Abstract:

Semi-coke is major byproduct of oil shale retorting. Rationally using semi-coke is the basis of comprehensive utilization of oil shale. Semi-coke samples of oil shales in 3 Huadian ore fields were obtained from a retorting experimental table set up by the authors. The basic physicochemical characteristics of semi-cokes were investigated in detail by a variety of experimental methods. The mineral composition of semi-cokes was measured with XRD. Abundance and enriched characteristics of some trace elements in the semi-coke samples were analyzed by inductively coupled plasma atomic emission spectroscopy(ICP-AES). The combustion characteristics of semi-cokes were also measured using thermal gravitational analysis apparatus. In addition, properties of semi-cokes such as density, grindability, ash characteristics, specific heat capacity and thermal conductivity, etc were also investigated according to corresponding criteria respectively. It was shown that Huadian semi-cokes are a kind of low grade fuel with high ash, low calorific value and intermediate slagbonding trend. Huadian semi-cokes contain more calcite, quartz and illite-smectite mixed layer. Content of trace elements in the semicokes is relatively high and characterized by enriched As. Based on experimental results, related combustion kinetic models were proposed. It was considered that different reaction orders occur at different temperature during an combustion reaction of semi-cokes.

Key words: oil shale sime-coke, physicochemical characteristics, combustion, trace element, Huadian