Experiment Of East Mongolia Lignite Drying Characteristics And Numerical Simulation Of COMBDRY Low-Temperature Gas Drying Process

The lignite resources are rich in C hina, but the moisture content of lignite is high, and lignite drying is an important process to achieve effic ient and clean utilization of lignite resources. COMBDRY low temperature gas drying technology has the characteristics of simple structure, simp le operation and low energy consumption. In this paper, the drying characteristics of the lignite were studied on the Huolinhe lignite of East Mongolia. Using FLUEN T software to simulate lignite drying process of COMBDRY low-temperature gas drying technology, which has a great significance to understand the drying princ iple and optimal drying parameters deeply and to achieve large-scale equipment of COMBDRY low- temperature gas drying technology.In this paper, according to the drying characteristics of the East Mongolia lignite, the influence of temperature and drying medium on the drying characteristics of the horizontal tube furnace was studied. The peak area ratio of the related groups was obtained by the peak area ratio of the related groups, and the influence of the temperature and the drying medium on the oxygen functional groups on the surface of lignite was obtained.The influence of the mass of the coal sample on the drying characteristics is mainly reflected in the growth of the drying time. Temperature has a significant influence on the drying characteristics of lignite. The higher the temperature is, the more rapidly the moisture content of dry base decreases, the shorter the drying time is, the greater the drying rate is. Under the different temperature, the drying process of the coal sample generally experienced three stages, inc luding the accelerating drying stage, constant speed drying stage and falling speed drying stage. With the increase of drying temperature, the range of accelerating drying stage is expanding, but range of constant speed drying stage becomes smaller. When the water content is less than 0.3, the coal sample enters the stage of falling speed drying. At the same temperature, the effect of different drying media on the drying rate is not significant, which is mainly related to the physical properties of the drying medium.In air atmosphere, the ratio of COO H/Car increases with the increase of temperature, and the ratio of C H3/C H2 is increased. It shows that the drying process causes the formation of carboxy l groups in the formation of methylene oxide. And with the increase of temperature, the degree of oxidation will continue to deepen. And after 200 degrees, the increasing trend becomes smooth and even decreases. It indicates that the carboxyl group will be decomposed, and the rate of the oxidation of the carboxyl group is less than the rate of the carboxyl group after 200 degrees. In the inert atmosphere, lignite is not prone to oxidation, and the oxygen containing functional groups only occur in a small amount of decomposition. But in the aerobic environment, lignite is prone to oxidation. With the increase of the oxygen concentration in the drying medium, more obvious the oxidation is and more easily aliphatic oxidized.The simulation of COMBDRY low temper ature flue gas drying was simulated according to the experimental condit ions. Then the corresponding data and simulation test conditions obtained are compared and analyzed. Through analyzing of the temperature change of the height of the test and the simulation of the dryer, the pressure difference between the flue gas inlet and outlet, and the removal of moisture from lignite before and after drying, it shows that the simulation method can describe the drying process well.The effect of different inlet temperature and bituminous coals on the process of COMBDRY low-temperature gas lignite drying were studied in this simulation. It shows that: with the increase of gas temperature at the entrance, the temperature and velocity of the flue gas arriving at the outlet decreased more; In the height direction of dryer, the increasing trend of water vapor mass fraction is more obvious; the water in the evaporation of lignite particles is also more, and the drying effect is better. Inlet temperature increased from 120 degrees to 200 degrees, and the moisture removal rate increased from 5.9% to 10.8%. Also with the increase of the ratio of bituminous coal, flue gas temperature along the height direction of the dryer is higher; Flue gas flow rate in the drying process red uces the more; The static pressure difference between the inlet and outlet of flue gas increases gradually; The more water is removed by the lignite particles, the better the drying effect is. The ratio of bituminous coal increased from 4 to 10, and the moisture removal rate increased from 7.3% to 21.1%.