Technologies for improvement in Coking process in Byproduct Coke Ovens Jul31

Technologies for improvement in Coking process in Byproduct Coke Ovens...

Technologies for improvement in Coking process in Byproduct Coke Ovens Coking coals are converted to coke in large byproduct coke oven batteries. The coking process consists of heating blend of crushed coking coals in the absence of air to drive off the volatile compounds. The resulting coke is a hard, but porous carbon material which is used for the reduction of iron bearing materials in a blast furnace. The byproduct coke oven also recovers volatile chemicals in the form of coke oven gas, ammonium sulphate, tars, and oils. In last three to four decades several technologies have been developed which have not only resulted into vast improvements in the process of coking in the byproduct coke oven batteries but also have improved the quality of produced metallurgical coke. Majors of these technologies are given below. Selective crushing of coals This technology is a theoretically sound technology and aims at controlling the degree of crushing of the different constituents of coal.  It aims to improve homogeneity of reactive and inert components in coal. The reactive components of coals are primarily vitrinites and are the softest constituents while the mineral matters of coals are the hardest components. In conventional coal crushing units, the vitrinites get crushed to a relatively finer size compared to mineral matter constituents when the entire coal is crushed together. For producing coke of higher quality, it is desirable to crush the mineral matter finer than the vitrinite component of the coal so that during the process of coking, when the coal charge softens, the mineral matter is assimilated better, leading to the improved strength. This is usually carried out by crushing of coals in two stages. This technology is helpful when coals are petrographically heterogeneous. Coal moisture control Coal moisture control uses...

Dry Cooling of Coke Apr25

Dry Cooling of Coke

Dry Cooling of Coke Dry cooling of coke is known as coke dry quenching (CDQ) and is an alternative to the traditional wet quenching.  During wet quenching of run of oven coke, sensible heat of the hot coke is dissipated into the atmosphere and is lost. In addition there are air borne emissions (0.5 ton of steam per ton of coke laden with phenol, cyanide, sulfide and dust) and a large quantity of water (around 0.6 Cu m per ton of coke) is needed for wet quenching. The contaminants in water are also discharged in the environment. In a Coke Dry Cooling Plant (CDCP) red hot coke is cooled by inert gases. The heat energy from the red hot coke is recovered in a waste heat boiler for use as steam, resulting in energy conservation as well as a reduction in coke particle emissions.  Around 80 % of sensible heat is recovered. The CDCP process flow is in Fig 1. Fig 1 Process flow in CDCP History After pilot and pilot/commercial trials the first full scale CDCP installation was commissioned in 1965 at the Cherepovets Iron and Steel Works in then USSR. By 1978 around 50 CDCP modules of 56 tons per hour were in operation in then USSR. Japan purchased license from USSR and three Japanese installations were commissioned in 1976 – 77. In India MECON purchased license for Giprokoks design CDCP from USSR and the first 12 chambers were installed at Visakhapatnam Steel Plant. The first CDCP plant was commissioned in September 1989. Presently 19 chambers of this design are in operation. Concept of Coke Dry Cooling Hot coke is brought from the battery to the CDCP in bottom opening bucket kept on the quenching car. This bucket is lifted at the...