AA2 Process Control Manual COGA KEY PROCESS RESPONSIBILITIES Monitor and control NOx, CO and O2 emissions within consent limits Monitor and control COGA operation within process control limits Request technical assistance through Shift Manager if unable to control within consent limits Liaise with Power Station over steam supplies at start-up and shutdown of COGA Unit and significant rate changes Liaise with supplying plants (HMD, KA, AA2) over shutdown/start-up of COGA Initiate immediate action to correct SOC non-compliance Initiate alternative sampling/testing arrangements in accordance with Plant Procedures Manual Section 35 in the event that continuous monitoring equipment fails.
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AA2 Process Control Manual COGA STANDARD OPERATING CONDITIONS/OPERATING GUIDES COGA SOC/OG COGA PROCESS CONTROL LIMITS CONTROL VARIABLE
LOW 70
Deaerator Level
STANDARD OPERATING RANGE NORMAL HIGH 80 90
Deaerator Temperature (Local Indication)
100
~ 105
Deaerator Pressure
0.6
~ 1.0
IP Letdown Deaerator Set Point
0.5 0
LP Steam to Deaerator (from HMD)
UNITS %
CONSEQUENCE OF DEVIATION Low – Potential damage to BFW pump High – Potential to overflow Deaerator with hot water
°C
Low – Excessive corrosion of internal Surfaces
1.3
Bar
High – Potential to lift RV (1.72 Bar g)
0.5 – 0.6
0.6
Bar
Low – Reduced corrosion protection of Waste heat Boiler
6–9
10
Te/hr
High – IP Steam wastage
SOC’S
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AA2 Process Control Manual COGA CONTROL VARIABLE
LOW 45
Steam Drum Level
STANDARD OPERATING RANGE NORMAL HIGH 67 75
UNITS %
CONSEQUENCE OF DEVIATION High – Water in steam main and water hammer Low – Potential damage to Circ Pumps / Evap tubes
