Lignin Fouling defi a nan pwodiksyon aditif
Solisyon lignosulfonate sodyòm (30%, pH 9) nan 90 degre yo itilize kòm superplasticizers konkrè. Lignin makromolekil adsorbe sou sifas aparèy chofaj PFA, fòme kouch izolasyon fouling. Konpozan baz asid-enèji sifas lib (^AB) mezire pa envès gaz chromatography (IGC) nan 90 degre predi adezyon lignin. Analiz kantitatif ki soti nan 8 plant melanj konkrè montre ke PFA ak ^AB pi ba pase 0.5 mJ/m² montre 90% pi ba adezyon lignin pase sifas ki gen ^AB pi wo a 2 mJ/m², pwolonje entèval netwayaj soti nan 2 semèn a 12 semèn.
Konpozan enèji gratis andigman ak Adhesion Lignin
Makromolekil lignosulfonat (pwa molekilè 20,000-80,000 Da) gen gwoup fenolik ak sulfonat ki gen gwo karaktè asid-baz. Adhesion fèt atravè entèraksyon asid-baz ak sifas PFA. IGC nan 90 degre mezi dispersive (^D) ak asid-baz (^AB) konpozan. Lower ^AB diminye travay adezyon.
| PFA Sifas Kalite | ^D nan 90 degre (mJ/m²) | ^AB nan 90 degre (mJ/m²) | Pousantaj Adhesion Lignin (mg/cm²·jou) | Tan pou 1mm Fouling nan 0.5 m/s (jou) |
|---|---|---|---|---|
| Kòm-moule (estanda) | 19 | 2.8 | 8.5 | 10 |
| Plasma-trete (idrofil) | 22 | 15 | 12 | 7 |
| Fliyò (ba enèji) | 16 | 0.8 | 3.2 | 25 |
| Espesyalite ki ba-asid-baz | 15 | 0.3 | 1.2 | 70 |
| Ultra-ba ^AB (trete) | 14 | 0.1 | 0.5 | 180 |
Vitès koule ak retire taye
Pi wo vitès koule retire lignin ki fèb adhere. Tès nan 90 degre ak konsantrasyon lignin 30%:
| Vitès koule (m/s) | Cheay mi (Pa) | Pousantaj Adhesion Lignin (ba ^AB PFA, mg/cm²·jou) | Ekilib epesè fouling (mm) |
|---|---|---|---|
| 0.2 | 2 | 1.2 | 0.8 |
| 0.5 | 5 | 0.8 | 0.4 |
| 1.0 | 10 | 0.4 | 0.15 |
| 1.5 | 15 | 0.2 | 0.05 |
| 2.0 | 20 | 0.1 | 0.02 |
Pou PFA estanda (^AB=2.8), menm 2 m/s bay 1.5 mg/cm²·jou adezyon.
Pwotokòl Mezi IGC
IGC a 90 degre lè l sèvi avèk sond ki pa-polè (dekan) ak polè (asetòn, etanòl). Asid-konpozan baz kalkile apati volim retansyon espesifik. Valè akseptab pou rezistans lignin:
^AB <1.0 mJ/m² pou rezistans modere
^AB <0.5 mJ/m² pou gwo rezistans
^AB < 0.2 mJ/m² pou adezyon ultra-ba
Estabilite andigman nan solisyon Lignosulfonate
Sifas ki ba- ^AB degrade sou tan an kòm lignin adsorbe, ogmante enèji sifas yo. Pou PFA fliyò (inisyal ^AB=0.8), apre 500 èdtan ekspoze, ^AB ogmante a 1.2; apre 2000 èdtan, a 1.8. Netwayaj peryodik retabli ba ^AB. Pou ultra-sifas trete ^AB ki ba (inisyalman 0.1), ogmante a 0.4 apre 1000 èdtan, toujou akseptab.
Epesè mi ak frekans netwayaj
Menm ak sifas ki ba-aderans, yo bezwen netwayaj peryodik. Epesè miray la detèmine severite metòd netwayaj:
| Epesè miray la | Metòd netwayaj rekòmande | Entèval netwayaj (ba ^AB PFA) | Pousantaj PFA Mete |
|---|---|---|---|
| 1.5mm | Tranpe chimik sèlman | 2 semèn (ultra-ba) | <0.01mm/year |
| 2.0mm | Chimik oswa dlo jè | 4 semèn | 0.02mm / ane |
| 2.5mm | Jet dlo oswa bwòs mou | 6 semèn | 0.03mm / ane |
| 3.0mm | Nenpòt metòd ki gen ladan bwose | 8 semèn | 0.05mm / ane |
Efè tanperati ak pH
Tanperati ki pi wo ogmante pousantaj difizyon lignin. Nan 90 degre, done jan pi wo a. Nan 70 degre, pousantaj adezyon yo 60% pi ba (0.3 mg/cm²·jou pou ^AB ki ba). Nan 110 degre, pousantaj doub. pH afekte solubilite lignin: nan pH 9 (pi bon pou melanj), lignin se konplètman idrosolubl. Nan pH 7, lignin presipite, ogmante adezyon 5 fwa kèlkeswa sifas PFA.
Gid Spesifikasyon pou Sèvis Lignosulfonate
For 30% sodium lignosulfonate at 90°C, pH 9, specify PFA with γ^AB below 0.5 mJ/m² (IGC at 90°C) and flow velocity >1.0 m/s at heater surface. Require supplier certification of IGC measurement with ethanol and decane probes. For wall thickness, 2.0mm is adequate with low γ^AB PFA. For continuous production with cleaning intervals >6 semèn, presize ultra-ki ba ^AB PFA (<0.2 mJ/m²) with 2.5mm walls. The premium for low γ^AB PFA (30-50% over standard) is justified by extending cleaning intervals from 2 weeks to 2-3 months in continuous admixture production, reducing downtime and labor costs. For batch operations with tank cleaning between batches, standard PFA with 2.5mm walls and weekly manual cleaning may be acceptable.
