Flow Direction and Resistance of Produced Gas in a One-dimensional Carbonization Apparatus

Abstract

The travel path of the gases in the coke oven has always been of interest. However, few studies have been reported. In the present investigation, the time variations of flow direction and flow resistance of the produced gas in the coal and coke layers were measured in an experimental one-dimensional carbonization apparatus simulating a commercial coke oven.
The coal packed in a quartz tube was heated from one side simulating the wall side of a commercial coke oven at a constant heating rate and then kept at constant temperature (1274 K). The other side corresponding to the center side of the commercial coke oven entered into the furnace lastly. The first series of runs were conducted by opening both sides of the tube. Most of the produced gas was evolved from the wall side except the last stage of t he carbonization. Small increase in the wall side pressure caused the drastic increase in the evolution rate from the center side at the first and latter middle stages. However, at the earlier middle stage of carbonization, most of the gas was evolved from the wall side even under this condition. In the second series of runs, one side of the tube was closed. The steep increase in the wall side pressure and the interruption of gas evolution were observed at the earlier middle stage of the carbonization, only when the wall side was closed. In the last series of runs, nitrogen was forcedly introduced through a thin layer from one side. Steep pressure increase was randomly observed when the layer was at around 773 K, irrespective of the flow direction of the nitrogen. In conclusion, at the earlier middle stage of the carbonization, a plastic zone at around 773 K existed between the main gas production zone and the end of the center side and the flow resistance of the zone was found to be large.