摘要:

Horizontal vacuum belt filters provide a very efficient means of filtering fine coal slurries ( nominally minus 0.5mm). Depending on the nature of the coal processed, industry' s best practice with this technology typically leads to cake discharge moisture in excess of 25% Recent work [ 1] has permitted identification of filter cake microstructure as a major limiting factor.for moisture removal that is distinct from coal properties. This result suggested that modifying and possibly controlling cake microstructure could offer potential for moisture reduction in vacuum filters. The paper discusses the findings of a laboratory study involving mechanical agitation of fine coal filter cakes during the drying phase using a helical ribbon mixer. The rational that led to the experimental approach used in this work is detailed. Test results are reported which confirm that alteration of cake microstructure during the drying phase of the vacuum filtration cycle has immediate and positive impact on cake drying. Moisture reductions up to 3% were measured with fine bituminous coal filter cakes. Analysis of the experimental results reveals that the effect of filter cake mixing on cake moisture reduction depends strongly on the time at which mixing is initiated during the drying cycle and the size distribution of the filter cake particles. The practical potential of the mixing process is also discussed.

ISSN:0734-9343    

DOI:10.1080/07349340008945617

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The aim of this paper is to investigate the feasibility of using clay suspensions in dynamic dense medium separation of post-consumer plastics. The Theological behavior of suspensions formed with different commercial clay samples was studied to ascertain that both viscosity and stability could be maintained in the range required by dense medium separation systems. Suspensions made with a selected clay sample were used in a laboratory test rig equipped with a conical cyclone and a cylindrical cyclone with peripheral underflow discharge. Preliminary separation tests were carried out using different density plastic tracers. The results with both separators demonstrated that the separation of two plastics of different densities can be obtained.

ISSN:0734-9343    

DOI:10.1080/07349340008945618

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Hindered-bed classifiers have recently received significant attention for the potential of achieving effective density-based separations. Although the fundamental principles of hindered-bed classifiers are relatively simple, the complex interactions between the operating parameters provide a degree of difficulty that hinders the ability for on-line plant optimization. Thus, a dynamic population balance model was developed to evaluate and optimize the separation performance achievable on the basis of density by a hindered-bed classifier for the cleaning of fine coal. The steady-state results of the model include partition curves as a function of particle size and density as well as metallurgical data. A statistical comparison of the simulation results with those obtained from industrial units reveal a high level of accuracy with adjusted R2 values greater than 0.95. Simulation results indicate the potential for efficient density-based separations over a particle size range of 3:1.

ISSN:0734-9343    

DOI:10.1080/07349340008945619

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Computer simulation of the control system for the heavy media coal washing process has been presented in the paper. The simulation model applies the Simulink module of the Matlab 5.1 software package and allows to monitor the variations of all system variables for different sets of control parameters. The densities and levels of liquids in tanks, the operation of controlled valves and liquid distributors are monitored and displayed as functions of time. The model gives a good approximation of the industrial system and allows to optimize the control algorithm and parameters of the discrete controller. The control algorithm, the block schemes of the simulation model and simulation results have been presented in the paper. Experience derived from the industrial application of computer-based heavy media control systems, designed with the use of simulation program, have also been discussed.

ISSN:0734-9343    

DOI:10.1080/07349340008945620

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:0734-9343    

DOI:10.1080/07349340008945616

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor