Evaluation of Energy Integration Aspects for Advanced Chemical Looping Systems Applied for Energy Vectors Poly-generation

Developing advanced conversion ways for fossil fuels and renewable energy sources to electricity or other total or partial decarbonised energy vectors (e.g. hydrogen, heat, synthetic fuels) is of paramount importance in modern energy sector. In addition, the development of carbon capture, utilisation and storage (CCUS) technologies is equally important for transition to low carbon economy. This paper evaluates various integration aspects of energy vectors poly-generation (focussing on power, hydrogen and synthetic fuels) based on chemical looping systems using syngas produced from solid fuel gasification. As illustrative examples, iron-based and calcium-based chemical looping systems were assessed in conjunction with coal gasification plants. The paper presents in details the evaluated plant configurations, focussing especially on operational and mass & energy integration issues. The plant designs were modelled and simulated using process flow modelling software, the results being used to assess the overall performance indicators. For energy integration analysis, pinch method was used to evaluate in details and to find the best energy integration options of available heat generated in the chemical looping unit into overall steam cycle of the power block. Other mass and energy integration aspects, e.g. air flow mass integration between the air separation unit and the gas turbine, plant flexibility in terms of changing generated energy vectors vs. time, were evaluated as well to assess their influence on overall plant energy efficiency. As the results show, the chemical looping-based conversion systems exhibit both higher energy efficiency and carbon capture rate than current state of the art gasification plants with gas-liquid absorption for carbon capture (benchmark case).