PAPERS SELECTED FOR THE SYMPOSIUM

• PLASMA-FUEL SYSTEMS APPLICATION IN HEAT-AND-POWER ENGINEERING.

  E.I. Karpenko - Branch Centre of Plasma-Power Technologies of Russian J.S.Co. “UPS of Russia”, Gusinoozersk, Russia, V.E. Messerle - Research Institute of Experimental and Theoretical Physics, Almaty, Kazakhstan, A.B. Ustimenko - Research Department of Plasmotechnics, Almaty, Kazakhstan

  Abstract Text

  To increase efficiency of solid fuel utilization, to decrease share of fuel oil and natural gas in fuel balance of Thermal Power Plants (TPP) and to decrease harmful emissions plasmachemical technology of coals ignition, gasification and combustion was developed. Plasma-fuel... show full text »
  Abstract Text

  To increase efficiency of solid fuel utilization, to decrease share of fuel oil and natural gas in fuel balance of Thermal Power Plants (TPP) and to decrease harmful emissions plasmachemical technology of coals ignition, gasification and combustion was developed. Plasma-fuel systems (PFS) were created to realize this technology. PFS are combination of pulverized fuel burners with DC arc plasma torches. The main idea of PFS is to replace fuel oil or natural gas by products of plasmachemically processed pulverized coal. It was experimentally proven that PFS increases efficiency of coal ignition and combustion, eliminates fuel oil expenditure for start up and flame stabilization, decreases unburned carbon, NOx, SOx, and V2O5 emission. PFS have been tested in different countries at 29 power boilers steam-productivity 75 to 670 t/h equipped with different types of pulverized coal burners. At PFS testing power coals of all ranks (brown, bituminous, anthracite and their mixtures) were incinerated. Volatile content of them was from 4 to 50%, ash varied from 15 to 56% and heat of combustion was from 1600 to 6000 kcal/kg. Using PFS fuel oil is replaced by pulverised coal, which is a subject to thermochemical pre-process to the combustion within the PFS. In this technology part of the coal/air mixture is fed into the burner where the plasma-flame, having a locally high concentration of energy, induces gasification of the coal and partial oxidation of the char carbon. The resulting coal/air mixture is deficient in oxygen, the carbon being mainly oxidized to carbon monoxide. As a result, a highly reactive mixture of combustible gases and partially oxidized char particles are obtained at the exit of the PFS. On entry to the furnace, this combustible mixture is easily ignited. This allows prompt ignition and much enhanced flame stability of the main portion of the coal flame which is not directly treated by the plasma. Activation of coal combustion by this means eliminates the need for supplementary fuel consumption (fuel oil or natural gas), traditionally used for the start-up of a coal-fired furnace. Recently interest to application of the PFS at TPP increases except China where 87 % of electrical power is produced at coal fired TPP in Kazakhstan, Russia, Turkey, Korea, and India in which segment of pulverized coal fired TPP in power engineering is 80, 30, 47, 50, and 70% correspondingly. At present for some of these countries TPP PFS with DC plasma torches of 200 kW power are projected. The engineering solutions are being developing for the boilers of steam productivity of 75 to 1650 t/h at Shekhtinsk TPP (Kazakhstan), Reftinsk TPP (Russia), Yatagan TPP (Turkey), Shan-si TPP, South See – Tzin-nen TPP (China). « hide
  Symposium Session: Power Plants life cycle extension, new clean coal technologies | Produženja radnog veka elektrana i novih ekološki čistih tehnologija

• MODELLING OF PLASMA SUPPORTED COAL COMBUSTION IN FULL-SCALE BOILER

  A.S. Askarova - Department of Physics, al-Farabi Kazakh National University, Almaty, Kazakhstan, E.I. Karpenko - Branch Centre of Plasma-Power Technologies of Russian J.S.Co. “UPS of Russia”, Gusinoozersk, Russia, O.A. Lavrichshev - Research Institute of Experimental and Theoretical Physics, Almaty, Kazakhstan, V.E. Messerle - Research Institute of Experimental and Theoretical Physics, Almaty, Kazakhstan, A.B. Ustimenko - Research Department of Plasmotechnics, Almaty, Kazakhstan

  Abstract Text

  Traditional technologies of solid fuels combustion account for higher level of pollutant emissions in comparison with incineration of liquid and gas fuels. However, the fraction of heat and electric power produced by coal-fired thermal power plants will increase and by... show full text »
  Abstract Text

  Traditional technologies of solid fuels combustion account for higher level of pollutant emissions in comparison with incineration of liquid and gas fuels. However, the fraction of heat and electric power produced by coal-fired thermal power plants will increase and by 2020 it will have exceeded 50%. Plasma activation promotes more effective and environmentally friendly power coals usage. Effective development of a new coal technology is impossible without modelling and numerical investigation of the processes. This paper presents the results of numerical simulations of the plasma thermochemical enhancement of coal for ignition and combustion in a furnace chamber. The calculations were performed for a low-rank bituminous coal of 44% ash content. Two kinetic mathematical models were used for investigation of the processes of air-fuel mixture plasma activation, ignition and combustion. The first was a 1D model “Plasma-coal”. It describes a two-phase chemically reactive flow in a plasma-chamber with an internal source of heat, i.e. an arc or plasma flame. The kinetic scheme consists of 116 chemical reactions including stages of coal devolatilisation, reactions of the gas phase volatile material and heterogeneous reactions of carbon oxidation. Data to enable a 3D numerical simulation of coal combustion in a furnace chamber were collected. The 3D numerical experiments were performed with the help of the “FLOREAN” code applied to a boiler having 475 t/h steam productivity. The furnace is equipped with 12 tangential three-channel burners. Burners are mounted in two layers, 6 burners in every layer. A comparative analysis of the coal combustion process enhanced through four, six and twelve plasma-fuel systems with and without plasma activation was carried out. Distributions of temperatures, velocities, component concentrations (CO, CO2, N2, NOX, O2, etc.) were determined for different sections of the furnace. As a result of the numerical experiments, the advantages of the plasma technology have been clearly demonstrated. The combined application of the two well-known and reliable models has enabled a comprehensive image of the processes occurring in plasma-fuel systems for coal activation to be obtained. Comparison of the calculated results with the experimental data obtained in the laboratory and under industrial conditions reveals good agreement. « hide
  Symposium Session: Power Plants life cycle extension, new clean coal technologies | Produženja radnog veka elektrana i novih ekološki čistih tehnologija