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<br />,..~ <br />~ 3. <br />:.Jl 3.1 <br />CO <br /> <br />WASTEWATER STREA.'lS IN THE SURFACE RETORTING OF OIL SHAll <br /> <br />Water Management <br />In this section we will discuss the wastewater streams associated with <br /> <br />the mining and surface retorting of oil shale and the methods of treating and <br />managing these waters. The data that will be presented was derived primarily <br />from three oil shale retorting processes; Parano Direct and Indirect heated <br />retorts 1 and Tasca II2, and combinations of each3. The water management <br />schemes for these processes are representacive of the wa~er management schemes <br />of the various other surface retorting technologies a The role that water <br />plays in the production of synthetic crude from oil shale is presented in <br />Reference 4, ~ogether with a desc=iption of various retorting processes a~c <br />calculations of the water requirements for large oil shale mine-plant complexes. <br />References 5-8 also present the water related i~pacts of shale oil conversion. <br />In an integrated oil shale mine-plar.t complex, there is a net consumption <br />of water. All surface processing operations involve mining, crushing, r~tcr~ing <br />and upgrading to produce a synthetic crude oil for refining. Water is required <br />:or dust centro 1 in ~~e mine, for crushing and :cr other dust cont=ol opera~ions <br />in transpc=~ing the crushed shale to the retort. When shale is retorted, <br />lar9~ quantities of water are evolved, partly due to the surface moisture of <br />the shale, partly from ~~e thermal decomposition of the ca~bonate materials <br />and, in direct retorting, ?artly from the water produced in cOmCus~ion~ <br />However, in indirect re~orting, the wat~r i~ the combuscion produc~ ~s generally <br />lost ~p the stack. Some processes require large amounts of cooling in retor~inq, <br />while others require little or no cooling, ~~e actual amount dependi~g on how <br />the retor~ operates~ Cooling water is required, however, in di5sipa~ing waste <br />heat that has been generated in the plant. Steam will be consumed for proc~ss <br />cooling and in distillation or stripping columns. Finally, water may be <br />required for the disposal and revegetation of the spent shale pilas. <br />From t~e point of view of wate: mana9a~entr t~e type of retort and the <br />method of disposal of the spent shale are quite important. The Tasca II and <br /> <br />paraha retar~ing processes represent two dif:erent limits with respect to water <br />trea~en~ and water management schemes and ~~e quanti~y of water consumed in <br />disposing of and revegetating the spent shale. <br />The processed shale from the Tasca II retort is a fine black sandy ~ate~ial <br />wi~h about 60 percent of the particles passing through a 200 mesh screen <br /> <br />53 <br />