Indlela Imithombo Ye-Geothermal Esebenza Futhi Efakwa Ngayo
Amandla okushisa komhlaba ayindlela yamandla avuselelekayo esebenzisa ukushisa okuvela emhlabeni. Emazweni amaningi, kufaka phakathi i-Indonesia, etholakala eduze kweRing of Fire, amandla okushisa komhlaba anamandla amakhulu okukhiqizwa kukagesi kanye nokusetshenziswa kokushisa okuqondile. Esinye sezingxenye ezibaluleke kakhulu ekusetshenzisweni kwamandla okushisa komhlaba umthombo wamanzi okushisa komhlaba, umgodi obholiwe obholiwe ukuze kutholakale uketshezi olushisayo (umusi kanye/noma amanzi ashisayo) ovela echibini elingaphansi komhlaba. Lesi sihloko sixoxa ngendlela umthombo wamanzi okushisa komhlaba osebenza ngayo kanye nezinyathelo ezijwayelekile zokufaka owodwa.
1. Uyini umthombo we-geothermal?
Umthombo we-geothermal uwumthombo obholwe wafinyelela ekujuleni okuthile ukuze ufinyelele indawo yokugcina amanzi ashisayo. Leli tangi liqukethe uketshezi olushisayo olucindezelwe, ingxube yesitimu, amanzi ashisayo, kanye namagesi angashisi (njenge-CO₂ kanye ne-H₂S ngamanani athile). Kunezinhlobo ezingaphezu kweyodwa zemithombo ye-geothermal; insimu ye-geothermal ngokuvamile iqukethe:
1. Umthombo wokukhiqiza: ugeleza uketshezi olushisayo luye phezulu ukuze lusetshenziswe.
2. Faka umthombo: buyisela amanzi ahlanganisiwe noma usawoti (amanzi ashisayo anokuqukethwe okuphezulu kwamaminerali) echibini ukuze ingcindezi ihlale izinzile futhi imvelo ivikeleke kangcono.
3. Ukuqapha imithombo: qapha ukucindezela, izinga lokushisa kanye nokuziphatha kwedamu.
Ngale nhlanganisela yemithombo, uhlelo lokushisa komhlaba lungasebenza ngendlela eqhubekayo, lugcine ibhalansi yamanzi futhi lwandise impilo yokusebenza kwensimu.
2. Indlela imithombo ye-geothermal esebenza ngayo
Indlela umthombo we-geothermal osebenza ngayo incike ezicini zedamu kanye nobuchwepheshe bokukhiqiza obusetshenziswayo. Kodwa-ke, isimiso esijwayelekile silandela lokhu:
a) Ukushisa kwe-Geothermal kwakheka futhi kugcinwe emathangini okugcina amanzi
Ukushisa kuvela ekujuleni koMhlaba, kungaba ngenxa yomsebenzi we-magma noma i-gradients yemvelo yokushisa. Amanzi angaphansi komhlaba awela phansi ayashiswa futhi abanjwe edwaleni elinezimbobo noma eliqhekekile, akha amachibi. Ukucindezela okuphezulu ekujuleni kuvumela uketshezi ukuthi lugcine amandla amaningi.
b) Uketshezi olushisayo lukhuphuka emthonjeni wokukhiqiza
Uma umthombo wokukhiqiza uvulwa, umehluko wokucindezela ubangela ukuthi uketshezi luye phezulu. Kwezinye izimo, uketshezi lungageleza ngokwalo (artesian) ngaphandle kwephampu. Ezinhlotsheni ezithile—ikakhulukazi ezinhlelweni ze-geothermal ezisezingeni eliphakathi—kungadingeka iphampu yomthombo.
c) Ukuhlukaniswa komusi namanzi (uma kudingeka)
Uma uketshezi oluphumayo luyingxube yomusi namanzi, kusetshenziswa isihlukanisi sobuso. Umusi uqondiswa ku-turbine, kuyilapho amanzi ashisayo (i-brine) angabuyiselwa emthonjeni wokujova noma asetshenziselwe ezinye izinjongo (njengokushisa, ukomisa, noma izinqubo zezimboni).
d) Ukuguqulwa kube ugesi noma ukushisa okuqondile
Izinhlelo ezintathu eziyinhloko zezitshalo zamandla kagesi ezisebenzisa i-geothermal yilezi:
– Umusi owomile: umusi owomile ujikeleza ngqo i-turbine.
– Umusi osheshayo: amanzi ashisayo acindezelwe “aphanyekwa” abe umusi ngomfutho ophansi; umusi uphendula i-turbine.
– Umjikelezo we-binary: Ukushisa okuvela kuketshezi lwe-geothermal kushisa uketshezi lwesibili olusebenzayo (isb., i-isobutane) ku-heat exchanger; uketshezi olusebenzayo luyahwamuka bese luphendula i-turbine. Lolu hlelo lufanele amazinga okushisa aphansi e-reservoir futhi luvame ukuba lu-close-loop, okuholela ekukhishweni okuphansi komoya.
e) Ukufakwa kabusha koketshezi echibini
Ngemva kokukhishwa kwamandla, uketshezi olusele luvame ukujovwa kabusha ngomthofu womjovo. Umjovo uyasiza:
- gcina ingcindezi ye-reservoir,
- ukunciphisa ingozi yokwehla komkhiqizo,
- ukunciphisa ukuchitheka kwamanzi amaminerali endaweni ezungezile,
– kusekela ukusimama kwesikhathi eside.
3. Izigaba zokufakwa kwemithombo yamanzi ashisayo
Ukufakwa kwemithombo yamanzi ashisayo kuyinqubo eyinkimbinkimbi ehilela izifundo ze-geological, ubunjiniyela bokubhoboza, ukuphepha, kanye nokuphathwa kwemvume nokuvikelwa kwemvelo. Izinyathelo ezijwayelekile yilezi ezilandelayo:
1) Izifundo zokuqala nezokuhlola
Ngaphambi kokumba, kwenziwa ucwaningo ukuze kutholakale izindawo ezingaba khona futhi kuncishiswe ingozi yezindleko eziphezulu ngenxa yokonakala kwemithombo. Lesi sigaba sihlanganisa:
– Izifundo ze-Geology: imephu yamadwala, izakhiwo zamaphutha, ukubonakaliswa kobuso (iziphethu ezishisayo, ama-fumarole).
– I-Geochemistry: ukuhlaziywa kokuqukethwe kwamanzi ashisayo ukuze kulinganiswe izinga lokushisa ledamu kanye nomsuka woketshezi.
– I-Geophysics: izindlela ze-magnetotelluric (MT), amandla adonsela phansi, ukuzamazama komhlaba, noma zokumelana nokumelana ukuze kudwetshwe izakhiwo ezingaphansi komhlaba.
– Ukukhetha indawo yomthombo: ukucabangela ukufinyelela, ukuma kwendawo, ukuphepha, kanye nokugcinwa kokushisa okungenzeka.
Imiphumela yokuhlola izonquma ukujula kwenhloso, indlela yokubhoboza (eqondile noma eqondile), kanye nomklamo wobuchwepheshe.
2) Ukunikeza ilayisense, i-AMDAL, kanye nokulungiselela indawo
Ngenxa yokuthi amaphrojekthi okushisa komhlaba makhulu futhi avame ukutholakala ezindaweni ezibucayi, kuyadingeka:
- ilayisensi ngokwemithethonqubo,
– izifundo zemvelo (isib. i-AMDAL),
- ukubonisana nomphakathi kanye nezinhlelo zokuphatha umphakathi.
Ensimini, kwenziwa ukuhlanzwa komhlaba okulinganiselwe, ukwakhiwa kwezindawo zokufaka amanzi emithonjeni, ukufinyelela emigwaqweni, kanye nohlelo lokukhipha amanzi ukuze kusingathwe amanzi emvula kanye nodaka lokumba.
3) Ukuhlanganiswa kwemishini nemishini
Imishini yokubhoboza esebenzisa umoya oshisayo ihlukile emithini kawoyela negesi ngezindlela eziningana, ikakhulukazi ngenxa yokushisa okuphezulu kanye namathuba okugqwala. Imishini ethwalwayo ihlanganisa:
- uhlelo lokufaka nokuphakamisa,
– iphampu yodaka,
– ipayipi lokubhoboza kanye ne-drill bit,
– imishini yokulawula imithombo (isivikelo sokuqhumisa/i-BOP),
– izinhlelo zokuphatha uketshezi, amathangi, kanye nezindawo zokuphepha.
4) Ukubhoboza isinyathelo ngesinyathelo (ukubhoboza kwesigaba)
Imithombo ye-geothermal ivame ukubholwa ngezigaba zokunciphisa ububanzi ngokujula:
– Ibhokisi lomqhubi: ipayipi lokuqala lokuqinisa ingxenye ephezulu yomhlabathi nokuvimbela ukudilika.
– Isembozo esingaphezulu: sivikela amanzi angajulile futhi sihlinzeka ngesivikelo sokuqala.
– Isikhala esiphakathi nendawo (uma kudingeka): kwezinye izindawo zamadwala ezingazinzile noma ezicindezelwe.
– Ibhokisi/i-liner yokukhiqiza: ibeka umugqa endaweni yokukhiqiza ukulawula ukugeleza koketshezi.
Ngesikhathi sokubhoboza, udaka lokubhoboza lusetshenziswa ukuphakamisa izingcezu zamatshe, ukuqinisa imbobo yomthombo, ukulawula ingcindezi, kanye nokupholisa i-drill bit. E-geothermal, izinselele ezengeziwe zifaka phakathi ukulahleka kokujikeleza kwegazi ngenxa yokuqhekeka kwamatshe kanye namazinga okushisa aphezulu athinta izakhiwo zodaka.
5) Ukufakwa kwekheyisi kanye nokufakwa kwesimende
Ngemva kokuba ingxenye ngayinye ibholiwe, kwenziwa i-casing kanye ne-cement. Ukufaka usimende kubalulekile ngoba kuhlose:
– bopha i-casing ekwakhekeni kwedwala,
– vimbela ukuvuza koketshezi phakathi kwezingqimba,
– thuthukisa ubuqotho bomthombo emazingeni okushisa aphezulu.
Izinto zikasimende ezisebenzisa ugesi ziklanyelwe ukuba zikwazi ukumelana nokushisa nokushisa ukuze zivimbele ukuqhekeka lapho umthombo udlula emjikelezweni wokushisa nokupholisa.
6) Ukulawula nokuphepha kwemithombo
Amandla okushisa komhlaba angakhiqiza umusi ocindezelwe kanye namagesi ayingozi njenge-H₂S. Ngakho-ke, izindinganiso zokuphepha ziqinile kakhulu, okuhlanganisa:
- Ukufakwa kwe-BOP,
- izinqubo zokulawula imithombo,
- ukuqapha igesi,
- ukusetshenziswa kwemishini yokuzivikela yomuntu siqu,
– uhlelo lokuphendula eziphuthumayo.
7) Ukuqedwa komthombo kanye nokuvuselelwa kwawo
Ngemva kokufinyelela umgomo, isigaba sokuqedwa senziwa kanje:
– ukufakwa kwe-wellhead kanye ne-valve yokuphepha,
– ukufakwa kwezimbobo noma ukuvulwa kwezindawo ezithile zokukhiqiza (kuye ngokuthi umklamo unjani),
– ukuvuselela (uma kudingeka), isibonelo ukuhlanza imithombo noma ukwelashwa ukuze kwandiswe ukugeleza koketshezi.
Ekushiseni komhlaba, ukuqedwa kumele kucabangele ukukala (ukuna kwamaminerali njenge-silica noma i-calcite) kanye nokugqwala.
8) Ukuhlolwa kokukhiqiza (ukuhlolwa kwemithombo)
Uma umthombo usubholiwe, awusetshenziswa unomphela ngokushesha. Kuyenziwa izivivinyo, ezifana nalezi:
- ukuhlolwa kokugeleza ukuze kulinganiswe izinga lokukhiqizwa komusi/amanzi,
– izinga lokushisa kanye nokulinganisa ingcindezi,
- ukuhlaziywa kwamakhemikhali koketshezi,
- ukuhlolwa kokuzinza kokugeleza kanye nokukwazi ukukala amandla.
Idatha yokuhlola inquma ukuthi umthombo ufanelekile yini ukukhiqizwa, udinga ukulungiswa, noma uhloselwe ukusetshenziswa njengomthombo wokujova.
9) Ukuhlanganiswa kwezakhiwo ezingaphezulu komhlaba
Uma umthombo ungena esigabeni sokusebenza, umthombo uxhunywa ku:
– amapayipi anezigaba ezimbili (amanzi anomusi) noma amapayipi anomusi,
- isihlukanisi kanye ne-scrubber,
– ijenereyitha (i-turbine, i-condenser, umbhoshongo wokupholisa),
– umugqa womjovo wokubuyisela.
Lonke inethiwekhi lenzelwe ukumelana namazinga okushisa aphezulu, ukucindezeleka, kanye nezimo ezigqwalisayo.
4. Izinselele ezinkulu ekufakweni kwemithombo yamanzi ashisayo
Ukufakwa kwemithombo yamanzi ashisayo kubhekene nezinselele ezingavamile, ezifana nalezi:
– Amazinga okushisa aphezulu kakhulu asheshisa ukuguguleka kwamathuluzi futhi athinte usimende/ikheyisi.
– Ukulahleka kokujikeleza kwegazi edwaleni eliqhekekile, okungandisa izindleko zokubhoboza nesikhathi.
– Ukukhula kanye nokugqwala okuthinta amapayipi kanye nemishini engaphezulu.
– Izingozi ze-H₂S kanye nokukhishwa kwegesi okudinga izinhlelo zokunciphisa nokuqapha.
– Ukufinyelela ezindaweni kuvame ukuba sezintabeni ngakho-ke ukuthuthwa kwempahla kunzima.
Ngakho-ke, ukwakheka komhlaba, izinto zokwakha, kanye nezinqubo zokusebenza kugcizelela kakhulu ukuthembeka kwesikhathi eside.
5. Isiphetho
Imithombo ye-geothermal iyisango eliyinhloko lokuvuna amandla e-geothermal: uketshezi olushisayo oluvela echibini luphakanyiswa ngemithombo yokukhiqiza, lucutshungulwe phezu komhlaba ukuze lukhiqize ugesi noma ukushisa okuqondile, bese lubuyiselwa ngaphansi komhlaba ngemithombo yokufaka ukuze kulondolozwe uhlelo oluzinzile noluzinzile. Ukufakwa kudinga uchungechunge lwezinyathelo, kusukela ekuhloleni nasekuvumeleni kuya ekubholeni nasekufakeni ikheyiji kanye nesamente, kuya ekuhlolweni kokukhiqiza kanye nokuhlanganiswa kwezikhungo zokukhiqiza. Ngokuhlela ngokucophelela kanye nezindinganiso zokuphepha eziphakeme, imithombo ye-geothermal ingaba ingqalasizinda ehlakaniphile yokusekela ukuguquka kwamandla ahlanzekile kanye nokuphepha kwamandla kazwelonke.
Uma ufisa, ngingalungisa lesi sihloko sibe sezobuchwepheshe kakhulu (isib. ukwengeza amapharamitha okufaka izikhala, izinhlobo zesimende, kanye nezinhlelo ze-wellhead) noma sithandwe kakhulu ngabafundi abavamile, kanye nokuqinisekisa ukuthi inani lamagama licishe libe amagama ayi-1000 njengoba kudingeka.
