Abstract: The method of reducing a nitrogen oxides content of a flue gas generated on firing of a rich gas or combination coke oven having a plurality of heating walls forming dual heating flues, in which a single stage or multistage combustion takes place, and also having a plurality of regenerators for recovery of flue gas heat and preheating of an underfiring medium, includes the steps of mixing one portion of the flue gas drawn from one flue of the dual heating flues with the underfiring medium, gas and/or air, prior to or on admission to the other flue of the dual heating flues, or a regenerator connected with it, and circulating another portion of the flue gas additionally inside the dual heating flues.

Abstract: A clamping system for preventing detrimental tensile and shearing stresses in heating walls used for example as partitions in industrial furnaces, comprises clamping plates adjoining opposite end faces of a heating wall plate, yoke-shape beams facing each clamping plate and interconnected by cross tie rods, and pressing elements between the beams and the clamping plates. The bias of the pressing elements is adjusted so as to decrease from the center of the clamping plate towards the upper and lower edges of the heating wall plate, the material of respective clamping elements being selected such as to keep the interfering forces within the limits of 5 to 20% of the original clamping forces, the resultants of the clamping forces being directed to the marginal area of each clamping plate, and the roughness in excess of 2.5 millimeters between the clamping plate and the heating wall plate being reliably compensated.

Abstract: In a coking operation where the heating medium is introduced into the furnace by way of a bottom fire box and wherein heat exchangers are provided for the waste gases, the waste gas is passed through a plurality of parallel channels serving as said heat exchangers and the useful portion of the total system available for such exchange is reduced when the coking time is increased beyond the time required at normal operation.