Techno-economic evaluation of coal-to-liquids (CTL) plants with carbon capture and sequestration

Coal-to-liquids (CTL) processes that generate synthetic liquid fuels from coal are of increasing interest in light of the substantial rise in world oil prices in recent years. A major concern, however, is the large emissions of CO2 from the process, which would add to the burden of atmospheric greenhouse gases. To assess the options, impacts and costs of controlling CO2 emissions from a CTL plant, a comprehensive techno-economic assessment model of CTL plants has been developed, capable of incorporating technology options for carbon capture and storage (CCS). The model was used to study the performance and cost of a liquids-only plant as well as a co-production plant, which produces both liquids and electricity. The effect of uncertainty and variability of key parameters on the cost of liquids production was quantified, as were the effects of alternative carbon constraints such as choice of CCS technology and the effective price (or tax) on CO2 emissions imposed by a climate regulatory policy. The efficiency and CO2 emissions from a co-production plant also were compared to the separate production of liquid fuels and electricity. The results for a 50,000 barrels/day case study plant are presented.

Research highlights
► Coal-to-liquids. Plants (liquids-only and co-production configurations) using bituminous coal are modeled for performance and cost.
► Liquids-only. Plants are thermodynamically more efficient than co-production plants.
► Co-production plants produce cheaper liquid fuels when the co-product electricity is sold to grid at current market prices.
► Carbon constraints have an effect on the performance and cost of the plant.