Abstract The design of an efficient and scale-up ready reactor system is, together with development of a high performance oxygen carrier, one of the most important research topics in chemical looping combustion. The dual circulating fluidized bed (DCFB) concept is a reactor concept consisting of two interconnected circulating fluidized beds, air and fuel reactor, where the oxygen carrier is the bed material. In the present study a so-called cold flow model is used to investigate the fluid dynamic behavior of a next scale design based on the DCFB concept (10 MW fuel power input) in order to optimize the system design. Four different designs of the fuel reactor are investigated with focus on the solid distribution and general operating parameters and their influence on the operating range. For that purpose, several parameters like e.g. the amount of fluidization gas for both reactors, the total solid inventory, and the fuel power, are variated. Pressure profiles are used to get a comprehensive overview of the fluid dynamic behavior of the different reactor designs. Comparison of the fuel reactor designs shows that operation of the air reactor is not affected by changes of the fuel reactor design. In contrast significant changes, especially in the solid distribution, are recognizable for the different fuel reactor designs. These changes concern mainly the adapted sections of the fuel reactor. Two of the proposed fuel reactor designs are limited in their operating range due to unstable operating conditions, caused by fluid dynamic effects. At such unstable operating conditions the solid inventory distribution between both reactors fluctuates. This behavior is caused by the geometry of the fuel reactor. Further, due to variations in the geometry of the fuel reactor effects leading to the unstable operating conditions are identified. However, unstable operating conditions are caused by the shape of the conical form of the bottom part of the fuel reactor.

中文翻译：

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用于气体燃料化学循环燃烧的 10 MW 规模反应器设计的流体动力学评估

摘要 设计高效、可放大的反应器系统，以及高性能载氧体的开发，是化学循环燃烧中最重要的研究课题之一。双循环流化床 (DCFB) 概念是一种反应器概念，由两个相互连接的循环流化床、空气和燃料反应器组成，其中氧载体是床层材料。在本研究中，使用所谓的冷流模型来研究基于 DCFB 概念（10 MW 燃料功率输入）的下一个规模设计的流体动力学行为，以优化系统设计。研究了燃料反应器的四种不同设计，重点是固体分布和一般操作参数及其对操作范围的影响。为此，几个参数，例如 两个反应器的流化气体量、总固体存量和燃料功率是不同的。压力曲线用于全面了解不同反应器设计的流体动力学行为。燃料反应堆设计的比较表明，空气反应堆的运行不受燃料反应堆设计变化的影响。相比之下，不同燃料反应堆设计的显着变化，尤其是固体分布的变化是可以识别的。这些变化主要涉及燃料反应堆的改装部分。由于流体动力效应引起的不稳定运行条件，两个提议的燃料反应堆设计在其运行范围内受到限制。在这种不稳定的操作条件下，两个反应器之间的固体库存分布会波动。这种行为是由燃料反应堆的几何形状引起的。此外，由于燃料反应堆几何形状的变化导致不稳定的操作条件被识别。然而，不稳定的操作条件是由燃料反应器底部的圆锥形形状引起的。