GN Solids America has designed a new slurry separation plant for tunnel boring machine (TBM) drilling mud cleaning.

The plant allows drilling contractors to get clean water from the TBM slurry and reuse it in the TBM project. This eliminates the need for waste disposal and saves money.

Primary Slurry Separation Plant

The primary separation plant is for the separation of solids of up to 45 microns. It uses double deck shale shakers, desander cleaner, mud tanks with attachments, centrifugal pumps and a mud agitator.

Dirty slurry comes from the TBM and feeds to the GNZS706E-HB shale shaker top layer screen to separate solids bigger than 2 millimeters. Then fluids go through the top layer screen to the bottom layer screen to separate solids of 400 microns.

Later, a centrifugal pump pushes fluids from the mud tank first compartment to the 3-inch by 10-inch desander cones on the GNZJ703E-3S shale shaker. This is the third phase separation for solids bigger than 45 microns. After the desander, the fluids go to the second compartment of the mud tank.

Slurry Dewatering Centrifuge Separation

The slurry dewatering centrifuge separation unit is a 40-foot containerized system for separation of fine solids from the drilling fluids. It consists of a big bowl, big volume decanter centrifuge and a double chamber flocculation unit.

The decanter centrifuge has a PLC control system with touch screen to control bowl speed, differential speed, feeding pump speed and flow. A password is required to operate the touch screen and a locking system is provided to operate the touch screen with keys.

Flow meters of centrifuge feeding line and flocculent feeding line send a signal to the PLC control system to protect the pump from dry suction.

The double chamber flocculation unit mixes chemicals for the flocculation of the drilling mud taken from the second compartment. Then the slurry and polymer are mixed and fed to the big bowl, big volume decanter centrifuge.

The VFD decanter centrifuge has g-force up to 2000 g, which separates the fine solids in the drilling mud and discharges clean water for reuse in the TBM project.

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