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Closed loop automation control of decanter centrifuge

on . Posted in News

Decanter centrifuge plays a crucial and indispensable role in the solids control of oil and gas drilling.

As more and more drilling activities be implemented in low permeability and unconventional reserves, drilling is becoming more demanding on the performance of decanter centrifuge, that is, they need to be more intelligent.

On the other hand, the ever-increasing labor cost forces drilling operators to seek more controlled way of drilling operation. Automation is a promising solution for such initiative.

Traditional decanter centrifuge uses fixed speed electrical motors to provide power for the centrifuge. Differential speed is provided by star-transmission.

This presents a big potential danger to the operation of the decanter centrifuge. For instance, if, for any reason, the rotor motor stops operation while the main motor is still rotating at 3000 RPM, the whole centrifuge will soon be filled up with solids and the main motor will be tripped due to over load. This will create a big problem for the operation, and it usually takes days to clean out the consolidated solids inside the barrel. This is absolutely not acceptable in a mission-critical environment.

In addition to this risk, fixed speed decanter centrifuge also faces the challenge of changing work load. In a typical field operation, the incoming material feed changes tremendously. Sometimes the flowing-in fluid is mainly water, with little solids in it. Sometimes the incoming stream has very high solids concentration. These are the two extreme feed conditions for the centrifuge to handle, which impose great challenges for the machine as they require absolutely different differential speed.

This kind of fixed speed decanter centrifuge also lacks other conveniences such as making minus changes on the differential speed so as to perform field cleaning up of the decanter centrifuge.

More advanced decanter centrifuge such as those manufactured by GN Solids Control uses variable frequency drive to provide the differential speed necessary for the discharge of separated solids. This kind of decanter centrifuge provides outstanding performance quality over fixed speed centrifuges.

With the addition of automation technique, the following feature can be achieved:

  • Automatically changing the differential speed with changes in solids concentration of the incoming flow;
  • Interlock of the two motors if either one fails, and shut off the incoming valve;
  • Lowering, or stopping the system if there is no fluid coming in for certain amount of time;
  • Manually changing the differential speed for system cleanup
  • Automatic monitoring and alarming of bearing overheating, and shut off the valve(s) for incoming fluids, and take automatic measures (if available) to stop the deterioration of the situation;
  • Communicate with other equipment in the work stream, to establish an integral material handling system, to optimize the performance of the whole system at designated targets
  • And the inclusion of automation technology may eventually evolve into a AI system, with self-learning and self-decision-making system.

Advancement in transducer will be the flash to trigger this revolution.