CONTINUOUSCOKE DRUM LEVELGAMMA-BASED CONTINUOUS LEVEL MEASUREMENT SYSTEM

Start of CycleProcess Reaches Instrumentation Measuring Top of Foam Anti-Foam Injection Switch Out

T1T2T3T4T5

T6T7T8T9T10

Foam CollapsesQuench Water Above Coke Bed Quench Water at 100%DrainingDrilling / Ready for Next Cycle

Why Use the DELAYED COKING Gamma-Based Continuous Level System?

The development of a modern continuous level system for coke drums has led to a new model for coke drum control. The system is fully configurable to meet the individual needs of our customers,and offers several benefits:

• Greater Operator Confidence by Seeing a Continuous Level• Anti-Foam Savings• Decreased Outage• Enables Minimization of Cycle Time• Early Rate Indication for Advanced Control• Quench Water Control

Principles of OPERATIONThe Ohmart/VEGA coke drum system uses a series of gamma radiation sources and FiberFlex® detectors to make the measurement. The source holders and detectors mount externally, on opposite sides of the drum. Focused radiation from the source holders passes through the drum insulation and walls to the detectors on the other side. As the process rises, it reduces the radiation at the detector which causes the detector to change outputs.

This system uses a long life Cesium 137 source, and can provide level measurement for all, or part, of the drum.

With this method, users can measure and see the parts of the process cycle including filling, foaming, anti-foam use, drum switch, foam collapse, quencing, and draining. With increased knowledge and confidence of the process level, significant through-put increases can be achieved.

The FiberFlex® has many benefits over traditional level measurement technologies. This flexible detector has no moving parts, and is able to mount externally to the vessel. For other refinery applications requiring long measurement lengths, the FiberFlex® reduces the need for multiple rigid detectors making it an ideal retrofit for older technologies.

Recognizable Benefits of the FiberFlex® on Coke Drums Include:• Eliminates Need for Cranes or Special Rigging for Mounting Detectors• Flexible Detector Has No Moving Parts and Mounts Externally• Reduces Mounting Hardware & Structural

Requirements• Eliminates the Need for Multiple Rigid Detectors• Long Detector Length Minimizes the Need for

Additional Platform Construction• Personnel Safety Enhanced by Low Weight• Reduces Shipping Costs

Other Refinery Solutions from Ohmart/VEGA:• Vaccuum Towers • Coker Conveyor Weight• Fractionization • Asphalt Bottom & Acid Unit Applications • Displacer Replacement• Separators • Tank Farm Level Measurement• Storage Vessels

APPLICATIONSVIRTUALLY UNLIMITED.

Training & SERVICEOhmart/VEGA offers several services including:

• On-site drum evaluation involving detector placement, thermal scan, platform optimization, and application engineering

• Radiation safety training for operators and maintenance personnel• Performance optimization and system documentation• Wipe test and wipe test analysis• Service, maintenance, and disposal of source material• Dedicated in-house resources and industry consultants• 24 hour emergency service phone support • Certified field staff service• Nuclear licensing assistance

CONTINUOUS GAMMA LEVEL VS. Neutron Backscatter

• No Insulation Modification Required• Can Mount to Existing Structure, Eliminating the Need for Welding• Utilizes Standard Stock Equipment• HART® Compatible With Diagnostics• Independantly Varifiable Foam Level• Direct Feedback on Effectiveness of Anti-Foam Injection• Tangent-to-Tangent Measurement Possible• Measures Across Entire Drum Versus Local Wall Area• Not Effected by Precipitation on Exterior of Drum• Actual Process Level is Independently Varifiable with Survey Meter• No Source in Electronics Housing, Providing Easy Maintenance