Coal Ash Beneficiation and Utilization in Coal Separation Process
In recent years, coal production and consumption increased dramatically, especially in China. So, more and more attentions have been paid to coal preparation and coal ash utilization with the growing concern about the pollution by fly ash. The unburned carbon in fly ash significantly affects its utilization in many fields, especially in concrete production industry. Technologies such as flotation, triboelectrostatic separation and carbon burnout have been developed to remove carbon from coal ash. This paper introduces chemical compositions of a typical coal ash and a dry beneficiation method. For some kinds of fly ash, magnetically stabilized fluidized bed was studied to recover magnetic pearls from fly ash. The magnetic pearls are mainly composed of Fe3O2 and Fe3O4 and are mostly hollow spheres. The size distributions of three kinds of magnetic pearls are from 300 to 25 µm. A magnetic pearls fluidized bed and a magnetically stabilized magnetic pearls fluidized bed for coal dry separation are studied in the paper.
Penentuan Kandungan Logam Magnetik Komponen Penyusun Abu Layang Batubara
Telah dilakukan penelitian penentuan kandungan logam magnetik penyusun abu layang batubara. Abu layang merupakan material berupa serbuk halus yang dihasilkan dari pembakaran batubara dengan kadar sekitar 80-90% dari total abu yang dihasilkan. Komponen utama dari abu layang batubara adalah silika (SiO 2 ), alumina (Al 2 O 3 ), dan besi oksida (Fe 2 O 3 ) . Sampel abu layang batubara yang digunakan berasal dari PLTU Tanjung Jati Jepara. Komponen magnetik abu layang batubara diperoleh dengan cara memisahkan abu layang menggunakan batang magnet. Proses destruksi pada sampel abu layang dan komponen magnetik menggunakan aqua regia. Metode untuk menentukan besarnya kadar unsur-unsur magnetik yang terkandung dalam abu layang adalah metode spektrofotometri serapan atom (AAS). Hasil penelitian menunjukkan pada sampel abu layang batubara mempunyai kadar logam Fe sebesar 6,1 7 %, logam Al sebesar 3,96%, logam Mn sebesar 1,49% dan logam Cu sebesar 0,0045%. Kadar logam magnetik yang paling dominan pada komponen magnetik abu layang adalah logam Fe sebesar 8,2 8 %, kemudian logam Al sebesar 4,1 5 %, logam Mn sebesar 2,06% dan logam Cu sebesar 0,0027%. Telah dilakukan penelitian penentuan kandungan logam magnetik penyusun abu layang batubara. Abu layang merupakan material berupa serbuk halus yang dihasilkan dari pembakaran batubara dengan kadar sekitar 80-90% dari total abu yang dihasilkan. Komponen utama dari abu layang batubara adalah silika (SiO 2 ), alumina (Al 2 O 3 ), dan besi oksida (Fe 2 O 3 ) . Sampel abu layang batubara yang digunakan berasal dari PLTU Tanjung Jati Jepara. Komponen magnetik abu layang batubara diperoleh dengan cara memisahkan abu layang menggunakan batang magnet. Proses destruksi pada sampel abu layang dan komponen magnetik menggunakan aqua regia. Metode untuk menentukan besarnya kadar unsur-unsur magnetik yang terkandung dalam abu layang adalah metode spektrofotometri serapan atom (AAS). Hasil penelitian menunjukkan pada sampel abu layang batubara mempunyai kadar logam Fe sebesar 6,1 7 %, logam Al sebesar 3,96%, logam Mn sebesar 1,49% dan logam Cu sebesar 0,0045%. Kadar logam magnetik yang paling dominan pada komponen magnetik abu layang adalah logam Fe sebesar 8,2 8 %, kemudian logam Al sebesar 4,1 5 %, logam Mn sebesar 2,06% dan logam Cu sebesar 0,0027%.
Computer-Aided System of Virtual Testing of Gas Turbine Engines
The article describes the concept of a virtual lab that includes subsystem of gas turbine engine simulation, subsystem of experiment planning, subsystem of measurement errors simulation, subsystem of simulator identification and others. The basis for virtual lab development is the computer-aided system of thermogasdynamic research and analysis “ASTRA”. The features of gas turbine engine transient modes simulator are described. The principal difference between the simulators of transient and stationary modes of gas turbine engines is that the energy balance of the compressor and turbine becomes not applicable. The computer-aided system of virtual gas turbine engine testing was created using the developed transient modes simulator. This system solves the tasks of operational (throttling, speed, climatic, altitude) characteristics calculation, analysis of transient dynamics and selection of optimal control laws. Besides, the system of virtual gas turbine engine testing is a clear demonstration of gas turbine engine working process and the regularities of engine elements collaboration. The interface of the system of virtual gas turbine engine testing is described in the article and some screenshots of the interface elements are provided. The developed system of virtual gas turbine engine testing provides means for reducing the laboriousness of gas turbine engines testing. Besides, the implementation of this system in the learning process allows the diversification of lab works and therefore improve the quality of training.