Petroleum coke is not considered hazardous—it has a low potential to adversely affect human health. * USEPA reviewed available analysis of petroleum coke and found no evidence that petcoke is a carcinogen or that it could adversely affect developmental or reproductive systems. Possible effects are generally limited to the respiratory system. These same effects are commonly associated with exposures to any dust particles and are not specific to petcoke.
Using proper techniques for managing dust and water run-off, Petcoke can be safely stored outdoors. Maintaining the optimum moisture content of petcoke is a key practice required to control petcoke fugitive emissions. There are three primary techniques for maintaining optimal moisture content and controlling potential petcoke emissions (referred to as “fugitive dust”) during storage:
• Pile maintenance
• Wetting with water
• Treating with an anti-dust chemical agent.
Pile Maintenance
Pile Maintenance is important as a method to control potential fugitive dust. Proper maintenance of petcoke piles helps reduce the potential for fugitive dust emissions, particularly when combined with wetting or anti-dust chemical agent practices.
The following steps are best practices for maintaining a petcoke pile:
- Pile height consistent with facility’s water application capabilities
- Shaping of the piles to remove peaks and sharp edges
- Pile compaction
- Reclaiming practices designed to reduce potential dust emissions
- Pile stacking practices designed to reduce potential dust emissions (e.g., minimizing drop height from stacking conveyors)
Wetting with Water
An emission control technique that is commonly used at petcoke storage locations is the application of water to storage piles. The systematic application of water to petcoke helps to control fugitive dust emissions and to maintain product moisture content. Water increases the particle weight and acts as a binding agent between particles. Water spray systems may require periodic reapplication of water to overcome the hydrophobic nature of petroleum coke.
Wetting systems for petcoke piles can include:
- Water cannons
- Water trucks
- Misters and aerial sprays
The most effective water application technology for an operation is dictated by site-specific conditions, but the primary considerations when selecting wetting equipment are:
- Ensuring the operation meets existing permit requirements
- Preserving the integrity of the product
- Maintaining optimal moisture content on a repeatable basis
Anti-Dust
Chemical Agent/Treatment
In some situations, water spray systems are combined with anti-dust chemical agents such as surfactants and humectants. Application of anti-dust chemical agents is normally achieved by combining the chemical into the water spray. The intent is to lower the surface tension of the water to allow droplets to penetrate deeper into the petcoke, and to slow moisture evaporation.
The use of anti-dust chemical agents may offer the following benefits:
- A residual effect of up to 45 days or more for pile integrity, depending on weather conditions and type of chemical used
- A minimized need for reapplication of water
- Additional coke pile height
- Reduced need for routine cleanup requirements of the coke conveyors
- Reduced maintenance needs within the coke handling facilities