Your Personal Assistant – The Blower Sizing Tool

Blowers consume around 60% of the total energy used in the wastewater treatment plants, therefore they have a significant impact on the operational expenses. The efficient blower sizing is a key element even in the preliminary design stage.

Blowers are widely used in multiple positions in the wastewater treatment process, such as for grit removal, biological reactors, membranes (in case of MBR) or sludge storage tanks.

There are 5 blower types used in the industry:

  • Positive displacement /Rotary lobe
  • Dry screw
  • Multistage centrifugal
  • Single stage integrally geared centrifugal
  • High speed turbo gearless

Each of these has its own advantages and disadvantages and the blower selection process includes proper evaluation of these factors. The type of the blower determines electricity consumption, maintenance estimation, investment, and replacement cost. But the electricity consumption is just part of the evaluation. Outlet air temperature, noise, footprint, or weight can also be important depending on the project’s characteristics.

We developed a free tool for wastewater engineers to be able to do quick calculations on blower sizing. Let’s see a real-life example of how to use the tool.

Select best blower type for biological reactor

If the engineering team created the Process Scheme for the wastewater treatment plant, the air requirement for the biological reactors should be also calculated. If you created the design with Transcend Design Generator, the air requirement value can be found on the right side of the Process Scheme as shown in the below picture.

You can take this value and insert it into the Blower Sizing tool. In this specific example, we will do the calculations for the max air requirement and inserted 8485 m3/d into the calculator and assumed 600 mbar differential pressure, based on the 5m depth of the reactor. ( 5m * 9.81 m/s * 1000 kg/m3 = 490.5mbar, and we consider 109.5mbar for pressure loss on the diffusers and on the pipe).

In Scenario 1, the efficiency was set to 50%, as a trial for Positive Displacement w/VFD blower type. The result is the following:

It’s important to note that the energy consumption is calculated based of adiabatic theory, while the temperature rise is calculated in both adiabatic and polytropic way, and the higher is selected to be on the safe side.

After creating 4 scenarios, we can create the below summary table:

Scenario 1Scenario 2Scenario 3Scenario 4
Efficiency50%65%75%80%
Avg Consumed Power9.9 kW7.6 kW6.6 kW6.2 kW
Installed Power11 kW11 kW7.5 kW7.5 kW
Outlet Temperature103.3 C84.1 C75.5 C72.1 C
Blower typePD w/VFDMulti-Stage CentrifugalHigh Speed Turbo Gearless CentrifugalSingle Stage Integrally Geared Centrifugal

We can use this comparison table to support our blower type selection process. Average consumed power provided by the Blower Sizing Tool is a suitable estimation in the preliminary phase’s opex calculation, as both processes and mechanical requirements are built into the calculation. Exact consumption data will be provided by the manufacturer upon selection.

The other outcome of the tool is the outlet temperature. According to the laws of thermodynamics, we can take the assumption that the higher temperature requires more durable instrumentation or piping elements, which can also imply additional cost. The outlet air temperature can also have other effects on the design, for example, reactor depth or pipe length. In our next use case, we will be presenting how the blower sizing tool can help to find the optimal reactor depth and energy consumption of the blowers. In the meantime, feel free to share your thoughts on how you utilize the Blower Sizing tool.

Clients

Technology Providers & OEMs Technology Providers & OEMs

TDG rapidly generates accurate budgetary proposals to help suppliers bid more, win more, and sell more.

Asset Owners and Utilities Asset Owners and Utilities

TDG streamlines the capital planning and conceptual design processes to accelerate project timelines and deliver better outcomes.

EPCs, AECs, and Consultants EPCs, AECs, and Consultants

TDG enables engineering firms to deliver more value to their clients & increase competitiveness.

Individuals Individuals

TDG works for individual engineers who want to grow their business and reduce their non-billable time.

Academic Academic

Transcend supports students and professors around the world to incorporate TDG into their curriculum.

Resources

Articles Articles

Read posts written by Transcend team members sharing their points of view on the company mission, vision, and products.

Webinars Webinars

Watch on-demand webinars like Transcend’s popular ‘How To’ series.

Case studies Case studies

Understand how Transcend’s customers are utilizing TDG to bring more value to their customers and grow their businesses.

FAQ FAQ

View a list of the questions we are most frequently asked about our company and our software

Transcend tools Transcend tools

Access a number of tools Transcend has developed to help engineers and industry professionals take back their time.

Security Security

Learn more about Transcend’s security practices

Industries

Water and Wastewater Water and Wastewater

TDG creates unique, optimized designs of water & wastewater treatment facilities by automatically combining decisions and calculations from each engineering field.

Power Power

TDG creates unique, optimized designs of T&D assets by automatically combining decisions and calculations from each engineering discipline.