Techno-economic analysis of coal to liquids based on direct coal liquefaction technology

Direct coal liquefaction (DCL) is the conversion of coal in which coal is transformed into liquid hydrocarbon-based fuels through chemical reactions at elevated pressures and temperatures without being gasified to form syngas. The main objective of this paper is to carry out a comprehensive thermodynamic and economic evaluation for the DCL process based on the two primary conversion options under consideration: (a) Catalytic Coal Liquefaction (CCL) - the use of non-donor solvents with added hydrogen pressure; (b) Thermal Coal Liquefaction (TCL) - the use of solvents with some H-donor properties without hydrogen pressure and catalysts in the coal liquefaction reactor. For this purpose, steady-state process models for the DCL process are developed. The process modules address only the primary DCL processes and do not include any upgrading to transport fuels and chemicals as this will be conducted at refinery facilities by co-processing with petroleum fractions. To better understand the technical parameters and benefits of each scenario, a technical analysis has been conducted using the ECLIPSE modelling software. The overall cost estimation is carried out based on the cost of individual modules. The economic viability of catalytic and thermal direct coal liquefactions is also analysed in the paper.
Technical results showed that the oil yields (light and middle distillates) were around 998 barrels per day from the CCL process and 702 barrels per day from the TCL process when the feed rate of Brown Coal was 256 tonnes per day (on dry and ash free basis). Based on economic assumptions the light and middle distillate price would be €54.2/barrel with the CCL technology and €59.9/barrel with the TCL technology.