VRU design basis

The following parameters are the base for sizing a VRU

Q(i) – Peak flow rate

Maximum loading flow rate reached by the Terminal.

  • Provides the pressure drop of the VRU and of the vapours collector
  • Determination of pipes & activated carbon filters diameter

NB: For future increase an antipatoon of this figure is very important

Q(4) – Throughput maximum in 4 hours

Maximum quantity loaded during the busiest period of the Terminal

  • Provides the vacuum capacity required

NB: Column size and absorbent circulation flow rate are directly related to the vacuum capacity, therefore to q(4)

Q(c) – Throughput maximum per absorbtion cycle

Maximum quantity of vapours to be loaded on the AC per adsorption cycle

  • Provides the Activated Carbon quantity per filter

NB: The cycle time if a fixed value and depends on the “type” of loading for an optimization of the filter vs vacuum pump capacity ratio: 12 min. for continuous loading operation, 15 min. for Truck bottom loading and 20 min. for top loading.

Q(d) – Throughput maximum per day

Maximum quantity of vapours to be treated in the busiest day of activity

  • Adjustment factor

HC% – Average HC concentration over a period of 4 hours

  • Size of the vacuum system