Per: HENRIQUISON MAGELA BOTTREL REIS (USIMINAS), Bruno Santos Malaquias (USIMINAS), Diego Canez Fernandes (USIMINAS), Carlos Eduardo Pessoa Gomes (USIMINAS)
Abstract:
The deposit of carbon is inherent to the by-product coking process. The tendency of the carbon is to accumulate more in the oven free zone regions (roof, charging holes and also in the vertical walls) as well as in the gas ascension pipe. However, in excess deposits may cause decrease in productivity, environmental impacts and shortening of coke oven life. In this context, it was evaluated the mechanisms formation of carbon deposits , as well as the factors related to the cokemaking and coal blend. Statistical analyses were carried out to identify the main variables influencing the formation of the carbon deposits. In addition, samples of deposits collected near the charging holes and ascension pipes, as well as tar samples for determination of quinoline insoluble material (QIM) were evaluated. It was found that the material are formed by particles of pyrolytic carbon (due to gas cracking) and mainly by entrained carried particles of coal, semicoque and coke, corresponding to 60%, 54% and 72%, respectively for the regions of the charging hole, the base of the ascension pipe and upper part of the ascension pipe. Countermeasures to minimize carbon deposit formation were identified and defined, such as: free zone temperature reduction; increase of the bulk density, control of fines (< 0.105 mm), besides reducing the coal blend volatile matter and application of some decarbonization techniques.