Process Description
Hydro-Flo batch pH adjustment systems are designed to
accept batches ranging in volume from 50 to 10,000 gallons. In order
to allow for fluctuating flow rates and system surges a primary
equalization tank (or main collection sump) is recommended. A level control (typically
single set point level switches or as an option an
ultrasonic or continuous output bubbler level sensor) is used in the equalization tank and the treatment tank. A Programmable Logic
Controller (PLC) within the Main Control Panel (MCP) monitors the
tank levels. When the level rises above the 10% full mark, a
recirculation / transfer pump is started. If the treatment tank is
empty, the equalization system automatically transfers a batch to the treatment tank
(if it is available). Once the treatment tank fills
to the high level, the transfer from the equalization tank stops and
the equalization tank reverts back to the recirculation mode. The
treatment tank then treats the tank contents using "Continuously
Variable Batch Treatment" technology, developed by Hydro-Flo. Once
the reaction tank contents reach the pH set point, the contents can
be transferred to the process stream or directly to sanitary sewer.
When the treatment tank descends to the 10% full level, transfer from
the first stage equalization resumes and the process repeats.
NOTE:
A pretreatment option is
available for the equalization tank. This option allows for coarse
treatment of the equalization tank contents.
The Equipment:
The basic system is
comprised of a skid, reaction tank, reagent storage tanks, valves,
plumbing, a mixer, chemical metering pumps,
and a
control panel.
Skid:
A steel skid is provided for supporting the
entire system. The skid features a welded 4" steel "C" channel
frame and a 1/4" steel deck plate. The entire skid is blasted to an
SSPC-SP6, and coated with a 2 part, self priming epoxy finish for
corrosion resistance. The skid color is OSHA Safety Blue,
unless otherwise specified.
Optional Containment Pan: As an
option, a containment / drip pan can be provided for protecting
the steel skid from leaking or spilled corrosive fluids. A drain
connection is provided for plumbing the containment pan to a
suitable location. The pan can be fabricated from polypropylene,
stainless steel, etc. and features 8" high walls.
Reaction Tank:
There are many items to
consider when choosing the reaction tank. What are your batch
sizes expected to be? How much do you generate daily?
What is your peak flow? What chemical processes are going to
be applied? Will the reaction be exothermic (create heat)?
If so, how much heat will be generated?
Hydro-Flo addresses all
of these items, as well as others, in order to properly size the
system and choose the correct materials of construction for the
application.
Typical Poly Reaction Tank: The
reaction tank is manufactured of HDPE polypropylene. The tank
is designed for fluids with a s.g. of up to 1.9 with a safety
factor of 2:1. Destructive burst testing has shown that tanks of
this construction often have an ultimate load safety factor
exceeding 3:1. If positive ventilation is used, the tank is rated
to +/- 20" w.c. The top will support all mounted equipment and
the weight of one 200 lb. man without significant deflection.
NOTE: The system detailed here
is fabricated from polypropylene. Polypropylene is
typically used for long service life and superior corrosion
resistance. As an
option, we can fabricate the system from any commercially
available material including epoxy
coated carbon steel, stainless steel, FRP, exotic alloys and
all thermoplastics.
Reagent Storage Tanks:
Chemicals for treatment are pumped directly
from 55 gallon DOT drums. An alternate to pumping directly
from DOT drums is utilization of day tanks which can be
automatically refilled from the customer's bulk chemical delivery system
within the plant. Redundant level sensors and redundant fill valves
provide protection against overfilling.
Valves:
All ball valves are true union, field
serviceable valves. All diaphragm valves are flange mounted. Elastomers are EPDM and Teflon, except on concentrated acid lines
where the elastomers are Viton and / or Teflon.
Plumbing:
All recirculation, transfer and discharge
lines are fabricated from solvent welded, PVC SCH 80 pipe. All
reagent delivery lines are flexible PFA tube, double contained within
a clear flexible PVC hose, clamped at each end to seal leaks.
Mixer:
The mixer is one of the
key elements of the system. The system will not generate
consistent results without a properly sized mixer. Typically,
mixers are sized to turn over the tank contents at a rate not less
than 2 times per minute.
Chemical Metering Pumps:
Properly sizing the
chemical metering pumps is important in order to achieve the correct
chemical reactions. Also, metering pump sizing has an impact
on total chemical consumption. Properly sized pumps will help
you reduce overall chemical costs.
Control Package:
All Hydro-Flo batch treatment systems are fully automated.
Control packages (depending on your specific requirements) are
available in either basic relay logic controls or a full state of the art
PLC
with touch screen HMI and our
sophisticated treatment algorithms. The relay logic controls
package allows basic reconfiguration of the original system settings,
while the PLC based package allows maximum flexibility
to change the process parameters, as well as tight control that
minimizes chemical usage. We can include a variety of options
including digital data logging of critical
process parameters, ethernet access to process data, communication
with Building Management Systems, and even remote system access
using cellular wireless technology.
All enclosures are NEMA 4X.
Where metallic
enclosures are used, they are provided with epoxy or polyester
finishes for corrosion resistance. All conduit is plastic coated,
where possible. Low voltage 24VDC is used throughout to minimize
service personnel exposure to high voltage. All panels are OSHA LOTO
and NFPA 79 compliant. UL-508 listing is available.
Effluent Monitoring: As mandated by
the local controlling authority, the effluent quality must be
continuously monitored. A two pen recorder is to be used to
monitor effluent flow rate and pH. The recorder is to be
equipped with a flow totalizer. Any effluent pH deviations will
trigger an alarm and system discharge will be halted.
System Packaging:
The system is supplied as a completely
fabricated "turnkey" package. All devices are pre-wired and plumbed.
You need to make the plumbing connections to
and from the system and a single electrical connection point for
incoming power. The disconnect on the MCP provides OSHA Lock
Out / Tag Out and NFPA 79 compliance. Systems requiring
compressed air, also require only one connection and the valve is
supplied for OSHA LOTO.
Additional Information
For specific equipment information, contact us
directly. We can provide the specifying engineer with a formatted
specification package that thoroughly describes any of our systems
for bidding purposes. This includes detailed drawings, and detailed
equipment specifications.
Batch
pH Adjustment Systems