A Simulation Study On Stability And High Efficiency Of High-mixed Anthracite Coal Combustion In Predecomposition Kiln

Today, China’s energy situation is extremely serious. It is energy structure that determine the coal as the major energy in china, meanwhile the cement industry requires huge amounts of coal. Therefore, the cement rotary kiln for burning anthracite play an important role in China’s energy consumption. However, using low grade anthracite as fuel in cement production has a lot of problems, including igniting difficulty, combustion instability and low combustion efficiency. So it has great importance to research and implement the effective control of highly efficient, stable combustion in the rotary kiln coal production.To study the problem in cement kiln burning anthracite, this paper chose the cement kiln, owned by Hunan JinLei Southern Cement company limited(referred to as JinLei company), to conduct the following research by the methods of thermal test calculation, TGA experiments and numerical simulation:Firstly, the plant practise. For a month-long study and practice In JinLei company,I’m learning in the control room, production lines, laboratories and other operating post in the process of internship. In accordance with the relevant national standard I make the rotary kiln system thermal test collect related parameters and determining the energy balance. To this I laid a good foundation for the follow-up work.Next, take the ? 4.0×60 m of JinLei company’s rotary kiln as research object,using Gambit build computational geometry model, utilize Fluent establish turbulent gas-particle flows, pulverized coal particle movement, pulverized coal combustion,radiation heat transfer and other mathematic models. According to the data of the factory and thermal test determine the boundary conditions, For numerical simulation of rotary kiln and contrastive analysis with the factory test results proved the model’s reliability.Then taking the mixed coal(the ratio between anthracite and bituminous coal is4:6) used by the kiln as an initial value, the author simulated the anthracite combustion process inside the kiln model, and gradually increase the blending ratio of anthracite to investigate the primary air, coal fineness and primary air oxygen concentration’s effects on anthracite high efficient combustion. The results show that,the implementation of these programs can reduce the amount of cold air and improve coal fineness on the basis of existing facilities at the plant, and have a positive impact on the anthracite stable combustion and combustion efficiency, but can’t achieve100% anthracite combustion on the kiln.Finally, introduce the oxyfuel technology to investigate the combustion rules with the increase of anthracite blending ratio in the condition of 27% oxygen concentration. When the primary cold air quantity is 6%, the coal fineness is 80 micron over 5% and the primary oxygen concentration is 27%, the simulation results about 100% anthracite combustion on the kiln shows a better burning stability and higher combustion efficiency.