Page 65 - Boiler_Operators_Handbook,_Second_Edition

50 Boiler Operator’s Handbook

sure regulator, must be maintained constant and at in oil supply pressure is indicative of problems
a prescribed value for accuracy of boiler gas flow with fuel oil pumps, tank levels, variations in oil
meters and/or air fuel ratio. Changes in the gas viscosity or quality. Changes in burner oil supply
pressure supply pressure to boilers with parallel pressure can upset fuel air ratio.
positioning controls can alter the air fuel ratio and
must be monitored to prevent unsafe operating Operating hours: Recording the amount of time a piece
conditions. of equipment is operating can permit output and
input calculations as well as a record of the amount
Happenings: Anything that happens which is not nor- of time the equipment has been running. Logging
mal should be documented. An operator’s com- equipment start and stop times or operating hour
ment that he heard what sounded like a gunshot meter readings are invaluable for plant perfor-
proved beneficial in a later court case. Happenings mance analysis and maintenance scheduling.
must be recorded consistently to support the cred-
ibility of a single incident report in court. Outdoor air temperature: Preferably the high and low
outdoor air temperature should be recorded. The
Header pressure: In high pressure steam plants this is outdoor air temperature is a prime indicator of
the pressure that is controlled. Changes indicate heating and ventilation loads. Taking the high and
problems with controls, excessively large load low temperatures for a day permits calculating
changes and inadequate boiler capacity. Degree Days for the facility location. Sophisticated
recording devices can record the time the outdoor
Low water cutoff tests: (See testing) air temperature is within a given range to provide
bin data when desired. Bin data are records of the
Makeup water meter reading: The principal source number of hours the outdoor temperature was
of contaminants in boiler water is the makeup within a certain range, and they allow very accu-
water. If makeup is consistent and there is no rate evaluation of heating plants.
leakage of untreated water into the system (such
as a domestic hot water heating coil break) the Oxygen: Monitoring and maintaining a minimum oxy-
water chemistry should be consistent. A sudden gen content of the furnace gases is one good prac-
decrease in makeup is an indication of an external tice for maintaining efficiency. Usually, however,
coil break that can be returning untreated water the analysis is made of the stack gases. Recording
to the boilers. Monitoring makeup water permits oxygen readings can reveal problems with air to
extending time between water chemistry analysis. fuel ratio controls, damage to boiler casings or
The quantity of makeup has a significant impact burner problems. When available it should be re-
on energy consumption. Every gallon of cold, say corded regularly.
50°, makeup water that replaces 180° condensate
requires more than 1,000 Btu of additional heat Primary air temperature (coal firing): Too high a temper-
input. I consider this one essential, even in the ature will result in pulverizer fires, too low a tem-
smallest of plants and regardless if they are steam perature will result in pulverizer plugging because
or hot water. the coal is not dried adequately. The temperature
of the primary air (leaving the pulverizer) when
Makeup water pressure: This is a value that is seldom compared to the entering air (air heater outlet tem-
monitored because operators take the continuous perature) is indicative of coal condition, moisture
supply of city water for granted. Someday the city content, and/or pulverizer condition.
will disappoint you. Monitoring the pressure from
wells is more critical. Recirculated flue gas temperature: This temperature
should be monitored for changes that indicate
Makeup water temperature: Determines heat required fan seal leakage and stratification in boiler outlet
for makeup, see makeup water meter reading. ducts.

Oil supply pressure: Main oil supply and boiler oil sup- Reheater steam flow and inlet and outlet pressures and
ply pressures must both be monitored. Variation temperatures: On boilers equipped with reheaters