Although air blowers are widely used in the chemical and petrochemical industries, mining, power generation and fluidization, their capacity is often limited.

There are several options for increasing the capacity of this type of equipment without necessarily replacing it:

• Modification(s) to the blower and/or drive machine.
• Cooling of intake air by water misting or cooling with refrigeration units.
• Oxygen injection at blower discharge.

This article focuses on machine modification.

Capacity limitation is often linked to the maximum speed of the blower and drive unit. This limitation is particularly noticeable during the summer months, when the blowers have to run at maximum speed to deliver the maximum mass flow required by the process.

A precise analysis of the blower’s performance is therefore required to identify the causes of the current limitation, and to determine the most suitable route for a capacity increase project.

Indeed, several factors can alter or limit the performance of the blower and drive machine assembly, depending on whether the blower is driven by a turbine or an electric motor :

• Modification of the installation at both the suction and discharge of the blower, resulting in increased pressure drops and, consequently, an increase in the required polytropic head.
• Fouling of the internals and/or suction filter.
• Alteration of blade roughness (in the case of an axial fan).
• Increased clearances in the sealing labyrinths.
• Loss of power to the drive machine, in the case of a steam turbine, through loss of enthalpy resulting from degraded steam conditions, either at the inlet or at the outlet.
• Degraded efficiency, maximum flow beyond the best efficiency point of the design.
• Mechanical limitation linked to maximum permissible stresses as a function of speed (blower or turbine).

We will start by establishing a health check of the machine to assess the current operating point and efficiency in relation to the original curves. This pre-study will be carried out on the basis of :

• Original manufacturer’s documents (data sheet and performance curves)
• Results of an on-site performance test
• Specifications for the future performance point (flow rate, discharge pressure, pressure, temperature and humidity at suction).

The conclusions of this pre-study will enable us to establish a precise diagnosis and select the best option for modifying the air blower and/or the drive machine. Several options may be considered:

• Renovation of the blower, if there is a significant loss of efficiency but the potential is confirmed.
• Minor modification of the existing rotor (new impellers and internal parts).
• Major modification of the internals (complete replacement of rotor and internals).
• Modification of the drive machine to increase either speed or power.

PRIMCO will then carry out the final study in collaboration with the Original Equipment Manufacturer or a third party, based on the conclusions of the pre-study and with the machine’s definition drawings and documents, or with a complete set of spare parts (rotor and internals).

Prefabrication of parts can be carried out without immobilizing the blower, final assembly being carried out during a unit shutdown.

To diagnose your air blower, please send us the following information: