Steam Jet Air Ejectors by Mazda Limited

The two types of Steam Jet Air Ejector (SJAE) systems used in the industry to remove non-condensables and water vapor from main condensers. These power systems have found wide acceptance in modern plants because of the small space requirements, simplicity, reliability, low maintenance and quick starting characteristics.Fig. 1 shows the intercondenser and aftercondenser combined in a single shell. The intercondenser compartment is separated from the aftercondenser compartment by means of a common tubesheet. Special care is taken in the design and fabrication to prevent leakage between the intercondenser and aftercondenser compartments.This design has two first stage and two second stage ejectors. The two first stages as well as the two second stages operate in parallel. The advantage of flexibility is apparent as 100 pct or 200 pct air handling capacities can be obtained, provided the condensers are properly designed.In operation, it is usually necessary to operate only the first and second stage; the others jets are held in reserve. Block or Isolation valves between the second stages and the intercondenser are necessary to prevent short circuiting of air and vapor from the aftercondenser to the intercondenser through the standby ejectors. Also a block or isolation valve is also necessary for the suction side of each jet.

 

Here the intercondenser and aftercondenser are built separately. Either design will provide the same performance. The difference lies in the purchase cost and installation requirements.