Study of TGM-94 boiler with variable feed water temperature using a calculation model

Abstract

The article substantiates the need to test performance capability and effectiveness of a steam boiler in the new conditions under any changes in the regenerative heating circuit of the feed water in a steam turbine plant. Such changes may include: the displacement of steam extractions onto high pressure feed water heaters by the sun, by heat from biomass or garbage burning, or by steam from third-party sources. For this purpose we have developed a mathematical model of the steam boiler TGM-94 from steam turbine installation K-150-130. The model was created with Boiler Designer program. Verification of the calculated and experimental data provided by Krasnodar TTP showed sufficient convergence in both the steam-water and gas paths. We observed differences in the following temperatures: feed water temperature after the first stage of the economizer, flue gases and air temperature at the inlet to the furnace. The maximum difference between calculation and experiment here is 6 °C. We studied the boiler operation at a variable load, but with a constant temperature of the feed water equal to the nominal value of 230 °C. It was shown that in order to work in this mode, and in order to maintain the superheat temperature of the primary and secondary steam, it is necessary to turn on the flue gas recirculation smoke exhausters. We studied the operation of the boiler at a reduced feed water temperature. It turned out that such work leads to a decrease in steam production, if we keep the fuel consumption unchanged. In the case of sustaining steam production, it is required to assess the temperature state of the heating surfaces additionally due to a significant increase in the superheat temperature of both the primary and secondary steam.