Determination of Gas Flow Pattern in a Test Coke Oven Charge and Its Time Variation by Tracer Technique.

Abstract

The travel path of produced gas in a coke oven has always been of interest. However, few studies have been reported on this subject. In the present study, a tracer technique was employed for the determination of the path of gas in a test coke oven with width of 45 cm, and charge height of 85 cm. Three tubes were inserted horizontally from the coke side at 15.6 cm high (L) and at 0, 8 and 16 cm from the center of the width. Two kinds of tracer gas were uniformly introudced along the tubes. Other six tubes were also inserted at 36 (M) and 54 (H) cm high and at 0, 8 and 22 cm from the center, and the gas in the oven was withdrawn from their ends located at the center of the length of the oven. The gas sampling was conducted every two hours through the sampling tubes and from the exit ascension pipe, where the total flow rate of the produced gas was determined from the concentrations of tracers. Ar injected at L16 was hardly detected inside the charge (0 or 8 cm from the center) at the middle stage of carbonization. The flow rate of produced gas at the vicinity of the wall (22 cm from the center) was determined from mass balance of Ar assuming that all Ar flowed there. Rates of gas cross from the center side to the wall side was evaluated from the concentration profile of He introduced into the coal layer. At the middle stage, most of the produced gas passed upward in the coke layer and no cross flow was found. This phenomena were to be explained by large flow resistance of the plastic zone. At the last stage, both of the tracers were uniformly distributed all over the coke layer.