3rd. Unless the boilers and furnaces are especially adapted for the use of this fuel, the boiler upkeep cost will be higher than if coal were used. This objection can be entirely obviated, however, if the installation is entrusted to those who have had experience in the work, and the operation of a properly designed plant is placed in the hands of intelligent labor.
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Many tables have been published with a view to comparing the two fuels. Such of these as are based solely on the relative calorific values of oil and coal are of limited [Pg 216]
[Pg 217] value, inasmuch as the efficiencies to be obtained with oil are higher than that obtainable with coal. [Table 47] takes into consideration the variation in efficiency with the two fuels, but is based on a constant calorific value for oil and coal. [This table], like others of a similar nature, while useful as a rough guide, cannot be considered as an accurate basis for comparison. This is due to the fact that there are numerous factors entering into the problem which affect the saving possible to a much greater extent than do the relative calorific values of two fuels. Some of the features to be considered in arriving at the true basis for comparison are the labor saving possible, the space available for fuel storage, the facilities for conveying the oil by pipe lines, the hours during which a plant is in operation, the load factor, the quantity of coal required for banking fires, etc., etc. The only exact method of estimating the relative advantages and costs of the two fuels is by considering the operating expenses of the plant with each in turn, including the costs of every item entering into the problem.
City of San Francisco, Cal., Fire Fighting Station. No. 1. 2800 Horse Power of Babcock & Wilcox Boilers, Equipped for Burning Oil Fuel
Burning Oil Fuel—The requirements for burning petroleum are as follows:
1st. Its atomization must be thorough.
2nd. When atomized it must be brought into contact with the requisite quantity of air for its combustion, and this quantity must be at the same time a minimum to obviate loss in stack gases.
3rd. The mixture must be burned in a furnace where a refractory material radiates heat to assist in the combustion, and the furnace must stand up under the high temperatures developed.