PA AND SA FANS IN INDUSTRIAL PLANTS AND THEIR APPLICATIONS
                     PA AND SA FANS IN INDUSTRIAL PLANTS 
AND THEIR APPLICATIONS
Neel Rao
Writes on Reitzindia massive industrial fan and 
Primary air fans and secondary air fans from Reitz India
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There are various kinds of fans used in industries that enhance the capability of 
other industrial operations. They play crucial roles in processes like combustion, 
ventilation, and material handling. Two of these most significant fan types are 
primary air (PA) fans and secondary air(SA) fans. Here we understand what they are, 
how they work and explore their applications in various industrial settings in detail:
The Primary Air Fans are used during the initial stages of the combustion process. 
They supply primary air to mix the fuel and initiate the desired combustion reaction 
in an efficient manner. While the Secondary Air Fans are utilized at the secondary 
stages of the combustion process once the fuel is in the ignition. They supply 
additional air for the entire burning of the fuel. Both PA and SA fans have different 
applications based on several parameters, for example, airflow pattern, purpose of 
use, etc. Let’s have a look.
Purpose:
The PA fans help ensure adequate quantity of primary air is supplied for controlled 
and efficient combustion. They assist in initiating and supporting the main 
combustion process. On the other hand, SA fans supply secondary air or additional 
oxygen needed to complete the combustion, reduce emissions, and improve 
combustion efficiency.
Airflow:
In terms of airflow pattern, PA fans supply air in a pressurized but controlled way by 
adhering to the requisite air-to-fuel ratio in the combustion chamber. SA fans also 
provide air to the combustion chamber but with less pressure.\
Usage of PA fans in Industries:
Cement Production:
PA fans assist in delivering primary air to the cement kiln, aiding the combustion of 
fuel and contributing to the process of clinker formation.
Industrial Boilers:
PA fans supply the necessary primary air for combustion in boiler systems employed 
in several industries. This helps in maintaining temperature levels and efficiently 
producing energy.
Power Plants:
PA fans supply primary air for the combustion of coal in the boiler. They ensure fuel 
and air are properly mixed thereby optimizing combustion efficiency.
Waste Incineration Units:
To achieve complete and efficient burning of waste materials, PA fans supply 
necessary primary air to incinerators.
Metal and Steel Industries:
PA fans ensure proper combustion of fuels assisting in smelting and melting 
operations of metal by providing primary air to furnaces.
Usage of SA fans in Industries:
 Afterburning Chambers:
SA fans find applications in waste incineration plants where they supply secondary 
air for afterburning. This helps in reducing pollution further and ensuring 
environmental compliance.
Melting Furnaces:
In glass manufacturing melting furnaces, SA fans are utilised to provide secondary 
air to assist in the combustion of fuel and the melting of raw materials.
Chemical Processing:
SA fans ensure complete and controlled reactions in chemical processing plants by 
providing secondary air required for combustion or oxidation reactions.
Combustion in Boilers:
SA fans supply secondary air to the combustion process in the boilers ensuring a 
thorough mixture of fuel and air. They promote the full combustion of fuel and cut 
down emissions.
Steel Processing:
In certain high-temperature processes, SA fans provide additional air to support 
combustion, contributing to temperature control and material processing.
Cement Clinkers:
SA fans aid in cooling clinker in the cement production process. They provide 
secondary air to cool the hot clinker before it is churned into cement.
Biomass Plants:
SA fans supply additional air assisting in the combustion of biomass materials for 
energy production.
Air Pollution Control:
SA fans are utilised to provide secondary air for chemical reactions and reduce 
emissions in systems like selective catalytic reduction units or for flue gas 
desulfurisation.
Conclusion:
The bottom line is that understanding the distinct applications of PA and SA fans in 
industrial processes is vital for optimising the efficiency of combustion, controlling 
temperatures, and meeting environmental regulations. With proper design, 
operation, and maintenance, these fans enhance the overall efficiency and reliability 
of industrial plant operations.
About REITZINDIA
Reitz India has set a benchmark to deliver high quality fans for heavy duty industries 
which can work at precise operating conditions like high temperatures and 
pressures. Reitz offer idealistic Centrifugal Fan and Centrifugal blower design that 
can be used in all large scale process industries like cement, iron & steel, power 
plants, fertilizers/ chemicals and more.
Thank you for spending your precious time in reading this article!