Zhang Jie, You Changfu, Qi Haiying, Hou Bo, Chen Changhe, Xu Xuchang
Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084, China.
Environ Sci Technol. 2006 Jul 1;40(13):4300-5. doi: 10.1021/es052168w.
A moderate temperature dry desulfurization process at 600-800 degrees C was studied in a pilot-scale circulating fluidized bed flue gas desulfurization (CFB-FGD) experimental facility. The desulfurization efficiency was investigated for various operating parameters, such as bed temperature, CO2 concentration, and solids concentration. In addition, structural improvements in key parts of the CFB-FGD system, i.e., the cyclone separator and the distributor, were made to improve the desulfurization efficiency and flow resistance. The experimental results show that the desulfurization efficiency increased rapidly with increasing temperature above 600 degrees C due to enhanced gas diffusion and the shift of the equilibrium for the carbonate reaction. The sorbent sulfated gradually after quick carbonation of the sorbent with a long particle residence time necessary to realize a high desulfurization ratio. A reduced solids concentration in the bed reduced the particle residence time and the desulfurization efficiency. A single-stage cyclone separator produced no improvement in the desulfurization efficiency compared with a two-stage cyclone separator. Compared with a wind cap distributor, a large hole distributor reduced the flow resistance which reduced the desulfurization efficiency due to the reduced bed pressure drop and worsened bed fluidization. The desulfurization efficiency can be improved by increasing the collection efficiency of fine particles to prolong their residence time and by improving the solids concentration distribution to increase the gas-solid contact surface area.
在中试规模的循环流化床烟气脱硫（CFB-FGD）实验装置中，研究了600 - 800摄氏度的中温干法脱硫工艺。考察了各种运行参数对脱硫效率的影响，如床温、二氧化碳浓度和固体浓度。此外，对CFB-FGD系统的关键部件，即旋风分离器和分布器进行了结构改进，以提高脱硫效率和流动阻力。实验结果表明，由于气体扩散增强和碳酸盐反应平衡的移动，脱硫效率在600摄氏度以上随温度升高而迅速增加。在实现高脱硫率所需的长颗粒停留时间下，吸附剂快速碳酸化后逐渐被硫酸化。床层中固体浓度降低会缩短颗粒停留时间并降低脱硫效率。与两级旋风分离器相比，单级旋风分离器对脱硫效率没有改善。与风帽式分布器相比，大孔分布器降低了流动阻力，但由于床层压降降低和床层流化恶化，脱硫效率也降低了。通过提高细颗粒的收集效率以延长其停留时间，以及改善固体浓度分布以增加气固接触表面积，可以提高脱硫效率。
