Kuyaka kwa malasha m'malo opangira magetsi kumapanga zinyalala zolimba, monga phulusa la pansi ndi ntchentche, ndi mpweya wotuluka womwe umatuluka mumlengalenga. Mafakitale ambiri amafunika kuchotsa mpweya wa SOx kuchokera ku mpweya wotuluka pogwiritsa ntchito makina ochotsera mpweya wotuluka mu flue gas (FGD). Maukadaulo atatu otsogola a FGD omwe amagwiritsidwa ntchito ku US ndi kutsuka ndi madzi (85% ya malo oyika), kutsuka ndi madzi (12%), ndi jekeseni wouma wa sorbent (3%). Ma scrubbers onyowa nthawi zambiri amachotsa SOx yoposa 90%, poyerekeza ndi ma scrubbers ouma, omwe amachotsa 80%. Nkhaniyi ikupereka ukadaulo wamakono wokonzera madzi otayira omwe amapangidwa ndi madzi onyowa.Machitidwe a FGD.
Zoyambira za Wet FGD
Ukadaulo wa Wet FGD uli ndi gawo lofanana la reactor ya slurry ndi gawo lochotsa madzi lolimba. Mitundu yosiyanasiyana ya zoyamwitsa yagwiritsidwa ntchito, kuphatikizapo nsanja zopakidwa ndi zotayira, zotsukira za venturi, ndi zotsukira zopopera mu gawo la reactor. Zoyamwitsazi zimachepetsa mpweya wa acidic ndi alkaline slurry ya laimu, sodium hydroxide, kapena limestone. Pazifukwa zingapo zachuma, zotsukira zatsopano zimagwiritsa ntchito limestone slurry.
Pamene miyala yamchere imagwirizana ndi SOx m'malo ochepetsera absorber, SO2 (gawo lalikulu la SOx) imasandulika kukhala sulfite, ndipo slurry yokhala ndi calcium sulfite yambiri imapangidwa. Machitidwe akale a FGD (omwe amatchedwa kuti natural oxidation kapena inhibited oxidation systems) adapanga calcium sulfite by-product. YatsopanoMachitidwe a FGDGwiritsani ntchito chotenthetsera cha okosijeni momwe calcium sulfite slurry imasinthidwa kukhala calcium sulfate (gypsum); izi zimatchedwa limestone forced oxidation (LSFO) FGD systems.
Makina amakono a LSFO FGD amagwiritsa ntchito chopopera cha nsanja yopopera ndi chopopera cha okosijeni chomwe chili pansi (Chithunzi 1) kapena dongosolo la jet bubbler. Mu mpweya uliwonse umayamwa mu slurry ya limestone pansi pa zinthu zopanda okosijeni; slurry kenako imapita ku aerobic reactor kapena reaction zone, komwe sulfite imasinthidwa kukhala sulfate, ndipo gypsum imagwa. Nthawi yosungira madzi mu oxidation reactor ndi pafupifupi mphindi 20.
1. Spray column limestone forced oxidation (LSFO) FGD system. Mu LSFO scrubber slurry imapita ku reactor, komwe mpweya umawonjezedwa kuti upangitse oxidation ya sulfite kukhala sulfate. Oxidation iyi imawoneka kuti imasintha selenite kukhala selenate, zomwe zimapangitsa kuti chithandizo chikhale chovuta pambuyo pake. Gwero: CH2M HILL
Machitidwe amenewa nthawi zambiri amagwira ntchito ndi zinthu zolimba zopachikidwa za 14% mpaka 18%. Zinthu zolimba zopachikidwa zimakhala ndi zinthu zolimba za gypsum, phulusa louluka, ndi zinthu zopanda madzi zomwe zimayikidwa ndi miyala yamchere. Zinthu zolimba zikafika pamlingo wapamwamba, matope amatsukidwa. Machitidwe ambiri a LSFO FGD amagwiritsa ntchito njira zopatulira ndi kuchotsa madzi kuti alekanitse gypsum ndi zinthu zina zolimba ndi madzi otsukidwa (Chithunzi 2).
2. FGD purise gypsum dewatering system. Mu gypsum dewatering system yodziwika bwino, tinthu tating'onoting'ono mu purise timagawidwa m'magawo osalala komanso osalala. Tinthu tating'onoting'ono timalekanitsidwa mu overflow kuchokera ku hydroclone kuti tipange underflow yomwe imakhala ndi ma gypsum crystals akuluakulu (ogulitsidwa) omwe amatha kuchotsedwa madzi mpaka chinyezi chochepa pogwiritsa ntchito vacuum lamba dewatering system. Gwero: CH2M HILL
Makina ena a FGD amagwiritsa ntchito zokhuthala mphamvu yokoka kapena dziwe lokhazikika kuti apeze zinthu zolimba komanso zochotsa madzi, ndipo ena amagwiritsa ntchito ma centrifuges kapena makina ozungulira a vacuum drum ochotsa madzi, koma makina ambiri atsopano amagwiritsa ntchito ma hydroclones ndi ma vacuum lamba. Ena angagwiritse ntchito ma hydroclones awiri motsatizana kuti awonjezere kuchotsa zinthu zolimba mu dongosolo lochotsa madzi. Gawo la kuchuluka kwa hydroclone likhoza kubwezeretsedwa ku dongosolo la FGD kuti lichepetse kuyenda kwa madzi otayika.
Kuchotsa madzi kungayambitsidwenso ngati pali kuchuluka kwa ma chloride mu slurry ya FGD, zomwe zimafunika chifukwa cha malire omwe amayikidwa ndi kukana dzimbiri kwa zipangizo zomangira za FGD.
Makhalidwe a Madzi Otayira a FGD
Zinthu zambiri zimakhudza kapangidwe ka madzi otayira a FGD, monga kapangidwe ka malasha ndi miyala yamchere, mtundu wa scrubber, ndi njira yochotsera madzi ya gypsum yomwe imagwiritsidwa ntchito. Malasha amathandizira mpweya wa acidic - monga ma chloride, fluorides, ndi sulfate - komanso zitsulo zosasunthika, kuphatikizapo arsenic, mercury, selenium, boron, cadmium, ndi zinc. Lamestone imapereka chitsulo ndi aluminiyamu (kuchokera ku mchere wa dongo) kupita ku madzi otayira a FGD. Lamestone nthawi zambiri imaphwanyidwa mu mphero yonyowa, ndipo kukokoloka ndi dzimbiri la mipira kumapangitsa chitsulo ku matope a lamestone. Dongo nthawi zambiri limapangitsa kuti madzi otayira asalowe m'madzi otayira, zomwe ndi chimodzi mwa zifukwa zomwe madzi otayira amachotsedwa mu scrubber.
Kuchokera kwa: Thomas E. Higgins, PhD, PE; A. Thomas Sandy, PE; ndi Silas W. Givens, PE.
Email: caroline@rbsic-sisic.com
Nthawi yotumizira: Ogasiti-04-2018