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Figure 1.

pH Neutralization System for Acidic and Alkaline Waste Streams at Petrochemical Plant in China





Wastewater Municipal

Digital Analysis Corporation

Acids, Alkalies

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.

Copyright 2016 - Vanton Pumps (Europe) Ltd - All rights reserved

About Us

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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