extraction separation cell

Digging in the dirt: Fugitive emissions vs dirty oil

Gobind Khiani - 30 June 2016

This is the second part of the series of articles on the topic of oil sands.

About the author

Mr Gobind Khiani
Gobind Khiani P.Eng. (AB, BC, SK) is a Valve World columnist and Lead Discipline Engineer at Fluor Corporation, Canada.
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Climate Change 101

What are GHGs? The earth’s temperature is maintained by the greenhouse effect. The increase of Green House Gases by deforestation and burning of fossil fuel causes changes in the Earth’s temperature and is known as the GHG effect. What causes climate change? Factors such as volcanic activity, Earth’s orbit, changes in energy from the sun and actions by mankind such as burning fossil fuel, deforestation and other man made emissions all contribute to climate change.

What is climate change?

Changes in the weather pattern caused by storms and factors influenced by mankind, known as global warming which influences climate change. Oil production brings emissions: the mining of thick deposits of oil in oil sands, the source of emission from mining operations, results from the energy used to move earth, breaking it into smaller pieces and the heating of water during the extraction process. The source of emissions from in-situ (SAGD,CSS) operations is the burning of natural gas to generate steam. Greenhouse gas emissions also result from various processes used in upgrading bitumen into synthetic crude oil.

Climate change: facts

Firstly, climate change is real. Our planet is warming and it’s doing so at a faster pace than at any other time in our history(monitored or recorded). Secondly it’s very likely that GHG emissions caused by human activities such as fossil fuel burning and cutting forests are to blame for most of the warming in the past 250 years, thus confirming the broad acceptance by science of the link between GHG and climate change. Regulation – Codes i.e. AER, CSA, API,ISO, NACE, EPA and valve industry contribution in improvement towards low emission valves. A Journey to fact finding on Emissions by Gobind Khiani, P.Eng., on Valves states: Minimizing the potential for leaks via equipments (such as Valves) by applying proper design and material-selection standards is the first step in emission prevention.

Valve Emissions and management 101

Fugitive emissions are any chemical in a physical form that can leak, unexpectedly, within an installation. Valves account for more than 60% of fugitive emissions, and GHGs are part of this. Leak screening should be completed on accessible components using a portable organic vapor analyzer in accordance with U.S.EPA Method 21, or using alternate methods that provide an equivalent result. Operators in refineries or chemical/petrochemical plants must keep greenhouse gases (GHG) and environmental regulations for fugitive emissions in mind. One area in which this is extremely important is the processing of oil and gas. A few laboratories in North America, Europe and Asia are qualified and have developed a simple test procedure that can be adjusted to accommodate any off-the-shelf valve and provide the fugitive emissions in ppm, which is needed to understand how a valve will perform once it is in service.

the percentage of valves

Why fugitive emissions of valves?

The industry statistics indicate the importance of discussing the fugitive emissions of valves specifically. Valves account for more than 60% of fugitive emissions, and GHGs are part of this (see Figure 1).Compliance standards should be created by valve manufacturers that minimally include the following:

  • Design of sealing components
  • Selection of materials
  • Prototype qualification of valves
  • Production test of valves
  • Fugitive emission compliance onsite

To maintain consistency, each standard should be quality checked. If any anomalies occur, the whole test cycle must be repeated. The steps to eliminate or limit valve fugitive emissions that can lead to global warming include leak detection and repair and basic control and monitoring strategies.

Fugitive Emissions Leak Detection and Repair (LDAR)

true costs of fugitive emissions
The true costs of fugitive emissions.

The U.S. Environmental Protection Agency (EPA) aggressively pursues fugitive emission violations. It requires Method 21 Department of Energy (DOE) monitoring of valves, and it mandates the repair of leaks. To minimize hazardous or toxic air pollutants emissions, the EPA also mandates the use of low emission (Low-E) valves or Low-E packing. Valves and packing are considered Low-E if they have the following characteristics:

  1. They are type tested (by the valve/packing manufacturer) and have a written warranty not to leak above 100ppm. The manufacturer will replace thevalve if it emits above this limit at anytime during the first five years
  2. They are type tested and did not leak more than 500 ppm and, on average, leaked less than 100 ppm
  3. Valves that are extensions of the qualified types above, provided temperature, pressure and all major characteristics affecting the valve sealing performance are the same, are also considered Low-E.
sources of fugitive emissions
Figure 1: Sources of fugitive emissions.

Control Strategies

The key elements for effective, long-term control of fugitive emissions are:

  • The application of the best available technology and standards, including the development of monitoring programs, operating procedures and performance objectives for controlling fugitive emissions
  • Implementation of management systems
  • Corporate commitment to the implementation and maintenance of a directed inspection & maintenance (DI&M) program to detect and prevent leaks.

Several emerging technologies have the potential to improve the efficiency and effectiveness of leak detection programs and replace U.S. EPA Method 21. These technologies include:

  • Differential lasers to measure atmospheric concentrations of component gases
  • Computer analysis of ambient air sample trends to estimate leak source location and volumes
  • Infrared optical technology to visually inspect the components.

International standards and user test methods
Table 1 above shows International standards and user test methods. Valve emissions have been reduced in North America and Europe. However, they have increased or have been minimally changed in the rest of the world.

Current EPA guidelines have driven reduction in valve emissions by handling issues such as:

  • Leaks greater than 10,000 parts per million (ppm) are being eliminated.
  • Leakage to 500 ppm maximum is being limited.
  • New API 624 is moving toward allowable leakages of 100 ppm or lower.
  • Awareness of environmental initiatives in North America has grown tremendously and such initiatives have given visibility to projects such as the Keystone XL Pipeline.
  • Hydraulic fracturing is being examined more closely and codes and regulations in this space have been updated.
  • Policy makers are becoming strict and inspectors are imposing fines when necessary.

End users are working closely with the standards organizations to develop mandatory requirements on API 622 and API 624 such as maximum stem to seal tolerance allowance (finishing), Criteria on leakage rate/s, maximum temperatures, minimum temperatures, leakage class, cycles etc. In fugitive emission testing, the braided packing has been successful, which is cost effective for retro fitting existing and stock valves. Braided packing can be installed during shutdown or replaced during a valve refurbishment program.

The Future

The debate continues about the development of fugitive emissions regulations from the EPA, API, ISO,ISA, NACE, ASME and many other organizations. End users are also requesting consistent research and improvement on current practices, including testing and approvals. One way to ensure compliance is for the industry to conduct a survey of all valve manufacturers across the globe to validate that they have met the fugitive emissions requirements during the design phase with proper allowable code dimensions and the use of braided packing.

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