Behavior of Carbon Adhesion on Aged Coking-chamber Walls to Pushing Load

Abstract

A common problem observed in aged coke plants is the increase in pushing load during the discharge of coke mass, arising from irregularities on the damaged coking-chamber walls. Usually, the chamber wall is partially covered with adhered carbon. Because carbon growth is influenced by a number of factors, the chamber wall has a complicated carbon adhesion distribution, and the amount of carbon-covered area differs from chamber to chamber. Carbon adhesion locally affects the pushing load both positively and negatively. Small carbon deposits filling the surface depressions lower the pushing load. In contrast, excess carbon growth creating a protrusion shape occasionally behaves as a resisting force during pushing. This study is performed to elucidate the influence of the carbon-covered area on the pushing load. Chamber wall images were gathered at operating coke plants by means of an inspection apparatus, which was inserted into the high-temperature chambers. An image processing technique was devised for classifying the wall surface into three states: bare brick, dense carbon, and patchy carbon. It was confirmed that the dense carbon has the optimum amount for suppressing high pushing loads. Statistical analysis using a probability model demonstrated that stable pushing can be obtained in specific dense and patchy carbon amounts.