Berthold's solution for fluid catalytic cracking (FCC) processes

Graphic of Fluid catalytic cracking unit FCC process

Measuring the level of catalyst fines in cyclone separators

Catalyst fines have to be removed from the regenerator flue gas to fulfill regulatory requirements and to protect downstream equipment. Thus cyclonic separators are used to filter out the remaining catalyst fines. The solid particles settle down at the bottom of the separator, where their level is  controlled by radiometric level systems from Berthold. The non-contacting technology is ideally suited for this kind of application since dust
and temperature have no impact on the measurement performance.

Measuring the level in catalyst regenerators

Proper level control in the regenerator of a FCC unit is critical for maintaining optimal operation and protecting equipment. In the regenerator, spent catalyst from the reactor is regeneratedby burning off the coke deposits. The level of catalyst needs to be maintained above the dip legs of the cyclone separators for effective separation of the catalyst particles from the flue gas. This helps to ensure the efficiency of the regeneration process and to prevent the catalyst from being carried out with the flue gas, which can lead to erosion or damage to downstream equipment.
Radiometric level systems are used in the regenerator to maintain the appropriate catalyst level. This non-contacting, non-invasive technology provides several advantages for this unit such as accurate catalyst level control insensitive to process conditions.

Customer benefits

  • Improved catalyst removal
  • Improved safety and effectiveness of operation
  • Ideal utilitzation of vessel capacity
  • Improved process efficiency and output quality of the regenerated catalyst
  • Reduce or prevent catalyst in the gas


  • Reliable control of catalyst level and feed
  • No fouling or clogging
  • Installed at the bottom conical part
  • Non-contact, non-intrusive technology
  • Providing bed density profile and total catalyst level
  • Immune to interfering radiation with built in XIP feature, or continue level measurements during weld inspections with RID model
  • No re-calibrations required

Article "Made to measure"

Catalytic cracking, especially fluid catalytic cracking (FCC), is one of the most important conversion processes used in the refineries. To ensure a control of the entire cracking process, level measurements are essential. But the extreme process conditions of a fluid catalytic cracking unit pose some challenges for the measurement technology. The article “Made to measure” (published in the journal Hydrocarbon Engineering April 2020) explains why the use of radiometric measurement systems can help to optimize level control in FCCUs and how Berthold systems can help you to control your process more reliably to ensure safe operation while increasing efficiency.

 Download your copy

SIL certified option

The SENSseries LB 480 detectors offer versions that are certified for use in SIL2 applications. SIL3 is achieved by adding an identical redundant SIL2 detector using the same source for homogenous redundancy. The certificate covers all measurement applications, from high level or low level alarms to continuous level. Thus the safe measurement of critical processes is guaranteed.

More about SIL


Long-term stability

A reliable measurement, requiring no recalibration, is vital for the operation of the FCC, and is our highest priority. Berthold’s detectors offer stability in the face of changes in ambient temperature. Even drastic temperature shifts, e.g. from winter to summer do not cause measurement drift. Our patented method for detector stabilization compensates for temperature changes and aging.

Detector Stability

Radiation Interference Protection (XIP)

With this function, weld tests no longer cause sudden fluctuations in the measured value. When weld tests are detected, the measured value is frozen until the external radiation event ends. A digital output can be set to signal the detection of interfering radiation. 
All of our level measurement detectors are equipped with XIP.

More about XIP


Further applications

Vessels that use radiometric devices in the FCC besides cyclone separators are electrostatic precipitation hoppers, reactors and distillation tower bottom levels. The radiometeric level measurement on the fractionator tower bottom, unlike differential pressure, is unaffected by the changing percentage of catalyst fines. This increases the reliability of the level potentially preventing tray damage if level gets too high, or pump damage if level gets too low. Level and density measurements of the fluidized bed in the standpipe is also a frequently required measurement task.


Measurement solutions for the refining industry Industry brochure

English | PDF | 2.6 MB

Made to measure Publication

English | PDF | 6.8 MB