Cov nroj tsuag caustic soda raws li cov tshuaj chlor-alkali txheej txheem tsis yog ib lub tshuab tab sis ib qho kev tsim hluav taws xob txuas ntxiv. Txhua ntu ntawm cov nroj tsuag ua ib qho kev hloov pauv lossis ua kom huv.
Brine Npaj System
Cov txheej txheem brine npaj hloov cov khoom siv ntsev (NaCl) rau hauv saturated brine haum rau electrolysis pub. Hauv feem ntau cov membrane chlor-alkali tsim, lub hom phiaj brine concentration yog tswj ntawm kwv yees li 300-310 g / L NaCl.
Lub kaw lus feem ntau suav nrog cov ntsev yaj lub tank, agitators, coarse filtration screens, thiab lub voj voog brine. Lub tank dissolution yog tsim los tswj lub sijhawm nyob hauv, feem ntau yog 2-4 teev, kom paub meej tias cov kua ntsev sodium chloride ua tiav.
Undissolved impurities xws li xuab zeb, av nplaum, thiab insoluble ntsev raug tshem tawm los ntawm kev sib cais los yog hydrocyclone. Cov zis brine yog ces pauv mus rau purification seem.
Kev tsim ntawm lub subsystem no ncaj qha cuam tshuam rau lub neej ntawm daim nyias nyias, txij li cov khoom raug tshem tawm saum toj no 1 mg / L tuaj yeem ua kom cov membrane fouling thiab nce cell voltage dhau sijhawm.
Brine Purification Unit
Lub brine purification system tshem tawm cov divalent cations xws li calcium (Ca²⁺), magnesium (Mg²⁺), thiab taug qab cov hlau hnyav uas cuam tshuam nrog kev ua haujlwm ntawm daim nyias nyias. Hauv daim nyias nyias chlor-alkali systems, calcium thiab magnesium concentrations feem ntau yuav tsum raug txo kom qis dua 20 ppb (ib feem ntawm ib billion).
Tus qauv purification txoj kev yog tshuaj los nag los siv sodium carbonate (Na₂CO₃) thiab sodium hydroxide (NaOH). Cov tshuaj tiv thaiv tsim insoluble calcium carbonate thiab magnesium hydroxide:
Ca²⁺ + CO₃²⁻ → CaCO₃↓
Mg²⁺ + 2OH⁻ → Mg(OH)₂↓
Cov precipitates no raug tshem tawm siv clarifiers los yog lamella sedimentation tso tsheb hlau luam ua raws li kev pom zoo, feem ntau 5-10 micron cartridge lim.
Polishing cov ntxaij lim dej tau teeb tsa hauv qab kom ntseeg tau ruaj khov zoo rau cov electrolyzers. Lub brine purification system kuj suav nrog pH tswj loops thiab ORP saib xyuas kom tswj tau cov tshuaj tiv thaiv.
Electrolyzer System (Membrane Cell Seem)
Cov electrolyzer yog lub hauv paus ntawm chlor-alkali txheej txheem. Cov nroj tsuag niaj hnub siv ion- pauv cov cell membrane, feem ntau ua raws li perfluorosulfonic acid (PFSA) daim nyias nyias.
Txhua lub xov tooj ntawm tes electrolyzer tau muab faib ua ib qho anode compartment thiab cathode compartment sib cais los ntawm cation -selective membrane. Brine yog pub rau hauv lub anode chamber, qhov twg chloride ions yog oxidized rau chlorine gas:
2Cl⁻ → Cl₂ + 2e⁻
Nyob rau sab cathode, dej raug txo kom hydrogen gas thiab hydroxide ions:
2H₂O + 2e⁻ → H₂ + 2OH⁻
Sodium ions migrate los ntawm daim nyias nyias thiab ua ke nrog hydroxide ions los ua sodium hydroxide (NaOH).
Cov kev ua haujlwm tsis zoo rau kev lag luam membrane muaj xws li:
Cell kub: 85-95 degree
Tam sim no ceev: 3.0-6.0 kA / m²
Lub cev muaj zog: 3.0-3.3V
NaOH concentration: 30-35 wt% (cov kua dej tawm ntawm tes)
Lub tshuab electrolyzer suav nrog cov xov tooj ntawm tes, electrodes (titanium anode nrog ruthenium / iridium txheej), nickel cathodes, thiab hydraulic sealing systems. Kev sib raug zoo ntawm tes thiab compression quab yuam yog tswj los tiv thaiv kom tsis txhob xau thiab tswj kev ua haujlwm ntawm daim nyias nyias.
Rectifier System
Lub tshuab rectifier hloov AC lub zog los ntawm daim phiaj mus rau DC lub zog xav tau rau electrolysis. Chlor-alkali nroj tsuag feem ntau ua haujlwm ntawm DC tam sim no siab heev, feem ntau nyob rau hauv thaj tsam ntawm 10 kA txog 200 kA nyob ntawm qhov muaj peev xwm cog.
Lub rectifier yog tsim los ntawm:
Transformer unit (qib- nqis thiab cais tawm)
Thyristor lossis IGBT rectifier modules
DC busbars
Cua txias system (cua lossis dej-txias)
Cov zis hluav taws xob feem ntau yog nruab nrab ntawm 100 V thiab 600 V DC nyob ntawm kev teeb tsa pawg. Tam sim no ripple tswj tau qis dua 5% kom tswj tau cov tshuaj tiv thaiv electrochemical ruaj khov.
Lub tshuab kho hluav taws xob feem ntau yog sib xyaw ua ke kom ua raws li kab sib chaws, tshwj xeeb tshaj yog nyob rau hauv loj - cov nroj tsuag loj tshaj 50,000 tons / xyoo NaOH muaj peev xwm.
Evaporation System
Cov txheej txheem evaporation nce NaOH concentration los ntawm kwv yees li 30-35% (electrolyzer tso zis) mus rau qib lag luam xws li 48% lossis 50% caustic soda tov.
Ntau -effect evaporation (MEE) feem ntau yog siv los txo cov pa noj. Ib qho kev teeb tsa raug suav nrog 2 txog 4 evaporation cuam tshuam ua haujlwm hauv kev txo qis.
Chav nkag yog feem ntau ntawm 3-6 bar saturated chav nyob ntawm cov nroj tsuag tsim. Lub tshuab nqus tsev nyob rau theem tom ntej yog khaws cia nyob ib puag ncig -0.08 txog -0.09 MPa txhawm rau txhim kho thermal efficiency.
Cov ntaub ntawv evaporator yuav tsum tiv taus alkaline corrosion ntawm qhov kub siab, yog li nickel-raws li alloys lossis stainless hlau tshwj xeeb (xws li 316L lossis duplex qib) feem ntau siv.
Chlorine Handling System
Cov roj chlorine uas ua rau hauv electrolyzer yog ntub, kub, thiab muaj cov kab mob hydrogen thiab brine pos huab. Ua ntej siv los yog liquefaction, nws yuav tsum tau txias thiab purified.
Cov khoom siv tshuaj chlorine suav nrog:
Gas txias ntauwd (txo kom kub txog ~ 35-40 degree)
Mist eliminators (tshem tawm entrained droplets)
Chlorine drying system (siv sulfuric acid lossis adsorption dryers)
Compressors (rau liquefaction lossis pipeline hloov)
Qhuav chlorine purity yog feem ntau tswj siab tshaj 99.5% rau kev lag luam siv. Cov ntsiab lus noo noo yog txo qis dua 30 ppm los tiv thaiv corrosion hauv cov khoom siv hauv qab.
Cov khoom siv hauv cov tshuaj chlorine raug xaiv raws li kev tiv thaiv corrosion, feem ntau suav nrog titanium, PVC-lined steel, lossis FRP piping.
Hydrogen Recovery System
Hydrogen generated ntawm lub cathode yog feem ntau saturated nrog dej vapor thiab muaj cov kab ntawm caustic pos huab. Cov txheej txheem rov qab ua haujlwm sib cais, txias, thiab compression.
Qhov system muaj xws li:
Gas - kua cais
Demister unit
Txias cua sov exchanger
Hydrogen compressor (diaphragm lossis ntsia hlau hom)
Optional purification unit (PSA lossis catalytic polishing)
Hydrogen purity tom qab sib cais feem ntau tshaj 99%. Dew point tswj yog qhov tseem ceeb los tiv thaiv condensation hauv cov kav dej.
Hauv ntau qhov kev lag luam, hydrogen yog ib qho:
siv los ua roj hauv boilers lossis chav tshuab
los yog xa tawm mus rau cov txheej txheem tshuaj synthesis xws li ammonia lossis methanol ntau lawm
Automation System (PLC / DCS)
Lub kaw lus tswj kev sib koom ua ke tag nrho cov txheej txheem rau hauv ib qho kev sib koom ua haujlwm platform. Feem ntau niaj hnub chlor-alkali nroj tsuag siv faib tswj systems (DCS) ua ke nrog programmable logic controllers (PLC) rau cov khoom siv- theem tswj.
Cov kev tswj xyuas tseem ceeb muaj xws li:
Brine concentration tswj (conductivity-raws li)
Electrolyzer txoj cai tam sim no
Cell kub tswj (ntawm brine ncig)
NaOH concentration xyuas (kev ntsuas ceev)
chlorine siab tswj
Hydrogen siab thiab ntws tswj
Cov cuab yeej cuab tam muaj xws li:
conductivity sensors (0-300 mS / cm ntau)
Kev ntsuas pH (0-14)
Differential siab sensors nyob rau hauv daim nyias nyias
flowmeter (electromagnetic los yog Coriolis hom)
Gas analyzers rau chlorine thiab hydrogen purity
Kev nrhiav tau cov ntaub ntawv feem ntau yog sau tseg ntawm 1-5 thib ob lub sijhawm nyob ntawm qhov kev tsim qauv. Tswb interlocks yog siv rau chlorine to detection thiab hydrogen overpressure tej yam kev mob.
Cov nroj tsuag caustic soda yog tsim los ua ib lub voj voog txuas ntxiv uas cov ntsev nyoos tau hloov mus rau hauv peb cov khoom ntws: sodium hydroxide, chlorine, thiab hydrogen. Kev ua haujlwm ruaj khov ntawm cov nroj tsuag yog nyob ntawm kev tswj cov khoom noj brine purity, ruaj khov DC tam sim no faib, thiab tswj cov thermal tshuav nyiaj li cas hauv ob qho tib si electrolysis thiab evaporation seem.
Ib qho kev sib txawv hauv brine impurity theem lossis rectifier instability ncaj qha cuam tshuam rau daim nyias nyias voltage thiab txo qhov system efficiency. Yog li ntawd, feem ntau engineering designs prioritize upstream purification thiab downstream gas tuav kev ntseeg siab ntau npaum li cov electrolyzer nws tus kheej.
Conclusion (Engineering Summary)
Los ntawm cov txheej txheem engineering foundations, lub caustic soda nroj tsuag yog ib tug nruj integrated electrochemical system uas muaj xws li tshuaj npaj, electrolysis, zog conversion, thermal concentration, roj tuav, thiab automation txheej.
Txhua lub subsystem muaj qhov ntsuas kev ua haujlwm tsis zoo, thiab kev ua haujlwm ntawm cov nroj tsuag yog txiav txim siab los ntawm kev ruaj ntseg ntawm cov kev txwv no ntau dua li ib qho khoom siv ib leeg.
Lub tswv yim tsim qauv tag nrho yog nyob ntawm peb qhov txwv:
ionic purity ntawm pub brine
hluav taws xob efficiency ntawm membrane electrolysis
kev nyab xeeb kev sib cais thiab tuav cov tshuaj chlorine thiab hydrogen
Cov kev txwv no txhais cov kev teeb tsa ntawm txhua yam khoom siv loj hauv chlor -alkali installation niaj hnub.
