Storage and blow-down cylinder packs

Cylinder packs are arranged with cylinders positioned vertically and equipped with a drainage system to allow the emptying of any liquid that accumulates inside them. Cylinder packs can be installed in full or in part in the compressor room, in a dedicated room or outside on the forecourt, depending on the case in question and the regulations of the destination Country. Reasons for providing cylinder packs on the CNG system:

• Compressor blow-down volume: all or some of the cylinders are used for decompression when the compressor stops; the number of cylinders and therefore the volume to be dedicated to this purpose depends on the compressor model.
• Damping of pulsations: in systems where there is no storage, it is good practice to provide some cylinders on the compressor discharge to dampen gas pulsations that could be transmitted along the plant piping.
• Storage: in plants with a gas flow rate that varies during the day, providing for the storage of already compressed gas allows to:
  1. optimise the choice of compressor based on an average value. This avoids having to consider the peak time of sales during which the previously stored gas will be used.
  2. reduce the number of compressor start/stops. Storage can consist of one, two or three sectors (called low, medium and high pressure) depending on how many supply lines are required for the dispensers.
  3. maximise the use of storage by providing more supply lines to the dispensers and therefore storage sectors.

Main characteristics of cylinder packs

• Capacity of each cylinder: 80 litres
• Maximum operating pressure: 275 barG
• Manual drainage
• 1, 2 or 3 sectors (a blow-down can also be provided if necessary and requested)
• Shut-off valves for each cylinder (optional)
• Metal housing (optional)