Centrifuging Hydrocyclone Underflow

Published on January 12 2015 by gnsolidsamerica

When liquid discharge should be strictly controlled because of high mud cost, high liquid disposal cost or limited reserve pit capacity, the centrifuge should process the underflow from the desilter cones. Within this disadvantage fulguration, the hydrocyclones are utilized to concentrate solids towards the centrifuge which then separates the drill cuttings in the free liquid and colloidal solids. System performance could be enhanced by opening the cone apexes to discharge more liquid. This enhances the separation efficiency from the cones and creates less viscous slurry in the underflow. Figure 5 gives a good example of how centrifuging desilter underflow becomes economic with growing mud cost and desilter underflow rates. Enough centrifuge capacity should be open to process a little more compared to cone underflow rate. Additional make-up volume ought to be provided from the active system downstream from the hydrocyclone feed.

Since the hydrocyclone underflow should be segregated in the active system, another centrifuge feed compartment is needed. Figure 6 and seven demonstrates two designs for that centrifuge feed compartment. The compartment ought to be small (<50 bbl) to prevent solids settling. Both everywhere equalization ought to be provided. The reduced equalizer supplies make-up volume in the active system throughout normal processing. A valve (normally open) ought to be placed on the reduced equalizer. This valve might be accustomed to make sure that the centrifuge feed rate surpasses the cone underflow rate. When the centrifuge will be utilized in weighted mud to process the centrate from the barite recovery centrifuge, the valve ought to be closed to isolate the feed compartment. Our prime equalizer is provided to prevent accidental overflow.

The centrifuge can be used in weighted mud programs to recuperate valuable weighting material from mud which should be released because of unacceptable colloidal solids content. The centrifuge forms out barite and coarse drilled solids that are came back towards the active mud system to maintain density. The relatively clean centrate that contains liquid and colloidal solids is thrown away. These colloidal solids cause many drilling fluid problems, for example high surge/swab demands and ECD, different sticking and chemical costs. Usually the need for the weighting agent in these mud systems causes it to be economic to recuperate the weighting agent from the entire mud prior to it being thrown away.

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