Plant Air

Question 1

With regards to the plant air compressor what is a surge?

Answer 1

Air flow through the impeller reverses. Pressure switch opens the unloader valve. The compressor will adjust the set point and load the compressor back to the system (once). If the compressor surges again the unloader valve locks open until locally reset at the PAC.

Question 2

What will cause a surge?

Answer 2

High temperature air around the Pac because the air is less dense, thus it cant draw enough air to overcome the pressure on the down stream side of the impeller. Mechanical problems.

Question 3

What loads are supplied by the Turbine air west header?

Answer 3

Chemistry Lab. Atomizing air to the PHB. Generator Purge (U2). Turbine lagging hose connections (U2). MUP. Screen house hose connections (U2). Chemical cleaning tank.

Question 4

What loads are supplied by the Turbine air East header?

Answer 4

Turbine room sump dilution header. EDG hose connections (U2). Service building hose connections.

Question 5

How dose the PAC regulate lube oil temp?

Answer 5

By using a three way valve the regulates the amount of oil that bypasses the lube oil cooler.

Question 6

What will start the PAC AUX lube oil pump?

Answer 6

Start up of the PAC. Low oil pressure. Low air pressure.

Question 7

What type of compressor is the PAC?

Answer 7

Centrifugal.

Question 8

What type of compressor is the CAC?

Answer 8

Dual action reciprocating piston.

Question 9

What is the flow path for the Control air system?

Answer 9

.

Question 10

What are the automatic actions an alarms for the plant air system?

Answer 10

• 97# plant air pressure low alarm
• 95# on plant header the standby PAC starts.
• 93# Plant air compressore discharge pressure low alarm.
• 90# on wet air reciever the CAC starts.
• 86# Header isolation valves close.
• 80# on control air header, the reactor must be manualy tripped.

Question 11

Describe the operation of the control air dryer regeneration cycle.

Answer 11

• Eight hour time
• One tower drying
• 10 minutes before switch, standby tower pressurizes
• At switch, ganged valves on inlet and outlet shift to the other tower
• 5 minutes later the used to be I/S tower depressurizes
• 15 minutes after switch the blower motor starts-heater energized and exhaust valve opens
• 3 ½ hour regeneration time
• §Heater and blower stop, exhaust valve closes
• Remains in standby for balance of 8 hours

Question 12

What are the consequences of loosing NESW as it pertains to the compressed air systems?

Answer 12

• PAC Surge
• CAC Low NESW Pressure Trip
• Many Alarms

Question 13

What is the flow path for the plant air system?

Answer 13