Study On Particle Size Distribution Characteristics Of Filter Press Cake And Pressurized Filter Cake

With the increasing attention of the state to energy cleaning and utilization,the importance of coal processing is becoming more and more important.Because the current coal preparation technology is still dominated by wet coal preparation,the filtration of coal sludge becomes an unavoidable process in the process of coal preparation.The filtration of coal preparation plant generally belongs to filter cake filter,so the structure characteristic of filter cake is closely related to filtration effect.On the one hand,The filtering effect is affected by the pharmaceutical system,such as the type of surfactant and its dosage,filtration pressure and other factors.On the other hand,The selection of filtering methods will also affect the filtering effect.This paper carries out filtration test under different conditions.This article takes-0.045 mm Shendong long flame coal as the test sample,and the pressure filter as the dehydration equipment.It examines the influence of factors such as filtration pressure,sample particle size and filter aid on the filtration effect;the frame filter press is used for dehydration.Equipment,to investigate the influence of filtration time,filter aid type and other factors on the filtration effect.The filter aids used were mainly cationic surfactant dodecyl dimethyl benzyl ammonium chloride(1227),anionic surfactant sodium dodecylbenzene sulfonate(SDBS)and high-molecular flocculant 12 million.Non-ionic polyacrylamide(NPAM).The main indicators for evaluating the filtration effect include the filtration rate,the cake moisture,and the average mass resistivity of the filter cake.The particle size analysis of each part of the filter cake was performed using a laser particle size analyzer to study the effect of different conditions on the filtration effect.The main conclusions are as follows:In the pressure filtration,the filtration rate can be increased by increasing the filtration pressure,and the purpose of reducing the cake moisture is achieved.When the pressure increases to a certain extent,the dehydration effect tends to be stable.-0.045 mm particle size filtration is the slowest and the cake moisture is the highest,which plays a decisive role in the filtration effect.In the process of pressure filtration,when using a 200 mesh nylon monofilament filter cloth,the clogging of the filter cloth is mainly blocked by-75 ?m particle size,and then the clogging effect of irregularly large particles of 75-210 ?m on the filter cloth is gradually increased.The proportion of-75 ?m grains gradually decreases and gradually increases in the pores.In the pressure filtration process of the frame,the filtration pressure is gradually transferred from the feed end to the entire filter cake.The proper lengthening of the filter press time helps to reduce cake moisture.In the process of pressure filtration,coarse particles are mainly concentrated at the bottom of the filter cake,and then tend to be evenly distributed.12 million NPAM as a filter aid helps increase the filtration rate during pressure filtration and does not reduce cake moisture.The optimum amount is 80.0 g/t.When using plate and frame filter press,because the filtration speed is slower,the floc formed by NPAM is less likely to settle,which will cause the cake moisture to rise;SDBS will reduce the filtration rate and increase the cake moisture when used as a filter aid.The particle size is smaller than NPAM,and the moisture content of the filter cake is lower than that of the filter cake under NPAM;the best use of 1227 in pressure filtration is 580 g/t,which can significantly reduce the cake moisture,the main mechanism of action is 1227 and The extracellular polymer combines to remove moisture from the filter cake.When using plate and frame filter press,due to the long filtration time,the combination of 1227 and extracellular polymer can not discharge the filter cake as soon as possible,and agglomeration phenomenon occurs in the filter chamber and remains in the filter cake,resulting in increased water content of the filter cake.The aggregate size is about 100 ?m.