The delayed Coker is the only semi-continuous batch process in the refinery, which means that the feed is continuously switched between two drums in a time-based cycle. The fresh feed, usually from the vacuum tower bottoms, is fed to the bottom of the Coker fractionation tower to help pre-heat the feed and mixed with the bottom hydrocarbons. This mixture is then passed to the heater to apply the energy required to thermally crack the large hydrocarbon chains. After that the heated resid is pumped to large drums to allow for the cracking and expansion of the fluids, whereby the lighter cracked hydrocarbons are taken off the top of the drums to the fractionation tower. As the heavy hydrocarbons are cracked, the resulting hydrocarbons are then converted into a vapor due to the high temperature. As the vapors escape the viscous liquid, they tend to create a foam layer. This foam layer can vary depending on many parameters such as operating temperature, pressure of the drum, type of crude, charging rate etc. A foam over in a delayed Coker unit can be a costly event, not only causing loss of production but also requiring a lot of manual labor to clean coke out of the overhead lines and fractionation tower. In order to increase throughput of the unit, one of the most important objectives is to safely and reliably fill the drum higher, however, to achieve this, one must have a reliable measurement method for the foam front in the drums. Due to the conditions in the coke drum, a level measurement is a very challenging task. Where other measuring technologies tend to fail or end up being extremely unreliable, Berthold‘s radiometric level technology is ideal for monitoring the coke level due to its non-intrusive nature. Since large temperature variations through the whole operational cycle of a coke drum are a known issue to the operators, our patented automatic stabilization technology based on cosmic radiation has proven to be the most important feature to guarantee a stable and reliable level measurement without the need for recalibration. Separate level alarms ensure additional process safety. The same applies for the fractionator. Our level gauges are used to monitor the bottom liquid level – an important parameter for the efficient control of the complete coking cycle. A big advantage is that measurement is unaffected by surface turbulences, product falling from the trays, different product densities, or scaling/coking.
COKE DRUM System
- Safe and reliable operation
- Increased throughput
- Improved utilization of drum capacity
- Efficient use of anti-foam agent
- Non-contacting, non-intrusive level measurement
- Use of 8 m long TowerSENS detectors (covering up to 32 m in cascaded mode)
- Highest sensitivity due to solid scintillators leading to significantly lower source activities
- High repeatability and long-term stability
- SIL certification available
- Minimizes NDT interference with internal proprietary algorithms
- Gas property compensation (GPC) – compensation of gas density variations for the continuous level measurement
At Stuart Hunt we know our business! Using our varied product portfolio, our specialized knowledge and extensive experience, we develop solutions together with our customers in a wide variety of industries and applications. Our partnership with Berthold Technologies allows us to offer a true “cradle to grave” solution for all your nuclear needs. Berthold’s specialization in radiometric process measurements for over 70 years gives our clients the peace of mind that they have always found with us.
Contact us for additional information.
1-800-661-4591 ext: 320