Design principles for steam pipelines

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The steam pipes of the device 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: a) Steam branch pipes shall emerge from the top of the main pipe, and the isolation valves on these branch pipes shall be installed on the horizontal section of the main pipe to prevent liquid accumulation. b) Drainage facilities shall be provided upstream of the isolation valve at the point where the steam main enters the plant boundary area, as well as at the end of the main. Drainage facilities should be equipped with drain valves, liquid separation tanks, and steam traps depending on the specific conditions. c) The spacing of drainage facilities on horizontally installed main steam pipes should meet the following requirements: 1) Within the plant, the distance for saturated steam should not exceed 80 m, and that for superheated steam should not exceed 160 m ； 　2) Outside the device, it should not exceed 300m when going uphill, and should not exceed 200m when going downhill. d) No branch pipes shall be connected from steam pipelines with strict gas usage requirements for other purposes. e) At the lowest point of the steam branch, a drain valve or (and) a steam trap should be installed depending on the specific circumstances. f) No branch pipes shall be taken off from the Π-type compensators on steam pipelines. When branch pipes are led out from the straight sections near both sides of the Π-type compensator, the branch pipes should not hinder the displacement of the main pipe. The displacement of the branch outlet due to thermal expansion of the Supervisor should not subject the branch to excessive stress. g) Where a saturated steam main enters the unit, a steam trap should be installed near the boundary on the unit side, with regular drainage measures in place below the trap. A steam distributor is generally not required for the main superheated steam pipe entering the unit. h) Multiple steam tracing pipes shall be arranged in groups and equipped with a distribution pipe; the steam for the distribution pipe should be drawn from the main pipe in close proximity. i) For steam vent pipes that discharge directly into the atmosphere, a drainage hole with a diameter of Φ6mm to Φ10mm should be provided near the elbow at the lower end of such pipes, and this hole should lead to a safe location. j) For waste steam pipes with continuous or frequent discharge, the discharge outlets should be located away from the operation area.