As a major coke producer, China accounts for about 60% of the production capacity of the world. The whole coking process contributes a majority of the atmospheric pollutants such as NOx, SOx, carbon granule etc. because of the combustion nature of coke gas. Recently, a new national standard named ‘Emission standard of pollutants for coking chemical industry’ was issued by the National Ministry of Environmental Protection, which stipulated anupper emission limit for NOx, SOx and so on. As the biggest coke producer in the west of China, Baofeng Energy Ltd processes 8 coke ovens and a production capacity of 5 million tons of coke every year. The concentration of NOx in tail gas of all the 8 coke ovens is between 900~1200 mg/m3, which is obvious out of the national limit (less than500 mg/m3). A technical agreement was signed between Baofeng Energy Ltd and DICP for the purchase of a proper way to remove NOx economically.
Efficient low temperature SCR catalyst, which can not only accommodate the relative low temperature (typically below 300oC), but also can resist the deactivation of SOx and coal tar, has been a hot area of research for years.Based on theoretical and practical experience, group DNL0909 developed a novel SCR catalyst with a honeycomb monolithic configuration. At 4th April 2014, an industrial pilot SCR system was commissioned and an instantoperation success was achieved at Baofeng Energy Ltd, Yinchuan, Ningxia province. This efficient SCR catalyst showed a very high and stable NOx reduction efficiency with 98~99% during 1200 hours running and the concentration of NOx in effluent maintained less than20 mg/m3.
The excellentexperimental result proved the feasibility and validity of SCR process for coke oven by using our novel monolithic catalyst. （By Hao Cheng）