Pressure Drop in Compressed Air System: Causes & How To Minimize It
It requires a significant amount of energy for an air compressor or air blower system to produce and provide compressed air from atmospheric air to pressurized conditions for getting work done at point of use.
Amidst all the things that occur in a compressed air system, having a pressure drop is common.
In this blog, we will explain the meaning of pressure drop, why pressure drop matters, its causes, and how to minimize pressure discharge using air blowers.
What Is A Pressure Drop?
Pressure drop is when there is a reduction in air pressure within an air compressor system. The pressure drop can happen anywhere between the compressor discharge and the actual point of consumption.
The pressure drop varies on the type of industry and application of air compressors. However, a general rule of thumb says that an ideal discharge pressure shouldn’t exceed 10 percent.
Why Pressure Drop Matters?
Higher pressure drop leads to poor system performance. An increase in pressure drop puts more strain on the equipment, which leads to more energy consumption to maintain the desired flow rate and higher electricity bills.
It is commonly known that for every extra 1 bar generated in pressure, we consume almost 7% more of the shaft power. Imagine how much this would cost you more on an average industrial-size air compressor.
Let us explain this using an example as well for better clarification.
Consider you are operating an air compressor unit of 160 kW at extra 1 bar pressure than what the application would require. This will cost more than 11.2 kW to pay for 1 bar extra generated, which is eventually expanded (wasted) using a pressure regulator in the process by the end to match lower application pressure.
In Dubai, industrial power costs 0.45 AED/kWh. According to our hypothetical scenario, this would mean 5.04 AED/Hr (11.2 x 0.45 = 5.04 AED/Hr). So, if you run your air compressor all day, all year long, it would cost you an additional whopping 44,000 AED, which is a lot!
And what if you own and operate multiple compressors? This figure will increase further, and that’s not even the last thing you want.
Suppose your facility requires multiple compressors with high flow rates to carry out heavy-duty applications such as pneumatic material conveying.
In that case, you should consider dedicated low-pressure compressor systems or air blowers as they will function efficiently with better overall reliability and without unnecessarily hiking energy consumption and, therefore, electricity bills. Also benefiting with lesser maintenance intervals.
What Causes Pressure Drop?
Several reasons can cause pressure drop. Any obstruction, deliberate or conventional, can cause resistance to the airflow, resulting in pressure loss
It can be because of the commonly used in-efficient practice of using a medium-pressure compressor that generates 7-8 bars for low pressure applications such as pneumatic conveying that requires 2-3 bars.
Businesses often use the traditional medium pressure compressors and bring its pressure down to 2-3 bars to carry out low pressure applications. This results in not just unnecessary power consumption and maintenance, but high costs as well which the facilities wouldn’t need otherwise.
Another reason which causes pressure drop is the air quality within an air compressor system. Contaminants such as water vapor, oil and other fumes affect the air quality and create resistance to airflow, resulting in pressure drop.
Read on to find out how each contaminant adversely affects the air quality and causes a pressure drop.
Water Vapor – water introduced at the compressor discharge can cause damage to internal parts and components. Always measure and monitor vapor content using pressure dew point temperature to avoid this.
Oil – Excess oil can clog the piping systems and lead to overheating.
Other Fumes – Gases and fumes in the air possess corrosive compounds that can disturb the process flow within an air compressor system and even affect the final output at the point of consumption.
How To Minimize Pressure Drops?
As mentioned above, pressure drop on a medium pressure line can be acceptable within range of 0.1 -0.5 bar depending on your installation and process. However, something’s wrong with your air compressor system and potential room for improvement if the pressure drop exceeds this level.
To optimize for your low pressure application such as pneumatic conveying, selecting the right type of equipment is the first and a significant step to take.
Choose from dedicated Low Pressure technologies available best designed to suit your demand profile, allowing you to have minimum pressure drops.
If you have a variable or fluctuating air demand, going for an oil-free rotary screw blower with a VSD would be a wise choice to make. For constant base low demands (larger air flows), a centrifugal blower would be a good fit. To optimum operations, you can even go for a hybrid solution where a combination of technologies can be done with a master controller Optimizer 4.0 for an efficient mix.
Other than using air blowers to control pressure drops, there are uncountable ways to fix an excessive pressure drop or loss. We have gathered the best possible solutions and divided them into short-term, medium-term and long-term.
- Short Term: It is possible that one of the seals or connectors is opened, which may be causing leakage, and, therefore, excessive pressure drop. So, make sure to check them. Also, make sure all the filters are clean and dirt-free.
- Medium Term: Install pressure monitors at different places within your air compressor system to identify overlooked gaps and leakages. Try to determine the exact spots which are causing unusual pressure drops. Run regular maintenance checks.
- Long Term: Create a comprehensive plan of your air compressor system with all the components and pipelines. Consider revising the pipeline network or replacing pipes creating unwanted pressure drops.
Additional ways to minimize pressure drop within your air compressor system include:
- Well-designed piping distribution network
- Air dryers to installation and moisture traps to avoid pipe corrosion
- Minimize air traveling distance within the network with the least possible bends and prefer closed-loop network
- AVOID using pressure regulators on medium-pressure lines for low-pressure applications
Identifying excessive pressure drop and minimizing it is imperative to avoid significant and unnecessary energy consumption and electricity bills.
Installing an efficient air blower from a reliable brand like Atlas Copco is the best way to control unwanted high-pressure discharge, produce cost efficient output and stay ahead of competitors.
Minimize Pressure Drops With Atlas Copco
For your convenience, we have summarized the best air compressor systems according to your pressure needs.
We are leading manufacturers and suppliers of compressed air systems in UAE. For low-pressure needs, Atlas Copco’s VSD air compressor systems are ideal, designed and developed in-house using the latest technology. Generally, for all low-pressure applications like material conveying, fermentation, or water treatment, Oil-free Class 0 air quality air is critical. Our VSD-powered air compressor systems guarantee your users a 100% uncompromised final product.
For more tips on how to keep your pressure discharge as low as possible, contact our low-pressure specialists today at Atlas Copco.