ISPITIVANJE MOGUĆNOSTI ISTOVREMENE EKSPLOATACIJE UGLJA I ULJNIH ŠKRILJACA U ALEKSINAČKOM BASENU

7/31/2019 ISPITIVANJE MOGUNOSTI ISTOVREMENE EKSPLOATACIJE UGLJA I ULJNIH KRILJACA U ALEKSINAKOM BASENU

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Broj 1,2010. RUDARSKI RADOVI37

KOMITET ZA PODZEMNU EKSPLOATACIJU YU ISSN: 1451-0162

MINERALNIH SIROVINA UDK: 622

UDK: 622.337:622.33(045)=861

Dejan Sokolovi*, edomir Belji*, Duan Gagi**

ISPITIVANJE MOGUNOSTI ISTOVREMENE EKSPLOATACIJEUGLJA I ULJNIH KRILJACA U ALEKSINAKOM BASENU

Izvod

Pratei nastojanja i aktivnosti u drugim zemljama, koje poseduju uljne kriljce, vidimo da se na

ovaj energetski potencijal rauna i intenzivno radi na osvajanju ekonomskih tehnologija njihove

eksploatacije i prerade, u cilju dobijanja tenih i gasovitih ugljovodonika i drugih vrednih

proizvoda.

Obim i struktura energetskih resursa i energenata u Srbiji je u nezavidnoj situaciji i ovim

istraivanjem je pokuano da se inicira drugaiji pristup iskorienja energetskog potencijala u

Srbiji. Sa privrednog i stratekog aspekta potrebno je nauno-istraivake snage usmeriti u

pravcu razvoja iskorienja uljnih kriljaca i time smanjiti zavisnost zemlje od uvoza energenata.

Prema neki procenama, Aleksinako leite uljnih kriljaca spada u nae najperspektivnije

leite, a rezerve uljnih kriljaca se procenjuju na oko 2 milijarde tona, sa srednjim sadrajem od

9,78% ulja, te sadre ukupno oko 190.000.000 t ulja. U ovom radu razmatramo mogu nosti

istovremene eksploatacije uljnih kriljaca i preostalog mrkog uglja primenom metoda

eksploatacije irokim elom i metodom podzemne gasifikacije (PGU).Kljune rei: uljni kriljci, Aleksinaki basen, mrki ugalj, iroko elo, gasifikacija, PGU

*Ministarstvo rudarstva i energetike Republike Srbije** Rudarsko-geoloki fakultet Beograd

UVOD

Obim i struktura energetskih rezervi iresursa Srbije je veoma nepovoljna.Rezerve kvalitetnih energenata, kao to su

nafta i gas su simboline i ine manje od1% u ukupnim bilansnim rezervamaSrbije, dok preostalih 99% energetskih

rezervi ine razne vrste ugljeva, u komedominira niskokvalitetni lignit, sa ueemod preko 92% u ukupnim bilansnim

rezervama. Ovo se posebno odnosi na

lignit koji se eksploatie u rudnicima sa

povrinskom eksploatacijom, koji sa

ukupnim eksploatacionim rezervama od

oko 13.350 miliona tona, predstavlja

najznaajniji energetski resurs Republike

Srbije. Geografski posmatrano, u Koluba-

rskom basenu nalazi se 14%, u Kostolakom


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3,3%, dok Sjeniki i Kovinski basen sadresamo 2,7% ovih rezervi.[9]

Struktura tekue potronje energije u

svakoj zemlji, uslovljena je stanjem

ekonomije u svim sektorima, ukljuujui i

sektor energetike, a posebno strukturom i

intenzitetom proizvodnih i uslunih

aktivnosti, standardom i navikama

graana, kao i raspoloivou energetskim

izvorima i ekonomsko - energetskim

okolnostima u okruenju.Zbog poznatih okolnosti u proteklom

periodu, Srbija je primer zemlje, koja radi

dostizanja vieg nivoa socio-ekonomskograzvoja, mora u kratkoronom periodu dauskladi, ne samo razvoj energetike saprivredno ekonomskim razvojem, ve irazvoj energetskih proizvodnih sektora sasektorima potronje energije. Uljni kriljcisu do pre par godina spadala unekonvencionalna fosilna goriva, pa su usvetskim razmerama veoma malo istraeni.

Interesovanje za uljne kriljce i

ispitivanje mogunosti njihovog korienjau naoj zemlji datira jo od pre prvogsvetskog rata. Posle rata istraivanje je

vreno u vie navrata, ali nesistemski, takoda ni do danas nije sprovedeno do kraja.

ULJNI KRILJCI U SRBIJI

Istraenost Srbije u pogledu na uljnekriljce je veoma mala. Na teritoriji Srbijeotkrivene su pojave i nalazita uljnih kril-

jaca u sledeim regionima: Nikom (Alek-sinaki basen, reoni sela Bovna i

Prugovca, Bubuinaki i Kosaniki basen,i Svrljiki deo senonskog tektonskogrova), Zajearskom (Timoka zona senon-skog tektonskog rova, izmeu Knjaevca iBoljevca), Junomoravskom (Vranjskibasen), Kraljevakom (Kruevaki i a-

ansko-Kraljevaki basen) i Podrinjsko-Kolubarskom (Valjevsko-Mioniki basen).

Danas se samo za leite uljnih kriljaca uokolini Aleksinca moe rei da je bolje

istraeno nego druga, zahvaljujui

istranim radovima koji su obavljani za

potrebe proizvodnje mrkog uglja, te su pri

tome prikupljani podaci i o uljnim

kriljcima, na osnovu istranih buotina.

Meutim, ak i ti podaci nisu dovoljni za

konanu procenu geolokih i eksploa-

tacionih rezervi, odnosno njihovu

kategorizaciju.

Rezerve uljnih kriljaca u Srbiji, su

prema procenama, oko 810 milijardi

tona, pri emu je najvie istraeno upravo

Aleksinako leite. Veliki deo rezervi

uglja kod nas nije dostupan zbog

ekonomskih ili tehnikih razloga. Doka-

zane rezerve uglja koje nisu pogodne za

povrinsku eksploataciju iznose preko 500

miliona tona, a uljnih kriljaca, samo u

Aleksinakom leitu, ima preko 2 milijarde

tona. [1]

CILJ ISTRAIVANJA

Ve do sada poznate rezerve uljnih

kriljaca u naoj zemlji, stavljaju nas pred

zadatak da utvrdimo koliki je to energetski

i sirovinski potencijal, sa kojim moemo

raunati, na odreenom nivou sadanjih

tehnolokih rezervi, a posebno onih koje

treba oekivati u perspektivi.

Sa ciljem, da se razradi mogunost

industrijskog korienja uljnih kriljaca, a

imajui u vidu da naa zemlja raspolae

znaajnijim rezervama uljnih kriljaca i da

su rezerve uglja u naim rudarsko -

energetskim kombinatima Kolubara i

Kostolac ograniene, uraena je analiza

mogunosti istovremene eksploatacije

uglja i uljnih kriljaca iz Aleksinakog

basena.


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PODRUJE ISTRAIVANJA

Aleksinako leite mrkih ugljeva i ul-

jnih kriljaca zahvata podruje izmeu

reke June Morave i Moravice, prua se

neposredno od grada Aleksinca, u pravcu

SSZa, u duini od 10 km i zahvata

povrinu od oko 20 km2.

Karakteristiko je i jedno od retkih u

svetu, gde se slojevi uljnih kriljaca nalaze

zajedno sa mrkim ugljem i to u krovini i

podini glavnog ugljenog sloja..

Godine 1883, dolazi do eksploatacijemrkih ugljeva, dominirala je primena

kombinovane, stubno-komorne metode

otkopavanja. U zavisnosti od rudarsko-

geolokih uslova eksploatacije, razvijene

su bile dve varijante ove metode ot-

kopavanja i to :- klasina aleksinaka metoda ot-

kopavanja i- izmenjena ili modifikovana aleksi-

naka metoda

Do zatvaranja rudnika dolo je nakon

velike kolektivne nesree koja se dogodila1989. godine. Eksploatacija uglja se vrila

u Severnom reviru polja Morava kada su

primenjivane stubno-komorne metode tzv.

Aleksinake metode.Aleksinako leite podeljeno je rudar-

skim radovima na tri ugljonosna polja: Lo-gorite, Morava i Dubrava, (sl. 1) pa sui rezerve posebno utvrene za svako polje.

Do sada je na podruju Aleksinakih

rudnika i u iroj okolini izbueno preko120 buotina. Veina ovih buotina buenaje u cilju ispitivanja ugljonosnosti.

Pri odreivanju mogunosti eksploa-

tacije uljnih kriljaca moraju se imati u

vidu njihove specifinosti. Tako se prema

veliini i geolokoj sloenosti leita kril-

jaca razvrstavaju u tri grupe, pri emu se

svaka grupa deli u tri podgrupe u zavis-

nosti od debljine sloja i sadraja kerogena.

Kod odreivanja kvaliteta rezervi kriljacamora se izvriti oprobavanje slojeva, kom-

pleksan karota na svim istranim buoti-

nama, utvrivanje genetskog tipa kriljaca

i naroito, utvrivanje kvalitativnih i

tehnolokih osobina. Zahtevi koji se

postavljaju pri definisanju uljnih kriljaca

doprineli su da postoje veoma malo ut-

vrenih rezervi i resursa, dok je daleko

vei udeo potencijalnih rezervi.

Prema strukturnoj grai, Aleksinako

leite ima sinklinalnu formu, u veem

delu leita i sloenu grau u Dubravi ipodeljeno je rasedima u vie, veih,

samostalnih blokova. Slojevi su horizon-

talni, blago nagnuti pod uglom do 20o i

strmi do 90o, pa je leite svrstano u drugu

grupu. Prema postojanosti debljine i

kvaliteta krovinskih uljni kriljaci svrstani

su u I podgrupu. Podinski uljni kriljci

zbog poveane izmenljivosti debljine i

kvaliteta svrstani su u II podgrupu. [10]


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Sl. 1.Poloaj ugljonosnih polja u Alesinakom basenu

MOGUNOSTI ISTOVREMENEEKSPLOATACIJE UGLJA IULJNIH KRILJACA

injenica, da se uljni kriljci pojavljuju

na povrini, u vidu izdanaka, na veemprostranstvu po pruanju leita, od loka-

liteta Dubrava, do lokaliteta Logorite,predstavlja povoljnost za povrinsku

eksploataciju.Nepovoljnost za vee uee povri-

nske eksploatacije u ukupnim rezervamaleita predstavlja veoma strmo zaleganje

kriljaca u jednom delu leita i do 90o.

Strmo zaleganje leita uslovljava velikudubinu i preko 700m, tako da se vei deorezervi kriljaca mora otkopavati podze-mnom eksploatacijom.[5]

Visoki trokovi u podzemnoj eksploa-taciji i kompleksnost proizvodnih procesa

zahtevaju primenu savremenih sistemaeksploatacije odnosno pravilan izbor i

dimenzionisanje otkopne mehanizacije.

Osnovna karakteristika savremenih si-stema je visok stepen mehanizovanosti iautomatizovanosti svih rudarskihoperacija (otkopavanje, utovar, transport,izrada podzemnih prostorija, podgra-

ivanje i dr.), uz potovanje strogihzahteva u pogledu sigurnosti rada,bezbednosti radnika i zatite ivotnesredine.


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Da bi se izbor otkopne mehanizacijeizvrio pravilno, potrebno je sagledati sverelevantne faktore uticaja, koji mogu

delovati iskljuujue ili ograniavajue.Izbor otkopne mehanizacije je posebno

sloen kada produktivni slojevi nisuregularni, odnosno, kada nisu horizontalniili blago nagnuti i kada njihova debljina neomoguava formiranje takvih otkopnihfrontova, kojima se u jednom zahvatu, naduinama od vie kilometara moe

otkopavati.[2]

Analiza mogunosti irokoelne metode

eksploatacije

Komforne radne uslove i navedeneproizvodno-ekonomske parametre, u jam-skim uslovima su mogle da obezbede iroko

elne metode otkopavanja sa kompleksnommehanizacijom. Meutim, ove metode isavremena kompleksna mehanizacija, za-

htevaju veoma povoljne rudarsko-geolokeuslove i u leitu uglja koje se otkopava.

Rezerve ispod dubine od 50 m se moguotkopavati podzemnim (jamskim) postup-kom. Sigurno je da je za podzemnu ek-

sploataciju potrebno due vreme i viesredstava za izradu rudarskih objekata zaotvaranje leita, transport i izvoz, za ta je

neophodno izvriti dodatna ispitivanja zaizbor najpovoljnije varijante za otkopa-vanje i eksploataciju uglja i uljnih kriljacapodzemnim postupkom.

Dostignuta savremena nauka i praksapodzemne eksploatacije, definitivno je u tomprocesu dala industrijski karakter. Istina, pomnogo emu on je specifian, ali u osnovi

ima sva obeleja industrijskog procesa.Eksploatacioni zahvati u leitu meusobno

su tehnoloki povezani u jednu skladnuintegralnu celinu sa kontinuitativnim odvija-njem. Savremena tehnoloka dostignuainkorporirana su u tehnoloke faze rada i totako da komplementarno izgrauju pro-

izvodnu celinu koja sve vie gubi ekstenzivnikarakter, to je jedno od osnovnih obeleja

industrijskog procesa. Koncepcija otvaranja ipripreme leita-uvaavajui sva predhodnodata ogranienja i principe, kao i poznate

uslove eksploatacije leita, nameu sesledea okvirna tehnika reenja:

-racionalno je projektovati rudnik samin. 1,5 mil. t/g i perspektivnimpoveanjem kapaciteta na 4 mil t/g ivie;

-za kapacitet od 1,5 mil t/g i vie od4 mil. t/g neophodno je izgraditi mini-

mum 3 prostorije otvaranja. Naime,neophodno je razdvojiti izvoz uglja i

kriljca od prevoza ljudi i snadbevanjajame repromaterijalom i imati posebnuprostoriju za ventilaciju;

-prostorni poloaj leita i elementizaleganja upuuju na centralno loci-ranje glavnog izvoznog i ventila-

cionog sistema; izbor mikro lokacijeobjekata je u funkciji morfologijeterena, komunikacija, uslova gradnjepovrinskog kompleksa i drugo, pa jeteko preciznije dati tehnike elementekoji definiu tehnologiju i trokoveizgradnje, vee se isti dati procenom

na osnovu cene slinih objekata udrugim rudnicima.

Svim poznatim i pretpostavljenimuticajnim faktorima odgovara sistemotvaranja koji obuhvata:

-Glavni izvozni niskop, sa povrinompoprenog preseka od oko 14 m

2,

padom oko 15, ukupne duine do1000 m;

-Ventilacioni niskop, sa povrinompoprenog preseka od oko 10 m

2 i

padnim uglom od oko 30 (paralelansloju) i duine do 800 m;

-Servisno vertikalno okno za prevozradnika, opreme, repromaterijala i

delova dubine oko 400 m;

Iz podruja otvaranja, neophodno jeostvariti poprene veze sa produktivnimslojevima, na meusobnom rastojanju od 40do 60 m. Spajanje horizonata ostvaruje seizradom kosih prostorija, najmanje tri,

lociranih u produktivnim slojevima, u ciljuuspostavljanja protonog provetravanja. Daljisistem pripreme, ostvaruje se izradom


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paralelnih hodnika do granica leita, ukrovinskom i podinskom bloku. Usposta-vljanjem poprenih veza meu pripremnim

hodnicima stvaraju se uslovi za formiranjeirokoelnih mehanizovanih otkopa. U datim

uslovima, uvaavajui zahteve proizvodnefunkcionalnosti i sigurnosti rada, smatra sesvrsishodnim dvokrilno otkopavanje.

Namee se logina dilema, moe li ovotehniko reenje biti primenjeno u us-lovima uljnih kriljaca u Aleksincu.

Poznavajui fiziko-mehanika svojstvakriljaca i na bazi iskustva pri eksploataciji

uglja u jami Morava, moe se dati sigu-ran pozitivan odgovor. [4]

Analiza mogunosti primene podzemne

gasifikacije

Viedecenijska svetska iskustava, kadase govori o podzemnoj gasifikaciji uglja(sl. 2), ukazuju, da se radi o ekoloki istoj

tehnologiji kompleksnog iskorienja ugljai to u potpuno neiskorienim ili u

nekorienim ugljenim slojevima ilidelovima leita.

Imajui u vidu kvantitet i kvalitet

energetskih resursa kojima raspolaemo, aposebno izraenije potrebe za toracionalnijim korienjem primarnih

energetskih resursa (dakle, ne samosekundarnih), nali smo se u situaciji daosvajamo tehnologiju eksploatacijevanbilansnih rezervi, kao i otkopnihostataka bilansnih rezervi. Metoda bezalternative za takve rezerve uglja jepodzemna gasifikacija uglja.

Sam proces gasifikacije mrkih ugljeva

je proces prerade organske materije uglja ugasovite produkte. Gasifikacija mrkih

ugljeva se moe odvijati i kod ugljeva saniskim stepenom hemijske zrelosti, te sena taj nain ugalj potpuno oslobaa odmineralnih primesa i vode. Gasifikacija semoe odvijati dvojako: podzemnom

gasifikacijom uglja-PGU ili u gasgeneratorima.

Pri opredeljenju za aktivnosti na tomplanu, najvaniji je pristup to savesnijemizboru optimalne lokacije za PGU. Pri

tome je neophodno sagledati koliine ugljakoje e se moi izgasifikovati, a time i

odrediti koliinu ukupno proizvedenog

gasa iz PGU.Dosadanja iskustva su pokazala de se

podzemnom eksploatacijom uglja iskoristioko 30-35%, a da praktino ostajenaputeno oko 65-70%, to bi se saaspekta eventualnog postojanja vikaenergetskih resursa i razumelo, ali nijetako, pogotovo zbog brige za budua

vremena. Takvo stanje bi se moglo iprihvatiti, ali pojavljivanjem novih ili al-

ternativnih tehnologija, kao to je i ova PGU, odavno poznata (licencu PGU je jo1974. godine SSSR prodao SAD), sa kom-parativnim prednostima u odnosu na kon-vencionalne metode eksploatacije (koje uosnovi karakterie teak rudarski rad, iz-raen odreeni drutveni interes, nedovol-

jna rentabilnost, zatita okoline, emisijagasova, itd), ozbiljno nas opredeljuje zaove nove tehnologije.

Podzemna gasifikacija uglja, auto-

termiki proces, obuhvata proces dega-

sacije, odnosno pirolize i samu gasifikaciju.

Ti procesi nastaju kao rezultat uticaja visoketemperature i upravljanja sagorevanja uglja

pri dovoenju sredstava za gasifikaciju, koja

je najee vazduh, vodena para sa

vazduhom u odreenom odnosu, te vazduh

ili vodena para obogaeni kiseonikom, ili

pak sam kiseonik. Danas uglavnom egzi-

stiraju dve poznate metode PGU.

Metoda bez podzemnih prostorija, kojase zasniva na buenju buotine sapovrine kroz slojeve i provoenjemgasifikacije dovoenjem gasifikujueg

agensa kroz buotinu, odnosno kanala,a odvoenjem produkta gasifikacijekroz produkcionu buotinu;

Metode iz podzemnih prostorija ukojoj se sloj, preostao nakon izradesigurnosnih stubova, gasificira korie-njem izraenih prostorija.

Prva grupa metoda (buotinska PGU)je uglavnom aktuelna za korienje vanbi-


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lansnih rezervi uglja, a druga za gasifikacijuzaostalih sigurnosnih stubova, odnosnootkopnih ostataka bilansnih rezervi, posle

zavrene jamske eksploatacije. Od buo-tinskih metoda obino su u primeni: filtra-

ciona, kanalna i protona metoda.Uglavnom je rasprostranjena filtraciona

metoda, nakon prethodnog zapaljenja reak-cione zone. U amerikim eksperimentimaprimenjuje se kanalna metoda, s tim, da sekanali zapaljuju filtracionom metodom.

Podzemna gasifikacija uglja, karakte-rie se stepenom iskorienja uglja, koji

predstavlja odnos gasifikovanog uglja pre-ma ukupno raspoloivoj koliini uglja zaPGU. Termika efikasnost procesa je de-

finisana odnosom toplotne moi dobijenegasne smee prema toplotnoj moi uglja,

iz koga je nastala smea, svedeno na ek-vivalentne dimenzije, to zavisi od vrstegasifikujueg agensa, njegovog pritiska itemperature, te osobine uglja za gasifi-kaciju, dubine zaleganja sloja, vlanostiuglja, kao i tektonskih uslova u leitu.

Sl. 2.Pojednostavljena ema PGU procesa

Cilj PGU je izdvajanje toplotneenergije iz uglja, u vidu gorivog gasa, iliza proizvodnju gasa za sintezu. Procestransformacije energije se odvija putempotpunog i nepotpunog sagorevanja uglja ivodeno-gasnog procesuiranja zaarenog

koksa na samom mestu zaleganja ugljaputem vazduha, kiseonika, pare ili njiho-

vom meavinom. Tehnoloki proces PGUsastoji se iz pripreme ugljenog sloja zagasifikaciju i samog proces gasifikacije.

Priprema ugljenog sloja za gasifikacijusastoji se u izradi kosih i vertikalnih buo-tina sa povrine terena. Do povlate ug-

ljenog sloja buotine se zacevljuju, a kon-

takt cevi sa sredinom kroz koju se bui icementira. Buotina kroz ugljeni sloj se nezacevljuje. Dno buotine je na oko 0,5 mod podine ugljenog sloja. Konstrukcijabuotinskog sistema, raspored buotina injihov prenik odreuju se konkretno za

svako leite na osnovu geolokihkarakteristika leita. Za formiranje kanala

izmeu buotina primenjuje se dirigovanobuenje sa kojim se kroz sloj izbuihorizontalna buotina, pri podini ugljenogsloja, koja povezuje vertikalne buotine.Frakturisanje ugljenog sloja vri sepomou vazduha visokog pritiska,

hidraulino ili plameno, da bi se obezbedio


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prolaz vazduha kroz pore u uglju. Ugljenisloj se potpaljuje ubacivanjem zaarenogkoksa kroz buotinu i uduvavanjem

vazduha niskog pritiska ili brenerom.Tokom pirolize, ugalj se ari i oslobaa

smole, ulja, nie ugljovodonike i volatile.Gasifikacija se javlja kad vodena para,kiseonik, ugljen-dioksid i vodonik reagujusa uarenim ugljem.

Metan je proizvod pirolize i njegovuprodukciju pospeuju nie temperature i

vii pritisci. Rezultati ukazuju da povienipritisak uzrokuje prodiranje pirolize kroz

ugljeni sloj i tako podspeuje gasifikacioniproces. Reakcije oksidacije ugljenikadominiraju na niim temperaturama iniim pritiscima, sto vodi veem sadrajuugljendioksida u proizvedenom gasu imanjoj toplotnoj vrednosti. Ovakvi uslovisu tipini za ranije, relativno plitke probe

PGU.Osnovni princip koji se koji bi se

mogao primeniti za Aleksinako leiteuglja i uljnih kriljaca je u tome da se vrigasifikacija uglja sa istim kiseonikompod pritiskom do 20 bara, a da se toplota

dobijena ovim postupkom koristi zavelovanje uljnih kriljaca delimino u

podini ugljenog sloja, a najveim delomkrovinskih uljnih kriljaca.

Uobiajeni postupak za velovanjekriljaca je da se vri gasifikacija uglja ilivrstog ostatka pri preradi produkatavelovanja uljnih kriljaca i da produktigasifikacije svojom toplotom vrevelovanje kriljaca u viem delu ahte.

Priroda je uinila da Aleksinakoleite ima ba takav raspored (jedino tobi povoljnije bilo da podinski kriljci ne

prelaze debljinu ugljenog sloja).Postupak bi bio sledei:Gasifikacijom ugljenog sloja

oslobaaju se produkti gasifikacije CO,

H2, CH4 sa temperaturom od oko 700C iugljeni sloj se sa svoje debljine od 6 msvodi na debljinu od cca 0,8 m (zavisno odsadraja pepela). Usled toga, dolazi doprirodnog zaruavanja krovinskihkriljaca, njihove dezintegracije i pripreme

za velovanje. Vreli produkti gasifikacijevre velovanje povlatnih uljnih kriljacaprolaenjem kroz dezintegrisanu masu

kriljaca. Podinski kriljci se zagrevajuprolaenjem toplote.

Kod Aleksinakih leita predlae segasifikacija sa istim kiseonikom (dobijanjemodifikovanim postupkom Linde-Frenkl).Predlae se modifikacija sa prethodnimhlaenjem vazduha korienjem toplotedobijene hlaenjem gasova iz buotine.

Gasifikacija istim kiseonikom umestovazduhom predlae se s obzirom na daleko

bre odvijanje procesa, veeg koeficijentaiskorienja toplote, i dobijanja gasovitih

produkata daleko vee toplotne vrednosti.Gas dobijen gasifikacijom uglja

kiseonikom i uz pritisak koji normalno imaoko 16,7 MJ/m3 obogauje se gasovitimproduktima velovanja uljnih kriljaca te

dostie vrednost od oko 20,9 MJ/m3. Kao

takav spada u red srednjekalorinih gasovai moe se direktno koristiti za pogontermoelektrane-toplane kao i u industrijskesvrhe. Takoe, mogue su raznekonverzije, kao i dobijanje tenih

ugljovodonika.U procesu preiavanja gasa, dobijaju

se: fenoli, amonijak, benzoli i mnogi drugiprodukti, dok se iz sumporvodonika lakodobija ist sumpor.[11]

ZAKLJUAK

Aleksinako leite uglja i uljnihkriljaca spada u leita vrlo sloenegeoloke strukture, sa ograniavajuimelementima za primenu metodaotkopavanja irokim elom i tehnologije

mehanizovanog otkopavanja.Prema broju istraenih tehnikih

parametara, neophodnih za projektovanjepodzemnih proizvodnih sistema ikonstrukcije otkopa, ovo leite spada ugrupu nedovoljno istraenih leita.

Ova injenica je utvrena kroz analizuraspoloive tehnike dokumentacije i

prouzrokuje mnoge tekoe i upuuje nanepouzdane ocene i prognoze tehnikih


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veliina i tako

e zahteva neophodnaistraivanja radne sredine, u poetnom

periodu rekonstrukcije rudnika.

Nakon zatvaranja Aleksinakog rudnika,preostalo je kroz bilansne i vanbilansne

rezerve 27,5 mil.t. kvalitetnog mrkog uglja.Iz svetskih industrijskih iskustava sa PGUpoznato je da je stepen iskorienjanapadnutih slojeva uglja 72-96%. Akoraunamo sa svega 80% takve iskoristivosti,ostaje otvoreno miljenje da bi se pomou

PGU u Aleksincu iskoristilo 22 mil. t uglja.Postojanje uljnih kriljaca, direktno

naleglih na ugalj, omoguavali bipoveanje efikasnosti procesa PGU.

Naime, gubitak toplote iz procesa PGU nakrovinu e proizvesti dodatne ugljovo-donine gasove i tenosti. Vei deo tihtenosti e krekovanjem proizvestidopunski deo ugljovodoninih gasova.

Takvo kombinovano dobijanje ugljovo-doninih gasova iz uljnih kriljaca pove-ava toplotnu mo gasa dobijenog iz PGU,a omoguava i dobijanje odreene koliinenafte, kao nusproizvoda u ovom procesu.

Da bi se ostvarila proizvodnja na bazi

ve

dokazanih geolokih rezervi, potrebnoje nastaviti sa istraivanjem naina

dobijanja sintetike nafte iz uljnih kri-ljaca, uz konsultaciju inostranih firmi, ijasu iskustva i osvojene tehnologije u ovojoblasti jo uvek neprevaziene. Pri tomese mora imati u vidu, da je realizacijaeksploatacije ovih potencijala limitirana,kako sadrajem uljne frakcije koja diktiratehnologiju, prostornim zahtevima i

uslovima vezanim za ivotnu sredinu, aposebno u postizanju rentabiliteta zapojedina leita i nalazita, pri emu u

osnovi rentabilitet zavisi od cene nafte nasvetskom tritu, koja bi za uslove naihleita morala biti znatno vea u duemvremenskom periodu. To ipak znai da

ovaj resurs zasluuje panju i prouavanjekao alternativni energetski potencijal.

U sluaju Aleksinakog leita, pored

pravilne raspodeljenosti korisnih i tetnih

komponenti, presudan uticaj na ekonom-

ske uslove eksploatacije imae nagib idubina zaleganja slojeva, tj. morfoloke

karakteristike rudnog tela. Naravno, pose-

bne analize je potrebno napraviti za iskro-

rienje korisne materije i velikih koliina

uljnih kriljaca koje se nalaze ispod samim

naseljenih mesta (Aleksinac, Subotinac,

Vakupac, itd) U ovim delovima leita,

tkz. zatitnim stubovima, proces PGU

moe predstavljati najoptimalnije reenje.

Koliine od oko 3,8 milijardi

bituminoznih laporaca, koji se nalaze u

povlati uljnih kriljaca sa oko 4-5%

organske materije, takoe mogu bitipredmet posebnih istraivanja, a budue

vreme e ve pokazati da li se oni mogu

tretirati zajedno za kriljcima ili odvojeno.

LITERATURA

[1] D. Sokolovi, Istraivanje redosleda i

dinamike istovremenog podzemnogotkopavanja leita uglja i uljnihkriljaca u funkciji optimalnogiskorienja energetskog potencijala,

Magistarska teza, Beograd, 2009.[2] D. Gagi, Ispitivanje tehnikoekonom-

skih uslova za prelaz na tehnologiju

mehanizovanog otkopavanja u podzem-noj eksploataciji leita uglja, Doktorskadisertacija, Beograd, 1986.

[3] D.Vitorovi, I. Mijatovi, D. Mati,Perspektivne mogunosti korienjauljnih kriljaca, Srpska AkademijaNauka i Umetnosti, Beograd, 1968.

[4] M. Ivkovi, V. Ljubojevi. A.Mladenovi, Geoloke karakteristike

leita uljnih kriljaca Aleksinakogpodruja, Beograd, 2001.

[5] Elaborat o rezervama uljnih kriljaca

u Aleksinakom leitu, polje-Morava i Logorite, Knjiga III,Ugaljprojekt, Beograd 1986.

[6] Elaborat o rezervama uljnih kriljaca uAleksinakom leitu, polje DubravaKnjiga I, Ugaljprojekt, Beograd, 1984.


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[7] Studija: Analiza ekonomske opravda-nosti eksploatacije i korienja uljnihkriljaca za snabdevanje nia i

aleksinca toplotnom i elektrinomenergijom, RFG, Beograd, 2003.

[8] Stepen istraenosti uljnih kriljaca uAleksinakom lokalitetu sa prikazompotreba na daljem istraivanju i mogu-

nou zasnivanja rudarske eksploa-

tacije, URMUS, Beograd, 1974.

[9] Strategija razvoja energetike Repu-

blike Srbije do 2015. godine, str. 1-6,Ministarstvo rudarstva i energetike,

Beograd, 2005.

[10] Studija tehnikotehnolokih iekonomskih reenja i uslova dalje

eksploatacije uglja u jami Morava,

rudnika uglja Aleksinac, Rudarskiinstitut Beograd, 1986.

[11]M. Ivkovi, Uvoenje sistemapodzemne gasifikacije u delovimaleita Aleksinakog podruja,Zbornik radova meunarodnog

savetovanja, Zlatibor, 2008.


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No 1, 2010. MINING ENGINEERING47

COMMITTEE OF UNDERGROUND EXPLOITATION OF YU ISSN: 1451-0162

THE MINERAL DEPOSITS UDK: 622

UDK: 622.337:622.33(045)=20

Dejan Sokolovi*, edomir Belji*, Duan Gagi**

INVESTIGATION OF POSIBILITES FOR SIMULTANEOUS

EXPLOITATION OF COAL AND OIL SHALE IN THE

ALEKSINAC BASIN

Abstract

Following the efforts and activities in other countries that have oil shale, we can see, that this en-ergy potential is intensive and accounts for winning the technology of their economic exploitationand processing, in order to obtain liquid and gaseous hydrocarbons and other valuable products.

The scope and structure of energy resources and energy in Serbia is in unenviable situationand this research attempts to initiate a different approach for utilization the energy resources in

Serbia. With the economic and strategic aspects is need to scientific research forces directed to-wards development of utilization the oil shale and reduce dependence on energy imports from the

country.According to some estimates, the Aleksinac deposit of oil shale is one of our most promising

deposits, and oil shale reserves are estimated at about 2 billion tons, with high content of 9.78%

oil, and contains total of about 190.000.000 t oil. In this paper, we are considering the possibilityof simultaneous exploitation of oil shale and remaining brown coal using the mining method oflongwall and the method of underground gasification.

Key words: Oil shale, Aleksinac deposit, brown coal, longwall mining, gasification, UCG

* Ministry of Mining and Energy of Republic Serbia** Faculty of Mining and Geology Belgrade

INTRODUCTION

The scope and structure of energy re-serves and resources of Serbia is very un-favorable. Reserves of high-quality energysuch as oil and gas are symbolic and are

less than 1% of total balance reserves ofSerbia, while the remaining 99% of en-

ergy reserves are various types of coal,which dominates low quality lignite, withthe participation of over 92% of total bal-

ance reserves. This is especially true oflignite that is exploited in the mines withsurface mining, the exploitation by total

reserves of about 13,350 million tons, themost important energy resources of the

Republic of Serbia. Geographically speak-ing, in the Kolubara basin is 14%, in theKostolac basin 3.3%, while the Sjenicaand Kovinski basin contain only 2.7% ofthese reserves. [6]

The structure of current energy con-

sumption in every country, caused by the

state of economy in all sectors, includingenergy sector, especially the structure andintensity of production and service


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activities, standards and habits of citizens,as well as the availability of energy re-sources and economic - energy conditions

in the environment.Because of known circumstances in

the past, Serbia is an example of the coun-try, which is forced in the short term toharmonize not only energy developmentwith the business economic development,but development of energy productionsector with the sectors of energy con-

sumption in order to achieve higher levelsof socio-economic development. Oil

shales, a few years ago, fell in the "uncon-ventional" fossil fuels, and are of world-wide very little explored.

Interest in oil shale and testing capa-bilities their use in our country dates backto before the I World War. After the War,research was done on several occasions,

but not systematically, so it has not beencarried out to the end.

OIL SHALE IN SERBIA

Site researches of oil shale in Serbia

are very small. On the territory of Serbiaoil shale sites were discovered in the fol-lowing regions: Ni (the Aleksinac Basin,regions village Bovan and Prugovac,

Bubunica and Kosanica Basin), Zajear(Timok zone between Knjaevac and Bol-jevac), South Moravic (the Vranje basin),Kraljevo (the Kruevac and aak-Kraljevo basin) and Podrinje - Kolubara(the Valjevo-Mionica basin).

Today, only for the oil shale depositaround Aleksinac we can say it is betterresearched than others, thanks to investi-

gative work that are undertaken for theproduction of coal, and thereby collecteddata on oil shale, on the basis of prospect-ing the drillholes. However, even thesedata are not sufficient for final evaluationand exploitation of geological reserves

and their categorization.

Reserves of oil shale in Serbia, accord-ing to estimates, are approximately 8-10billion tons, where the Aleksinac deposit

is the most researched. Large reserves ofcoal in our country are not available due

to the economic or technical reasons.Proven coal reserves that are not suitablefor surface exploitation amounts exceed-ing 500 million tons, and oil shale are onlyin the Aleksinac deposit, over 2 billiontons. [1]

AIM OF RESEARCH

For the currently known oil shale re-serves in our country, put us to the task to

determine what is the energy and raw po-tential, with which we can count on a cer-tain level of current technological re-serves, especially those to be expected inthe future.

In order to elaborate the possibility for

industrial use of oil shales while bearingin mind the fact that our country has a

considerable oil shale reserves, and thatthe coal reserves in our mining the en-

ergy plant ''Kolubara" and "Kostolac" lim-ited, made the possibility of simultaneousanalysis of coal and oil shale from theAleksinac basin.

RESEARCH AREA

The Aleksinac deposit of brown coaland oil shale overtakes the area betweenthe River Morava and the South Moravicaoffers directly from the town of Aleksinac,in the direction of NNW, the length of 10km and covers the area of about 20 km2.

It is one of the few in the world, wherethe layers of oil shale stored together with

brown coal, in floor and overlie main coallayer. In 1883, the exploitation of browncoal was dominated by the combined,room-pillar mining methods. Dependingon the mining-geological conditions of


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exploitation, two variants of this methodof mining were developed as well as:

- the classic Aleksinac mining method,and

- the changed or modified Aleksinacmethod

The closure of the mine, occurred after

the large collective accident in 1989, the

coal exploitation was done in the north

area of ''Morava'' field, where the room-

pillar mining methods were applied, so

called the Aleksinac methods.

The Aleksinac deposit is divided by

mining works into three coal fields: the"Logorite", "Morava" and "Dubrava"

(Fig. 1) and the reserves are specially de-

termined for each field.

Until now, the area of Aleksinac mines

in its surroundings drilled over 120 drill-

holes. Most of these drillholes were drilled

in order to investigate the coal.In determining the possibility of oil

shale exploitation, their characteristicshave to be taken into account. Thus, ac-cording to the size and complexity of the

geological oil shale deposits divided into

three groups, with each group divided intothree subgroups depending on the thick-

ness of the layer and the content of kero-

gen. In determining the quality of oil shale

reserves, exploring layers, must be done,

complex mapping of all exploratory drill-

holes, determine the genetic type of oil

shale and in particular, to determine the

qualitative and technological characteris-

tics. Requirements are set in definition of

oil shale contributed, to exist very few

established reserves and resources, while

the far greater share of potential reserves.

According to the structural material, theAleksinac deposit has a syncline form, in

most of the deposits and complex struc-

ture in the "Dubrava", and is divided into

several thrust faults, major, independent

blocks. Layers are horizontal, slightly

sloping angle to 20o

and sink to 90o, and

the deposit belong to second group. The

thick consistency and quality, of overlie

oil shale, there are classified into the sub-

group I. The floor oil shale, due to the

increased thickness variability and quality

were classified in the subgroup II. [11]


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Figure 1. Shows the geographical location - view from the geographic information system(GIS software package ArcView 9.2) and contours of coal fields on the geological map in the

Aleksinac basin.

POSIBILITES FOR SIMULTANEOUS

EXPLOITATION OF COAL AND OILSHALE

The fact that oil shale appears on thesurface, in a form of offspirngs, the more

space by providing the deposit of the field"Dubrava", to the field "Logorite", pre-

sents the benefits for surface exploitation.Skid for greater participation of surface

exploitation of reserves in total deposits, is

very steep sink of oil shale in one part of thedeposit, up to 90

o. Steeply sink of deposits

causes a great depth, over 700m, so that mostof the oil shale reserves must be exploitedusing the underground methods. [7]

High costs in the underground opera-tions and complexity of production proc-


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esses, require the use of modern systemsof exploitation and proper selection andsizing exploitation machinery. The main

characteristic of modern systems is a highdegree of mechanization and automation

of mining operations (mining, loading,transport, construction of undergroundfacilities, supporting, etc.), with respectthe strict requirements in terms of worksafety, worker safety, and environmentalprotection.

For suitable selection of excavationmechanization, it is necessary to ob-

serve the all relevant factors of influ-ence that can affect exclusive or limit-ing. Features of excavation machinery isparticularly complex when the produc-tive strata are not regular, i.e., whenthey are not horizontal or slightly slop-ing when their thickness does not allow

the formation of such excavation fronts,which in one grip, the length of severalkilometers can excavate [2].

Analysis of longwall mining exploitation

opportunities

Comfortable working conditions andset of production-economic parameters, inmine conditions could provide the long-

wall mining methods with complex ma-chinery. However, these methods andmodern machinery complex, requiring avery favorable mining-geological condi-tions in the coal deposit that is mined.

Reserves below a depth of 50m can beexcavated using the underground method. Itis certain that the underground exploitation

is longer and more resources for develop-ment of mining facilities for the opening of

the deposit, transport and export, for whatthe additional tests are necessary to be car-ried out to select the best variant for miningand exploitation of coal and oil shale usingthe underground method.

Reached by modern science and prac-tice of underground exploitation, certainly

in the process gave the industrial charac-ter. True, in many ways it is specific, butbasically has all the characteristics of in-

dustrial processes. Operational proceduresin each deposit are technologically relatedto a single integral whole with harmonious

development of continuity. Modern tech-nological developments are incorporated

into the technological phases of work andto build complementary production unit,which lost more extensive character, thatis one of the basic characteristics of indus-trial process. Opening concept and prepar-ing the deposit-taking into account all pre-

vious data limitations and principles, aswell as known conditions of exploitation

of deposits, impose the following ap-proximate technical solutions:

- rational design is mine with min. 1.5

mil. t/year with prospective increase inthe capacity of 4 mil. t/year or more;

- capacity of 1.5 mil. t/year and morethan 4 mil. t/year are necessary to buildminimum of 3 open rooms, namely, itis necessary to separate the export of

coal and oil shale from the transporta-tion of people and supply of raw mate-rials and the pits have a special roomfor ventilation;

- geographical location of deposit andslop elements pointing to the centrallocation of the main export and ventila-

tion systems; selection of micro-sitefacilities in the function of the mor-phology of the terrain, communica-tions, construction conditions of sur-face complex and more, and it is diffi-cult to give precise technical elementsthat define the technology and costs ofconstruction, but will give the same

assessment of the cost of similar facili-ties in other mines.

All known and presumed influentialfactors corresponding to the opening asystem that includes:

- Main export decline slope, with cross-sectional area of about 14 m

2, falling

about 15o, the total length up to 1000

m;- Ventilation decline slope, with cross-

sectional area of about 10m2 and fall


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angle of 30

o

(parallel to layer) and upto 800 m;- Service vertical shaft for transport of

the employed, equipment, materialsand parts of the depth of about 400 m;

From the opening area, it is necessaryto achieve transversal connection withproductive layers, the mutual distance of

40 to 60 m. Merging horizons achievedwith making slope rooms for at least three,

located in the productive layers, in order toestablish flow ventilation. Further prepara-tion of the system, achieved production of

parallel corridors to the limits of the de-posit, in overlie, and floor block. The es-tablishment of cross-links between pre-

paratory corridors creates the conditionsfor the formation of longwall mechanized

pits. In the given conditions, taking intoaccount the production requirements offunctionality and security work, consid-ered to be purposeful doors mining.

A logical dilemma is imposed, whetherthis technical solution could be imple-mented in terms of oil shale in Aleksinac.

Knowing the physical-mechanical proper-

ties of oil shale and based on experience inthe exploitation of coal in the field, "Mo-rava", can be given to secure a positiveresponse. [5]

Analysis of underground gasification

opportunities

Many decades of world experiences,when speaking about the undergroundgasification of coal (Fig. 2), indicate that itis environmentally clean technology andcomplex utilization of coal in a completely

unexploited or unused coal layers or partsof the deposit.Given the quantity and quality of en-

ergy resources at our disposal, and espe-cially prominent as the need for rationaluse of primary energy resources (i.e., notjust secondary), we found the situation toconquer the technology exploitation off-

balance reserves and remains excavatingbalance reserves. For such underground

coal reserves, the coal gasification is themethod without any alternative.The process of gasification of brown

coal is processing of organic matter intothe coal gas products. Gasification of

brown coal could be also carried out withthe coals of low degree of chemical matur-ity, and thus the coal is completely free ofmineral inclusions and water. Gasificationcould be carried out by two ways: the un-derground coal gasification UCG, or in

the gasgenerators.Determination the activities in this

area, the most important approach is themost conscientious choice for optimal lo-cation of PGU. When it is necessary toobserve the quantity of coal that would begasified, and thus determine the totalamount of produced gas by the UCG.

Previous experiences have shown that

the underground mining of coal use around30-35%, and virtually abandoned remainsabout 65-70%, which would point to pos-sible existence of surplus energy resourcesand understanding, but it is not so, espe-cially because of concerns for the future

time. This situation could be, and accept,but the appearance of new or alternative

technologies, such as is this - UCG, longknown (UCG license was sold by the So-viet Union to the USA in 1974), with acomparative advantage over the conven-tional methods of exploitation (which inbasically characterized by difficult miningoperation, expressed the social interest,insufficient profitability, environmental

protection, emissions, etc.), seriously wechoose for these new technologies.

Underground gasification of coal,

autotermic process, includes the process ofdegasification, or pyrolysis and gasificationitself. These processes occur as the resultof impact the high temperature and man-

agement of coal combustion at bringing thefunds for gasification that is usually air,water vapor with air in a certain respect,and air or oxygen-enriched water vapor, oroxygen. Today, the two known UCGmethods exist.


17/20


method without underground rooms,based on drilling the drilholes fromsurface through layers and bringing

gasification, enforcement gasificationagent through wells, or channel, and

removing product gasification throughproduction well;

methods of underground rooms wherethe layer, remaining after the comple-tion of the security pillars, gasificationmade using the premises.

The first group of methods (wellsUCG) is mainly for current use the off-

balance reserves of coal gasification andother outstanding security pillars and rem-nants exploited balance reserves, after fin-ishing underground exploitation. Sincewells methods are usually applied in: fil-

tering, channel and flow method.

The mostly widespread is the filteringmethod, after the previous inflammatoryreaction zone. The American experiment is

the applied channel method, but, to chan-nel inflame with filtering method.

Underground gasification of coal,characterized by the efficiency of ex-ploited coal, which represents the ratio ofgasified coal to the total amount of coalinput of the UCG. Thermal efficiency ofthe process is defined by the relation of

thermal power obtained by heating a mix-ture gas of coal power, which made a mix-

ture, reduced to the equivalent size, de-pending on the type of gasified agent, itspressure, and temperature, and propertiesof coal gasification, layer depth, humidityof coal, and tectonic conditions in the res-ervoir.

Figure 2. Simplified UCG process scheme

The aim of the UCG is to extract thermal

energy from coal, as fuel gas or synthesis gasproduction. The process of transformation ofenergy takes place through the complete andincomplete combustion of coal and water-

gas processing burning fiery coke at the site

of coal slope, by air, oxygen, steam, or theirmixture. UCG technological process consistsof preparing for the gasification of coal layerand the process of gasification.


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Preparing a coal layer for the gasifica-tion are consists in making slope and ver-tical wells to the surface terrain. To floor

of the coal layer through wells are pipesset, and contact with middle tube through

which the drill and cementing. Wellthrough the coal layer is not pipes set. Thebottom of the well is about 0.5 m from thefloor of coal layer. Construction of wellsystem, wells schedule and their diameterare determined specifically for each de-

posit based on geological characteristics ofthe deposit. The formation of the channel

between wells is applied with controlleddrilling with which through layer well ahorizontal well, to the floor of coal layer,which connects the vertical wells. Frac-tures of coal layer are performed usinghigh pressure air, hydraulic, or fire, to en-sure the passage of air through the pores in

coal. Coal layer is ignite inserting glowingcoke through a well and insufflation of air,at low pressure or with brener.

During pyrolysis, coal is glowing andfrees resins, oils, lower hydrocarbons andvolatile. Gasification occurs when water

vapor, oxygen, carbon dioxide and hydro-gen react with hot coal.

Methane is a product of pyrolysis andboost production of its lower temperaturesand higher pressures. The results indicatethat the increased pressure causes the pene-tration the pyrolysis through coal layer andso stimulates gasification process. Carbonoxidation reactions dominate at lower tem-peratures and lower pressures, which leads to

higher carbon dioxide content in the pro-duced gas and lower heating value. Suchconditions are typical of earlier, relatively

shallow UCG probe.Basic principles that could be applied

to Aleksinac deposit of oil shale and coalis that the coal gasification is carried out

with pure oxygen under pressure to 20 bar,and that the heat obtained by this proce-dure is used for reduced of oil shale par-

tially in floor of coal layer and for themost part in overlie of oil shale.

The usual procedure for reduce oilshale is to done gasification of coal or thesolid rest of the processing of reduced ofoil shale products and that gasificationproducts with its heat made reduced oilshale in the higher part of the manhole

himself.Nature is made to Aleksinac deposit

has just such an arrangement (the onlything that would be favorable is that thefloor oil shale does not exceed the thick-ness of coal layer).

The procedure would be as follows:Gasification of coal layers are released

gasification products CO, H2, CH4 with a

temperature of 700 C and coal layer withits thickness from 6 m down to thicknessof approximately 0.8 m (depending on theash content). As the result, there is a natu-ral crashing of overlie of oil shale, theirdisintegration and prepare for reduce. Hot

products of gasification perform reduce ofoverlie oil shale passing through the mass

of disintegrated oil shale. Floor oil shale isheated with passage of heat.

In the Aleksinac deposits are proposedgasification with pure oxygen (to obtainthe modified procedure of Linde-Frenkl).It is proposed modifications to the previ-

ous air cooling using heat obtained bycooling gas from wells. Gasification with

pure oxygen rather than air, it is suggesteddue to the much faster conducting theprocess, greater utilization coefficient of

heat and gaseous products to obtain fargreater heat value.

Gasification of coal derived gas andoxygen with the pressure that normally has

about 16.7 MJ/m3

enriches the gaseousproducts oil shale reduce and reaches avalue of about 20.9 MJ/m

3. As such, it

belongs to medium caloric gas and can be


19/20


directly used to drive power plants as wellas industrial heating purposes. Also, thereare various conversion and obtaining liq-

uid hydrocarbons.In the process of purification of gas,

the followings are obtained: phenols, am-monia, benzenes, and many other prod-ucts, while pure sulfur is easily producedfrom sulfur hydrogen. [4]

CONCLUSION

The Aleksinac deposit of coal and oilshale is one with very complex geological

structure, the limiting elements for theimplementation of mining methods andtechnology, like long wall mining metodand mechanized mining technologies.

The number of investigated technical

parameters necessary for designing pro-duction systems and underground miningconstruction, this deposit belongs to agroup of under-explored deposits.

This fact was established through

analysis of available technical documenta-

tion and cause many difficulties and leads

to unreliable assessments and forecasts of

technical size and also requires the neces-

sary research work environment, in the

initial period of reconstruction of the mine.After closing the Aleksinac mine,

through the remaining balance and off-balance reserves of 27.5 million ton ofquality lignite coal. From the world ofindustrial experience with the UCG isknown that the efficiency "attacked" thelayers of coal 72-96%. If the count with

only 80% of such usage, it remains anopen view to using the UCG in Aleksinac,

will benefit around 22 million tons of coal.The existence of oil shale, directly ad-jacent to coal, permitted to increase theefficiency of the process of UCG. Namely,the heat loss from the process of UCG onoverlie of layers will produce additionalhydrocarbon gases and liquids. Most of

these liquids will produce additionalcracking of hydrocarbon gases. Such com

bined of hydrocarbon gases getting fromoil shale, increases the thermal power ofthe gas obtained from UCG, and allows

obtaining a certain quantity of oil, as wellas by-products in this process.

In order to achieve the production based

on already proven geological reserves, it is

necessary to continue to research ways of

obtaining synthetic oil from oil shale, with

the consultation of foreign companies,

whose experience and gained technology

in this area is still unsurpassed. It must be

borne in mind that the realization of the

exploitation of these resources is limited,as content of oil fractions, which dictates

the technology, space requirements and

conditions related to the environment, par-

ticularly in achieving the profitability of

individual deposits, while essentially

breakeven depends of oil prices on the

world market, which would be the condi-

tions of our deposit had to be significantly

higher over a longer period of time. That

still means that this resource deserves at-

tention and study as an alternative energy

potential.In the case of the Aleksinac deposit, in

addition to regular distribution useful and

harmful components, a decisive influence

on economic exploitation will slope and

depth of layers, i.e. morphological charac-

teristics of ore bodies. Of course, specific

analysis is needed to make the exploiting

useful materials and large amounts of oil

shale that are under very populated places

(Aleksinac, Subotinac, Vakupac, etc.) In

these parts of deposits, so called the pro-

tective pillars, the process of UCG may

represent the most optimal solution.Quantities of about 3.8 billion bitu-

minized marlon, that overlies the oil shale,

with about 4-5% organic matter, may also

be subject to special investigations, and

future time will show whether they can be

treated together or separately for the oil

shale.


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Documents

ISPITIVANJE MOGUĆNOSTI ISTOVREMENE EKSPLOATACIJE UGLJA I ULJNIH ŠKRILJACA U ALEKSINAČKOM BASENU