ANS:B - entrainment separator

A steam ejector is a device used to remove gases or vapors from a system by creating a vacuum. It operates based on the principle of fluid dynamics known as the Venturi effect. Here's how it works:

1. Steam Inlet: High-pressure steam is introduced into the ejector through a nozzle.
2. Nozzle: The high-pressure steam enters the nozzle, where its velocity increases as it passes through a converging section. This increase in velocity is accompanied by a decrease in pressure, according to Bernoulli's principle.
3. Diffuser: After passing through the nozzle, the steam enters a diverging section called the diffuser. In the diffuser, the steam's velocity decreases while its pressure increases. This decrease in velocity and increase in pressure are due to the expansion of the steam as it moves into the wider section of the diffuser.
4. Suction Inlet: As the steam exits the diffuser, it creates a region of low pressure at the suction inlet of the ejector. This low pressure acts as a vacuum, drawing gases or vapors from the system into the ejector.
5. Mixing and Discharge: The gases or vapors from the system are entrained into the steam flow as it moves through the ejector. The high-speed steam entrains the gases or vapors and carries them along. Finally, the mixture of steam and entrained gases or vapors is discharged from the ejector.

Steam ejectors are commonly used in various industrial processes where the removal of gases or vapors is required, such as in vacuum distillation, vacuum drying, and vacuum evaporation systems. They are known for their simplicity, reliability, and ability to produce high vacuum levels.