Integrated automation system of grinding process based on intelligent optimizing control ZHAO Dayong, YUE Heng, ZHOU Ping, CHAI Tianyou (Research Center of Automation, Northeastern University, Shenyang 110004, China)
Abstract:The grinding processes in mineral processing plants are characterized by non-linearity, time-variability, with large inertia. Furthermore, their boundary conditions often change during operation, and technical indexes such as grinding particle size are difficult to measure online, and optimizing control is difficult to achieve. These often result in unstable operation, so the product quality and grinding efficiency cannot be guaranteed. This paper develops a hierarchical integrated automation system for this complex process, consisting of an intelligent optimizing process control layer and a process management layer. The structure, functions of the system and the intelligent optimizing control strategy are discussed. The intelligent optimizing process control layer includes an intelligent optimal setting system and a loop control system. Technical indexes are predicted by the soft-sensors, and the basic loop setpoints are optimized by the optimal setting models based on the prediction. This system has been successfully applied in a large mineral processing plant. The grinding processes have been stabilized, and key technical indexes have been evidently improved. Key words:grinding; integrated automation system;optimizing control 0 引言 磨礦過程是選礦廠的中間工序。礦石經過物理的研磨、fenjizuoyong,keliyoudabianxiaodaoyidingdechengdu,cainengdadaokuangshidedantijielihuojinyudantijieli,youliyuxuanbiegongxudejinshuhuishouhejinshufuji。yincimokuangguochengshiyingxiangxuankuangshengchandeguanjianhuanjie,zhijiezhiyuezhexuankuangchanpinzhilianghejinshuhuishoulv。ciwai,mokuangzuoyenenghaozhanxuankuangchangzhenggexuankuangguochengde40%~60%。因此磨礦過程實現自動控製具有重要意義。國外對磨礦過程的建模與控製的研究已經相當深入,控製方法包括優化控製[1],多變量控製[2] ,預測控製[3],但(dan)是(shi)國(guo)外(wai)的(de)磨(mo)礦(kuang)流(liu)程(cheng)和(he)設(she)備(bei)與(yu)我(wo)國(guo)不(bu)盡(jin)相(xiang)同(tong),國(guo)外(wai)一(yi)般(ban)都(dou)用(yong)棒(bang)磨(mo)機(ji)為(wei)一(yi)段(duan)開(kai)路(lu)磨(mo)礦(kuang),或(huo)以(yi)新(xin)給(gei)礦(kuang)配(pei)水(shui)力(li)旋(xuan)流(liu)器(qi)構(gou)成(cheng)磨(mo)礦(kuang)閉(bi)路(lu),並(bing)普(pu)遍(bian)使(shi)用(yong)粒(li)度(du)計(ji)等(deng)高(gao)精(jing)密(mi)在(zai)線(xian)檢(jian)測(ce)儀(yi)表(biao),因(yin)此(ci)其(qi)研(yan)究(jiu)成(cheng)果(guo)難(nan)以(yi)適(shi)用(yong)於(yu)實(shi)現(xian)我(wo)國(guo)磨(mo)礦(kuang)過(guo)程(cheng)的(de)自(zi)動(dong)控(kong)製(zhi)。國(guo)外(wai)對(dui)於(yu)磨(mo)礦(kuang)粒(li)度(du)的(de)軟(ruan)測(ce)量(liang)的(de)研(yan)究(jiu),僅(jin)限(xian)於(yu)用(yong)來(lai)代(dai)替(ti)常(chang)規(gui)儀(yi)表(biao)實(shi)現(xian)回(hui)路(lu)控(kong)製(zhi)[4]。我國的磨礦過程具有自身特點,廣泛使用螺旋分級機。磨礦過程本身的大慣性、參數時變、非線性、bianjietiaojianbodongdadengfuzatexing,yijiguanjiangongyizhibiaomokuanglidunanyizaixianceliang,daozhizaiwoguomokuangguochengzidonghuashuipingdi,muqianzhizaibufenchangkuangshixianlegeikuang、給水等基礎回路的自動控製。歐洲鋼鐵工業技術發展指南指出:“對於降低生產成本、提高產品質量、減少環境汙染和資源消耗隻能通過全流程自動控製係統的優化設計來實現[5]”。文獻[6]針對選礦過程提出了過程穩定化、過程優化、過程管理三層結構的自動化係統。文獻[7]提出了企業資源計劃(ERP)/製造執行係統(MES)/過程控製係統(PCS)三(san)層(ceng)結(jie)構(gou)的(de)金(jin)礦(kuang)企(qi)業(ye)綜(zong)合(he)自(zi)動(dong)化(hua)係(xi)統(tong),成(cheng)功(gong)應(ying)用(yong)於(yu)遼(liao)寧(ning)省(sheng)排(pai)山(shan)樓(lou)金(jin)礦(kuang),且(qie)成(cheng)效(xiao)顯(xian)著(zhu)。結(jie)合(he)磨(mo)礦(kuang)的(de)生(sheng)產(chan)技(ji)術(shu)要(yao)求(qiu)及(ji)工(gong)藝(yi)特(te)點(dian),從(cong)穩(wen)定(ding)產(chan)品(pin)質(zhi)量(liang)、提高磨礦效率、降低能耗的總體控製目標出發,基於優化關鍵生產工藝指標的實際出發,結合專家係統、案例推理等人工智能技術,提出了過程管理係統和過程控製係統組成的二層結構的磨礦過程綜合自動化係統。 1 磨礦過程描述 磨礦過程主要是將礦石經過磨礦過程,處理成細粒度級的顆粒,提供給選別作業。其工藝流程圖如圖1所示。圓筒礦倉內的粉礦經由電振排料機、給礦皮帶,送入一段球磨機內,經過球磨機、雙螺旋分級機組成的一段閉路磨礦係統細磨後,再經過細篩的篩分作用,大顆粒的礦石被送入由二段球磨機、水shui力li旋xuan流liu器qi組zu成cheng的de二er段duan閉bi路lu磨mo礦kuang係xi統tong繼ji續xu再zai磨mo,水shui力li旋xuan流liu器qi的de溢yi流liu和he經jing篩shai分fen作zuo用yong後hou的de小xiao顆ke粒li被bei送song入ru選xuan別bie工gong序xu。為wei了le保bao證zheng磨mo礦kuang分fen級ji效xiao果guo,必bi須xu在zai一yi段duan磨mo機ji入ru口kou、一段磨機出口和二段泵池處分別加入一定流量的清水。 磨礦過程最關鍵的工藝指標是二段磨礦的旋流器溢流粒度指標。從控製的角度看,影響磨礦作業的主要因素有一段球磨機給礦量、一段球磨機磨礦質量濃度、螺旋分級機溢流質量濃度、水力旋流器給礦壓力、水力旋流器給礦質量濃度等。保持球磨機給礦量穩定,使其不波動或波動範圍很小,對穩定產品質量、穩(wen)定(ding)球(qiu)磨(mo)機(ji)磨(mo)礦(kuang)過(guo)程(cheng)都(dou)是(shi)很(hen)重(zhong)要(yao)的(de)因(yin)素(su),同(tong)時(shi)從(cong)經(jing)濟(ji)效(xiao)益(yi)的(de)角(jiao)度(du)考(kao)慮(lv)應(ying)保(bao)證(zheng)球(qiu)磨(mo)機(ji)的(de)最(zui)大(da)處(chu)理(li)能(neng)力(li)。對(dui)於(yu)格(ge)子(zi)型(xing)球(qiu)磨(mo)機(ji)來(lai)說(shuo),一(yi)個(ge)比(bi)較(jiao)合(he)適(shi)的(de)磨(mo)礦(kuang)質(zhi)量(liang)濃(nong)度(du)是(shi)實(shi)現(xian)球(qiu)磨(mo)機(ji)磨(mo)礦(kuang)效(xiao)率(lv)高(gao)低(di)的(de)前(qian)提(ti),磨(mo)礦(kuang)質(zhi)量(liang)濃(nong)度(du)的(de)過(guo)高(gao)或(huo)過(guo)低(di)都(dou)會(hui)產(chan)生(sheng)負(fu)麵(mian)的(de)影(ying)響(xiang),比(bi)如(ru)球(qiu)磨(mo)機(ji)漲(zhang)肚(du)等(deng)事(shi)故(gu)。螺(luo)旋(xuan)分(fen)級(ji)機(ji)溢(yi)流(liu)質(zhi)量(liang)濃(nong)度(du)在(zai)某(mou)種(zhong)程(cheng)度(du)上(shang)與(yu)一(yi)次(ci)分(fen)級(ji)溢(yi)流(liu)粒(li)度(du)有(you)一(yi)定(ding)的(de)關(guan)係(xi),並(bing)且(qie)溢(yi)流(liu)質(zhi)量(liang)濃(nong)度(du)的(de)高(gao)低(di)將(jiang)會(hui)影(ying)響(xiang)分(fen)級(ji)機(ji)返(fan)砂(sha)的(de)多(duo)少(shao)和(he)返(fan)砂(sha)的(de)質(zhi)量(liang)濃(nong)度(du),從(cong)而(er)影(ying)響(xiang)球(qiu)磨(mo)機(ji)的(de)磨(mo)礦(kuang)效(xiao)率(lv)和(he)球(qiu)磨(mo)機(ji)的(de)處(chu)理(li)量(liang),因(yin)此(ci)控(kong)製(zhi)分(fen)級(ji)機(ji)溢(yi)流(liu)質(zhi)量(liang)濃(nong)度(du)是(shi)控(kong)製(zhi)產(chan)品(pin)質(zhi)量(liang)好(hao)壞(huai)、磨mo礦kuang效xiao率lv的de重zhong要yao環huan節jie。為wei了le保bao證zheng水shui力li旋xuan流liu器qi在zai生sheng產chan上shang的de穩wen定ding及ji其qi產chan品pin質zhi量liang的de穩wen定ding,必bi須xu控kong製zhi旋xuan流liu器qi的de給gei礦kuang壓ya力li,保bao證zheng旋xuan流liu器qi的de工gong作zuo狀zhuang況kuang最zui佳jia(沉砂呈傘裝,角度不能過大或過小),防fang止zhi產chan品pin質zhi量liang的de波bo動dong,同tong時shi也ye防fang止zhi旋xuan流liu器qi給gei礦kuang泵beng池chi被bei打da空kong或huo打da冒mao。旋xuan流liu器qi的de溢yi流liu粒li度du與yu旋xuan流liu器qi的de給gei礦kuang質zhi量liang濃nong度du有you一yi定ding的de關guan係xi,此ci參can數shu配pei合he旋xuan流liu器qi的de給gei礦kuang壓ya力li將jiang是shi控kong製zhi旋xuan流liu器qi分fen級ji效xiao率lv的de重zhong要yao工gong作zuo參can數shu。以yi上shang各ge種zhong因yin素su的de相xiang互hu影ying響xiang,共gong同tong作zuo用yong,決jue定ding了le磨mo礦kuang作zuo業ye的de好hao壞huai。正zheng是shi從cong該gai工gong藝yi的de生sheng產chan技ji術shu要yao求qiu及ji工gong藝yi特te點dian設she計ji了le磨mo礦kuang過guo程cheng綜zong合he自zi動dong化hua係xi統tong。
4 結束語 針對磨礦過程當中存在的大慣性、時變、非線性、工藝參數(磨礦粒度、磨礦質量濃度、磨機負荷)nanyizaixianceliangdengzonghefuzaxing,tichuleyoumokuangzhinengyouhuashedingxitonghemokuanghuilukongzhixitongzuchengdeshixianmokuangliduhemojichuliliangyouhuakongzhidemokuangguochengzhinengyouhuakongzhicelve。jiehexuankuangchangshengchanguocheng,tichuleyouzhinengyouhuakongzhixitong、運行過程管理係統組成的兩層結構的磨礦過程綜合自動化係統。該係統可以推廣到鋼鐵、有色金屬、選礦、水泥等行業的複雜生產過程,有廣闊應用前景。 參考文獻 [1] Duarte M, Redard J. Grinding operation optimization of the CODELCO-Andina concentrator plant[J]. Minerals Engineering, 1998, 11(12): 1119-1142. [2] Manuel D, Florencio S. A comparative experimental study of five multivariable control strategies applied to a grinding plant[J]. Powder Technology, 1999, 104(1): 1-28. [3] Andre P, Daniel H. A survey of grinding circuit control methods: from decentralized PID controllers to multivariable predictive controller[J]. Powder Technology, 2000, 108(2): 103-115. [4] Herbst J A and Pate W T. Object components for comminution system softsensor design[J]. Powder Technology, 1999, 105(1): 424-429. [5] 歐洲鋼鐵工業聯盟著. 歐洲鋼鐵工業技術發展指南[M]. 韓靜濤譯. 北京: 中國金屬學會,1999. [6] Houseman L A, Schubert J H, Hart J R and Carew W D. PlantStar 2000: a plant-wide control platform for minerals processing[J]. Minerals Engineering, 2001, 14(6): 593-600. [7] 柴天佑,李小平,周曉傑,等. 基於三層結構的金礦企業現代集成製造係統[J].控製工程,2003, 10(1): 18-22.