PLANT BOWEN UNIT 3 FLUE GAS DESULFURIZATION … · DCS when the FGD Absorber Bypass Damper is not...

BWN-3-02603.401 Rev 0 Process Description Plant Bowen

Date Printed 2/22/2011 of 21

/s/ Gary Smith Approved Plant Review Board /s/ Tim Crump Approved Operations Manager /s/ Tim Banks Approved Plant Manager Date: 07-12-2010

PLANT BOWEN UNIT 3 FLUE GAS DESULFURIZATION SYSTEM

JBR MIXER SYSTEM PROCESS DESCRIPTION Document No. 2603.401

NOTE: If you are working with a printed copy of this document, it is NOT a Controlled Copy.

Please be sure to check online for the most recent revision.

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Confidential Information of 21

T able of C ontents

2603.401 PROCESS DESCRIPTION 3

2603.401.1 Safety Considerations 3 2603.401.2 Process Flow Description 4 2603.401.3 Process Description 5

2603.401.3.1 Introduction 5

2603.401.3.2 System Components 7

2603.401.3.2.1 JBR Mixer Drive Motor 8

2603.401.3.2.2 JBR Mixer Gear Reducer 9

2603.401.3.2.3 JBR Mixer External Lube Oil 11

2603.401.3.2.4 JBR Mixer Upper And Lower Shaft With Impeller 13

2603.401.3.3 Summarized Controls Description 15 2603.401.3.4 Detailed Controls Description 16

2603.401.4 Process Flow Description 18 2603.401.5 Drawing References 19

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2603.401 P R OC E S S DE S C R IP TION 2603.401.1 S afety C ons iderations

1. All Operating Companies Safety and Health Manuals shall be followed at all times.

2. The Southern Company Generation Clearance Procedure shall be followed at all times.

3. A thorough Job Safety Briefing (JSB) shall be completed before beginning work.

4. Employees should always use the proper Personal Protection Equipment (PPE) for the task they are performing.

5. Personnel must observe standard safety precautions when working around or with high temperature piping systems.

6. Personnel must be aware that components of this system are maintained in an automatic mode of operation. The equipment may start at any time without warning.

7. Personnel should remain clear of all rotating machinery, whether operating or in standby, at all times during unit operation.

8. Rotating machinery must never be placed in service without the appropriate equipment guards in place.

9. No attempt should be made to bypass or eliminate equipment safety interlocks. Doing so could result in equipment damage and possible injury to plant personnel.

10. Follow proper Confined Space Entry Procedures when entering confined spaces.

11. When employees are performing work on or associated with exposed lines or equipment energized at 50 volts or more, persons trained in First Aid including Cardiopulmonary Resuscitation (CPR), shall be available within 4 minutes per OSHA 1910.269 requirements.

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2603.401.2 P roc es s F low Des cription The following subsections contain function and description of major components within this system. This procedure contains summarized and detailed controls descriptions of this system. This procedure contains a step by step process flow description of this system.

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2603.401.3 P roc es s Des c ription 2603.401.3.1 Introduc tion

The JBR Mixer System works in conjunction with oxidation air and the sparging effect created by the incoming flue gas to ensure adequate mixing of JBR slurry to refresh the reactants in the jet bubbling zone. Continuous operation of the mixers are required to maintain JBR SO2 removal efficiency. The JBR Mixer System also serves to maintain slurry solids in suspension to prevent deposition in the bottom of the JBR vessel. The JBR Mixer System consists of four low speed mixers (1 - 4) mounted on the roof of the JBR Vessel. Mixers 2 & 4 rotate in a clockwise direction and mixers 1 & 3 rotate in a counter clockwise direction to promote good mixing and suspension in the JBR Vessel. The shaft of each mixer extends through the JBR Vessel top and into the JBR slurry reaction zone below the gas sparger tubes 60 inches above the vessel floor. Each mixer consist of a drive motor, gear reducer, external lube oil system, and upper and lower shaft assembly with three blade mixer impeller and instrumentation for lube oil flow and temperature.

NOTE: The JBR can effectively be operated with only three of the four mixers running, unless the failed mixer is the #2. Mixer #2 is in alignment with the suction of the Gas Cooling Pumps, running with this mixer inoperable allows the gypsum to settle out and form a mound which can block the suction of the Gas Cooling Pumps. Any operation with less than four mixers available should be with the concurrence and direction of the System Engineer and the System Owner.

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Each mixer has a connection to the Make-Up Water System for Shaft Sealing Water and Lube Oil Cooling. The Make-Up Water System maintains a continuous supply of water to each mixer through manual valves and is monitored by a low flow switch.

Mixer #2

Mixer #1

Mixer #3

Mixer #4

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2603.401.3.2 S ys tem C omponents

The JBR Mixer System consists of four low speed mixers (SK-MX-5001, 5002, 5003, and 5004) mounted on the roof of the JBR Vessel. The mixers are Model 783QS125 manufactured by Lightnin. Each mixer consists of a drive motor, gear reducer, external lube oil system, and upper and lower shaft assembly with three blade mixer impeller and instrumentation for lube oil flow and temperature.

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2603.401.3.2.1 J B R Mixer Drive Motor

Number Sheet Rev Title P&IDs

• D3M20009 1 3 P&ID – Jet Bubbling Reactor JBR Piping Vendor O&M Manuals

• S90838 1 0 Scrubber-FGD-Bearing Installation & Maintenance Guide

• S90775 1 0 Scrubber - FGD - JRB Absorber Agitators - Installation, Operation, 5081 772-0000 & Maintenance Manual

• S82438 1 0 Scrubber-FGD- Agitator-JBR Absorber Agitators-Mixer Installation, Operation & Maintenance Manual

F unc tion

The JBR Mixer drive motors for each JBR mixer provide the motive force to the mixer assembly. The force generated by the motor is coupled through a gear reducer which lowers the mixer operating speed while raising the mixer torque. The combination of low speed and high torque is necessary for the efficient mixing of a viscous fluid such as the gypsum slurry in the JBR.

Des c ription

Each JBR Mixer is driven by a Siemens 460V, 125 hp, 3 phase, FR 445TS motor operating at 1200 rpm with installed 240V strip space heaters. The horizontally mounted motor is coupled to the Mixer Gear Reducer through a fluid coupling. The motor is mounted on a common raised foundation with the Mixer Gear Reducer.

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2603.401.3.2.2 J B R Mixer G ear R educ er






F unc tion

The JBR Mixer Gear Reducer converts the horizontal high speed 1200 RPM output of the motor, to a vertical low speed high torque shaft output of 17 RPM. The low speed, high torque output of the mixer is required to facilitate efficient mixing due to the high viscosity of the gypsum slurry.

Des c ription

The Gear Reducer for each JBR Mixer is a Hansen Transmission Model P4 triple reduction, bevel gear type reduction gear with a 71.2:1 reduction ratio. Cooling and lubrication of the high speed section of the gear reducer is accomplished by oil slinger lubrication. The low speed section of the gear reducer utilizes splash oil lubrication with the exception of the low speed shaft upper and lower bearings which are grease lubricated. Lubrication of both the high and low speed sections is supplemented by the location of the oil returns from the external lube oil system. An attached external lube oil system provides for filtration and cooling of the gear reducer lube oil. Verification of oil level in the reducer is by dipstick. Design of the gear reducer allows for simple in place splitting of the high speed cover from the bevel gear section for maintenance of high speed components. Inspection covers allow for visual inspection of internal components. The input shaft of the gear reducer is connected to the drive motor through a fluid coupling. The output shaft of the gear reducer is coupled to the upper mixer shaft assembly using a removable coupling. Counter clockwise mixer rotation for JBR Mixers 1 & 3 is accomplished by fixed reverse rotation in the gear reducers for those mixers. The gear reducer is mounted on a common raised foundation with the Mixer Motor and provides for access to the upper mixer shaft coupling and vapor seal.

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2603.401.3.2.2 J B R Mixer G ear R educ er

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2603.401.3.2.3 J B R Mixer E xternal L ube Oil






• S82591 1 0 Scrubber FGD - JBR Absorber Agitators - Assembly Drawing - External Lube System

F unc tion

Each JBR Mixer is equipped with an External Lube Oil system mounted on the low speed housing of the gear reducer. This system provides for filtration, cooling, and monitoring of gear reducer lube oil temperature and pressure.

Des c ription

Each system consists of a lube oil pump with 460V AC, 1 hp, drive motor, pump relief valve, simplex oil filter, oil cooler, isolation valve, and instrumentation for lube oil temperature and flow. The external lube oil system withdraws lube oil from the gear reducer low speed housing drain and returns cooled filtered lube oil to the high speed cover and low speed housing oil ports. A temperature gage and temperature switch monitor temperature of the lube oil removed from the gear reducer prior to the oil cooler. The temperature switch provides alarm indication of high lube oil temperature at the DCS. A flow switch monitors lube oil supply flow to the gear reducer at the cooler outlet and provides alarm indication of low lube oil flow at the DCS and tripping of the affected JBR Mixer to protect it from damage. A flow switch in the Make-Up Water System monitors water flow to the JBR Mixer which is used as the cooling medium in the lube oil cooler and for mixer shaft seal water. The flow switch, when activated, will only provide alarm indication of low water flow at the DCS when the FGD Absorber Bypass Damper is not in the bypass position. Refer to Drawing R280947-K, (S85291 A), JBR Absorber Agitators Assembly Drawing External Lube System.

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2603.401.3.2.3 J B R Mixer E xternal L ube Oil

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2603.401.3.2.4 J B R Mixer Upper and L ower S haft with Impeller






F unc tion

The JBR Mixer Upper Shaft and Lower Shafts transmit the torque from the output shaft of the gear reducer to the mixer Impeller located in the JBR slurry reaction zone. The mixer impeller maintains the continuity of slurry within the JBR vessel by preventing the sedimentation of gypsum solids. Additionally, the mixer assembly promotes efficient SO2 removal by maximizing flue gas contact with the limestone/gypsum slurry in suspension.

Des c ription

Both the Upper and Lower Shafts are constructed of 16” Schedule XS pipe with a 3/16” natural rubber coating starting from just below the vapor seal contact area. The 33’10” Upper Shaft is connected to the gear reducer output shaft removable coupling at its top flange. The Upper Shaft penetrates the top of the JBR Vessel through a Vapor Seal which is supplemented by seal water from the Make-Up Water System to prevent the escape of flue gas from the JBR Vessel. The Upper Shaft lower flange connects to the upper flange of the 18”6” Lower Shaft. The Lower Shaft extends into the JBR Vessel where the impeller hub is keyed and bolted to the bottom of the Lower Shaft. Each of the three fixed position blades with integral stabilizer fins is bolted to the impeller hub providing for a 20’ impeller diameter. The steel impeller blades and hub are covered with 3/16” natural rubber coating with an additional 3/16” of coating on the blades leading edge.

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2603.401.3.2.4 J B R Mixer Upper and L ower S haft with Impeller

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2603.401.3.3 S ummarized C ontrols Des c ription

The controls for the JBR Mixers ensures that the mixers perform their primary function, as listed in the Introduction of this document. There are four JBR Mixers, each having a dedicated lube oil system. The Makeup Water System supplies seal water to the JBR Mixers as well as, cooling water to each of the mixer’s lube oil system. The logic narrative that follows addresses one JBR Mixer, however since each mixer is identical in design, the narrative can be applied to all four JBR Mixers. The permissives to start any JBR Mixer are as follows:

• JBR Wide Range Level above the Low-Low setpoint (118”).

• JBR Mixer not in tagout.

• JBR Mixer Lube Oil Flow Normal.

The JBR Mixers are interlocked and will trip due to the following:

• JBR Wide Range Level below Low-Low-Low 106”.

• JBR Mixer Lube Oil Flow Low (120VAC contacts).

The alarms generated by the JBR Mixers logic are as follows:

• JBR Mixer Seal Water Low Flow (<0.5 gpm decreasing). • JBR Mixer Motor Current Abnormal (120VAC contacts). • JBR Mixer Failed Start. • JBR Mixer Lube Oil Temperature High 175oF. • JBR Mixer Lube Oil Flow Low (120VAC contacts). • JBR Mixer Lube Oil Pump Failed Start. • JBR Mixer Not Running.

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2603.401.3.4 Detailed C ontrols Des c ription

The controls for the JBR Mixers ensures that the mixers perform their primary function as listed in the Introduction of this document. There are four JBR Mixers each having a dedicated lube oil system. The Makeup Water System supplies seal water to the JBR Mixers as well as, cooling water to each of the mixer’s lube oil system. The logic narrative that follows addresses one JBR Mixer, however since each mixer is identical in design, the narrative can be applied to all four JBR Mixers. The JBR Mixers logic requires that the JBR Wide Range Level be above the low-low (118”) level alarm setpoint to start any mixer. The mixer to be started must also not be in tagout and the lube oil flow to that mixer must be within the normal and expected range. If any of these conditions are not met before startup, the mixer will not start. The JBR Mixers are interlocked by JBR Wide Range Level, such that if the JBR level fall below the low-low-low 106” level setpoint, the mixers will trip. The mixers are also interlocked by lube oil flow to the mixer gearbox; if the flow drops outside of the normal flow range during mixer operation, the mixer will trip. The alarms generated by the JBR Mixers logic are as follows:

• JBR Mixer Seal Water Low Flow • JBR Mixer Motor Current Abnormal • JBR Mixer Failed Start • JBR Mixer Lube Oil Temperature High • JBR Mixer Lube Oil Flow Low • JBR Mixer Lube Oil Pump Failed Start • JBR Mixer Not Running

Low seal water supply to the mixer is only an alarm. This alarm will only be actuated when the FGD Bypass Damper is not in the FGD bypass position and a seal water low flow condition exists (<0.5 gpm decreasing).

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2603.401.3.4 Detailed C ontrols Des c ription

The JBR Mixer Motor Current Not Normal alarm is actuated by a 120VAC contact from the motor control circuits. This condition must be active for five seconds continuously to generate this alarm. This alarm is not latched and will clear when the condition clears. This alarm is used only for annuciation and is not used for active protective function. The JBR Mixer Failed Start alarm will become active two seconds after an attempt to start the mixer motor, if the motor that is running feedback is false. Each JBR Mixer’s lube oil system incorporates a local temperature and flow switch. The temperature switch is located in the return path of the lube oil flow from the mixer gear low speed housing. Should the temperature exceed that of the setpoint 175oF for the local temperature switch, a dry contact is closed and generates an input into the DCS for alarm purposes only. The flow switch for the lube oil system contains a dry contact that will be closed when lube oil flow is within the normal range. This contact will open and provide an input to the DCS that will generate a JBR Mixer Lube Oil Low Flow alarm only when it’s associated mixer is running and will trip it’s associated mixer. The JBR Mixer Lube Oil Pump Failed alarm will become active two seconds after an attempt to start the lube oil pump motor, if the motor that is running feedback is false. When the Wide Range JBR Level is above the low-low (118”) setpoint and the JBR Mixer Running feedback is false, a JBR Mixer Not Running alarm will be generated for each JBR Mixer that is not running.

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2603.401.4 P roc es s F low Des cription S haft S eal and L ube Oil C ooling Water Process Flow

S tep 1.

The JBR Mixer receives water from the Make-Up Water System for Shaft Sealing and Lube Oil Cooling. Make-Up Water passes through a flow switch inlet valve (WF-109, WF-110, WF-111, and WF-112), a flow switch (WF-FISL-5161, 5162, 5163 and 5164), a flow switch outlet valve (WF-132, WF-133, WF-130, and WF-131), and a flow throttle valve (WF-113, WF-114, WF-115, and WF-116) before entering the JBR Mixer where flow splits for sealing and cooling. Refer to Drawing No. D3M20009, Sheet 1, Rev 3, Jet Bubbling Reactor JBR Piping.

External Lube Oil System

S tep 2.

The external lube oil system withdraws lube oil from the JBR Mixer gear reducer low speed housing drain. Lube oil then flows through the lube oil isolation valve and enters the lube oil pump where lube oil pressure is increased and then discharged. Refer to Drawing No. R280947-K (S85291 A), Sheet 1, Rev A, JBR Absorber Agitators Assembly Drawing External Lube System. S tep 3.

The lube oil leaving the lube oil pump passes through lube oil temperature switch (SK-TSH-5015, 5016, 5017, and 5018) and is filtered as it passes through the lube oil filter. Lube oil then passes the lube oil temperature gauge before entering the lube oil cooler. Refer to Drawing No. R280947-K (S85291 A), Sheet 1, Rev A, JBR Absorber Agitators Assembly Drawing External Lube System.

S tep 4.

The lube oil then enters the lube oil cooler where sufficient heat is removed from the lube oil and transferred to cooling water. After the lube oil exits the lube oil cooler, it passes through the lube oil flow switch (SK-FSL-5015, 5016, 5017, and 5018) before entering the lube oil supply header, where lube oil is delivered to the gear reducer high speed cover and low speed housing oil ports. Refer to Drawing No. R280947-K (S85291 A), Sheet 1, Rev A, JBR Absorber Agitators Assembly Drawing External Lube System.

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2603.401.5 Drawing R eferenc es

The JBR Mixer System is illustrated on the following drawings:


• D3M20009 1 3 P&ID – Jet Bubbling Reactor JBR Piping

Elementary Diagrams • E3E30220 1 2 Elementary Diagram JBR Tank Mixer 1, 2, 3, & 4

• E3E30220 2 2 Elementary Diagram JBR Tank Mixer 1, 2, 3, & 4

• E3E30274 1 0 Elementary Diagram JBR Mixer 1, 2, 3, & 4 Lube Oil System Pump

• E3E30274 2 0 Elementary Diagram JBR Mixer 1, 2, 3, & 4 Lube Oil System Pump

Wiring Diagrams • E3E30356 2 0 Wiring Diagram JBR 3/4 480V MCC A Frames 3 & 4

• E3E30356 5 0 Wiring Diagram JBR 3/4 480V MCC A Frames 9 & 10

• E3E30359 1 0 Wiring Diagram JBR 3/4 480V MCC AC Frames 1 & 2

• E3E30359 4 0 Wiring Diagram JBR 3/4 480V MCC AC Frames 7 & 8

• E3E30360 3 0 Wiring Diagram JBR 3/4 480V MCC B Frames 5 & 6

• E3E30360 5 0 Wiring Diagram JBR 3/4 480V MCC B Frames 9 & 10

Distribution Panels

• E3E30128 1 5 Distribution Panel JBR 3/4 Electrical Bldg 120/208V AC Panel A

• E3E30129 1 3 Distribution Panel JBR 3/4 Electrical Bldg 120/208V AC Panel B

DCS I/O Diagrams

• E3E30440 2 0 Wiring Diagram Limestone Elect Bldg DCS I/O Cabinet 5141 Base 0

• E3E30410 2 1 Wiring Diagram JBR Elect Bldg DCS I/O Cabinet 3101 Base 0



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Number Sheet Rev Title DCS I/O Diagrams





• E3E30411 5 0 FGD Project Wiring Diagram JBR Elect Bldg DCS I/O Cabinet 3104 Base 1

• E3E30411 1 1 FGD Project - Wiring Diagram JBR Elect Bldg DCS I/O Cabinet 3103 Power Supply

• E3E30411 2 3 FGD Project - Wiring Diagram JBR Elect Bldg DCS I/O Cabinet 3104 Base 0








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Number Sheet Rev Title Loop Sheets

• 3BIWFF5161 1 0 Loop Sheet JBR Mixer 1 Seal Water Low Flow WF-FISL-5161




• B3ISKL5021 1 0 Loop Sheet JBR Narrow Range Level SK-LIT-5021A/SK-LIT-5021B/SK-LIT-5021C

• B3ISKL5022 1 0 Loop Sheet JBR Wide Range Level SK-LIT-5022A/SK-LIT-5022B/SK-LIT-5022C

Functionals

• D3F01110 1 0 JBR Mixer 1 Functional Control Diagram




• D3F01114 1 0 JBR Mixer Logic Functional Control Diagram

• D3F01115 1 0 JBR Mixer 1 Lube Oil Pump Functional Control Diagram




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Number Sheet Rev Title Vendor Drawings

• R280947-K 1 A 783 Gear Drive External Lubrication System With Heater Exchanger

Vendor O&M Manuals

• S81432 1 0 Scrubber - FGD - Mist Elimination System - Operation & Maintenance Manual




• S82591 1 0 Scrubber FGD - JBR Absorber Agitators - Assembly Drawing - External Lube System

Procedure Revision Summary

Revision Document Change:

0

Initial issue of document.

1

2

NOTE: See Revision Bars for specific changes within document.

PLANT BOWEN UNIT 3 FLUE GAS DESULFURIZATION … · DCS when the FGD Absorber Bypass Damper is not...

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