STEAM PLANT AUTOMATION WITH BRIDGE CONTROL ON SELF-UNLOADING BULK CARRIER CASON J. CALLAWAY

Transcription

1 STEAM PLANT AUTOMATION WITH BRIDGE CONTROL ON SELF-UNLOADING BULK CARRIER CASON J. CALLAWAY Presented to the Spring meeting of the Great Lakes/ Great Rivers Section of SNAME May 17, 2002 Gary R. Bowler, 1 member; John C. Hartman, 2 visitor; James D. Sharrow, PE, 3 member; and John F. Thibodeau, 4 member The Steamer Cason J. Callaway is a typical Great Lakes self-unloading bulk vessel, originally constructed in During its life, the vessel has undergone several significant alterations, principally lengthening of the hull by 120 in 1974, boiler automation in 1972 and conversion to self-unloader in Due principally to its operation solely on the Great Lakes, the hull was considered to be in excellent condition in the year However, the lack of process control equipment installed at that time kept manning at a relatively high level of 26. Re-powering with a modern medium speed diesel plant was considered. This would have permitted a considerable reduction in crew size with nearly a 50% reduction in fuel consumption. However, the capital cost of such an arrangement was considered by the owners to be cost-prohibitive. As an alternative to re-powering, the automation of engine room and control functions was accomplished. This paper describes the design, programming and installation of a state -of the-art fully redundant process control, monitoring and alarm system on the vessel. The system features full bridge control of the throttle in place of the historic Chadburn Engine Order Telegraph (EOT) system. The ballast manifolds in the engine room were replaced by an arrangement that permitted remote, automated operation. The US Coast Guard certified the vessel for minimal manning which reduced engine room watch standers from 2 to 1 per watch. Three unlicensed crew positions were eliminated, and total crew size now numbers 23. Description of vessel The Cason J. Callaway is one of 3 sister vessels owned by Great Lakes Fleet of Duluth, Minnesota. In all, 5 vessels were constructed within this class, all of which still operate on the Great Lakes. A total of 22 other U. S. flag and 15 Canadian flag steamers exist on the Great Lakes. Two of the U.S. vessels were never converted to self-unloaders and remain in long-term lay-up. An additional two other vessels have steam reciprocating engines and are of an age that likely disqualifies them from possible consideration for similar automation projects. This leaves thirty three (33) other possible candidates for employment of the technology installed in 2001 on the Callaway. 1 President, G. R. Bowler, Inc. 2 Associate, G.R. Bowler, Inc. 3 President, J. D. Sharrow and Associates, Inc. 4 Port Engineer, Great Lakes Fleet, Inc. 1

2 Particulars of Cason J. Callaway Official Number Builder Year delivered 1952 Hull number 297 Length Over-All Beam 70-0 Depth 36-0 Great Lakes Engineering Works, River Rouge, MI Hull #297 Propulsion Boilers 7000 SHP Westinghouse cross compound turbines Double reduction gear; single fixed pitch propeller 2- Foster Wheeler, 39,000 lb/hr 550 PSI, 489 PSI & 766 degrees F. superheat Unloading equipment Stephens Adamson, rated at 6000 long tons/hour Installed in 1982, with a 262 swing boom Generators (ship 2- General Electric 400 KW, 440V 3 Phase service) Generators 2- Caterpillar D399, 800 KW, 440 V 3 Phase (unloading) Method of control prior to this project Before this project was undertaken, all propeller commands were registered by the Master via the original Chadburn Engine Order Telegraphs (EOT) that was delivered with the ship in A watch standing engineer was required to be available to acknowledge and respond to these EOT commands, and needed to be stationed at the throttle valves while maneuvering. Revolutions of the fixed pitch propeller were controlled by the watch standing engineer by opening, closing and adjusting the manual throttle valves. Watch standing Oilers were required by the U. S. Coast Guard Original manual throttle stand Certificate of Inspection to assist in the engine room, and made rounds several times each watch to record the information displayed by the dozens of manual gauges that monitored temperature and pressure of most equipment in the 2

3 engine room. These activities were very similar to all steam powered vessels built in the early 1950s. Burner management, feed water control and combustion control were handled by a John Zinc control system installed in the early 1970s and updated by Buchanan Industries in Ballast level gauging in the engine room was indicated by a mercury manometer type King Gage system, read manually by the Oiler. Ballast tank valves were manually opened and closed on the original ballast system manifolds within the engine room. There were separate valves for pumping in and out of each tank. This meant a total of 36 valves for the 18 ballast tanks. Eight of the ten engine department employees worked within the engine room almost exclusively. The First Assistant would split his hours between the engine room and other areas of the ship as needed, and the Handyman worked almost exclusively out of the engine room. Problems identified with original control system: The John Zink controls were nearly 30 years old and in need of re-placement. The Buchanan upgrade performed in 1995 was incompletely documented and failed to solve the problems associated with the aging John Zink equipment. Continuing problems included poor control at low load levels, poor combustion efficiency, smoke, excessive carbon build up in flues, poor water level control, obsolete and unserviceable equipment. Competitive pressures on Great Lakes shipping encouraged the reduction of staff required to operate the vessel. Owner s requirements The owner wanted to replace the existing control system with one that would: 1. Replace all prior control logic at a centralized location. 2. Enable full bridge control of the throttle. 3. Eliminate the watch standing Oiler position by automating most of the Oiler s on-watch duties. This required a change in the USCG Certificate of Inspection required manning. 4. Maximize combustion efficiency. 5. Minimize electrical consumption of auxiliaries. 6. Minimize carbon build up within flues. 7. Enable centralized, remote control of ballast system. 8. Replace obsolescent electrical switch gear. 9. Minimize use of analog gauges in favor of computer monitors. 10. Simplify and minimize problems with trouble shooting 11. Provide automated and complete trending of operational characteristics. 12. Supplement existing emergency generator with an auto start diesel unit within the engine room that could parallel with an existing turbo-generator to maintain operation of all systems in the event of a failure of a turbo generator. This unit also was required for complete start-up of the steam plant from a dead ship condition. 3

4 G.R. Bowler, Inc. was selected to perform the automation design and to provide much of the necessary hardware and software. The owner retained responsibility for the following: 1. Design and installation of new control room on Operating Deck. 2. Specification, acquisition and installation of new switchboards and Motor Control Center (MCC). 3. Installation of all equipment. 4. Removal of old wiring, controls, monitoring and switchboards. 5. Replacement of engine room wiring. 6. Installation of control cabling, wiring, pneumatic and pressure tubing. 7. Replacement of steam turbine governor controls. 8. Specification, acquisition and installation of new communication system. 9. Specification, acquisition and installation of fire control system. 10. Design and installation of new primary steam piping to incorporate new throttle valves. 11. Design and installation of new ballast manifolds, utilizing remote controlled valves provided by G.R. Bowler. 12. Design and installation of new vacuum priming system for ballast and sea water systems in engine room. 13. Provide a replacement spare diesel powered generator to complement steam turbo generators. Design development and integration plan Siemens Moore Advanced Process Automation and Control System (APACS) hardware and Process Suite Graphical Interface Software were chosen for process control. G.R. Bowler specified the major condition sensing components, remote-actuated valves and sensing devices. This APACS hardware/software combination has been applied to other ships, ship control projects, including the ballast control and automation systems on the Edwin H. Gott and Edgar B. Speer 1, and for boiler automation on the LNG/C Matthew, SS Wright and SS Curtiss. However, the installation of the Callaway required integration into a vessel built in 1952 that was originally designed with a 3 man watch system. It was decided that the new Motor Control Center (MCC) equipment would be installed one deck higher, on the Main deck. This cleared the way for the new Control Room to be constructed on the Starboard side of the Operating deck. Electrical wire ways from the new switch gear were moved to permit separate control and monitoring cableways to be led. The Automation system installed in the engine room of the Callaway meets the requirements of NVIC 1-69 for a minimally controlled engine room. It also meets the requirements of USCG 46CFR, and ABS requirements for ACC (1 man watch) certification found in the ABS Rules for Building and Classing Steel Vessels

5 Major and minor systems addressed in this project 1. Boiler ACC 2. Boiler drum level, 2 element 3. Feed pump differential pressure 4. Fuel oil temperature 5. Atomizing steam 6. Burner management system 7. D.C. heater level 8. Propulsion turbine hot well level 9. Auxiliary exhaust pressure 10. Propulsion turbine and ship service turbo-generator gland seal 11. Propulsion turbine and ship service turbo-generator lube oil temperature. 12. Ballast system 13. Propulsion turbine throttle control 14. APACS system power supply 15. Propulsion turbine vibration monitoring 16. Fire detection and alarm system 17. Consoles and enclosures 18. Engineer watch call system 19. Plant pressure and temperature monitoring and control 20. Control room on Operating Deck 21. New Motor Control Center (MCC) and electrical switchboards 22. Updated steam turbo generator governor controls 23. New on-board communication system 24. Revised high pressure steam piping to incorporate new throttle valves 25. New vacuum priming system for ballast and sea water systems in engine room 26. New 315 KW auxiliary diesel generator 27. Revised control air system 28. Automated evaporator operation 29. New bilge water system with Oily Water Separator 30. Remote manual actuation for large engineroom sea valves System Descriptions All of the following systems control and computing functions are performed by Siemens / Moore, ABS Type Approved, Advanced Process Automation and Control System (APACS) hardware. The main systems Processors (Advanced Control Modules or ACMs) and the Operator workstation industrial PCs (HMIs) are redundant. Wherever there are redundant 5

6 pumps, motors or valves being controlled by the APACS, separate I/O modules have been assigned to eliminate the possibility of a single I/O module failure causing interruption of both the on-line and stand-by devices. All of the following operator actions can be performed on any one of the four HMI, 21 inch, industrial monitors: Manual / Auto selection Set Point adjustments Process Monitoring Loop output values Start / Stop Faceplate selection and operation Trend development Observation and alarm banner functions. Boiler Automatic Combustion Control (ACC) The Automatic Combustion Control system can be described as air lead oil, cross-limited, and inferential oil-control type. This design has proven to be the most stable, repeatable and flexible, and provides increased efficiency and fuel savings. The basis of the inferential system has been tested and used by all USN combat vessels for the last 30 years. The ACC systems interface with the Burner Management System (BMS) for low-fire and purge functions. Fuel oil valves and Forced Draft fan control devices are fail-safe. The fuel oil control valve is a force balanced, self-compensating Navy type valve with self contained low fuel oil pressure limiting. The forced draft fan airflow is controlled by a variable frequency drive motor control. The prior damper drives have been equipped with new input (I/P) converters to be used in the incidence of a drives failure. The Distributed Control System (DCS) architecture of the APACS system enables easy utilization of all process inputs to optimize the combustion process and for fast recovery of steam pressure to set point during maneuvering. Reaction of the controls is virtually simultaneous with the Captain s movement of the throttle lever while maneuvering. Boiler drum-level, 2 element Drum level systems utilize steam flow to characterize the feed water valve position and drum level to trim the results. In G. R. Bowler s experience, this system has been proven to be the most accurate and stable of all loop configurations for drum-level control. The feed water control valves fail open. There are two drum level transmitters per boiler, using separate taps. One transmitter provides level control and High/Low alarm functions. The other drum level transmitter provides separate, Low/Low boiler alarms and trips as well as High and High/High drum level for the main engine throttle alarms, cutback and trip functions. Interaction between the throttle control cut back function and the drum level control systems eliminates dangerous drum level swells and carryover. Feed pump differential pressure Feed pump pressure control for the ship s Coffin (steam) and the Byron Jackson (electric) feed water pumps are of a constant-differential design. Boiler drum and feed pump discharge pressures are compared and feed pressure is maintained at a set differential, higher than the 6

7 drum pressures. This system reduces wear on pumps and increases overall fuel savings. A new steam control valve was provided for the Coffin pump. A variable frequency drive is used for speed control of the electric feed pump. The failsafe points for both pumps are set to the slowest speed of the respective pumps. High & Low pressure alarms are provided. Auto start and stand-by functions insure constant feed water pressure if an online feed pump trip occurs. Fuel oil temperature control. F.O. temperature is measured and controlled. An APACS Proportional Integral Derivative (PID) loop and new control valve control steam to the Fuel Oil heaters. This loop is influenced by plant steam flow. The steam valve fails closed. High & Low temperature alarms are provided. Atomizing steam Atomizing Steam is measured and controlled by an APACS PID loop. A new control valve supplies steam to port and starboard burners. The steam valve fails closed. High & Low pressure alarms are provided. Burner management system The Burner management systems consist of independent APACS racks, Advanced Control Module (ACM) processor and I/O modules for each of the two boilers. New hardware includes burner and boiler fire-safe trip-valves with actuators and two Fireye, self-checking flame scanners per burner. The prior igniters have been retained. New solenoid junction boxes, housing the igniter transformers, are mounted away from the hot boiler fronts. Trip valve actuators are provided with local manual hand wheels. The igniters are provided with local push buttons for local-manual, supervised burner light off. All Alarms, Displays & Auto Shutdown functions are per ABS Table 7A, Instrumentation and safety system functions in centralized control station propulsion boiler and the USCG CFR 46, Oil-fired main boilers. Automatic burner sequencing strategies are utilized to minimize the frequency of burner light off and shut downs to minimize smoke. D.C. heater DC heater control is of conventional design. New make-up valves direct make-up condensate to the condenser to increase water level and a new spill valve diverts condensate to the feed tanks to decrease level in the D.C. heater. The two PID loops are part of the APACS system. Two DC heater level transmitters were provided, one for control and the other for High & Low level alarm functions. Propulsion turbine hot well level Main Propulsion Turbine hot well level is controlled by a new control valve, re-circulating condensate back to the condenser. This valve fails closed. A new stainless steel float type level transmitter is used for hot well level sensing. One PID loop is part of the APACS system. High & Low level alarms are provided. Auxiliary exhaust pressure Auxiliary exhaust pressure is controlled by 3 PID loops in the APACS system. New 3 I/P extraction and auxiliary exhaust dump valves were utilized. A new 2 make-up valve replaced 7

8 the existing Leslie valve. The valves were found to be obsolete, in need of repair and undersized. All three valves fail closed. High & Low pressure alarms are provided. Propulsion turbine and ship service turbo-generator (SSTG) gland seal New gland seal regulating valves control the Propulsion Turbine and SSTG gland seal pressure. The main engine incorporates one valve to make-up gland seal pressure. The SSTGs have one valve for make-up steam to the gland seals and one valve for dumping off excess gland seal steam. The Propulsion Turbine gland seal system has one PID loop in APACS. The SSTG gland seal systems have two PID loops per SSTG in APACS. Valves fail closed. High & Low pressure alarms were provided. Propulsion turbine and ship service turbo-generator lube oil temperature Propulsion turbine and ship service turbo-generator lube oil temperature is controlled by a new control valve in the outlet of the waterside of the coolers. The PID loops are part of the APACS system. Valves fail open. High & Low temperature alarms are provided. Ballast system New pipe ballast manifolds were designed and constructed that replaced aging trunk type manifolds in the lower engine room. Automatic valves replaced the manual ballast valves. The new ballast system includes 18 ballast tank manifold valves. Each tank valve has an air-operated actuator, with modulating 4-20 ma inputs for operator positioning of valves and 4-20 ma position feedback to display actual valve position. Auxiliary and main pump suction, crossover, and overboard system butterfly valves are fitted with air-to-open, solenoid- New Starboard side ballast manifold operated actuators with limit switch feedback. The existing ballast sea valve was left in place and automated by adapting a motorized actuator with modulating 4-20 ma input and position feedback. Ballast functions are managed by the APACS system. The level of each tank is compared with either a pre-selected Ballast Plan or an individually selected set point. The APACS logic automatically stages the necessary pumps and valves to allow either filling (pump in) or emptying (pump out) of the selected tank(s). All functions are sequenced automatically and accessed readily from the HMI graphics screens. Ballast overboard valves fail closed. Ballast tank level transmitters provide level monitoring and Alarm functions. Valve position feedback provides alarm functions for any valve position vs. demand error. All ballast valves are ABS Type approved Bray Valve and Control USA, Inc. Series 30/31 valves. Final tank stripping when pumping out is managed remotely by the watch standing Engineer at the control room console. 8

9 Propulsion turbine throttle control Automatic propulsion turbine throttle control is from one of four throttle control stations. The throttle control stations are located at the main engine room control console, bridge center, and the Port and Starboard bridge wings. Each control station is equipped with a Prime Mover Controls (PMC) throttle control head and integral, engine-order telegraph. Each station also has the required, USCG/ABS alarm and control function lights and switches (as per ABS Part 4, Chapter 9, Section 4, Table 4). Each of the throttle control stations incorporates redundant RPM, fault monitored, demand signal 4-20 ma transmitters. Redundant APACS processors perform the throttle control system logic. All Alarms, Displays, Auto Start and Auto Shut Down functions are per ABS Table.2, Instrumentation and controllers in centralized control stations all propulsion and auxiliary machinery and Table 4, Instrumentation and safety system functions in High pressure turbine throttle valves centralized control station propulsi on steam turbines. Ahead and astern, turbine throttle control are each performed by a pair of valves for each turbine. One 6 and one 2, 600 # steam-control valve are piped in parallel and provide precise turndown for accurate speed control of each turbine. The ahead and astern throttle piping also incorporates an automated ahead trip valve for ahead trip in the HP turbine piping and one astern guardian valve in the astern turbine piping. Redundant, propeller shaft- RPM transmitters are constantly compared and alarmed if an error occurs. Both the High Pressure and Low Pressure turbines are equipped with independent, rotor-rpm transmitters to be used for speed governing and over-speed trip functions. The trip valves are also actuated by failure of the lubricating oil system and low main condenser vacuum. Remote manual operation of the throttle valves can be performed by control knob inputs at two independent ABS, Type-approved, Siemens/Moore, model 353 control stations, powered and connected independently of the APACS, main throttle control system. The two remote manual operating stations are mounted in the engine room control console. One of the remote manual 353-control stations is dedicated for ahead throttle-valve control and the other is dedicated for astern throttle-valve control. Local manual control of the throttle valves can be performed by the attached hand-wheels that are provided on each of the 6 throttle control valves. Low main steam pressure & high boiler drum level throttle run-back functions are provided with emergency override protection. APACS system power supply All APACS system power requirements are supplied by redundant, load sharing, battery backed, 24VDC units. Four rack-mounted, marine industrial UPS units supply power for two 9

10 HMI, industrial PCs and four, 21 SVGA monitors. AC power feeding the 24 VDC systems and the Universal Power Supplies come from two feeders; one from the main switchboard and one from the emergency switchboard. This configuration is per ABS 4-9-3/3.5.1 System power supply. Propulsion turbine vibration monitoring Vibration monitoring is performed by the APACS system. Indikon vibration and speed devices were used. All inputs provide alarms at warning and danger set point levels. A. Vibration transmitters, proximity probes for HP and LP turbine shaft in X and Y planes forward and aft. - (8) locations. B. Position transmitters, proximity probes for HP and LP turbine shaft thrust in (2) locations. C. Speed transmitter probes for HP and LP turbine to measure turbine speed in (2) locations. D. Vibration transmitter and accelerometer for vibration measurement of reduction gears in (2) locations. Fire detection and alarm system An independent USCG approved, Hiller Systems, Inc. fire detection and alarm system was installed. Alarm panels are mounted on the bridge and in the engine control room. The system consists of thirty three (33) fire and smoke detectors mounted throughout the engineroom spaces including the Port and Starboard unloading diesel generator rooms, bow thruster compartment, and emergency generator room. Consoles and enclosures The engine-room console houses four ABS type-approved, 21-inch, SVGA, rackmounted industrial monitors, two ABS typeapproved industrial PCs, four rack- mounted UPS units and one PMC, throttle control-head panel. The engine-room APACS enclosure is a front and back door enclosure, housing five APACS racks, twenty-seven, I/O marshaled, termination panels and a Fireye amplifier rack. Bridge center and wing consoles are mounted in place of the existing Engine Order Telegraph pedestals. All engine-room motor APACS enclosure start/stop functions and all control loop set points as well as manual/auto control interfaces are via HMI, graphical faceplates, similar in appearance to single loop controllers, with mechanical pushbuttons and switches. Engineer watch call system The Engineers call system incorporates existing cabin alarm panels with new interface wiring to the APACS system I/O. An HMI graphic was provided for call out of engineers from the engine room control console. 10

11 Plant pressure and temperature monitoring and control The automation system receives vital and non-vital pressures and temperatures and sends operating commands via the following numbers of inputs and outputs: Number used RTDs 71 Transmitters with 4-20 ma signal 118 Other transmitters, including RPM, vibration, Oxygen, etc. 25 Throttle demand senders 8 Valve position feedbacks 35 VFD Speed signals 5 Relay outputs 139 Discreet inputs 173 Discreet outputs (not relay) 3 All pressure and temperature inputs have high and/or low alarm set points. The APACS I/O Data Sheets show names of processes being monitored. Control room on Operating deck The Starboard side Operating Deck was chosen for installation of the new Control Room. This required that the new MCC panels be installed on deck directly above, called the Main Deck on the Callaway. Equipment installed within the Control Room includes the new main switch board, the Control Console with throttle and four (4) HMI 21 monitors, Ship Service and Unloading Generator panels, APACS cabinet, Event printers, HVAC system, fire alarm panel, and shore power panel. The room is fitted with two doors, three windows, a lowered acoustical New control room in background overhead, and all structure is insulated with 2 fiberglass insulation. The main propulsion turbines are visible above the control console, and the boiler fronts are visible through the window in the forward bulkhead. A desk and book shelf are also fitted. New motor control center and electrical switch boards As required for ACC minimally manned spaces, the new switchboards were located inside of the new control room. The switch board located on the inboard bulkhead of the new control room, facing outboard includes the following: 1. Circuit breakers for the two (2) 400 KW SSTGs 11

12 2. SSTG controls and metering, including new Woodward 2301a electronic governor controls. 3. Circuit breaker for new 315 KW standby diesel 3406 Caterpillar generator. 4. Standby generator controls and metering, including 2301a Woodward electronic governor controls that feature automatic start and circuit breaker closing upon blackout Volt 3 phase distribution. 6. Steering gear alarms and feeders. The 120 Volt switch board is a separate unit, located in the control room opposite the main switch board, facing inboard. This permitted space on the inboard bulkhead for the main control room console. The Motor Control Center (MCC) was located on the Main deck, the next deck above the control room. The new MCC is larger than the original unit, which permitted pull-out, draw type construction (buckets). The MCC is divided into three (3) sections with three (3) feeds. Magnetek variable frequency drives were installed in the MCC for the following motor controllers: Two (2) forced draft fans One (1) Byron Jackson Feed pump Two (2) main condensate pumps Two (2) Fuel Oil service pumps The switchboard and MCC renewal was considered an in kind r eplacement, and a load analysis and short circuit analysi s were not required. The new switch board and MCC components are rated for 65,000 amps interrupting capacity, with the buss is braced for 42,000 amps interrupting capacity. M & I Electric Industries supplied the main switch board and MCC equipment. The relocation of the switchboards and MCC made it necessary to rewire all the engine room equipment. The existing cable trays were used where possible, but most trays were removed and new trays were built to accommodate the new locations of the switch board and MCC. Motor Control Center Updated steam turbo generator governor controls Pneumatic actuators controlled by a 2301a Woodward electronic governor were installed in place of the original General Electric mechanical/hydraulic controls. New on-board communication system A new Hose- McCann sound powered telephone system was installed. This replaced an original system that was not capable of handling the additional communication requirements dictated by the ACC certification. In all, twelve (12) new phone sets were installed throughout the vessel, including installations in three (3) Engineer rooms that were not originally fitted 12

13 with phones. Also, three additional sets of flashing beacons were installed in the engine room, bringing the total of these beacons to six (6) sets. Revised high pressure steam piping to incorporate new throttle valves The prior steam throttle valves assembly and control console were removed and replaced with the valve system described above. See Figure 1 for Callaway Class Main Throttle Valve Train Piping. The new piping was laid out to follow the original piping geometry where practical, while providing adequate access to all components, particularly the manual override devices. The new piping was able to be supported by many of the original support elements. An additional variable spring hanger assembly was added to support the ahead main trip valve and the astern guardian valve. Each of these valves with associated actuators weighs approximately 2500 pounds. One hundred percent radiography of the finished welds was accomplished, as well as hydrostatic testing of the completed piping assemblies. High pressure steam piping design, fabrication and inspection was performed per 46 CFR 56; per part of the ABS Rules for Building and Classing Steel Vessels 2000; and also per the ASME Code for Pressure Piping, Power Piping, ASME-B31.1. Figure 1, Modifications to high pressure steam piping New vacuum priming system for ballast and sea water pumps A new vacuum pump priming system was installed, provided by Sterling Fluid Systems. It consists of two (2) large capacity vacuum pumps ( vacuum). The pumps are mounted on top of a water reservoir tank fitted with two (2) heat exchangers to prevent over heating. The vacuum tank connects through 1 ½ NPT piping to three (3) zones as follows: 1. Port ballast system 2. Starboard ballast system 13

14 3. Two (2) engine room fire pumps, cooling water pump and bilge pump New 315 KW auxiliary diesel generator A Caterpillar 3406, 315 KW diesel generator was installed on the Main deck, just outboard of the new MCC. Designed strictly for auxiliary operation, the unit is an auto start, radiator cooled, 1800 RPM engine that drives a 60 HZ 480 Volt, 3 Phase generator. Standby black-out logic directs its operation. Revised control air system Since most of the automated valves are air actuated, some modifications were made to the vessel s air system to ensure adequate air supply to all points of use. A second refrigerated air dryer was installed in parallel with the existing unit. Coalescing pre and after filters were installed for the dryers. The existing 1 pipe air header was extended down to the engine room Operating deck and inboard to the area of the throttle isolation and control valves. From this main header, two sub headers of ¾ stainless steel tubing were run. One sub header forms a complete loop around the main engine opening along the overhead beams of the Operating Deck. The other sub header forms a u around the reserve feed water tank on the lower engine room level. Smaller stainless steel tubing runs to each point of use from the headers as needed. To prevent sudden drops in overall system pressure, two point-of-use air receivers were installed. The larger of these has a 120 gallon capacity, and supplies stored air for the throttle isolation and control valves. A smaller 60 gallon air receiver provides the air supply for the ballast control valves. Automated evaporator operation Three APACS PID control loops control the operation of the evaporator. Loop 1 controls the water level in the evaporator. New SS float type level transmitter and new water supply control valves were provided for this loop. Loop 2 controls the vapor output of the evaporator by controlling the steam input pressure. Loop two s process input is the distilled water tank level. As the level in the tank drops below set point the steam valve will increase steam pressure to the evaporator. New tank level transmitters and steam control valve was provided. Loop 3 is a high evaporator steam supply pressure cutback loop. This loop keeps the steam pressure below the design maximum pressure. For increased efficiency the vapor line from the evaporator was connected to the LP extraction inlet on the 1st stage heater. This arrangement will cause the evaporator to run under the same 15 vacuum as the 1 st stage heater and generates vapor at approximately 175 degrees F. Previously the vapor line was connected to the 15 PSI auxiliary exhaust system which required heating to 250 degrees F. to generate vapor. New bilge water system with Oily Water Separator The bilge suction piping forward and aft of the stern thruster tunnel was redesigned and replaced which included new motorized butterfly suction valves with in-line check valves. A new suction strainer and vacuum float were installed on the bilge pump. The control of the bilge pump and valves can be performed locally or remotely from engineroom console per ACC requirements. Three (3) high/low float switches for bilge level monitoring were mounted in the engineroom bilges. A new oily water separator with oily content meter was installed in Port shaft alley with suction forward and aft of the stern thruster tunnel. 14

15 Remote manual actuation for large engineroom sea valves Installed reach rod controls to both port and starboard high and low sea suction valves. All four valves can be actuated from the operating deck just outside the aft control door. All other large sea valves in the lower engineroom have been automated. Unique features of automation controls on Callaway HMI Graphics and Operator Interface The four 21 ABS Type approved, SVGA monitors, the Human Machine Interface (HMI) provides all of the necessary control selection and manipulation capabilities required for engine room operation. The thirty plus individual graphics screens were designed and crafted to provide an intuitive presentation of engine room control and monitoring points for the operator. Active on-screen alarm banners and graphics selection buttons provide quick and easy access to a wealth of information. The operator (engineer-on-watch) can rapidly gather an accurate and timely overview of the critical and non-critical systems. This enables not only timely but correct interpretations of conditions and trends and allows for calculated and effective responses. Trending and Historical Data A vital component of the HMI is the ability to call up vital information. A historian program stores every analog input signal, controlled process variable, set point and control output, once per second to a dedicated Hard Disk. This data can be retrieved and trended on screen to show actual values during known operating conditions. This data can also be compiled into specialized reports as desired. Historical log of propeller rpm demands, response and Steam valve opening data 15

16 Record of alarms The main plant operating screens all list the details and status of the last five (5) system alarms. A separate screen details all alarms since last re-set. An event printer keeps a running print-out of all alarms. Motor and Pump Backup Systems Rather than waiting for an alarm or failure, the system automatically monitors the status of certain pumps and motors and starts a designated standby unit when Screen listing alarm data required. Some of the systems covered include: Main Condensate Pumps, Main Circulating Pumps, Control and Ship s Service Air Compressors, Fuel Oil Service pumps, Main Engine Lube Oil Pumps (this is a unique system comprised of one electric driven pump and one steam driven pump), Vacuum Priming pumps, Sanitary (Potable Water) pumps and Main Feed water pumps. Automatically Sequenced Soot Blowing Existing, manual-interface, control switching was paralleled with APACS, DCS I/O connections. Each soot blower motor is commanded and monitored by the APACS logic. Sequencing is performed by IEEE recognized, Sequential Function Chart logic. The program controls the proper timing and warm-up periods necessary for effective soot blowing. Automatic Plant Restart Restarting an entire plant following a total shutdown, whether planned or unplanned is quite an undertaking. The Callaway has been provided with the sequencing logic and controls to allow One Button Plant Restart. All critical pumps, forced-draft fans, boiler purging and related functions are started sequentially, via a single button, saving a tremendous amount of time and providing a level of confidence unavailable otherwise 16

17 Preventive Maintenance Planning All controlled motors and pumps are monitored for operating status. The run times are totalized to enable balanced operating schedules as well as coordination of preventive maintenance. Effectiveness review I. Fuel efficiency The owner forecast a reduction in fuel consumption of 5% due to improved process control and efficiency improvements plus a fuel consumption reduction of 5% due to replacement of seals and certain of rows of blades in the main propulsion turbines. Actual experience measured in the spring of 2002 is 17.1% total reduction in fuel consumption at 16 nozzles, with vessel at full speed, loaded on Lake Superior. With the rehabilitation of the turbine rotors, the plant is now operated at 16 nozzles, achieving a nominal speed of 15.6 mph. Prior to the project, the vessel was normally operated with 17 nozzles open, at a nominal speed while loaded of 15.1 mph. Due to clean combustion, smoke and soot accumulation were dramatically reduced. Stbd. Bridge wing throttle II. Manning This project permitted the issuance of a new Certificate of Inspection that reduced engine room manning by 3 positions. The first year of operation demonstrated the success of this, with no additional engine room over-time and a reduction in equipment breakdowns. Comparison of Engine department manning Rating No. before No. after Licensed Chief Engine er 1 1 First Assistant Engineer 1 1 Second Assistant Engineer 1 1 Third Assistant Engineer 2 2 Unlicensed Oilers 3 Wiper-gateman 1 1 Handyman* 1 1 Total complement 10 7 *This one handyman, befo re and after the project completion, is assigned full time to unloading and deck equipment, outside of the engine room spaces. 17

18 II. Ballasting control The new automated system has demonstrated the ability to reduce approximately 1 hour from the required ballasting time for the ship. This has enabled improved turn around times at loading docks where loading rate is sufficient to take advantage of this improved ballast handling time; normally only when loading taconite. Basic control screens of automation system a n e u v e r i n g M i n f o r m a M Maneuvering information screen 18

19 Condensate system screen Boiler overview screen 19

20 Steam system screen Ballasting control screen 20

21 Ballast plan commands and pump status Boiler status screen 21

22 22