Research On Pneumatic Conveying Technology For Wet Drilling Cuttings

Without harmless treatment, cuttings produced during the drilling process will bringgreat pollution to the environment. Because of the poor liquidity of cuttings, it is hard totransport them among treatment equipments. Pneumatic conveying technology for wetcuttings can make it possible to transport them flexibly and improve the environmentalproperty of equipment.It is found that pneumatic conveying system designed according to the classical theory isnot fitted to the conveyance of wet particle. Wet particles stop moving and stay around theinlet, inside the pipe and the elbows. The use of dispersing machine, increasing of conveyingvelocity, and better elbow with larger R/D has made the wet particle pneumatic conveyingpossible. Each critical conveying velocity under different particles or elbows was achievedthrough experiments, and with R/D>10elbow, wet particle can be conveyed under100m/s airvelocity while liquid percent is less than15. Influence factors affecting the particle conveyingwere weighed by orthogonal experiment, and the significance order is liquid percentage,liquid viscosity, particle size, R/D. The pressure drop across horizontal pipe, vertical pipe andelboews was measured for both dry and wet particles. Furthermore, the empirical formulacalculating pressure drop was obtained, available for engineering design.Pneumatic conveying under different conditions was simulated using FLUENT software.Different suspended velocities and mimium conveying velocities under different conditionsare obtained, and it is found that the elbow in the pipe system affects the particle movementgreatly. Compared with experiments, simulations are accurate. The particle volume fractionachieved shows that different particles cause different wearing areas. Through the simulation of air-liquid-solid system, wet particle conveying was obtained. It is found that the existenceof liquid make the particle attach to the pipe wall. The result is really in coincidence with theexperimental phenomenon. The simulation of various particles with different sizes shows thatthe particles will affect each other, under the condition that different particles possess nearlymass. The conveying property of bigger size particle can be improved by smaller size particle,while the smallest size particle has almost no effect on the big size particle.