Troubleshooting shellandtube heat exchangers（故障排除管热交换器）.pdf

Troubleshooting shell-and-tube heat exchangers Use these techniques and guidelines to ensure more reliable heat transfer D. Gulley, Gulley Computer Associates, Tulsa, Fig. 1. Stratified flow pattern. Oklahoma t is stressful when exchangers go online and dont per­ 5. Have any warnings been ignored in the heat form as they should. But not all scary things go bump exchangers design? Iin the night. Heat exchangers that go onstream and 6. Was the advice on bundle-sealing devices followed? dont perform are also scary. This is especially true if 7. Ifthe problem is freezing or heat damage, could the there is a lack of thermal wells, pressure gages and temperatures in the clean condition be the problem? flowmeters. In addition, you are told that many hun­ In some cases, it is helpful to measure temperatures dreds of thousands of dollars a day are being lost due to on the exchangers exterior. This can identify unvented decreased production, so the problem has to be found gas, stratified flow or fluid bypassing. Ifthese tempera­ immediately. In many cases, there has to be a shutdown. tures are not too hot or cold, you can check the shell by Here is helpful information on finding a cure, including: feeling with your hands. • What information to collect and what to look for • The importance of calculated pressure drops and how Pressure drops. These are a big help in analyzing per­ they help analyze the problem formance problems. They also provide a rough check of • Two-phase flow emphasizing low heat transfer due flowrates. Single-phase streams should check reasonably to stratified flow