Emissions

What are Pipeline Emissions?

Emissions are the constant loss of product from within a pipe through and/or around a sealing element. Emissions are directly correlated to the sealability of a gasket or sealing product. It has been stated that “all gaskets leak”, but what is acceptable and unacceptable? Many companies are creating mandates to reduce GreenHouse Gas Emissions (GHG Emissions) to reduce the footprint for greenhouse gases and the EPA has strict standards when it comes to emissions for the oil and gas process. The creation of these requirements can now make a gasket that was once acceptable for emissions no longer acceptable.

Emissions today may not have been emissions in the past. As sensing technology has gotten better and the world has become more environmentally conscious, stricter and stricter requirements have been put in place. Chemicals that are injurious to the environment are often labelled as VOCs and HAPs.

"Volatile organic compounds (VOC) means any compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, and ammonium carbonate, which participates in atmospheric photochemical reactions. Source EPA.

HAPS are Hazardous Air Pollutants, also known as toxic air pollutants or air toxics, are those pollutants that are known or suspected to cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse environmental effects. EPA is working with state, local, and tribal governments to reduce air emissions of 187 toxic air pollutants to the environment.

Methods for Measuring Emissions

Air Emission Measurement Center - The EPA hub for stationary source air emissions test methods and procedures.

Monitoring emissions under EPA's market-based (e.g., cap and trade) programs, more here.

Also, click here to learn more about vehicle and fuel emissions testing.

How are GHG (Greenhouse Gas) Emissions Measured?

There are many methods such as FID, FTIR, NDIR, airplane LIDAR, optical gas imaging, Aerostat Aloft Platforms, Radial Plume Mapping and Eddy Covariance Methods.

For more information we recommend viewing the EPA official website.

Greenhouse Gas Emissions by Country 2017

In a global effort to become less reliant on fossil fuels and more reliant on clean energy, hydrogen is and has been used as an alternative fuel source.  Hydrogen is the smallest known molecule, so sealing it is crucial especially since it has low ignition energy requirements and has high combustive energy properties.  Tight emission control of this element can be achieved through the use of non-permeable gasketing solutions and proper installation practices.

Importance of Installing a Flange Isolation Kit (FIK) Correctly

Another cause of emissions or poor sealability can be poor installation. Over 80% of gasket failures are due to improper installation practices or improper equipment conditions.

Leakage Rates of Isolation Gaskets vs a Spiral Wound Gasket

Note: Testing Performed at ambient temperature/500psig He /5hrs / 7,500psi gasket stress VCS-ID™ was single design only

Another major improvement to emissions and sealing is to participate in GPT’s GFIT program, GPT Flange Isolation Training.  This program certifies participants in the proper alignment of flanges, the correct method of evaluating flange faces, tried and true torquing techniques, inspection procedures and provides “hands on” elements for both installation and isolation gasket testing.

Which Sections of Oil and Gas Processing are Under Requirements by the EPA to Adhere to Emissions Standards?

Have you ever installed an isolating kit in a pipeline, successfully tested for electrical isolation, but later failed isolation following a hydrotest?

An Accurate Isolation, World Pipeline Magazine, Tim Hurley.

What part does load play with emissions and sealabilty?

 Proper compression of the gasket is extremely important, but can be usurped by poor flange conditions or installation practices. We recommend using an installation procedure like this and making sure that flanges are aligned.

Is there training that can be taking to improve sealability for our products?

There are two training programs that GPT offers. One is the GFIT (GPT Flange Installation Training) program and the other is a Level I, II and III training program that teaches more about product selection, design and use.

Are there pitfalls that I can avoid regarding emissions and sealability?

The common issue that we see is the use of homogeneous GRE products in gaseous applications and then concern when they initiate some type of leak detection. It is quite common for these types of products to permeate (especially under higher pressure), so for gaseous applications, we recommend the use of a PTFE ID sealed isolation product.

Can liquid permeate through my GRE gaskets?

Surprisingly, the answer is yes. With high pressure and time, the media can permeate through the GRE. Another reason we recommend a PTFE ID seal to prevent any media contact with the GRE.

Gasket Load on Insulation Gaskets

Gasket load can be as complex as emission monitoring. Gaskets typically have a psi (pounds per square inch) or a kPa (1 kPa is approximately the pressure exerted by a 10-g mass resting on a 1-cm2 area. 101.3 kPa = 1 atm.) minimum requirement and a maximum allowable limit (note the maximum can change if the gasket is subjected to exposure in a liquid). Let’s say a gasket has a minimum gasket load (or stress) of 3,000 psi or 20,684 kPa and a maximum gasket load (or stress) of 15,000 psi or 103,421 kPa. This means the gasket will start to effect an acceptable seal at the minimum stress and can begin to break down at the maximum stress.

A “good” load on this gasket might be around 10,000psi or 68,948 kPa. This allows for some bolt stress relaxation and gasket relaxation to occur before leakage or gasket failure. Now how does one achieve the proper gasket stress? The answer is in torquing the bolts to the proper level to achieve the required gasket stress. This is where it can begin to get “complex”. The proper gasket stress will depend on many variables (reused nuts/bolts, rusty nuts/bolts, calibrated torque wrench, aligned flanges, proper flange face RMS (root mean square) finish (should be concentric or spiral grooves), type of lubricant used (if any), type and number of washers used (should be two washers).

Even the orientation of the nuts can be a factor (printed side of the nut should face away from the washers). There are other factors that should be taken into account, but these are the primary factors. Much has been written on this subject and a good book to read is John Bickford’s book on “Gaskets and Gaskets Joints.'