Cathodic Protection |

What is Cathodic Protection?

Corrosion is a natural process that can deteriorate metal structures and cause costly damage for your business.

Cathodic protection is routinely used to protect equipment operating in aggressive environments from corrosion. The two most common applications of CP are for buried pipeline systems and vessels as well as offshore platforms.

Cathodic Protection (CP) is one of the most effective methods for preventing most types of corrosion on a metal surface. In some cases, CP can even stop corrosion damage from occurring. Metals, especially ferrous metals, corrode in the presence of oxygen, water, and other impurities such as sulphur.

Without CP, metals act as the anode and easily lose their electrons and thus, the metal becomes oxidized and corroded. CP simply supplies the metal with electrons from an external source, making it a cathode.

There are two basic types of CP systems: galvanic (or sacrificial) and impressed current.

How it works:

Impressed current cathodic protection systems have the benefit of using an external power supply to drive current. This makes it possible to protect virtually any structure, regardless of size or current requirements using long life anodes and enough appropriately sized power supplies.

The process:

Petrotrack undertakes soil survey measurements to determine resistivity values.

Based on these values , the type of pipe coating provided on the buried pipe section a CP system is then chosen. The Cathodic Protection criteria for such underground pipeline installation is defined in The BS 7361 Part 1: 1991 CATHODIC PROTECTION – Code of practice for land and marine application :- All the CP protected steel pipeline must attain an instant ‘OFF’ potential of –ve850mV as measured to earth referenced to copper/copper sulphate electrode in normal soil without anaerobic bacteria. The ON/OFF timing could range from 0.1s to 4s. The instant OFF potential is taken for determining Cathodic Protection presence. All steel pipeline sections with potentials more positive than –ve850mV are considered to be in the corrosive range.

Our Projects in Cathodic Protection:

Among projects undertaken by Petrotrack recently include,

Remediation of the CP system at Entebbe airport, Uganda for EJAFS.
New CP system for the extension by 1.8 KM of the aviation fuel hydrant at Jomo Kenyatta Airport in Nairobi.
Installation of a CP system at AGOL depot in Mombasa covering both buried pipeline in soil and in sub marine section to a floating barge
Shimanzi Oil Terminal in Kilindini port to Shell terminal in Shimanzi, 6 nos. pipelines, the VTTi terminal in Kipevu to Kenya Pipeline depot PS 14, 20-inch interconnection pipeline in Mombasa
Oilibya Terminal in Shimanzi Mombasa to Shimanzi Oil Terminal in Kilindini port, 8 inch base oil pipeline.