What Does Petroleum Coke Breeze Mean?
Petroleum coke breeze is a carbon backfill which is used around impressed current anodes for underground cathodic protection applications. It is used to:
- Reduce the resistivity of the environment surrounding the anode to increase the amount of current the anode can discharge
- Extend the anode surface area, thus increasing the amount of current the anode can discharge
- Reduce consumption of the anode since the carbon becomes the part of the anode consumed before the anode itself.
While the main purpose of coke breeze backfill is to reduce the anode-to- earth circuit resistance and to increase anode service life, it also helps to eliminate gas blockage and drying tendencies.
Corrosionpedia Explains Petroleum Coke Breeze
Petroleum coke breeze is a carbonaceous backfill material. Impressed current anodes are usually surrounded by a carbonaceous backfill to prolong anode life. To ensure good electrical contact, the backfill must be tamped around the anode.
Petroleum coke breeze can be used in both conventional and deep anode grounded to lower the resistance-to-earth and improve operating performance. The backfill has excellent pumping qualities and can be either mixed with water or installed as dry petroleum coke breeze, which is calcined to remove hydrocarbons and moisture.
Particle size and shape are also important when specifying a backfill. Both parameters determine the contact area between anode and ground while influencing the porosity of the column, which is important for gas ventilation. A general-purpose coke breeze is for use in shallow horizontal and vertical groundbeds. It has a resistivity of 35 W cm. For deep well applications a special calcined petroleum coke breeze is used. It has a resistivity of 15 W cm and can be pumped.
For impressed current cathodic protection systems in soil applications, petroleum coke breeze backfill is critical to the performance of the cathodic protection system. When installed around impressed current anodes, the coke breeze column, in essence, adds additional anode material to the cathodic protection circuit.