Coal combined-cycle plant with working medium heating in gas-turbine cycle in periodic regenerative heat exchangers

The authors consider the technique based on application of air heated in periodic regenerative ceramic heat exchangers by coal powder combustion products as a gas-turbine working medium to be rather promising for being studied. In this case the working medium can be heated to essentially higher temperatures than at coal combustion in the pressurized fluidized bed. Here only a small amount of ash contained in the coal combustion products settles in the ceramic heat exchanger and then penetrates into the heated air. It allows supporting high air temperature before the turbine at an acceptable level of ash concentration at gas turbine inlet. To substantiate the efficiency of this technique the authors have developed the technological scheme of coal-fired combined cycle plant with gas-turbine cycle working medium heated in periodic regenerative heat exchangers; the mathematical models of regenerative ceramic heat exchangers with cylindrical conduits and coal-fired combined cycle plant were developed. The paper introduces the results based on a detailed mathematical model of the optimization technical and economic studies of coal-fired combined cycle plant with gas-turbine cycle working medium heated in periodic regenerative heat exchangers

MODELLING OF PARTICLES AGLOMERATION IN THE ACOUSTIC FIELD / DALELIŲ AGLOMERACIJOS AKUSTINIAME LAUKE MODELIAVIMAS

The article includes particles agglomeration principles analysis. Forces describes with the equations operating particle of its moving in the vibes. It presents equations of particle movement speed and trajectory estimation. It have performed agglomerations simulation of two identical (5 mm and 5 mm) and different (5 mm and 10 mm) diameters particles in the acoustic field using the discrete element method (DEM). The results showed that the two equal diameter particle agglomeration gravity affects at 8 kHz acoustic signal frequency. Santrauka  Straipsnyje pateikta dalelių aglomeracijos dėsnių analizė. Lygtimis aprašytos jėgos, veikiančios dalelę, judančią terpėje. Pateiktos dalelės judėjimo greičio ir trajektorijos nustatymo lygtys, atliktas dviejų vienodų (5 m ir 5 m) ir skirtingų (5 m ir 10 m) skersmenų dalelių aglomeracijos akustiniame lauke modeliavimas, taikant diskrečiųjų elementų metodą (DEM). Gavus rezultatus nustatyta, kad dviejų vienodo skersmens dalelių aglomeracijai gravitacija turi įtakos tik esant 8 kHz akustinio signalo dažniui. Reikšminiai žodžiai: akustinis laukas, dalelės, aglomeracija, DEM