Ka Hana ʻana o ka Pauka Alumina ma ke ʻano he Kākoʻo Catalyst
I ke kūkākūkā ʻana i ka ʻoihana kemika, ʻoiai ke kahua o ka catalysis, nui nā mea e pili ana i ia mea. I kēia lā, ʻaʻole mākou e kamaʻilio e pili ana i kēlā mau ʻāpana metala hana kiʻekiʻe, akā, ʻo ka "hero unsong" i hoʻopoina pinepine ʻia akā pono loa - ka pauka alumina. Ua like ia me ke kia o ke kahua, a i ʻole ke kahua o kahi hale; pehea ka maikaʻi o ka hana ʻana o nā ʻāpana hana, ʻo kēlā mau "hōkū," e pili pono ana i ka maikaʻi o ke kūkulu ʻia ʻana o ke kahua.
I koʻu komo mua ʻana i kēia kahua, ua ʻike au he mea kupanaha—no ke ahaʻaluminakikoʻī? He mea kupanaha ʻole ia, no laila pehea lā i loaʻa ai iā ia kahi kūlana koʻikoʻi i ka ʻoihana kākoʻo catalyst? Ma hope mai, ma hope o ka hoʻolilo ʻana i kahi manawa lōʻihi me nā limahana akamai ma ka lab a me ka hale hana, ua hoʻomaopopo mālie wau. ʻAʻole ia ke koho "maikaʻi loa", akā ʻo ke koho "kaulike loa" i loaʻa ma waena o ka hana, ke kumukūʻai, a me ka hoʻohana pono. Ua like kēia me ke kūʻai ʻana i kaʻa; ʻaʻole pono mākou i ka mea wikiwiki loa, akā ʻo ia ka mea e kaulike ai i ka pono o ka wahie, ka hakahaka, ka lōʻihi, a me ke kumukūʻai. I ka ʻoihana lawe, ua like ka alumina me kēlā "all-rounder" - he mau nāwaliwali a me nā ikaika koʻikoʻi.
ʻO ka mea mua, pono mākou e hoʻomaikaʻi i kona ʻano "porous sponge"—ka ʻilikai nui a me ka hiki ke ulu kiʻekiʻe loa.
ʻO kēia ka ikaika nui opauka aluminaMai noʻonoʻo iā ia he palaoa paʻakikī a mānoanoa āu e hoʻohana ai ma ka home. Ma hope o ka hana kūikawā, ua piha ka loko o kahi mea lawe alumina me nā micropores a me nā kahawai ma ka nanoscale. Ua kapa ʻia kēia ʻano he "ʻāpana ʻili kikoʻī kiʻekiʻe."
I mea e hoʻohālikelike ai, hoʻokahi gram o ka pauka alumina kiʻekiʻe, inā e hoʻonui piha ʻia kona mau pores i loko, e hiki maʻalahi i kekahi mau haneli mika kūlike ma ka ʻili—ʻoi aku ka nui ma mua o ke kahua kinipōpō hīnaʻi! E noʻonoʻo i ka nui o nā mea hana catalytically (e like me ka platinum, palladium, a me ka nickel) hiki ke hoʻokipa ʻia i loko o ia "ʻāina" nui! Ua like ia me ka hāʻawi ʻana i nā mea hana me kahi "dormitory" nui loa, i hoʻolako maikaʻi ʻia, e ʻae ana iā lākou e hoʻopuehu like a pale i ka hui pū ʻana, a laila e hoʻonui i ko lākou ʻike a me ka pili ʻana me nā reactants. Hōʻoia kēia i ka pono catalytic.
Eia kekahi, hiki ke "hoʻopilikino ʻia" ke ʻano o ka pore o kēia "hupa." Ma ka hoʻoponopono ʻana i ke kaʻina hana hoʻomākaukau, hiki iā mākou ke kāohi i ka nui, ka hoʻolaha ʻana, a me ke ʻano o kona mau pores i kekahi ʻano, e like me ka lepo hoʻoheheʻe. He nui kekahi mau molekala reactant a koi i nā "puka" nui aʻe e komo ai; wikiwiki kekahi mau hopena a koi i nā pores pōkole e pale aku ai iā lākou mai ka nalowale ʻana i loko o kahi maze. Hiki i ke kākoʻo alumina ke hoʻokō pono i kēia mau "pono pilikino," kahi maʻalahi i kūlike ʻole me nā mea ʻē aʻe he nui.
ʻO ka lua, he mea kūpono ke haʻi ʻia kona "ʻano maikaʻi"—loaʻa iā ia ke kūpaʻa kemika maikaʻi loa a me ka ikaika mechanical.
ʻAʻole ʻoluʻolu loa ke kaiapuni kahi e noho ai nā mea hoʻouluulu. He pinepine ka mahana a me ke kaomi kiʻekiʻe, a i kekahi manawa pili pū kekahi i ka ʻike ʻana i nā kinoea ʻino. E noʻonoʻo inā he "pahuhopu palupalu" ke kākoʻo ponoʻī, e hiolo ana i loko o ʻelua lā i loko o ka reactor, a i ʻole e pane ana i ke kemika me nā mea hana a me nā mea hana - ʻaʻole anei e haunaele nā mea āpau?
ʻO ka pauka alumina, ma kēia ʻano, he "paʻa" kupaianaha. Mālama ia i kona ʻano kristal ʻoiai i nā mahana kiʻekiʻe, e kūʻē ana i ka hiolo ʻana, a ʻo kona mau waiwai kemika he "neutral," ʻaʻole maʻalahi ka pane ʻana me nā mea ʻē aʻe. Hōʻoia kēia i kahi ola catalyst lōʻihi, e mālama ana i nā hale hana i ka manawa downtime nui a me nā kumukūʻai hoʻololi.
Eia kekahi, e noʻonoʻo i ka ikaika mechanical. I loko o nā reactors ʻoihana, ʻaʻole waiho wale ʻia nā catalysts; pono pinepine lākou e kū i ka hopena o ke kahe ʻana o ka ea, ka friction ma waena o nā ʻāpana, a me ka hiolo ʻana i loko o kahi moena e neʻe ana. Inā lawa ʻole ka ikaika, e hiolo ia i ka pauka i ka wā e lawe ʻia ai, a i ʻole e lilo i lehu i ka wā e komo ai i loko o ka reactor—he aha ka catalysis hiki iā ia ke hoʻokō?ʻAluminanā kākoʻo, ma hope o ke kāwili ʻana a me ka calcination, e hoʻomohala i ka ikaika kiʻekiʻe e kū i kēia mau "hoʻoluhi," e hōʻoia ana i ka hana lōʻihi a paʻa o ka hāmeʻa hana. ʻO kēia ka manaʻo o nā limahana akamai i ka wā e ʻōlelo ai lākou "ua paʻa kēia mea hoʻoulu."
Eia kekahi, he kūpaʻa loa nō hoʻi—he ikaika loa kona mau ʻano ʻili.
ʻAʻole laumania ka ʻili o ka alumina. Loaʻa iā ia nā wahi waikawa a kumu paha. Loaʻa i kēia mau wahi nā mana catalytic no kekahi mau hopena. ʻOi aku ka mea nui, hiki iā lākou ke "launa pū" me ka metala hana i kākoʻo ʻia—kahi hanana a mākou e kapa nei he launa pū.
He nui nā pono o kēia launa pū ʻana. Ma kekahi ʻaoʻao, hana ia e like me ke "pili," e "pili pono" ana i nā ʻāpana metala i ke kākoʻo, e pale ana iā lākou mai ka neʻe ʻana, ka hōʻuluʻulu ʻana, a me ka ulu ʻana i nā mahana kiʻekiʻe (ua kapa ʻia kēia he sintering). Ke hana ʻia ka sintering, hāʻule nui ka hana catalytic. Ma kekahi ʻaoʻao, hiki iā ia ke hoʻololi i ke kūlana uila o nā ʻāpana metala, e hana maikaʻi ana iā lākou i nā hopena catalytic, e hoʻokō ana i ka hopena synergistic o "1+1>2".
ʻOiaʻiʻo, ʻaʻohe mea hemolele. ʻAʻole nele nā kākoʻo Alumina i nā hemahema. No ka laʻana, i nā wahi wela kiʻekiʻe loa me ka mahu wai, hiki ke hana i kahi "hoʻololi pae," e hoʻololi ana mai ke ʻano γ-ʻano ikaika loa i ke ʻano α-ʻano liʻiliʻi, e alakaʻi ana i ka hiolo ʻana o ka pore a me ka emi nui ʻana o ka ʻili. Ua like kēia me ke kalapona i hoʻāla ʻia i puhi ʻia i loko o ka graphite; ʻoiai he kalapona nō ia, ʻokoʻa loa kona hiki ke adsorption. No laila, ke hana nei nā mea noiʻi e hoʻomaikaʻi i kona kūpaʻa wela ma ka hoʻohui ʻana me nā mea ʻē aʻe (e like me ka silicon a me ka zirconium) a i ʻole e hoʻomohala i nā kaʻina hana hoʻomākaukau hou e hoʻonui i kona mau ikaika a hoʻemi i kona mau nāwaliwali.
No laila, ʻike ʻoe, aia i loko o kēia pauka keʻokeʻo maʻamau ka waiwai o ka ʻike. ʻAʻole ia he ʻenehana ʻeleʻele hiki ʻole ke hoʻomaopopo ʻia, akā ʻo ia ke ʻano o kēia mea, e hoʻoikaika ana no ke kaulike a me ka hoʻomaikaʻi ʻana i nā kikoʻī āpau, e kākoʻo ana i ka hapalua o ka ʻōnaehana catalytic ʻoihana hou. Mai ka hoʻomaʻemaʻe ʻana i ka ʻōpala kaʻa a hiki i ka haki ʻana a me ka hoʻoponopono hou ʻana i ka petroleum, a me ka synthesizing i nā mea maka kemika like ʻole, ʻike pinepine ʻia ka hana mālie o nā mea lawe alumina ma hope o nā hiʻohiʻona.
ʻAʻole ia e ʻālohilohi e like me nā metala makamae e like me ka platinum a i ʻole ka palladium, a ʻoi aku ka haʻahaʻa o kona kumukūʻai, akā ʻo kona hilinaʻi, ka lōʻihi, a me ke kumukūʻai kiʻekiʻe e lilo ia i kahua paʻa loa no nā noi ʻoihana nui. I ka manawa aʻe e lohe ai ʻoe e pili ana i kahi holomua i ka ʻenehana catalytic, e hāʻawi iā ia i kahi manamana lima noʻonoʻo, no ka mea, ʻo ka pauka alumina, ka mea kaulana ma hope o nā hiʻohiʻona, pono i kahi hapa nui o ka hōʻaiʻē no kēia hoʻokō.