The Experimental Investigation Of Drying Drilling Waste Slurries By Fluidized Bed Of Inert Particles

The drilling waste mud is mainly compose of bentonite, clay, rock debris, bariteand many kinds of few chemical ingredients.There are many characteristics about it,such as the high COD_Cr content, the tiny pellet, the narrow gradation, the bigviscosity, the high moisture content,not easy dehydrates, strongly alkaline.It is thetypical viscous suspension colloid system.In order to prevent the drilling waste mudpolluting the earth surfaceand water and restores the cultivation after the wellcompletion,we must harmless disposal it. At present the domestic and foreigndisposal method is very much, such as drying,burning down, centrifugal separating,the solidification, the systembrick and so on.The method that the powder is made bydrying and burning down to recycle using is favour by more and more developedcountry. At the scene drying the drilling waste mud may both solve theenvironmental pollution problem,and recycle using the high-density material indrilling mud to reduce the well drilling cost. The empirical data of the rheologicalproperty,the filters loses, the suppression, the lubricating ability showed that drillingmud of the high-density material by the drying product is satisfiedly to drilling fluids.The method that well drillings waste mud is dried is mainly the fluid bed burns downand spray drying in the domestic and foreign. But the consumes of fuels is massivemoreover it is uneconomical.In this article it is used to dry well drilling waste mudby diesel engine waste gas,and dry, grinds by the fluid bed of inert particles directlyobtains the powder product. Experimental result: (1) it is used to spray feed because organic content is high, theviscosity is high in waste mud. Otherwise it can cause to be able the normaloperation because the inert particles coheres to the group. (2) Merit of the fluidizedbed with inert particle are that the volume heat transfer coefficient is high, the dryability is big and the drying time is short, the volume heat transfer coefficient mayachieve 3～6kw·m^-3·K^-1, the thermal efficiency may achieve 40～60%. (3) It is similarthat effect of maximum material rate on the wind velocity,enters wind temperature,the waste content, the bed altitude and height of the spray nozzle at the experimentand the mathematical model. Therefore this model providesthe basis to engineeringdesign in fluid bed of inert particle.(4)Because the equipment volumes of the fluidbed of inert particle is small and its structure is simple,it is used in the land and thesea platform. (5) The temperature of the organic matter decomposesed andvolatilization is about 350 to 400 degree celsius.The particle size distribution of dryproducts was analyzed by laser particle size analyzer,the range of the particlediameter was narrow with average diameter of 12μm.The density of the dry productsis 3.2 g·cm^-3.It is used to increase the density of the drilling slurries.The lixiviatedvalue of COD_Cr of dry products was adequately lower than that of drilling wasteslurries.Drying medium is low temperature industry waste gas in the experiment.Thelow-grade industry waste gas is direct discharged to the atmosphere in the actualproduction, the environment is polluted. The energy of the industry waste gas is usedto dry the drilling waste mud in the experiment. It is better realizated that the energyis conservation and the pollution is reduced.