Te Mahi a te Tukanga Tauhohenga a Haber Bosch
Ko te tukanga Haber-Bosch tētahi o ngā kitenga tino nui i roto i te hītori o te matū ahumahi nā te mea ka taea e te tangata te whakaputa haukini (NH₃) i runga i te tauine nui mai i ngā hau e rua e nui ana i te taiao: te hauota (N₂) mai i te rangi me te hauwai (H₂), e whiwhihia ana i te nuinga o te wā mai i te hau maori, i ētahi atu puna rānei. Kātahi ka noho te haukini hei rauemi mata matua mō ngā maniua hauota pēnei i te urea me te ammonium nitrate, e whai wāhi nui ana ki te whakapiki i te hua ahuwhenua o te ao. Ki te kore tēnei tukanga, tera pea ka iti ake te wātea o te kai o te ao.
Papamuri: he aha i uaua ai te "hopu" i te hauota?
Ahakoa kei roto i te hau te 78% o te hauota, he tino pumau te hau N₂ nā te mea e herea ana ōna ngota hauota e rua e te hononga kaha toru (N≡N). Ko tēnei hononga te mea e "ārai" ai te hauota ki te tauhohe. Me hiahia ngā tipu ki te hauota hei hanga pūmua me ngā waikawa karihi, engari kāore e taea e rātou te whakamahi tika i te N₂ mai i te hau. I te nuinga o te wā, ka whakapumautia te hauota e ētahi huakita, e te uira rānei, engari kāore te tere o ēnei tukanga taiao e ranea hei whakatutuki i ngā hiahia o te ahuwhenua hou. Koinei te wāhi e uru mai ai a Haber-Bosch: te whakarato i tētahi huarahi ki te "whakahau" i te hauota ki te tauhohe mā roto i ngā āhuatanga hangarau me ngā whakakorikori.
Tauhohenga matua: mai i te hauota me te hauwai ki te haukini
Ko te whārite matua o te tauhohenga o te tukanga Haber-Bosch ko:
N₂(g) + 3H₂(g) ⇌ 2NH₃(g) + wera
Ka taea te huri i tēnei tauhohenga (ka taea te haere i ngā taha e rua) ā, ka puta he wera (ka puta he wera). Ko te tikanga tēnei he pai ake te hanganga o te haukini i ngā pāmahana iti iho i runga i te mātāpono taurite, engari i ngā pāmahana tino iti ka tino puhoi te haere o te tauhohenga. Nō reira, me kimi e ngā tukanga ahumahi he taurite i waenga i te tere tauhohenga me te hua taurite.
Ngā wāhanga matua o te tukanga Haber-Bosch
I te nuinga o te wā, he maha ngā wāhanga o te tukanga ahumahi a Haber-Bosch: te whakarato rauemi mata (H₂ me te N₂), te purenga, te kōpeketanga, te tauhohenga hanga me te whakakorikori, te wehenga o te haukini, me te hangarua o te hau kāore i tauhohe.
1. Ngā pūtake me te whakaputanga o te hauwai (H₂)
Ko te hauwai mō te tukanga Haber-Bosch i te nuinga o te wā ka puta mai i te whakahounga o te hau māori (methane, CH₄). Ko ngā mahi ko:
– Te whakahounga o te methane mamaoa (SMR): ka tauhohe te methane ki te mamaoa wai i ngā pāmahana teitei hei whakaputa i te ranunga hau (syngas) kei roto ko te H₂, te CO, me te CO₂.
– Tauhohenga nekehanga wai-hau: Kātahi ka tauhohe anō te CO ki te mamaoa wai hei whakaputa i te CO₂ me te tāpiri i te H₂.
Hei whakamutunga, ka wehea te CO₂, ā, ka purea te hauwai. I roto i ētahi tipu, ka taea hoki te whakaputa hauwai mai i te hikohiko wai, inā koa kei te wātea te hiko whakahou, ahakoa he nui ake te utu ohanga o tēnei i te hau māori.
2. Te tango i te hauota (N₂) mai i te rangi
Ko te tikanga, ka tangohia te hauota mā te wehenga hau mā te whakamahi i ngā waeine cryogenic (whakamatao ki ngā pāmahana tino iti) me ētahi atu hangarau pēnei i te adsorption pressure swing (PSA). Ko te whāinga kia whiwhi hauota parakore teitei, nā te mea ka taea e ētahi poke te whakapōrearea i te whakakorikori me te whakararuraru i te tauhohenga.
3. Te purenga hau: te tango i ngā "paitini" whakakorikori
He tino tairongo ngā whakakorikori e whakamahia ana i roto i te Haber-Bosch (he rino te nuinga) ki ngā matū pēnei i te whanariki (S), te hauota waro (CO), me ētahi atu poke. Nō reira, me pure te hau whāngai:
– Ka tangohia ngā matū whanariki mā te whakamahi i ngā mea mimiti motuhake.
– Ka tukatukahia te CO me te CO₂ mā roto i ngā tauhohenga matū (nekehanga, methanation) mā te wehenga ā-tinana/matū rānei.
– Ka whakaitihia hoki te makuku (H₂O) kia kore ai e whakararuraru i te tukanga.
He mea tino nui tēnei purenga nā te mea he nui te whakawhirinaki o te whai huatanga o te tipu me te roa o te ora o te whakakorikori ki te ma o te hau.
4. Kōpeketanga: te whakanui ake i te pēhanga hei neke i te taurite
He iti ake ngā mole hau e puta mai ana i te tauhohenga (mai i te 4 mole hau ki te 2 mole hau). E ai ki te mātāpono a Le Chatelier, ka nekehia te taurite e te pēhanga teitei ki te hua (NH₃). Nō reira, ka pēhia te ranunga o te N₂ me te H₂ ki ngā pēhanga teitei, he maha ngā wā i roto i ngā rau o ngā āhuarangi i roto i ngā mahi ahumahi hou (tērā pea ka rerekē te tau tika i runga i te hoahoa o te tipu).
Heoi, nā te pēhanga teitei, he nui te hiahia mō te pūngao mō te compressor, nō reira me arotau te tipu i waenga i te hua haukini me ngā utu pūngao.
5. Tauhohenga Hanga: te tūranga o te whakakorikori me te pāmahana whakahaere
I roto i te tauhohenga, ka tukuna he ranunga o te N₂ me te H₂ ki runga i tētahi whakakorikori. Ko te whakakorikori matarohia mō te tukanga Haber-Bosch ko te rino (Fe) me ngā kaiwhakatairanga pērā i te waikura pāhare pāporo (K₂O), te waikura konumohe (Al₂O₃), me te waikura konupūmā (CaO). Ka āwhina ngā kaiwhakatairanga ki te whakanui ake i te mahi me te pumau o te whakakorikori.
Ko te pāmahana tauhohenga ka whakatakotoria kia teitei kia tika ai te tere o te tauhohenga . Heoi, nā te mea he werawera te tauhohenga hanganga haukini, ka whakaitihia te hua taurite e ngā pāmahana tino tiketike. Nō reira, ka whakatakotoria te pāmahana ki roto i tētahi awhe taurite e āhei ai te tauhohenga kia tere tonu te haere me te whakaputa hua pai tonu.
I te taumata ngota ngota, ko te mahi a ngā whakakorikori mā te:
– Te wāwāhi i ngā here N≡N i runga i te mata o te whakakorikori (koinei te taahiraa tino uaua).
– Ka mimiti i te H₂, ka wawahi i a ia hei ngota H.
– Ka āwhina i te hanganga āta o ngā hononga N–H kia hangaia rā anō te NH₃.
– Te tuku i te NH₃ mai i te mata o te whakakorikori kia taea ai te whakamahi anō i ngā pae hohe.
6. Te whakamatao me te whakatōtō: te wehewehe i te haukini mai i te hau
I muri i te putanga mai i te tauhohenga, kei roto i te ranunga hau te NH₃ me te N₂ me te H₂ kāore anō kia tauhohe. Kātahi ka whakamataohia tēnei ranunga. Ka ngāwari te waikura o te haukini i raro i ētahi āhuatanga, ka taea ai te wehewehe mā te whakatōtō hei haukini wai.
He tino whai hua tēnei wehenga e ahu mai ana i te hauhautanga nā te mea:
– Te kimi i te hua matua me te whai hua
– Ka akiaki i te tauhohenga kia haere tonu (ka tangohia ngā hua, ka panaia te taurite ki ngā hua)
7. Te hangarua hau: ka whakapiki i te whai huatanga whānui
Kāore e hurihia katoatia te N₂ me te H₂ ki te NH₃ i roto i te kotahi haere i roto i te tauhohenga. Nō reira, ko te hau e toe ana ka whakahokia anō ki roto i te tauhohenga i muri i te wehenga mai i te haukini. Mā te hangarua ka nui ake te tere hurihanga whānui o te tukanga, ā, ka pai ake te whakamahinga o ngā rauemi mata.
I taua wā anō, ka taea te "whakakore" i tētahi wāhanga iti o te hau hei ārai i te kohikohinga o ngā mea kore e taea te whakamahi pērā i te argon e haria ana mai i te rangi.
Ngā āhuatanga e pā ana ki ngā hua o te tukanga
E toru ngā āhuatanga matua e kōrerohia tonutia ana i roto i te Haber-Bosch:
1. Pēhanga: ka nui ake te pēhanga, ka nui ake te ia o te whakaputa NH₃.
2. Pāmahana: ka tautokona e ngā pāmahana iti te taurite, engari ka tere ake te tere o te tauhohenga e ngā pāmahana teitei.
3. Whakakorikori: ka whakateretere i te whakatutukitanga o te taurite me te kore e whakarerekē i te tūranga taurite tonu.
Ka whiriwhiria e ngā ahumahi ngā tikanga whakahaere tino pai e whai whakaaro ana ki te ōhanga, te haumaru, te whai hua o te pūngao, me te roa o ngā taputapu.
Ngā pānga me ngā wero o ēnei rā
He mea tino nui te tukanga Haber-Bosch ki te ahuwhenua, engari he wero taiao anō hoki. Ko te whakaputa hauwai mai i te hau maori ka puta he tukunga CO₂. Nō reira, he nui ngā rangahau hou e aro ana ki:
– Hauwai "kakariki" mai i te hiko wai e hangai ana ki te pūngao whakahou
– Te hopu me te rokiroki waro (CCS) i roto i ngā tipu haukini
– Te whakawhanake i ngā whakakorikori hou kia taea ai ngā tauhohenga te puta i ngā pēhanga, i ngā pāmahana rānei iti iho
Ko te whāinga o ēnei mahi he pupuri i ngā painga nui o te haukini—ina koa hei tongi—me te whakaiti i tōna tapuwae waro.
Whakamutunga
Ko te tukanga Haber-Bosch he raupapa o ngā mahi ahumahi i hangaia hei wikitoria i te pumau o te hauota i te rangi, hei whakaputa nui hoki i te haukini. Ko te tikanga he tauhohenga o te N₂ me te H₂ e whakahaerehia ana e te whakakorikori, i arotauhia mā te pēhanga teitei, ngā pāmahana kua whakaitihia, te purenga hau, me te pūnaha wehewehe me te hangarua. Ko te hua ko te whakaputanga o te haukini, te pou tuara o ngā maniua hou, me te turanga nui mō te haumarutanga kai o te ao. Ko te wero matua mō te heke mai o tēnei tukanga ko te hanga kia pai ake te taiao mā roto i ngā puna hauwai iti-tukunga me te whakapai ake i te whai huatanga o te pūngao.
