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...

Metallurgical coke

Metallurgical coke Metallurgical coke or Met coke in short is a hard carbon material produced in the process of the “destructive distillation” of various blends of bituminous coal. It is produced by carbonization of coal at high temperatures (1100°C) in an oxygen deficient atmosphere in a coke oven. A good quality coke is generally made from carbonization of good quality coking coals. Coking coals are defined as those coals that on carbonization pass through softening, swelling, and re-solidification to coke. One important consideration in selecting a coal blend is that it should not exert a high coke oven wall pressure and should contract sufficiently to allow the coke to be pushed from the oven. The properties of coke and coke oven pushing performance are influenced by following coal quality and battery operating variables: rank of coal, petrographic, chemical and rheologic characteristics of coal, particle size, moisture content, bulk density, weathering of coal, coking temperature and coking rate, soaking time, quenching practice, and coke handling. Coke quality variability is low if all these factors are controlled. The coal-to-coke transformation takes place as follows: The heat is transferred from the heated brick walls into the coal charge. From about 375°C to 475°C, the coal decomposes to form plastic layers near each wall. At about 475°C to 600°C, there is a marked evolution of tar, and aromatic hydrocarbon compounds, followed by re-solidification of the plastic mass into semi-coke. At 600°C to 1100°C, the coke stabilization phase begins. This is characterized by contraction of coke mass, structural development of coke and final hydrogen evolution. During the plastic stage, the plastic layers move from each wall towards the center of the oven trapping the liberated gas and creating in gas pressure build up which is transferred to the heating...