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ITEM QUANTITY

Cartridge Filters 2x100%
2x100%
Membrane Contactors Skid
(10 contactors operating in parallel)
Liquid Ring Vacuum Pump 2x100%
Preassure Swing Adsorption 2x100% adsorbent vessels;
Nitrogen Generation Skid 1x100% receiver vessel membrane contactors is lower (67 mbar) if com-
1x100% pump; 1x100% tank; pared with both the pressure levels that should be
CIP Skid guaranteed in the first (42.9 mbar) and the second
1x100% Cartridge filter
Instrumentation and Local Included (9.7 mbar) vacuum towers stages to gain the same
Control Panel performance. In fact, the lower applied vacuum is
compensated by the use of Nitrogen stream in the
Piping, Valves and Wiring Included removal of oxygen from water. Plants components
of both vacuum towers and membrane deaeration
Table 3. MDA Module Scope of supply project are summarized in Table 3 and Table 4.
Results show that membrane deaeration allows, at
the same operative conditions, better performan-
ITEM QUANTITY
ces than the vacuum towers (Table 5). Moreover,
Vacuum Deaeration Tower 1x100% the membranes are the valid alternative to the va-
cuum towers in the case that very low oxygen con-
Vacuum Generating System 1x100% pump, 1x100% ejector centrations are required and/or when the adoption
of chemicals such as oxygen scavenger is not pos-
Injection Booster Pump 1x100% booster pump
sible or not available.
Biocide I Chemical Dosing Skid 1x100% pump, 1x100% tank
Biocide II Chemical Dosing Skid 1x100% pump, 1x100% tank 4.2 Footprint, volumes, weights
Antifoaming Chemical and other aspects of comparison
Dosing Skid 1x100% pump, 1x100% tank
Oxygen Scavanger Chemical In addition to the previous analysis in terms of per-
Dosing Skid 1x100% pump, 1x100% tank formance, the two treatments were also compared
Instrumentation and Local in terms of overall size (footprint and volume) and
Control Panel Included weight (Table 6). This information is very important
in order to evaluate any equipment limitations du-
Piping, valves and Wiring Included
ring in site installation. In such cases, where there is
limited space for installation, it could be very impor-
Table 4.Vacuum Tower Scope of supply tant to have compact and/or low height equipment.
In other cases, a limitation on equipment weights
TREATMENT MDA VT can be applied as in the case of oil & gas offshore
Unit of sites.
Parameter The calculation of volume, footprint and weights
Measure in vacuum towers project included the following
Design Flow rate 92.5 92.5 m /h equipment: vacuum tower itself, vacuum genera-
3
tion system, Chemical skids and Booster pump
Nitrogen Purity 99.99 NA %
skid. In the case of Membrane deaeration systems,
Quantity of contactors 10 NA - the calculation included the following equipment:
in parallel Membrane deaeration, vacuum generation sy-
stem, Cleaning in place skid (CIP) and Nitrogen
Operative Temperature 4 4 °C
Generation system. As for the costs comparison,
Vacuum level 67 42.9/9.7 mbar the equipment and/or the instruments which were
common to the VT and MDA systems were not in-
Gas (Nitrogen) sweep 1.6 NA Nm /h
3
rate per contactor cluded in the comparison such as the Dual media
Filters and the feeding pump. The evaluation were
3
Vacuum Load 321.8 319.0 m /h made by the help of the 3D models of the two sy-
Inlet dissolved Oxygen stems, MDA (Figure 5) and VT (Figure 6).
(Saturation @ T) 13.8 13.8 ppm Results show that the deaeration plant based on
the utilization of VT has size comparable with that
Flow rate per 3 of the equivalent project using MDA (both foot-
contactor 9.2 NA m /h prints are about 33 m ) while volume of VT project
2
Filtration> 98% Filtration> 98% is slightly higher (90 m ) than that in case of MDA
3
Pretreatment
@ 2 μm @ 2 μm (71 m ).
3
Maximum Dissolved 6.9 50 ppb Also the weight of the vacuum tower system is
Oxygen (DO) higher (28 Ton) than that of membrane contac-
tors’project (10.2 Ton). Moreover, the innovati-
Total sweep gas 3 ve deaeration system based on the membrane
(Nitrogen) 16.1 NA Nm /h contactors implies lower volume as well as lower
weights.
Table 5. Performances comparison between MDA and VT In order to close the comparison between the

Impiantistica Italiana - Luglio-Agosto 2017 69