight are between piston type and centrifugal type
Performance characteristics
Pressure range:
Piston type: It can generate high pressure and is suitable for medium to high pressure applications. The single-stage pressure ratio can reach 10 or more, and multi-stage compression can achieve higher pressure
Diaphragm type: With a relatively narrow pressure range, it is generally suitable for medium and low pressure applications, with a maximum pressure typically below tens of megapascals.
Centrifugal: The pressure ratio usually does not exceed 5, and the boosting capacity is not as good as piston type, but higher pressure can be obtained through multi-stage series connection
Screw type: The exhaust pressure can reach about 2.5MPa, suitable for medium and high pressure working conditions
Traffic characteristics:
Piston type: relatively low flow rate, suitable for gas pressurization with small to medium flow rates, and the flow output has a certain degree of pulsation
Diaphragm type: The flow rate is also small, but its flow output is relatively stable
Centrifugal: High flow rate, suitable for natural gas transportation and pressurization with large flow rates, and wide flow adjustment range, adjustable between 10% and 105%
Screw type: The flow rate is relatively stable and suitable for medium flow situations. When combined with variable frequency speed regulation, it can achieve a wide range of stepless energy adjustment
Efficiency:
Piston type: It has high efficiency under high-pressure and low flow conditions, but due to the presence of many vulnerable parts, the volumetric efficiency will gradually decrease with increasing use time
Diaphragm type: relatively low efficiency, but still has advantages in some specific situations due to its good sealing and stability.
Centrifugal: High mechanical efficiency, high efficiency under high flow and medium high pressure conditions, but prone to surge and efficiency decline under low flow or low load conditions
Screw type: The efficiency is between piston type and centrifugal type, with high rotational speed, large refrigeration capacity, and low requirements for suction superheat. The system has good compatibility
Reliability and maintainability:
Piston type: The reliability is average, but due to the large number of moving parts, vulnerable parts such as piston rings and air valves need to be replaced regularly, resulting in high maintenance costs and significant vibration and noise during operation
Diaphragm type: High reliability, relatively long service life of the diaphragm, and no complex moving parts, low maintenance cost. However, once the diaphragm ruptures, it needs to be replaced in a timely manner
Centrifugal: high reliability, few moving parts, oil-free lubrication, clean exhaust, low maintenance cost, but requires high purity of gas and extremely high speed, demanding strict requirements for bearings, balance, etc
Screw type: High reliability, smooth operation, low vibration, low noise, but high processing technology requirements, high manufacturing costs, and screw rotor leakage gaps, inconvenient maintenance, and high cost of replacing parts
Scope of application
Piston type: commonly used in high-pressure and low flow situations, such as air tightness testing, high-pressure reactor inflation, automotive brake system testing, etc
Diaphragm type: Suitable for occasions with high sealing requirements and small to medium flow rates, such as natural gas refueling stations, laboratory gas pressurization, etc
Centrifugal: widely used in high flow, medium high pressure natural gas transportation and pressurization applications, such as long-distance pipelines in chemical, petroleum, natural gas and other industries, large industrial users, etc
Screw type: suitable for medium flow and medium high pressure applications, such as central air conditioning, industrial refrigeration, refrigeration, heat pump hot water and other fields
