电伴热布置方式对管内熔盐解冻过程的影响研究  

Study on the Effect of Electric Tracing Heater Arrangement on the Thawing Process of Molten Saltin Pipeline

作　　者：王佳明 黄静 曾柱楷 曾勇 徐顺塔 刘豪[2] WANG Jia-ming;HUANG Jing;ZENG Zhu-kai;ZENG Yong;XU Shun-ta;LIU Hao(Powerchina Zhongnan Engineering Corporation Limited, Changsha 410014, China;State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China)

机构地区：[1]中国电建集团中南勘测设计研究院有限公司,湖南长沙410014 [2]华中科技大学煤燃烧国家重点实验室,湖北武汉430074

出　　处：《节能技术》2022年第1期36-42,51,共8页Energy Conservation Technology

基　　金：中国电建集团重大专项课题“太阳能热发电设计、装备制造及施工建造系统集成技术”(DJ-ZDZX-2018-02)。

摘　　要：为揭示电伴热布置方式对熔盐冻堵管道解冻特性的影响,构建了电伴热熔盐管道二维模型并开展了熔盐解冻过程的模拟计算,探讨了电伴热根数、敷设面积和加热功率对水平管道内二元熔盐熔化过程的影响。研究结果表明:在保持总功率一定条件下,多根小面积电伴热代替单根大面积电伴热进行分散对称布置时,熔盐熔化过程的温度均匀性提升,熔盐完全熔化所需的时间减少;单位长度电伴热的圆周敷设弧长从10 mm扩大到188.4 mm,管内熔盐解冻过程中温度梯度降低了20.3%,同时熔盐完全熔化所需的时间缩短了20.6%。当管外壁均匀受热时,提高电伴热功率将缩短熔盐完全熔化所需的时间,但会增加熔化过程的温度不均匀性。基于上述分析,在实际熔盐管道的防凝保温以及解冻过程中,建议在管道外壁面均匀敷设电伴热加热元件或者采用具有均匀加热的伴热方式(如感应加热)以实现管内熔盐均匀且快速熔化。To reveal the effect of electric tracing heater arrangement on the thawing characteristic of a freezing molten salt pipe,a two-dimensional model of the molten salt pipe with electric tracing heaters is constructed,and the numerical simulation of the molten salt thawing process is carried out;the effect of the number,laying area,and heating power of the electric tracing heater on the melting process of binary molten salt in the horizontal pipe is explored.The results show that the temperature uniformity of the molten salt melting process is improved and the time required for complete melting of molten salt is reduced when multiple small-area electric heat tracers instead of a single large-area electric heat tracer are arranged symmetrically in the unchanged total power condition.As the laying arc length per unit length of the electric tracing heater is enlarged from 10 to 188.4 mm,the temperature gradient during the in-pipe molten salt thawing process is reduced by 20.3%while the time required for complete melting of molten salt is shortened by 20.6%.Under uniform heating for the pipe wall,increasing the power of the electric tracing heater shortens the time required for complete melting of the molten salt,but it enlarges the non-uniformity of the melting process.Based on the above analysis,in the anti-condensation and thawing process for molten salt pipes,laying the electric tracing heating element evenly on the outer wall of the pipe or using the uniformly tracing heating method(e.g.,induction heating)is suggested to achieve the uniform and rapid melting of molten salt in the pipe.

关 键 词：太阳能光热发电 二元熔盐 电伴热 解冻过程 均匀加热 瞬态模拟 

分 类 号：TK511[动力工程及工程热物理—热能工程]