Analyses on Forms of Sulfurin Chinese Yanzhou Coal and Their Transformation during Pyrolysis by X-ray Absorption Spectroscopy

Abstract

In the processof pyrolysis, inherent and the added minerals are the main factors to affectthe transformation and distribution of sulfur in coal. In order to cleanly and efficiently use the inferior coal with high-sulfur content, Yanzhou coal containing 5wt % sulfur was chosen as the sample to do pyrolysis experiments in a fixed-bed reactor. The effect of iron additive on the sulfur forms and their transformation during coal pyrolysis wasstudied in this paper. Fe and S forms in raw coal with (FC) and without (RC) iron additive and their chars from different temperature were determined by XANES, and the gaseous products and total sulfur in char were also considered. The results show that addition of Fe in coal can make more sulfur retained in the char. The transformation of sulfur exists in the entire coal pyrolysis process from 200 to 1000 °C, and more inorganic sulfur was produced during the FC pyrolysis at high temperature (700–1000 °C). FeS existing in the FC char from 1000°C occupies about 62% of the total sulfur in char, but there is almost no FeS in the RC char at 1000 °C. The semi-quantitative analysis of XANES data by LCF fitting will also be discussed.