A REPORT TO THE BOARD OF COMMISSIONERS OF PUBLIC UTILITIES. Electrical. Mechanical. Civil. Protection & Control. Transmission & Distribution

Transcription

1 A REPORT TO THE BOARD OF COMMISSIONERS OF PUBLIC UTILITIES cpwlpy SIGNA Z2L LAND Electrical Mechanical Civil Protection & Control Transmission & Distribution Telecontro I System Planning REPLACE FUEL OIL HEAT TRACING Holyrood Thermal Generating Station Ju'y 2011 newfoundland labrador hydro a nakor energy company

2 Table of Contents 1 INTRODUCTION PROJECT DESCRIPTION EXISTING SYSTEM Age of Equipment or System Major Work and/or Upgrades Anticipated Useful life Maintenance History Outage Statistics Industry Experience Maintenance or Support Arrangements Vendor Recommendations Availability of Replacement Parts Safety Performance Environmental Performance Operating Regime JUSTIFICATION Net Present Value Levelized Cost of Energy Cost Benefit Analysis Legislative or Regulatory Requirements Historical Information Forecast Customer Growth Energy Efficiency Benefits Losses during Construction Status Quo Alternatives CONCLUSION Budget Estimate Project Schedule APPENDIX A... A1 APPENDIX B... B1 APPENDIX C... C1 APPENDIX D... D1 APPENDIX E... E1 APPENDIX F... F1 i

3 1 INTRODUCTION The Holyrood Thermal Generating Station (Holyrood) is an essential part of Newfoundland and Labrador s generating system, delivering electrical energy to retail, industrial, and residential customers. This plant has three generating units producing a total capacity of 490 MW. The plant was constructed in two stages. Stage 1 was commissioned in 1971 bringing on line generating Units 1 and 2, each rated at 150 MW. Stage 2 was commissioned in 1979 bringing on line generating Unit 3 also rated at 150 MW. In 1988 and 1989, the generation capacity of Units 1 and 2 was increased to 175 MW each. Holyrood has the capacity of generating over 3,000,000 MWh of energy annually which is approximately 40 percent of the Island Interconnected System s energy requirement. Figure 1: Holyrood Thermal Generating Station At this plant, Bunker C fuel oil is burned in large oil burning furnaces, converting water to steam which is then used to propel turbine generators. A 455 mm diameter insulated pipe, equipped with electric heat tracing was installed as part of the original construction and is used to transport Bunker C Fuel Oil from the marine terminal to the facility s fuel storage Page 1

4 tanks approximately 1200 m away. The 455 mm diameter pipeline is divided into two subsections at approximately the midpoint of the pipeline. Each subsection of pipeline consists of separate heat tracing circuits, designated as North Section and South Section. In addition, there is a section of 100 mm diameter pipeline, approximately 100 m in length, which also requires replacement of heat tracing cable. During the period from September to April, shuttle tankers arrive at the marine terminal and Bunker C fuel oil is pumped through the 455 mm diameter insulated pipeline to the tank farm. Before the shuttle tanker attempts to pump oil into the pipeline, the oil is heated to approximately 60 O C onboard the tanker. Because of the thick nature of this oil, to successfully transport oil through the pipe the oil temperature must be maintained at a minimum of 30 O C throughout its path of flow. To maintain an oil temperature of 30 O C throughout the pipe, an oil heating system known as electric heat tracing (EHT) is installed along the full length of the pipe. The main component of EHT is the copper conductor which is heated by the flow of electric current produced by three phase 600 volt power supply. Figure 2 shows a picture of the existing 455 mm fuel oil pipeline equipped with electric heat tracing in Holyrood. Page 2

5 Figure 2: Electric Heat Tracing Page 3

6 2 PROJECT DESCRIPTION This project is required to replace the electric heat tracing (EHT) on the fuel oil pipeline at the Holyrood Thermal Generating Station. The existing heat tracing cables have deteriorated and have resulted in various problems with the performance of the existing application, including failed sections of heat tracing due to open circuits and ground faults. This two year project also includes the replacement of fiberglass insulation and metal cladding for the entire pipeline. The scope of work includes: Erection of scaffolding for the shore arm and three expansion joints on the 455 mm diameter line Removal of existing insulation, metal cladding and mineral insulated heating cables Testing of 455 mm diameter pipe thickness at prescribed intervals Coating of 455 mm diameter pipe for corrosion protection Installation of the new electric heat tracing system Installation of new insulation and cladding Installation of programmable controller with self diagnostics Construction Management Commissioning of the new system Disposal of existing metal cladding, insulation, and heat tracing cable An external contractor will be required to install the new system. Based on discussions with the original equipment manufacturer (OEM), Tyco Thermals Controls, of the existing heat tracing system, it is anticipated that the existing copper heat tracing cable will need to be replaced with a stainless steel heat tracing cable. Stainless steel heat tracing cables offer better corrosion resistance than copper heat tracing, making it more suitable for this application. Page 4

7 It will take approximately four to six months to complete replacement of the entire heat tracing system. Hydro proposes to complete the work in two sections the South Section and 100 mm diameter pipeline to be completed in the summer of 2012 and the North Section to be completed in the summer of Each section takes approximately two to three months to complete. Page 5

8 3 EXISTING SYSTEM The electric heat tracing equipped on the fuel oil pipeline consists of a High Density Polyethylene (HDPE), copper sheathed, mineral insulated (MI) electric heat tracing cable. These cables are strapped to the fuel oil pipe line every three to five linear feet intervals. They are then insulated with two inches of fiberglass insulation and then wrapped with metal cladding as shown in Figure 3. Figure 3: Cross Section of 18 (455 mm) Pipeline The 455 mm diameter fuel oil pipeline heat tracing consists of two main electric circuits, North Section and South Section, both of which are approximately 600 meters in length. Each section of pipeline is then subdivided by heat tracing cable lengths of approximately 50 meters. The North Section runs from the facility tank farm to the midpoint of the pipeline, and the South Section runs from the marine terminal to the midpoint of the pipeline. The 100 mm diameter pipeline runs from the marine terminal to approximately three meters past the control valve located near the base of the shore arm. The shore arm is a cement structure extending approximately 100 m from the shoreline into the ocean to support a marine terminal at water depths which allow shuttle tankers to dock and un-load fuel oil. The purpose of this pipeline is to drain a section of 455 mm diameter pipeline from the marine terminal to the control valve. This is done so that if ice were to damage the 455 mm diameter pipeline on the shore arm, the pipeline would be empty of fuel and no oil Page 6

9 would be released into the environment. The shore arm is shown in Figure 4. Figure 4: Shore Arm Please refer to Appendix A for a layout drawing of the existing fuel oil pipeline. From 2004 to 2011, repetitive failures of the existing heat tracing cables have occurred due to ground faults and open circuits. As a result, attempts to pump oil through the pipeline have failed because the oil could not be maintained at the required temperature for oil flow. Page 7

10 The existing heat tracing system was newly installed in 2002 to replace the original bare copper mineral insulated electric heat tracing. Since 2002, the high density polyethylene jacket has melted off and the cable is failing prematurely. Over time, moisture has accumulated within the insulation, and has caused corrosion of the copper sheath of the cable. The moisture seeps through the outer copper sheath and causes system failure by creating open electric circuits and ground faults. As a result, in 2009, the original three phase system was modified into a two phase system in order for the system to remain operational. This system operates on a continuous basis due to the lack of confidence that the system will re-energize once turned off. Figures 5 and 6 show pictures of the deteriorated heat tracing cables. Figure 5: Deteriorated Heat Tracing Cable Page 8

11 Figure 6: Deteriorated Heat Tracing Cable Also, the existing heat tracing application on the 100 mm diameter pipeline has experienced similar problems as the main pipeline. It consists of bare copper mineral insulated heat tracing cables which were installed during original construction and has exceeded its useful service life. Over the years moisture has accumulated within the insulation and corroded the copper sheath, resulting in open electric circuits and ground faults and thus, failure to heat the oil. Figure 7 shows a picture of the existing electric heat tracing cable on the 100 mm diameter fuel oil pipeline. Page 9

12 Figure 7: Deteriorated Heat Tracing Cable The condition of the existing heat tracing cables on the 455 mm diameter and 100 mm diameter pipes place the environment, worker safety and system reliability at risk. 3.1 Age of Equipment or System The heat tracing system on both the North and South section of the 455 mm diameter pipeline replaced the original in It has been in operation for nine years. The 100 mm diameter pipeline was installed during original construction and has been in operation for 40 years. 3.2 Major Work and/or Upgrades In 2002, the original bare copper electric heat tracing cable on the South Section and North Section was replaced with a new copper sheathed mineral insulated electric heat tracing cable, equipped with a high density polyethylene jacket. Page 10

13 Tyco Thermal Controls (TTC) is the Original Equipment Manufacturer (OEM) for the electric heat tracing installed during original construction, and for the new replacement cable installed in From 2004 to 2011, repetitive failures have been experienced with the cables on both the North and South Sections of EHT cable which was installed new in As a result, Hydro operations personnel modified the three phase electric heating system into a two phase system to mitigate sections of deteriorated heat tracing cable. This modification was required for the electric heating system to remain operational, and is a temporary measure until replacement of the entire electric heat tracing system occurs. The procedure of eliminating an electrical phase, or "making two phases into one" allowed reenergization of the heat trace during critical operational periods in the winter months. The trade off for this is essentially double the rated electrical current flowing through sections of the heat trace system. This shortens the life of the remaining sections of heat trace. Given the total length of the fuel oil piping a proper design requires three individual electrical phases, each equally sharing a component of the total heat trace system. In September 2009, Hydro contracted the OEM of the existing heat tracing cables to provide an analysis and opinion to determine the cause of the premature failure of the electric heat tracing cable installed in TTC discovered that the HDPE jacketed copper MI cables had been installed in place of bare copper MI cables. The following is a quote from Page 2 from the TTC Report dated March 31, 2011: There are two problems associated with using the jacketed cable for this installation. The first is that the 26.7 watts/ft output of the heater exceeds our maximum recommendation of 8-9 watts/ft for jacketed copper MI cables on metal pipes. The second is that the sheath temperature for these heaters would be in excess of 405 o F and this exceeds the recommended maximum continuous operating temperature for HDPE of 248 o F. Please refer to Appendix B for more information. Also, early in 2011, an internal root cause failure analysis was completed to determine the Page 11

14 reasoning behind the decision to choose the electric heat tracing cable currently installed on the North and South section of the fuel oil pipeline. Please refer to Appendix C. 3.3 Anticipated Useful life The anticipated useful life of copper heat tracing cable is 20 years. However, this may vary depending on environmental and service conditions. 3.4 Maintenance History The five year maintenance history for the Holyrood Thermal Generating Station electric heat tracing system is shown in Table 1. Year Table 1: Five Year Maintenance History Corrective Corrective Maintenance (CM) Maintenance ($000) Three CM work orders on malfunctioning of EHT One CM work order on malfunctioning of EHT Four CM work orders on malfunctioning of EHT. 3 phase system modified to a 2 phase system Five CM work orders on malfunctioning of EHT One CM work order on malfunctioning of EHT Preventive maintenance of the heat tracing system is a component of the annual maintenance strategy of the fuel oil delivery system. Hydro does not track heat tracing preventive maintenance costs separately from the total unit maintenance cost. As a result, specific preventive maintenance costs for the heat tracing system are not available. Page 12

15 3.5 Outage Statistics No outages have been attributed to failed electric heat tracing at Holyrood. 3.6 Industry Experience Curtiss Wright, Scientech, is experiencing similar problems such as ground faults and circuit failures with bare copper electric heat tracing. The outer copper sheath of the heat tracing cable reacts to the original pipe insulating material, attacking the outer sheath. Over time, moisture seeps through the outer sheath and causes electrical ground faults resulting in failure of the electric heat tracing. Please refer to Appendix D. 3.7 Maintenance or Support Arrangements All maintenance work is performed by Hydro operations personnel. 3.8 Vendor Recommendations TTC recommends replacement of the entire existing copper heat tracing system with stainless steel heat tracing. Copper heat tracing is not suitable for this application because of the moisture levels and sea salt spray experienced in Holyrood. Please refer to Appendix E. 3.9 Availability of Replacement Parts Replacement heat tracing cables are readily available within three to four weeks of an order. Page 13

16 3.10 Safety Performance The existing heat tracing cables have deteriorated resulting in safety hazards from potentially failing equipment. Improper functioning of the heat tracing is a serious concern to the safety of operations personnel when shuttle tankers attempt to pump Bunker C fuel oil from the marine terminal to Holyrood s facility tank farm. For successful pumping of oil through the pipe to the tank farm, the oil must be maintained at a temperature of 30 O C. Improper functioning heat tracing cannot achieve this temperature. As a result, as the tanker attempts to pump cooled oil (<30 O C) through the pipe, there is the possibility for build-up of excessive back pressure in the pipeline at the marine terminal. Excessive pressure can result in damaging the pipeline, leading to spillage of hot Bunker C fuel oil, potentially causing severe burns or a fatality Environmental Performance The environmental concern present with the condition of the existing heat tracing system is the potential release of a large volume of bunker C fuel oil into the environment. As mentioned earlier, a shuttle tanker attempting to pump oil through the pipeline at a maintained temperature lower than 30 O C, can potentially result in excessive back pressure in the line, bursting the pipe, leading to spillage of Bunker C fuel oil into the Atlantic Ocean. Page 14

17 Figure 8: 455 mm Pipeline Spillage of Bunker C oil presents serious concern. The release of oil would result in contamination of the Atlantic Ocean, detrimentally impacting highly populated plant and marine life. It should also be noted that a nearby public beach would be negatively impacted as well. Bunker C oil is very thick and sticky, and has been found to float, sink, or do both in water 1. Bunker C oil properties make it very difficult to treat and clean up when it comes in contact with the environment. Clean up of an oil spill of approximately 15,000 barrels would not only require great effort, but will be very costly as an extensive amount of resources will be required to clean up oil from the ocean and shoreline. It was estimated that a minimum cost to clean up an oil spill into the Atlantic Ocean is approximately $1,000, Page 15

18 Figure 9 shows a picture of the beach and surrounding area near the Holyrood Thermal Plant. Figure 9: Holyrood Image taken from Page 16

19 Figure 10 below is a picture of a bunker oil spill in San Francisco. Figure 10: Bunker Oil Spill in San Francisco Image taken from Operating Regime Currently, the remaining two phases of heat tracing is in continuous operation because of the lack of confidence the system will work again if turned off. Operations personnel believe the existing system has deteriorated to the point that if they de-energize the cables for any period of time, they will not re-energize when turned back on. The new proposed installation will allow for the heat tracing system to be switched off during summer months through the installation of a programmable controller. Seasonal operation will reduce the total power consumed by approximately 50% of the total power consumed by the existing system. Page 17

20 4 JUSTIFICATION This project is justified on the requirement to replace the deteriorated electric heat tracing system based on safety, operational reliability, and the environment. Due to the highly corrosive environment that this heat tracing system is exposed to, an anti-corrosive material is required. The previous installation used a copper sheathed material with a HDPE jacket. This jacket did not withstand the temperatures it was exposed to and melted. Stainless steel is the most economic material that will withstand both corrosion and the required temperatures. The project is required based on the following reasons: 1. Failure to Receive Oil The storage of Bunker C fuel oil has to be maintained at sufficient levels in the tank farm to ensure continuous operation of the Holyrood Generating Station. Electric heat tracing of the entire length of piping heats the highly viscous oil to enable pumping from shuttle tankers to the facility tank farm. The existing electric heat tracing system has deteriorated and is now temporarily repaired for unloading oil from the tankers. On February 22, 2011, a tanker could not deliver fuel for three days due to failed electric heat tracing, resulting in three days of demurrage payments of $18,000 to $25,000 per day. 2. Consultant Recommendations A consultant, AMEC completed a condition assessment and advised Hydro that the system should be replaced as indicated in the following quote from Page 1 of their condition assessment report: The heavy oil electrical trace heating system on the pipeline from the dock to the receiving point at the south end of the tank farm was replaced but has recently experienced failures. The plant has managed to get two phases back in working order, but the failure of these phases is very likely. This issue needs to be resolved and the system replaced. See Appendix F. Page 18

21 3. OEM Recommendations The OEM, Tyco Thermal Controls, has recommended that the existing copper heat tracing system be replaced with new stainless steel electric heat tracing. 4. Personnel Safety The insulation of the cables of the existing heat trace system has become brittle. This reduces the ability of the insulation to protect from electric ground faults and the insulation resistance has become lower than the acceptable minimum value. The deterioration of the insulation indicates that there are places where there are leakage currents which endanger the safety of personnel. 5. Environmental Performance Release of Bunker C oil into the Atlantic Ocean is a serious environmental concern, and presents a high risk of severely impacting an environment which is highly populated with plant and marine life. The pipeline has the capacity to contain approximately 15,000 barrels of oil. This risk is significantly reduced with the installation of a new heat tracing cable suitable for this application. Failure to replace the existing heat tracing cables increases the likelihood of failure to receive fuel oil and could lead to extensive equipment damage, and poses serious risk to personnel safety, the environment and operational reliability. 4.1 Net Present Value A net present value calculation was not performed in this instance as only one viable alternative exists. Page 19

22 4.2 Levelized Cost of Energy This project will not affect the levelized cost of energy for the system. 4.3 Cost Benefit Analysis A cost benefit analysis is not required for this project proposal as there are no quantifiable benefits. 4.4 Legislative or Regulatory Requirements There are no legislative or regulatory requirements associated with this project. 4.5 Historical Information In 2002, the original copper MI heat tracing cables on the fuel oil delivery pipeline was replaced with new jacketed copper MI heat tracing cables. Please refer to Appendices B and C. 4.6 Forecast Customer Growth This project has no effect on forecasted customer growth. Figures 11 and 12 below show the fuel quantity forecast required to meet the load forecast. Page 20

23 Figure 11: Island Interconnected Peak Demand to be supplied to Holyrood Figure 12: Holyrood Plant Fuel Forecast 4.7 Energy Efficiency Benefits There are no energy efficiency benefits associated with replacement of the existing copper electrical heat tracing system with stainless steel heat tracing. Page 21

24 4.8 Losses during Construction There are no losses anticipated to occur during construction of this project as the replacement will be performed during the period from May 1 to August 31 when no oil is delivered to Holyrood. 4.9 Status Quo The status quo is not an acceptable alternative because the deteriorated and obsolete equipment poses safety hazards to Hydro operations personnel and poses risk to the environment and reliable delivery of service to customers Alternatives Electric heat tracing is the only viable option to the problems described. Page 22

25 5 CONCLUSION The replacement of the fuel oil heat tracing system is justified on the basis of the safety and environmental concerns and the unreliability of the existing equipment to operate properly. Without the replacement, operating staff, the environment, and system reliability are exposed to unacceptable risks associated with failure of the heat tracing cable. To eliminate known safety, reliability and environmental risks, the entire heat tracing system on the fuel oil pipeline requires replacement. 5.1 Budget Estimate The budget estimate for this project is shown in Table 2. Table 2: Budget Estimate Project Cost:($ x1,000) Beyond Total Material Supply Labour Consultant Contract Work 1, ,944.0 Other Direct Costs Interest and Escalation Contingency TOTAL 1, , ,888.2 Page 23

26 5.2 Project Schedule The work is scheduled over a two year period and will be completed during the period from May through August when no fuel oil is delivered to site. The anticipated project schedule is shown in Table 3. Table 3: Project Schedule Activity Start Date End Date Planning Initial Project Planning Jan 2012 Mar 2012 Design Transmittal Development Design Equipment Tenders Placement of Orders Detailed Design Engineering Mar 2012 Apr 2012 Procurement Equipment Delivery Apr 2012 May 2012 Construction Equipment Installations South Section Equipment Installations North Section Equipment Retirement May 2012 May 2013 Aug 2012 Aug 2013 Commissioning Equipment in Service South Section Equipment in Service North Section Sep 2012 Sep 2013 Sep 2012 Sep 2013 Closeout Project Completion and Closeout Dec 2013 Dec 2013 Page 24

27 Page 25

28 Appendix A APPENDIX A Fuel Oil Delivery Line Heat Trace A1

29 Appendix A A2

30 Appendix B Appendix B Tyco Thermal Controls Holyrood Heat Tracing Background Information B1

31 Appendix B March 31, 2011 Newfoundland Labrador Hydro Holyrood, NL A0A 2R0 Attention: Christian Thangasamy, M.Eng., P. Eng. Reference: EHT system on the 18 inch Fuel Oil Line Background Information Christian, The following represents a summary of the Tyco Thermal Controls (TTC) electric heat tracing (EHT) system installed on the 18 inch fuel oil line at the Holyrood Generating Facility. The original installation was done in February The construction drawings show that the 4000 foot line was divided into two circuits at approximately the mid-point of the pipeline. The circuits were designated as North (ccts 1A to 1E) and South (ccts 2A-2D). The mineral insulated heating cable was Pyrotenax reference R12C: single conductor, 600 volt, bare copper, 14 watts/linear foot. The system operated as designed for approximately 30 years until 2000 when repair work began. TTC provided a budget to replace the heat tracing in December 2000 offering 3 options: selfregulating heating cables, mineral insulated heating cables or STS (skin effect). It was suggested at this time to change the mineral insulated cables to stainless steel. Alloy 825 heating cables have a higher operating temperature range and offer better corrosion resistance than copper jacketed cables. In May 2002 another proposal was submitted offering 2 options: replace all or a part of the MI heating cable with new MI cables or install a complete new system with self-regulating heaters. It is our understanding that, for budget considerations, only a few of the heating cables were replaced on the North circuit. TTC introduced new cable reference numbers B2

32 Appendix B effective March 17, 1997 and the original R12C cable reference was changed to the new reference 61CC5162. This reference is a copper MI cable. On May 23, 2002 Tyco sent a letter to Newfoundland Hydro summarizing the existing EHT system. Over the past number of years many significant changes had been made to the system. Existing circuits 1B, 1D and 1E were not operating. Circuit 1B was taken out of service and teck cable was installed as a jumper. This would reduce the overall resistance in the circuit and increase the power output and sheath temperature of the remaining cables. NL Hydro request made to provide a new design to install 6 each 150 foot MI cables series connected to the 3 each 366 foot cables of circuit 1A. At some time in 2003 Newfoundland Hydro would reconnect ½ of circuit 1D and all of circuit 1E. By connecting the MI cables as detailed above, the copper heating cables would be operating at 41 volts, producing 26.7 watts/ft and having a sheath temperature of approximately 407 deg. F. It was noted that TTC normally limits the sheath temperature of copper cables to 392 deg. F. TTC was not made aware of whether or not circuit 1D and 1E were ever reconnected. Also, it is not clear if or when the teck cable was replaced by heating cable. In September 2009 TTC reviewed this installation again. Insulation was removed to check the condition of the heater in different sections of the pipe. At this time it was discovered that HDPE jacketed copper MI (B61CH5162/ ) had been installed in place of bare copper (B61CC5162/ ) during the retrofits.there are two problems associated with using the jacketed cable for this installation. The first is that the 26.7 watts/ft output of the heater exceeds our maximum recommendation of 8-9 watts/ft for jacketed copper MI cables on metal pipes. The second is that the sheath temperature for these heaters would be in excess of 405 deg. F and this exceeds the recommended maximum continuous operating temperature for HDPE of 248 deg. F. During the visual inspection of the heater it was found that the jacket had melted off of the copper heating cable which would be expected based on the calculated sheath temperature. It appears that an incorrect purchase requisition may have been issued for jacketed copper heating cable. While the HDPE jacket would be damaged due to temperature, the copper MI cable would still operate. The copper cable, without the HDPE jacket, may have been subject to increased corrosion. Later in September TTC sent their field service representative to site to inspect the system and fault locate many of the cables. Many of the circuits were found to be open or grounded. A report was submitted outlining the necessary steps to repair some of the B3

33 Appendix B cables. The field service rep returned in October to carry out some of the repairs to the cables. The system today operates with only 2 of the phases working. In general, TTC electric heat tracing systems have a 10-year warranty and an expected life in excess of 20 years. This assumes that the EHT system, which includes not only the heat tracing cables and controls but also the insulation, cladding and distribution wiring, is properly maintained. The existing system appears to have worked for almost 30 years. When repairs were undertaken it seems that, to meet budget constraints, compromises were made to the system. As this is a resistance heating system, changes made to some sections of the circuit design (1A to 1E) caused other heating cables in the circuit to operate at wattages, currents or temperatures exceeding their recommended design limits. Please call me if you have any questions concerning this information. Regards, Pete Inglis Regional Manager Tyco Thermal Controls 3 Kingslea Gardens Toronto, ON M8Y 2A7 Phone: B4

34 Appendix C Appendix C Root Cause Failure Analysis of Electric Heat Tracing C1

35 Appendix C Table of Contents Root Cause Failure Analysis of Electric Heat Tracing page 1 Appendix 1 Appendix 2 Appendix 3 Appendix 4 Appendix 5 Appendix 6 Appendix 7 Appendix 8 Appendix 9 Appendix 10 Appendix 11 Appendix 12 Tanker Report Acceptance form for offloading oil tankers Discharge Pressure Log Pumping Log Canadian Maritime Agency Statements of Facts Tyco s Inspection Report Copy of Cable Tag Copy Tyco Specification Sheet for Copper MI Cables Copy of Purchase Order Requisition for Copper Sheathed Cable Copy of the Quote for 12w/ft copper sheathed cables from vendor with the words PVC jacket Copy of P.O. #40043 OP dated 03/02/17 for R12C Copy of the Vendor s fax dated May 23, 2002 informing delivery time and price for copper sheathed cables C2

36 Appendix C HOLYROOD THERMAL GENERATING STATION INCIDENT REPORT Root Cause Failure Analysis of Electric Heat Tracing Marine Terminal to Tank Farm 18 inch Bunker C oil Piping Date of incident: 19 February 2011 Date of start of investigation: 14 March 2011 Date of final report: 31 March 2011 Incident Cost: $ 100,000 Incident Summary: The Holyrood Thermal Generating Station burns Bunker C oil as fuel in the burners. Bunker C oil is stored in four tanks on site for its daily use. These tanks are filled by Bunker C oil brought by ocean going tankers. These tankers berth at the plant s marine terminal which is at a distance of 4000 feet from tank # 1 which is the farthest tank. The oil from the tankers is pumped through 18 inch piping. Bunker C oil being very viscous needs to be maintained at approximately 30 0 C by means of either electrical or steam tracing the piping for pumping. At Holyrood the 18 inch pipe is provided with electrical heat tracing. Every year the plant receives between five and ten oil tankers. On 14 th February a tanker arrived at St John s pilot station and it was ready to discharge oil on 19th February. The oil could not be pumped for three days due the failure of the electric heat tracing on the 18 inch 4000 feet long pipe. This resulted in a demurrage payment for three days. Initial Conditions: The electric heat tracing was on. It had not tripped. Initiating Event: When commencing to pump from the tanker the pressure was increasing indicating a block in the discharge piping. The flow meter in the ship did not show any indication of oil flow. Incident Description: On 19 th February, mechanics went to the dock to discharge oil from the tank. The loading arms were connected at 1410 hrs. Mechanics commenced pumping at 1530 hrs. The pump discharge pressure remained at 400 kpa until 1800 hrs. The flow meter at the tanker did not show any flow C3

37 Appendix C except for the 137 barrels which is the volume of the empty 18 inch piping from the dock to the block valve at dock gate. This portion of the piping is drained after discharging the oil from tankers by means of 4 inch drain piping. It was found that the electric heat tracing had malfunctioned. The Shift Supervisor raised an emergency work order on 20 th February for electricians to attend to the defective electric heat tracing. The present electric heat tracing was commissioned in In 2000, Tyco, the manufacturer of the electric heat tracing submitted a proposal to Hydro for replacement the 30 year old electric heat tracing system. The original heat tracing cables were copper sheathed with part number R12C150. The letter C is for copper sheathed, the number 150 is for the length of the heating cable in feet and the number 12 is the size of the cable in wire gauge. Tyco s options in 2000 were: 1. Self Regulating Heating Cables $1,122, Mineral Insulated Inconel Sheathed Heating Cables $879, Skin Effect Heat Tracing System $710, Tyco included the option of stainless steel sheathed cable heaters. However, in 2002, Hydro did not opt for any of the above when the project for replacement of the Heat Tracing started. Hydro did not have a budget to afford any of the above options. Hence Hydro planned to replace the defective copper sheathed heater cables, by the plant forces over a two/four year period to preserve budget. Tyco carried out the design calculations for copper sheathed heater cables. The sheath temperature was calculated to be C. The watts/ft was 12. Hydro contemplated replacing the copper sheathed mineral insulated heater cables with self regulating cables. Tyco informed Hydro that the cost of self regulated cables would be $84,000 and that of copper sheathed mineral filled heater cables as $18,000. Hydro opted for the copper sheathed mineral filled heater cables in view of the lower cost as well as costs associated with new 208 V step down transformers required for the self regulating heater cables. The plant decided to have the copper sheathed heater cables to be jacketed with High Density Polyethylene to protect the copper sheath from corrosion. Plant electricians began installing High Density Polyethylene jacketed copper sheathed mineral cables during Oct The allowable maximum temperature for High Density Polyethylene is C. The maximum allowable wattage for High Density Polyethylene jacketed heater cable is 8 watts per foot. Hydro did not change the heater cable length to suit the lowered wattage loading. The electric heat tracing project was completed on 12 th November 2004 at a cost of $231,698. The heat tracing began to fail from It was observed that the HDPE was cracking and melting. The heater cable was getting overheated and grounding out due to loss of insulation. In Nov 2009, the heat tracing system had to be modified to a two phase system from 3 phases due to excessive C4

38 Appendix C grounding in one phase. There were 19 corrective maintenance work orders between Nov 2004 and 19th Feb Immediate Corrective Action: The electricians found that the electric heat tracing was ON with a section halfway between the railway crossing and the dock gate, open circuited. The terminations of the cold leads to the defective section had to be drilled as they had fused to their brass terminals at the terminal box. The defective section was by-passed by energizing an unused section of a phase which had been taken out of service in Causes & Corrective Actions: The decision by the Plant to go for High Density Polyethylene jacketed heater cables contributed to the failure of the heat tracing system. As per Tyco, the HDPE jacketed cables are designed and used as snow melting cables. These cables are used for corrosive embedded applications such as asphalt or snow melting where the HDPE can dissipate heat over a large area. When the HDPE jacketed heater cable is wrapped on a pipe, it has only a finite area of contact thus limiting the area for heat transfer. The wattage loading is 8 watts per foot for the high density polyethylene jacketed cables. The plant purchased HDPE jacketed heaters for a system which was designed for copper sheathed cables with a load of 12 watts per foot. The tags on the cables on the 18 inch fuel oil piping show 150 feet and 1800 watts. Thus High Density Polyethylene cable heaters which were designed for a maximum load of 8 watts/foot were subjected to a load of 12 watt/foot. The HDPE jacketed cables have therefore been subjected to excessive overheating and broke down. The copper core burnt out due to higher than design wattage causing the break down of the copper sheath resulting in cable failure. The resistance measured on the system has repetitively been lower than the allowable value of 1.6 meg ohm. The following accelerated the breakdown of the heat tracing system. 1. The moisture ingress through defective sealing in the cladding which provided a source for grounding. 2. Tech cables which were installed to by pass defective circuits decreased the resistance in the heater cables and thereby increased the power in the cables resulting in overheating. Weekly measuring of the resistance in the circuits has been initiated as a condition monitoring strategy. Lessons Learned: C5

39 Appendix C 1. When changing the material composition of a component, thorough research has to be done on the applicability of the new material. 2. When replacing a component in an existing system, the new component must be checked whether it conforms to the specifications of the existing system. 3. Prior to commissioning a project, the function of the system and components in the system should be thoroughly understood by calling for meetings and discussions with end users/vendors. 4. When budget is not available, more Preventive Maintenance needs to be carried out to keep the system in operation and efforts to expedite the budget approval process should be made rather than trying to fit the project to the available budget. C6

40 Appendix C Appendix 1 C7

41 Appendix C C8

42 Appendix C Appendix 2 C9

43 Appendix C Appendix 3 C10

44 Appendix C C11

45 Appendix C Appendix 4 C12

46 Appendix C Appendix 5 C13

47 Appendix C C14

48 Appendix C Appendix 6 C15

49 Appendix C C16

50 Appendix C Appendix 7 C17

51 Appendix C Appendix 8 C18

52 Appendix C Appendix 9 C19

53 Appendix C Appendix 10 C20

54 Appendix C Appendix 11 C21

55 Appendix C Appendix 12 C22

56 Appendix D Appendix D Fossil Operations & Maintenance Information Service Above Ground Fuel Line Heat Tracing Cable D1

57 Appendix D D2

58 Appendix D D3

59 Appendix E Appendix E Fuel Lines Engineering, Procurement and Construction (EPC) Services E1

60 Appendix E E2

61 Appendix E E3

62 Appendix E E4

63 Appendix E E5

64 Appendix E E6

65 Appendix E E7

66 Appendix E E8

67 Appendix F APPENDIX F AMEC Condition Assessment & Life Extension Study F1

68 Appendix F F2