催化裂化装置衬里-金属复合结构非稳态热载传热研究

Study on heat transfer of composite lining-metal structure in unstable temperature field of FCCU

采用线性叠加原理研究高温压力容器衬里-金属复合结构在非稳态热载下的传热机理和规律。通过建立考虑多层传热的非线性有限元模型,研究了衬里-金属复合结构在非稳态温度载荷作用下的传热规律,讨论了锚固钉分布、衬里破坏程度及衬里隔热性能对结构温度分布的影响。研究表明:锚固钉密度越大,金属层温度越高,锚固钉周围温度场呈轴对称变梯度下降分布;金属层温度随衬里损坏程度的增大明显升高,损坏厚度比按0,20%,40%,60%和80%增大时,金属层温度升高幅度分别为8.0%,10.0%,13.1%和23.3%,损坏高度为96,288,480 mm时,金属层温度增加幅度依次为16.7%和5.71%;衬里材料当量导热系数与金属导热系数一致时达到复合结构温度极值,C02衬里在内集气室温度750℃、衬里损坏高度为288 mm、衬里损坏厚度80%时的温度极限为336℃。

The thermodynamic properties of composite lining-metal structure in unsteady temperature field of high-temperature vessel are simulated with principles of linear superposition. The heat transfer laws of lining-metal structure in unsteady temperature field are studied by establishment of multi-layer non-linear finite element model. The impacts of distribution of anchor nails,degree of lining damages and insulation performance of lining on temperature distribution of the structure are analyzed. The results show that,the temperature of metal layer rises with increasing density of anchor nails distribution; The temperature gradient has an accelerated decline around the nails and metal layer temperature rises with the expansion of lining damage area.When the damaged thickness is increased to 0,20%,40%,60% and 80%,the temperature of metal layer rises 8. 0%,10. 0%,13. 1% and 23. 3% respectively. When the damage height goes from 96 mm to 288 mm and to 480 mm,the metal layer temperature rises by 16. 7% and 5. 71% respectively. When the equivalent thermal conductivity of lining material is consistent with that of metal material and temperature limit is reached,the temperature of C02 lining in internal collection chamber is 750 ℃,the height of damaged lining is 288 mm,and the temperature limit of 80% lining thickness damage is 336 ℃. The study results in this paper are consistent with the domestic and international industry standards for pressure vessels with lining.