US3430610A - Steam raising boilers and process for improving thermal efficiencies of such boilers - Google Patents

Steam raising boilers and process for improving thermal efficiencies of such boilers Download PDF

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Publication number
US3430610A
US3430610A US608407A US3430610DA US3430610A US 3430610 A US3430610 A US 3430610A US 608407 A US608407 A US 608407A US 3430610D A US3430610D A US 3430610DA US 3430610 A US3430610 A US 3430610A
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United States
Prior art keywords
magnesium
boilers
injection
nozzles
combustion chamber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US608407A
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English (en)
Inventor
Walter Halliwell
Frank Pitts
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Magnesium Elektron Ltd
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Magnesium Elektron Ltd
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Filing date
Publication date
Application filed by Magnesium Elektron Ltd filed Critical Magnesium Elektron Ltd
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Publication of US3430610A publication Critical patent/US3430610A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J7/00—Arrangement of devices for supplying chemicals to fire
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B37/00—Component parts or details of steam boilers
    • F22B37/02—Component parts or details of steam boilers applicable to more than one kind or type of steam boiler
    • F22B37/04—Component parts or details of steam boilers applicable to more than one kind or type of steam boiler and characterised by material, e.g. use of special steel alloy
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22G—SUPERHEATING OF STEAM
    • F22G5/00—Controlling superheat temperature

Definitions

  • the object of this invention is to achieve a controlled increase in superheat temperature without a simultaneous increase in excess air, or of permitting a reduction in excess air without reduction in superheat temperature.
  • sieve are injected into the boiler combustion chamber in a direction making an angle between 30 below the horizontal and 60 above the horizontal and in a plane (as seen in plan view) making an angle between 45 and 135 with the direction in which the fuel is injected, in such manner that a heat-reflecting layer of magnesium oxide is maintained on the surface of a predetermined section of the combustion chamber wall-tubes.
  • the oil may be injected from a plurality of ice fuel injection nozzles or burners in opposite directions or in the same direction while the magnesium may be injected in opposite directions across the fuel streams.
  • the position or each position of injection of magnesium in the combustion chamber wall may be located between the levels of the lowest and of the highest banks of fuel injection nozzles or burners.
  • Magnesium may be injected at more than one position but in the case of each injection position the angles referred to are applied in relation to the direction of fuel injection nearest to the position of magnesium injection.
  • the velocity with which the magnesium particles are injected and the size of the particles are preferably so chosen in relation to the combustion chamber dimensions and the gas flow existing within the chamber that combustion of the particles is substantially complete before the burning particles have fallen to a level below the lowest bank of oil burners and that no substantial proportion of the particles is carried out of the combustion chamber before combustion of the particles is complete.
  • the effect of this method of controlling the injection of magnesium particles is to produce a white deposit of heat-reflecting magnesium oxide on that area of the walltubes lying between the plane of the lowest bank of oil burners and a plane situated below the position at which the combustion gases leave the combustion chamber and enter the superheaters or reheaters.
  • the height of the band covered by magnesium oxide is varied according to the desired increase in superheat temperature and/or reduction in excess air and can be controlled by varying the velocity and angles of injection of the magnesium within the limits specified.
  • the increase of superheat temperature and/or reduction in excess air can also be varied by varying the reflectivity of the magnesium oxide coating which is controlled by varying the rate at which magnesium is injected.
  • the velocity and angles of magnesium injection are varied by trial until the rate of magnesium injection is the minimum consistent with the desired improvement in thermal efiiciency.
  • FIGURE 1 is a vertical section of an oil-fired boiler constructed in accordance with the invention
  • FIGURE 2 is a horizontal section on the plane 2-2 on FIGURE 1;
  • FIGURE 3 is a vertical sectional view of another form of boiler
  • FIGURE 4 is a sectional view on line 4-4 on FIG- URE 3;
  • FIGURE 5 is a sectional view on the line 5-5 on FIGURE 4.
  • a combustion chamber 10 is connected at its upper end by channel 8 to superheaters and/or reheaters 9.
  • the chamber 10 is formed by four walls 11, 12, 13, 14 and around all the walls are the usual water tubes 16.
  • Oil burner nozzles 17, 18 extend through the walls into the chamber 10 at an angle of to the plane of the wall in plan (FIGURE 2) so as to inject oil into the furnace in opposite directions. These nozzles in this example are in four banks (FIGURE 1).
  • Magnesium injection tubes or nozzles 20, 21, 22, 23 extend through the walls 11, 13 at an angle of 45 to the vertical, their outer ends being lowermost, and at 70 to the walls 11, 13 in plan and 20, 21 being at to nozzles 22, 23.
  • the magnesium oxide coating is produced on all four walls 11, 12, 13, 14 between a plane indicated by broken line 25 in FIGURE 1 between the lower two banks of oil burner nozzles 17 and a plane indicated by the broken line 26 which is below channel 8 through which the combustion gases leave the chamber 10.
  • the superheaters and reheaters 9 are above the chamber 10, the burner nozzles 17 enter the wall 14 in three banks, and the magnesium injection nozzle 20 enters the wall 11 at right angles (in plan) to the burner nozzles 17 and a similar nozzle 21 enters the wall 13 opposite to the nozzle 20 at the same angle to the vertical as in FIGURE 1.
  • nozzles 20, 21 are directed oppositely to each other from opposite walls of the chamber 10.
  • Nozzle 20 is at right angles (in plan) to nozzles 17, and nozzle 21 is at 75 to nozzles 17.
  • Nozzles 20, 21 are at 60 to the vertical.
  • the injection of the magnesium may be effected by means of the apparatus disclosed in our co-pending patent application No. 22,963 of 1964.
  • Example Magnesium in the form of solid granules was injected at the rate of 3 lb. per hour into the combustion cham ber of a boiler consuming 12 tons of crude residual fuel oil per hour. Before commencing injection of magnesium the boiler was operating with 7% excess air to produce superheated steam at a temperature of 517 C., although the boiler had been designed to operate at a superheat temperature of 525 C., using only 5% excess of air over the stoichiometrical amount required for combustion of the fuel. After varying the particle size of the magnesium granules and the rate, velocity and angle of their injection it was found that injection of 3 lb.
  • the heat-reflecting band of magnesium oxide extended for a height of about 20 feet from a position about 3 feet above the lowest bank of oil burners to about 6 feet below the channel leading to the superheaters.
  • the improvement comprising a plurality of fuel injection nozzles entering said chamber in a generally horizontal direction and means for injecting magnesium particles into said combustion chamber in the region of said injection nozzles, said magnesium injecting means comprising a plurality of injection nozzles arranged at an angle of between 30 below and 60 above a horizontal plane through said boiler and in vertical planes making angles between 45 and 135 with said fuel nozzles, whereby injection of said magnesium particles into said chamber forms on the surface of a predetermined section of the combustion chamber walls a heat-reflecting layer of magnesium oxide.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Metallurgy (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Combustion Of Fluid Fuel (AREA)
US608407A 1966-06-03 1967-01-10 Steam raising boilers and process for improving thermal efficiencies of such boilers Expired - Lifetime US3430610A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB24873/66A GB1132899A (en) 1966-06-03 1966-06-03 Process and means for improving thermal efficiencies of steam-raising boilers

Publications (1)

Publication Number Publication Date
US3430610A true US3430610A (en) 1969-03-04

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ID=10218611

Family Applications (1)

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US608407A Expired - Lifetime US3430610A (en) 1966-06-03 1967-01-10 Steam raising boilers and process for improving thermal efficiencies of such boilers

Country Status (6)

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US (1) US3430610A (fr)
DE (1) DE1551700A1 (fr)
DK (1) DK111424B (fr)
ES (1) ES336896A1 (fr)
FR (1) FR1509641A (fr)
GB (1) GB1132899A (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4577566A (en) * 1982-04-01 1986-03-25 Betz Laboratories, Inc. Method of conditioning fireside fouling deposits using large particle size amorphous silica
US4458606A (en) * 1982-04-01 1984-07-10 Betz Laboratories, Inc. Method of conditioning fireside fouling deposits using large particle size amorphous silica
US4796548A (en) * 1984-05-08 1989-01-10 Betz Laboratories, Inc. Method of conditioning fireside fouling deposits using super large particle size magnesium oxide

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Also Published As

Publication number Publication date
FR1509641A (fr) 1968-01-12
DK111424B (da) 1968-08-19
ES336896A1 (es) 1968-05-01
DE1551700A1 (de) 1970-04-30
GB1132899A (en) 1968-11-06

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