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Corrosion by Hazardous Chemicals Otto Drescher, P.E.

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Presentation on theme: "Corrosion by Hazardous Chemicals Otto Drescher, P.E."— Presentation transcript:

1 Corrosion by Hazardous Chemicals Otto Drescher, P.E.

2 Summary Discuss Uses & Some Properties Discuss Uses & Some Properties Case History Case History Materials Selection Guidelines Materials Selection Guidelines

3 Sulfuric Acid Nitric Acid Nitric Acid Phosphoric Acid Phosphoric Acid Chlorine Chlorine HCl HCl HF HF Organic Acids Organic Acids Caustic Caustic Ammonia & Amines Ammonia & Amines Specific Chemicals

4 Sulfuric Acid Largest Tonnage of Inorganic ChemicalsLargest Tonnage of Inorganic Chemicals Major Use in Petroleum Refining, Fertilizers, Paints, Pigments, Dyes, Explosives, and pH ControlMajor Use in Petroleum Refining, Fertilizers, Paints, Pigments, Dyes, Explosives, and pH Control Powerful Oxidizing AgentPowerful Oxidizing Agent

5 Sulfuric Acid Conc. Acid is 70% to 100%Conc. Acid is 70% to 100% Oleum (Fuming) – 100% + excess SO 3 Oleum (Fuming) – 100% + excess SO 3 Dilute Acid - < 25% Dilute Acid - < 25% Contaminants Greatly Effect CorrosionContaminants Greatly Effect Corrosion

6 Erosion-corrosion in 93% H 2 SO 4 Carbon Steel Nozzle fps (1.2 – 1.8 m/s) at RT Design Velocity Limit is <2 fps (0.6 m/s)

7 °C°C°C°C °F°F°F°F Concentration, Wt.% Sulfuric Acid – Guidelines Materials Selection Boiling Point Curve Cb-3904L Steel Alloy B-2, B-3, B-4 TantalumGlassSi-Iron 316

8 Sulfuric Acid Sulfuric Acid Nitric Acid Phosphoric Acid Phosphoric Acid Chlorine Chlorine HCl HCl HF HF Organic Acids Organic Acids Caustic Caustic Ammonia & Amines Ammonia & Amines Specific Chemicals

9 Nitric Acid Major Use in Ammonium Nitrate and Phosphate Fertilizers, Nitro Explosives, Plastics, and DyesMajor Use in Ammonium Nitrate and Phosphate Fertilizers, Nitro Explosives, Plastics, and Dyes Always an Oxidizing AcidAlways an Oxidizing Acid

10 Nitric Acid Concentrated Acid is 67% to 95% Concentrated Acid is 67% to 95% Fuming Grades are > 99% Fuming Grades are > 99% HF Addition Makes It Reducing HF Addition Makes It Reducing Cl - Contaminantion Releases Nascent Cl 2 Cl - Contaminantion Releases Nascent Cl 2

11 Nitric-HF Acid Pickling Line Alloy 33 (33Cr-32Fe-31Ni-1.6Mo) Tank

12 Nitric Acid – Guidelines Materials Selection Concentration, Wt.% °F°F°F°F ° C Boiling Point Curve 304L 310 LCN Titanium 67% Aluminum TantalumSi-Iron 1815 LC Si

13 Sulfuric Acid Sulfuric Acid Nitric Acid Nitric Acid Phosphoric Acid Chlorine Chlorine HCl HCl HF HF Organic Acids Organic Acids Caustic Caustic Ammonia & Amines Ammonia & Amines Specific Chemicals

14 Phosphoric Acid Major Use in Phosphate Fertilizers, Food & Beverages, Drying Agents, Plasticizers, Oil Additives, Fire Retardants, and InsecticidesMajor Use in Phosphate Fertilizers, Food & Beverages, Drying Agents, Plasticizers, Oil Additives, Fire Retardants, and Insecticides Is a Reducing Acid, More So When Contaminated With Cl - and F -Is a Reducing Acid, More So When Contaminated With Cl - and F -

15 Phosphoric Acid Two Types of Pure Acid (85%):Two Types of Pure Acid (85%): o C. P. Grade o Food Grade Superphosphoric Acid - > 105% Superphosphoric Acid - > 105% Industrial Grades May Be Contaminated With Cl -, F -, and Fe +++ Industrial Grades May Be Contaminated With Cl -, F -, and Fe +++

16 Preferential Attack in H 3 PO 4 Ambient Temperature, Steam Traced CompareThickness

17 Phosphoric Acid – Guidelines Materials Selection Concentration, Wt.% °F°F°F°F °C Boiling Point Curve 316L 317L C-276G-3G-30G /904L Alloy 28, 31

18 Sulfuric Acid Sulfuric Acid Nitric Acid Nitric Acid Phosphoric Acid Phosphoric Acid Chlorine HCl HCl HF HF Organic Acids Organic Acids Caustic Caustic Ammonia & Amines Ammonia & Amines Specific Chemicals

19 Chlorine Uses - Inorganic Chlorides Salts Chlorides Salts Bleaching Bleaching Chlorination Chlorination Dyes Dyes Rockets Rockets Explosives Explosives Uses - Organic Drugs Drugs Plastics Plastics Solvents Solvents Insecticides Insecticides PVC PVC Deodorants Deodorants

20 Chlorine Poisonous, greenish-yellow gas Poisonous, greenish-yellow gas Does Not Attack Metals < 400 °F (204 °C), Does Not Attack Metals < 400 °F (204 °C), Except Ti Except Ti Moisture aggravates corrosivity Moisture aggravates corrosivity HOCl is a Powerful Oxidizing Acid HOCl is a Powerful Oxidizing Acid

21 Chlorine – Guidelines Materials Selection Liquid Cl 2 – Carbon Steel ( Dry! ) Liquid Cl 2 – Carbon Steel ( Dry! ) Cl 2 Gas Cl 2 Gas o Carbon Steel to 250 °F (121 °C) Wall Temp o Caution! Carbon Steel May Ignite o Alloy 400 to 570 °F (299 °C) Wall Temp

22 Chlorine – Guidelines Materials Selection Chlorinated OrganicsChlorinated Organics o Carbon Steel to 200 °F (93 °C) Wall Temp o Alloys 400 & 200 to B.P. Chlorinated Waters – Titanium, C-276Chlorinated Waters – Titanium, C-276

23 Sulfuric Acid Sulfuric Acid Nitric Acid Nitric Acid Phosphoric Acid Phosphoric Acid Chlorine Chlorine HCl HF HF Organic Acids Organic Acids Caustic Caustic Ammonia & Amines Ammonia & Amines Specific Chemicals

24 Hydrochloric Acid 2 nd in Importance to Sulfuric Acid2 nd in Importance to Sulfuric Acid Major Use in Pickling Steels, Oil Well pH, Chemical Cleaning, Ore Reduction, Food Processing, Synthetic Rubber, and Regeneration of Ion Exchange ResinsMajor Use in Pickling Steels, Oil Well pH, Chemical Cleaning, Ore Reduction, Food Processing, Synthetic Rubber, and Regeneration of Ion Exchange Resins

25 Hydrochloric Acid Anhydrous is Non-corrosive, Very Hygroscopic Anhydrous is Non-corrosive, Very Hygroscopic Strong, Reducing Acid Strong, Reducing Acid Attacks Most Metals Below H 2 in EMF Series Attacks Most Metals Below H 2 in EMF Series Forms Metal Chlorides and Liberates H 2 Forms Metal Chlorides and Liberates H 2

26 Hydrochloric Acid Attacks Noble Metals Only If DO or Oxidizing Attacks Noble Metals Only If DO or Oxidizing Contaminants Are Present (Fe +++ ) Contaminants Are Present (Fe +++ ) Water Solution is 28% – 35% Water Solution is 28% – 35% Commercial Grade is Muriatic Acid Commercial Grade is Muriatic Acid Constant Boiling Mixture is 20.2% Constant Boiling Mixture is 20.2%

27 HCl Pitting Corrosion Alloy 825 Pickling Hook in Heated Acid Contaminated With Fe +++

28 Hydrochloric Acid – Guidelines Materials Selection Concentration, Wt.% B-2, B-3 ZirconiumTantalum Air Free 200, 400 Boiling Point Curve °F°F°F°F °C C-Family

29 Sulfuric Acid Sulfuric Acid Nitric Acid Nitric Acid Phosphoric Acid Phosphoric Acid Chlorine Chlorine HCl HCl HF Organic Acids Organic Acids Caustic Caustic Ammonia & Amines Ammonia & Amines Specific Chemicals

30 Hydrofluoric Acid Major Uses are Refrigerants, Fluorocarbons,Major Uses are Refrigerants, Fluorocarbons, Etch/Polish Glass, Pickling, Ore Processing Etch/Polish Glass, Pickling, Ore Processing Acidification of Oil Wells Acidification of Oil Wells Is a Weak, Reducing AcidIs a Weak, Reducing Acid Anhydrous HF and HF Acid are Very HazardousAnhydrous HF and HF Acid are Very Hazardous Commercial Grades are 48% & 70%Commercial Grades are 48% & 70% Fluoride Ions Less Aggressive Than ChlorideFluoride Ions Less Aggressive Than Chloride

31 SCC of Alloy 400 in HF Bubble Caps Exposed to Aerated Vapors

32 HF Acid – Guidelines Materials Selection Concentration, Wt.% °F°F°F°F °C°C°C°C Boiling Point Curve , 400, C-276, C-22, 686

33 Sulfuric Acid Sulfuric Acid Nitric Acid Nitric Acid Phosphoric Acid Phosphoric Acid Chlorine Chlorine HCl HCl HF HF Organic Acids Caustic Caustic Ammonia & Amines Ammonia & Amines Specific Chemicals

34 Organic Acids Major Uses are Dyeing, Pigments, Pesticides, Tanning, Esters, Alcohols, Organic ChemicalsMajor Uses are Dyeing, Pigments, Pesticides, Tanning, Esters, Alcohols, Organic Chemicals Are Weak, Reducing AcidsAre Weak, Reducing Acids Less Corrosive as Carbon Chain Lengthens (or as Molecular Weight Increases)Less Corrosive as Carbon Chain Lengthens (or as Molecular Weight Increases)

35 Organic Acids Rank in Corrosivity: Rank in Corrosivity: Formic > Acetic > Propionic > Butyric Aeration & Temperature Increase Corrosion Aeration & Temperature Increase Corrosion Contaminants (e.g. Cl - ) Increase Corrosion Contaminants (e.g. Cl - ) Increase Corrosion

36 Crevice Corrosion Acetic Acid-Acetic Anhydride Distillation Column at 248 °F (120 °C) 316 Bubble Cap Attack Due to Oxygen-Concentration Cell

37 Selective Corrosion Boiling Acetic Acid Corroded More Than Base Metal Weld Metal Corroded More Than Base Metal Base Metal Corroded More Than Weld Metal

38 Organic Acids – Guidelines Materials Selection IGA Probable, if Low C Not Used IGA Probable, if Low C Not Used SCC Possible, if Chlorides Present SCC Possible, if Chlorides Present 304L For Storage and Low Temperatures 304L For Storage and Low Temperatures 316L For Higher Temperatures 316L For Higher Temperatures 6% Mo Alloys if Crevices & Cl - Present 6% Mo Alloys if Crevices & Cl - Present May Need 6% or Higher Mo Alloy Welds May Need 6% or Higher Mo Alloy Welds

39 Sulfuric Acid Sulfuric Acid Nitric Acid Nitric Acid Phosphoric Acid Phosphoric Acid Chlorine Chlorine HCl HCl HF HF Organic Acids Organic Acids Caustic Ammonia & Amines Ammonia & Amines Specific Chemicals

40 Sodium Hydroxide Caustic Soda Major Uses are Sodium Compounds, Metallurgical (Aluminum), Glass, Rayon Fibers, Cellophane, Paper Industry, Detergents, Bleaching, Whitening Products, Soaps, Cleaning (Dissolves Organics), pH ControlMajor Uses are Sodium Compounds, Metallurgical (Aluminum), Glass, Rayon Fibers, Cellophane, Paper Industry, Detergents, Bleaching, Whitening Products, Soaps, Cleaning (Dissolves Organics), pH Control Strong Alkali Strong Alkali KOH Is Very Similar to NaOH KOH Is Very Similar to NaOH

41 Caustic Cracking of Steel Heating Coil in 50% NaOH StressCorrosionCracking GeneralCorrosion

42 Caustic Soda Corrosion Rates for 304 Concentration, Wt.% Boiling Point Curve °F°F°F°F °C°C°C°C mpy (0.03 – 0.76 mm/y) >30 mpy (0.76 mm/y) (0.76 mm/y) Freezing Point Curve < 1 mpy (0.03 mm/y)

43 Caustic Soda Stress Corrosion Cracking Zones Concentration, Wt.% °F°F°F°F °C°C°C°C 304 C Steel Freezing Point Curve Boiling Point Curve

44 Caustic Soda – Chlorate Free Corrosion Rates for Alloy 200 Concentration, Wt.% Boiling Point Curve °F°F°F°F °C°C°C°C < 0.1 mpy (0.003 mm/y) >5 mpy (0.13 mm/y) mpy (0.03 – 0.13 mm/y) Freezing Point Curve mpy (0.003 – 0.03 mm/y)

45 Sulfuric Acid Sulfuric Acid Nitric Acid Nitric Acid Phosphoric Acid Phosphoric Acid Chlorine Chlorine HCl HCl HF HF Organic Acids Organic Acids Caustic Caustic Ammonia & Amines Specific Chemicals

46 Ammonia Major Uses are Organic Compounds, Drugs, Plastics, Dyes, Fertilizers, Explosives, Production of Nitric Acid, Ammonium Salts, Refrigerant, Cleaning Agents Major Uses are Organic Compounds, Drugs, Plastics, Dyes, Fertilizers, Explosives, Production of Nitric Acid, Ammonium Salts, Refrigerant, Cleaning Agents 4 th Most Important Chemical 4 th Most Important Chemical

47 Ammonia – Guidelines Materials Selection Anhydrous Ammonia Is Non-corrosiveAnhydrous Ammonia Is Non-corrosive Except for SCC of Steel Except for SCC of Steel NH 3 + H 2 O NH 4 OHNH 3 + H 2 O NH 4 OH Water Dilution Forms Ammonium Water Dilution Forms Ammonium Hydroxide - Inhibits SCC of Steel Hydroxide - Inhibits SCC of Steel Ingress of Water and O 2 Corrosive to Cu and Cr-free Ni Alloys (Even ppm)Ingress of Water and O 2 Corrosive to Cu and Cr-free Ni Alloys (Even ppm)

48 Ammonia – Guidelines Materials Selection Corrosion of Steels Through Stainless Steels May Be Caused By CO 2 Contamination (Ammonium Carbamate)Corrosion of Steels Through Stainless Steels May Be Caused By CO 2 Contamination (Ammonium Carbamate) Chloride Contamination Can Reduce Life of Stainless Steel EquipmentChloride Contamination Can Reduce Life of Stainless Steel Equipment

49 Summary Discussed Specific Chemicals Discussed Specific Chemicals Reviewed Use & Some Properties Reviewed Use & Some Properties Presented Materials Selection Guidelines for Each Chemical Presented Materials Selection Guidelines for Each Chemical

50 The End Questions?


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