cng compressor

Types of CNG Compressors

A CNG compressor is an equipment used to compress natural gas to a pressure higher than the atmosphere. CNG is fixed compressed at a specific place (like a CNG station) and then distributed through pipelines. There are various types of CNG compressors. The following table summarizes some of them:

• Reciprocating CNG Compressors

  They work like piston pumps whose primary function is to suck a considerable amount of gas and increase its pressure by discharging it back. They are often used in gas transport pipeline systems, gas gathering systems, liquid natural gas (LNG) terminals, gas storage facilities, gas processing plants, and offshore/onshore gas production sites.

• Rotary CNG Compressor

  It uses a rotating mechanism to suck and compress gas at high pressure. Rotary CNG compressors are often used in industrial manufacturing operations, power generation facilities, water and wastewater treatment plants, food and beverage production facilities, petroleum refineries, chemical processing plants, construction site operations, and gas-fired power plants.

• Screw CNG Compressor

  It uses two screws rotating in an opposite direction to compress natural gases. The CNG compressor works perfectly in gas processing industries, petrochemical facilities, power generation, waste treatment (especially in anaerobic digesters), refineries, offshore platforms, manufacturing sites, multigas compression, and automotive industry tests and laboratories.

• Centrifugal CNG Compressor

  It uses a high-speed driver to rotate a disk with impellers on the side. The driver's rotational speed causes the impeller to rotate, thereby compressing and discharging natural gas. Centrifugal CNG compressors are often applied in petrochemical plants, natural gas processing facilities, gas transmission pipelines, LNG production facilities, power generation plants, offshore oil and natural gas platforms, industrial manufacturing plants (particularly in the automotive industry), waste treatment facilities, oil refineries, and chemical reaction systems.

• Diaphragm CNG Compressors

  Diaphragm CNG compressors are known for their robust resistance to corrosion and capability of handling non-lubricated gases. More importantly, they ensure that gas maintains its purity by preventing any gas leakage into the atmosphere. Due to these features, diaphragm CNG compressors are mostly found in the chemical industry, pharmaceutical manufacturing, food and beverage production, wastewater treatment, environmental monitoring, and laboratory and research facilities.

Specification and Maintenance of CNG Compressors

Some key specifications that people should consider when buying a CNG compressor include the flow rate, discharge, and pressure ratio.

• Flow Rate:

  Flow rate, also known as throughput, is the volume or mass of natural gas that the CNG compressor conveys per unit of time. It is usually measured in cubic feet per minute (CFM). Businesses should choose a compressor with a flow rate that matches their gas supply demands, applications, or refueling stations.

• Discharge Pressure:

  The discharge pressure indicates the highest pressure at which the CNG compressor can deliver gas. It is usually measured in pounds per square inch (PSI) or bars. Users should choose a compressor that can achieve the pressure required for their storage tanks, pipelines, or utilization points.

• Pressure Ratio:

  The pressure ratio is the ratio between the intake and discharge pressure of the CNG compressor. It reflects the compression performance of the compressor. A higher pressure ratio means that the compressor can handle higher pressures and possibly greater depths. Users should choose a compressor with a pressure ratio that meets the demands of their gas processing or storage systems.

CNG compressors need regular maintenance for optimal performance. Manufacturers recommend some maintenance tips to keep the compressor in good shape. First, check the intake gas to ensure it is clean. Applying a gas scrubber can help remove contaminants. Second, check for any gas leaks from the fittings or pipe connections. Third, inspect the compressor's drive system. Look at the belts, chains, and couplings to ensure they are not worn out or loose. Belts or chains that are worn out should be replaced to prevent driving failure.

Daily lubrication is essential for CNG compressors. The machine running smoothly and prolonging its life will require frequent lubrication. Users should check the lubrication daily on the gas compression units. If the lubricant is low or dirty, they should top it up or change it. Always follow the manufacturer's lubrication guidance. Also, check the moving parts for any wear and tear so that they can be fixed before they worsen. Consider having a routine maintenance schedule for the CNG compressor to address issues promptly and keep it working smoothly.

CNG compressor usage scenarios

The primary use of the CNG compressor is to increase the amount of natural gas to meet pipeline storage or transportation demands. Such demands typically arise when there is a high market demand for natural gas. However, other usage scenarios for the CNG compressor include the following:

• Gas Wells:

  In gas wells, CNG compressors extract natural gas from the well and transport it through pipelines to processing facilities. The CNG compressor performs this function by increasing the gas's pressure to a level that enables it to flow through pipelines without any hitches.

• Processing Facilities:

  At processing facilities, the CNG compressor is used to pump processed natural gas to consumers or distribution centers. It maintains the gas's pressure so that it can be distributed efficiently to users or stored in facilities.

• Storage Facilities:

  CNG compressors can also be used to manage natural gas in storage facilities. In this case, the compressor adds more pressure to the gas so that it can be stored securely in storage facilities, especially when market demand is low.

• Power Plants:

  CNG compressors are also used at power plants to supply natural gas to turbines that produce electricity. The compressor ensures that there is a constant supply of gas with the ideal pressure required by the turbines.

• Industrial Facilities:

  Some industries use the CNG compressor to obtain natural gas with the necessary pressure to run their production processes. For instance, certain chemical production facilities utilize gas as one of the raw materials in their production lines.

• Transportation of Natural Gas:

  CNG compressors are used in transportation systems (mainly CNG vehicles) that transport natural gas from one location to another. Such systems include trucks equipped with CNG containers that use CNG compressors to load and transport natural gas containers.

How to choose CNG compressors

When choosing a natural gas compressor (CNG compressor), things like capacity, power source, safety features, noise level, and maintenance requirements must be considered.

• Capacity: The compressor's capacity must be aligned with the expected demand. Consider the required volume of gas to be compressed per unit of time. This may be determined by factors like the intended usage, the number of vehicles (if it's for a fueling station) or the scale of the industrial process.
• Power source: CNG compressors are available with different power sources, including electric motors and diesel or natural gas engines. An electric motor may be used if there is access to the electric grid, but a diesel or natural gas engine may be used in remote locations.
• Safety features: Safety is paramount when handling natural gas. Choose a compressor with the right safety features, like explosion-proof designs, leak detection systems, and automatic shutdown mechanisms. Comply with local safety regulations and standards.
• Noise Level: CNG compressors can be noisy. Consider the environmental impact and choose a CNG compressor with a motor that has noise-reducing features, like soundproof enclosures or silencer exhaust systems, to reduce transmission loss. This can help minimize noise pollution in the surroundings.
• Maintenance Requirements: Consider the maintenance needs of the CNG compressor. Some compressors may have to be handled more frequently and require more routine checks than others. Choose a compressor that is easy to maintain, and consider the availability of spare parts and service centers.

Cng compressor Q & A

Q1 What is a CNG compressor?

A CNG compressor is a type of air compressor that increases the pressure of natural gas to three times the pressure of CNG. These large CNG gas compressors are typically used at natural gas extraction sites or pipeline interconnections. They are also used at CNG fueling stations and storage facilities.

Q2 How does a CNG compressor work?

A CNG compressor is similar to a regular air compressor. However, it has different mechanical parts designed to compress natural gas. The motor inside the CNG compressor rotates a shaft. The rotating shaft turns the impellers, which then suck in the gas from the inlet. The gas is compressed by the rotating impellers, and its pressure increases. The compressed gas is then discharged from the outlet.

Q3 CNG compressor types

CNG compressors are mainly used in two types: reciprocating air CNG compressors and rotary CNG compressors. A rotary CNG compressor is a positive-displacement screw compressor. It is made with two helical-shaped rotors. As the rotors turn and mesh into each other, the gas is trapped inside the cavity between the rotors and compressed.The reciprocating CNG compressor has a piston and cylinder mechanism. Whenever the piston moves inside the cylinder, it decreases the volume and increases the pressure of the gas. The working principle of both compressors is more or less the same, but their designs and methods of working are different.

Q4 CNG compressor applications

CNG compressors are commonly used applications in: CNG filling stations, CNG bus depots, CNG transit authorities, CN","G vehicle fleet refueling, CNG pipeline booster stations, CNG customer owned and operated fueling stations, CNG power plants, CNG industrial gas service, Mobile CNG compression services and CNG virtual pipeline service.CNG virtual pipeline service uses CNG compressors to transport natural gas toEnergy customers in locations where there is no natural gas pipeline

Q5 CNG compressor components

A CNG compressor contains the following major components: A gas cooler, A high-pressure separator, dehydrator, Filters, Purifier and a High-pressure compressor.The function of each component is to cool the gas, separate the condense liquid, remove moisture, filter impurities, and compress the gas.