Bag Leak Detection Blog

Since the early 1990's, industrial facilities have become accustomed to being required to comply to specific reporting, record keeping, and other Maximum Achievable Control Technology (MACT) standards that were defined in their Title V Operating Permit for any "major source". The Clean Air Act defines a “major source” as a one that emits, or has the potential to emit, 10 tons per year of any hazardous air pollutant, or 25 tons per year or more of any combination of hazardous air pollutants (HAPs).  Sources with emissions below this threshold are classified as “area sources.” Different control standards apply to the source depending on whether or not it is classified as a “major source” or an “area source.”

Last week, the EPA issued a guidance memorandum withdrawing the “once in always in” policy for the classification of major sources of hazardous air pollutants under section 112 of the Clean Air Act.  This decision allows industrial facilities the opportunity to reduce HAPs emissions to below major source levels and no longer be required to comply with the major source MACT standards.

Any investment in new technology, maintenance process or a management system is usually evaluated by the likely return on investment. Triboelectric particulate monitoring systems are no different. Many facilities are required to use the technology for compliance. In others, however, investing in a triboelectric particulate monitor may be a business decision, the same as adding additional instruments and controls. The calculation of ROI can be more complex when considering detectors all the way down to the compartment and row level, and when investing in baghouse control systems.

This article explores the 4 main benefits of triboelectric monitoring of PM emissions and provides some tips on justifying the investment.

Directly Measure Particle Velocity

Just like in dilute phase conveying systems, dust collection systems require the bulk materials stay entrained in the air stream.  This is accomplished when the air speed in the systems remains at or above the minimum conveying velocity for the product. If it dips below the minimum conveying velocity (also called transport velocity) the dust particles will begin to settle out of the air stream. Dust collector systems are engineered for certain parameters based on things like fan size, duct configuration, and filter media.  Once in operation, it is more common that the engineered conditions do not always match the reality of the process conditions.Directly measuring the particle velocity inside the dust laden duct can provide operations the means to understand and even optimize the performance of their dust collector system.

Problems Caused By Low Air Velocity In Dust Collection Systems

Find and fix it fast!

One of the many benefits of triboelectric particulate monitors is the ability to detect leaking filter bags quickly. In fact, triboelectric systems for dust collectors are often (and rightly) referred to as “leak detection systems”, “bag leak detectors” or “broken bag detectors”. Interestingly, most dust collector OEMs recommend “dust collector leak testing” as part of their preventive maintenance schedules. This leads many to ask whether or not triboelectric leak detectors replace normal baghouse leak testing. Let’s consider this topic and see what role both play in maintaining your dust collection system. 

What is Baghouse Dye Leak Testing?

Maintaining peak collection efficiency in a fabric filter dust collector requires no individual filters leak at all. Even just one leaking filter among hundreds in larger systems can cause the system to exceed its maximum allowable emissions. For this reason, plant operators must keep a close watch on the filters in their systems and quickly identify and replace any damaged filters. But how do you find a small amount or even just one broken filter bag among dozens or even hundreds of filters in a dust collector? 

Do you monitor your dust collectors?

Baghouses and dust collectors have the reputation for being neglected or a source of constant maintenance problems. Some facilities have to monitor their dust collectors based on their local, state or federal reguations. Thrugh the years it has been common to simply monitor the differential pressure, or just visually inspect the outlet stacks. Triboelectric broken bag detectors and bag leak detection systems have been around for decades now. Let’s take a look at how a triboelectric dust collector monitoring system can bring benefits to your facility.

Many may feel that modifying or renewing an air permit can be a time consuming task, a new permit provides an opportunity to incorporate new monitoring technology that has other benefits. For instance, some may ask whether they should continue using opacity monitoring for their CAM requirements or if can they eliminate much of their manual monitoring by taking the opportunity to review their current practices.

First Emissions Monitoring Methods

Multiple Demanding & Dusty Applications

Cement plants rely heavily on dust collection systems for various processes in their plants. From capturing emissions from their boilers and kilns, to conveying systems used to move cement and other bulk materials around, to silo bin vents. What benefits can triboelectric technology from Auburn Systems provide in all of these areas within a cement facility?  

Here two areas where implementation can simplify compliance and improve operations.

Use Opacity Monitoring with Triboelectric Particulate Monitoring

What happens when the trackers aren't tracking?

Problems within pneumatic conveying systems can quickly cascade into large production issues for facilities. These can cause disruptions to batch products, overflows can create cross contamination between products or processes, and blockages can damage equipment or create safety hazards including combustible dust hazards. So it's understandable that fill level indicators are carefully monitored on bins or hoppers in manufacturing processes. 

However, what can be done if these indicators malfunction for some reason? Having a fail safe or backup monitoring source for these systems has proven a wise investment for many facilities. 

Using Triboelectric Flow Monitors As Backup Monitoring

Differential Pressure - Not necessarily the best parameter for dust collector/baghouse monitoring

DP is the king of dust collector monitoring metrics. However, some users have come to think that it is the ONLY metric to monitor on an industrial dust collector. This certainly is not the case…especially as the size and complexity of the system increases. Here are 4 important areas for which differential pressure cannot provide adequate insight.  

Total Emissions Levels

Let's Get Real About MACT

Ask any environmental compliance engineer what their biggest worry is and they will likely mention something involving MACT (maximum achievable control technology) standards. As MACT standards come to cover more and more industries, many facilities have found achieving compliance to be a significant challenge. Frequently they find that under investment in air pollution control over a number of years substantially complicates their compliance. Some have held out for political change that they assumed would lead to a revocation of these standards. Although the MACT program is firmly established by law and not subject to any executive directives or revision like some other standards, they've built programs of minimal compliance assuming that MACT would be reversed. It hasn't. It's exceedingly unlikely that it will. 

What Are MACT Standards?