OH&S practic ices as a cause of corrosion under in insulation? AOG 20 2017 17 Graham Ca Carli lisle Princ rincipal Co Corrosion and Coa Coatin ing Engin ginee eer
2. WHY 1. THERMAL INSULATE PROPERTIES OF TOPICS 3. TYPES OF MATERIALS INSULATION 8. THERMAL 4. OH&S βSAFE TO 10. CASE HISTORY INSULATION TOUCHβ specs MEG VSESSELS COATINGS 5. ISSUES WITH 11. CONCLUSION 9. TESTING INSULATION 7. MAINTAINING 6. MITIGATION COMPLIANCE OF CUI AOG 2017
Heat transfer Conduction Radiation Convection www. coolcosmos.ipac.caltech.edu AOG 2017
Thermal conductance AOG 2017
Thermal conductance πΉ βπππ’ ππππ₯ = βπ ΞπΌ ππππππ ππππ ππ π’πππππ ππ’π£π π π΄ πππ’ππ πππ π’βππππππ‘π‘ k = thermal conductivity, where π = π π + π π Q is measured in W/m 2 and k in W/m-K Therefore, in a time rate of steady state heat flow through a unit area of a material π·ππππ£ππ’ππππ = π π Normal lattice positions for atoms Positions displaced because of vibrations W.D. Callister, Chapt. 19- Materials Science and Engineering AOG 2017
Thermal inertia Silica fibre insulation Internal temperature = 1250 0 C (white-hot) Photograph courtesy of Lockheed Missiles & Space Company, Inc. AOG 2017
Why insulate? Thermal energy conservation To provide : οΌ Operational stability οΌ Energy efficiency οΌ Equipment reliability β’ Use materials with low thermal conductivities β’ Limit transfer of thermal energy β’ Insulate hot process from heat loss β’ Isolate cold process from heat gain www.aerogel.org AOG 2017
Personal protection Time in secs 1. No Burn 2. Burn Threshold 3. Burn ISO 13732-1 B o s c h u n d s i e m e n s h a u s g e r Γ€ t e g r u p p e AOG 2017
Types of insulation-Inorganic Aerogel Mineral wool Calcium Silicate Foam glass Perlite Vermiculite AOG 2017
Types of insulation-Organic Polyisocyanurate Rigid phenolic foam Polyethylene Various Elastomers Polyurethane AOG 2017
OH&S Specifications for βSafe to Touchβ Surfaces operating at temperatures in excess of 60ΒΊC (140ΒΊF) shall be fitted with personnel protection, consisting of SS 316 metal mesh guard. οΌ Operating above 60-70 0 C οΌ Any area that is accessible οΌ 2.1m vertically above grade or from platforms οΌ 0.9m horizontally from periphery of platforms, walkways or ladders. AOG 2017
Alternative personal protection Bound wire HDG mesh Physical hard barriers Expanded diamond SS mesh Perforated SS mesh (S) Perforated SS mesh (L) AOG 2017
Corrosion associated with insulation-General & Localised Chloride (Sulphide) induced stress corrosion cracking General & localised corrosion from moisture ingress due to damaged cladding and failed joint M. Chauviere, MoniCorr Inc. AOG 2017 www.flowgeeks.com
Corrosion associated with insulation-Galvanic Corrosion Galvanic corrosion from dissimilar metals due to no isolation between cathode and anode AOG 2017 M. Chauviere, MoniCorr Inc.
Corrosion associated with insulation-Crevice Corrosion AOG 2017
Mitigation of CUI Insulation specification β’ Closed cell foams/Aerogels (hydrophobic) β’ Low chloride β’ Low moisture Dry construction β’ Dry storage during shipment and storage β’ Protection during construction Design detail to prevent water ingress β’ Top hats to shed water β’ Arrange cladding to shed water β’ Drain points at the base of long vertical sections β’ Waterproof seals on pipe hangers and supports β’ Avoid joints in steam tracing lines AOG 2017
Mitigation of CUI οΌ Protect the substrate β’ Organic coatings (carbon and stainless steels) β’ Aluminium foil (austenitic stainless steel) β’ Inhibited insulation (silicates for the SCC of austenitic S.S.) οΌ Prompt maintenance/repair of damaged cladding οΌ Warm air drying (recent development - limited application) οΌ Review the need for insulation: β’ Lower temperatures later in life β’ Use guards rather than insulation for personnel protection β’ But, beware the possibility of introducing internal dew-point corrosion risks AOG 2017
Mitigation of CUI- Inspection οΌ With insulation in place: β’ Neutron back-scatter β’ Other novel NDE techniques οΌ Thermal imaging β’ Detects insulation breakdown (implies water present) οΌ Radiography β’ Detects corrosion thinning of pipe/vessel wall οΌ Removable βwindowsβ in cladding/insulation οΌ Remove insulation (common practice) AOG 2017
Maintaining compliance-PP Removing insulation or SS mesh 1. OH&S to consider thermal inertia properties of various materials in specifications 2. Use thermal insulation coatings to protect and modify surface AOG 2017
Thermal insulation coatings Binders Pigments β’ Hollow glass microspheres β’ Acrylic β’ Water Based Epoxy β’ Hybrid Acrylic/Epoxy β’ Silica aerogels β’ Polyurethane AOG 2017
Testing of thermal insulation coatings Acrylic Insulation Approximate Average Thermal Coating Technology Thermal Application Resistance per Conductivity Thickness- one Pass (x10 3 m 2 K/W) (mW/m-K) coat (mm) A Aerogel 35 1.5 42.9 B Ceramic 70 0.5 7.1 microspheres C Ceramic 100 0.375 3.8 microspheres D Ceramic 100 0.375 3.8 microspheres E None 300 0.1 0.3 P. Pescatore et. al., PCI Journal, 03/07/2013
Test Procedure Average Values Obtained Comparative Bench References Mark Values Corrosion resistance: No visible corrosion or No visible corrosion or The Effect of Four Cyclic wet/dry test coating defects after 500 coating defects after Commercially Available Steel (Prohesion)- G85-11 hours of exposure. 500 hours of exposure. Decontamination Processes and D1654 β 08 Rating of: on the Performance of 9 for plate 1 External Coatings NACE 9 for plate 2 9 for epoxies corrosion paper, San Antonia 9 for plate 3 Conference, 2014. Performance of Dry Film-Moisture vapour 14 g/m 2 /24hr Low < 15g (m 2 d) -1 EN ISO 7783-2:2001 transmission rate- D1653-13 Flexibility of cured 500 mm Pass (cold) No published values Flexibility and Toughness, film- D522-93a(2008) 50 mm Pass (hot) John Fletcher and Joseph Walker in Paint and Coating Testing Manual-15th. Edition of the Gardner-Sward Handbook
Test Procedure Average Values Obtained Comparative Bench References Mark Values Adhesion of cured 2.53 MPa Un-exposed 350 psi (2.4 MPa) film- D4541-09e1 4.6 MPa Cyclic wet/dry Nansulate EPX4 data sheet 2.47 MPa thermal cycling 4.4 MPa EPX4 to various substrates 8.2 MPa NanoPrime to Various substrates Norsok M-501 5 MPa (all cohesive failures) Resistance to thermal No checking No checking The Effect of Four cycling- D6944 β 15 No blistering No blistering Commercially Available Steel No cracking No cracking Decontamination Processes on the Performance of External Coatings NACE corrosion paper, San Antonia Conference, 2014. Thermal resistivity of Quantitative analysis of silica cured film- aerogel-based thermal ~0.060 W/m.K at 70% 0.071 W/m.K (thermal C335/C335M-10e1 insulation coatings, SΓΈren PVC (thermal conductivity) Kiil in Progress in Organic conductivity) Coatings, 2014
Validation of βsafe -to- touchβ H. Mitschke & G. More, Mascoat, NACE PP paper AOG 2017
Validation of βsafe -to- touchβ H. Mitschke & G. More, Mascoat, NACE PP paper AOG 2017
Validation of βsafe -to- touchβ AOG 2017
Case study: thermal insulation coatings Structure Glycol regeneration package OVERVIEW The client had a number of process vessels and piping that operated above Application Type Texture sprayer the βsafe to touchβ temperature, in accessible locations. Previous strategies Operating Environment 3 vessels using traditional insulation/cladding and metallic shields had led to either CUI or bi-metallic corrosion. Surface Preparation Power tool cleaning SOLUTION Diameter 1.1m β’ IAS employed the use of a patented formulation of a thermal insulation 80 -110 ο° C Operating Temperature coating 68 ο° C β’ Conducted a thermal survey to establish hot-spots and high risk areas Safe to Touch Temperature β’ Specified the appropriate thickness in order to achieve the required Corrosion Type Corrosion under insulation (CUI) temperature reduction β’ Applied the Nansulate coating system and ensured hot surfaces complied β’ Nansulate Heatshield EPX4 Proven Technology with HSE policy β’ NanoPrime Removes the need for traditional insulation Live system application & 30% quicker to apply Small footprint for equipment & reduced logistics AOG 2017
Case study: Thermal insulation coatings Glycol Flash Vessel Glycol Surge Vessel Cold Glycol Heat Exchanger Test points 38-VD-002 (3 coats) 38-VL-005 (3 coats) 38-HF-003 (6 coats) Vessel shell Day 1 Day 30 Vessel shell Day 1 Day 30 Vessel shell Day 1 Day 30 66 0 C 46 0 C 59 0 C 68 0 C 51 0 C 55 0 C 84 0 C 62 0 C 75 0 C Aft 57 0 C 51 0 C 60 0 C 69 0 C 48 0 C 65 0 C 88 0 C 63 0 C 72 0 C Centre 63 0 C 38 0 C 54 0 C 71 0 C 45 0 C 73 0 C 84 0 C 56 0 C 51 0 C Forward ~70 0 C ~70 0 C ~90 0 C ~74 0 C ~74 0 C ~94 0 C ~90 0 C ~90 0 C ~110 0 C Operating temp Day 1 Day 30 Vessel 38 HF 003 (aft end mid level) Vessel 38 HF 003 (aft end mid level) Thermocouple reading 62 0 C Magnetic thermometer reading 80 0 C Infrared reading 103 0 C AOG 2017
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