Abstract:

Chemical looping technology is now limited by its insufficient fuel conversion and inefficient carbon capture. To solve such critical issues, a novel chemical-looping combustion (CLC) system for tower bubbling fluidized bed was designed. The whole loop system consisted of a tower fuel reactor (FR), an air reactor (AR), two loop-seals (LS), two cyclone separators, two risers and two down-comers. In cold model studies, methods of pressure measurement and outlet gas detection were applied to investigate the flow characteristics under different fluidization numbers, including pressure distribution, gas-solid distribution, solid circulation rate, and gas leakage. The results showed that the pressure balance in the system was guaranteed by the loop-seals. The FR fluidization number should be controlled between 3.5—4.0, which could guarantee a good gas-solid distribution in the FR, and lower the pressure loss between baffles. The solid circulation rate in the system was proportional to the pressure drop in the riser with a maximum of 0.013kg/s, and was mainly influenced by the fluidization number in reactors. The gas leakage from loop-seals to reactors was around 4%—8%, but there was no gas leakage between the FR and AR, which provided a good experimental basis for the design and operation of the thermal CLC system.

Key words: bubble tower, reactor, fluidized bed, chemical looping combustion, gas-solid flow, pressure measurement

摘要：

目前，化学链燃烧技术主要局限于不充分的燃料转化和低效的碳捕集率。为了解决这一问题，本文提出了一种基于多腔室塔式鼓泡床的化学链燃烧反应器系统。该系统由塔式燃料反应器、空气反应器、旋风分离器、返料器、提升管和下降管组成循环回路。采用压力测量和气体检测的方法，基于冷态模型研究在不同风量下该系统内的压力分布、气固分布、固体循环量以及窜气规律等气固流动特性。结果表明：返料器可以弥补两个反应器间存在的压差，保持系统内的压力平衡；燃料反应器内流化数应控制在3.5~4.0之间，在保证反应器内气固均匀分布的同时，减弱隔板处的压力损失；固体循环量与提升管内压降成正比，最高可达0.013kg/s，主要影响因素为反应器内流化数；返料器至反应器的窜气率为4%~8%，而两个反应器间几乎没有气体窜混，这为热态反应器的设计与运行提供了良好的实验基础。

关键词: 鼓泡塔, 反应器, 流化床, 化学链燃烧, 气固流动, 压力测量