Crude Distillation Unit
1. Water Wash
Problem: Understanding how to effectively inject wash water in most efficient placement to dilute acid that has formed in the liquid phase and dissolve salt deposits.
Best practice: Invest in a CFD study to validate performance before beginning injector design. Using flow rate and pressure drop to determine injection points is not enough. Using quills instead of spray injectors will likely create excess free water that will not properly interact with the vapor stream and may cause erosion and other corrosion issues.
2. Filming Corrosion Inhibitor
Problem: Provide a protective barrier, a film, on the inside of the overhead line
Best practice: WhirlJet® Hollow Cone spray nozzles are available in low flow capacity sizes and can be operated at lower pressures to maximize drop size and filming effectiveness. The hollow cone spray pattern directs the filmer to the pipe wall.
3. Neutralizing Amine
Problem: Injection system that is ineffective that can lead to wasted chemical and possible corrosion on overhead piping due to neutralizer that is not volatilized
Best practice: Using a spray injector designed specifically for atomization with steam is the optimal solution – Steam Atomized Retractable Injector. This solution is preferable to feeding the neutralizer through a quill along with steam. Use of the Steam Atomized Retractable Injector ensures none of the neutralizer remains in a liquid state and is then more effective at neutralizing the HCl.
4. Fin Fan Water Wash
Problem: Poor wash water distribution and pooling on the floor of the header box
Best practice: Position the spray nozzles inside the header box itself or by using the clean-out plugs, if available, to install individual spray nozzles at pre-determined locations. Invest in a CFD study to validate performance before beginning injector design. The process gas flow rate and velocity greatly affect the performance of the spray injector, and CFD can assist in optimal spray nozzle placement.
5. Overhead Water Wash
Problem: Corrosion and salt in the overhead line and downstream equipment.
Best practice: Continuous wash water injection to prevent or remove corrosive build-up. Use of computational modeling to determine the optimal injection points, dispersion and coverage to prevent formation and salt removal. Injectors with WhirlJet® hollow cone and FullJet® full cone spray nozzles that produce small- to medium-size drops and uniform spray patterns are widely used.
6. VGO Wash Bed Spray Header
Problem: Maintain wet zones in the wash bed – dry zones can form coke and lead to higher pressure drops in the column
Best practice: Maximum Free Passage (MFP) FullJet® Full Cone spray nozzles reduce the chance to plug the spray nozzles, so nozzles run longer, as well as provide excellent coverage and larger droplet sizes at lower pressures.