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(2) Pneumatic ball valve FCV-*V2 for liquid is closed. (3) PID controller for liquid is disabled. (4) Atomizing air valve FCV-*V3 remains open. (5) After operational readiness is achieved and the control room has switched the injection system on, the system begins injecting as long as aqueous ammonia is required. Normal Operations The aqueous ammonia 19%SCR system runs 24 hours a day, 7 days a week. There are no normal operations associated with the system other than regular system inspections. (1) Visually inspect the equipment in the system once per shift. (See the operator's shift rounds and the Maintenance Section) (2) Record all maintenance and repair work on the system. (3) Record all preventative maintenance work using the CMMS. (See the Maintenance Section) Normal Shutdow NOTE: Normally the system will never be shut down unless there is a leak or maintenance needs to be performed on the equipment. NOTE: The liquid side must always be completely shut-down before the air side is closed. (1) Injection of liquid can be stopped by either result of a low NOx level downstream or a change in the operation mode. (2) If the NOx level downstream trends in the decreasing direction,the control valves FCV*V1 will close at a rate defined by the PID control loop. The liquid flow rate is reduced until valves FCV*V1 are closed. (3) If the NOx level falls below the limiting valve or the liquid control valve is closed, the running pump is shut down and the pneumatic actuated ball valve FCV*AV2 is closed. Atomizing air should continue to be injected. (4) If necessary, shut off the pumps. This can be done through the control system or by activating the Emergency Stop Button. (5) Close the flow control valve. (6) Run the flush sequence, sending waterto the exhaust and removing any residual aqueous ammonia from the piping. (7) Once the flush sequence has completed, maintenance can be performed on the system. (See the line opening procedure) If the system is to be shut down for a long period (weeks), the valve skid unit must be treated with preservation oil to protect internal components. To prevent water hammer and for faster startup, it is recommended to leave the piping filled during system standstills. Temporary Operations There are no Temporary Operations associated with the aqueous ammonia 19% SCR system. If Temporary Operations are required at a later date, the procedure(s) will be documented by the Page I B-4