Study On The Effect Of Vibration On Lignite Dewatering And Briquetting By Mechanical Thermal Expression Process

As lignite occupies 13% of the reserves of coal resource, but its high water content limit its large-scale production and use, so it is not conducive to long-distance transport and storage. In this paper, it used self-developed equipment for lignite Vibration Mechanical Thermal Expression(VMTE), realized the integration of drying and forming to avoid serious dust pollution, reabsorption and spontaneous combustion. It mainly selected a higher water content of Zhaotong lignite, Mengdong and Xiaolongtan, which two additional lignite as a reference comparison. According to the change of lignite dewatering quality and internal structure before and after, it investigate the effects of temperature, molding pressure, vibration strength, vibration frequency, vibration time and the content of the material during dewatering on the physical structure and quality of lignite. It use a variety of detection equipment such as Mercury, infrared spectroscopy, surface tension and scanning electron microscope to analyze the changes in the characteristics of lignite from the microscopic point of view forces and dynamics perspective, and explore lignite vibration dewatering upgrading mechanism.The effect of temperature, mechanical pressure and vibration on Zhaotong, Xiaolongtan and Mengdong lignite dewatering during VMTE process was studied and compared, the effect of VMTE process on coal properties was analyzed. Research showed that temperature greatly affected dewatering molding: as the temperature increased, all three lignite moisture were reduced, three lignite dewatering effect was Zhaotong> Xiaolongtan> Mengdong; Different temperatures drop briquette strength resulted that Zhaotong lignite was more than 90%; at 10 MPa pressure or less, the pressure can promote the water removal; Pressure slightly increased the briquette mechanical strength with pressure increasing trend; the vibration strength first increased then decreased the mechanical strength; vibration frequency can slightly promote lignite water removal; the influence of vibration frequency on the mechanical strength is first increased then declined; the more vibration time was in favor of coal moisture removal within a certain range of time; the more the amount of material, the more difficult to mold.Coal Properties have a certain impact on the molding:the size of the order, which three kinds of lignite total humic acid content is in line with the free humic acid content, free coal humic acid and compressive strength was positively correlated; some functional group absorption peak intensity of the coal after dewatering becomes higher, hydroxyl and carboxyl promoted lignite molding. Coal structural change after VMTE process: coal structural change wettability changes are mainly related to temperature; small changes in the overall structure of lignite between different temperature conditions occurred; surface morphology were shown a structural irregularity, a serious block, minerals and coal small particles attached to the surface, and because of different water content display to differentiate; smoothness associated with coal water content, the less the moisture content of coal samples after treatment, the higher the smoothness, the more rules closely aligned; vibration force has little influence on coal average aperture distribution and its surface area; Finally, it explores the impact of vibration on the dewatering forming mechanism established by the change in kinetic equation from the vibration rate of dewatering to obtained:vibration function and pressure generated linkage effects, both compounding effect prompted further remove moisture, made the coal further compaction and consolidation..