TBM Pipe Jacking engineering are widely used in urban construction, normally it will face a problem of working area limit, working noise limit and environmental protection limit. GN TBM Slurry Separation Plant is designed to meet all of the requirements mentioned, the features of GN TBM slurry separation plant including compact design, high treating efficiency, better treatment result, different treating capacity, easy movement, convenient disassembly for different requirement. Except for small desander unit of TBM slurry separation plant–GNMS-500D & GNMS-1000D, we also have below models of middle TBM slurry separation plant and large TBM slurry separation plant:
Take GNTBM-240 (240m3/h) for example, it consists of 1 unit of desander mud cleaner with double deck bottom shaker and 2 ea desander cone, 1 unit of desilter mud cleaner with double deck bottom shaker and 12ea desilter cone, 2 units of desander desilter feeding pump, mud tank with lifting frame for convenient transportation. During transportation, the top layer desilter mud cleaner will be disassembly to meet the road transportation height limit. The whole system without disassembly can be shipped by bulk cargo vessel. The complete system are controlled together, it is installed on the position where is convenient for operation. Both of the desander cleaner and desilter cleaner discharge the separated solids from one end of the TBM slurry separation plant. The total screen area is 5.33m2. The working process is as below: The TBM slurry is fed to desander cleaner and desilter cleaner scalping screen to separate coarse solids, the slurry dropped into the fluids catching tank, the desander feeding pump transfer the slurry to desander cone to separate sand/silt, the solids dropped on the fine shaker screen to make it drier. The fluids flow to catching tank and the desilter feeding pump transfer the fluids to desilter cone, the solids on the top fine screen to dewater the solids.
WBM waste treatment system technical specification: 1) High G drying shaker to separate coarse solids from the drilling waste, 2) VFD decanter centrifuge to separate fine solids from the drilling fluids, the chemical dosing system add chemicals into the waste water to improve the separation performance and efficiency.
The working principal of the decanter centrifuge to separate fine solids from the fluids is as below: The bowl and the screw ( inside the bowl) rotate by the same direction with a differential speed. the waste water is fed to the screw shaft by the centrifuge feeding pump, under the centrifugal force working, the solids desposited to the bowl wall and the solids is continuously pushed to the cone section of the centrifuge bowl and discharged to solids distribution port. Because of the gravity difference, the fluids overflows to the liquid distribution port which is in big end of the bowl. The straight bowl material is made of duplex stainless steel 2205 or 2304 by centrifugal casting, as clarification phase, the cone section is made of stainless steel 316L, which is as extrusion drying area. To adjust the differential speed by VFD control panel is very important operation for VFD decanter centrifuge, it will influence the decanter centrifuge separation performance a lot, the user should read the operation manual carefully and to be trained to input correct differential speed by the touch screen and controlled by PLC smart control.
The flow rate can be controlled by adjust the frequency of pump motor. When start the decanter centrifuge, the flow rate should be set properly in case that high flow rate lead the too high electricity currency which will burn the motor. After treated by decanter centrifuge, most of the ultra fine solids up to 1 microns will be separated out and get relative pure water.
GN solids control shipped several units of vertical cuttings dryer and decanter centrifuge to Russia with customized painting color. As the expert of solids control & drilling waste management in China, we have exported a lot of vertical cuttings dryer and decanter centrifuges to Russia area.
The vertical cuttings dryer and decanter centrifuge is the major equipment of zero discharge system for oil based drilling cuttings treatment. The working process is as below: The screw conveyor collect the oil based drilling cuttings from the shale shaker of solids control system and discharged to 2# screw conveyor, the 2# screw conveyor is installed slantly and transfer to vertical cuttings dryer top open feeding port. The vertical cuttings dryer dry the drilled solids from oil based cuttings by centrifugal force. The screen basket traps the fluids and accelebrates them up 900rpm and G force is up to 420G. The fluids is discharged from the liquid discharged port and flow to intermediate tank, the feed pump transfer the liquids to decanter centrifuge to separate fine solids, the cut point is 2~5 microns. The clean fluids is recovered by the catch tank or connect the pipeline back to solids control system for reuse.
VFD decanter centrifuge should be applied for drilling waste management system, which with 3 motor frequency VFD, main motor, back drive motor, pump motor. We use ABB brand inverter for easy outsourcing when need to be replaced, all the other electrical components are also with ABB, Siemens, Schneider with good quality. Our VFD control panel is positive pressurized VFD control panel with PLC smart control and HMI interface. The screw pump as centrifuge feeding pump flow rate can be adjusted by changing the motor speed. We also produce complete drilling waste management system with our standard compact design, for cold area, we can install the system inside the container.
Recently 2 sets of oil based drilling cuttings treatment system are ready for shipment to Russia. Same with previous order, the vertical cuttings dryer and decanter centrifuges are installed in the container with insulation layer to keep the equipments warm in cold weather in China. The technical configuration is as below:
1) Vertical cuttings dryer for oil based drilling cuttings treatment, the oil on the discharged cuttings is below 5%, the client can disposal the solids directly or send to TDU unit according to the environmental protection regulations in their country. The treated fluids will flow to the intermediate tank, the feeding pump of decanter centrifuge will feed the fluids to decanter centrifuge to separate the fine solids. The vertical cutting dryer is installed on the frame inside the container.
2) The waste decanter centrifuge will separate the solids cut point 2~5 microns from the fluids, the discharged fluids can be reused by drilling and prepare for new fluids. 3) Positive Displacement pump is as the feeding pump of decanter centrifuge and installed in the container. 4) The 40ft standard container with windows, doors and top open hole for easy replacement of the screen basket which is wear parts of the vertical cuttings dryer. The insulation layer attached with container is to keep the equipments working well in cold weather in Winter, it is special design for Russia clients.
Why use GN vertical cuttings dryer system? As per the feedback from our client who has used GN drilling waste managements system, the vertical cuttings dryer system can reduce the drilling waste volume effectively, and the recovered drilling fluids can be reused, the client can save cost and time to transfer the drilling cuttings to third party facility for treatment. And more and more countries forbid to dig waste pit at rig site for environmental protection.
2 more construction slurry cleaning system for vacuum tanker vehicle is ready for shipment to USA, this is the client’s repeat order. After use the previous 2 system at their work site successfully, they repeat the order for another 4 units, this is part of their new order. They have given some good suggestions to improve the system efficiency and to be user friendly. The basic working principal is as below:
The slurry collection hopper collect the construction slurry from vacuum tanker vehicle, this is special designed slurry collection hopper — a large open top hopper with 3-side weir surrounded, 1 side is low weir for slurry feeding from the vacuum tanker vehicle. The coarse solids separation shale shaker is sitting on it, the separated coarse solids/stones are collected by cuttings box, the clean slurry is dropped into the collection hopper and feed to the fine solids separation shale shaker by the submersible slurry pump. The fine mesh screen is installed on the fine solids separation shale shaker with composite material frame shaker screens for longer working life. GN can produce composite material shaker screens comply with API RP13C from API 20 to API 325. The slurry discharged shale shaker is feed to mud cleaner with desilter cone, the separation cut point is 25 microns by centrifugal pump, the discharged solids is drying by the bottom shaker screens.
The clean slurry is feed to high speed decanter centrifuge by working with dewatering unit by the screw pump, we have different size decanter centrifuge with different treating capacity for option, the bowl size with 9 inch, 14 inch, 18 inch, 22 inch, 30 inch. To get much pure water, sometimes chemical should be add to improve the separation efficiency. If you have similar project, welcome to contact with GN sales engineer.