Cascade Construction & inspection, handling, storage and all other relevant aspects of cylinders and fittings are as per ‘The Gas Cylinder Rules’ and are approved by Chief Controller of Explosives (CCOE). Cylinders are mounted on a robust frame structure which does not allow lateral / rotating movement of cascade in any condition. All cylinders are subject to a hydraulic stretch test at a minimum pressure of 422 bar or to pressure as determined and approved by CCOE and as required under rules 2004 . All cylinders are provided with safety relief device consisting of fusible burst disc assembly as approved by Chief Controller of Explosives (CCOE). The burst disc discharge is manifold to a common header for safe venting. All cylinders are periodically examined & hydro tested every three years as per ‘Gas Cylinder Rules.
Natural gas is compressed at 250 Bars with the help of Reciprocating compressors. After compression it known as Compressed Natural Gas (CNG). At Mother or Online Station, it stored in a cascade which is a bunch of cylinders. bunch of cylinders arranged systematically on an iron structure. These cylinders are made by Iron, Aluminum lined, carbon fiber wrapped material make with a specific standard and process. Each cylinder is manufactured and tested as per stringent guidelines of PESO. Cylinders are well placed at a defined distance from each other and fitted with SS tubes of SS-316/316L Grade with suitable fitting confirming ASME A 269. Stationary cascade are made with three storage bank system with Non Return valves. These are Low, medium and high banks. This bank system are used as per convenience or requirement for CNG dispensing. Isolation valves at each cylinders and safety relief valve provided to ensure safety.
Type-1 Cascade
Cylinders used in Type-1 cascade must designed, constructed and tested as per IS 7285 latest version or BS 5045 : Part-1 or (US) D.O.T 3AA as confirmed by PESO. Cylinder material must be seamless alloy steel (Cr-Mo), neck threading must be as per IS: 3224 – 1979, thread must confirming IS: 3224-1970. Shut off valve must confirm IS: 3224. Type-1 cascade are popular in Indian City Gas due to its cost. These can be used as stationary or mobile cascade to carry CNG from Mother station to Daughter booster stations.
Type-2 Cascade
This is a metal cylinder (steel or aluminum) with a partial wrapping that goes around the cylinder. The wrapping is usually made of glass, or carbon, contained in an epoxy or polyester resin. This design weighs less than the type one and costs more.
Type-3 Cascade
These are metal liner cylinders with composite reinforcement wrapping on full exterior with fibers applied in full hoop/circumferential and helical/axial portions. These are also two types. One made with full carbon composite and another is with mixing of carbon composite and glass fiber wrapping. These are compliant of NFPA 52 standards. These cylinders are used to made cascade of lighter in weight and to carry more quantity of CNG. These truly mobile cascade. These are costly.
Type 4 Cascade
Cylinders are HDPE with Carbon fibre composite. Due to this combination, cylinder are ultra light with capacity to store maximum quantity of CNG. Type-4 cascades are capable enough to replace Type 3 and Type-1 use for mobile cascade. These cascade confirms ISO : 11439, ISO 11119-3 & ECE 110 RO2
Parameters in Details
|
Mobile Cascade details
|
Type-1
|
Type-1
|
Type-3
|
Type-4
|
|
Cascade capacity (Water liters)
(Approx.)
|
3000
|
4500
|
9000
|
9000
|
|
Cascade Dimensions (meters) (L X I
ON) (Approx.)
|
3.5 X 1.87 X 1.93
|
5.25 0 1.87 X 1.93
|
2.99 X2.43 X2.59
|
5.24%1.9 %2.4
|
|
Cascade weight (Approx.) (MT)
(Approx.)
|
6.
|
9.
|
6.50
|
5.
|
|
CNG weight 0 255 BARS (MT) @ 15C
(Approx.)
|
0.538
|
0.806
|
2.
|
2.
|
|
Total Weight (Cascade a CNG) (MT)
(Approx.)
|
6.
|
10.
|
8.
|
7.
|
|
Ratio (CNG filled to Cascade
Weight 'V)
|
9.%
|
9.%
|
2080%
|
44.%
|
|
GVW and Payload of CNG Trucks in
India'
|
GVW-10.9 MT
Payload-6.8 MT
|
|
GVW-14.2 MT
Payload-9.4 MT
|
GVW-14.2 MT
Payload-9.4 MT
|
|
GVW and Payload of HOD Trucks in
India'
|
|
GVW-14.2 MT
Payload-9.4 MT
|
|
|
|
Truck dimensions (Meters) (L X B)
|
5.15 6 2.25
|
5.8 X 2.45
|
5.8 6 2.45
|
5.8 X 2.45
|
