The development path of direct coal liquefaction system under carbon neutrality target: Coupling green hydrogen or CCUS technology

Abstract

Direct coal liquefaction can directly transform solid coal into high-end oil products with a conversion efficiency of nearly 60 %, but still emit a certain amount of CO2 during the oil production process. The carbon neutrality target places an urgent demand on its low/zero-carbon emissions and technology transformation. In this work, based on the analysis of the main carbon emissions in a traditional oil production system, carbon neutral technology-based direct coal liquefaction systems coupled with green hydrogen, green electricity, or CCUS technologies are proposed. The technical–economic characteristics, environmental impact, and influences of key parameters (e.g., coal/oil/photovoltaic electricity prices, carbon tax) for industrial-scale low/zero-carbon oil production systems are analyzed. Compared with the traditional system, the proposed systems coupled with CCUS technology for high and full concentration CO2 capture could have competitive advantages when the carbon tax prices are higher than 159.1 and 234.7 yuan/t CO2, respectively. When coupled with green hydrogen or green electricity, the cost of hydrogen or electricity storage will have an important impact on oil production profits and scheme selection. To achieve ∼zero carbon emissions, when the photovoltaic green electricity price is > 0.28, 0.07–0.28 and < 0.087 yuan/kWh (or energy storage breakthrough), the appropriate technical options are CCUS full carbon capture, CCUS capture of high concentration carbon with photovoltaic power generation, and photovoltaic green hydrogen with the photovoltaic electric boiler replacing coal-fired boiler, respectively. The research results could provide an important reference for the net-zero carbon emissions of the coal chemical industry under the carbon neutrality target.