Laserfiche WebLink
<br />I,'" <br />m <br />lO <br />~ <br /> <br />quality and shale oil characteristics. ~he ?ressure at which the stearn is <br /> <br />introduced depencs on the details of t~e retorting procedu~~. However, in <br /> <br />Ref. 1 a pressure of 450 psig is indicatec and we shall assume this value. As <br /> <br /> <br />discussed in Section 3.3.1, the generation of stearn at this pressure requires <br /> <br />a high qualit.y feed wa-:.er. We assume t~at ion exchange "polishing" c.emine=ali- <br /> <br />tation will be required for the 1500 gpm of water fed to ~he boilers. <br /> <br />The ~aste st:eam from the ion exchange trea~~ent is small and should be <br /> <br />no mere t~an 1 percent of the product water witn 1 ~o 2 percent total dissolved <br /> <br />solids (see Section 2.3.3). This stream may be used for low quality neecs as <br /> <br />shown in :igu~e 4.3, or if disposal is required, :his could te done by eV3pora- <br /> <br />~ion alcng wit~ t~e excess mine drainage water conc~n~rate. The acditional <br /> <br />cost is 5~f:iciently small that ~e may neglect ~t :or our purpcses he~e. <br /> <br />4.4.3 Cooling Tower 910wdown <br />As discussed earlier and shown in 2igu:e ~.3, a?proximately aso g;m ~5 <br />eva?orated in t~e cooling tower. Since tne cooling tcwer blcwdown c~~ be <br />usee ~cr disposal ar.~ other low ~ality pu~oses, it is not nece$sa~ tc go <br />to ~i;h cJcles of concentration. We have chosen abou~ 6.5 ~/cles, with t~e <br />value dictatec by the ability to ~5e ~he blowdcwn water for plar.t needs. !~ <br />t~e illustrati~e ~~ample this gives a blowdown s~~eam of abcut 160 spm. <br />Should trea~ent be required, if, for example, the plant neads prove to be <br />less, t~en disposal by evaporation is the proper wet~cd. T~~s could be <br />ac~cmpli5hed in pa~ by higher cycles of conce~t~ation =han ~sed i~ t~e <br />example ~ere (see Section 2.8.1), with the rec~cec blcwcown disposed ~y <br />forced evaporation i~ ehe same manner as the ~xcess mi~e drai~age Nater <br />ccncen~=ate. We would expect that ur.der t~e worst conditions, ~here a~l ~~e <br />blow-down hac co be disposed, t.."at by increasi.ng the cycles of conce:1t~ation <br />no more than 70 gpm would have to be evaporated in the vapor cornpress~cn syste~. <br />As discussed in Section 4.2, th1s disposal c~st would range cetween about <br />S5.85 ~~d S6.85/1000 gal (= S1910 to S2230/acre-ft) of blowdown. <br /> <br />E0 <br />