Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L10/00—Use of additives to fuels or fires for particular purposes
  • C10L10/04—Use of additives to fuels or fires for particular purposes for minimising corrosion or incrustation

Definitions

• the present invention relates to the reduction of undesirable combustion by-products in boilers, incinerators and similar plant.
• organic compounds containing metals such as lead, cobalt, manganese, copper, nickel and chromium chromium can under certain conditions function as soot destroyers or combustion aids and it has been proposed to add these metals to fuels to provide for more complete combustion of the fuel to C0 2 and H 2 0.
• soot destroyers or combustion aids it has been proposed to add these metals to fuels to provide for more complete combustion of the fuel to C0 2 and H 2 0.
• the relatively large amounts of these metals which must be added to the fuel to give a significant improvement causes the fuel to become so unstable that the catalytic properties of these metals cannot be used. This effect can be offset by adding stabilisers or antioxidents to the fuel but again, large amounts are required which renders this economically impractical and gives rise to further disadvantageous secondry effects.
• the present invention provides a combustion process comprising passing combustion air over an ignited fossil fuel in a combustion chamber and prior to or during combustion introducing into the combustion chamber finely divided iron oxide which acts during combustion to reduce the amount of solid combustion by- products deposited in flue passes and chimneys of the combustion chamber during the combustion process.
• the substance is introduced during the combustion process, although it may also be introduced prior to combustion in the fueld.
• a preferred substance is sesquioxide of iron (Fe 2 0 3) .
• the present invention stems from the unexpected discovery that the addition into the combustion zone of finely divided iron oxide particles alone or mixed with an inert material in small quantities significantly reduces the formation and deposition of scale, smut and other solid combustion by-products and also acts to reduce existing scale. This results in the maintenance of heat transfer rates for very much longer periods and improved plant performance than in the absence of the substance with consequent saving in fuel consumption and maintenance costs.
• Finely divided iron is introduced into the combustion chamber in any suitable manner, conveniently in the form of ferric oxide (Fe 2 0 3 ) or in some other form which converts to ferric oxide under the conditions in the combustion chamber.
• the substance is preferably blown into or over the combustion zone repeatedly over short periods of time at intervals as desired, as a fine powder during combustion either in the combustion air or separately.
• the quantity of ferric oxide required to achieve the desired effect is very small, depending on the quality and type of the fuel.
• the substance may alternatively or additionally be added to the fuel itself and although the substance is described as being added during'combustion it will be appreciated that quantities can be added prior to combustion.
• the substance may also be added continuously if desired and can be in the form of a powder, a suspension in a substantially inactive or combustible liquid, or in the form of small pellets.
• the dosage rate of the substance is a minimum of 0.1134 Kg (0.25 lbs) to 0.4536 Kg (1 lb) per tonne of coal consumed, or the therm equivalent of oil, gas and other fossil fuels, a preferred range being 0.1134Kg to 0-4536 0.4536 Kg (11b).
• the quantities of substance injected into the combustion chamber can be more easily controlled by first mixing the substance intimately with a neutral powder. This also aids dispersion of the substance throughout the chamber.
• a diluent powder composed, for example, of bentonite, synthetically organically modified bentonite, dolomite or calcined dolomite or other finely divided diluent powder which is inactive i.e. does not adversely affect the process of the present invention may be used.
• the overall effect therefore, is a cleaner combustion chamber, flue passes and chimneys resulting in the maintenance of the boiler at higher efficiency and performance for long periods with consequently lowered fuel costs, a significant reduction in the cost of maintenance and cleaning and reduction in smut emission due to entrainment.
• oxide means one or more of the following: a suboxide, oxide of known valency, super-oxide, peroxide, hydroxide, hydrated oxide or carbonate.
• a mixture of iron oxide (Fe 2 0 3 ) as 30% by weight in an inactive finely divided naturally occurring clay powder was injected into the combustion chamber of a Colifax Hot Water boiler in the proportion of 0.227 Kg (0.5 lbs) weight of the mixture to each tonne of coal consumed.
• the powder was injected every 3 hours for the requisite period to achieve the above dose rate.
• the boiler efficiency as measured by flue gas analysis and temperature method improved from 65% to 71% over a period of 6 days and was associated with the removal of substantially all the adherent scale.
• the reduction in the carbonacous content of the boiler flue passes was some 50% as measured in before and after conditions.
• Example 1 A mixture of iron oxide (Fe 2 0 3 ) as 25% by weight in an inactive powder was injected as for Example 1 into the combustion chambers of three Centrax coal-fired boilers over a period of 6 months.
• the boilers became free from adherent scale within the first 3 to 4 weeks and the flue deposits become,substantially free from soot and greasy smut which made them extremely free flowing and easily removed.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)
• Combustion Of Fluid Fuel (AREA)
• Air-Conditioning For Vehicles (AREA)
• Glass Compositions (AREA)
• Incineration Of Waste (AREA)
• Rear-View Mirror Devices That Are Mounted On The Exterior Of The Vehicle (AREA)
• Preparation Of Compounds By Using Micro-Organisms (AREA)
• Cylinder Crankcases Of Internal Combustion Engines (AREA)
• Solid Fuels And Fuel-Associated Substances (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=10544613

Family Applications (1)

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Cited By (1)

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Citations (4)

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• 1983
  • 1983-06-22 GB GB838316937A patent/GB8316937D0/en active Pending
• 1984
  • 1984-06-22 AU AU37417/85A patent/AU3741785A/en not_active Abandoned
  • 1984-06-22 GB GB08416184A patent/GB2142342B/en not_active Expired
  • 1984-06-22 DE DE8484304239T patent/DE3475320D1/de not_active Expired
  • 1984-06-22 AT AT84304239T patent/ATE38852T1/de not_active IP Right Cessation
  • 1984-06-22 EP EP84304239A patent/EP0130065B1/fr not_active Expired
  • 1984-06-22 JP JP59502479A patent/JPS60501669A/ja active Pending
  • 1984-06-22 WO PCT/GB1984/000222 patent/WO1985000181A1/fr not_active Ceased

Patent Citations (4)

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