The Distribution Rule Of Mercury In Coal During The Separation Process Of Air Dense Medium Fluidized Bed

Coal occupies thirty perception in the world’s energy consumption. However, the inefficient and unclean use of coal caused serious environmental pollution. More attention was paid to coal-fired mercury pollution because several of severe mercury poisoning. There is extremely environmental importance and actual application value on the control technology of coal-fired mercury pollution. The occurrence of mercury in coal have difficulty in research because the characteristic of high volatility and low content. In the mean time, the control technology of coal fired mercury pollution research make slow progress. The control technologies are including removal before combustion, during combustion and after combustion. Coal separation technology, which is the representative of the removal before combustion, is a low-cost and mature method for it. Compared to wet separation techniques, ADMFB can avoid secondary pollution of slime water. It has a unique advantage in the control of mercury pollution. It is necessary to study the distribution rules of mercury in coal during the separation precess of ADMFB.Combine the data of screening and sink-float with mercury content,the density and size distribution model of mercury in coal is established. A detailed analysis of distribution rules of mercury in coal is builded. The model reveals a good affinity characteristics between mercury and mine mineral. Variety of testing methods such as XRD, XRF, SEM-EDX had been used to find the mineral which show a high affinity characteristic with mercury in coal. By this way, the occurrence of mercury in Guizhou high mercury content coal was studied.The affect of gas velocity, static bed height, separation quantity and separation time were studied by univariate factor experiment. The experiment results show, in the selected range of gas velocity, static bed height, separation quantity, the mercury content of cleaned coal decrease at first and then increase, the effect is significant. And the separation time have a marginal effect on mercury content of cleaned coal. A three factors and three levels orthogonal experiment was designed by Box- Behnken method of Design-Expert software. The results show that: the impact of three factors were: static bed height(B)> feed volume(C)> fluidization number(A), but the interactional effect between the factors were: BC> AB> AC. Optimized the test factor on this basis. The-25 + 13 mm,-13 + 6mm,-6 + 1mm Guizhou coal separation experiment were tested on the optimized conditions. The results show more than 50% mercury content distributed into the tail coal during the separation process of ADMFB. It can reach as high as 90.19%, the sorting possible deviation E is 0.06 g/m3.