PA (Primary Air) and SA (Secondary Air) fans are commonly seen in industrial spheres facilitating regular functions they can manage. The main areas where these fans are installed include the combustion systems in industrial furnaces, boilers, and incinerators. The Primary Air and the Secondary Air fans are considered essential for industrial boilers as they can help manage the combustion process.

1. PA AND SA FANS USAGE IN INDUSTRIAL
PROCESSES
Neel Rao
Writes on Reitz India's PA fans and SA fans and Primary
air fans and secondary air fans from Reitz India.

2. PA (Primary Air) and SA (Secondary Air) fans are commonly seen in industrial spheres
facilitating regular functions they can manage. The main areas where these fans are
installed include the combustion systems in industrial furnaces, boilers, and
incinerators. The Primary Air and the Secondary Air fans are considered essential for
industrial boilers as they can help manage the combustion process.
The PA fans supply primary air to a boiler’s combustion chamber. The primary air can
be defined as the initial or first air stream that mixes and combines with the fuel to
help with the combustion process. The PA fans help ensure that sufficient quality of
primary air is provided to facilitate properly controlled combustion.

3. The SA or Secondary Air fans provide secondary air for the combustion chamber. The
secondary air gets introduced into the combustion process once the fuel has been
ignited. These fans help ensure complete combustion is carried out by presenting
additional oxygen for the burning fuel, thus enhancing the overall combustion
efficiency and reducing emissions.
Along with the above-mentioned usages, the PA and SA Fans are used in different
high-end industrial furnaces, like those used for steel-making, heat treatment, and
glass manufacturing processes. One of the main benefits of using PA fans is that they
help provide necessary air so that the fuel can burn efficiently and give rise to the
desired heat levels. The SA fans help the furnaces achieve complete combustion
through the process of supplying an additional amount of oxygen to the furnace’s
combustion chamber. These fans help ensure the fuel burns thoroughly and
contribute to maintaining the requisite furnace temperature.

4. The PA (Primary Air) and SA (Secondary Air) fans are used with the waste
incineration systems that help dispose of solid waste materials. When used in
incinerators, the PA fans can offer primary air for supporting the combustion of
waste materials. These fans can help maintain the desired temperature for proper
waste incineration. The SA Fans used in the incinerators provide the secondary air
that helps complete the combustion process. When the additional oxygen gets
supplied by the SA fans, it helps to ensure that all unburned and partially burned
traces of waste materials get completely combusted, thus minimizing emissions.
Differences between the PA and the SA fans
The differences between the PA (Primary Air) and the SA (Secondary Air) fans have
to do with their essential functions and the stage of the burning or combustion
process for which they are used. Here is a look at the main distinctions between the
two.

5. Based on purpose – Differences between the PA and the SA fans
Primary Air Fans
The essential purpose of the Primary Air is to provide the primary air needed to
manage the combustion process. The primary air functions, as the initial air stream
that thoroughly mixes with the combustion chamber fuel. The PA fans can help to
ensure that a sufficient quantity of primary air is supplied to achieve a controlled
and efficient combustion. Using the primary air assists in initiating and supporting
the main combustion process.
Secondary Air Fans
The Secondary Air fans supply the secondary air needed to help with the
combustion process. The secondary air is applied into the combustion chamber once
the fuel has been ignited. The SA fans can provide additional oxygen for the burning
fuel, thus helping with complete combustion, reducing emissions, and improving
combustion efficiency.

6. Based on the combustion stage – differences between the PA and the SA fans
Primary Air Fans
The Primary Air Fans are used at the initial stages of the combustion process. These
fans supply primary air to the combustion process for mixing the fuel and initiating
the desired combustion reaction. The PA fans can ensure a proper air-to-fuel ratio to
deliver controlled and efficient combustion.
Secondary Air Fans
The Secondary Air Fans are used at the secondary stages of the combustion process.
The SA fans can provide secondary air to the combustion chamber once the fuel has
been ignited and the combustion is initiated effectively. The main goal of using
secondary air is to provide additional oxygen for supporting complete combustion. It
helps to burn all traces of unburned and partially burned fuel elements and
particles.

7. Based on airflow pattern – differences between the PA and the SA fans
Primary Air Fans
The Primary Air Fans can supply the air in a pressurized and controlled way inside
the combustion chamber. In this way, they can support the combustion process and
adhere to the requisite air-to-fuel ratio.
Secondary Air Fans
The Secondary Air Fans also provide air to the combustion chamber in a less
pressurized manner when compared to the PA fans. The primary function of the
Secondary Air Fans is to offer additional oxygen to support complete combustion
instead of controlling the air-to-fuel ratio.

8. Therefore, it can be said that the Primary Air Fans are responsible for supplying the
primary air needed to handle the initial stages of combustion. They can help to
maintain the proper air-to-fuel ratio. On the other hand, the role of the Secondary
Air Fans is to support the appropriate combustion of the materials during the
secondary stages so that there is additional oxygen for burning any remaining traces
of fuel particles. The Primary and the Secondary Air fans work together to ensure
efficient combustion, enhancing combustion efficiency and reducing the emissions
produced in the combustion processes.

9. 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!