The main steam piping from the boiler superheater outlet to the main steam valve of the turbine should be equipped with drain pipes at all low points. If the main steam piping is divided into multiple branches and connected to the turbine, each branch and the main pipeline should be fitted with drain points.
The drainage system on the main steam piping is designed to promptly remove condensate from the pipes and accelerate startup speed after shutdown. Typically, the main steam piping has three drainage points, one at the end of the main steam trunk near the branch, and the other two before the branch piping of the steam turbine's main steam valve.
A pneumatic trap with the same diameter as the pipeline is installed on the drainage pipe, without any other valves. The outlet pipe of the trap has a larger diameter than the inlet pipe, and the pneumatic trap is designed for open air loss. Each drainage pipe is separately connected to a condensate expansion vessel.
High Temperature Superheated Steam Pipe Drainage System
The high-temperature reheated steam piping from the outlet of the boiler reheater header to the medium-pressure main steam valve of the turbine should have drain points at all low points. The drain tanks should be installed on the high-temperature reheated steam branch pipes near the turbine main valve, and no water level regulating device should be provided for the drain tanks.
In the high-temperature reheated steam piping condensate system, on one hand, the condensate system should promptly discharge the condensed water from the reheated steam piping; on the other hand, during the start-up of the heating piping, particularly during the hot start-up period, to accelerate the heating of the piping, the condensate system should also promptly remove it. Timely discharge of natural gas piping, condensate water, and cold steam.
