中压蒸汽流量测量密度补偿方式的误差分析

Error Analysis of Density Compensation Method for Medium Pressure Steam Flow Measurement

针对3.5MPa中压蒸汽管线中蒸汽计量的难题,对蒸汽流量测量过程中的温度、压力、密度补偿方法进行了综合分析;对过热蒸汽在0.10~5.00 MPa及310~450℃工况条件下的查表密度与3种拟合密度计算公式所得密度进行了误差分析,重点研究了工况条件在3.00~4.50MPa及390~430℃时过热蒸汽的计算密度与查表密度的误差值;以误差在0.1%~0.7%的最优拟合公式作为中压蒸汽DCS在线补偿计算公式,同时进一步确认了各个压力及温度区间所适用的密度拟合补偿公式。

Aiming at the difficult problem of steam metering in medium pressure steam of3.5 MPa,compensation method for temperature,pressure and density in steam flow measuring is comprehensively analyzed.Error analysis for the density obtained in look-up table and fitted with 3 calculation formulas respectively for the superheated steam under the condition of 0.10-5.0 MPa,and 310-450 ℃is conducted.The error value between the density in look-up table and calculated under the working condition of 3.0-4.5 MPa and 390-430 ℃ for the superheated steam is studied with emphasis.The best fitting formula with the error between 0.1% - 0.7% is selected as the DCS on-line compensation calculation formula for medium pressure steam.The density fitting compensation formulas suitable for different temperature and pressure intervals is further confirmed.