Online Soft Measurement Of Beating Degree For Mid-consistency Refining

Paper industry is our country's traditional industry and it is closely related to the national economy. Pulp refining process plays an important part in papermaking process. Improving pulp quality and reducing consumption of energy make a tremendous difference to the development of paper industry. Compared with low consistency refining way, mid-consisten- cy refining way reduces the probability of the fiber to be cut, retains the fiber length and improves pulp quality. Especially to ZDPM Mid-consistency refiner, through analyzing parameters of beating process, the specific energy soft sensing model and BP ANN model are built.Firstly, the paper describes the engineering background of beating process, beating theory, attributes of pulp and soft sensing technology. And introduce the recent development of beating theory and soft sensing technology.Then analyze the main influencing factor of beating process and the measurement of these parameters. Mid-consistency refining process flow, methods of data acquisition and processing are introduced. The pulp concentration only can be measured off-line, so we fix the pulp concentration at 9%.When ZDPM Mid-consistency refiner operates smoothly, subpressure exits in the pulp inlet pipe. Deduce the maximum allowable pulp flow formula and explain why subpressure exits in pulp inlet pipe. Using polynomial fitting analyzes the relationship between pulp flow and subpressure of pulp inlet pipe.Analyze the useful part and useless part of ZDPM refiner beating power. The identifying method of net power and specific energy are discussed. The model based on net power and specific energy can be used to predict pulp beating degree.A three layer BP ANN model of beating degree is built, and the model is validated by experiment data.