| As the nickel sulfide ore resources increasingly depleted,it has become more and more important for high efficiency and low cost of laterite nickel ore processing to meet the demand of the growth of the nickel,based on the High Pressure Acid Leaching(High Pressure Acid Leaching,abbreviated HPAL)process of laterite nickel ore wet smelting technology is more and more attention,it also become the main trend for the future development of nickel smelting process.High pressure acid leaching is the core technology in wet smelting process,and the multistage pulp preheater is one of the key links,its process parameter stability directly affects the subsequent production process quality and safety.But the high pressure acid leaching multistage pulp preheating process itself with multi-variable,strong coupling,change features,nonlinear,various interference factors,etc,and materials are closely intertwined.In an actual pulp preheating process,we mainly adopts the conventional PID control method,but when the production load adjustment,all levels of preheater liquid level fluctuation is severe,the control method effect is poor,it is difficult to guarantee load at the same time of stationarity and material of(level).This thesis is set in a nickel cobalt smelter project,in view of the present control system for high pressure acid leaching,they didn’t take the multistage preheater and autoclave as a material balance as a whole,and without a unified coordination mechanism of load control,appeared to ensure the continuous stable production load,has triggered a preheater liquid level fluctuation phenomena at all levels,this paper proposes a method of multistage preheaters load-level coordination control.The details are as follows:(1)Summarizes the pulp preheating process control and modeling of the development process of the present situation,analyzes the characteristics of pulp preheating process,and the difficulties of the control,as well as the practical problems in the production of pulp preheating control method,and put forward the whole pulp preheating process as the mind of a material balance as a whole.(2)Multistage preheaters uniform control method and load-level coordination control method are studied,illustrating the idea of load-level coordination control method,and the characteristics of this kind of control method is to use the full load the main benchmark setter load level and to achieve the coordination control.On this basis,the architecture of the multistage preheaters load-level coordinated control system is designed,and the load-level coordinated controller of multistage pulp preheating process is developed.(3)The high pressure acid leaching process of multistage preheater control system simulation platform is developed,the experiment platform make use of METSIM process simulation software to establish the flashing model of high pressure acid leaching process,the flashing steams go into Matlab by DDE,combined with Matlab to complete the dynamic model of level in pulp preheating process.In addition,this experiment platform designs and develops the monitoring interface of multistage pulp preheating process in high pressure acid leaching by use of the HMI Display Builder software.(4)finished the multistage preheaters uniform control method and load-level coordination control method simulation experiment in multistage preheaters of high pressure acid leaching process simulation experiment platform,through the comparison,shows that the load-level coordination control control strategy can achieve better control effect. |
