A steam jet air ejector (SJAE) is a device that uses high-pressure steam to create vacuum by entraining gases or vapours from a system. It operates based on the Venturi principle, where high-velocity steam creates a low-pressure zone that draws in gases and discharges them at a higher pressure.
Functioning of steam jet ejector in power plants plays a very vital role, Ejectors are used to create vacuum in steam Turbines. Higher the vacuum in steam Turbine, higher will be the performance of Turbine. Ejector evacuates the non-condensable gases present in the steam.
What are the various troubleshooting associated with steam jet air ejectors (SJAEs)?
Common issues associated with steam jet air ejectors (SJAEs) are ;
- Low inlet steam pressure
- Low inlet steam temperature
- Vacuum fluctuation
- Safety valve leakage
- Air ingress from joints
- Nozzles worn out
- Noise and Vibration
- Poor condensation formation
- U loop/seal breaking
- Vacuums trap failure
- More steam consumption
Steam jet air ejector (SJAE) troubleshooting guide.
| Sl No. | Problem | Cause | Remedy |
| 1 | Low vacuum | Low steam pressure | Check and correct steam pressure |
| Low steam temperature | Check and correct steam temperature | ||
| Poor performance/damaged nozzles | Replace the damaged nozzles | ||
| Air ingress into the vacuum system | Check & arrest all air ingress points | ||
| High condensate temperature | Check the performance of condenser, clean if required | ||
| Lack of cooling water flow | Check and increase the cooling water Check recirculation valve operation | ||
| 2 | Fluctuating Vacuum | Fluctuating steam pressure | Check pressure control valve and set it properly |
| Air leakage entering the system | Check & arrest all air ingress points | ||
| Fluctuation in Turbine load | Maintain stable load on Turbine | ||
| Improper working of vacuum traps | Set the vacuum traps properly | ||
| Water droplets entering into the ejector along with the steam | Ensure correct temperature of steam | ||
| 3 | Excessive Steam Consumption | Worn Steam Nozzle | Inspect steam nozzle condition and replace if required |
| Improper Operating Pressure | Set design steam pressure and temperature | ||
| Incorrect Ejector Size | Verify and rectify the ejector size | ||
| Condenser Inefficiency | Review the condenser performance and other operating parameters | ||
| 4 | High Condenser Pressure | Inefficient Ejector Operation | Verify ejector operating parameters and identify the root cause |
| Cooling Water Temperature Rise | Check cooling water flow and temperature and set it properly | ||
| Fouled Condenser Tubes | Clean condenser tubes | ||
| Excess Air Ingress | Identify air leakage sources and arrest those | ||
| 5 | Poor Air Removal | Ejector Nozzle Blockage | Inspect nozzle and diffuser |
| Poor performance of condenser | Check inter-condenser performance | ||
| High Back Pressure | Monitor back pressure | ||
| Steam Quality Issues | Ensure dry steam supply | ||
| 6 | Ejector Noise or Vibration | Wet Steam | Ensure dry steam supply |
| Improper Steam Pressure | Set desired pressure and temperature | ||
| Mechanical Damage to the nozzles | Inspect nozzles regularly and replace damaged nozzles | ||
| Condensate accumulation in steam lines leads to water hammer | Ensure proper draining of steam before taking ejector into line. | ||
| 7 | High condensate temperature | Lack of cooling water | Check and increase Cooling water |
| Poor performance of condenser | Verify the ejector parameters | ||
| Not working of vacuum traps and U seal | Set the trap and U seal properly Fill the U seal with DM water before taking ejector into line |
What are the best operating practices for Steam Jet Air Ejectors?
- Maintain stable steam supply
- Ensure proper steam dryness
- Maintain adequate cooling water
- Regularly inspect vacuum pipelines
- Keep condenser tubes clean
- Maintain Proper Motive Steam Pressure
- Avoid operating ejectors at low steam pressure, as it reduces suction capacity.
- Monitor steam pressure at the ejector inlet regularly.
- Ensure Dry and Clean Steam Supply
- Prevent Air Leakage in the Vacuum System
- Inspect Ejector Nozzles Regularly
- Maintain Proper Steam Line Drainage
Why dry steam is important for SJAEs?
Wet steam or steam carrying condensate reduces the velocity of steam exiting the nozzle, which reduces vacuum generation.
Wet steam leads to following issues?
Wet steam leads toWater hammer, Reduced steam velocity and Internal equipment damage
What is the purpose of inter condenser in multi-stage ejector?
The inter condenser condenses the motive steam between stages of ejectors.
- Reduces load on the second stage ejector
- Improves vacuum efficiency
- Reduces steam consumption
