return water system - southern company plant … safety considerations 1. all operating companies...

BWN-02602.201 Rev 1 Process Description Plant Bowen

Date Printed 2/22/2011 of 40

/s/ Gary Smith Approved Plant Review Board /s/ Tim Crump Approved Operations Manager /s/ Tim Banks Approved Plant Manager Date: 11-16-2010

PLANT BOWEN UNITS 1, 2, 3, & 4 FLUE GAS DESULFURIZATION SYSTEM

RETURN WATER SYSTEM PROCESS DESCRIPTION Document No. 2602.201

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.

BWN-02602.201 Rev 1

Date Printed 2/22/2011 of 40

T able of C ontents

2602.101 PROCESS DESCRIPTION 3

2602.101.1 Safety Considerations 3

2602.101.2 Process Flow Description 4

2602.101.3 Process Description 5

2602.101.3.1 Introduction 5

2602.101.3.2 System Components 6

2602.101.3.2.1 Return Water Tank (WR-TK-5400A & B) 7

2602.101.3.2.2 Return Water Pumps (WR-PU-5410A & B) 9

2602.101.3.2.3 Return Water Tank Mixers (WR-MX-5400A/B) 14

2602.201.3.2.4 Return Water Recirculation Valve (WR-FV-5416) 20

2602.201.3.2.5 Return Water Pump Discharge Valves (WR-XV-5412A/B) 23

2602.201.3.2.6 Return Water Flow Meter (WR-FE/FIT-5416) 24

2602.101.3.3 Summarized Controls Description 27 2602.101.3.4 Detailed Controls Description 28

2602.101.4 Process Flow Description 30 2602.101.5 Drawing References 35

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Confidential Information of 40

2602.101 PROCESS DESCRIPTION 2602.101.1 Safety Considerations

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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2602.101.2 Process Flow Description

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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2602.101.3 Process Description 2602.101.3.1 Introduction

The return water subsystem collects, stores, and transports water recovered by the vacuum filters for reuse by the limestone handling subsystem. The subsystem consists of two tanks, two return water pumps, two return water tank mixers, control valves, level instrumentation, and other equipment. Two return water tanks are provided for Units 1, 2, 3 & 4. Vacuum filter filtrate is transferred to the return water tanks located in the gypsum dewatering area. The return water pumps serve both return water tanks transporting the return water on demand to the limestone handling ball mill circuits and throughout the FGD system for flushing of slurry pipelines. Under normal operating conditions, both return water tank are in service. The return water tank fill valve will open at 16’ tank level and close at 18’ tank level.

RW Tank A

RW Tank B

Dewatering Train Dewatering Train Dewatering Train

Unit 1 Unit 2 Unit 3 Unit 4

Return Water Tanks & Pumps Configuration

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2602.101.3.2 System Components

The Return Water System consists of:

• Two Return Water Tanks

• Two Return Water Pumps

• Two Return Water Tank Mixers

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2602.101.3.2.1 Return Water Tank (WR-TK-5400A & B)

Number Sheet Rev Title P&IDs

• D1M20038 1 6 FGD Project P&ID U1 - U4 Return Water System

F unc tion

The return water tank collects and stores filtrate from the gypsum dewatering process and reclaimed return water. The return water reserve is supplemented with make-up water as needed. Des c ription

Return Water Tanks (WR-TK-5400A & B) are located adjacent to the dewatering building. Each tank measures 49’ high, 46’ in diameter and are constructed of fiber reinforced plastic. Each tank has a total capacity of 609,000 gallons with a normal working capacity of 410,000 gallons. Only one tank is normally in operation at a time. The working volume of the tank provides for approximately 468 minutes (7.8 hours) of water supply during design operating conditions.

Quantity 2

Dimensions, H x D 49’ x 46’

Total Capacity 609,000 gallons

Working Capacity 410,000 gallons

Working Retention Time 7.8 hours @ design condition

Construction fiberglass reinforced plastic

Cover None

Impeller Type 1 impeller, 3 blades per impeller

Impeller Diameter 128”

Impeller Speed 20.2 rpm, 846.1 fpm

Impeller Materials Carbon steel w/ 3/16” natural rubber coating

Impeller Elevation 128”

Minimum Tank Mixing Level 168”

Tank Inflows Filtrate pumps and make-up water

Tank Outflows Return water pump, overflow

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2602.101.3.2.1 Return Water Tank (WR-TK-5400A & B)

The return water tanks are equipped with a level control system providing continuous level measurement as well as alarms and interlocks. The level in these tanks regularly rises and falls in accordance with the frequency of the gypsum dewatering and ball mill operations. A minimum operating level is maintained by the addition of make-up water through the return water tank make-up valve. This valve operates around a level of 16 ft with a 2 ft dead band. That is to say that the valve opens once the tank level falls to 8 ft and closes when the level rises to 18 ft. This provides the supplemental water needed to support the limestone handling subsystem and ensures return water availability for flushing and other demands. The addition of make-up water to the return water tank must be monitored. Too much make-up water here can unbalance the FGD system water balance. The figure below illustrates the return water tank level alarms and interlocks.

The operator selects via the DCS which tank is to receive filtrate from the dewatering trains and which tank is to provide water to the selected return water pump.

47 ft

14 ft

16t

6 ft

High Alarms

Stops/Start Permit Mixer

Make-up Water Addition Control

Low- Alarms, Stops/Start Permit Pump

Return Water Tank Level Alarms & Interlocks

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2602.101.3.2.2 Return Water Pumps (WR-PU-5410A & B)


• D1M20038 1 6 FGD Project P&ID U1 - U4 Return Water System Vendor O&M Manuals

• S80769 1 A Scrubber - Flue Gas Desulfurization - Component Drawing - Return Water Pumps

• S80836 1 0 Scrubber - Flue Gas Desulfurization - Flange Loads - Limestone Slurry Transfer/Gypsum Transfer/Return Water Pumps

• S92422 1 0 Scrubber-Flue Gas Desulphurization-Installation, Operation & Maintenance Manual - Return Water Pumps

F unc tion

The return water pumps pump return water from the return water tank to be distributed throughout units 1, 2, 3 & 4 return water distribution header systems. Des c ription

Pumps The return water pumps are centrifugal manufactured by Weir Slurry, model number 10/8FAH QQQM. The pumps have a flow rate of 3,300 gpm with an operating head of 265ft of water. The casings are constructed of ductile iron and lined with natural rubber for added wear protection. Drive shafts constructed of 1045 steel are attached to high chrome alloy impellers. A reverse overhead ZV pump/motor drive arrangement provides motor support for ease of maintenance. The pumps are driven via poly chain configuration reducing the motors normal output speed of 1,770 rpm to a pump normal operating speed of 959 rpm. A common recirculation line routed back to the return water tanks provides the minimum flow required for pump operation. The pumps are of slurry design but because of the very low solid content of return water, they are equipped with manually operated drains and not automatic.

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Typical Weir Slurry Pump

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Motors The return water pump motors are manufactured by Teco-Westinghouse frame 449T. 460V, 3-Phase Induction motors rated at 350hp. Each motor is equipped with variable speed control allowing the pumps to operate over a wide range of flow demands.

Teco-Westinghouse frame 449T Motor

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Gear Boxes The return water pump use a Faulk size 325 gear box.

Typical Falk Gear Box

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Pump VFD The pump motor is controlled through a Powerflex 700H Adjustable Frequency AC Drive.

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2602.101.3.2.3 Return Water Tank Mixers (WR-MX-5400A/B)



• S82441 1 B Scrubber - FGD - Agitator - Return Water Tanks (Large) - Mixer Installation, Operation & Maintenance Manual

F unc tion

The return water tank mixers serve to prevent sedimentation inside the tanks and maintain what solids there may be inside the tank in a uniform distribution throughout the tank’s volume. Des c ription

The mixer assemblies are top mounted above the Return Water Tanks. The mixers are manufactured by Lightnin of model number 780Q25. The mixer shaft is constructed of carbon steel with a 3/16” natural rubber coating to minimize wear and prevent corrosion. The impeller consists of three blades creating a diameter of 128”. The impeller rotates at a speed of 20.2 rpm which at the impeller tip translates to 676.9 fpm or 7.7 mph. The impeller is also constructed of carbon steel with a 3/16” natural rubber coating. The motive force for the mixer is the output of a 25hp motor transmitted through a gearbox also manufactured by Lightnin. The impeller is located 128” above the floor of the Return Water Tank. Minimum tank level for operation of the mixer is 168”.

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Gear Box

The Mixer impeller is powered by a Lightnin model 780 gear box.

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Motor

The Mixer is powered by a TEFC 480V, 25HP, 1200 RPM horizontal mounted motor. Frame number 324T.

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Impeller

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2602.201.3.2.4 Return Water Recirculation Valve (WR-FV-5416)



• S92122 1 0 Scrubber - FGD - Control Valves - 4 Durco Lined Ball Valve - Return Water Recirc. Control Valve

• S92130 1 0 Scrubber - FGD - Control Valves - MORIN MRP Pneumatic Rack & Pinion Actuator Instructions - LS-DV-5535/5545, WR-FV-5416

F unc tion

The Return Water Recirculation Valve (WR-FV-5416) provides a path for recalculating return water back to the storage tanks. Des c ription

The Header Recirculation Valve is a 4” Tyco Morin Durco Polypco lined ball valve, P/N, AKH3-PP / MPR K037SR / KE / 6030H / F&R 150 # RF flanged body. Polypropylene lined body. Encapsulated disc and stem. PTFE seat and seals.

Valve is a fail open type with a Morin MPR K 037SR single acting spring return actuator and a Fisher 6030H positioner.

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2602.201.3.2.4 Return Water Recirculation Valve (WR-FV-5416)

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2602.201.3.2.4 Return Water Pump Suction Valves (WR-XV-5411A/B)



F unc tion

The Return Water pump suction valves (WR-XV-5411A/B) provides isolation for the suction side of the Return Water Pumps. Des c ription The Return Water pump suction valves (WR-XV-5411A/B) are fail open, 12” butterfly valves manufactured by Keystone.

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2602.201.3.2.5 Return Water Pump Discharge Valves (WR-XV-5412A/B)



F unc tion

The Return Water pump discharge valves (WR-XV-5412A/B) provides isolation for the discharge side of the Return Water Pumps. Des c ription

The Return Water pump discharge valves (WR-XV-5411A/B) are fail open, 12” butterfly valves manufactured by Keystone.

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2602.201.3.2.6 Return Water Flow Meter (WR-FE/FIT-5416)



• S94531 1 A FGD - Scrubber - Gypsum Dewatering Controls - Flow Transmitter Magmeter

• S94886 1 0 FGD - Scrubber - Gypsum Dewatering Project - AXF - Magnetic Flowmeter - Integral Flowmeter - Remote Flowtube

F unc tion

The function of a Return water flow instruments (WR-FE/FIT-5416) is to provide flow indication to the DCS for level control.

Des c ription

The Return Water flow meter consists of a flow element and a flow transmitter. The flow element is a model AXF250G-PNAH1H-AA11-2NB/SCT/X1 magnetic tube type inductive flow element manufactured by Yokogawa. It is coupled a Model AXFA14C-E1-21/A/SB/SCT flow transmitter also manufactured by Yokogawa.

A magnetic flow meter has a tube for supporting fluid flow and a circuit for indicating when the tube is empty. The circuit includes an amplifier connected to two electrodes in the tube and a variable resistor. The amplifier produces an oscillating signal when the tube is empty. The circuit is calibrated for a particular fluid by finding a range of resistances for the variable resistor at which the circuit provides an accurate indication that the tube is empty, and storing information in the processor indicating a resistance in the range for the fluid.

Magnetic flow meters measure the rate of flow of a process fluid through a tube. Magnetic coils mounted on opposite sides of the tube produce a magnetic field perpendicular to the direction of fluid flow in the tube. Electrodes placed in the tube measure a resulting current in the fluid that is perpendicular to both the direction of fluid flow and the magnetic field. A processor converts the output of the electrodes to a measure of the rate of fluid flow.

http://www.patentstorm.us/patents/5895864-fulltext.html�

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The AXF magnetic flow meter has been developed based on Yokogawa's decades long experience in magnetic flow meters. It offers outstanding reliability and ease of operation. The AXF magnetic flow meter is significantly easier to maintain thanks to the combination of replaceable electrodes and a diagnostic function that detects the level of coating on the electrodes. The AXF also employs a dual frequency excitation method (available for sizes up to 16 in.) that eliminates fluid noise. A newly enhanced dual frequency excitation method is also available as an option for more difficult applications to ensure greater stability and quicker response.

Typical Yokogawa flow meter

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2602.101.3.3 Summarized Controls Description

Operation of the return water pumps is initiated by the operator via the DCS. Permissives for operation include a return water tank level greater than the low-low level alarm. Two return water pumps are provided. One is operating and one is stand-by. The selected pump starts upon operator’s initiation and stops upon a low tank level or at operator’s command. Note that these pumps operate at tank levels where the return water tank mixer is not in service. This is possible due to the low solids loading of the return water. The stand-by pump starts automatically on the trip of the primary pump.

Return water pipeline pressure is maintained at setpoint by speed control of the pump. Minimum pump flow is protected via a flow monitoring element and flow control valve installed in the recirculation pipeline. Once the measured pump flow falls below the minimum flow setpoint, the minimum flow control valve opens and modulates to control flow to the setpoint. The return water tank fill valve will open at 16’ tank level and close at 18’ tank level.

Start Permits

• No return water pump currently operating

• Selected return water tank level greater than low alarm

• Selected return water tank valve is open

• Suction valve open

Operating Interlocks (Trips)

• Selected return water tank level less than low alarm

• Return water pump motor current draw greater than high alarm

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2602.101.3.4 Detailed Controls Description

Control of pump operation is accomplished automatically, stepping through the DCS sequencing logic. Provisions for manual stepping and resetting for maintenance and troubleshooting are included. Each pump has two auto-actuated valves; suction and discharge. These valves are cycled to perform starting and shut-down actions. The return water pumps do not require flushing. They are only equipped with manual drain valves.

The suction and discharge valves have open and close graphical pushbuttons. These allow the operator to operate the valves directly if needed. Pumps have start, stop, and lock-out pushbuttons. When in locked out, a pump is prevented from auto starting. When a pump is not running and not locked out, it is available for auto starting in the event of a failure of an operating pump.

An outline of return water pump start and stop actions are as follows: Pump Start 1. Pump is stopped with the suction and discharge valves closed. 2. A pump start is initiated by the auto start return water sequence logic, or manually

by the operator at the DCS. 3. Suction valve is opened 4. The pump motor is then started. 5. The discharge valve is opened (complete in 15-30 seconds). 6. The pump is now in the run mode. Pump Stop 1. Pump is running. 2. pump start is initiated by the auto start return water sequence logic, or manually by

the operator at the DCS. 3. The pump motor is stopped. 4. The suction valve is closed. 5. The discharge valve is closed 6. Pump is stopped.

When a pump starts, the suction and discharge valves are operated as described above. In order to protect the pump, the suction valve open position limit switch must be satisfied to close the pump motor contactor.

The return water tank fill valve will open at 16’ tank level and close at 18’ tank level.

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2602.101.3.4 Detailed Controls Description

Once the pump motor contactor closes, the pump discharge valve opens. Failure to satisfy the pump discharge valve open position limit switch results in an alarm. During pump operation, loss of a valve position limit switch signal is only an alarm.

Alarms associated with pump controls are the following:

• Pump abnormal trip

• Pump fails to start

• Alarm- Suction valve fault (failure to satisfy limit switch after 20 seconds)

• Alarm- Discharge valve fault (failure to satisfy limit switch after 20 seconds)

While failure to satisfy an open limit switch aborts a pump start it does not trip an operating pump. Pump motors are monitored and alarmed based on data across the MODBUS interface. Tripping for high current draw is performed by the SEL motor protection relays, totally independent of the DCS. When the SEL motor protection relays trip a motor, it closes a relay which is wired to a DCS contact input for alarm and indication of what caused the trip. High amp draw is an operations trip for all pumps.

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NOTE: System flow is only shown through one component/header when multiple components/headers have identical flow.

Process Flow

S tep 1.

Return water from the dewatering plant is supplied through a 12” header. The return water is directed through two independent legs each fitted with 6” butterfly valves (WR019 and WR020). The 6” legs terminate at return water tank (WR-TK-5400A and B). Reference Drawing No. D1M20038, Sheet 1, Rev. 6, FGD Project P&ID – U1-U4 Return Water System.

S tep 2.

Makeup water flows through an 8” header past 4” manual drain valve (MU260) before branching off into two 8” headers. Makeup water flows past an 8” manual fill line equipped with 8” manual fill valves (MU040 / MU223). Makeup water then flows through 8” valves (MU221 / MU222) before passing through 6” control valves (WR-XV-5401A / B) and empties into return water tanks (WR-TK-5400A and B). Reference Drawing No. D1M20038, Sheet 1, Rev. 6, FGD Project P&ID – U1-U4 Return Water System.

S tep 3.

Each return water tank is equipped with an 8” overflow line, located at the top of the tank. Each return water tank is equipped with 4” and 8” drain outlets located at the base of the tanks. The drains are fitted with manually operated 8” (WR065 / WR064) and 4” (WR001 / WR062) butterfly valves. The drains are routed to the Dewatering Facility Sump (WW-SU-5390). Reference Drawing No. D1M20038, Sheet 1, Rev. 6, FGD Project P&ID – U1-U4 Return Water System.

S tep 4.

Return water from each tank is drawn through 12” manually operated butterfly valves (WR-HV-5402A / B) to a 12” common header with a 12” tank header tie valve (WR132). Water then flows through two separate 12” headers to return water pump suction valves (WR-XV-5411A / B). Water is then directed past 2” drain lines equipped with 2” manually operated ball valves (WR004A / B) routed to dewatering facility sump (WW-SU-5390) before terminating at return water pumps (WR-PU-5410A and B). Reference Drawing No. D1M20038, Sheet 1, Rev. 6, FGD Project P&ID – U1-U4 Return Water System.

S tep 5.

Return water exits the return water pumps through 12” discharge headers. The return water pump discharge passes through check valves (WR002A / B) and return water pump discharge valves (WR-XV-5412A / B) before entering a 12” common header. Reference Drawing No. D1M20038, Sheet 1, Rev. 6, FGD Project P&ID – U1-U4 Return Water System.

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2602.101.4 Process Flow Description S tep 6.

The 12” common header directs water flow through manually operated butterfly valve (WR126) past flow element (WR-FE-5416) to 12” manually operated butterfly valve (WR127). Reference Drawing No. D1M20038, Sheet 1, Rev. 6, FGD Project P&ID – U1-U4 Return Water System.

S tep 7.

A 6” minimum flow recirculation line directs water flow through 6” manually operated butterfly valve (WR025) and control valve (WR-FV-5416) before passing through manually operated butterfly valves (WR031 / WR032) directing flow back to return water tanks (WR-TK-5400A / B) respectively. Reference Drawing No. D1M20038, Sheet 1, Rev. 6, FGD Project P&ID – U1-U4 Return Water System. S tep 8.

After the 6” recirculation header, the 12” header directs flow past two consecutive pressure transmitters (WR-PIT-5410A / B), before being routed to a 12” distribution header, a 10” header to the Ball Mill Area, and a 4” header to Limestone Slurry Transfer Pumps. Reference Drawing No. D1M20038, Sheet 1, Rev. 6, FGD Project P&ID – U1-U4 Return Water System.

S tep 9.

Along the 12” return water supply distribution header, several successive branch headers equipped with isolation valves, direct flow to the following systems:

• A 4” branch header supplies return water through a 4” manual isolation valve (WR056) to U3 Gypsum Drawoff Pumps

• A 4” branch header supplies return water through a 4” manual isolation valve (WR051) to Gas Cooling Pump Flush

• A 4” branch header supplies return water to U3&4 Limestone Slurry Storage Pumps

• An 8” branch header supplies return water through two 8” manual isolation valves (WR068 and WR061) to Limestone Slurry Transfer

• A 4” branch header supplies return water through a 4” manual isolation valve (WR047) to U3 Gypsum Drawoff Flush Water


• A 4” branch header supplies return water through a 4” manual isolation valve (WR049) U3&U4 Gypsum Slurry Transfer Pumps

Reference Drawing No. D3M20039, Sheet 1, Rev. 3, FGD Project P&ID – U3 & U4 Return Water Distribution.

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S tep 10.

From the 12” return water distribution supply header a 10” branch header directs flow through 10” manually operated butterfly valve (WR053) to six successive branch headers equipped with isolation valves directing flow to the following systems:

• A 4” branch header supplies return water through a 4” manual isolation valve (WR066) to U4 Gas Cooling Pump Flush Header

• A 4” branch header supplies return water through a 4” manual isolation valve (WR054) to U4 Gypsum Drawoff Pumps Header

• A 4” branch header supplies return water through a 4” manual isolation valve (WR052) to U4 Limestone Feed Wash

• A 6” branch header supplies return water through a 6” manual isolation valve (WR063) to U4 JBR Return Water


• A 4” branch header supplies return water to U3 Limestone Feed Wash Header Reference Drawing No. D3M20039, Sheet 1, Rev. 3, FGD Project P&ID – U3 & U4 Return Water Distribution.

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S tep 11.

From the 12” return water distribution supply header, a 10” branch header directs flow through 10” manually operated butterfly valve (WR033) to 12 successive branch headers equipped with isolation valves directing flow to the following systems:

• A 4” branch header supplies return water through a 4” manual isolation valve (WR041) to U1 Gas Cooling Pump Flush


• A 4” branch header supplies return water to U1 Limestone Feed Wash



• A 4” branch header supplies return water through a 4” manual isolation valve (WR042) to U2 Limestone Feed Wash


• A 4” branch header supplies return water through a 4” manual isolation valve (WR039) to U1&U2 Gypsum Slurry Transfer Pumps

• A 4” branch header supplies return water to LS Slurry Storage Pumps

• A 4” branch header supplies return water through a 4” manual isolation valve (WR045) to U2 Drawoff Flush Water

• A 4” branch header supplies return water through a 4” manual isolation valve (WR046) to Gas Cooling Pump Flush


Reference Drawing No. D1M20039, Sheet 1, Rev. 3, FGD Project P&ID – U1&U2 Return Water Distribution.

S tep 12.

The 10” header directs flow to the Ball Mill Area through 10” manually operated butterfly valve (WR060) and pressure regulating valve (WR-PRV-5416) before terminating at a 10” common header. Reference Drawing No. D1M20039, Sheet 1, Rev. 3, FGD Project P&ID – U1 & U2 Return Water Distribution.

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S tep 13.

Along the 10” common header, several branch headers direct flow to the following:

• A 4” branch header supplies return water through a 4” manual isolation valve (WR333) to supply Mill Product Tank A Nozzle Flush and Mill Product Tank B Nozzle Flush

• A 6” branch header supplies return water to Mill Product Tank A

• A 4” branch header supplies return water through a 4” manual isolation valve (WR034) to Mill Product Pumps A

• A 6” branch header supplies return water to Classifier A Underflow

• A 6” branch header supplies return water to Mill Product Tank B

• A 4” branch header supplies return water through manual isolation valve (WR035) to Mill Product Pumps B

• A 6” branch header supplies return water to Classifier B Underflow Reference Drawing No. D1M20039, Sheet 1, Rev. 3, FGD Project P&ID – U1 & U2 Return Water Distribution.

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2602.101.5 Drawing References

The Return Water System is illustrated on the following drawings:


• D1M20006 1 1 FGD Project P&ID Gas Cooling Pumps • D1M20009 1 3 FGD Project P&ID Jet Bubbling Reactor JBR Piping

• D1M20016 1 6 FGD Project P&ID Limestone Hydrocyclone A and Mill Product Tank A

• D1M20020 1 5 FGD Project P&ID Limestone Hydrocyclone B and Mill Product Tank B

• D1M20027 1 4 FGD Project P&ID Limestone Slurry Transfer System • D1M20029 1 0 FGD Project P&ID U1 JBR Limestone Feed • D1M20030 1 1 FGD Project P&ID U1 Gypsum Drawoff Pumps

• D1M20031 1 2 FGD Project P&ID U1 & U2 Gypsum Slurry Transfer Tank and Transfer Tank Pumps

• D1M20038 1 6 FGD Project P&ID U1 - U4 Return Water System • D1M20039 1 5 FGD Project P&ID U1 & U2 Return Water Distribution • D2M20006 1 1 FGD Project P&ID Gas Cooling Pumps • D2M20009 1 3 FGD Project P&ID Jet Bubbling Reactor JBR Piping • D2M20029 1 1 FGD Project P&ID U2 JBR Limestone Feed • D2M20030 1 2 FGD Project P&ID U2 Gypsum Drawoff Pumps • D3M20006 1 3 FGD Project P&ID Gas Cooling Pumps • D3M20006 2 0 FGD Project P&ID Gas Cooling Pumps • D3M20006 3 0 FGD Project P&ID Gas Cooling Pumps • D3M20009 3 0 FGD Project P&ID Jet Bubbling Reactor JBR Piping

• D3M20028 1 3 FGD Project P&ID Units 3 & 4 Limestone Slurry Storage System

• D3M20029 1 3 FGD Project P&ID U3 JBR Limestone Feed • D3M20030 1 4 FGD Project P&ID U3 Gypsum Drawoff Pumps

• D3M20031 1 4 FGD Project P&ID U3 & U4 Gypsum Slurry Transfer Tank and Transfer Tank Pumps

• D3M20039 1 4 FGD Project P&ID U3 & U4 Return Water Distribution • D4M20006 1 3 FGD Project P&ID U4 Gas Cooling Pumps • D4M20006 2 0 FGD Project P&ID U4 Gas Cooling Pumps • D4M20006 3 0 FGD Project P&ID U4 Gas Cooling Pumps • D4M20009 1 3 FGD Project P&ID Jet Bubbling Reactor JBR Piping • D4M20029 1 3 FGD Project P&ID U4 JBR Limestone Feed • D4M20030 1 4 FGD Project P&ID U4 Gypsum Drawoff Pumps

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Number Sheet Rev Title Single Line Diagrams

• S94965 1 0 FGD - Scrubber -Plumbing -Dewatering Building -Electrical 480V Distribution Single Line Diagram

• S94001 1 A FGD - Scrubber -Plumbing -Dewatering Building -Electrical DG-MCMAA-5000 AND DG-MCMAB-5000 480V MCC Single Line Diagram

• S94002 1 A FGD - Scrubber -Plumbing -Dewatering Building -Electrical DG-MCMBA-5000 AND DG-MCMBB-5000 480V MCC Single Line Diagram

Elementary Diagrams

• S93774 1 B FGD - Scrubber - Gypsum Dewatering Project - Electrical - 480V Bus A Supply Cabling Section - Switchgear Breaker DC

• S95509 1 A FGD - Scrubber - Gypsum Dewatering Project - Electrical Elem. Diagram 480V Feeder Breaker To Return Water Pump B VF Drive

• S95188 1 0 FGD - Scrubber - Gypsum Dewatering Project - Electrical Elementary Diagram Return Water Tank B Mixer WR-MO-5400B

• S95189 1 0 FGD - Scrubber - Gypsum Dewatering Project - Electrical Elementary Diagram Return Water Tank A Mixer WR-MO-5400A

Wiring Diagrams

• S94146 1 B FGD - Scrubber - Gypsum Dewatering Project - GE Switchgear - 480V - Return Pump - B BKR Control CKT.

• S94170 1 B FGD - Scrubber - Gypsum Dewatering Project - GE Switchgear - 480V - Return Pump - A BKR Control CKT.

• S95654 1 A FGD - Scrubber - Gypsum Dewatering Project - Electrical Wiring Diagram 480V Switchgear Bus A DG-SGMA-5000

• S95655 1 0 FGD - Scrubber - Gypsum Dewatering Project - Electrical Wiring Diagram 480V Switchgear Bus B DG-SGMB-5000

Distribution Panels

• S94948 1 C FGD - Scrubber - Gypsum Dewatering Project - Electrical Panelboard Schedules

• S94950 1 0 FGD - Scrubber - Gypsum Dewatering Project - Electrical Panelboard Schedules

• E-153951-00-E-0350 1 A Electrical Panelboard Schedules

• S94027 1 D FGD - Scrubber - Gypsum Dewatering Project - Electrical Panelboard Schedules

BWN-02602.201 Rev 1



Number Sheet Rev Title Loop Sheets

• B1IWRX5401 1 0 Loop Sheet Return Water Tank A Level Valve WR-XV-5401A

• B1IWRX5401 2 0 Loop Sheet Return Water Tank B Level Valve WR-XV-5401B

• B1IWRL5400 1 0 Loop Sheet Return Water Tank A Level WR-LT-5400AA / WR-LT-5400AB

• B1IWRL5400 2 0 Loop Sheet Return Water Tank B Level WR-LT-5400BA / WR-LT-5400BB

• B1IWRZ5402 1 0 Loop Sheet Return Water Tank A & Tank B WR-HV-5402A / WR-HV-5402B

• B1IWRX5411 1 0 Loop Sheet Return Water Pump A Suction Valve WR-XV-5411A

• B1IWRX5411 2 0 Loop Sheet Return Water Pump B Suction Valve WR-XV-5411B

• B1IWRX5412 1 0 Loop Sheet Return Water Pump A Discharge Valve WR-XV-5412A

• B1IWRX5412 2 0 Loop Sheet Return Water Pump B Discharge Valve WR-XV-5412B

• B1IWRF5416 1 0 Loop Sheet Return Discharge Header Flow WR-FIT-5416 / WR-FV-5416

• B1IWRP5410 1 0 Loop Sheet Return Discharge Header Pressure A & B WR-PIT-5410A / WR-PIT-5410B

BWN-02602.201 Rev 1



Number Sheet Rev Title Functional Control Diagrams • D5F00950 1 0 Return Water Tank A Functional Control Diagram

• D5F00951 1 0 Return Water Tank A Functional Control Diagram

• D5F00952 1 0 Return Water Tank A Level Fill Valve Functional Control Diagram

• D5F00953 1 0 Return Water Tank A Mixer Functional Control Diagram

• D5F00955 1 0 Return Water Tank B Functional Control Diagram

• D5F00956 1 0 Return Water Tank B Functional Control Diagram

• D5F00957 1 0 Return Water Tank B Level Fill Valve Functional Control Diagram

• D5F00958 1 0 Return Water Tank B Mixer Functional Control Diagram

• D5F00960 1 0 Return Water Pressure Control Functional Control Diagram

• D5F00961 1 0 Return Water Discharge Pressure Control Functional Control Diagram

• D5F00962 1 0 Return Water Discharge Pressure Control Functional Control Diagram

• D5F00963 1 0 Return Water Pump Logic Functional Control Diagram

• D5F00970 1 0 A Return Water Pump Logic VFD Breaker Functional Control Diagram

• D5F00971 1 0 A Return Water Pump VFD Functional Control Diagram

• D5F00972 1 0 A Return Water Pump Logic Functional Control Diagram

• D5F00973 1 0 A Return Water Pump Valve Alarms, Logic Functional Control Diagram

• D5F00974 1 0 A Return Water Pump Suction Valve Functional Control Diagram

• D5F00975 1 0 A Return Water Pump Discharge Valve Functional Control Diagram

BWN-02602.201 Rev 1



Number Sheet Rev Title Functional Control Diagrams

• D5F00980 1 0 B Return Water Pump VFD Breaker Functional Control Diagram

• D5F00981 1 0 A Return Water Pump VFD Functional Control Diagram

• D5F00982 1 0 A Return Water Pump Logic Functional Control Diagram

• D5F00983 1 0 A Return Water Pump Valve Alarms, Logic Functional Control Diagram

• D5F00984 1 0 A Return Water Pump Suction Valve Functional Control Diagram

• D5F00985 1 0 A Return Water Pump Discharge Valve Functional Control Diagram

BWN-02602.201 Rev 1



Number Sheet Rev Title Vendor O&M Manuals

• S92122 1 0 Scrubber - FGD - Control Valves - 4 Durco Lined Ball Valve - Return Water Recirc. Control Valve


• S80769 1 A Scrubber - Flue Gas Desulfurization - Component Drawing - Return Water Pumps


• S80836 1 0 Scrubber - Flue Gas Desulfurization - Flange Loads - Limestone Slurry Transfer/Gypsum Transfer/Return Water Pumps

• S92126 1 0 Scrubber - FGD - Control Valves - DVC6000 Series FIELDVUE Digital Valve Controllers - Instruction Manual

• S92128 1 0 Scrubber - FGD - Control Valves -Fujikin Fine Ceramic Ball Valves - Operation & Maintenance Manual

• S92129 1 0 Scrubber - FGD - Control Valves - Worm Gear Actuators-Maintenance Instructions- LS-DV-5535/5545, WR-FV-5416

• S92130 1 0 Scrubber - FGD - Control Valves - MORIN MRP Pneumatic Rack & Pinion Actuator Instructions - LS-DV-5535/5545, WR-FV-5416

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

• S92422 1 0 Scrubber-Flue Gas Desulphurization-Installation, Operation & Maintenance Manual - Return Water Pumps

Procedure Revision Summary

Revision Document Change:

0

Initial issue of document.

1

Currently, the fill valve on each Return Water Tank opens at 10 feet and closes at 12 feet. While this provides adequate water in the RWTs for FGD usage, it is below the mixer blade minimum operating level. Mixers that are not running, lead to gypsum settling in the bottom of the tanks. The Return Water Pumps (whose suction is at the bottom of the RWTs) then discharge the gypsum into the JBR flush lines which eventually plug. By raising the fill valve open and close settings, we will stay above the 14 foot mixer permit allowing the mixer to keep the gypsum in suspension.

Recommendation: Increase Return Water Tank level to keep Mixers running. Raise the RWT fill valve open set-point to 16 feet and the close set-point to 18 feet.

2

NOTE: See Revision Bars for specific changes within document.

return water system - southern company plant … safety considerations 1. all operating companies...

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