Development of Magagement System of Deterioration of Heat Exchangers in Chemical Plants

为了对化工装置中的大量换热器进行管理，需要对换热器的总体换热系数进行估算。但是，存在以下问题。问题(1)由于测量变量误差大，总换热系数估计值不可靠。问题(2)由于缺少测量变量，无法得到总传热系数的估计值。对于问题(1)，我们证明了可以用数据调和的方法来补偿测量误差来估计总传热系数。对于问题(2)，我们建议即使不测量流量，也可以利用流量变化的时间来检测换热器的劣化。在此基础上，提出了对偏差较大的故障流量计进行在线检测的方法，以提高测量流量的可靠性。

In order to manage a lot of heat exchangers in chemical plants, it is necessary to estimate overall heat transfer coefficients of heat exchangers. But, there are the following problems.Problem(1)Estimated values of overall heat transfer coefficients are not reliable because of large errors of measured variables.Problem(2)Estimated values of overall heat tranfer coefficients are not obtained because of the shortage of measured bariables.As to the Problems(1), we show that overall heat transfer coefficients can be estimatred by applying the method of data reconciliation to the compensation of measured errors. With respect to the Ploblem(2), we suggest that the deterioration of heat exchanger can be detected by use of the timing of change of flow rates even if flow rates are not measured.Furthermore, we propose the on-line detection method of faulty flow meters that have large biases for the purpose of improvement of the reliability of measured flow rates.