WRF 4431 Webcast Guidelines for the Use of Stainless Steel in the Water & Desalination Industries

Transcription

1 No part of this presentation may be copied, reproduced, or otherwise utilized without permission. WRF 4431 Webcast Guidelines for the Use of Stainless Steel in the Water & Desalination Industries February 23, 2016

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3 PRESENTERS Erin D. Mackey PhD, PE Supervising Engineer Drinking Water and Reuse Brown and Caldwell Thomas Seacord Vice President Chief Technologist Desalination Carollo Engineers

4 Acknowledgements Sponsors. Water Research Foundation USBR Eastern Municipal Water District Other Funding Agencies. The Nickel Institute Corrosion Probe, Inc. Supporting Utilities. City of Goodyear Arizona PWD Water Replenishment Dist. of Southern California Orange Cty. Water Dist. Zone 7 Water Agency City of Santa Cruz, California Water Dept. Long Beach Water Dept. Tampa Bay Water San Diego Cty. Water Auth. Irvine Ranch Water Dist.

5 The Challenge There s a hole where it shouldn t be. But Oxnard officials might never know what exactly went wrong with two relatively young pumps at the City s $30-million desalter plant Corrosion science is so complicated. Excerpts taken from VENTURA COUNTY STAR March 18, 2013 Pump problems keep Oxnard desalter offline

6 The SST Challenge Pick a high enough grade of steel to provide the required protection but don t buy a higher grade than you need. 6 grades of steel compositions. Assemble the piping and other equipment correctly. Operate it properly.

7 The Problem Info Is Scattered Guidance on selecting materials is not in one location AWWA Standard Description C220 Stainless-Steel Pipe ½-inch (13 mm) and Larger C221 C223 C226 C227 C228 C230 Fabricated Steel Mechanical Slip-Type Expansion Joints Fabricated Steel and Stainless Steel Tapping Sleeves Stainless-Steel Fittings for Waterworks Service, Sizes ½-inch 72-inch (13 mm 1,800 mm) Bolted, Split Sleeved Restrained and Non-restrained Couplings for Plain End Pipe Stainless Steel Pipe Flanges for Water Service, Sizes 2-inch 72-inch (50 mm 1,800 mm) Stainless Steel Full Encirclement Repair and Service Connection Clamps

8 Neither Are Materials Specs ASTM Standard A240 A312 Description Chromium and Chromium-Nickel Stainless Steel Plate, Sheet and Strip for Pressure Vessels and for General Applications Seamless and Welded Austenitic Stainless Steel Pipes A403 A774 A778 A789 A790 A813 F593 F593 Wrought Austenitic Stainless Steel Piping Fittings As-Welded Wrought Austenitic Stainless Steel Fittings for General Corrosive Service at Low and Moderate Temperatures Welded, Unannealed Austenitic Stainless Steel tubular Products Seamless and Welded Ferritic/Austenitic Stainless Steel Tubing for General Service Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe Single or Double Welded Austenitic Stainless Steel Pipe Stainless Steel Bolts, Hex Cap Screws, and Studs Stainless Steel Nuts

9 Or Material Finish Specs ASTM Standard Description A380 A967 Cleaning, Descaling and Passivation of Stainless Steel Parts, Equipment and Systems Chemical Passivation Treatments for Stainless Steel Parts

10 The Solution: Develop a guidance document for engineers and consultants to help them properly specify the type of stainless steel most appropriate for a given water system and/or water treatment chemical system application. Tell people how to pick the right steel. Tell people how to use it properly.

11 The Approach Summarize the literature. Capture what people are experiencing. Fill in data gaps. Develop formal guidelines.

12 Let s Take a Quick Tour of the Basics

13 What Is Stainless Steel? O 2 O 2 O 2 O 2 O 2 Protective Cr 2 O 3 layer, 12% Steel alloy A metallic alloy whose Cr content is >12% by weight. For austenitic & duplex SS, Cr 2 O 3 layer forms a corrosion-resistant barrier on the surface.

14 What Is Stainless Steel? O 2 O 2 O 2 O 2 O 2 Steel >12% Cr For other SS types (martensitic and ferritic), they simply contain >12% Cr, but there is no Cr coating.

15 What Is Stainless Steel? O 2 O 2 O 2 O 2 O 2 Protective Cr 2 O 3 layer, 12% Steel alloy The basic alloys used in water treatment are 304/304L and 316/316L austenitic stainless steels.

16 How Does Corrosion Occur? O 2 O 2 O 2 O 2 O 2 The surface becomes damaged, dirty, or otherwise compromised.

17 Warmer temperatures, chlorine, and chlorides accelerate the corrosion process. SPECIAL CHALLENGES FOR DESALINATION

18 Crevice Attack An electrochemical cell forms in a tight Metal-to-Metal joint. The crevice gap dimension is critical. Cl - is a catalyst.

19 Pitting Attack BULK SOLUTION M +2 Cathode 2M +2 +2OH - M(OH) 2 O 2 + 4e- + H 2 O 4OH- Anode 2M 2M e- Cl - is attracted to anode forms Metal-Cl ph at bottom drops Cl - is even more attracted to the anode Process speeds up with increasing Cl - & Temp.

20 Microbially Induced Corrosion Can Also Be A Significant Problem Like crevice corrosion attack. Tubercules serve as microenvironments. Bacteria form a biofilm. Becomes a tubercule. Anodic and cathodic sites develop and a corrosion cell is formed. Aggressive chemicals can accumulate and accelerate the rate of corrosion.

21 Analysis of Opportunities for Corrosion Mitigation STEP 1 FIGURE OUT WHAT MATERIAL YOU NEED (LITERATURE REVIEW)

22 Cutoffs Where Crevice Corrosion Aided by Cl - &/or OCl - at Ambient T. Is Unlikely Material 304/304L stainless steel 316/316L duplex 2205 Duplex 2205 Duplex 2507 Alloy 254SMO: AL-6XN Ferralium 255 Zeron 100 Ferralium 255 Alloy 654Mo Zeron 100; 654SMO Concentration of Free Chlorine in Feed Water 0 mg/l 2-3 mg/l 3-5 mg/l Chloride Concentration < 250 mg/l <100 mg/l - < 1,000 mg/l - <250 mg/l These are rules of thumb. ph, temperature, < 1,000 and aeration, up to high - free chlorine, - 3,600 mg/l high chloride & chlorine Austenitic mixes will < 3,600 influence and up to the best choice. & ,000 mg/l Duplex are best < 15,000 and up to 20,000 mg/l > 20,000 mg/l - -

23 When Choosing a SST alloy, PREN is a Valuable Guideline PREN = Pitting Resistant Equivalent Number. PREN = % Cr + 3.3(% Mo) + 16(%N)

24 TYPE PREN AUSTENITIC STAINLESS STEEL 304/304L 19 SAF /316L 25 LDX DUPLEX STAINLESS Alloy Alloy SUPER DUPLEX ALLOYS Ferralium 39 Zeron SUPER AUSTENITIC ALLOYS 254 SMO 43 AL6XN SMO 57 7% Mo 57 PREN Provides a General Indication, Test Data Provides Empirical Support PREN = Pitting PREN with Mo, N, Cr Combine with test data (ASTM G48 & G150) E.g., under X WQ, corrosion of SST followed PREN values.

25 There Is Only Limited Lab Data on the Effect of Chlorine on SST Corrosion Type 304/304L becomes 3-5 ppm. OCl - Resid. (mg/l as Cl 2 ) Maximum Depth of Attack (mm) Type 304 SS (PREN = 19) Base Crevice Plate Type 316 SS (PREN = 25) Base Crevice Plate High conc. of chlorine use higher alloyed material < Notes: 1. Water contained 23 mg/l of chloride. 2. Water contains 790 mg/l of chloride. Source: The Nickel Institute.

26 Analysis of Opportunities for Corrosion Mitigation STEP 2 LEARNING FROM FIELD EXPERIENCES

27 EMWD Stainless Steel Problems Well casings Desalter wells. Welds fabrication. Improper welds at Menafee Desalter. Menafee Desalter Welds Well Pump Corrosion Reclaimed water plants. Chlorine exposure. Well Casing Corrosion

28 The Bad Actors Problematic welds & improper passivation. Scratches & surface contamination. Dissimilar metals (i.e., galvanic corrosion). MIC. Use & disposal of construction test waters.

29 Design or Fabrication Can Serve as the Source of Crevice Attack Human-mediated. Stationary O-rings. Gasket surfaces. Poor root pass pipe welds. Skip welds. Paint, oil/grease, tape. Bolted joints. MIC. Crustaceans. Sticky sediments. Bacterial colonies. Sediment deposits.

30 Don t Field Weld The best QC is in a pipe fabricator s shop. Plan out the pipe fabrication. Field verify dimensions. Then build it. Note: This actually saves contractors money by not having to mobilize a certified welding crew. Note: Where field welding is allowed, purge inside the pipe with an inert gas (e.g., Ar) and passivate the welded area (inside and out preferred) exact procedures may vary with material type.

31 Write Careful Specs and Require They Be Followed Specify shipping procedures: Ship the piping material on pallets with the ends capped off with non-metallic covers. Foam and shrink wrap surfaces. Piping should not rub against each other or other non-ss surfaces.

32 Nylon Strap (not chain) Pipe Shop Fabrication Isolate the SST from contact with the floor

33 Delivery Isolate pipes from each other Ship on wood pallet Wrap pipe to prevent metal contamination

34 Write Careful Specs and Require They Be Followed 1. Specify storage and handling procedures: Piping should be stored on pallets, not on ground. No iron contaminants (grinding or weld slag) should come into contact with piping. Lift with nylon straps, not metallic chains. 2. Specify testing conditions for piping to incl.: Drain and dry piping so that stagnant water is not present. Flush and drain high dose chlorinated solutions from piping immediately after disinfection testing.

35 Other Important Considerations Welding quality. Parts fabrication. Surface finishes. Approaches to passivation & pickling.

36 Take-Home Message Specifying SS is important but not always well understood in our industry. Critical considerations include: Nature of piping environment. Cl - OCl -, T. Proper handling and installation. Keep things clean. Don t scratch the pipes. Good maintenance to control MIC. There s a lot of information to sift through. A step-through guidance document will help us make the right decisions.

37 Conduct Testing STEP 3 FILL IN THE DATA GAPS

38 Testing: To address data gaps identified in the literature and industry surveys, long-term tests were conducted under controlled conditions (i.e., temp, ph, Cl -, & Cl 2 ). Test racks were assembled following ASTM G78 guidelines for crevice corrosion.

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40 STEP 4 DEVELOPING GUIDELINES GUIDING PRINCIPLES Needs to be easy to use. i.e., format that people find useful. Needs to also be a source to evaluate operation changes to existing systems. SOLUTION Present Guidelines in CSI MasterFormat TM. Use flow charts and decision trees to evaluate chemistry/metal alternatives.

41 CSI MasterFormat TM Part 1, General: Provides a summary, background information, reference standards, administrative and procedural requirements to the document user. Part 2, Products: Describes the quality of materials that are to be incorporated into the work, including, where appropriate, names of acceptable manufacturers. Quality requirements may include finishing techniques that should be used. Part 3, Execution: Describes, in detail, the preparation and actions to be taken to incorporate the products into the project.

42 Highlights from Part 1: General Reference Standards. Help to sort through 100s of standards! Design Requirements. Pipe manufactured to: ASME B36.19: 1/8-inch through 30-inch Schd 5S, 10S, 80S. AWWA C220: ½-inch and larger Thickness specified. Tank and equipment design requirements. Submittal Requirements.

43 Tables Help Navigate the Hundreds of Industry Standards for Each Metal Pipe and Tubing

44 Tables Help Navigate the Hundreds of Industry Standards for Each Metal Pipe fittings

45 Tables Help Navigate the Hundreds of Industry Standards for Each Metal Cast Shapes

46 Tables Help Navigate the Hundreds of Industry Standards for Each Metal Bar Shapes & Fasteners

47 Highlights from Part 2: Products Material Selection. Decision Tree to consider water chemistry. Pipe products. Wall thickness. Weld procedures. Fabrication requirements. Buried Piping. Soil chemistry & cathodic protection. Pipe fittings. Fabrication requirements. Fasteners. Cleaning procedures & surface finishes.

48 Decision Trees Help Determine the Appropriate Metal Decisions for Design & Operation Which Metal is Appropriate? Cl - <200 mg/l Cl 2 2 mg/l Cl - <1,000 mg/l Cl 2 4 mg/l Cl - <10,000 mg/l Cl 2 5 mg/l Cl - <20,000 mg/l Type 304/304L Austenitic or Duplex with PREN 25 (e.g., Type 316/316L, LDX 2101, Alloy 2205) Austenitic or Duplex with PREN 43 Austenitic or Duplex with PREN 45

49 Weld Fabrication Example

50 Pipe Fitting Example

51 Highlights from Part 3: Execution Protection & delivery requirements. Hydrostatic testing guidelines. Disinfection guidelines.

52 Future Work Additional Laboratory Work. Affect of Anoxic Conditions. Dissolved Iron. Expanded guidelines for martensitic and ferritic materials. Hard shapes (bars, ball bearings, etc.). XD15NW X105CrMo17

53 We gratefully acknowledges that the Water Research Foundation and the U.S. Bureau of Reclamation are funders of certain technical information upon which this publication (manuscript)(presentation) is based. Carollo Engineers thanks the Water Research Foundation for their financial, technical, and administrative assistance in funding the project through which this information was discovered.

54 Thank You Comments or questions, please contact: For more information visit: