Measuring Key Parameter Of Sugar Boiling Process Using Soft Sensor

Crystallization is the last step in the cane sugar processing. sugar crystallization with strongly nonlinearity and nonstationarity is a complicated physicochemical process. According to sugar refining technics, oversaturation of massecuite is the most prominence parameter of all ones, and it must be controlled to a certain degree during the process of whole crystallization. Because of its importance and its difficult measurement, in this paper a soft sensor is proposed to estimate it.After some variables which are related to oversaturation are analyzed on the base of second parameter principle of modeling soft sensor, temperature and brix are choosed to model soft sensor of massecuite oversaturation.When temperature keep a certain value, oversaturation is computed by Wright formula and brix can be obtained through computing the per cent of solid substance in the massecuite. By using least squares regression the soft sensor of oversaturation can be modeled. It can be seen from the simulation result, the relative error of oversaturation is too great at the critical saturation when oversaturation is computed by Wright formula compared with estimated by soft sensor. So in this paper, the whole process divided into two parts, and one is massecuite at undersaturation and the other is massecuite in saturation. soft sensors of these two parts can be obtained by using least squares regression.