Page 138 - Boiler plant and distribution system optimization manual

Over 100 Ways to Improve Efficiency 123

8. Improve control system accuracy with ing the cost advantages and problems associated
strong precision parts with different fuels can lead to informed deci-
9. Stack dampers sions.
10. Slow down exhaust flow
11. Wind deflector for boiler room vents Table 10.1—Energy conversion efficiencies with dif-
12. Vent caps on stacks ferent fuels. These numbers are typical but may vary
13. Low excess air burner with specific application.
——————————————————————
14. Oxygen enrichment
Fuel Oil No. 6 85% Lignite 80%
15. Oil-water emulsions
Fuel Oil No. 2 84% Bituminous 87%
16. Replace atmospheric burners with power
Natural Gas 80% Anthracite 90%
burners
Propane 84% Methane 81%
17. Flame retention head type burners
Wood 72% Hydrogen 77.5%
18. Multi-stage gas valves ——————————————————————
19. Reduction of fuel firing rate
20. Replace On/Off controls with modulating
controls
21. Convert to air or steam atomizing burners
22. Fuel oil viscosity management
23. Intermittent ignition devices
24. Prevent heat transfer surface fouling
25. Air preheaters Economizers and other
heat recovery equipment
26. Reduce radiation losses

1. FUEL SELECTION
Table 10.2—The price of steam per million Btus can
vary to a large degree considering basic fuel cost and
Cost
conversion efficiency. Unfortunately, this analysis is
Low cost, basically analysis and decision
only the tip of the iceberg and additional study may
making.
be needed. Each type of fuel requires different trans-
High cost, if major equipment change-out is portation to the plant and some like heavy oil, coal
involved. and wood require additional conditioning before
they can be burned.
Potential savings
Large When confronted with the choice of switch-
ing from natural gas to residual oil, a more de-
Description tailed study should be made. Notice that there are
The bottom line is producing steam for heat many hidden costs in the conversion to heavy oil
and power at the lowest cost possible. At first that should be considered. Figure 10.19 is a plus-
glance you might think that the “best buy” would point minus-point evaluation example. The (+) in
be using the fuel with the most Btus per dollar. front of an item means that it generally will be
This type of ranking would show that wood, coal a benefit and a (-) indicates that there are draw-
and heavy oil would be the best buy. backs or additional costs involved.
There is more to know about the situation Different costs will be appropriate for each
than Btus per dollar. There is also the conversion of these items at individual plants. The important
efficiency (Table 10.1) and related problems with thing is to be aware of the fact that a complete
transportation and pollution to consider. Know- analysis is needed. A simple overlooked fact is