FURNACE ARRANGEMENT The proper arrangement of a boiler furnace for the burning of oil does not differ materially from one ar ranged for the use of coal, and the change from one to the other is simple and inexpensive.
The fitting will naturally depend on the type of boiler and the burner to be used. Vertical water tube boilers will require a slightly different construc tion from that suitable for horizontal boilers of water tube or tubular type.
In general, the construction will consist in covering the grate bars with a good grade of fire-brick, leaving a suitable air space directly under and in front of the tip of the burner. The area of air space will depend upon the available draft as well as the size of boiler, etc. The burner is usually placed through an opening in the fire door space, which space has been closed by fire-brick. Beyond the air opening the fire-brick on the grate bars should be laid loosely for a distance of two or three feet and about i8 inches wide, to permit air to filter up through.
The regulation of air should be done by the damper and also by the ash-pit doors. Some engineers prefer to divide the ash-pit horizontally into two sections by fire-brick, bringing the air in through the lower and returning through the upper passage to the air opening at the front of the furnace, thus raising the temperature of the air slightly. It is not generally believed that this construction increases the efficiency to any extent.
The target—which should always be used in order to have a heated mass in front of the burner; there by generating a gas and re-igniting immediately after a momentary stop in the flow—should consist of a fire brick checker-work about 38" to 40" from the tip of the burner and about is " to 18" high, so arranged as to prevent any oil particles from passing through it without striking the white hot brick.
Care should be taken to so construct the furnace and target as to prevent the flame striking the water heating surface of the boiler in such a way as to localize the heat. It is often advantageous to pro tect the bottom row of tubes in water tube boilers by specially constructed fire-brick. This is frequently done in coal burning furnaces.
The successful burning of oil fuel requires a larger furnace volume than coal, the essential requirement being the perfect intermingling of the finely divided oil particles with the air supporting combustion in an incandescent furnace. Hence, it is sometimes desirable to remove the grate bars entirely when changing from coal to oil.
Owing to the many designs of oil burners, piping and furnace arrangements on the market, it is impos sible in a publication of this kind to show cuts or sketches which would cover the peculiar requirements of all power plants. Moreover, it would be confusing to the prospective fuel oil user, who is perhaps not familiar with the subject, to determine just which installation would be productive of the most economi cal results for his particular plant.
The Texas Company has had a wide experience in all matters pertaining to the use of oil as fuel, and information or advice will be cheerfully given upon application.