Numerical analysis of various schemes for reconstructing the existing dust preparation system when changing the TР-100 steam generator operation from burning anthracite culm to burning gas coal

• Date: 2017
• Main Author: Rokhman, B.
• Format: Article
• Language: Russian
• Published: Institute of Renewable Energy National Academy of Sciences of Ukraine 2017
• Online Access: https://ve.org.ua/index.php/journal/article/view/47
• Journal Title: Vidnovluvana energetika

Three schemes for reconstructing the dust preparation system forthe boiler unit TP-100 for burning gas coal with respect to theexplosion safety of the dust system and the stability of the liquidslag leakage from the tap of the combustion chamber of thesteam generator at a wide load regulation range of 120-200 MWare studied. These schemes differ by the way of drying solidfuel. It is shown that at air drying of coal it is not possible toachieve a high level of explosion safety of the dust system evenwhen the standard temperature of the air mixture is within 70°C,nor the unloading of the block below 140 MW, which is lessthan the planned range of 120-200 MW, nor a large margin fordrying agent temperature by the condition of condensation ofwater vapor. The interval of the boiler load changing of the unitTP-100 using the gas-air drying scheme for coal is considerablynarrower than in the case of air drying. This is due to a decreasein gas temperatures at the outlet from the zone of maximum heatrelease and liquid slag, О2 concentration in the gas, and the burnoutefficiency of solid fuel due to the discharge of spent dryingagent loading with inert gases into the main burners. However,the degree of explosion safety of the dust system (О2 (byvolume) < 16%) and the temperature margin of the drying agentby the condition of water vapor condensation at air-gas drying ishigher than that of air one. Of the three proposed options forreconstructing the dust preparation system of the boiler unit TP-100, the most efficient is the scheme for drying coal with fluegases and discharging the drying agent into the cooled zone. Thisscheme allows to organize a regime of stable liquidл slagremoval within the planned interval of load regulation of theboiler unit TP-100 of 120-200 MW due to the followingmeasures: a) the thermal energy of the air is not consumed toevaporate the moisture of the raw coal; b) dry coal is fed to thezone of maximum heat release and inert gases are introducedinto it; c) a high degree purification from the dust in the spentdrying agent is provided. A high level of explosion safety of thedust system is achieved by a low oxygen content in the dryingagent (О2 < 10%). The proposed measures allow exceeding thetemperature of liquid slag above the temperature of normalliquid ash removal at 113°C, which is much higher than at the airand gas-air drying. This margin provides stable liquid