Minimal Corrosion: Thanks to pH Control - METTLER TOLEDO
Application Editorial

Minimal Corrosion: Thanks to pH Control

Application Editorial
Process Analytics - "Application Note"

The installation of an intelligent in-line pH measurement with automated electrode cleaning allows for accurate control of sour water pH in Crude Unit Overhead Condenser Boot Water.

Sour water corrosion
Processing of sour crudes often results in serious corrosion problems in the top part of the crude column and condenser tubing. Due to the injection of steam in the column large amounts of water are generated. The crude itself contains contaminants such as sulfur, salts and gases. Dissolved in the produced water, these form a highly corrosive solution normally referred to as sour water. Since the rate of corrosion is largely depending on pH of the sour water, reliable treating and neutralizing is required.

An unsatisfactory situation
In the past our customer used standard pH measuring systems to control the chemical treatment of sour water. Large quantities of hydrocarbons, also present in the process, continuously affected the pH electrode and lowered its performance to such an extent that the customer decided to discard the measurement and turn to testing in the laboratory.