Study On The Intensity Of Sulfitation For Clarifying Process Of Sulfitation Method Sugar Factory By Soft-Sensing Theory

Guangxi Province is the biggest sugar base in China. The sugar industry is the pillar industry in Guangxi. Sulfitation method is the main method used in most of the sugar factory. The clarifying process is the most important process in the manufacturing process of sugar. This process affects directly the quality of the final product. Intensity of sulfitation is the key technical parameter in clarifying process. If it is too high, the degree of sulfur of the final product will be high and the final product will be poor quality, and if it is too low, that will affect the result of clarification. Due to lacking of effective on-line instrument to measure the intensity of sulfitation, manual sampling and iodometric titration is still the main method to measure the intensity of sulfitation at present. Because it will take a long time to finish testing, the operators can not timely take advantage of the change of intensity of sulfitation to regulate the technological parameters such as pH and so on, that will cause instability to quality of the final product.In order to solve this problem, the paper designs a virtual measuring instrument for intensity of sulfitation, which base on soft-sensing technology and a lot of off-line and on-line history data of clarifying process from a sugar factory in Guangxi. With the flow of sugarcane juice, the pH value of neutralization, preliming the pH value and limed valve position as auxiliary variables, then building models of the soft-sensing for intensity of sulfitation and researching on it. Several soft-sensing models are established respectively by Radial Basis Function neural network (RBFNN), BP neural network and Genetic Dynamic Fuzzy Neural Network (GDFNN). The result is that the performance of the first one is the best through the simulation of models and analyses of performance using MATLAB7.0.Then choosing the first one to use for researching later. Using VC++software to design the OPC client so as to get the stored data of clarifying process. A virtual instrument based on soft-sensing for intensity of sulfitation, man-machine interface and the on-line correction mechanism were designed in LabVIEW8.5.The soft measuring instrument designed in this paper can realize the following functions:preserving the historical data of auxiliary variables and intensity of sulfitation, measuring the intensity of sulfitation online, monitoring the working condition at laboratory and production field and the lab technicians give the feedback about the information of measuring error to operators so that operators can regulate the technological parameters in time. The instrument’s maximum relative error is5%; it meets basically the technical requirements of production.