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Number of results: 4
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Abstract

In recent years, the Budryk Coal Mine (KWK Budryk) reached the mining depth of 1300 m, where there is about 160 million tons of coal, including 120 million tons of coking coal (type 35). The task of the Coal Processing Plant complex modernization was undertaken. The article presents the modernization of coal screening, classification and dewatering systems at the KWK Budryk Processing Plant and the implementation of screening of PROGRESS ECO sp. z o.o. SK. The modernization project defined the following technical requirements for all screens in the KWK Budryk Coal Processing Plant extension project: - Vibrating screens with a linear type drive with a drive unit placed on the drive beam of the trommel screen in the form of vibration generators; - Screen drives equipped with a starting-braking device; - The use of main screen drive bearings with a nominal service life of at least 40,000 man-hours; - All work surfaces made of materials with a strength of up to 80 mm grain and abrasion resistance; side strips and sieves fixed in a way ensuring trouble-free operation, and at the same time quick and easy replacement; - Sheets made of stainless steel; - Side walls, beams and other elements attached to them connected with screws using a system protecting against corrosion and elements separation; - The use of a work parameters monitoring and visualization system, i.e. - pitch of the riddle, - bearing operating temperatures and the condition of their wear. Three types of screens were provided: - PWP1-1Z-2,8x6,0 screeners that alternatively perform sieving or desliming processes, - PWP1-2.4x6.0 screening machines performing desliming processes, - PWP1-2.0x6.0 screens performing the classification process.
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Abstract

Control of the technological processes of coal enrichment takes place in the presence of wide disturbances. Thus, one of the basic tasks of the coal enrichment process control systems is the stabilization of coal quality parameters at a preset level. An important problem is the choice of the controller which is robust for a variety of disturbances. The tuning of the controller parameters is no less important in the control process . Many methods of tuning the controller use the dynamic characteristics of the controlled process (dynamic model of the controlled object). Based on many studies it was found that the dynamics of many processes of coal enrichment can be represented by a dynamic model with properties of the inertial element with a time delay. The identification of object parameters (including the time constant) in industrial conditions is usually performed during normal operation (with the influence of disturbances) from this reason, determined parameters of the dynamic model may differ from the parameters of the actual process. The control system with controller parameters tuned on the basis of such a model may not satisfy the assumed control quality requirements. In the paper, the analysis of the influence of changes in object model parameters in the course of the controlled value has been carried out. Research on the controller settings calculated according to parameters T and τ were carried out on objects with other parameter values. In the studies, a sensitivity analysis method was used. The sensitivity analysis for the three methods of tuning the PI controller for the coal enrichment processes control systems characterized by dynamic properties of the inertial element with time delay has been presented. Considerations are performed at various parameters of the object on the basis of the response of the control system for a constant value of set point. The assessment of considered tuning methods based on selected indices of control quality have been implemented.
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Abstract

The analysis of leaching behavior of harmful substances, such as arsenic, is one of the parameters of risk assessment resulting from the storage or economic use of coal waste. The leachability depends both on the environmental conditions of the storage area as well as on the properties of the waste material itself. There are a number of leaching tests that allow to model specific conditions or measure the specific properties of the leaching process. The conducted research aimed at comparing two methods with different application assumptions. The study of arsenic leaching from waste from the hard coal enrichment process was carried out in accordance with the Polish PN-EN 12457 standard and the US TCLP procedure. The leaching results obtained with both methods did not exceed the limit values of this parameter, defined in the Polish law. Both methods were also characterized by the good repeatability of the results. The use of an acetic acid solution (TCLP method) resulted in three times higher arsenic leaching from the examined waste compared to the use of deionized water as a leaching fluid (method PN-EN 12457). Therefore, the use of organic acid tests for mining waste intended for storage with municipal waste should be considered, as the results of the basic test based on clean water leaching may be inadequate to the actual leaching of arsenic under such environmental conditions.
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Abstract

The coal fed to gravity enrichment consists of coals coming from different deposits and exploitation fronts. These coals differ in quality parameters, especially the amount of gangue (stone) changing over time. This results in the instability of work, especially jiggers, which have a relatively low accuracy assessed by probable scattering or imperfection rates. This deteriorates the quality of the concentrate obtained, the quality parameters of which change over time. The improvement of jiggers work would be possible by averaging the feed. This process is practically impossible due to the failure to design such a node during plant construction, which are, in most cases, directly related to the shaft. In the article, the authors propose to solve the process of averaging the feed before directing it to the enrichment process in jiggers by introducing its deshaling in vibratory- air separators of the FGX type.
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