Experimental Study On Coarse Coal Slimes Efficient Separation In Three Products Liquid-solid Fluidized Bed

For the issues occurred in the application of traditional TBS such as ash content of overflow slightly high, underflow with large amount of coal,effective sorting grade narrow, separation effect poor for difficultly washed coarse coal slimes, wide graded and difficultly washed coarse coal slimes separation theory is discussed in detail from theory of particle sedimentation principle and suspension layered. Design new three products TBS with inner and outer chambers and establish a complete closed laboratorial separation system. Three products TBS based on the method of roughing and select, separates coarse particle materials with high density in advance, effectively reduces the amount of clean coal in underflow, improves coarse coal slimes density and particle size composition, weakens the granularity to the effect of density separation, produces the three products at the same time, accord with the requirement of coal fine-separation. It has great significance to the evolution of coarse coal slimes separation technology.First, paper evaluates process effect of hydrocyclone, conducts single factor experiment of three products TBS inner and outer chamber respectively. research the discipline of Sorting results in different density set values and rising water velocities. Under the condition of the optimal sorting, grain size distribution characteristic and the separation effect of different grades are studied in the process of three products TBS separation, then optimization research on feeding coal of three products TBS is conducted, results show that: hydrocyclone actual grading granularity is 0.3mm, average distribution error, PEm is 1.75, actual classification efficiency is 63.67%. In a certain range, the separation separation density of inner and outer chamber uniformly is increased with the incearse of density set value and rising water velocity. If density set value is too large, or rising water velocity is too high, separation effect will become worse. With the increase of density value, and the outer chamber E value reduces to some extent, but not much variation;Along with the rising of the water speed, outer chamber E value increases gradually, and E value is higher than single factor separation results under condition of density set value as a whole. Density value effect is higher than water speed in the process of roughing of inner chamber;For outer chamber overflow ash content, the importance of rising water speed is higher than density value, and for number combustible recovery rate and efficiency, the importance of density value is higher than rising water speed; When inner chamber density value is 1.54g/cm3, rising water speed is 11.00mm/s, outer chamber density value is 1.28g/cm3,rising water speed is 6.00mm/s, ash content of coal gangue is 64.94%, yield is 22.53%, ash content of middings is 34.13%, yield is 33.37%, ash content of +0.25 mm clean coal is 9.91%, yield is 37.57%. TBS still doesn’t have effective separation effect to 0.125 mm high ash content slimes.In inner chamber, actual separation densities of 2-1mm, 1-0.5mm,-0.5mm respectively are 1.59g/cm3, 1.79g/cm3 and >2.20g/cm3, separation effect of coarse fraction slimes is the best at the same time. In outer chamber, actual separation densities of 2-1mm, 1-0.5mm,-0.5mm respectively are 1.38g/cm3, 1.42g/cm3 and 1.68g/cm3,corresponding E values are 0.05, 0.06, 0.20 respectively.The biggest processing capacity of TBS reaches to 25t/(h·m2), and increases about 25% than traditional TBS.Finally, the coarse coal slimes of Huipodi separation experiments are carried. when getting close to the plant ash, clean coal yield is increased by 6.47%, and the value of E lower, 0.07, showing that three products TBS has better adaptability to different coal quality.In summary, new three products TBS has good separation effect for wide fraction, high ash and difficultly washed coarse coal slimes. It can not only get low ash clean coal, also can guarantee the clean coal recovery rate and higher sorting accuracy than traditional TBS. The paper hopes to have a certain reference value to the liquid-solid fluidized bed separation theory and equipment development.