Influence of Heat Exchanging Tubes on Local Heat Transfer Coefficient in Fluidized Bed Reactor

IF 1.3 4区工程技术 Q3 CHEMISTRY, ORGANIC Petroleum Chemistry Pub Date : 2024-05-23 DOI:10.1134/s0965544124010171

Wasan A. Mohsen, Basma A. Badday, Jamal M. Ali, Abbas J. Sultan, Zahraa W. Hasan

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Abstract

Fluidized bed reactors are widely used in a variety of chemical industrial processes for extremely exothermic reactions. But the performance of the reactor could be impacted if the exothermic reaction’s heat isn't removed sufficiently. Understanding and analyzing the heat transfer mechanisms occurring in the reactor is crucial to improving the reactor’s overall performance as well as the chemical process. The investigation was carried out in two stages) one tube heater, five internals equipped with one tube heater). In both stages, the heat transfer probe was moved to different places around and inside the center and the range of gas velocity was 0.2–0.48 m/s. A sophisticated heat transfer system was used to investigate locally and instantly how a bundle of vertical heat-exchanging tubes affects the heat transfer coefficient (HTC) in a gas solid fluidized bed. The experiments were conducted on 0.13 m inner diameter Plexiglas fluidized bed reactor by using silica sand as particles with size of 600 µm and fixed packing height 35 cm. The heating element consists of solid brass shell, a heater and flux sensor. The heat transfer probe dimensions 12 mm diameter and 8 cm length. The thermocouples were 10 cm above distributer. The local heat transfer coefficient (LHTC) increase with increasing fluidizing velocity. There is a different behavior of HTC at various local position of tube heater in comparison with other different tubes position. When there are vertical internals present in the center, the HTC increases by 31% for different gas velocities. A comparison of local heat transfer coefficient with internal tube and without internal tube gives a reasonable result.

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换热管对流化床反应器局部传热系数的影响

摘要流化床反应器广泛应用于各种化学工业过程中的极度放热反应。但是，如果放热反应的热量没有被充分带走，反应器的性能就会受到影响。了解和分析反应器中的传热机制对于改善反应器的整体性能和化学过程至关重要。调查分两个阶段进行（一个管式加热器，五个内部装有一个管式加热器）。在这两个阶段中，传热探头被移动到中心周围和内部的不同位置，气体速度范围为 0.2-0.48 m/s。实验中使用了一套复杂的传热系统，用于局部和即时研究垂直换热管束如何影响气固流化床中的传热系数（HTC）。实验在内径为 0.13 米的有机玻璃流化床反应器上进行，使用粒度为 600 微米的硅砂颗粒，填料高度固定为 35 厘米。加热元件由实心黄铜外壳、加热器和流量传感器组成。传热探头直径为 12 毫米，长度为 8 厘米。热电偶位于分布器上方 10 厘米处。局部传热系数（LHTC）随着流化速度的增加而增加。与其他不同位置的管子相比，管加热器不同位置的 HTC 表现不同。当中心存在垂直内管时，在不同的气体速度下，HTC 增加了 31%。有内管和无内管的局部传热系数比较得出了合理的结果。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Petroleum Chemistry 工程技术-工程：化工

CiteScore

2.50

自引率

21.40%

发文量

102

审稿时长

6-12 weeks

期刊介绍： Petroleum Chemistry (Neftekhimiya), founded in 1961, offers original papers on and reviews of theoretical and experimental studies concerned with current problems of petroleum chemistry and processing such as chemical composition of crude oils and natural gas liquids; petroleum refining (cracking, hydrocracking, and catalytic reforming); catalysts for petrochemical processes (hydrogenation, isomerization, oxidation, hydroformylation, etc.); activation and catalytic transformation of hydrocarbons and other components of petroleum, natural gas, and other complex organic mixtures; new petrochemicals including lubricants and additives; environmental problems; and information on scientific meetings relevant to these areas. Petroleum Chemistry publishes articles on these topics from members of the scientific community of the former Soviet Union.