OR-1000™: Next Generation System for Oxidizing and Corrosive Chemical Storage

One of the challenges in storing any oxidizing chemical is engineering a chemical storage tank that not only contains the chemical but has a greater life expectancy and measure of safety. Whether you’re storing sodium hypochlorite, sulfuric acid, hydrochloric acid, or other oxidizing substances, it is critical to design the storage tank with the chemical in mind.

Poly Processing Company (PPC) has been a leader in rotationally molded crosslinked polyethylene (XLPE) storage tanks for 50+ years. PPC works with leading universities and chemical manufacturers and suppliers to develop engineered polymer systems that perform above and beyond any standard off-the-shelf polyethylene tanks — especially in harsh, oxidizing environments.

One of the chemical storage innovations we’ve developed is the OR-1000™ system. This system is the result of an initiative aimed at defining and addressing the long-term failure mechanisms associated with polyethylene when storing strong oxidizers and other corrosive chemicals. 

The OR-1000™ system consists of engineered resins for oxidizing applications to provide superior environmental stress cracking resistance (ESCR).

What is the OR-1000™system?

The OR-1000™ system is an engineered resin with four times the antioxidant power of a standard tank wall. Poly Processing’s exclusive OR-1000™ system was specifically designed to address the aggressive oxidation effects of hazardous chemicals such as sodium hypochlorite, sulfuric acid, and hydrochloric acid. It does this by adding an additional resin system between the XLPE and the chemical.

The OR-1000™ is designed to maximize the useful life of storage tanks in oxidizing environments. This system greatly increases the life of a crosslinked polyethylene tank, giving you a much more cost-effective solution.

OR-1000™’s engineered resin system is made of polyethylene that is specifically formulated to resist oxidation by corrosive chemicals. Its outer surface is made of XLPE for superior strength. Its inner and outer surfaces are molecularly bound together during the roto-molding process, creating a truly seamless bond between the XLPE and OR-1000™ system.

Long Term Improvements

The OR-1000™ system’s resistance to oxidative degradation is illustrated in the chart below. This chart compares the tensile elongation of the OR-1000™ system and two different commercial rotational molding polyethylenes when exposed to 12.5% sodium hypochlorite (industrial strength bleach) solution at 40 degC. Sodium hypochlorite is one of the strongest corrosive chemicals that oxidizes polyethylenes.

After nine months of exposure to sodium hypochlorite, the conventional polyethylene tanks have lost an average of 30% of the original tensile elongation to break. During that time, the OR-1000™ has lost only about 3%. This indicates that the OR-1000™ has about 10X greater resistance to oxidative degradation. 

Loss of elongation in this manner indicates an increasingly brittle tank or liner — and thus a greater susceptibility to cracking and leaking over time. 

The data clearly demonstrates the superior long-term performance of the OR-1000™ system for storing strong oxidizing chemicals such as sodium hypochlorite.

Environmental Stress Crack Resistance (ESCR)

Polymers such as polyethylene are especially susceptible to another type of failure known as environmental stress cracking (ESC). Stress cracking occurs when polymer chains start breaking in stressed areas of a tank. Examples of stress include normal heating and cooling of storage tanks in outside environments or pressurized filling and emptying of transfer tanks used in chemical manufacturing.

The stress cracking process is accelerated by storing solutions of hazardous chemicals, particularly dilute solutions in which the chemicals have increased mobility and can physically penetrate the polymer structure and increase the stress differences. 

The chart to the right shows the difference of ESCR in tanks with and without OR-1000™.

Real World Benefits of the New OR-1000™ System

The OR-1000™ system has an impressive track record with our customers, providing these real-world benefits:

• Improvements in the long-term properties: The enhanced resin lasts longer and allows your tank to last longer as well.
• High levels of Environmental Stress Crack Resistance (ESCR): High levels of resistance to environmental stress cracking in the presence of Sodium Hypochlorite and other aggressive chemicals.
• Improved Elongation: The OR-1000™ system maintains its elongation properties over time while in the presence of heavy oxidizing chemicals. This performance is superior to other HDPE materials commonly used in tank construction.
• NSF/ANSI 61 – Poly Processing Company XLPE tanks with the OR-1000™ system are NSF certified for 35 different chemicals.
  

To learn more about the Next Generation OR-1000™ system, contact us.