一种汽轮机组排汽焓和最优初压在线计算方法

A flexible on-line monitoring method of the exhaust steam dryness in steam turbine

通过对已往的汽轮机变工况计算方法的分析,提出了以汽轮机末级抽汽或次末级抽汽(过热蒸汽状态)为计算起点的汽轮机顺序变工况核算方法。根据初始假定的末级流量和现场实际的末级前热力状态和背压,用汽轮机变工况流型判别准则,判别级的流型,然后从末级前参数开始顺序进行一次级的变工况核算,得到新的排汽焓,最后算得机组热耗率和排汽焓。以此方法为变工况计算的基础,并利用系统分析方法,建立了在线确定单元机组最优运行初压的数学模型。为火电机组的优化运行提出了一种新思路。

Based on the analyses of those existed calculation methods for turbine varying condition, the paper gives a sequential varying condition calculation that starts with steam extraction of the final stage or the second final stage （ superheated steam condition）. According to the initially assumed final stage flow, the thermodynamic parameters before the final stage, and the backpres.sure, the flow patterns of the stage can be distinguished by a discrimination criterion of varying condition, then a stage varying condition calculation can be conducted in sequence from the front parameter of the final stage, so the new exhaust steam enthalpy and the exhaust steam dryness can be got, and the precise heat consumption rate and the exhaust enthalpy （or the dryness） of the steam turbine can be got easily. Obviously, without measuring the flow or the exhaust steam dryne.ss, the heat consumption rate and the dryness of the units can be monitored on line relatively accurate.