Tunnel Boring Machine (TBM) also known as a "mole", is a machine used to construct the tunnel by excavating material in front of the TBM,behind which concrete segments are installed. Slurry Separation plant is used to separate the excavated material from the bentonite slurry. Slurry separation plant is the central facility where the bentonite slurry coming from the TBM is treated and recycled. It is then fed back to the header tank through the slurry circuit to TBM. The configuration of the slurry separation plant have to be tailored to both the actual volumes generated and also the types of soil being excavated. The prevailing ground conditions presented an enormous challenge not only for the tunnelling operations but also for slurry separation.
GN Solids Control is leading Chinese Solids Control equipments manufacturer.TBM Slurry Separation Plant is one of their main products, except for the Solids Control System used for oil/gas drilling. Take one GN 240m3/h Slurry Separation plant as a example. I will show you the compoents of the plant and how does the slurry separation plant work.
Equipments list of GN 240m3/h Slurry Separation plant:
1) 2 units GNZS703 shale shaker
2) 1 Unit GNZJ703-2S16N Mud Cleaner
3) 2 SB8x6-13 centrifugal pump for feeding desander and desilter.
4) 2 Mud agitators
5) 1 unit Jet Mud Mixer
6) Mud tanks
Working procedures of GN 240m3/h Slurry Separation plant:
1. The raw slurry (After Drilling) feed to Slurry separation system by a slurry pump from TBM.
2. In the first phase the slurry passes over scalping 2xGNZS703 Shale Shakers to remove larger particles. es. Solids Size≥0.8mm will be removed from the fluids.
The 2xGNZS703 Shale Shaker is fixed with 20 mesh shaker screens.
3. The slurry with solids size≤0.8mm, with the above particles removed drops into an isolated section of the tank(1rst Compartment of 1# Recycling Tank) where it is picked up by the 1rst SB8x6-13 centrifugal pump.
4. This pump moves the slurry to the second phase, which is the De-sanding phase.
5. Here the slurry is pumped through the de-sanding Hydro-cyclones(2x10 inch desander cones which is mounted over GNZJ703 Mud Cleaner), which removes the solids above the 75 micron size.
6. The overflow from these hydro-cyclones drops into a second isolated tank section((2nd Compartment of 1# Recycling Tank), while the underflow is deposited onto vibrating screens for drying of the solids.
7. The slurry, which now has solids removed above 75 microns is picked up from this tank section((2nd Compartment of 1# Recycling Tank) by a second SB8x6-13 centrifugal pump and pumped through a bank of de-silting hydro-cyclones(16x4 inch de-silter cones which is mounted over GNZJ703 Mud Cleaner) to remove the solids passed by the de-sanding hydro-cyclones. This phase removes solids down to the 25 micron size. Again the overflow from the de-silting hydro cyclones drops into the third tank section(1st Compartment of 2# Mixing Tank), while the under flow is deposited onto vibrating screens for drying.
8. The now “cleaned” fluid is in the the third tank section(1st Compartment of 2# Mixing Tank).
9. The Separated skid SLH150-50 Jet Mud Mixer is connected by pipe with 2# Mud Mixing Tank.Which can be used to adding chemicals, bentonite and preparing new slurry for TBM.
For more information about TBM slurry separation plant, Please feel free to contact with GN Solids Control. GN enginners will give you the best solutions for your project.