Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
  • C10B21/00—Heating of coke ovens with combustible gases
  • C10B21/10—Regulating and controlling the combustion
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
  • C10B29/00—Other details of coke ovens
  • C10B29/02—Brickwork, e.g. casings, linings, walls

Definitions

• the invention relates to a method for operating a coke oven with reduced nitrogen oxide emission from the coke oven heating trains and to a coke oven for carrying out the method.
• - Coke ovens essentially consist of a plurality of coking chambers and coke oven heating trains arranged on both sides of the coking chambers.
• heavy gas or lean gas is burned in the coke oven heating trains, thus indirectly heating the coking chamber with the coking coal enclosed therein.
• nitrogen oxides are produced in the flame area, the equilibrium formation rates of the nitrogen oxides increasing exponentially with increasing temperature at given oxygen and nitrogen concentrations. In the non-equilibrium, which is the rule in practice, the education rates increase with the time spent.
• the nitrogen oxides formed during the combustion are therefore also called thermal nitrogen oxides. Emission of nitrogen oxides is disruptive for environmental reasons.
• the invention is based on the technical problem of specifying a method for operating a coke oven which works in an environmentally friendly manner and yet with high coking performance.
• the invention teaches a method for operating a coke oven with coking chambers and coke oven heating trains arranged on both sides of the coking chambers for indirect heating of the coking chamber, the heating-side walls of the coke oven heating trains at least partially with a high-emission coating made of at least one layer with a substance from the group " CrO 3 , Fe 2 O 3 , SiC "or mixtures thereof are provided, and the combustion in the coke oven heating trains is set with the proviso that the heating surface power compared to the heating surface power of the coke oven heating trains without high-emission coating is practically the same and that the nitrogen oxide emission compared to the nitrogen oxide emission Coke oven heating trains without high emission coating is reduced.
• - high emission coating means a coating, whose surface has an increased spectral emissivity compared to the spectral emissivities of conventional coke oven building materials.
• the usual coke oven building materials generally have spectral emissivities of considerably less than 0.7 in the relevant wavelength range.
• the invention makes use of the knowledge known per se that surfaces with high spectral emissivities can improve the kinetics of heat transport by better absorption of radiation in the IR range. In this case, however, the invention works in such a way that the improved kinetics of the heat transport from the heating trains into the coking chamber is used to maintain an unchanged high heating surface output with reduced temperature in the heating trains, in particular with a reduced flame temperature.
• the method according to the invention is particularly environmentally friendly due to the absolutely reduced nitrogen oxide emission.
• a cumulative contribution to the improved environmental friendliness is that the lowering of the flame temperature also saves fuel gas and consequently reduces carbon dioxide emissions.
• the fuel gas savings result from the reduced flame temperature, since losses are lower at lower temperatures.
• the method according to the invention works at least as economically as classic methods without environmental protection measures.
• the heating-side walls of the coke oven heating trains can easily be equipped with the high-emission coating will.
• a wall can be coated with a preferably aqueous slurry of at least one substance from the group mentioned, optionally with a binder, in one or more spray application process steps.
• a sintering process then takes place during the heating process of the coke oven, as a result of which a uniform and mechanically and thermally resilient high-emission coating is produced which is intimately connected to the wall.
• the building materials can alternatively already be factory-equipped with the high-emission coating.
• the procedure is such that the high-emission coating has a spectral emissivity in the wavelength range from 1 ⁇ m to 7.4 ⁇ m and at a surface temperature of the high-emission coating between 800 ° C. and 1400 ° C. of more than 0.7, preferably of more than 0.9.
• the nitrogen oxide emission of the coke oven heating trains is preferably reduced by more than 5%, preferably by more than 10%, most preferably by more than 40%, compared to the nitrogen oxide emission of the coke oven heating trains without high emission coating.
• the invention also relates to a coke oven for carrying out the method according to one of claims 1 to 3, with at least one coking chamber and with vertical coke oven heating trains arranged on both sides of the coking chamber for indirect heating of the coking chamber Combustion of strong gas or lean gas, the coke oven heating trains being equipped with walls made of a conventional high-temperature material and the heating-side walls of the coke oven heating trains being at least partially coated with a high-emission coating of at least one layer with a substance from the group "CrO 3 , Fe 2 O 3 , SiC" or mixtures thereof are provided.
• the high-temperature material can be a commonly used refractory material.
• the coke oven is designed such that the heating-side walls of the coke oven heating trains are only partially provided with the high-emission coating, the arrangement of the high-emission coating being chosen with the proviso that the heating surface power is practically uniform over the entire surface of the walls .
• high peak temperatures can be reduced in a manner which is disruptive with regard to the formation of thermal nitrogen oxides, and on the other hand that the vertical temperature distribution in the walls of the coke oven heating trains is homogenized.
• An even temperature distribution leads to a more even conversion of the coking coal to the end product.
• a predefined temperature profile can alternatively be set by arranging the high-emission coating.
• the surface of the high-emission coating is advantageously optically rough.
• Visually rough means here that the roughness-causing surface structures have dimensions in the range above the wavelength of the radiation to be absorbed. In this sense, an optically rough surface has a higher emissivity than an optically smooth surface. Test roughness ranged from 30 to 100 ⁇ m. The application of the coating did not lead to a reduction in the roughness down to the wavelength range of the radiation, which results in a roughness greater than 10 ⁇ m. As a result, extremely high spectral emissivities, for example in the range of 0.99, can be achieved.
• the required micro-roughness of the surface can be set up by working with a slurry of a very fine-grained substance from the group mentioned in the application of the high-emission coating.
• the layer thickness of the high-emission coating is expediently at least 150 ⁇ m, preferably in the range from 1 to 3 mm.
• the temperature in the coke oven heating trains can be reduced by 5 ° C, and even by 25 ° C and more, while the heating surface output remains the same.
• the reduction in the area of high combustion temperatures, ie in the immediate flame area can be significantly higher, for example at 40 ° C.
• Lowering the temperature by 5 ° C leads to a reduction in the formation rates of thermal nitrogen oxides of approx. 5%.
• a reduction of 40 ° C halves the formation rates of thermal nitrogen oxides.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• Combustion & Propulsion (AREA)
• Carbon And Carbon Compounds (AREA)

Priority Applications (1)

Applications Claiming Priority (1)

Publications (1)

Family

ID=8219249

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Cited By (4)

Citations (5)

• 1995
  • 1995-05-12 EP EP95107203A patent/EP0742276A1/fr not_active Withdrawn

Patent Citations (5)

Non-Patent Citations (1)

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