Research On Gun Position Control And Gun Life Of Ausmelt Furnace Gun

The research object of this thesis is the Ausmelt furnace nickel smelting lance. Due to the short service life which was about60h, the techniques for extending span life of the lance was researched in this paper. The depth of lance immersing in molten pool is one of critical factor to influence the lance lifespan. The state of lance during the churning process is used to estimate depending on the experience of operations personnel. However, this may led to low accuracy of locating lance position, instability, short service life, and it is difficult to reach the required production target.This thesis mainly study how to improve lance automatic control technology to perfectly control lance insertion depth when it immerge into molten pool. On this basis, this thesis study how to improve service life of Ausmelt lance. The research includes the following six subjects:(1)The study of nickel smelting lance back pressure relationship with lance insertion depth;(2)Design and renovation of lance end pressure detection system;(3)Theoretical derivation of lance end pressure and back pressure parameters;(4)Optimization end pressure and back pressure parameters in combination with production practice;(5)The establishment of lance end pressure mathematical model to control lance position;(6)Study of factors affecting lance lifespan such as lance burning speed, lance material, Ausmelt furnace material quality, bendy outer air spool pipe and so on.In the aspect of theoretical research on the variation of lance back pressure and lance end pressure relationship with lance insertion depth, two conclusions are obtained that back pressure is logical theory relation with end pressure as well as back pressure is positive linear relationship with static energy by back pressure and the gas total pressure equations. With the increment of lance insertion depth, the reaction force of melt to lance airflow increases. In order to overcome the reaction force and to fulfill process requirements, both lance end pressure and lance back pressure need to be increased. The theoretical values for end and back pressure parameters are determined which are combined with fluid mechanics and pipe resistance knowledge. End pressure set value is between13to22kPa and back pressure set value is between 74to109kPa. Meanwhile these set values are optimized through date statistical analysis. In the aspect of design and renovation of lance end pressure detection system, based on the design principles of pressure pipe, diameter of pressure pipe is determined; meanwhile lance end pressure detection system is set and it can be used to control lance insertion depth, the automatic control technology of lance position is promoted. After transformation, the average lifespan of lance rose to91hours. In the aspect of lance end pressure mathematical model to control lance position, more than2000sets of date are collected. On the basis of end pressure subsection principle (8-18kPa and18-30kPa) and combined with slag analysis which is one of the factors affecting lance insertion depth. The reasonable mathematical model is established which provide reliable operation and theoretical basis for lance insertion depth automatic control. The burning speed is fastest when lance run between20to65hours. In order to decrease burning speed of lance, the paper proposed experimental study by this stage.