Blue Flower

GNLW452S decanter centrifuge was ready for delivery to Kazakhstan. This is a middle speed decanter centrifuge which operates 815 G’s at bowl speed of 1800RPM with 2-5 micron solids removed.

Decanter Centrifuge to Kazakhstan 001
Driven by one 45kw (60hp) electric motor, the normal operating flow capacity of this unit is 176GPM (40M3/h) and can reach maximum to 250GPM (57m3/h). The solids bowl diameter is 450mm (17.7inch) and bowl length 1100mm (43.3inch).

Decanter Centrifuge to Kazakhstan 002
In Kazakhstan, GN has gained the good fame. Beside the decanter centrifuge unit, GN also have HDD Drilling Mud Recycling Unit Working in Kazakhstan.

In the classic weighted mud application the solids discharge (containing the majority of the weighting material) is returned to the mud system. The liquid effluent (containing the majority of the colloidal size solids) is discarded. As part of a“closed loop”, larger high capacity (75–250 GPM) decanting centrifuges (and sometimes standard centrifuges) are used to maximize fine solids removal. The coarser solids fraction is discarded in dry form, while the liquid and colloidal solids fraction is returned to the mud system.

decanting centrifuge

Decanting centrifuges are becoming more popular for processing unweighted oil mud, especially if
1) the mud has been brought in from another location and may contain a large amount of fine drilled solids,
2) slow, hard drilling with a gradual buildup of ultra-fine solids is anticipated or
3) the liquid mud phase is valuable.
GN offers Decanting Centrifuge for unweighted mud applications.

Decanting centrifuges for oilfield applications were first introduced in the early 1950s. These early units were adapted from existing industrial decanting centrifuges. In the mid-1960s, a perorated rotor type machine was developed which does not perform like a pure decanter. Commonly called “barite recovery” centrifuges, these early designs were limited in capacity and application.

Today, the decanting centrifuge is even more important part of solids control. In addition, the increased use of low-solids mud and environmental dewatering applications require higher process volumes, greater clarification and solids capacity, and additional fine solids removal. Equipment selection is decided by site specific requirements. Proper system selection is the first step to effective solids control.

GN decanting centrifuge is purpose-built for drilling mud solids control in oilfield applications.

Decanting centrifuge is an import ant piece of equipment in mud solids control. Because of the environment regulation and high cost of drilling waste disposal, many CBM and HDD operator now prefers decanting centrifuges in their mud recycling system.


Also, as fluid costs increase, centrifuge use is highly recommended for reducing costs. The Australian client requires two set of GNLW363G decanting centrifuge to remove the supper fine solids to control the drilling mud density for reuse.

You can learn more about this Water Based Mud (WBM) Recovery System at GN solids news center.

According to Stokes Law, particle setting velocity is proportional to G-force. Since G-force increases with the square of bowl RPM, it is an important parameter of decanting centrifuge performance. G-force also increases linearly with bowl diameter. Figure 1 shows how solids removal efficiency improves with increasing G-force. For a given particle size and fluid properties, there is a minimum G-force necessary to invoke settling. Although high G-force is desirable, the cost is proportional to the cube of the bowl rpm and there are similar economic limitations on bowl diameter as well. Thus, the required G- force must be obtained from a practical combination of speed and diameter. Most oilfield decanting centrifuges have bowl dimensions from 14 to 28 inches in diameter and lengths from 30 to 55 in. Rotational speeds range from 1000 rpm to 4000 rpm, depending on the application. The more expensive, high “G” machines can provide up to 3,000 G’s.

Effect of G-Force on Separation (Higher G's Improve Separation Performance)



Note: however, that increasing G-force eventually reduces solids conveyance capacity due to torque limitations. As G-force increases, more solids are settled in the bowl and they adhere more tightly. More conveyor or torque is required to move the solids out. Once the torque limitations of the machine are reached, conveyance ceases.
G-Force for a Decanting centrifuges:
G’s = RPM2 x .0000142 x Diameter of Bowl (in inches)

High G-force decanting centrifuges are available from GN Solids Control.

The decanter centrifuge is used in weighted mud applications to recover valuable weighting material from mud which must be discharged due to unacceptable colloidal solids content. The decanter centrifuge settles out barite and coarse drilled solids which are returned to the active mud system to maintain density. The relatively clean centrate containing liquid and colloidal solids is discarded. These colloidal solids cause many drilling fluid problems, such as high surge/swab pressures and ECD, differential sticking and high chemical costs. Usually the value of the weighting agent in these mud systems makes it economic to recover the weighting agent from the whole mud before it is discarded.Ideally, the barite recovery process should remove only colloidal solids without losing the larger particle sizes used as weighting material.

Discarding potentially reusable barite increases barite use and drilling fluid cost. Barite losses can be reduced when the centrifuge makes the maximum liquid/solids separation. As discussed in the previous section, this means operating the decanter centrifuge at high G-force.