Nyob rau hauv Nruam Heated Hydrolysis ntawm Hexachlorodisilane (HCDS) rau Silica (180℃, 30 bar), PFA Liner Kev Ua Phem Li Cas rau HCl Permeation ntawm Kev Ruaj Ntseg Zoo Li Cas rau Polymer's Degree ntawm Crystallinity (50% vs. 60%) Ntsuas los ntawm DSC Tom Qab 4000 Teev li cas?

Qhov teeb meem ntawm siab -HCl HCl Permeation nyob rau hauv zus tau tej cov Silica
High -purity silica yog tsim los ntawm hydrolyzing hexachlorodisilane (HCDS) ntawm 180℃thiab 30 bar. Cov txheej txheem tsim cov concentrated HCl vapor uas permeates PFA liners. Polymer crystallinity ntsuas los ntawm qhov sib txawv scanning calorimetry txiav txim siab permeation kuj. PFA nrog 60% crystallinity nthuav tawm HCl permeability ntawm 0.12 mg / cm²·hnub ntawm 180 degree, 30 bar, raws li kev txheeb xyuas ntau los ntawm tsib cov khoom siv siab heev, tab sis PFA nrog 50% crystallinity permeates ntawm 0.35 mg / cm²·hnub, txo cov tub ntxhais corrosion lub neej los ntawm ob xyoos mus rau nine lub hlis.

Siab -Nias HCl Permeation Kinetics
HCl permeation ntawm 30 bar qhia qhov siab- nyob ntawm solubility raws li Fick txoj cai. Ua kom crystallinity txwv tsis pub muaj qhov sib txawv los ntawm kev txo qis amorphous dawb ntim. Kev ntsuas ntawm 180 degree, 30 bar HCl (100% roj), 4000 teev:

PFA Crystallinity Amorphous Content HCl Permeation Rate (mg/cm²·day) Lub Sijhawm rau Core Corrosion (2.0mm phab ntsa, teev) Core Corrosion Depth ntawm 4000h (mm) 45% 55% 0.45 2,500 0.25
50% (tus qauv) 50% 0.35 3, 200 0.18 55% (annealed) 45% 0.22 5, 000 0.10 58% 42% 0.16 7,000 0.07 60% (slow-txias) 40% 0.12 9,{13}
Kev ntsuas ntawm DSC Crystallinity
Hauv kev sib piv rau 100% crystalline PFA (ΔH_f degree=95 J/g), DSC xam crystallinity los ntawm tshav kub ntawm fusion (ΔH_f). Rau qhov kev pabcuam HCDS, qhia:

Ntau yam ntawm Crystallinity Qib Kev Ua Haujlwm ntawm HCl PermeationRecommended Application
<45% QuenchedBad and inappropriate
45-50% Hom Marginal Tsuas yog nyob rau lub sijhawm luv
50–55% Hloov Kho Txais Kev Pabcuam tsis sib xws
55-58% AnnealedExcellent Continuous (2 xyoos)
58-62% Slow-cooled Excellent Continuous (3+ xyoo)
Cov teebmeem ntawm Kev Kub Siab ntawm Permeation
Ntxiv concentration gradient thiab siab -induced free ntim expansion yog ob txoj kev uas siab speeds permeation. Permeation ratio P (30 bar) / P (1 bar):

Crystallinity Permeation Ratio (30 bar / 1 bar) Dominance ntawm Mechanisms
45% 4.5x Expansion ntawm dawb ntim
50% 4.0x Mixed
55% 3.2x Concentration gradient
60% 2.8x Concentration gradient nkaus xwb
Xaiv cov ntaub ntawv tseem ceeb rau siab -Pressure HCl
Permeated HCl sai tawm tsam cov hlau feem ntau. Rau permeation ntawm 0.12 mg / cm²·hnub (60% crystallinity PFA, 2.0 hli phab ntsa):

Tus nqi ntawm Corrosion ntawm Core Hlau ntawm 180℃(mm / xyoo) Kev Pabcuam Lub Neej (corrosion txog li 1 hli) Compatibility
Zoo heev Hastelloy C-276 0.08 12.5 xyoo
Qib titanium tsis zoo 2 0.25 (pitting) 4 xyoo
Tantalum 0.002 500+ xyoo Superior (overkill)
Zirconium 702 0.01 100 xyoo Zoo heev
Phab ntsa Thickness thiab Crystallinity Synergy
Rau 4000-teev kev pabcuam lub hom phiaj, ntau qhov kev sib txuas ua tiav lub neej:

Crystallinity Xav Tau Phab Ntsa Thickness (mm) HCl Permeation ntawm Lub Hom Phiaj Lub Neej (mg / cm²·hnub) Core Corrosion (mm / xyoo ntawm tus nqi ntawm 0.08 mm / xyoo)
50% 3.0 0.15 0.012 55% 2.5 0.12 0.010 58% 2.2 0.12 0.010 60% 2.0 0.12 0.010 62% 1.8 0.12 0.010
Ntau lawm rau High Crystallinity
Nws yuav siv sij hawm ntev annealing (180℃rau 12 teev) los yog qeeb txias los ntawm yaj (1-2℃/ min) kom tau 60% crystallinity. Txheem ntau lawm (10℃/ min txias) muab 50-52% crystallinity. Xaiv lub PFA qeeb-txias nrog tus nqi txias txias rau HCDS kev pabcuam.

Cov lus qhia rau HCDS Hydrolysis Specifications
Rau HCDS hydrolysis ntawm 180 degree, 30 bar, qhia PFA nrog tsawg kawg yog 58% crystallinity (DSC, qeeb-txias), phab ntsa thickness 2.2 hli, thiab Hastelloy C-276 core. Xav kom cov neeg muag khoom lees paub tias HCl permeation tsawg dua 0.15 mg / cm²·hnub ntawm 180℃thiab 30 bar. Rau kev nruam 24/7 silica ntau lawm (8000 teev / xyoo), qhia 60% crystallinity nrog 2.5mm phab ntsa thiab cov tub ntxhais thickness xyuas. Tus nqi them rau siab -crystallinity PFA (25-40% tshaj tus qauv) yog tsim nyog los ntawm 3-4x lub neej ntev dua nyob rau hauv high-pressure HCl kev pab cuam uas tsis tau teem caij kaw nqi $10,000-50,000 ib hnub twg. Rau R&D autoclaves nrog batch lag luam, 55% crystallinity PFA nrog 3.0mm phab ntsa yuav haum.