Innovative Internally Circulating Reactor Concept for Chemical Looping-Based CO2 Capture Processes: Hydrodynamic Investigation

Simulation-Based Design and Economic Evaluation of a Novel Internally Circulating Fluidized Bed Reactor for Power Production with Integrated CO2 Capture

Limiting global temperature rise to well below 2 °C according to the Paris climate accord will require accelerated development, scale-up, and commercialization of innovative and environmentally friendly reactor concepts. Simulation-based design can play a central role in achieving this goal by decreasing the number of costly and time-consuming experimental scale-up steps. To illustrate this approach, a multiscale computational fluid dynamics (CFD) approach was utilized in this study to simulate a novel internally circulating fluidized bed reactor (ICR) for power production with integrated CO2 capture on an industrial scale. These simulations were made computationally feasible by using closures in a filtered two-fluid model (fTFM) to model the effects of important subgrid multiphase structures. The CFD simulations provided valuable insight regarding ICR behavior, predicting that CO2 capture efficiencies and purities above 95% can be achieved, and proposing a reasonable reactor size. The results from the reactor simulations were then used as input for an economic evaluation of an ICR-based natural gas combined cycle power plant. The economic performance results showed that the ICR plant can achieve a CO2 avoidance cost as low as $58/ton. Future work will investigate additional firing after the ICR to reach the high inlet temperatures of modern gas turbines.

The evaluation of a methane autothermal chemical looping reforming experiment based on exergy analysis

Compared with a double circulation fluidized bed, an internally circulating reactor (ICR) has a wider pressure range, thereby increasing the conversion efficiency of methane and reducing the cost. However, since the ICR is a new reactor, there is a lack of detailed analysis and research on the internal processes inside the reactor. Consequently, in this paper, a detailed exergy analysis and an advanced exergetic analysis are utilized to evaluate a methane autothermal chemical looping reforming experiment carried out on an ICR. A detailed analysis of the internal exergy destruction of the ICR is carried out by establishing a mathematical model for the enthalpy and exergy of the substance. The exergy destruction inside reactors is divided into the exergy destruction in the chemical reaction process, the destruction of thermal exergy and other flowing exergy destruction. The influences of the CH₄/NiO molar ratio and addition of steam or not on exergy destruction are studied. With the increase of CH₄/NiO molar ratio, the chemical looping reforming process gradually supersedes the chemical looping combustion process and becomes the dominating reaction, which exerts a strong beneficial influence on the reduction of exergy destruction of chemical reactions. When the CH₄/NiO molar ratio is 0.60, the exergy efficiency of the product is up to 52.17%. The advanced exergetic analysis provides a direction for improving the experiment. Based on these results, the ICR is evaluated in all aspects, including comparative evaluation, existing limitations, and possible future work.

Compared with a double circulation fluidized bed, an internally circulating reactor (ICR) has a wider pressure range, thereby increasing the conversion efficiency of methane and reducing the cost.