1、1 英文翻译原文Coal preparation plant optimization: A critical review of theexisting methodsV. Gupta, M.K. MohantyDepartment of Mining and Mineral Resources Engineering, Southern Illinois University at Carbondale, Carbondale,Illinois 62901-6603, United StatesReceived 19 July 2005; received in revised form
2、13 November 2005; accepted 15 November 2005Available online 4 January 2006Abstract：A 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 increme
3、ntal product quality approach. Individual cleaning circuits are operated at the same specific incremental product quality so that the targeted overall plant product quality is achieved. Over the years, it has been well established that equal incremental product quality approach maximizes plant-yield
4、 for a given product quality constraint.However, while dealing with multiple quality constraints, the incremental quality approach may not provide a complete solution to the optimization problem. It may be intuitive to realize that the dirtiest particle(s) in a coal product, with respect to ash onte
5、nt, may not be the same particle(s) with respect to sulfur content. Therefore, with increasing number of product quality constraints, which may include (but not limited to) limiting ash, sulfur and trace element contents, the plant has to be optimized based on each incremental product quality. Under
6、standably, the operating points selected for each circuit to maximize plant-yield based 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 ultip
7、le product quality constraints have been reviewed in detail in this publication with an example of ash and sulfur data collected from an operating coal preparation plant.D 2005 Elsevier B.V. All rights reserved.Keywords: coal; plant optimization; incremental product quality; coal washability1. Intro
8、ductionBased on the size consist of the Run-of-mine (ROM) coal, a preparation plant utilizes three or four individual circuits to clean the entire ROM coal. For example, coal coarser than 12.5 mm may be cleaned in a heavy medium vessel circuit, 12.5 1 mm in a heavy medium cyclone circuit, 1 mm 150 A
9、m in a spiral circuit and minus 150 Am size coal in a flotation circuit. Typically, product quality measure such as ash content from each circuit is maintained at nearly the same level as the target ash content for the overall plant. In other words, if a plant contract requires product specification
10、s of 8% ash, the operating conditions in the individual circuits are adjusted so that the ash contents of the individual circuit products are approximately 8%. Although this approach of producing equal average product quality from each circuit provides a simplistic solution to satisfy contract speci
11、fications, it does not guarantee the maximum possible plant yield.Incremental product quality concept is commonly used to maximize plant yield for a given quality constraint. By definition, incremental product quality refers to the quality of the dirtiest particle(s) present in any coal product, whe
12、reas the average product quality refers to the overall quality of the composite coal product.Numerous studies have been conducted in the past to develop suitable procedures for maximizing overall plant yield while satisfying a desired average product quality. Sarkar et al. (1960) suggested a graphic
13、al ap- proach for maximization of yield of composite clean coal at a desired ash content. It was suggested that cleaning of coarser coal at a higher ash content and finer coal at a relatively lower ash content gives the maximum yield while satisfying the given product ash constraint. Walters and Ram
14、ani (1976) developed a computer based plant optimization model in which the separating gravity of the small coal is held constant while the separating gravity of the coarse coal is incremented until the desired product quality is achieved. Abott (1982) derived an equation to prove that the optimum c
15、onditions for maximum profit from a blend of coal produced by two different cleaning processes occurs when the instantaneous ash (incremental ash) contents of both clean products are equal. Salama (1986, 1991 and 1998) and King (1999) developed graphical and numerical echniques to optimize the yield
16、 of a plant at a given product quality constraint. Graphical ethods were based on the Mayer curve (M-curve) to determine the optimum cut points of separation which maximized the plant yield at a given product ash content. Rayner (1987) also utilized the graphical technique of plotting M-curve for yield aximization of a plant at a given ash constraint. Romberg (1990) developed the optimization oftware, COALTROL, utilizing the M-curve for yield maximization. These g
