Steam Surface Condenser Question & Answers
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The two main devices that are used to vent the noncondensable gases are Steam Jet Air Ejectors and Liquid Ring Vacuum Pumps. Steam Jet Air Ejectors use high-pressure motive steam to evacuate the noncondensables from the condenser (Jet Pump). Liquid Ring Vacuum Pumps use a liquid compressant to compress the evacuated noncondensables and then discharges them to the atmosphere. To aid in the removal of the noncondensable gases, condensers are equipped with an Air-Cooler section. The Air Cooler section of the condenser consists of a quantity of tubes that are baffled to collect the noncondensables. Cooling of the noncondensables reduces their volume and the required size of the air removal equipment. Air removal equipment must operate in two modes: hogging and holding. Prior to admitting exhaust steam to a condenser, all the noncondensables must be vented from the condenser. In hogging mode, large volumes of air are quickly removed from the condenser in order to reduce the condenser pressure from atmospheric to a predetermined level. Once the desired pressure is achieved, the air removal system can be operated in holding mode to remove all noncondensable gases.


Steam surface condensers can be broadly categorized by the orientation of the steam turbine exhaust to the condenser. Most common are side and down exhaust. In a side exhaust condenser, the condenser and turbine are installed adjacent to each other, and the steam from the turbine enters from the side of the condenser. In a down exhaust condenser, the steam from the turbine enters from the top of the condenser and the turbine is mounted on a foundation above the condenser. Condensers can be further delineated by the configuration of the shell and tube sides.
The tubeside of a steam surface condenser can be classified by the following:
Number of tubeside passes
Configuration of the tube bundle and waterboxes
Most steam surface condensers have either one or multiple tubeside passes. The number of passes is defined as how many times circulating water travels the length of the condenser inside the tubes. Condensers with a once-through circulating water system are often one pass. Multiple pass condensers are typically used with closed-loop systems. The tubeside may also be classified as divided or non-divided. In a divided condenser, the tube bundle and waterboxes are divided into sections. One or more sections of the tube bundle may be in operation while others are not. This allows maintenance of sections of the tubeside while the condenser is operating. In a non-divided tubeside, all the tubes are in operation at all times.
Shell side
The shell side of a steam surface condenser can be classified by its geometry. Examples of types are:


What is a Steam Condenser?

An appliance designed for removing the back pressure upon a Steam Turbine

How is this accomplished?

Cooling the exhaust steam and converting it to water.

Why is reducing the back pressure so important on a steam turbine?

To increase Steam Turbine efficiency and obtain better economy.

Why is reducing the back pressure so important on a steam turbine?

It increases turbine efficiency.


What is a vacuum?

Space devoid of matter, a space in which the pressure is zero absolute.

What auxiliary must be connected to a condenser to make it work?

An air pump or air ejector.

What creates the vacuum in the condenser?

It should be understood, that the air ejector does not create the vacuum but it only maintains it.

How is vacuum measured?

In inches of mercury.

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