Experimental Study On The Fiber Fraction Of The Cylinder Hydrocyclone

Fractionation of softwood pulp fiber were carried out with a cylindrical hydrocyclone. The effects of feed rate and split ratio (overflow rate to feed rate ratio) on fractionation of pulp fiber are studied. Pulp fiber length characterization in different streams have been examined using FQA, and the fiber length fractionation density function f is calculated and the separation index H(L) is used to evaluate fiber fractionation performance for different streams. It is shown that, the split ratio is the most significant parameter for fiber fractionation performance and the fractionation performance is excellent with split ratio in the range between 0.12 and 0.16. There is a high proportion of fibers longer than the critical fiber length in the overflow stream, and there is a high proportion of fibers shorter than the critical fiber length in the underflow stream.Defining three new indexes-the overflow separation index M , the underflow separation index N and the total separation index F are used to evaluate fiber fractionation performance for different streams. It is shown that, the split ratio is the most significant parameter for fiber fractionation performance .But the effect of feed rate on fiber fractionation performance is weak..Results of M, N, F have show that , there is a high proportion of longer fiber in the overflow when M is higher , there is a high proportion of shorter fiber in the underflow when N is higher and there will be a good fiber fractionation performance when F is higher.