Study On The Superheated Steam Drying Characteristics And The Moisture Control Technology Of Choking Coal

As a pre-treating technology in the coking process,coal moisture control technology reduces the water content of the coking coal from 12%to about 6.5%.The removal of the water can reduce the total energy consumption of coking,reduce the amount of the waste coking water,and improve the quality of the coking coal.Superheated steam drying technology has many advantages,such as high thermal efficiency,remarkable energy saving effect,safety and no explosion risk.To avoid the dust explosion risk in the existing hot air or flue gas coal moisture control technology,a new technological idea is proposed in this paper,that is,to develop a set of superheated steam coal moisture regulating device by using superheated steam as a drying medium..The main research contents and results of the paper are as following:1)Experimental research on physical properties of coking coal under the view of convection drying:The initial moisture content,thermal conductivity,thermal diffusivity and repose angle of coking coal were measured.The pyrolysis experiment and minimum fluidization velocity experiment of coking coal were carried out.The experimental results show that the coking coal moisture control can be done at a drying medium below 400 degrees.2)Experimental study on convective drying of coking coal:The drying medium is hot air and superheated steam.The experimental phenomena of coking coal convection drying were analyzed.The results showed that the moisture content of coking coal in the early stage of convective drying decreased rapidly,and the requirement of coal moisture control could be achieved soon.Several factors that may affect the drying rate of coking coal are discussed respectively during the process of convection drying.namely,the influence of the temperature of the drying medium,the thickness of the coking coal and the flow of the drying medium on the drying rate of the coking coal.A comprehensive comparison of superheated steam coal moisture control and hot air hot coal moisture control is carried out.It is found that the heat efficiency of superheated steam coal moisture control is much greater than that of hot air coal moisture control,and the drying rate of superheated steam moisture control is greater than that of hot air coal moisture control,and the superheated steam coal moisture control is more energy saving than hot air coal moisture control.In addition,superheated steam coal moisture control is safer and more reliable than hot air coal moisture control.3)Technical study on superheated steam coal moisture control of coking coal:The concept of coking coal moisture control technology of superheated steam self flow bed was put forward,and some parameters of coking coal superheated steam moisture control process were calculated.The cold test bench for small scale test of coking coal was set up,and it was found that the design of self flow bed can solve the problem of coking coal fluidity well.