Surge Tank Function Full Video | Blast Furnace | Operation | Tech It Eze

Hi Friends
Today we will discuss about Surge tank Functions and its Operation.
SURGE TANK FUNCTIONS
The expansion tank in a blast furnace closed-loop water system serves several critical functions:
 Temperature compensation: Allows for thermal expansion and contraction of the water volume as it heats up and cools down, maintaining a stable system pressure.
 Pressure regulation: Helps regulate system pressure by providing a buffer against sudden changes in pressure, preventing damage to pipes and equipment.
 Air removal: Enables the removal of air pockets and dissolved gases from the system, ensuring efficient heat transfer and reducing corrosion risks.
 Water level control: Maintains a consistent water level in the system, ensuring adequate cooling and heat transfer.
 System protection: Protects the system from over-pressurization, which can lead to equipment damage or failure.
 Water quality management: Helps maintain water quality by allowing for the removal of contaminants and sediment that may accumulate in the system.
The expansion tank is typically designed to accommodate the maximum expected volume expansion of the water in the system, ensuring safe and reliable operation of the blast furnace cooling system.

 Surge tank have following components. We will discuss one by one.
 TUYERE or STAVES COOLING PUMP – it Supply primary or soft water at design flow & pressure.
 TUYERE or STAVES – Tuyere Cooling required for protecting Tuyere from burning and water ingress into the furnace.
o Staves Cooling required for safe guard furnace refractory

 Heat Exchanger – Heat taken out from Tuyere or Stave return water or (primary Circuit) and given off into Secondary Circuit through Heat Exchanger without mixing primary & Secondary water.
 Expansion or Surge Tank – A Closed tank, Volume of tank depends upon expansion capacity of recirculation water. Tank normally occupy 60 ~ 90% soft water and rest part pressurized Nitrogen.
 Secondary Pump – Supply industrial water at designed flow & pressure.
 After Heat Exchanger, Secondary water gains heat which, in cooling tower it gives off heat & again it recirculate.
 Cooling Tower – Receives water from heat exchanger at higher temperature, cools down it & supply water at lower temperature.
o Note: Detail function & working of cooling tower will be discussed in a separate video.
 Slow Filling – In case of Expansion tank low level reached, Slow filling pump starts & make up done at a lower flow rate.
o Fast Filling - In case of Expansion tank low low level reached, fast filling pump starts & make up done at a higher flow rate.
 Nitrogen – Required to maintain water level stability inside the surge tank & pump suction pressure.
 Level transmitter & Level Sensor – Continue shows the level in expansion tank and as per plan start or stop make up water (filling). Suppose, at 60% - filling starts, at 90% - filling stop, at 40% - fast filling or alternate water source start, at 20% Surge tank Isolate.
 Surge tank isolation: In case of very very low level in expansion tank, Nitrogen gas may enter into circuit and affect on pump, that’s why, it is a safeguard to isolate the surge tank & don’t allow Nitrogen into water circuit.
 Make up SOV (Shut Off Valve) – It Opens during Expansion tank water filling (60% level) and Closes after reaching expansion tank water level (80 or 90%).
 Emergency or Alternate Make Up Source SOV – Used only in case of Emergency (water level goes below low low level due to heavy leakage in Circuit)
 Tank Pressure – A pressure transmitter and or a manual pressure gauge installed in upper part of the expansion tank, which shows tank pressure.
 Auto Vent Valve – If tank pressure is greater than set point, then vent valve opened automatically to maintain the tank pressure as per pre-defined set point.
 Auto PRV (Pressure Regulating Valve) – It maintains tank pressure as per set point. It Opens if tank pressure is less than set point and closes if tank pressure reached the set point.
 Inlet Nitrogen gas Pressure – A pressure transmitter and /or a manual pressure gauge installed in inlet nitrogen line of the expansion tank, which shows Nitrogen gas pressure.
Hope you understand
In case of any doubts please mention in comments.
Thank you for watching.
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