Issues regarding the installation of steam tracing pipes
Thread Content
This post was last edited by jeave on 2020-7-31 at 16:08. I recently encountered a situation where, for the steam tracing pipes provided by the client, the tracing pipe in the bypass of the flow meter was directly taken from the tracing pipe of the main pipeline; it then rejoined after passing through the bypass, and the diameter of the pipe remained the same in both cases. I’m worried that there might be some issues with this approach, as I don’t fully understand it. I would appreciate it if experts could tell me whether this is a problem or not
It’s possible that the drawings describe it this way, but the actual construction on site is different. Dedicated installers will go through one route and then return via another, which is time-consuming and laborious ； If you want to be lazy, you can just take the side quest; in that case, close supervision on-site is necessary ； Otherwise, once the insulation layer is installed, nothing will be visible. In the initial stage of operation, steam flows through both lines; over time, the flow rate in the line with higher resistance decreases due to gradual blockage by debris inside the pipe.
This post was last edited by Shutong on 2020-7-31 at 18:08. Please have the original poster take a look at SHT 3126-2013, Code for Design of Heating and Insulation of Instruments and Pipelines in Petrochemical Industries, Section 5.3.2: The installation of steam heating systems shall comply with the following requirements: The heating steam should preferably be low-pressure superheated steam or low-pressure saturated steam; b) A separate steam supply system should be provided for heating instruments. For the few scattered instruments that require heating, steam can be supplied according to specific circumstances, as shown in Figure C of Appendix C; d) Each instrument that needs heating should be part of a separate heating circuit, and each such heating circuit should constitute an independent system. I believe that flow meters belong to the instrument system, while the steam heating system should have its own supply of steam; moreover, the bypass system used by the building owner is not isolated from the heating system for the flow meters. Other friends are also welcome to share their opinions
In a situation like the one shown above, where the flow meter itself is located on the pipeline, its heating system is integrated directly with the pipeline’s heating system and thus belongs to the pipeline system. If the flow meter is equipped with a pressure tapping system, then the heating for that pressure tapping circuit should be part of the instrumentation system. The advantage of this is that some of the on-site instruments can be directly heated within the pipeline system. Save costs. The method of using heat tracing shown in the diagram is not advisable; as mentioned on the second floor, it tends to cause blockages
In a situation like the one shown above, where the flow meter itself is located on the pipeline, its heating system is integrated directly with the pipeline’s heating system and thus belongs to the pipeline system. If the flow meter is equipped with a pressure tapping system, then the heating for that pressure tapping circuit should be part of the instrumentation system. The advantage of this is that some of the on-site instruments can be directly heated within the pipeline system. Save costs. The method of using heat tracing shown in the diagram is not advisable; as mentioned on the second floor, it tends to cause blockages
The drawing shows it this way, indicating that there is also steam tracing here
This requires practical operation to determine. The wiring method shown in the diagrams can lead to a situation where, in case of a failure in the main circuit and attempts are made to switch to the bypass circuit, it turns out that the bypass circuit has frozen due to a short circuit caused by steam heating, rendering it unusable. In projects involving a freezing point of 105°C, the solution is to install a stop valve on each of the steam pipes in both the main and bypass circuits. When starting up the heat pipe, the bypass heating valve is closed, allowing the main circuit to provide heating for smooth operation. Once the main circuit is functioning properly and can convey material continuously, the bypass heating valve is opened to keep the heat pipe ready for use. Close the main road heating valve; as long as there is continuous flow, freezing will not occur. Of course, the use of two heating valves is based on the adoption of a continuous production process. If it is intermittent, then an extra loop needs to be added in the bypass during on-site fabrication
This setup is incorrect; a single heat tracing tube should be used to provide heat tracing for these main pipes – no branches should be created, as otherwise the steam will take shortcuts.
No, if there is a location where the pressure difference between the two sides is small, stagnant water is likely to form on one side. One of the two pipelines is blocked, so it cannot provide heat tracing. The branch line should be supplied with water separately
No, if there is a location where the pressure difference between the two sides is small, stagnant water is likely to form on one side. One of the two pipelines is blocked, so it cannot provide heat tracing. The branch line should be supplied with water separately
No, if there is a location where the pressure difference between the two sides is small, stagnant water is likely to form on one side. One of the two pipelines is blocked, so it cannot provide heat tracing. The branch line should be supplied with water separately