Response Characteristics Of Load Control Parameters In Supercritical And Subcritical Units

Supercritical unit load regulation, not only are lack of regulation of the relevantfactors in the analysis of quantitative relationships, but also mainly rely on operatingexperience.This paper, by seeking the relative deviation of the thermodynamic equations,obtains controllable factors such as temperature, pressure and flow impact for theload.And contacting both supercritical pressure and subcritical pressure boilers operatingdata, it compares the differences between the controllable factors affecting the load.Combined with supercritical and subcritical units operating data, through theanalysis of the formula, the results showed that In coal combustion systems, Forsupercritical unit loads greatest impact is the amount of air and coal; secondary air hasgreater impact, followed by the primary air. The result can be drawn coal combustionsystems for power regulation supercritical unit has a vital role but for subcritical units arenot.The main heating section about the impact of specific enthalpy increase is water walland super heater.Comparing the heat reheater and economizer with all the heat of theheaters, it shows the almost the same impact strength. The summary is concluded that theinfluence of inlet enthalpy on the exit of specific enthalpy this paragraph is greater thanthe impact of the enthalpy increase for exports.This paper analyzes the effects of the working status and convective heat transfer ofthe working fluid on the working fluid absorbing heat. When the fluid works in a differentstate, its pressure and temperature will have different impact strength in relative deviationof the enthalpy of the working fluid. Analyzed formulas to calculate the specific enthalpyof the working fluid in different areas, the reasons can be got that Supercritical workingfluids specific enthalpy changes more violently in the pseudo-critical temperature regions.Using the actual operating data, the results showed that fluctuations of working fluid onconvective heat transfer in the water wall and economizer is mainly affected by changes in the amount of working fluid flow, but it is affected relatively large by relative deviation oftemperature in superheater, reheater and spiral pipe.