Research On The Technology Of Eliminating The White Plume Of Steel Plant

The flue gas generated in the sintering process of the steel plant is directly discharged from the chimney after wet desulfurization,resulting in serious white plume.Such white plume not only pollute the environment around the steel plants,but also create conditions for the formation of haze weather.In order to solve the environmental problems caused by white plume,Shanghai and other places have issued relevant policies in recent years to put forward governance requirements.It can be predicted that in the increasingly stringent environmental requirements,the elimination of white plume is the trend.However,the existing research has not been sufficiently in-depth analysis of the influencing factors of white plume,and the general enthalpy and humidity chart analysis cannot take into account the influence of diffusion factors and obtain accurate control parameters of elimination technology.And there is no design method for eliminating technology.Therefore,it is very necessary to carry out research on eliminating.Firstly,the generation and dissipation mechanism of white plume was analyzed from the enthalpy and humidity chart,and the critical boundary equation of eliminating white plume in winter and summer was obtained by theoretical calculation.However,the influence of diffusion factors could not be taken into account in the enthalpy and humidity chart.The CFD simulation method was proposed to deeply study the influence of environmental wind speed,smoke exhaust velocity and chimney height and other diffusion factors on the generation and dissipation mechanism of white plume.By simulating the flue gas conditions on the threshold,it is found that white plume still exist in practice,which verifies the importance of diffusion factors for the appearance of white plume.Secondly,the diffusion characteristics of white plume under different ambient temperature,ambient relative humidity,ambient wind speed and smoke exhaust velocity were simulated and analyzed.The results show that the influence of temperature and humidity,smoke exhaust velocity and wind speed on the diffusion characteristics of white plume is significant.Then,the distribution differences of white plume under typical working conditions in different seasons we re analyzed,and the order of severity of white plumes was obtained as follows: winter>spring≈ autumn> summer.After that,the numerical simulation study was carried out on the flue gas heating technology,the flue gas condensation dehumidification technology and the condensing heating composite technology.On the basis of considering the diffusion factors,the more accurate control parameters and the dissipation law of white plume under different technologies were obtained.The calculation results show that the heating technology,considering the diffusion factor of heating temperature than that without considering the diffusion factor of heating temperature is 23℃;Using the condensation dehumidification technology,the flue gas dehumidification temperature considering the diffusion factor is 1.06℃ higher than the dehumidification temperature without considering the diffusion factor,and the dehumidification temperature of 20℃ is the ideal dehumidification threshold.Using the condensing and reheating technology,the reheating temperature of the completely eliminated white plume is reduced by the quadratic function with the decrease of the flue gas saturation temperature.Compared with the calculated value without considering the diffusion factor,it is found that the influence of the diffusion factor on the reheat temperature of flue gas increases with the increase of the saturation temperature of flue gas.Finally,the design of three white plume elimination retrofit schemes was carried out for a steel plant using the control parameters taking into account the diffusion factors.In this paper,the design methods of different white plume elimination technologies are given,and the key thermal parameters of each scheme are calculated in detail.