The Design And Implementation Of Temperature Control Of Pellet Roasting Machine

Large-scale belt-type pellet roasting machine is widely used in foreign countries,with the features of high efficiency,stable,high-quality,energy-saving and environmental protection.But in China,the pellet production line is too backward and small.Therefore,it has a very important significance to study and develop large-scale belt-type pellet roasting production line.In pellet production process,preheating and roasting are two key procedures for the physical property and chemistry analysis of pellet.Suitable and stable temperature control in preheating and roasting can guarantee the quality of the pellet directly.Based on Shougang Jingtang united iron&steel company's 4 million tons belt-type pellet roasting production line,choosing the temperature of roasting system as research object,this paper present a new temperature control scheme,design a temperature cascade control system for roasting machine,and a quick,accurate and stable temperature regulation of roasting machine is realized.The main contents are summarized as follows:(1)Introduces the important significance and necessity of research and develop large-scale belt-type pellet roasting production line,briefly summarizes the characteristics of belt-type pellet roasting machine,analyzes the development of temperature control technology,illustrates the great inertia,time delay and big interference characteristics of roasting machine.(2)Introduces the process flow of pellet production in Shougang Jingtang united iron&steel company,emphasizes the characteristics,constitution and control of fan system,nozzle system and roasting system,expounds the features of roasting machine temperature distribution and control in detail,discussed the control strategy thought of the system.(3)Studies the basic concept,constitution,characteristics,design ideas and PID parameter adjusting method of cascade control system,illustrates the principle of cascade control system and the superiority over single-loop control system,drafts control scheme of roasting machine temperature.(4)Using Rockwell Rslogix5000,especially its PID(E)function module,the roasting machine temperature control program is completed.The major control loop is temperature control,and the auxiliary control loop is coke oven gas flow control.The control parameter is adjusted through two-step adjusting process of cascade control system.Finally,the hardware and software of roasting machine control system is finished in ControlLogix platform.This paper presents a roasting machine temperature control scheme,which realizes a quick,accurate and stable temperature regulation.Since this control system put into operation,it shows the advantages of stable,fast response and high accuracy.Now the output of pellets is 13000t/d,and the compressive strength of pellets maintains in a high level of 2700± 100N,which provide a guarantee for super size blast furnace production.