加氢装置用双壳程换热器的结构设计、制造及工程应用

THE STRUCTURE DESIGN,FABRICATION AND ENGINEERING APPLICATION OF DOUBLE SHELL SIDE HEAT EXCHANGER FOR HYDROGENATED UNIT

加氢装置用双壳程换热器分为法兰式和螺纹锁紧环式两种。双壳程换热器是在壳程筒体内设置一个纵向隔板 ,隔板穿过管束中心 ,将管束和壳程分为对称的两部分。从而实现了“纯逆流” ,使温差校正系数接近于 1,并使壳程介质的流速大大提高 ,因此提高了总传热系数及换热效率。对于壳程成为控制热阻的一侧且介质流速低 ,需强化壳程传热或壳程可利用压降较大或温差校正系数较小 ,需提高有效温差或需要减少换热器台数等场合 ,应优先选用双壳程换热器。但双壳程换热器制造工艺复杂 。

The double shell side heat exchanger for use in hydrogenated unit is divided into two kinds of flange type and thread lock ring type.Double shell side heat exchanger is put a longitudinal baffle in the shell of shell side.The baffle goes across the bundle center,and makes the bundle and shell side divided into symmetrical parts,and realize the 'pure reverse flow',and the correction factor is approaching to 1.The flow veloccity of shell side medium increases greatly.Then,the overall heat transfer coefficient is raised and the heat transfer efficiency is increased.The double shell side heat exchanger should be given priority to selection for that situation,such as,the shell side is the side to control heat resistant and the heat transfer of shell side should be strengthen;the useful pressure drop is relatively large,or the temperature difference correction factor is relatively small,and the temperature difference needs to increased; or the quantity of heat exchanger should be decreased.But the fabrication process of double shell heat exchanger is complicated,the first investment is fairly large.