Since the purpose of the carbonaceous backfill is to provide an electronic path for current flow, low resistivity, particle size, and specific gravity are important backfill properties. Low resistivity favors electronic current flow to the backfill / ground interface. Small particle size and high density favor electronic current flow between the anode material and backfill by improving contact between the anode material and the backfill.

• Asbury 218-L Backfill is an industry standard calcined petroleum coke. It is a perfect choice in situations where backfill must be top loaded. The density and angular nature of Asbury 218-L allow it to settle quickly into position. Asbury 218-L is a coarsely screened product. The large size of the particles ensures that the backfill will be permeable to gas even in situations when over-compaction has taken place.
    
• Asbury 218-R Backfill is a finer grade of calcined petroleum coke than used in Asbury 218-L. It is the best choice in situations where the backfill must be top loaded into a smaller diameter well. The density and angular nature of Asbury 218 Series cokes allow them to settle quickly into position. Asbury 218-R provides good gas permeability due to a low fines content. It is suitable for both conventional and deep well systems.
    
• Asbury 251 Backfill is a calcined fluid petroleum coke, superior to breeze coke in density and resistance. The spherical particle shape is optimum for slurry applications. The high density ensures that the backfill will pack tightly when either pumped or top loaded. The backfill flows around the anodes, leaving no voids or pockets. Asbury 251 Backfill is the logical choice for deep well systems as well as for conventional ground beds.
    
• Asbury 251-P Backfill is a calcined fluid petroleum coke manufactured to provide the lowest possible resistance for a calcined fluid coke. Asbury introduces a conductive additive during the production process, which lowers resistivity and improves the wetability of normal Asbury 251 Backfill. Asbury 251-P is the superior choice for backfill in critical deep well or conventional ground beds when low resistivity is the major consideration.
    
• Asbury 4518 "Flo Coke" Backfill is a spherically shaped petroleum coke. It is very dense, which promotes settling when used in deep well systems. The particles are very resistant to crushing forces, making it one of the hardest products available to the corrosion protection industry. The high density and particle hardness make 4518 "Flo Coke" a candidate for top-loading deep wells and for conventional ground beds.

Use for Ground Beds & Deep Wells

Packaging: Asbury Carbon Backfills are available from Farwest in 50 lb bags on 2500 lb pallets. They are also available on request in one-ton super-sacks, in drums, or in bulk. Please contact Farwest for special packaging requirements.