Coal Slurry Pretreatment Solution
Systems for slurry preparation, impurity removal, storage, and pumping to support stable co-firing in fluidized bed boilersCoal slurry pretreatment systems are used for coal slurry co-firing in fluidized bed boilers, where slurry agglomeration can affect combustion stability. The pretreatment process is mainly about keeping the slurry consistent and easy to pump before it goes to the boiler. Most pretreatment systems cover slurry making, impurity removal, storage, pumping, and pipeline transfer, and they also include power and control units for steady running. With these steps in place, plants can run more steadily and increase the coal slurry co-firing ratio over long operating periods.
- Hydraulic power unit (HPU) for pumping
- Conveying system
- Coal slurry is picked up from the slurry pit with a grab bucket and transferred to a receiving hopper
- From the hopper, the slurry is discharged into a slurry preparation unit, where slurry making and initial debris separation take place
- The slurry and remaining debris then pass through a vibrating screen for further separation
- The screen keeps larger debris on top for collection, and the slurry that passes through goes to a buffer hopper
- From the buffer hopper, the slurry goes through a hydraulic service valve, a twin-screw feeder, a two-cylinder plunger pump, and a high-pressure pipeline. It is then fed into the boiler through the boiler feeding system for incineration/co-firing
- The receiving hopper has a square steel structure with an outer steel frame for reinforcement. The inner surface is coated with a ceramic-filled anti-corrosion, wear-resistant lining with a thickness of at least 400 μm.
- Two sets of twin-shaft discharge screw conveyors are installed at the bottom. A rectangular discharge opening is located at the screw outlet. Positioned close to the hopper floor, the screws help break up coal slurry, feed it more evenly, and provide light mixing. They also move slurry from both sides of the hopper toward the screw inlet.
- A grate is installed at the receiving opening to stop large debris from entering the hopper.
Developed in-house for coal slurry pretreatment, this unit was designed around the way coal slurry behaves in handling. Coal slurry tends to cake, has low hardness but high stickiness, mixes easily with water, and usually does not separate into layers. To match these conditions, multiple crushing and slurrying mechanisms were tested and compared repeatedly, and the current structure was selected after optimization. The unit combines crushing, slurry making, slurry homogenizing, and debris removal. Coal slurry pretreatment systems have two functional zones: one for crushing-and-slurrying, located near the inlet and a slurry-uniforming zone closer to the outlet, without a strict boundary between them.