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上流式反应器内构件设计及流动和返混特性
王威杰
Subtype硕士
Thesis Advisor雍玉梅
2018-07
Degree Grantor中国科学院研究生院
Degree Name硕士
Degree Discipline化学工程
Keyword上流式反应器,渣油加氢,内构件,流体动力学,返混
Abstract

上流式反应器是一种新型的渣油加氢反应器,采用气、液并流向上的进料方式流经催化剂床层,催化剂颗粒在床层内呈“微膨胀”状态。与工业上常用的固定床(如滴流床)渣油加氢反应器相比,此类反应器具有原料适用广、减缓床层压降、延长运转周期等优点。但在实际渣油加氢工业应用中仍存在一些问题,如床层局部飞温、热点出现、结焦生炭等,而解决这些问题最直接有效的方法是增置或改进反应器的内构件。因此,对上流式反应器内构件进行深入研究,设计出能解决上述问题的新型内构件,对科学研究和工业应用都具有重要的意义。本文在直径为300 mm的上流式反应器冷态实验装置上,用空气模拟气相、用水模拟渣油,用3种不同粒径和2种不同密度的氧化铝球形工业催化剂颗粒为填充颗粒,在表观气速范围为1.24×10-2 m·s-1~3.63×10-1 m·s-1、表观液速范围为9.48×10-4 m·s-1~5.96×10-3 m·s-1、装填高径比(H/D)范围为1.5~4.0、床层膨胀率φ≤5.0%的条件下,考察了不同模拟物系的颗粒粒径、颗粒密度、液相黏度、不同床层的高径比和不同操作条件以及内构件对上流式反应器内床层压降、气含率、持液量和床层轴向返混的影响规律。主要结论如下:(1)填充颗粒粒径为3.0 mm、4.5 mm和6.0 mm时,床层压降均随着表观气速、液速的增大而增大;床层压降随颗粒密度和液相黏度的增大而增大,随填充颗粒粒径的增大而减小;反应器内增置内构件的床层压降,比未加内构件的床层压降小。得到了计算压降的关联式。(2)气含率随表观气速、液速的增大而增大;填充颗粒粒径越大对应的气含率越大。获得了计算气含率的关联式。(3)床层中持液量随着表观气速的增大而减小,随着表观液速的增加而增大;填充颗粒粒径越大对应的床层持液量越小。获得了计算持液量的关联式。(4)随着表观气速、颗粒密度和高径比增大,对应的Pe数减小,返混加重;而随着表观液速和颗粒粒径的增加,对应的Pe数增大,返混减弱;在反应器内增置内构件比未加内构件的Pe数大,说明内构件可以减弱床层轴向返混。获得了计算Pe数的关联式。(5)通过床层压降、平均停留时间和Pe数等三个评价参数综合对比,得到内构件的最佳开孔率为0.125,反应器内最适宜增置内构件的位置是450 mm;对所设计的五种内构件性能进行对比,其中V型内构件的性能最优。;The up-flow reactor is a new type of hydrogenation reactor for residual oil, in which gas and liquid flow concurrently upwards through the catalytic bed, which shows "slight expansion". It has some advantages over the fixed-bed (such as trickle bed) reactor commonly used in the residual oil hydrogenation operation, such as wide range of feed residual oils, slowdown of bed pressure drop increase and prolonged operation cycle. However, there are still some operating problems, such as local temperature jump, hot spots, coking, etc. to be resolved. The most direct and effective way is to install proper internals inside the reactor. Therefore, in this work, novel internals are designed to solve the above problems and evaluated based on the measurements of characteristics of flow and back-mixing in the up-flow reactor. Such exploration is thought significant for both academic research and industrial application. In this thesis, an up-flow reactor with diameter of 300 mm was built up for cold model tests. Air and water are used to simulating gas and residue oil. Packed particles are the spherical alumina catalyst particles of three different sizes and two densities. The superficial gas velocity ranges from 1.24×10-2 m·s-1 to 3.63×10-1 m·s-1, the superficial liquid velocity is in the range of 9.48×10-4 m·s-1 to 5.96×10-3 m·s-1, the height-to-diameter ratio (H/D) of the bed is between 1.5 and 4.0, and the bed expansion rate is less than 5.0 %. The effects of these factors, especially the internal components, on the bed pressure drop, gas holdup, liquid holdup and axial backmixing were explored. The main conclusions are as follows: (1) The total pressure drop of the bed packed by 3.0 mm, 4.5 mm or 6.0 mm particles increases with the increase of superficial gas and liquid velocity, particle density and liquid viscosity, while the total pressure drop decreases with the increase of the size of packing particles. The total pressure drop of the bed with a new designed internal is lower than that of the reactor without an internal. The correlation of the total pressure drop of an up-flow reactor with an internal is obtained. (2) The gas holdup increases with the increase of superficial gas velocity and liquid velocity. The larger the size of packing particles is, the larger the gas holdup. (3) The liquid holdup decreases with the increase of superficial gas velocity and increases with the increase of superficial liquid velocity. The larger the size of packing particles, the smaller the liquid holdup. (4) The Peclet number decreases with the increase of the superficial gas velocity, particle density and the height-to-diameter ratio, so the bed axial backmixing is intensified. On the contrary, the Peclet number increases when the superficial liquid velocity and particle size become larger. The Peclet number in the reactor with an internal is smaller than that of the reactor without the internal, which means that the internal can strengthen the axial back-mixing in the bed. The Peclet number with an internal is obtained based on the measurements. (5) Based on the comprehensive comparison of three evaluation criteria: bed pressure drop, average residence time and Peclet number, the best opening percentage of the internal is 0.125, and its most suitable installation height is 450 mm. Internal V is the best choice among five internals tested. 

Language中文
Document Type学位论文
Identifierhttp://ir.ipe.ac.cn/handle/122111/26869
Collection中国科学院过程工程研究所
研究所(批量导入)
Recommended Citation
GB/T 7714
王威杰. 上流式反应器内构件设计及流动和返混特性[D]. 中国科学院研究生院,2018.
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