Effect of High Altitude on Steam Boilers

A high-altitude steam boiler is a type of Industrial steam boiler that is designed to operate at higher altitudes than a standard boiler. Boilers are designed to operate at a specific altitude and atmospheric pressure. When a boiler is operated at a higher altitude, the atmospheric pressure is lower, which can affect the boiler’s performance.

Here are some of the effects of high altitude on steam boilers:

• Reduced combustion efficiency: The lower atmospheric pressure at high altitudes means that there is less oxygen available for combustion. This can lead to reduced combustion efficiency, which can result in lower steam output and increased fuel consumption.
• Reduced heat transfer: The lower atmospheric pressure at high altitudes also means that there is less air available to carry heat away from the boiler tubes. This can lead to reduced heat transfer, which can also result in lower steam output and increased fuel consumption.
• Increased water carryover: The lower atmospheric pressure at high altitudes can also lead to increased water carryover. This is when water droplets are carried over with the steam, which can damage downstream equipment.

To address these challenges, high-altitude steam boilers are typically designed with features that improve combustion efficiency, heat transfer, and water carryover control. These features may include:

• Oxygen enrichment: Oxygen can be added to the combustion air to improve combustion efficiency.
• Superheaters: Superheaters are used to heat the steam to a higher temperature, which can improve heat transfer and reduce water carryover.
• Evaporator economizers: Evaporator economizers are used to preheat the feed water before it enters the boiler, which can improve combustion efficiency and reduce fuel consumption.

• Boilers designed to generate 5000 kg/hr steam for & at,100-degree Celsius at mean sea level will not give the same quantity of steam if shifted to an elevated place. It will generate less steam.
• Due to decreased air density at higher altitude, it will consume the same volume of air but will not consume the same mass of air.
• This results in less fuel consumption & less steam generation rate.
• Due to the reduction of mass flow of gases through tubes of a boiler, convective heat transfer also decreases which further results in reduced evaporation rates.

Combustion is a process which needs the constant air supply for its survival, but as we move up the earth i.e. at higher altitudes, things aren’t the same as they used to be at sea level. The oxygen content in the air reduces exponentially.

Also Check : Steam Boiler Calculator 

Unlike human body, a Steam Boilers doesn’t acclimatize itself to this shortage.

Though the Blower provides the same volume of air the reduced density of air (oxygen to be specific) leads to reduced combustion, lesser fuel consumption hence reduced steam generation.

So, it can be concluded that a Steam Boiler at its rated capacity, won’t keep up the promise of desired output at elevated levels. So, one should focus on the mass flow rate of air supplied for combustion instead of volumetric flow.

Knowledge of De-rating factor can help in quantifying the reduced output of the Boilers. A Proper volumetric flow of the Blower should be selected as per the conditions.

At higher altitudes, atmospheric temperature decreases, so to increase the Boiler Efficiency one must focus on increasing the temperature of feed water and air.

Also, the proper insulation of all the equipment must be ensured in order to prevent the heat losses due to convection and radiation.

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High Altitude on Steam Boiler FAQ