Control And Realization Of Activated Carbon Desulfurization System In Sintering Plant

Iron and steel industry is another polluting industry after thermal power industry,a large number of pollutants such as sulfur dioxide?SO₂?,nitrogen oxide?NO_X?and dusts particulate matter are produced in the process of steel smelting.At present,the problem of desulfurization in China's iron and steel industry has become a very urgent practical problem due to the aggravation of environmental pollution caused by sulfur dioxide and its derivatives PM2.5.In this paper,taking the practical engineering project of a steel company's sintering plant as the research object,a new flue gas desulfurization system was designed on the basis of integrated research on activated carbon desulfurization technology.Firstly,the overall scheme of activated carbon dry desulfurization system was introduced detailedly from the aspects of desulfurization principle,technological process flow,control logic and factors affecting desulfurization efficiency.Moreover,the essential parameters of sintering machine and desulfurization system were given.Secondly,the hardware and software parts of the desulfurization system were designed synthetically.The distribution of I/O points and the selection of PLC,analog module,touch screen,host computer,frequency converter,pressure gauge,thermometer,flow meter and material level-sensing meter were introduced exhaustively based on the fully understanding of the principle and requirement of activated carbon dry desulfurization control system,and the working principle,construction strategy and parameter index of the hardware system were clarified.The flue gas desulfurization system control strategy based on Rockwell 1756 series PLC and its connection method with configuration network were elaborated in software design part,and the flow chart of related programs and the configuration screen of the host computer were given.The specific part of the program was presented as an appendix.Furthermore,in order to ensure the stable operation of the desulfurization system,a dual CPU redundancy system was also designed in this paper.Finally,the automatic control strategies of main subsystem were designed and analyzed concretely.A temperature control method of activated carbon in the material circulation system was given specially and a series of improvement measures of the activated carbon temperature control,the gas chamber barrier leakage,the regeneration tower system,the sulfuric acid system and the flue gas system were proposed in the subsequent debugging operation stage.It has been proved by field practice that the activated carbon desulfurization system designed in this paper meets the production requirements of the practical sintering system,and the SO₂ emission concentration of flue gas after desulfurization is only 55 mg/Nm³,which is far lower than the national emission standard.