Dab tsi yog Qhov Siab Tshaj Plaws Dej Hardness (ppm CaCO₃) rau Qib 7 Titanium Sheath rhaub hauv 5% Sodium Tripolyphosphate Solution ntawm 90℃los tiv thaiv Calcium Phosphate Scale-Induced Overheating?
Tso lus
Calcium ions precipitate li calcium phosphate (Ca₃(PO₄)₂) nplai hauv 5% sodium tripolyphosphate (STPP) ntawm 90 degree. Qhov ntsuas no yog tus cwj pwm los ntawm cov thermal conductivity tsawg ntawm 0.3-0.6 W / m·K (titanium, 21.9 W / m·K). Qhov siab tshaj plaws dej hardness pub yog 100 ppm li CaCO 3 kom tsis txhob overheating. Tshaj 100 ppm nplai thickness yog ntau tshaj 0.2 hli nyob rau hauv 500 h thiab tshav kub thauj mus los yog txo los ntawm 30%. Scale yog tsim raws li cov tshuaj tiv thaiv: 3Ca2+ + 2PO43- → Ca3(PO4)2↓
Mechanism ntawm Calcium Phosphate Scale Formation
STPP yog hydrolysed rau orthophosphate ntawm 90 degree. Calcium ions hauv dej hnov mob nrog orthophosphate los tsim calcium phosphate. Cov nag lossis daus yog nyob ntawm qhov kub thiab txias, thiab qhov kub ntau dua ua kom cov nplais ntau lawm. Cov nplai loj hlob raws li tuab, crystalline txheej uas adheres ruaj ntseg rau titanium nto. Ib zaug tsim, lub nplai yog qhov nyuaj rau tshem tawm siv cov kua qaub, vim calcium phosphate yog qhov tsis tshua muaj soluble hauv cov kua qaub uas muaj kev nyab xeeb rau titanium.
Quantitative Scale Formation raws li muaj feem xyuam rau Dej Hardness
Kev tswj xyuas ntawm Qib 7 titanium hauv 5% STPP ntawm 90℃rau 500 teev tau txais cov txiaj ntsig hauv qab no. Scale Thickness=0 µm, Scale Composition=Tsis muaj, Kev Hloov Kho Thaum tshav kub kub=0% (ntawm 0 ppm Hardness) Thickness yog 10-30 µm, muaj pes tsawg leeg yog calcium phosphate thiab qhov txo qis yog 5-15% ntawm 50 ppm. Qhov ntsuas qhov tseem ceeb yog 100 ppm. Thickness: 30-70 µm. Cov khoom xyaw: calcium phosphate. Kev txo qis: 15–30%. 150 ppm 60-120 µm Dense calcium phosphate 25-45 % Thickness 100 - 200 µm Composition Heavy scale Reduction 40 - 60% 250 ppm Ntawm 500 ppm thickness yog hnyav 200µm40, muaj pes tsawg leeg 60-80%.
Cov nyhuv ntawm STPP Concentration thiab Kub ntawm Hardness Tolerance
Qhov siab dua qhov concentration ntawm STPP thiab qhov kub thiab txias, qhov qis tshaj qhov tso cai dej hardness. Rau<0.1 mm scale, the permissible hardness is 150 ppm at 3% STPP and 90°C. Permitted is 150 ppm at 5% STPP and 80°C. Allowable at 5% STPP and 90°C is 100 ppm. 60 ppm at 5% STPP and 100°C is allowable. 50 ppm at 90°C and 10% STPP is allowed. Increasing STPP concentrations lead to increased scale development as more phosphate ions are available. The dynamics of precipitation are enhanced at elevated temperatures.
Phau ntawv qhia rau STPP rhaub Dej Hardness Control
Cov lus hauv qab no qhia cov lus pom zoo rau qhov siab tshaj plaws tso cai dej hardness rau Qib 7 titanium rhaub hauv 5% STPP ntawm 90 degree.
Dej Hardness (ppm CaCO3) Cia siab Scale Thickness Tom qab 500 teev (µm) Thaum tshav kub kub hloov pauv (%) Pom zoo ua<50 <30 <10 No action 50–75 30–50 10–20Monitor monthly 75–100 50–80 15–25 Use softened water 100–150 80–120 25–40 Water softener needed >150 >120 >40 Tsis tau
Tshaj Hardness Control Engineering
Corrosion nyob rau hauv - nplai yog cuam tshuam los ntawm qib titanium. Qib 7 muaj kev tiv thaiv zoo dua qib 2 tab sis kev tsim cov nplai zoo sib xws. Phab ntsa thickness muab kev hloov pauv cua sov; 2.0 hli phab ntsa nrog 0.2 hli nplai muaj 1.8 hli hlau, tab sis cov nplai insulates. Qhov kawg ntawm lub raj nto cuam tshuam rau nplai adhesion; Electropolished nto (Ra <0.3 µm) tso cai tshem tawm yooj yim dua. Ib qho dej softener (ion exchange) yuav siv lub hardness mus rau zero. Ib qho scale inhibitor xws li 10 ppm polyacrylic acid txo calcium phosphate scale kev loj hlob los ntawm 50-70%. Calcium phosphate scale yuav yaj thaum lub sij hawm tu nrog 5% HCl ntawm 50℃rau 30 feeb tab sis tej zaum yuav tsis zoo rau cov hnub nyoog teev.
Kev Paub Txog Kev Sau Ntawv
Rau qib 7 titanium sheath rhaub nyob rau hauv 5% STPP ntawm 90℃C, tswj dej hardness mus <50 ppm siv cov dej softener. Titrate txhua lub lim tiam los saib xyuas qhov nyuaj. Yog tias qhov hardness ntau dua 75 ppm, ua kom cov softener lub voj voog rov tsim dua lossis ntxiv cov nplai inhibitor . - Rau cov cua sov uas twb muaj lawm nrog calcium phosphate nplai: ntxuav nrog 10% citric acid rau 2 teev ntawm 70℃. Sodium tripolyphosphate pab. Tus engineer tswj cov dej hardness hauv qab 50 ppm los tiv thaiv overheating vim calcium phosphate nplai.
