Page 155 - Boiler plant and distribution system optimization manual

140 Boiler Plant and Distribution System Optimization Manual

can be made after shutting down the boiler and Description
inspecting the path indicated for the gases caus- There is a difference between “operating”
ing the hot spot. and “managing” a boiler. To manage a boiler you
need more information than is generally avail-
able with standard instrumentation which only
gives information about “operating” conditions.
Section 10-4 Fuel flow, steam flow, temperatures and make up
water use all play an important part in knowing
Metering and Monitoring what is happening and tracking trends. A boiler
with only 5% utilization or with 300% excess air
or a stack temperature of 750°F will not be effi-
CHECkLIST - 4 cient but it will produce steam and for all practi-
Metering and Monitoring cal purposes be operating satisfactory. Likewise, a
sudden increase in make up water use may indi-
1. Improved instrumentation and analysis cate a large loss of energy in the distribution sys-
2. Monitor and manage with a microproces- tem somewhere. Good instrumentation is need-
sor based system. ed to identify these efficiency related problems.
3. Add a fuel flow meter to the boiler plant Plants should have the following instruments:
for each fuel.
4. Provide a steam flow (or feedwater flow) 1. Stack thermometers.
meter for each boiler. 2. Fuel meters for each boiler.
5. Monitor excess air, carbon monoxide and 3. Make up feedwater meters.
combustibles either continuously or by 4. Oxygen analyzers.
regular checks with portable analyzers 5. Run time recorder.
6. Install an opacity monitor for oil fired 6. Energy output-input metering,
units (smoke is unburned fuel) 7. Return condensate thermometers.
7. Monitor flame conditions by visual checks
through viewing ports The ideal scene would to employ a modern
8. Install fuel cost indicator on each boiler computerized monitoring system to continuous-
front (i.e.-$/year) ly check on performance. If this cannot be done,
9. Maintain calibration for steam flow me- then this minimum instrumentation should be
ters. considered. Performance should be tracked to
10. Insure make-up water meter is meet fuel reduction objectives. A simple formula
working and accurate can be used if proper instrumentation exists:
11. Insure condensate line thermome-
Btu OUTPUT x 100
ters are in place and accurate EFFICIENCY % = ——————————
12. Keep instrumentation and chart re- Btu INPUT
corders in good repair.
There are portable boiler efficiency analyzers
available which can be used to help assess the ef-
1. IMPROVED INSTRUMENTATION ficiency of your boilers. These range from simple
wet chemical analyzers to electronic flue gas ana-
Cost lyzers that can measure excess air, stack emissions
Low and stack (heat loss) efficiency at the touch of a
button. These instruments measure stack losses
Potential Savings but do not give information about overall plant
Moderate to 25% (plus) performance. Because the instrumentation at