Civil Engineering Reference
In-Depth Information
Furnace Stack
Stack Gas Supply Line
Wet Scrubber, Water Jet Impingement Type
Expansion Joints
or Flexible
Couplings
Three Water
Sealed CO
2
Compressors
Water Seal Supply
Line to Compressors
1,500
CFM
1,000
CFM
5 00
CFM
Strainer
Check
Valves
Expansion Joints
or Flexible
Coupling
Water Separator
Drain Line
Automatic Pressure
Relief Valve
T
Outside
Atmosphere
Pipeline
Orifice
Gas Flow
Manometer
Bypass
Line
Solenoid
Valve
Pneumatic Signal to
Valve Positioner
Pressure
Gauge
p
Controller
T
Atmosphere
Gate with
Positioner
Orifice Union
pH
Amplifier
Compressed CO
2
Supply Line
pH Electrode
Assembly
Drain Line
CO
2
Regulation Valves
Sample Line
Sample Pump
CO
2
Distribution Grids
Basin Influent,
High pH Water
Intermediate
Reaction or
Settling Basin
Basin Effluent
Recarbonated Water
Primary
Recarbonation
Basin
Secondary
Recarbonation
Basin
Fig. 13-6.
Typical recarbonation system using stack gas (From Culp, Gordon, and Williams,
Robert,
Handbook of Public Water Systems.
Copyright
1986 by John Wiley & Sons, Inc.
Reprinted by permission of John Wiley & Sons, Inc.)
Even in favorable locations, high cost is still the principal disadvantage of using liquid
CO
2
. Its advantages include flexibility, ease of control, high purity and efficiency, and
the smaller piping required because of its high CO
2
content, 99.5 percent, relative to
the 6 to 18 percent obtained from other sources.
Liquid CO
2
may be delivered to customers in insulated tank trucks ranging from
10 to 20 tons (9 to 18 metric tons) in capacity. Rail car shipments of 30 to 40 tons
(27 to 36 metric tons) are available to large-volume users. Some manufacturers will
lease tank cars so that they may be used for storage at the site, thus eliminating the
need and expense of bulk storage tanks and auxiliaries at the plant. For small plants,
liquid CO
2
is also available in 20- to 50-lb (9- to 23-kg) cylinders.
Bulk storage tanks may be purchased or leased. Capacities range from 1 to 100
tons (0.91 to 90.7 metric tons), although the common sizes are 4 to 48 tons (3.6 to
43.5 metric tons). Storage tanks must be insulated and equipped with Freon refriger-
ation and electric or steam vaporization equipment. The working pressure for storage
