Study On Operating Characteristics And Rotary Distillation Experimental System With Oil Shale And Solid Heat Carrier

With the development of the human society and economy, the contradiction between supply and demand on energy resources become more and more severe, for the global demand for energy keeps growing, while the mineral energy resources are increasingly exhausted. Oil shale resource with its abundant reserves is an important supplement of the fossil resources which are represented by oil and gas. Vigorous developing of oil shale industry can not only maintain global energy supplies, but also relates to the major concern of the developing countries which don’t have enough crude oil, the national economic development and energy security. Although the development of oil shale resources has a long history, but because of the lean ore, the expensive exploiting cost and severe environmental contamination, the large-scale development and utilization has been a bust.In the thesis, we self-design and build the oil shale and heat carrier rotary distillation experimental system, detailed studied temperature measurement of rotary equipment, particle motion process in retort and heat transfer between solid heat carrier and oil shale. The results show that it is feasible that using wireless temperature measuring devices for rotary retort. The conclusion that using rotary retort is beneficial to improve oil yield efficient is further verified, by studying the basic features of oil shale which is mined in Huadian and analyzing the reasons which caused different oil yield between aluminum retort method and the self-designed rotary retort.1. On the platform of rotary retort in which the right angle stirring plate is internal installed, under different retort inclination and rotate speed, the mean residence time of mixture has been researched that is influenced by the particle proportion of the mixture consisting of oil shale particle and solid heat carriers (ash) and by the retort rotation direction. The different retort rotation direction can make differnet work pattern of stirring plate, and the mean residence time of mixture will be longer when ash has a greater proportion and the stirring plate works at right angle pattern.2. The physics model of particle mean residence time has been deduced by particulate trajectory model which is derived from granular dynamics theory. The results from this model relatively agree with measured particle mean residence time data, and the mean prediction error is less than15%. But the model is not sufficient when it works at high rotate speed, large retort inclination and high filling rate.3. Theoretically based on discrete element method, when retort rotate speed is10r/min, rotation is anti-clockwise (work at right angle stirring plate), filling rate is 30%, and retort inclinations are2.16°,3.24°,4.33°respectively, the three particle mean residence times have been simulated. The results show that:the lift and drop trajectory of particles in retort is similar to parabola; at different retort inclination, the particle mean residence time is in accord with normal distribution; and simulation and experiment results show a good consistency.4. Motion track simulation of single particle and granular flow shows that impact between particles will cause particles deviation, dispersion and off-track. When at the same rotary speed, the change of filling rate is of no significant effect on motion track of particles. When at the same filling rate, particles has higher horizontal speed as the rotary speed increase, meanwhile, due to the impact of the right angle stirring plate, particles are not have farther lateral displacement. To the granular flow, when the filling rate is lower, the impact of the right angle stirring plate is more obvious, there are more particles dropped on the retort floor. But when the filling rate is higher, most of the particles are moving by rolling and slipping. When the rotary speed increases, discharge rate of particles on stirring plate is significantly raised, and get the particle’s lateral speed faster.5. The influence of rotate speed and filling rate on the heat transfer time of mixing oil shale and solid heat carrier and temperature distribution uniformity among particles has been conducted. At a fixed filling rate, the heat transfer time needed to reach500℃increases in accord with the increase of rotate speed. They are in linear related. At a fixed rotate speed, the needed heat transfer time decreases with the increase of filling rate. The mean temperature of oil shale particle changes fast at the beginning of heat transfer; and then change slowly when the temperature diffirence between oil shale and ash is decreasing. At a lower filling rate, the increase of rotate speed is benefit to particle mixing, decrease temperture difference, and get more heat transfer uniformity. But if the filling rate is higher, the increase of rotate speed can not improve uniformity obviously. At a fixed rotate speed, the temperature variance descreases according to filling rate, and then the oil shale heat evenly.6. The shale ash being served as solid heat carrier, the distillation experiments have been implemented by the rotary retort on2kinds of oil shale particles which have different size distribution. Based on the quantitve evaluation of the oil yield, the influence of certain factors on distillation process has been studied. When the size distribution is0-3mm, the mix proportion of oil shale and solid heat carrier is1:4, the initial temperature of solid heat carrier is750℃and the rotate speed is19r/min, the oil yielding rate can achieve95.02%. The oil yielding rate increases in accord with rotate speed, but decreases obviously when the rotate speed ω>19r/min. The rotate speed that is either too fast or too slow will adversely affect the heat transfer between oil shale and solid heat carrier, thus will decrease oil yielding rate. A higher initial temperature of solid heat carrier is benefit to oil yielding rate, but a too high initial temperature of solid heat carrier will cause shale oil vapour secondary pyrogenation in the high-temperature region, therefore, decrease oil yielding rate. The best economical efficiency can be achieved when the mix proportion is1:4. If the solid heat carrier is in less proportion, it may not supply enough heat, and if in too much proportion, it will cause heat waste and decrease in the capacity of oil shale processing. Small-sized oil shale particle has larger surface area, so it is beneficial to heat transfer, thus will have good distillation effect.