Assessment of slagging and polluting properties of coals burned at the Irkutskenergo Cogeneration Plant, JSC
The study is aimed at assessing the influence of the physical and chemical properties of coal burned at thermal power plants in the Irkutsk Region on the operational characteristics of boiler units. In order to forecast the application proccess for coal of the Mugunskoye and Irbeyskoye deposits in terms of fuel types not previously used at the PJSC Irkutskenergo thermal power plant, mathematical methods were used in the SAF software package developed by the authors on the basis of the Microsoft Excel. In analysing the mineral composition of the Irbeyskoye deposit coal, slagging of heating surfaces and superheaters (by the example of boiler units at the Novo-Irkutsk thermal power plant) as a result of its combustion in a temperature range above 900ºС is anticipated due to the high content (16.2%) of iron (III) oxides in the ash. In the SAF software package, indicators calculated for determining the slagging and polluting properties of solid fuels included a tendency to ferriferous, sulphate-calcium and active alkali-based depositing, slagging indices of the combustion chamber, pollution of boiler unit screens, etc. Recently-used new coal types of the Mugunskoye and Irbeyskoye deposits were revealed to have a high tendency to form ferriferous deposits equal to 0.683 and 0.678 p.u., respectively. In addition, the slagging index of the combustion chamber remains at a high level (above 0.75) during the combustion of the studied coals. It was proposed to equip the BKZ-420-140 boiler unit with more modern water soot-blowers with the commission of the full-time long-retracting soot-blowers for cleaning the superheater from ash deposits. The proposed measures ensure an increase in the service life of boiler heating surfaces by 2-3 times. In order to avoid emergency situations leading to unplanned shutdowns of boilers, the need for expert assessment of the slagging and polluting properties of fuels previously unpractised at thermal power plant is demonstrated.