Cov pa roj carbon activated muaj cov qauv tsim pore heev thiab thaj chaw tshwj xeeb loj, yog li nws muaj qhov muaj zog adsorption, ua ke nrog cov pa roj carbon activated muaj ntau cov pa oxygen- muaj cov pab pawg ua haujlwm, yog li nws yog ib qho zoo heev adsorption, catalyst thiab catalyst cab kuj.
1. Lub hauv paus ntsiab lus ntawm activated carbon desulfurization
Lub adsorption ntawmqhib carbon for SO2 includes physical adsorption and chemical adsorption. When there is no water vapor and oxygen in the flue gas, physical adsorption mainly occurs, and the adsorption amount is small. When the flue gas contains sufficient water vapor and oxygen, activated carbon flue gas desulfurization is a process of both chemical adsorption and physical adsorption. Physical adsorption first occurs, and then catalytic oxidation of SO2 adsorbed on the surface of activated carbon to H2 SO4 in the presence of water and oxygen.
2. Activated carbon desulfurization cov txheej txheem tshwm sim nyob rau hauv lub xub ntiag ntawm H2O
Activated carbon flue gas desulphurization txawv ntawm lwm cov tshuab flue gas desulphurization. Nws yog ib qho kev siv tshuab raws li ib txwm siv microporous adsorption txoj kev xav. Txawm li cas los xij, cov txheej txheem adsorption no txawv heev los ntawm kev siv tshuab adsorption dej purification, vim nws koom nrog ntau -cov khoom siv adsorption huab hwm coj hloov pauv, yog li nws cov txheej txheem adsorption nyuaj heev. Nyob rau hauv lub xub ntiag ntawm dej, nyob rau hauv lub ze ntawm lub activated carbon, nto, qhov, loj pore thiab micro qhov, tag nrho cov muaj peev xwm tsim dej, chav, SO2, SO2-3, SO2-4, thiab lwm yam khoom. ntawm cov complex sib tov, muaj cov molecules, los yog ions thiab nws cov kom muaj nuj nqis, los yog muaj peev xwm txhawb kev txhim kho cov kev ua tau zoo ntawm cov adsorption, los yog muaj peev xwm activated carbon adsorption. Kev koom tes ntawm H2O hauv paus hloov pauv cov tshuaj tiv thaiv ntawm SO2 ntawm cov pa roj carbon monoxide, thiab muaj ntau qhov kev xav txog cov txheej txheem tshuaj tiv thaiv. Lizzio, Mochida, Cazorla-Amoros et al. ntseeg tias SO2 thiab O2 sib tw rau cov chaw nquag. Ntawm peb qhov ua tau oxidation tshwm sim, tsuas yog cov qauv hauv qab no tuaj yeem ua tau zoo: C -- SO2 ntxiv rau O2 ntxiv rau C -- SO3 ntxiv rau C -- O, uas yog, tsuas yog gaseous oxygen tau React nrog adsorbed SO2.
Tamura ntseeg tias H2O, SO2 thiab O2 molecules tuaj yeem nqus tau los ntawm cov pa roj carbon activated. Tsuav yog muaj qhov ze txaus nyob nruab nrab ntawm lawv thiab ib qho kev teeb tsa spatial, lawv tuaj yeem cuam tshuam ncaj qha rau ib leeg thiab thaum kawg tsim H2 SO4. Hauv cov qauv theoretical no, qhov sib npaug oxidation yog C -- SO2 ntxiv rau C -- OC -- SO3 ntxiv rau C.
Zawadzki et al. believed that the participation of H2O changed the reaction mechanism of SO2 on the carbon surface, and the oxidation reaction could not be carried out in the absence of H2O. In the presence of H2O, the pyranone functional groups and delocalized π electrons on the surface of activated carbon react with H2O molecules to generate H2O2, which can oxidize THE H2 SO3 formed after SO2 is dissolved in water to H2 SO4.
We believe that in the presence of water, the number of effective adsorption sites is not determined by the volume and number of micropores, and the micropore filling theory is not suitable for activated carbon desulfurization with water elution, Tamura mechanism and Lizzio theory are not suitable for this technology. Zawadzki's theoretical analysis is a reasonable explanation. The surface of activated carbon should follow the following equation: SO2 ·H2O plus H2O2 2H plus -- SO2-4 plus H2O.
3. Lub hauv paus ntsiab lus ntawm nitrogen tshem tawm los ntawm activated carbon
Kev siv tshuab ua kom carbon denitrification tuaj yeem muab faib ua txoj hauv kev adsorption, NH3 xaiv catalytic txo txoj kev thiab cov txheej txheem kub carbon txo. Txoj kev adsorption siv cov qauv microporous thiab cov pab pawg ua haujlwm ntawm cov pa roj carbon activated rau adsorb NOx, thiab oxidizes NO nrog tsawg reactivity rau NO2 nrog siab reactivity. Ntawm cov txheej txheem ntawm activated carbon adsorption NOx, tseem muaj qhov sib txawv loj ntawm cov kws tshawb fawb. NH3 xaiv catalytic txo txoj kev siv cov pa roj carbon activated adsorb NOx los txo qhov ua kom lub zog ntawm cov tshuaj tiv thaiv ntawm NOx thiab NH3 thiab txhim kho qhov kev siv ntawm NH3. Kev txo cov pa roj carbon ntau yog siv cov pa roj carbon thiab NOx cov tshuaj tiv thaiv ntawm qhov kub thiab txias los tsim CO2 thiab N2, qhov kom zoo dua yog tias tsis muaj qhov xav tau catalyst, cov khoom carbon yog pheej yig, qhov chaw dav, cov cua sov tsim los ntawm cov tshuaj tiv thaiv tuaj yeem rov ua dua. Txawm li cas los xij, kev tshawb fawb kinetic qhia tau hais tias cov tshuaj tiv thaiv ntawm O2 thiab carbon yog ua ntej tshaj ntawm NOx thiab carbon, yog li muaj O2 nyob rau hauv flue gas ua rau kom cov pa roj carbon ntau.
Cov txiaj ntsig tau pom tias qhov adsorption ntawm SO2 ntawm cov pa roj carbon activated feem ntau yog cov tshuaj adsorption, thiab kev ua haujlwm desulfurization ntau dua 96 feem pua nrog cov sib xyaw ntawm siab -purity SO2, huab cua thiab dej vapor los simulate cov roj flue tiag tiag. Kev sib xyaw ntawm NOx siab purity, huab cua thiab dej vapor yog siv los simulate qhov tseeb cov khoom siv hluav taws xob, thiab cov adsorption ntawm NOx los ntawm cov pa roj carbon activated suav nrog lub cev adsorption thiab tshuaj adsorption. Nyob rau hauv cov xwm txheej tsis muaj SO2 roj nyob rau hauv cov pa khiav, cov nitrogen tshem tawm efficiency ntawm activated carbon yog siab tshaj 75 feem pua thaum cov activated carbon mus txog lub dynamic adsorption equilibrium. Kev sib xyaw ntawm siab -purity SO2, NOx, huab cua thiab dej vapor tau siv los simulate cov khoom siv hluav taws xob tiag tiag. Thaum SO2 thiab NOx muaj nyob rau hauv cov roj ntws, lub peev xwm adsorption thiab adsorption saturation lub sij hawm ntawm activated carbon nce, thaum lub desulfurization efficiency, adsorption ceev thiab adsorption band ntev hloov me ntsis. Vim yog hloov NO los ntawm SO2, NOx adsorption muaj peev xwm thiab dynamic adsorption equilibrium lub sij hawm ntawm activated carbon txo sharply, lub nitrogen tshem tawm efficiency yog tsawg, qhov ntev ntawm NOx adsorption band nce, thiab lub adsorption ceev txo. Tsis yog SO2 lossis NOx nyob hauv lub chaw ua haujlwm adsorption ib leeg, tab sis co-muaj nyob rau hauv lub chaw ua haujlwm adsorption. Activated carbon preferentially adsorbs SO2 xaiv, thiab NOx ntawm lub cev adsorption yog hloov thiab daws los ntawm SO2. Chemisorbed NOx tuaj yeem txhawb nqa cov adsorption ntawm cov pa roj carbon activated ntawm SO2. Nyob rau tib lub sijhawm, SO2 tuaj yeem txhawb nqa cov adsorption ntawm NOx los ntawm cov pa roj carbon activated.
