pH Neutralization System for Acidic and Alkaline Waste Streams at Petrochemical Plant in China
Digital Analysis Corporation
CHEM-GARD Horizontal Centrifugal Pump
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Reprinted from PROCESSING Magazine
Material selection criteria for pH neutralization
system handling acidic and alkaline waste streams
When the designers of a sophisticated petrochemical manufacturing
plant in Neijing, China were faced with the various problems involved in
creating an environmentally safe, minimum maintenance, versatile
neutralizing system for handling corrosive and hazardous acidic and
alkaline chemical waste fluids under harsh outdoor service, they turned
to Digital Analysis Corporation of Skaneateles, NY, specialists in the
design of packaged and customized pH adjustment systems.
The criteria for the system included these difficult fluid handling
• The flow of the system is an average flow of 50 GPM with a peak flow
of 100 GPM;
• pH range from highly acidic (0.5) to highly alkaline (13.0);
• Temperature fluctuations from 50 degrees F to 150 degrees F;
• Total suspended small solids (salt precipitates) as high as 5,000 mg/L
The original specifications for this system indicated the use of type 304
stainless steel. Based on more than 20 years experience with highly
corrosive fluids in industrial processes, the engineers at Digital Analysis
concluded that the suggested metal would not be suitable, and that the
use of higher alloy materials or exotic metals was problematic and
costly. They recommended selected use of diverse thermoplastics for
the pumps, piping, tank and other fluid handling components. They
made these specific recommendations:
a) Polypropylene for the four horizontal centrifugal pumps. Digital
Analysis selected Vanton Chem-Gard® CGA units with all fluid contact
components (casing, flanges and impellers) furnished in solid, virgin
polypropylene and meeting ANSI B73.1 and international process pump
standards. (Figure 1)
b) Polypropylene for the custom-fabricated treatment tank.
Epoxy-coated steel reinforcement ribs, encapsulated in polypropylene
around the perimeter of the tank, provide additional wall support.
c) Chlorinated polyvinyl chloride (CPVC) for the pipes and fittings.
According to Richard Pinkowski, CEO of Digital Analysis, "In the opinion
of our engineering department, since this application involves exposure
to both highly acidic and highly alkaline discharge flows, and subjection
to sudden temperature and pH changes as well as harsh outdoor
conditions, no other materials of construction would offer the long term
reliability, safety and minimum maintenance required."
The installed system is able to rapidly neutralize hot caustic
concentrations — as high as 5 percent in a brief period of time — and
handle 98 percent sulfuric acid as it is injected into the caustic stream
which undergoes rapid and significant temperature elevation.
This spent chemical neutralization system was supplied as a completely
fabricated, skid mounted turnkey package (Figure 2). A polypropylene
containment drip pan with 8-inch-high walls, isolates the epoxy-coated
steel skid from potential leaks or chemical spills and provides for
drainage to a sump.
All recirculation, transfer and discharge lines were provided in solvent
welded CPVC scheduled 80 pipe, and all reagent delivery lines are made
of flexible PFA pipe double contained within a clear flexible PVC hose.
Since this system was designed to ensure minimum maintenance, is
economical to operate and easy to service, it was readily certifiable
under rigid Chinese standards.
Figure 2. Spent chemical pH
Neutralization System Custom Engineered
by Digital Analysis Corporation,
Skaneateles, New York.
In the 1950, Vanton developed a revolutionary all-plastic pump for use in conjunction with the first heart-lung device. The design limited fluid contact to only two non-metallic parts: a plastic body block and a flexible liner. This was the birth of our Flex-I-Liner rotary pump. Its self-priming sealless design made it an industry standard for the handling of corrosive, abrasive and viscous fluids as well as those that must be transferred without contaminating the product. Vanton now offers the most comprehensive line of thermoplastic pumps in the industry.
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(+44) 01260 277040
Vanton Pumps (Europe) Ltd.
Unit 4, Royle Park
Congleton CW12 1JJ