Advances in the reduction of emissions from coke quenching

Pursuant to the German Clean Air Directive (TA Luft) low-emission technique s must be used for the cooling of the coke during the coking process of har d coal. This requirement can be fulfilled by both wet and dry quenching pro cesses, according to a draft of a the European Commission for the descripti on of the Best Available Techniques (BAT) [1]. Most of the coking plants op erated worldwide use the wet quenching process. This process cools down the coke after having been pushed out of the coking chamber at approx. 1100 de grees C by means of water in a process lasting less than three minutes. [2; 3]. With both processes, emissions are unavoidable. The main components of the emissions resulting from wet quenching are dust, carbon monoxide (CO) and hydrogen sulphide (H2S). Calls for more intensive use of dry quenching processes go back to the time when dust emissions of 50 - 100 g/t coke were still usual for wet quenching. The advances that have been made in the mea ntime in the reduction of emissions arising from the wet quenching process have so far been more or less unnoticed. The following article will deal pr ecisely with these advances. The efficiency of a modern coke wet quenching process in terms of emission reduction is not only due to emission reducing measures adopted in the actu al quenching process, but also due to the optimisation of operational and p lant engineering technologies in coke-making plants over the last few years . Improved process control achieves move uniform carbonising which has the positive effect of lower emissions during the quenching process. The optimisation and coordination of the individual measures has brought ab out a considerably improved coke wet quenching process than was state of th e art in the 1980s.