Evaluation and Analysis of Coke Formation and Deposition in Coal-Liquefaction-Process Equipment

摘要

This study was made to develop correlations that may provide guidance in preventing or minimizing formation and deposition of coke or coke-like solids in coal liquefaction process equipment. Relevant published literature was reviewed to ascertain the current knowledge of the subject, as well as to extract and consolidate the data base that may be of use in accomplishing this goal. The information available from the literature was largely qualitative in nature, and most of it was not directly applicable. The only quantitative data base of practical use, although incomplete, was derived from progress reports of the Wilsonville Pilot Plant for the SRC-I fired slurry preheater. A comprehensive analysis of the Wilsonville preheater data based on several postulates and assumptions regarding the coking mechanism resulted in dimensional correlations of the given forms. The plots of these empirical correlations are within 95% confidence limits of most experimental coking data points, and the curves represent the incipient coking conditions. Examination of the plots shows that practically all the noncoking data points from runs made with Kentucky No. 9 coal are found in the regions below curves 1 and 2. Similarly, the noncoking data points from runs with Indiana V coal are located almost completely below curve 1; however, most of them fall in the region above curve 2. This apparent inconsistency may be at least partially attributable to the difference in the characteristics of the two types of coals and to incompleteness of the original plant data. Further efforts are required to resolve this inconsistency and to improve the coking correlations developed. These include acquisition of additional data from major coal liquefaction facilities and analysis of the data to broaden the bases for the correlations. (ERA citation 07:049046)