CHALLENGES OF A CORROSION CONTROL PROGRAM FOR A FLEET OF GAS FIRED AND GEOTHERMAL POWER PLANTS

Transcription

1 CHALLENGES OF A CORROSION CONTROL PROGRAM FOR A FLEET OF GAS FIRED AND GEOTHERMAL POWER PLANTS Presentation April 2012 GOALS OF CALPINE CORROSION CONTROL PROGRAM: Prevent loss of life and injury due to fire or explosions of natural gas piping systems or leaks in hydrogen or anhydrous ammonia piping. Minimize unplanned outages and loss of revenue to Calpine power plants. To minimize maintenance costs and preserve the value of the facilities. To prevent penalties fines and penalties by government regulatory agencies such as DOT and PUC. Preserve Calpine s reputation with the community and throughout the power industry. 1

2 Sacramento Valley CPN Pipeline Natural Gas Pipeline System (350+ Miles) Sacramento Valley Delta DOT Gas Pipelines 2

3 Sutter County Gathering Pipelines Gas Well Collection Lines 3

4 Gas Compression Gathering Lines Gas Dehydration DOT Regulated Pipelines 4

5 DOT pipelines become HCA areas in urban areas - Class 3 or by an identified site 70+ Gas Fired Calpine Power Plants 5

6 Freestone EC Pipeline and Power Plant Pastoria Power Plant and Pipeline 6

7 13 Miles Geysers Recharge Water Pipelines Geysers Geothermal Plant 7

8 Geysers Steep Terrain Challenge #1 Rapid Growth - To put technical documents in place for the installation and maintenance of corrosion control systems: 1. Standard Calpine Specifications 2. Construction Design Drawings. 3. Corrosion Maintenance Manual 4. Pipeline Mapping and GIS 8

9 Challenge #2 External Underground Bimetallic Corrosion Three necessary components for underground corrosion are: Metal Pipe Surface Metal Structure of Pipe Soil or Water Environment (where ions can exchange with the environment) 9

10 What is Corrosion? Basic Common Corrosion Ore + = Refining + = FeO 2 Environment (Electrolyte) Bi-Metallic Corrosion Corrosion Copper Steel 10

11 Electrochemical Series Material Voltage Magnesium -1.6 More Active Zinc -1.1 Steel -.5 Copper 0 Cast iron +.1 Steel in concrete +.1 Silver +.2 Gold +.2 Carbon +.4 More Noble Flashlight Battery Zinc (-1.1V) to Carbon (+.4V)=1.5 Volts Corrosion Power Power Plant Steel pipe (-.5V) to Copper (0 V)=.5 Volts Corrosion Power Battery Corrosion cell Dry Cell Battery CARBON ROD (CATHODE) +0.30mV WIRE (METAL PATH) ZINC CASE (ANODE) -1.10mV AMMONIUM and ZINC CHLORIDE (ELECTROLYTE) 11

12 Power Plant Steel and Copper Ground Grid Corrosion Cell Power Plant Steel Piping Copper Ground Grid Special High Risks to Pipelines Containing Hazardous Materials Corrosion Rate Magnified X >100 Times Power plant fuel gas, ammonia and hydrogen piping have increased corrosion rate because of copper ground grid bimetallic coupling inside power plants Natural Gas Transmission Pipelines. Testing required by DOT CFR Title 49 Title 192. (Corrosion risk can be higher than normally expected if shorted to a power plant ground grid) 12

13 Power Plant Corrosion Industrial Congestion Clear Lake, Texas Hog Bayou, Alabama Power Plant Corrosion Hog Bayou EC Outage and Gas Leak 8 years of bi-metallic corrosion Power plant fuel gas piping wall pipe 13

14 RStreng Analysis of addition Corrosion Anomalies DCVG Coating Defect Testing 14

15 DCVG On The Ground Surface above Pipelines Agnews EC, San Jose, CA 15

16 Power Plant Corrosion Agnews EC Outage and Gas Leak 10 years of bi-metallic external corrosion power plant fuel gas piping wall pipe Magic Valley EC CP Design Challenges Plant and Pipeline 16

17 Gas Transmission Pipeline Connected To Power Plant Magic Valley EC East Fuel Gas Transmission Pipeline - Corrosion Damage Two years of bi-metallic external corrosion with CP wall pipe,.047 loss = 14% 17

18 10 Rectifiers Output 40 Amps Each Chlorine Gas 18

19 Chlorine Attacks Anodes Pipes Too Close To Install Insulating Fittings 19

20 Rate of corrosion will be reduced >90% if electrical isolation is achieved. Challenge #3 Electrical Isolation Black Powder Shorts Insulating Flanges Inside Pipelines Sutter EC 20

21 Cathodic Protection All Corrosion of the Metal Will Cease Once the Applied Cathodic Protection Current Equals the Corrosion Current Steel Pipeline Cathode Anode Wire Connection Electrical Current Cathodic Protection Anode Magnesium Galvanic Anodes 21

22 Pipeline Connection Bond Box Challenge #4 - Micro-Biologically Induced Corrosion Rural Area 22

23 Sulfate Reducing Bacteria (SRB) Acid Producing Bactria (APB) How to test for MIC? Feed it and look for growth 23

24 Sulfate Reducing Bacteria(SRB) Limit - 3 Vials, Results 5 Vials Acid Producing Bacteria (APB) Limit - 4 Vials, Results 6 Vials 24

25 Challenge #5 Atmospheric Corrosion Chemical Plants or Salt Water Nearby DOW EC Outage Plant gas piping 20+ years chlorine gas fallout from chemical plant 25

26 SOURCES OF ATMOSPHERIC CORROSION Salt water in the cooling tower Corpus Christi EC SOURCES OF ATMOSPHERIC CORROSION Pasadena EC - Fallout from chemical plants or refineries. 26

27 Weathered Coating And Trapped Rainwater Sherman EC Glycol Piping Challenge #6 Ground Faults and AC Corrosion AC Ground Faults, Steady State Interference- AC Corrosion 27

28 Grounding Devices PCR or OVP OVP Los Medanos EC DOT Required Corrosion Smart Pig Inspection of HCA Gas Transmission Pipeline AC Corrosion Blister After 88 amps already being grounded through 5 devices. Low soil resistivity 28

29 .101 AC Corrosion Anomaly in.500 Wall Pipe 10 years Soil Resistivity is Important 3500 ohm cm = < 3 AC Volts 29

30 AC Corrosion At Third Party Damage To Coating Site DCVG does not work Gas dries soil AC Corrosion at coating damage - 27 AC volts 30

31 Challenge #7 Environmental Liability Bethlehem Fuel Tanks Broad River EC single bottom 120 diameter tank. 31

32 Drilled anode installer SUMMARY CORROSION CONTROL PROGRAM PRIORITIES Safety: Fuel Gas, Ammonia, Hydrogen Protect at any cost Reliability: Cooling water, Instrument air Cost effectiveness Environmental Liability: Aboveground Diesel storage tanks, Underground Storage STP-3 Tanks, Diesel piping. Other Systems: Raw water and demin tanks, water top off piping, gravity drains, boiler blow down. No cathodic protection required: Stainless steel, ductile iron. 32

33 Number Of Gas Fired Plants With Corrosion Related Repairs. 40 Had Repairs To CP or Grounding 12 Have Had No Repairs 2 Have No Cathodic Protection Systems Have Not Yet Been to 14 What Plants Would Have Leaked Without Corrosion Control? Who gets the credit? Riverside EC Hydrogen IF missing Hermiston EC Ammonia anodes Rockgen, GL-2 EC Unclaimed gas piping leak. King City EC Cogen Plant gas isolation and anodes Metcalf, Channel EC - Gas line shorts to ground grid YCEC, FREC Black Powder Shorts 33

34 THE BOTTOM LINE Cost of preventative maintenance VS loss of revenue due to Outages Gross Profit of Average plant (DEC) gross profit margin: $55k/day or $20,075,000/year Cost of corrosion maintenance per year: <$800 to $3000/year Corrosion maintenance as a percent of profit for each plant:.015% The End Questions? 34