Method for reducing nitrogen oxides from the exhaust gas of a coke oven

Abstract

The invention relates to a method for reducing nitrogen oxides from the exhaust gas of a coke oven, which has a plurality of coking chambers and heating walls, arranged between the coking chambers, with heating flues (12, 12') for the indirect heating of the coking chambers. A combustible gas (16), which consists entirely or partially of coke oven gas, is burned in the heating flues (12, 12'), thereby producing an exhaust gas which contains nitrogen oxides. A reducing agent is fed to the exhaust gas at a temperature between 700 DEG C and 1100 DEG C and the proportion of nitrogen oxide in the exhaust gas is reduced by a homogeneous gas reaction between the reducing agent and the nitrogen oxides. The exhaust gas is subsequently passed through a regenerator (4) for heat recovery. Furthermore, carbon deposits on hot parts of the combustible gas feed are burned with decarbonizing air, wherein, during a regenerator half-period in which the combustible gas feed to one heating flue (12') is stopped, the decarbonizing air is introduced into this heating flue (12') through the associated burner supply line and combustible gas nozzle (15') and is discharged from another heating flue (12) with the hot exhaust gas. According to the invention, metered amounts of the reducing agent are fed into the decarbonizing air and, together with it, brought into contact with the hot exhaust gas.

Description

Technical field [0001] The present invention relates to a method for reducing nitrogen oxides in the exhaust gas of a coke oven. The coke oven has a plurality of coking chambers and a plurality of coking chambers with hot air passages for indirect heating of the coking chambers. Heating the wall. The fuel gas is burned in the hot air channel and produces exhaust gas, which contains nitrogen oxides, and the fuel gas is wholly or partly composed of coke oven gas. The reducing agent is input into the exhaust gas at a temperature between 700°C and 1100°C, and the nitrogen oxides in the exhaust gas are reduced by a homogeneous gas reaction between the reducing agent and nitrogen oxides. The exhaust gas is then directed to flow through a regenerator for heat recovery. Background technique [0002] One such method is known from EP 0 217 045 A2. In the known method, the reducing agent is sprayed or blown into the interior of the regenerator above the layer of packing material. For th...

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