Cathodic Protection Coke Breezes
Impressed current anodes are usually installed on horizontal or vertical shallow anode beds (when there is no environmental constraint) or deep well anode beds (when subjected to dry desert environmental conditions). In all of the above conditions, the anodes are surrounded by a low resistivity carbonaceous backfill, which increases the lifetime and performance of the anodes by reducing the resistance between the anode and the ground.
In IPS-M-TP-750 standard introduces three types of carbonaceous backfill materials that contain high amounts of carbon (80% metallurgical coke, 90% petroleum coke and 95% special petroleum coke). Type 1 coke (80% metallurgical coke) must have high resistivity and low ash content. Type 2 coke (90% petroleum coke) is calcined (heat treatment) to remove petroleum products other than carbon and must be granular. Type 3 coke (95% special petroleum coke) will also be specifically calcined (heat treatment) to remove other petroleum products other than carbon. The product shall contain 0.1% moisturizing agent to increase the rate of grain formation and water absorption of the backfill. The resulting grains shall be round and not crushable.
Comparison of chemical and density properties of three types of cathodic protection coke
|
Chemical Properties (wt%) |
Type 1: Metallurgical Coke Breeze |
Type 2: Petroleum Coke Breeze |
Type 3: Special Petroleum Coke Breeze |
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|
Content |
Density (kg/m3) |
Content |
Density (kg/m3) |
Content |
Density (kg/m3) |
|
|
Carbon (Min.) |
80 |
650-800 |
90 |
700-1000 |
95 |
1050-1200 |
|
Moisture (Max.) |
5 |
5 |
1 |
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|
Ash (Max.) |
15 |
5 |
3 |
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|
Total Sulphur (Max.) |
1 |
5 |
1 |
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|
Volatile matter (Max.) |
5 |
5 |
1 |
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Comparison of the grading of three types of cathodic protection coke
|
Particle Size
|
Type 1: Metallurgical Coke Breeze |
Type 2: Petroleum Coke Breeze |
Type 3: Special Petroleum Coke Breeze |
|
Less than 10 mm 100% Greater than 1 mm 90% |
100% Less than 3 mm 100%100 90% Greater than 0.5 mm 90% |
Less than 1.0 mm 100% Less than 0.6 mm 80% Greater than 0.4 mm 90% Greater than 0.15 mm 99% |
According to the IPS-M-TP-750 standard, the resistivity of coke type 1 and 2 shall be less than 100 ohm.cm and the resistivity of coke type 3 shall not exceed 0.1 ohm.cm. Under the same conditions, Coke type 3 is of better quality and will perform better due to the low resistivity.
In order to protect the cokes from environmental factors, they are packed in double-walled bags of 25 kg or 1 ton. Coke moisture retention is particularly important during packing and storage until use on site.
Borna Electronics Co. declares its readiness to supply all types of cathodic protection coke breezes based on the requests of respected clients or project needs.
