Cut Compressed Air GHG Emissions
EP Editorial Staff | December 1, 2022
This roadmap helps you cut air-system waste, implement monitoring systems, and improve overall performance.
By Ed Duda & Mike Kusch, Motion
Sustainability has become dominantly relevant in the industrial revolution and manufacturers are supporting the overall impact of environmental and social responsibility. Environmental, social, and governance (ESG) policies are sweeping through every organization because stakeholders require more than profitability. In today’s culture, creating a dynamic vision and embracing environmental and social impact on a daily basis are essential.
Compressed-air systems continue to be one of the highest industrial utility expenses, while being one of the most neglected, from a maintenance perspective. These systems provide significant opportunities to achieve gains in efficiency and ongoing sustainability. Identifying the waste and developing projects to decrease or eliminate it are crucial initial steps for GHG reduction. Once the waste has been addressed, the necessary next step is installing a monitoring system to ensure the demand is maintained moving forward.
Developing an ESG roadmap for compressed-air systems can be achieved in four steps:
Engage a qualified partner to support achieving ESG goals.
In the past twenty years, proper monitoring has been left out of compressed-air projects. Less than 5% of customers properly monitor their systems. Some even reach the point of mistreating them. Without the required real-time data for key operating variables, this leaves customers susceptible to many issues. Operating a compressed-air system without a comprehensive monitoring system is the equivalent of running your car without any modern advancements in GHG emissions, sensors, or gauges. Inevitably, the vehicle will operate inefficiently, run out of gas, overheat, or worse. Developing a relationship with a strong partner will help you identify where waste occurs in the system, how to overcome the waste, and how to monitor and maintain ESG commitments.
Understand where supply- and demand-side waste exists.
Compressed-air systems are divided by supply and demand. The supply consists of the equipment required to generate and treat the air, while the demand comprises various end users. According to a recent Department of Energy (DOE) survey, 10% of all electricity consumed by the average industrial facility is used to generate compressed air. The consumption rises to 30% for some facilities.
Supply-side inefficiencies can result from dated air-compression technology; mechanical performance oversizing; control gap; lack of sequencing, leading to multiple units running at partial capacity; and/or excessive pressure. An example of this was identified during a system analysis where a facility was experiencing mechanical issues with a 200-hp compressor that forced it to pull a linear 50% of its rated 166 kW. The unit was pulling 75.99 kW, or 570,837 kWh. By addressing the mechanical issue, 478,869 lb. of carbon were reduced while overall system efficiency increased. Additionally, for every 2 psi a compressor operates in excess, 1% of additional compressor power draw is required. Furthermore, components such as dryers can account for additional inefficiency based on their type, control, and size for the system’s demand. Automatic drains, pressure loss, and surge can also lead to supplementary areas for improvement.
The DOE also states that 20% to 30% of total compressor output can be attributed to demand inefficiencies, specifically leaks. Inefficiencies within the demand of the compressed-air system are the most common area for improvement, yielding a typical payback between three months and a year. The inefficiencies, or waste, are attributed to leaks, open-air blow, air motors, air vibrators that run without proper controls, and facility areas that remain pressurized when production is not operating.
For example, a food-and-beverage facility experienced a leak load of 1,293 ft3/min. Based on system variables, this was the equivalent of 249.24 kW, or 2,174,546 kWh. By addressing the leaks, a calculated reduction of their carbon footprint was 1,824,204 lb. of CO2 in year one. Additional system savings were realized by reducing demand, allowing the facility to operate with less equipment. The overall project resulted in 4,704,830 kWh, or 3,870,193 lb. of CO2 reduction.
Identify defects causing waste and remedy them.
A vital step to identifying waste is completing a compressed-air energy assessment. This provides insight into how a system operates in its current state and how a future state can improve efficiency. An assessment’s primary goal is to realize immediate savings and create a roadmap for sustained results. This is achieved by identifying a baseline for how the system is currently operating, the potential savings (bottom-line savings and carbon reduction), and recommendations to alleviate the burden on the facility.
The overarching responsibility is to maintain annual carbon-reduction initiatives. The survey should become a standard operating procedure that requires fewer resources each time it’s conducted. This will allow the facility to be proactive in the event of failure, or on a routine basis throughout the year.
Identify proactive methods to monitor and maintain ESG commitments.
Today, technology exists to continuously monitor compressed-air systems. Various sensors promote the totality of a system deployed within a facility. Overall system parameters are essential, such as amp draw, airflow, and pressure for each independent compressor system within a facility; power draw for each compressor; and dew point for each dryer within the system.
To help prevent catastrophic failure, a complete system will include vibration and temperature sensors on each compressor to safeguard production while allowing maintenance personnel adequate time to order parts or call for service. In addition, each unit should have an amp meter to monitor power draw and provide analytical data regarding compressor performance. Dryers should have a hygrometer to detect an increase in moisture carryover as performance erodes. Preventing bulk water carryover will protect the downstream equipment and decrease the potential for leaks.
Mainline flow and pressure analysis from each system within a facility will help identify when demand either spikes unexpectedly or increases gradually over time due to an increased leak load. This allows timely maintenance scheduling to address a known issue instead of blindly fixing leaks. The results can be tracked in real time and reported to management and the company stakeholders.
Assess. Monitor. Maintain.
Optimizing a compressed-air system and arming it with the necessary technology to enhance its performance and provide traceability to sustainability goals must become the standard. Bottom-line cost savings plus carbon reduction offer stakeholders value for years to come. Understanding the detriments and opportunities of a compressed-air system will lead to exceptional results. To properly assess monitoring and maintain the performance of a compressed-air system, take the following actions:
• Secure a baseline system analysis.
• Understand the areas of opportunity and take action to drive results.
• Install the necessary monitoring equipment to allow facility personnel a proactive and educated approach to maintaining the system.
With these important tools, a compressed-air system can become a shining example of optimization at the facility instead of the fourth utility that everyone neglects. EP
Ed Duda is Senior Manager of P²MRO at Motion, Birmingham, AL (motion.com). He has a multidisciplinary background in operations and maintenance excellence and extensive experience in operational and maintenance strategy execution, lubrication program development and deployment, and applying Industry 4.0 technologies within manufacturing facilities.
Mike Kusch is Energy Services Manager at Motion. He has performed and provided deliverables on hundreds of compressed-air energy surveys across North America in a wide span of industries for 10 years.
Learn more at Motion.com/efficientplant.