Drainage of steam power pipelines

This post was last edited by Watt Energy Saving on 2019-6-21 at 11:33. Drainage design for steam mains – Zhong Yuyu from the Technical Department of Hangzhou Watt Energy Saving Engineering Co., Ltd. The latent heat contained in steam is released as a result of heat dissipation within the steam mains, turning it into condensed water. To effectively drain the generated condensate in a timely manner, condensate drainage pipes are generally installed every 30m to 50m along the steam delivery pipes, with steam traps used to discharge the condensate. Steam flows at high speed within the delivery pipes, and the condensate is not completely separated from the steam; as a result, it is difficult to collect and remove the condensate effectively. On the other hand, since the amount of condensate generated within the steam pipeline itself is low during stable operation, condensate discharge pipes with smaller diameters are generally used. This further makes it difficult for condensation water to accumulate. Under these circumstances, it is recommended to install a condensate collection tank. The condensate collection tank is connected to the main steam pipe in a T-shaped configuration, which enables effective collection of condensate and its discharge through steam traps. The experience of Watt Energy-saving’s steam engineers is that, when the diameter of the main pipe is less than 100 mm, it is generally recommended to use a collection tank with the same diameter ； When it exceeds 100 mm, the diameter of the water collection tank should be at least 1/2 of the main diameter. Also, be sure to install a discharge valve at the bottom of the water collection tank to remove impurities and the like, and place the condensate collection outlet at a position slightly higher than the bottom, thereby effectively protecting the steam trap. The diameter of steam main traps generally does not exceed 25 mm. Except for bimetallic traps which require a cooling tube, the rest of the traps should be installed as close as possible to the drain tank. The DT inverted barrel hydrostatic valve is the most suitable recommendation.

Steam power pipelines are primarily used in thermal power plants to transport steam and two-phase steam-water mixtures. Their characteristics include: a single type of fluid with well-defined properties, as well as high pressure and temperature. Under normal conditions, the steam used is high-pressure superheated steam, with pressures generally above 6.3 Mpa and temperatures above 400 degrees. Superheated steam usually has a low water content; therefore, when selecting steam traps, those designed for high temperature and pressure are preferred, and a large flow rate is not necessary. The most commonly used types are bimetallic and disc-type steam traps. In terms of cost, disc-type traps are cheaper, while bimetallic traps offer better energy efficiency and a longer service life.

During today’s discussion, the reviewer suggested not installing a steam trap, and instead using a dual-valve drainage system; the steam pressure should be 3.9 MPA, with the superheated steam temperature at 450°C

Is it a steam transmission pipeline from a power plant?

It is the steam produced by the waste heat boiler, which goes to the turbine

It is estimated that the auditor considered the pipeline to be short, and hydrophobic treatment was only necessary during start-up and shutdown, so a hydrophobic valve is not required

Check the power pipeline specifications; they contain recommended drainage solutions

Since it is double-valve hydrophobic and the steam is superheated, the moisture content is basically very low