外文原文-选煤厂优化现有优化方法的修正.pdf

1、Coal preparation plant optimization:A critical review of theexisting methodsV.Gupta1,M.K.Mohanty*Department of Mining and Mineral Resources Engineering,Southern Illinois University at Carbondale,Carbondale,Illinois 62901-6603,United StatesReceived 19 July 2005;received in revised form 13 November 20

2、05;accepted 15 November 2005Available online 4 January 2006AbstractA coal preparation plant typically operates with multiple cleaning circuits to clean individual size fractions of run-of-mine coal.Coal preparation plants are traditionally optimized using the equalization of incremental product qual

3、ity approach.Individualcleaning circuits are operated at the same specific incremental product quality so that the targeted overall plant product quality isachieved.Over the years,it has been well established that equal incremental product quality approach maximizes plant-yield for agiven product qu

4、ality constraint.However,while dealing with multiple quality constraints,the incremental quality approach may not provide a completesolution to the optimization problem.It may be intuitive to realize that the dirtiest particle(s)in a coal product,with respect toash content,may not be the same partic

5、le(s)with respect to sulfur content.Therefore,with increasing number of product qualityconstraints,which may include(but not limited to)limiting ash,sulfur and trace element contents,the plant has to be optimizedbased on each incremental product quality.Understandably,the operating points selected f

6、or each circuit to maximize plant-yieldbased on incremental ash content,may not be suitable for obtaining maximum plant yield based on incremental sulfur content.These limitations of the equalization of incremental product quality approach to satisfy multiple product quality constraints havebeen rev

7、iewed in detail in this publication with an example of ash and sulfur data collected from an operating coal preparationplant.D 2005 Elsevier B.V.All rights reserved.Keywords:coal;plant optimization;incremental product quality;coal washability1.IntroductionBased on the size consist of the Run-of-mine

8、(ROM)coal,a preparation plant utilizes three or four individualcircuits to clean the entire ROM coal.For example,coalcoarser than 12.5 mm may be cleaned in a heavymedium vessel circuit,12.5?1 mm in a heavy mediumcyclone circuit,1 mm?150 Am in a spiral circuit andminus 150 Am size coal in a flotation

9、 circuit.Typically,product quality measure such as ash content from eachcircuit is maintained at nearly the same level as thetarget ash content for the overall plant.In other words,if a plant contract requires product specifications of 8%ash,the operating conditions in the individual circuitsare adj

10、usted so that the ash contents of the individualcircuit products are approximately 8%.Although thisapproach of producing equal average product quality0301-7516/$-see front matter D 2005 Elsevier B.V.All rights reserved.doi:10.1016/j.minpro.2005.11.006*Corresponding author.Tel.:+1 618 453 7910;fax:+1

11、 618 4537455.E-mail address:mohantyengr.siu.edu(M.K.Mohanty).1Tel.:+1 618 453 7910;fax:+1 618 453 7455.Int.J.Miner.Process.79(2006) each circuit provides a simplistic solution to sa-tisfy contract specifications,it does not guarantee themaximum possible plant yield.Incremental product quality concep

12、t is commonlyused to maximize plant yield for a given quality con-straint.By definition,incremental product quality refersto the quality of the dirtiest particle(s)present in anycoal product,whereas the average product quality refersto the overall quality of the composite coal product.Numerous studi

13、es have been conducted in the past todevelop suitable procedures for maximizing overallplant yield while satisfying a desired average productquality.Sarkar et al.(1960)suggested a graphical ap-proach for maximization of yield of composite cleancoal at a desired ash content.It was suggested thatclean

14、ing of coarser coal at a higher ash content andfiner coal at a relatively lower ash content gives themaximum yield while satisfying the given product ashconstraint.Walters and Ramani(1976)developed acomputer based plant optimization model in whichthe separating gravity of the small coal is held cons

15、tantwhile the separating gravity of the coarse coal is incre-mented until the desired product quality is achieved.Abott(1982)derived an equation to prove that theoptimum conditions for maximum profit from a blendof coal produced by two different cleaning processesoccurs when the instantaneous ash(in

16、cremental ash)contents of both clean products are equal.Salama(1986,1991 and 1998)and King(1999)developedgraphical and numerical techniques to optimize theyield of a plant at a given product quality constraint.Graphical methods were based on the Mayer curve(M-curve)to determine the optimum cut points of separa-tion which maximized the plant yield at a given productash content.Rayner(1987)also utilized the graphicaltechnique of plotting M-curve for yield maximizationof a plant at a given ash cons