Document 3JngBBxrqxeMkqRr1kB871XMn

CHEMICAL RESISTANCE AGAINST H2SO4 Chemical resistance Material properties Effects of chemical media Resistance against various media Case studies PVDF and ECTFE used for sulphuric acid Description of sulphuric acid slightly yellow viscous liquid (oil of triviol) soluble in water at all concentrations Diprotic acid Corrosive due to its - strong acidic nature, - strong dehydrating property - strong oxidizing property (concentrated acid) CHEMICAL RESISTANCE AGAINST H2SO4 Chemical resistance Material properties Effects of chemical media Resistance against various media Case studies Resistance of PVDF against sulphuric acid Temperature [C] Maximal admissible concentration of H2SO4 23 96,3 50 93 100 85 120 80 150 70 (no pressure) Information based on chemical resistance tests of the raw material supplier CHEMICAL RESISTANCE AGAINST H2SO4 Chemical Resistance of PVDF against sulphuric acid resistance Brown discoloration Permeation Material properties H2SO4 Concentration Temperature Hoop stress V max Time at rupture H2O V max without rupture Effects of % C MPa hours MPa 97 10 54700 chemical media 96 50 18 37650 23 93 18 > 54900 * Resistance 96 1 8600 93 100 4 7900 12.5 against various 9800 6 > 9200 11 54530 media 93 120 3 296 9.5 80 9 > 17500 * Case studies 90 2 1825 80 150 5 > 1700 5.5 70 fCR = H2SO4 / H2O 4 > 30000 fCR 0.43 0.78 0.78 < 0.1 < 0.3 0.48 < 0.88 < 0.1 0.94 < 0.1 (0.91) 0.72 CHEMICAL RESISTANCE AGAINST H2SO4 Chemical resistance Material properties Effects of chemical media Resistance against various media Case studies Sulphuric acid - brown discoloration Test criteria: 200 h at 95C V=11,5 N/mm Stopped after 240 hours Burst pressure 20C; 0,08 bar/sec 98 bar CHEMICAL RESISTANCE AGAINST H2SO4 Chemical resistance Material properties Effects of chemical media Resistance against various media Case studies High concentrated sulphuric acid (concentration: >96,3%) SO3(g) + H2O(l) H2SO4(l) -H2O Sulfur trioxide (SO3) CHEMICAL RESISTANCE AGAINST H2SO4 Chemical resistance Material properties Effects of chemical media Resistance against various media Case studies Resistance of PVDF against sulphur trioxide, which is formed by sulphuric acid >96,3% Deshydrofluorination Permeation Increase in weight (>5%) Stress cracking corrosion Typical phenomenon if SO3 only is present in very small amounts Physical and chemical degradation ECTFE is resistant against sulphuric acid with a concentration >96,3% without any restrictions CHEMICAL RESISTANCE AGAINST H2SO4 Chemical resistance Material properties Effects of chemical media Resistance against various media Case studies Medium: Temperature: Medium: Temperature: sulphuric acid 98% 20C sulphuric acid 96% 20C - 30C CHEMICAL RESISTANCE AGAINST H2SO4 Chemical resistance Material properties Effects of chemical media Resistance against various media Case studies Medium: Temperatrure: sulphuric acid 98% 20C The solution ETHYLENCHLORTRIFLUORETHYLEN - ECTFE