How to restore and prevent pipe corrosion and scaling at a Sulfuric Acid recovery plant

Hydrex 2978 Neutral pH Cleaner

The Challenge

A Sulfuric Acid recovery plant was experiencing severe corrosion in their plant water supply piping. Two 2” galvanized supply lines feeding their production process were almost completely plugged, preventing water flow to the plant. The increased risk of an unplanned shutdown was unacceptable to the plant, and plans were developed to prevent this from happening.

Understanding how serious the situation was, and the costs associated with the lost revenue associated with any production shutdown, plant management had allocated a $1,000,000 capital project to replace the fouled piping.


The Solution

Veolia Water Technologies was brought in to analyze the situation and determine whether there were alternative approaches to an extended shutdown associated with the pipe replacement. Along with conducting a plant audit to better understand the situation, deposit samples were taken, and revealed the deposits to be comprised of 79% iron oxide.

In order to develop a solutions approach, a pilot study was conducted involving Veolia’s Hydrex 2978 neutral pH cleaner. A 12” sacrificial pipe from the system was used to conduct the pilot study. The results of the study were used to understand the impact of chemistry, time, temperature & pH on the deposit to be removed.

Process Description

The Pilot Rig test that was conducted showed significant success in removing the deposit from it’s surfaces, as can be seen from the Before & After photos to the right. A 20% solution of Hydrex 2978 was circulated through the piping for approximately 30 hours.  Due to the results received in the Pilot, a full scale Hydrex 2978 cleaning was set up. Veolia worked with Engineering to develop a pump skid system. 


Customer Performance Benefits


  • Heat exchanger water flow and efficiency restored
  • $1M Capital equipment replacement eliminated
  • Economical vs 3rd party cleaning companies.
  • Re-passivates metal surfaces

Safety & Environmental:

  • Minimal waste haul-out required
  • Less hazardous than acids, biodegradable
  • Safe to work with for employees
  • Easily monitored & controlled