Study on subsection filtration for coal slurry based on regulation ofpore structure of filter cake

In order to solve the problem of slow velocity of filtration,high moisture of filter cake and filter cake unloaded difficultly,the process of subsection filtration for coal slurry was proposed based on the regulation of pore structure of filter cake.Using coal slurry filtration device and pore measurement device for filter cake,the effect of subsection filtration for coal slurry on filter cake moisture,formation time for filter cake,dehydration rate and pore structure of filter cake were studied.The results show that compared with hybrid filtration for coal slurry,the moisture of filter cake is lower,the formation time is shorter,and the dehydration rate is larger.With the increase of -0.074 mm particles content,the effect of subsection filtration for coal slurry on filter cake moisture,formation time and dehydration rate increases rapidly,reaches the maximum and then decreases.When -0.074 mm particles content is between 20%～40%,the subsection filtration for coal slurry has the most remarkable effect.Essentially,the subsection filtration for coal slurry reduces the filling of -0.074 mm particles to large pores,with the result that the content of pores with size less than 4 μm is little change,the content of pores with size 4～50 μm is significantly reduced,the content of pores with size larger than 50 μm is obviously increased,and the porosity of filter cake for coal slime is larger.