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Program for CUI Prevention at a Refinery

Gordon H. Hart, P.E.Artek Engineering, LLCBring on the Heat 2013

New Orleans, LAJune 6, 2013

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Project Objectives

• Make recommendations to an oil refinery on methods for minimizing occurrences and severity of Corrosion Under Insulation

• Maintain as many existing materials, procedures, and practices as practical while reducing CUI

• Minimize insulation first cost and life cycle cost• Maximize life of pipe & equipment and of

insulation systems• Enhance safety at the refinery

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Primary Methods

• Identify practices that should be continued• Identify practices that should be changed and

recommend new practices• Identify practices that should be discontinued• Recommend new practices to minimize water

intrusion into thermal insulation• Premise: there is no single “silver bullet”

solution to reducing CUI

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References

1. NACE Standard Practice 0198-2010: “Control of Corrosion Under Thermal Insulation and Fireproofing Materials—A Systems Approach”

2. API Recommended Practice 583, 2nd Draft (Sept, 2012), “Corrosion Under Insulation and Fireproofing”.

3. Several articles from journals4. ASTM material specifications

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Background• Refinery site for over 100 years• Two units constructed in late ‘60’s, early ‘70’s using asbestos-

reinforced calcium silicate insulation with aluminum jacket (with much still in place)

• Several other units constructed since then mostly using asbestos-free cal-sil insulation

• Use of cellular glass insulation, for pipes with operating temps < 450°F, started in 2010

• Removable/Reusable blankets used on many heat exchanger heads & valve bodies but not on flanges

• Use of protective coatings has started recently• Steam tracing is being replaced by electric tracing

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Much of the insulation in good condition

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Much of the insulation in good condition

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What are some of the problems?

• Pipe thinning due to CUI at certain locations (i.e., a pipe is only as strong as its weakest point)

• Limited budget for X-ray examination of pipes and only smaller pipes can be done

• Limited budget for insulation maintenance and replacement

• Most older pipes & equipment were never coated for protection for CUI

• Some pipes were insulated that may not need it

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What are we trying to avoid?

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Problem # 1: Insulation System in Poor Condition or missing

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Solution to Problem # 1: Replace with specified materials

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Problem # 2: Use of low compressive strength insulation on many fittings

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Solution to Problem # 2: use high compressive strength insulation at fittings

Use of low CS insulation at elbows, on left, and high CS insulation at elbows, on right

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# 3: Placement of insulation too close to flanges

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Solution to Problem # 4: leave clearance

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Problem # 4: Gaps & tears in the metal jacketing

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Solution to Problem # 4: Replaceor use metalized PSA tape to repair

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Problem # 5: Missing metal jacketingSolution to # 5: Replace missing jacketing!

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Problem # 6: Shifted & exposed insulation

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Solution to Problem # 6: Repair with specified insulation materials

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Problem # 7: Use of temporary wrap insulation as a fast insulation fix

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Solution to Problem # 7

• Replace with either specified material or with removable / reusable wrap insulation that has silicone coated fabric

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Problem # 8: Deteriorated R/R blankets

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Solution to Problem # 8 – Replace with new, good quality R/R blankets

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Problem # 9: Pipe support design allows water intrusion

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One Solution to Problem # 9: use insulated pipe supports

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Another Solution to Problem # 9: install splash shields over pipe supports

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Problem # 10: Use of unjacketed, water absorbent insulation

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Solution to Problem # 10: only jacketed insulation or use unjacketed insulation that

is not water absorbent

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Problem # 11: Complex surfaces that allow lots of water intrusion

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Solution to Problem # 11: Either use R/R blankets plus high temp rubber insulation or do not insulate

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Problem # 12: Broken jacket seals

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Solution to Problem # 12: Either reseal jacket or use metalized PSA tape

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General Recommendation # 1:Use calcium silicate for temps ≥ 350°F

Features & Benefits: (1) very high, 100 psi compressive strength, (2) non-combustible (3) chemically inhibited and hence does not contribute to corrosion of steel when wet (4) maintains high strength up to 1200°F (5) long history of successful use at temps ≥ 350°F

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General Recommendation # 2:Use cellular glass for temps < 350°F

Features & Benefits: (1) does not absorb water (2) fairly high, 60 psi compressive strength, (3) non-combustible (4) does not contribute to corrosion of steel

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General Recommendation # 3: Continue using aluminum jacket w/ polysurlyn moisture barrier

Features & Benefits: (1) resistant to corrosion from HCs (2) inside moisture barrier is resistant to galvanic & pitting corrosion (3) when sealed, keeps out water

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General Recommendation # 4: continue using R/R blankets where

accessibility is needed

Features & Benefits: (1) removable & reusable insulation allows for mechanical maintenance (2) insulates effectively (3) does not absorb & hold water against steel surfaces (4) durable materials

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Other General Recommendations – either replace with specified materials or

5. Seal damaged aluminum jacket with caulk (prevents water intrusion)

6. Seal lap joints at 90° & gaps with metalized PSA tape or replace (prevents water intrusion)

7. Use protective coatings where operating temperature allows (protects steel from corrosion)

8. Use temporary wrap insulation that is suitable for operating conditions (does not hold water against steel surfaces and meets temperature requirements)

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Thank you for your attention

• Are there any questions?