Question 13: How is the pressure tank for hydrogen filling stations arranged?

Answer: A pressure tank, sometimes also a pressure buffer, consists of a group of stationary pressure vessels connected in parallel. These vessels can be connected in a cascade depending on the pressure (eg 450 and 900 bar). At each stage of the cascade, the vessels can be divided into sections. This division is tasked with increasing the productivity of the high pressure hydrogen supply and thus optimizing both the size and the cost of the equipment.

The used pressure vessels must be compatible with hydrogen in accordance with the ČSN EN 11114-4 standard. Individual stages of the cascade or their sections must be equipped with automatic shut-off valves that cut off the hydrogen supply in case of abnormal operating conditions or in case of danger. Each section of the tank must be equipped with a separate shut-off and safety valve.

The calculation of the size of the pressure tank is carried out in accordance with the SOW, depending on the required one-moment filling power of the station, when the rated power of the hydrogen compressor does not correspond to the filling rate. In practice, this means that the process of filling road vehicles with hydrogen takes place in the form of high-pressure transfer of hydrogen from tanks through a dispenser to the vehicle tank. And the compressor replenishes the supply of hydrogen in the high-pressure tank in the intervals between individual vehicle refuelling.

A high-pressure hydrogen storage tank is usually located in an open, ventilated area, which is the best and least expensive solution from a safety standpoint. The distance from filling devices must be at least 8 meters.