Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Tsinghua University,Beijing　 100084,China

液态金属气化技术是一种清洁的气化技术。因其原料适应性广,反应系统架构简单,适用于以固体碳为基础的分布式能源供给。反应过程中空气中的氧元素与熔融态的金属床料反应生成金属氧化物,再由碳原料还原氧化物生产含CO的产品气。为提高产品气中CO的比例,系统中引入了氧化锌（ZnO）以促进CO的生成。程序控温气化反应测试结果表明,氧元素由氧化锌向碳的迁移过程是气化反应的控制步骤,拓展熔池内部氧元素迁移路径,强化氧元素由氧化锌向碳的迁移过程是提高液态金属气化速率的重要途径。碱金属碳酸盐（Na2CO3,K2CO3）在高温下形成熔融态的氧传导路径,使得由氧化锌到碳原料的氧传导得到增强,改善了煤气化的反应特性。对不同碱金属碳酸盐的实验结果表明,具有较高氧离子传导率的碳酸盐能够使得熔体具有更好的煤气化特性。采用两种碳酸盐混合物制成的低熔点碳酸盐体系能够在较低温度（约720℃）时发挥氧离子传导的作用,促进气化反应在低温状态下的发生。

Liquid metal gasification is a clean energy technology to convert solid carbon material into gaseous fuels. Be- cause of its capability to convert various types of fuels,the air separation sub-system is no longer required. Liquid met- al gasification is a promising technology to fulfill the demand of distributed gaseous fuel supplement. During its opera- tion,liquid metal in the gasifier is oxidized to metal oxide,and then carbon material (e. g. coal,coke,biomass,munici- pal waste etc. ) is fed to the gasifier to reduce the metal oxide and produce CO rich gas. In order to increase the CO content in product gas,the oxide of active metal such as zinc oxide ( ZnO) is introduced into gasifier to promote CO production rate. The temperature programmed experiments in the present study have shown that the oxygen transfer from zinc oxide to carbon is rate determining step in the whole gasification process. Therefore,alkaline metal carbonate is introduced into the system to accelerate the oxygen ion transfer inside bed material. The alkaline metal carbonate melts at a given temperature,and builds oxygen ion transport pathways between zinc oxide and carbon. In the present study,sodium carbonate ( Na2 CO3 ) and potassium carbonate ( K2 CO3 ) were tested and Na2 CO3 ,as one process a higher oxygen ion conductivity achieved a higher gasification performance than Na2 CO3 did. A mixture made of Na2 CO3 and K2 CO3 ,which possess a melting point of nearly 720 ℃ ,was also tested in the present study,and by melt- ing and building oxygen transport pathways in bed material,carbon gasification reaction was triggered at a lower temperature.

国家自然科学基金资助项目(51476092)；

Cao Tianyu,Zhang Gepei,Shi Yixiang,et al. Experimental study of Zn-Sn based liquid metal carbon gasification[J]. Journal of China Coal Society,2016,41(10):2490-2494.