General requirements for the layout of steam pipelines

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The steam pipes of general installations should be installed overhead, rather than in ducts, and certainly not buried underground. The main steam pipeline leading from the plant system to the equipment is generally located on the upper level of the pipe tray. Steam pipes shall be arranged in accordance with the following requirements: 1. Steam branch pipes shall branch off from the top of the main steam pipe, and the isolation valves on these branch pipes shall be installed on the horizontal section of the pipe close to the main pipe, in order to prevent liquid accumulation ； 2. A liquid separation vessel should be installed at the end of the main steam pipe ； 3. The spacing between demister units on horizontally installed steam main pipes is as follows: 1) Within the plant, it is advisable to set the spacing at 80 m for saturated steam and 160 m for superheated steam, with these units located at the lowest point of the steam main pipe as well as at its end ； 2) Outside the facility, it should be 300 m when going uphill, and 200 m when going downhill. 4. No branch pipes shall be connected from steam pipelines with strict steam usage requirements for other purposes ； 5. At the lowest point of the steam branch pipes, a drain valve or (and) a steam trap should be installed depending on the specific circumstances ； 6. No branch pipes shall be led from the ∏-type compensator on the steam pipeline. When branch pipes are led out from the straight sections near both sides of the ∏-type compensator, the branch pipes should not hinder the deformation or displacement of the main pipe. The displacement of the branch pipe outlet caused by thermal expansion of the Supervisor should not subject the branch pipe to excessive stress or excessive movement ； 7. Where a saturated steam main enters the plant, a steam trap should be installed near the boundary on the plant side, to drain the condensate generated during transportation through the trap’s drain. The superheated steam main enters the device; generally, no steam distributor is installed, but a drain valve is provided at the lowest point of the steam main ； 8. Multiple steam tracing pipes should be arranged in groups and equipped with distribution pipes; the steam for these distribution pipes should preferably be taken from the main pipe at a nearby location ； 9. For steam vent pipes that discharge directly into the atmosphere, the outlet should be at a height of no less than 2 meters. The discharge point should be located outside the main operational area, and a drain valve should be installed at the lowest point of such pipes; that is, a Φ6mm drain hole should be created near the elbow at the lower end of the pipe, with a DN15 pipe connected to it to lead the liquid to a suitable location such as a drain ditch or funnel. If a silencer is installed on the vent pipe, a DN15 drain pipe should be provided at the bottom of the silencer and connected to the vent pipe. The vent pipe should be equipped with guiding and load-bearing supports. 10. Strainers must be installed before the pressure relief valve and the control valve in saturated steam systems.