Development of energy saving technology of coke dry quenching

Abstract

Application of coke dry quenching technology provides saving of energy resources, decreasing of environment pollution and increase of metallurgical coke quality. Despite of advantages of coke dry quenching facilities, an additional quantity of circulating gas is generated because of quenching technology peculiarities. This additional circulating gas must be released out of the cooling agent circuit resulting in environment pollution. Existing and proposed methods of reduction of emissions into atmosphere of excess circulating gas considered. It was shown, that utilization of the excess circulating gas as a fuel is the most effective solution of the considered problem. The solution comprise stabilization and support of combustible components composition in the circulating gas at the level of approved indices, joining of excess gas flows out of the dry quenching facility chambers, it enrichment by some amount of high calorie gas (coke or natural) and supply to gas uses. This technical solution was first realized by ArcelorMittal at the coke plant of the steel-works after E. Zendzimir in Krakov, Poland. In 2017 at the EVRAZ NTMK coke plant a project of the dry coke quenching facility modification was realized, comprising utilization of excess circulating gas, which has a considerable technical difference comparing with ArcelorMittal project. According to technology flowsheet, the excess circulating gas is collected  out of operating chambers into a collector, cleaned of dust in a bag filter, chilled, enriched by a high calorie gas and delivered into the gas pipe of BF gas for further utilization as a fuel. To increase efficiency of the technology and to reduce the natural gas consumption for calorie content of enriched gas stabilization and supply it into the BF gas pipe line, the CO and H2 content in the circulating gas of the coke dry quenching facility is kept at the level of 12–15 and 4–5 % correspondently. Implementation of the technical modification of the coke dry quenching facility with elimination of harmful substances emissions within the excess circulating gas provided decrease of harmful substances emissions at JSC EVRAZ NTMK – 4 kg per ton of steel.