Causal analysis of process variability in dope preparation section of lyocell fiber manufacturing process and recommendations for improvement

Abstract

The primary objective of the project titled ‘Causal analysis of process variability in dope preparation section of Lyocell fiber manufacturing process and recommendations for improvement’ was to both quantitatively and qualitatively reduce the perturbations of the critical parameters of the process. The scope of the project revolved around the pulper and the Wiped Film Evaporator (WFE) / LIST section. The work done till date consists of two production division viz. 0.5 TPD and 10 TPD. The major parameter considered for study was Melt Flow Index (MFI) as this is one of the Critical to Quality parameters of dope. The factors directly/indirectly affecting MFI were studied and correlations were deduced. A sampling exercise was also conducted to determine certain properties of pulp, slurry and dope of 10 TPD section viz. Cp, Degree of Polymerization (DP), % Cellulose in slurry, dope and MFI of dope experimentally. The results obtained were analyzed and discussed in detail. Certain problems were observed in both 0.5 TPD and 10 TPD and recommendations to mitigate those have been proposed.