control valve shall fail closed on loss of air, power, or control signal.
Absorber inlet and outlet temperature, water control valve status, and
water feed rate shall be indicated at the main control panelboard. Each
atomizer shall be provided with a local control panel mounted in the
penthouse enclosure. Complete local controls, indicating lights and alarms
shall be provided. Controls for the two-fluid nozzle atomizers shall be as
follows: interlocks and automatic trips shall be provided to automatically
stop the atomizer due to low oil pressure, high oil temperature, high motor
temperature or high vibration level. Remote indication of atomizer
operating conditions and alarms shall be provided on the main control
panelboard. Atomizer start switches shall be provided both locally and
remote.
2.12.1.3
Baghouses
Primary control of the fabric filter baghouses shall be from the FGD system
panelboard located in the steam plant control room. Design the control
system for automatic control of each fabric filter baghouse as required to
ensure stable and reliable operation. Monitor status and position of
motors, dampers, valves, etc. at the main control board by a graphic
presentation. Design for automatic or manual start-up and automatic
verification of the operation of each component of the fabric filter
baghouse in sequence as required for proper operation of the system. The
automatic start-up sequence will be manually initiated. Design for
automatic or manual shutdown and automatic verification of the shutdown of
each component of the fabric filter baghouse in sequence as required for
proper shutdown of the system. Design for automatic and safe shutdown of
any malfunctioning part of the system without disrupting boiler operation
capabilities. Any effect on the steam plant due to system control changes
will be avoided or minimized. The cleaning cycle will be initiated by
measurement of pressure drop across total fabric filter baghouse, by timer,
or by manual switch. Initiation mode shall be switch selectable. A manual
selector switch will allow manual operation of the cleaning function for
any module for the purpose of extra cleaning of any module or in the event
of automatic sequence failure. Off-line cleaning of pulse-jet fabric
filter baghouse modules (normal) or on-line cleaning shall be available at
the selection of the operator. The automatic timer and manual selector
switch will be interlocked with an isolation switch located at the tube
sheet access doors to ensure isolation of the module for maintenance. The
automatic timer will bypass any module not in service. This bypass will be
accomplished without timing through the cleaning cycle for the module just
bypassed (no dead time). The cleaning timer will allow for adjustment of
the frequency and duration of cleaning cycles to obtain optimum bag
cleaning. The bypass mode selector for each fabric filter baghouse will be
functional for either automatic control and for manual control. The system
shall automatically bypass the fabric filter baghouse as required to
prevent moisture carryover from spray dryer. Monitor status of process and
equipment for abnormal operation, failure, trip, etc. and provide visual
and audible alarms. Alarm indication shall include, but not be limited to,
high temperature drop across the fabric filter baghouse, high-pressure drop
across fabric filter baghouse, cleaning system malfunction, high ash level
(with indication of which hopper is alarming) and low hopper temperature
(with indication of which hopper is alarming).
Graphic display shall include at a minimum the following indicating lights
(color of lens in parentheses):
a.
Inlet damper--OPEN (green).
SECTION 15864N
Page 83
Previous Page
