ISSN:0734-9343    

DOI:10.1080/07349349908945588

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Proper analysis of washability data can lead to the development of a maximum yield coal preparation plant flow sheet. Simulations, as simple as spreadsheet mass and water balancing, are important in examining yield maximization and middlings liberation. Key to such attribute tracking flow sheet simulations is the distribution model, expressing the probability of a species reporting to the product stream. There are many such equations proposed in the literature. This paper examines a functional form that can represent or fit most of the proposed distribution functions. Such a general function is very convenient in a general simulator, because the user need only define the relevant parameters instead of the appropriate equation and parameters.

ISSN:0734-9343    

DOI:10.1080/07349349908945589

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The MODSIM mineral processing plant simulator is used to find optimal combinations of target separation specific gravities for the separation units in a typical coal washing plant. The plant is set up to wash three size fractions separately in parallel streams. Two alternative flowsheets are examined: the first includes a dense-medium vessel, a dense-medium cyclone and a 2-stuge water-only cyclone, and the second includes a dense-medium vessel, a shaking table, a spiral separator and a bank of flotation cells. A simple graphical construction is used to find the optimal separation densities using data thai is generated by the simulator. Results are presented as optimal ash content - total yield curves for the combined clean coal products.

ISSN:0734-9343    

DOI:10.1080/07349349908945590

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The coal specifications for coal-burning power plants usually contain a requirement for a maximum moisture content in order to prevent coal handling problems and to minimize evaporative losses in the boiler. As most coal cleaning processes are water-based, dewatering and sometimes thermal drying are required to meet moisture specifications. Screens are often used for dewatering and are followed often by centrifuges or filters to reduce the moisture content further.

ISSN:0734-9343    

DOI:10.1080/07349349908945591

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A mathematical model employing the discrete element method is used to study the stratification of particles during jigging. This model is used to simulate jigging of binary as well as ternary particles. In particular, effect of amplitude and frequency of pulsation on the stratification behavior of the particles is analyzed. The existence of an optimal condition in terms of amplitude and frequency of pulsation is established. Furthermore, the pulsation of fluid is controlled to generate different waveforms and its effect in turn on the stratification of the particles is investigated. It is shown that the numerical results correlate well with the available data in the literature.

ISSN:0734-9343    

DOI:10.1080/07349349908945592

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Mayer's potential energy theory is one of the most widely accepted theories describing jigging. While it represented a substantial contribution to jig theory, the potential energy theory can not be applied directly to describe real jigging operations. A modification to that theory has been made recently and is called the dispersion model of jigging. That model, however, is limited to describing jigging of particles of uniform size. A procedure that uses the Monte Carlo technique and Mayer's principle has been developed, and is used to simulate jigging of particulate mixtures of variable size and density. It is demonstrated that for the case of monosize feeds with variable densities the simulation procedure provides results identical to those from the dispersion model. Further, in the case of binary-sized feeds, it is shown that a layer of fines accumulates in the top of the bed, while a greater proportion of coarse material is observed in the bottom of the bed.

ISSN:0734-9343    

DOI:10.1080/07349349908945593

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A significant effort has been made during the past decade to develop gravity separators for treating fine particles. As a result, several enhanced gravity separators have been developed and commercialized. The Altair Centrifugal Jig is an enhanced gravity separator that provides relatively efficient separations on +25 μm size fractions. An experimental program conducted on −600 μm coal found that the Altair Jig reduced the ash content of the 600×44 urn material from about 30% to 10% with an 86% combustible recovery value. The pulse water pressure, feed volumetric rate and ragging volume were found to be the key operating parameters affecting the separation performance indices obtained from the process. A low density cut point of 1.55 with a probable error value of 0.09 was indicative of the high process efficiency values achievable by the Altair Jig.

ISSN:0734-9343    

DOI:10.1080/07349349908945594

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A novel multistage column has been successfully developed for fine coal beneficiation. This new column uses vortex-inducing contactors as stages to enhance the separation process. This paper presents an experimental study of the beneficiation characteristics or such a multistage column in terms of recovery rate, heating value recovery and impurity rejection. The paper also discusses the effects of dosage on the column performance. The results are compared with those obtained from the conventional column (without vortex-inducing contactors).

ISSN:0734-9343    

DOI:10.1080/07349349908945595

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor