oilfield centrifuge

Decanter Centrifuge is one of the most common and well known equipment in drilling mud solids control project. It is often used as the fourth stage solids control equipment to remove the ultimate fine solids. To some extent, the performance of the centrifuge determines the success of the project.

2014.09.14 gn decanter centrifuge for solids control 1

GN Decanter Centrifuge for Solids Control

How to define the capacity of the horizontal sedimentation decanter centrifug

Most of the oilfield application decanter centrifuge manufacturers worldwide claim the capacity which is tested by using the water. Take the GNLW363BG small bowl centrifuge as an example, the nominal capacity is 132GPM, this capacity is for water and the actual treating capacity would be various according to the drilling mud condition or other factors. That is why when customer asks how is the capacity of the centrifuge, GN always asks the user to provide as much information of the drilling mud as possible. Usually, the solid content percentage and distribution, the mud density and viscosity is necessary required.

How to select the suitable decanter centrifuge according the purpose

The decanter centrifuge is classified as middle speed and high speed, GN team recommended to select the decanter centrifuge rotation speed according the project purpose.
a. For barite recycling, the G force 700-1000, RPM around 2000
b. For High gravity solid separation, the G force 1000-2000, RPM 2500
c. For low gravity solids separation, the G force 1800-2300, RPM 3200

How to adjust the centrifuge technical parameters for proper operation

There are some parameters of the centrifuge during operation need to be given more attention for smoothly working and specified performance result. The parameters here involved would be the bowl speed, the differential speed, the feeding flow rate and liquid discharge port plate adjustment.

  • If you want a large treating capacity, then you need raise the differential speed by raising the bowl speed.
  • If you want the liquid as clean as enough, you need raise the bowl speed, reduce the differential speed, and raise the liquid discharge plate to a high position, thus the mud would stay in the bowl for longer time, and the liquid pool would be deep. More solids would be sediment towards the bowl wall. Then liquid discharged out would have less solid particle.
  • If you want to the discharged solid material much dryer, you can raise the bowl speed, reduce the differential speed, and lower the liquid discharge part plate position. Then the liquid would be discharged quickly, and the solid may have a long distance for dewatering when getting out through the cone slope at the small end of the bowl.
  • A proper feeding flow rate is also important for well performance of the centrifuge. Always, the operator would try several times with different flow rate to choose a best one. This can be implemented only by the variable speed control pump.

GN Solids Control could provide decanter centrifuge for both fixed speed and Variable speed. For more information, please feel free to contact with us.

At the end of the Past August, GN Solids Control attended the Shanghai CIPPPE 2014 and shown there 1 unit GNLW363BG-VFD decanter Centrifuge. The visitors from oil industry paid much interest on this unit and awarded the unique design of the structure.
The model GNLW363BG is the second generation of GN decanter centrifuge. This unit is with the main drive motor and back drive motor located on the same side. Thus more space is saved to locate the fixed speed control box and for operator standing. The main motor is connected with rotation bowl directly, and the screw propeller inside the bowl is driven by the back motor through belt pulley. Comparing with GN first generation centrifuge, 1 set belt is saved.

2014.09.06 CIPPI 2014 Shanghai Oil Show

GN Decanter Centrifuge

GNLW363BG centrifuge has 2 models of fixed speed and variable frequency drive. For the common drilling fluids solids control, GN always propose to use the fixed speed model for barite recovery. The normal fixed speed of GNLW363BG is 3200 RPM, and it could be adjusted to 2600RPM by changing the belt pulley. GN could provide the belt pulley for both speeds. To change the belt pulley may take some time, and then a better way is to use the VFD model.

The GNLW363VFD is equipped with 1 unit positive pressurized design PLC control panel, which make the speed is ranging from zero to 3200RPM, the operator could adjust the speed as per the actual working and mud condition. The rotation bowl assembling unit is seen as the key part for the decanter centrifuge. Beside the material of SS2205 of the main body of the bowl, the screw is protected by bolting the tungsten carbide tiles. And to avoid the solid accumulation at the solid discharge port, the GNLW363 has the design of solids plow at the discharge port, which could effectively reduce the settlement of the solids. And at the big end of the bowl where the liquid is discharged out, the liquid discharging plates are adjustable to adjust the humidity of the discharging solid cuttings. The operator could also reduce the solids accumulation by increasing the humidity.

Now, the GN third generation decanter centrifuge is under fabrication processing, this generation would much better solve the problem for solids accumulation and extent the critical part life time. GN sincerely appreciate the support and trust coming from the customers.