Ntawm Dab tsi tshwj xeeb ntawm Hydrochloric Acid ntawm 50 Degrees Celsius Puas yog 1.2 millimeter 316 Stainless Hlau Sheath Kev Pitting Nkag Hauv 500 Teev ntawm Kev Kub Kub Nruam Nruam?

316 stainless hlau feem ntau suav hais tias yog ib qho khoom siv tsis zoo rau cov khoom siv hluav taws xob rau hluav taws xob uas tau teev tseg los ntawm cov txheej txheem chemical engineers rau hydrochloric acid lub luag haujlwm hauv cov hlau pickling, pH kho thiab rov tsim dua tshiab. Hydrochloric acid yog ib qho kev txhoj puab heev txo cov kua qaub. Chloride ions tsom rau cov txheej txheem passive ntawm stainless hlau. Tsis zoo li sulfuric los yog nitric acid tsis muaj ntau qhov concentration uas nws muaj qhov ua tau zoo heev rau 316. Ntawm qhov kub thiab txias hauv cov tshuaj dilute heev, txawm li cas los xij, 316 tuaj yeem ua rau lub neej siv tau rau cov ntawv tsis yog-tseem ceeb. Lub sij hawm nws yuav siv sij hawm rau pitting rau propagate los ntawm sab nraud nto mus rau sab hauv phab ntsa nyob ntawm phab ntsa thickness ntawm lub sheath. Kab lus no qhia txog qhov ntsuas ntawm qhov tshwj xeeb hydrochloric acid concentration ntawm 50℃uas ua rau pitting nkag ntawm 1.2 hli 316 sheath hauv 500 teev ntawm kev ua haujlwm tas li ntawm qhov nruab nrab muaj watt ntom ntom.

"Pitting Corrosion ntawm 316 Stainless Hlau hauv Dilute HCl.
Lub corrosion ntawm 316 nyob rau hauv hydrochloric acid tshwm sim raws li pitting, tsis uniform thinning. Yog hais tias lub qhov dej yog tsim los ntawm qhov chaw tsis zoo, suav nrog lossis tsis muaj zog hauv cov yeeb yaj kiab passive, nws yuav nthuav tawm sai heev vim yog qhov xwm txheej autocatalytic ntawm chloride nres. Qhov tseem ceeb pitting peev xwm ntawm 316 hauv cov tshuaj chloride diminishes nrog nce kub thiab chloride concentration. Qhov chaw pib chloride concentration rau qhov pib yog li 50-100 ppm (0.005-0.01% HCl) ntawm 50 degree. Hauv qab no qhov pib pitting yog qhov tsis tshua muaj thiab cov nqi corrosion raug tsawg dua 0.05 hli / xyoo. Tshaj li qhov pib no, pitting yuav zoo li thiab tus nqi ntawm qhov propagation nce sai nrog cov ntsiab lus chloride. Lub sij hawm nkag mus rau 1.2 hli phab ntsa sheath yog tswj los ntawm qhov propagation tus nqi tom qab pib. Kev nthuav tawm tus nqi ntawm 50℃ntau ntawm 0.01 mm / hr hauv 0.1% HCl txog 0.10 mm / hr hauv 1% HCl. Kev nthuav tawm tus nqi yog ~ 0.03-0.05 mm / teev rau 0.5% HCl, implying ib phab ntsa 1.2 mm yuav nkag mus rau 24-40 teev tom qab pib lub qhov. Nyob ntawm qhov zoo ntawm qhov chaw thiab qhov seem seem, tag nrho cov kev pabcuam lub neej yog 120-540 teev, suav nrog lub sijhawm induction ntawm 100-500 teev rau qhov pib.

Tseem ceeb heev rau 500-teev lub neej
Cov kev pab cuam hauv qab no tau kwv yees los ntawm kev ntsuas immersion ntawm swaged 316 sheath qauv ntawm 50℃thiab polished nto ntawm lub tshuab ua lag luam. Ntawm 0.05% HCl (500 ppm chloride), qhov pib pitting yog li ntawm 800-1,200 teev thiab kev nthuav tawm yog qeeb ntawm 0.005 hli ib teev . 1.2 hli sheath yuav kav 1,000-1,500 teev tag nrho. Ntawm 0.10% HCl, lub sijhawm pib raug txo rau 400-600 h nrog kev nthuav tawm ntawm 0.010-0.015 mm / h, rau tag nrho lub sijhawm ntawm 500-800 h. Ntawm 0.15% HCl pib nyob rau hauv 200-300 teev Propagation 0.020-0.025 hli ib teev Tag Nrho Lub Neej 300-500 teev. Initiation 100-200 h ntawm 0.20% HCl Propagation 0.030-0.040 mm / h Tag nrho lub neej 150-300 h Qhov tseem ceeb ntawm HCl rau 500-teev lub neej yog li 0.12 txog 0.14%. Thaum los yog qis dua qhov kev xav no muaj ntau lub caij nyoog uas 1.2 hli 316 sheath yuav muaj sia nyob 500 lub sijhawm ua haujlwm tas mus li. Saum toj no concentration lub neej expectancy yog qis dua 500 teev. Cov txiaj ntsig no yog rau watt ntom ntawm 5-8 W / cm² uas ua rau cov tawv nqaij kub nce mus txog 55-60 degree. Thaum ntau dua watt ntom ntom, qhov kub ntawm qhov chaw siab dua txo qhov tseem ceeb ntawm qhov tseem ceeb ntxiv.

Hydrochloric Acid Service Concentration & Phab ntsa Thickness Matrix
Cov lus hauv qab no muab cov lus pom zoo 316 sheath phab ntsa thicknesses rau hydrochloric acid ntawm 50℃rau lub neej kev pab cuam. Qhov tseem ceeb xav tias watt ceev ntawm 5 mus rau 8 W / cm2 thiab ib txwm swaged nto tiav

HCl Concentration Chloride Concentration (ppm) Predicted Rate of Pit Growth at 50℃Yam tsawg kawg nkaus 316 Phab ntsa Thickness rau 500-teev lub neej Yam tsawg kawg nkaus phab ntsa Thickness rau 1,000-teev Daim Ntawv Pom Zoo Lub Neej
Tsawg dua 0.05%< 500 ppmBelow 0.005 mm/hour 0.8 mm 1.0 mm 316 acceptable for intermittent service 
0.05 - 0.10% 500 - 1,000 ppm 0.005 - 0.015 mm/hr 1.0 mm 1.6 mm 316 marginal; Cia siab tias lub neej luv
0.10 - 0.15% 1,000 - 1,500 ppm 0.015 - 0.025 mm / teev 1.2 mm 2.0 mm 316 tsis pom zoo rau kev pabcuam txuas ntxiv
0.15 - 0.20% 1,500 - 2,000 ppm 0.025 - 0.040 mm / teev 1.6 mm 2.5 mm Titanium lossis tantalum
0.20 - 0.50% 2,000 - 5,000 ppm 0.040 - 0.100 mm / hr Tsis siv tau Ua tsis tau Titanium xav tau
Tshaj 0.50% Tshaj li 5,000 ppmNtau tshaj 0.100 mm / teev Tsis tau txais Tsis tau siv tsis tau - cua sov hlau
Yog tias qhov concentration ntawm hydrochloric acid yog siab dua 0.15% ntawm 50 degree, 316 stainless hlau tsis yog cov khoom siv zoo siv txawm tias phab ntsa tuab. Qhov ceev ntawm qhov propagation npaum li cas thiab qhov tseem ceeb ntawm kev pheej hmoo ntawm abrupt perforation tsis tau ceeb toom yog muaj kev txhawj xeeb. Titanium (Qib 2 lossis Qib 7) muaj qhov ua tau zoo rau dilute hydrochloric acid mus txog 1% concentration ntawm 50 degrees C, nrog corrosion tus nqi <0.01 hli ib xyoo. Rau siab dua los yog kub koj xav tau tantalum. Thaum xaiv cov cua sov rau cov kev pabcuam hydrochloric acid qhov twg 316 raug txiav txim siab, cov kws ua haujlwm yuav tsum qhia txog kev kuaj daim coupon corrosion siv cov txheej txheem tiag tiag cov kua qaub thiab cov qauv ntawm cov khoom siv sheath ntawm qhov xav tau qhov kub thiab txias. Cov ntaub ntawv luam tawm muab kev kwv yees tab sis tus cwj pwm pitting cuam tshuam los ntawm qhov tseeb acid purity thiab kub tswj. Tus nqi ntawm ib lub rhaub tsis ua hauj lwm hauv hydrochloric acid - nrog rau cov hlau ion paug ntawm cov txheej txheem kev daws - feem ntau ntau dua li tus nqi ntawm kev kho dua tshiab rau titanium. Cov kev txawj ntse engineering qhia ntawm 50℃thiab siab dua 0.1% yog kom tsis txhob 316 tag nrho.