Crude Distillation Unit
1. Neutralizing Amine
Problem: Wasted chemical and possible corrosion on overhead piping caused by ineffective neutralizer injection.
Best practice: Use spray injectors designed to use steam as the atomizing fluid. This is preferable to feeding the neutralizer and steam through a quill. A steam atomized retractable injector ensures none of the neutralizer remains in a liquid state and provides more effective HCI neutralization.
2. Filming Corrosion Inhibitor
Problem: Creating a protective film barrier on the inside of the overhead line.
Best practice: Use WhirlJet® Hollow cone spray nozzles spraying at low flow rates and operating at lower pressures to maximize drop size and filming effectiveness. The hollow cone spray pattern effectively applies the filmer to pipe wall.
3. 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: Use spray injectors instead of quills to minimize the risk of excess free water that may not interact properly with the vapor stream and cause erosion and other corrosion issues. Instead of using flow rate and pressure drop to determine injection points, use Computational Fluid Dynamics (CFD) to validate performance prior to finalizing injector design.
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 or install individual spray nozzles at pre-determined locations using clean-out plugs. Also, use Computational Fluid Dynamics (CFD) to validate performance before beginning injector design. Spray injector performance will vary greatly depending on gas flow rate and velocity. CFD can determine 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. Injectors equipped with WhirlJet® hollow cone and FullJet® full cone spray nozzles are widely used. The nozzles produce small- to medium-sized drops and uniform coverage. Also, use CFD to determine the optimal dispersion, coverage and injector placement for corrosion prevention.
6. VGO Wash Bed Spray Header
Problem: Prevent dry zones in the wash bed that produce coke formation and result in higher pressure drops in the column.
Best practice: Maximum Free Passage (MFP) FullJet® full cone spray nozzles with wide spray angles maximize coverage and overlap to ensure uniform wetting. MFP FullJet nozzles produce large droplets at lower operating pressures than other nozzles. In addition, large flow passages prevent nozzle clogging and reduce maintenance downtime.