Ib qho teeb meem ceev yog ib puag ncig muaj kuab paug thiab siv hluav taws xob tsawg ntawm cov organic keeb kwm. Ib txoj hauv kev zoo los daws cov teeb meem no yog siv hydrogen ua lub zog. Hauv tsab xov xwm peb yuav xav txog qhov teeb meem ntawm hydrogen combustion, qhov kub thiab txias ntawm cov txheej txheem no.
hydrogen yog dab tsi?
Ua ntej xav txog cov lus nug ntawm dab tsi yog qhov kub thiab txias ntawm hydrogen, nws yuav tsum nco ntsoov tias cov khoom no yog dab tsi.
Hydrogen yog cov khoom siv hluav taws xob zoo tshaj plaws, suav nrog tsuas yog ib qho proton thiab ib qho hluav taws xob. Nyob rau hauv tej yam kev mob (siab 1 atm., kub 0 o C) nws yog tam sim no nyob rau hauv lub gaseous xeev. Nws molecule (H2) yog tsim los ntawm 2 atoms ntawm cov tshuaj no. Hydrogen yog 3rd feem ntau cov khoom nyob rau hauv peb ntiaj chaw, thiab 1st nyob rau hauv lub ntiaj teb no (kwv yees li 90% ntawm tag nrho cov teeb meem).
Hydrogen gas (H2)odorless, tasteless thiab tsis muaj xim. Nws tsis yog tshuaj lom, txawm li cas los xij, thaum nws cov ntsiab lus hauv huab cua yog ob peb feem pua, ces tus neeg yuav hnov tsw vim tsis muaj oxygen.
Nws xav paub tias txawm hais tias los ntawm kev tshuaj ntsuam xyuas, tag nrho H 2 molecules zoo ib yam, lawv lub cev muaj zog sib txawv me ntsis. Nws yog txhua yam hais txog kev taw qhia ntawm lub tshuab hluav taws xob (lawv yog lub luag haujlwm rau qhov pom ntawm lub sijhawm sib nqus), uas tuaj yeem ua rau tib lub sijhawm thiab antiparallel, xws li cov molecule hu ua ortho- thiab parahydrogen, feem.
Combustion tshuaj tiv thaiv
Xav txog cov lus nug ntawm qhov kub thiab txias ntawm hydrogen nrog oxygen, peb nthuav tawm cov tshuaj tiv thaiv tshuaj uas piav qhia txog cov txheej txheem no: 2H2 + O 2=> 2H2O. Ntawd yog, 3 molecules koom nrog cov tshuaj tiv thaiv (ob lub hydrogen thiab ib qho oxygen), thiab cov khoom yog ob lub dej molecules. Cov tshuaj tiv thaiv no piav qhia txog kev sib xyaw ntawm cov tshuaj lom neeg, thiab nws tuaj yeem txiav txim siab tias tom qab nws dhau mus, tsuas yog cov dej ntshiab xwb, uas tsis ua phem rau ib puag ncig, raws li tshwm sim thaum lub sij hawm combustion ntawm fossil fuels (roj av, cawv).
Ntawm qhov tod tes, qhov tshuaj tiv thaiv no yog exothermic, uas yog, ntxiv rau dej, nws tso tawm qee qhov cua sov uas tuaj yeem siv los tsav tsheb thiab foob pob hluav taws, nrog rau hloov mus rau lwm qhov chaw ntawm lub zog, xws li raws li hluav taws xob.
Mechanism ntawm cov txheej txheem hydrogen combustion
Piav yav dhau loskab lus tshuaj tiv thaiv yog paub rau txhua tus menyuam kawm ntawv theem siab, tab sis nws yog ib qho lus piav qhia txog cov txheej txheem uas tshwm sim hauv qhov tseeb. Nco ntsoov tias kom txog rau thaum nruab nrab ntawm lub xyoo pua xeem, noob neej tsis paub yuav ua li cas hydrogen hlawv nyob rau hauv cov huab cua, thiab nyob rau hauv 1956 lub Nobel nqi zog nyob rau hauv Chemistry tau muab tsub rau nws txoj kev kawm.
Qhov tseeb, yog O2 thiab H2 molecules sib tsoo, yuav tsis muaj qhov tshwm sim. Ob qho molecules yog qhov ruaj khov heev. Txhawm rau combustion tshwm sim thiab dej los tsim, cov dawb radicals yuav tsum muaj. Tshwj xeeb, H, O atoms thiab OH pawg. Cov hauv qab no yog ib ntu ntawm cov tshuaj tiv thaiv uas tshwm sim thaum hydrogen hlawv:
- H + O2=> OH + O;
- OH + H2 => H2O + H;
- O + H2=OH + H.
Koj pom dab tsi los ntawm cov tshuaj tiv thaiv no? Thaum hydrogen hlawv, dej tsim, yog, yog lawm, tab sis nws tsuas yog tshwm sim thaum ib pab pawg ntawm ob OH atoms ntsib ib H2 molecule. Tsis tas li ntawd, tag nrho cov kev tshwm sim tshwm sim nrog kev tsim cov dawb radicals, uas txhais tau hais tias cov txheej txheem ntawm nws tus kheej-sustaining combustion pib.
Yog li tus yuam sij rau kev pib cov tshuaj tiv thaiv no yog tsim cov radicals. Lawv tshwm sim yog tias koj nqa qhov sib tw rau qhov sib xyaw oxygen-hydrogen, lossis yog tias koj ua kom sov qhov sib tov saum toj no qhov kub thiab txias.
pib cov tshuaj tiv thaiv
Raws li tau sau tseg, muaj ob txoj hauv kev ua qhov no:
- Kev pab ntawm lub txim uas yuav tsum tsuas yog 0,02mj ua. Qhov no yog tus nqi zog me me, rau kev sib piv, cia peb hais tias tus nqi zoo sib xws rau cov roj av sib xyaw yog 0.24 mJ, thiab rau methane - 0.29 mJ. Raws li lub siab txo qis, cov tshuaj tiv thaiv pib lub zog nce. Yog li, ntawm 2 kPa, nws twb yog 0.56 mJ. Txawm li cas los xij, cov no yog cov txiaj ntsig me me, yog li cov sib xyaw hydrogen-oxygen suav tias yog cov nplaim taws heev.
- Nrog kev pab ntawm qhov kub thiab txias. Ntawd yog, cov pa oxygen-hydrogen sib tov tsuas tuaj yeem ua kom sov, thiab siab dua qhov kub thiab txias nws yuav ua rau nws tus kheej. Thaum qhov no tshwm sim nyob ntawm qhov siab thiab feem pua ntawm cov pa roj. Nyob rau hauv ib tug ntau yam ntawm concentrations ntawm atmospheric siab, cov spontaneous combustion cov tshuaj tiv thaiv tshwm sim ntawm kub siab tshaj 773-850 K, uas yog, saum toj no 500-577 o C. Cov no yog cov nqi siab heev piv rau cov roj av sib tov, uas pib spontaneously ignite twb kub hauv qab 300 o C.
% ntawm cov pa roj hauv qhov sib tov sib xyaw
Hais txog qhov kub ntawm hydrogen combustion nyob rau hauv huab cua, nws yuav tsum tau muab sau tseg tias tsis yog txhua txhua sib tov ntawm cov gases yuav nkag mus rau hauv tus txheej txheem raws li xav txog. Nws tau raug sim tsim tias yog tias cov pa oxygen tsawg dua 6% los ntawm qhov ntim, lossis yog tias cov nyiaj hydrogen tsawg dua 4% los ntawm ntim, ces tsis muaj qhov tshwm sim tshwm sim. Txawm li cas los xij, cov kev txwv ntawm lub hav zoov ntawm qhov sib tov sib xyaw yog qhov dav heev. Rau huab cua, qhov feem pua ntawm hydrogen tuaj yeem nyob ntawm 4.1% txog 74.8%. Nco ntsoov tias tus nqi siab tsuas yog sib npaug rau qhov tsawg kawg nkaus rau oxygen.
Yogxav txog qhov sib xyaw ntawm cov pa-hydrogen ntshiab, ces cov kev txwv tseem dav dua ntawm no: 4, 1-94%.
Kev txo qis ntawm cov pa roj ua rau txo qis hauv cov kev txwv tshwj xeeb (qhov txwv qis dua, qhov siab poob qis).
Nws tseem ceeb heev kom nkag siab tias thaum lub sij hawm combustion ntawm hydrogen nyob rau hauv huab cua (oxygen), qhov tshwm sim cov tshuaj tiv thaiv cov khoom (dej) ua rau kom ib tug txo nyob rau hauv cov concentration ntawm reagents, uas yuav ua rau kom tshem tawm cov tshuaj..
Kev nyab xeeb kev nyab xeeb
Qhov no yog ib qho tseem ceeb ntawm cov khoom sib tov sib xyaw, vim tias nws tso cai rau koj los txiav txim seb cov tshuaj tiv thaiv nyob twj ywm thiab tswj tau, lossis cov txheej txheem tawg. Dab tsi txiav txim siab qhov kub hnyiab? Tau kawg, ntawm qhov concentration ntawm reagents, nyob rau hauv siab, thiab kuj nyob rau ntawm lub zog ntawm "noob".
Hmoov tsis zoo, hydrogen nyob rau hauv ntau qhov ntau ntawm qhov muaj peev xwm ua rau tawg tawg. Cov duab hauv qab no tau muab rau hauv cov ntaub ntawv: 18.5-59% hydrogen hauv huab cua sib tov. Ntxiv mus, ntawm cov npoo ntawm qhov kev txwv no, raws li qhov tshwm sim ntawm detonation, lub zog loj tshaj plaws ntawm ib chav tsev ntim tau tso tawm.
Qhov cim ntawm kev sib xyaw ua ke nthuav tawm qhov teeb meem loj rau kev siv cov tshuaj tiv thaiv no los tswj lub zog.
Cov tshuaj tiv thaiv kub hnyiab
Tam sim no peb los ncaj qha rau cov lus teb rau lo lus nug, dab tsi yog qhov kub ntawm hydrogen combustion. Nws yog 2321 K lossis 2048 o C rau kev sib xyaw nrog 19.6% H2. Ntawd yog, combustion kub ntawm hydrogen hauv huab cua yog siab dua2000 oC (rau lwm qhov ntau nws tuaj yeem ncav cuag 2500 o C), thiab piv rau cov roj av sib xyaw, qhov no yog ib qho loj heev (rau roj av txog 800 o C). Yog tias koj hlawv hydrogen hauv cov pa ntshiab, cov nplaim taws kub yuav siab dua (txog 2800 o C).
Cov nplaim taws kub hnyiab no nthuav tawm lwm qhov teeb meem hauv kev siv cov tshuaj tiv thaiv no los ua lub zog, vim tam sim no tsis muaj cov alloys uas tuaj yeem ua haujlwm tau ntev hauv cov xwm txheej hnyav.
Tau kawg, qhov teeb meem no daws tau los ntawm kev siv lub tshuab ua kom txias zoo rau lub chamber qhov twg hydrogen combustion tshwm sim.
Tus nqi tso tawm
Raws li ib feem ntawm cov lus nug ntawm qhov kub thiab txias ntawm hydrogen, nws kuj tseem nthuav qhia cov ntaub ntawv ntawm lub zog uas tau tso tawm thaum lub sijhawm cov tshuaj tiv thaiv no. Rau cov xwm txheej sib txawv thiab cov khoom sib xyaw ntawm cov sib tov sib xyaw, cov txiaj ntsig ntawm 119 MJ / kg txog 141 MJ / kg tau txais. Kom nkag siab tias qhov no ntau npaum li cas, peb nco ntsoov tias tus nqi zoo sib xws rau cov roj av sib xyaw yog kwv yees li 40 MJ / kg.
Lub zog tawm los ntawm hydrogen sib tov yog ntau dua li cov roj av, uas yog ib qho ntxiv rau nws siv los ua roj rau sab hauv combustion engines. Txawm li cas los xij, tsis yog txhua yam yooj yim heev ntawm no ib yam nkaus. Nws yog txhua yam hais txog qhov ceev ntawm hydrogen, nws qis dhau ntawm atmospheric siab. Yog li, 1 m3 ntawm cov roj no hnyav tsuas yog 90 grams. Yog koj hlawv no 1 m3 H2, ces 10-11 MJ cua sov yuav tawm, uas twb 4 zaug tsawg dua thaum twg hlawv 1 kg roj av (tsuas tshaj li 1 litre).
Cov duab qhia tau hais tias txhawm rau siv cov tshuaj tiv thaiv hydrogen combustion, nws yuav tsum tau kawm yuav ua li cas khaws cov roj no hauv lub tog raj kheej siab, uas twb tsim teeb meem ntxiv, ob qho tib si ntawm kev siv tshuab thiab kev nyab xeeb.
Kev siv cov hydrogen combustible sib tov hauv tshuab: teeb meem
Nws yuav tsum tau hais tam sim ntawd tias tam sim no cov hydrogen combustible sib tov twb tau siv nyob rau hauv qee qhov chaw ntawm tib neeg kev ua ub no. Piv txwv li, ua ib qho roj ntxiv rau qhov chaw foob pob hluav taws, ua qhov chaw tsim hluav taws xob hluav taws xob, nrog rau hauv cov qauv kev sim ntawm cov tsheb niaj hnub. Txawm li cas los xij, qhov ntsuas ntawm daim ntawv thov no yog minuscule piv rau cov fossil fuels thiab feem ntau sim hauv qhov xwm txheej. Yog vim li cas rau qhov no tsis yog tsuas yog qhov nyuaj ntawm kev tswj cov combustion cov tshuaj tiv thaiv nws tus kheej, tab sis kuj nyob rau hauv lub cia, tsheb thauj mus los thiab extraction ntawm H2.
Hydrogen hauv ntiaj teb xyaum tsis muaj nyob hauv nws daim ntawv ntshiab, yog li nws yuav tsum tau txais los ntawm ntau lub tebchaw. Piv txwv li, los ntawm dej. Qhov no yog ib txoj kev nrov nrov tam sim no, uas yog ua los ntawm kev hla hluav taws xob los ntawm H2O. Qhov teeb meem tag nrho yog qhov no siv zog ntau dua li tau txais los ntawm kev hlawv H2.
Lwm qhov teeb meem tseem ceeb yog kev thauj mus los thiab khaws cia ntawm hydrogen. Qhov tseeb yog tias cov roj no, vim qhov me me ntawm nws cov molecules, muaj peev xwm "yav tawm" los ntawm ib qho twg.ntim. Tsis tas li ntawd, nkag mus rau hauv cov hlau lattice ntawm alloys, nws ua rau lawv embrittlement. Yog li, txoj hauv kev zoo tshaj plaws los khaws H2 yog siv cov pa roj carbon atom uas tuaj yeem khi cov roj "elusive" gas.
Yog li, kev siv hydrogen ua roj rau ntawm qhov ntau lossis tsawg dua qhov loj tsuas yog siv tau yog "kho" hluav taws xob (piv txwv li, hloov cua thiab hnub ci zog rau hauv hydrogen siv dej electrolysis), los yog koj kawm xa H2 los ntawm qhov chaw (qhov twg muaj ntau) rau lub ntiaj teb.
