CNG Cylinders: Types, Benefits, and Safety Guidelines

Compressed Natural Gas (CNG) has emerged as a cleaner and more sustainable alternative to traditional fuels, making it increasingly popular across industries and transportation. However, a medium is required to store and dispense this flammable gas and thus CNG cylinders are introduced. These cylinders come in various types, each tailored to specific applications while offering numerous benefits to users. And, to explain CNG cylinders comprehensively, this guide is curated. It covers types of CNG cylinders, their advantages, and crucial safety guidelines to ensure optimal performance and risk-free usage for both individuals and industries.

A] What Are CNG Cylinders?

CNG cylinders are robust and highly secured mediums for storing compressed natural gas (CNG) with high pressure. These high-pressure seamless steel gas storage tanks are made from different metals or composite materials to endure a filling pressure of 150 to 300 bar. CNG cylinders are used in an array of applications, including fuel for vehicles, power generation, air conditioning, medical, and other industrial processes. With CNG cylinders, individual users or industries can rest assured for 15 to 20 years, they are engineered to last longer. 

B] Types of CNG Cylinders

Type 1: All-Metal Cylinders

As the name suggests, type I CNG cylinders are all metal cylinders made from steel to store CNG gas at high pressure (up to 300 bars). The full metal body construction allows type I CNG cylinders to pass all safety checks and associated compliances, ensuring you never encounter unforeseen events. They are highly economical and can be used efficiently for a variety of purposes, including scuba diving, laboratories, and modified atmosphere packaging (MAP). In addition, type I CNG cylinders are highly suitable for high-volume industrial and static applications. Other than that, this CNG cylinder type is extensively used in a variety of industries, including F&B, transportation, logistics, and power and industrial production. 

Type 2: Hoop-wrapped Composite Cylinders

Type II hoop-wrapped composite cylinders are constructed in two layers, the first layer is made from the metal liner (typically steel), and the other layer wraps the first layer with composite material (generally carbon fibre). The two-layer construction provides added strength to the cylinders and makes them withstand high pressure. These types of cylinders are widely used for medical purposes, laboratories, and other industrial and general purposes. 

Type 3: Fully Wrapped Composite Cylinders with Metal Liner

Type III CNG cylinders are upgraded versions of type I and II. It is made from a very thin layer of the metal liner, and a layer of composite materials is wrapped above the base layer. Due to the extensive use of composite materials, type III cylinders are lightweight CNG cylinders. They are extensively used for medical purposes, fuel cell applications, aerospace, and military applications. Other benefits of type III CNG cylinders are: lightweight, impact-resistant, heat-resistant, chemical-resistant, and durable. 

Type 4: Fully Wrapped Composite Cylinders with Plastic Liner

Type IV CNG cylinders are the advanced version of type III cylinders made from non-metallic polymer liners and wrapped with carbon fibre, making them extremely lightweight. The advanced construction technique is utilised in manufacturing type IV cylinders, making it future-ready for various general and industrial applications. 

C] Benefits of CNG Cylinders 

• Safety Benefits: Due to the narrow flammability range and high ignition temperature (upto 540°C), CNG cylinders are known to be the safest containers for storing CNG gas. They are engineered to be structurally sound, making them highly safe and suitable for transportation as well as rigorous use. 
• Low Operation Costs: Due to the high life expectancy (up to 20 years) and intuitive transportation capabilities, CNG cylinders are extremely cost-effective when it comes to operational costs. 

• Seamless Transportation: Due to being made from special metal alloys and composite materials, these CNG cylinders are designed to handle the intricacies of transportation. Top cylinder manufacturers, like Rama Cylinders, design cylinders’ ergonomics in such a way that provides seamless transportation requirements.

• Controlled Gas Supply: Due to the integration of the robust and highly efficient gas regulation system, CNG cylinders are known for their controlled gas dispensing and supply.  

D] CNG Cylinder Safety Measures

Though CNG gas has a narrow flammability range, users should always keep in mind that it is a flammable gas. Therefore, below are the CNG cylinder safety standards or measures which must be followed during the storage, use, and transportation of CNG cylinders.

• Use of approved CNG kit & Cylinders: It is suggested that users always use globally approved CNG cylinders and verify and test CNG kits to mitigate any unforeseen events. Substandard CNG cylinders and kits are less reliable. 
• Don’t Store Gases Other Than CNG: Refrain from using CNG cylinders to store other gases instead of CNG gas as they are not Biogas cylinders. Doing so deteriorates the structural integrity of the CNG cylinder. 
• Avoiding Dropping and Collisions: Always avoid deliberate dropping and collisions with other cylinders and surrounding items. It affects the structural integrity of cylinders and may deteriorate mounted valves and regulators. 
• Safe Cylinder Movement: Always use a hand truck, fork truck, roll platform, or similar device to move CNG cylinders within the premises. Users should always refrain from dragging and sliding to maintain their workability and lifespan. 
• Regular Inspection: It is suggested that users should regularly check their CNG cylinders’ conditions. If it is found faulty or damaged, it should be rejected or abandoned. 

E] Tips for CNG Cylinder Maintenance 

• Regular Maintenance: Regular maintenance is essential to ensure CNG cylinders are in the best condition. It should include some tests like hydro-test, leak test, damage inspection, and valve inspection. If any part is found faulty, it should be replaced with verified and compatible parts. 
• Frequent Safety Checks: Frequent safety checks ensure CNG cylinders are secured and ready to use in harsh environments. Every cylinder should be checked every three years by a government-approved cylinder testing agency. 
• Adopting Best Handling Practices: Adopting best handling practices is one of the prominent CNG cylinder maintenance tips, involving using appropriate handling tools and fleet to move cylinders. 
• Arranging Fire Safety Around: It is essential to incorporate fire safety arrangements, such as fire alarms, fire resistance walls, and conspicuous signs to prevent smoking, open lights, and fire flames. 

Conclusion

CNG cylinders are an integral part of transportation, manufacturing, and other various industries. It offers a combination of efficiency, safety, and affordability. Understanding the different types of CNG cylinders and adhering to safety guidelines is essential to maximise their benefits while minimising risks. By choosing the right cylinder type and implementing best practices for usage and maintenance, users can ensure a reliable and safe utilisation of CNG cylinders.

If you are looking for a top and one of the largest cylinder manufacturers to fulfill your CNG cylinders procurement needs, Rama Cylinders is here to help you. Contact us today to get tailored CNG cylinders specially designed to fulfill your individual or industrial requirements.