System for routing preseparator drains

In a steam turbine system employing a moisture preseparator drain system for erosion-prevention of exhaust piping between the steam turbine exhausts and one or more moisture separator drain tanks, which drain system includes drain lines opening into a collection tank for collecting preseparator drain liquid removed from steam exiting the turbine exhausts, the collection tank being upstream of the moisture separator drain tank, a flash-preventing system for preseparator drain liquid exiting the collection tank, comprising:

• eductor means disposed between the collection tank and the moisture separator drain tank, for suctioning liquid from the collection tank;
• a source of motive fluid coupled to said eductor means, said motive fluid being at a lower temperature and a higher pressure than liquid in the collection tank;
• first pipe means for delivering liquid from the collection tank to said eductor means;
• second pipe means for delivering liquid discharged from said eductor means to the moisture separator drain tank;
• and
• control means for controlling flow of said motive fluid into said eductor.

In a steam turbine employing a moisture preseparator drain system for erosion-prevention of exhaust piping between the steam turbine exhausts and one or more moisture separator drain tanks, which drain system includes drain lines opening into a collection tank for collecting preseparator drain liquid removed from steam exiting the turbine exhausts, the collection tank being upstream of the moisture separator drain tanks, a flash-preventing system for preseparator drain liquid exiting the collection tank, comprising:

• eductor means disposed between the collection tank and the moisture separator drain tank, for suctioning liquid from the collection tank;
• a source of motive fluid coupled to the eductor means, said motive fluid being at lower temperature and higher pressure than the collection tank liquid;
• first pipe means for delivering the collection tank liquid from the collection tank to said eductor means;
• second pipe means for delivering liquid discharged from said eductor means to the moisture separator drain tank;
• control means for controlling flow of said motive fluid into said eductor means, said control means comprising a flow control valve and a liquid level sensor within the collection tank for controlling the flow control valve in response to the level of liquid within said collection tank such that the amount of flow of motive fluid into said eductor means varies with the level of liquid to be suctioned from the collection tank by said eductor means;
• spray means for spraying a cool liquid into the collection tank for precooling the preseparator drain liquid entering the collection tank;
• a source of cool liquid for said spray means;
• delivery means for delivering said cool liquid to said spray means;
• and
• submerged entry means for the drain lines entering into the collection tank, said first pipe means projecting upward within the collection tank so that liquid leaving the collection tank via said first pipe means exits at an elevation above that at which the drain lines enter the collection tank.