4 The record articles

The Ethylene MACT – An Air Quality Compliance Marathon

Posted: March 24th, 2016

Author: All4 Staff 

Over the years, ALL4 has chronicled the slow and not always steady regulatory development process in multiple blogs, articles, and presentations. For me, as the Air Toxics Knowledge Area Leader for ALL4’s RegTech Operations Group, I am responsible for tracking air quality regulatory and technical information, and then disseminating it throughout the company. In this role, I spend the majority of my time on the National Emission Standards for Hazardous Air Pollutants (NESHAPs; 40 CFR Part 63), and lately, with the Risk and Technology Review (RTR) program. For a refresher on the RTR program, our August 2014 article is a good place to start.

When economic drivers coincide with regulatory drivers such as the RTR program, we see growth opportunities, and ethylene production was a prime example in 2015. With respect to economic drivers, the ethylene production growth trend is tied to cheap and abundant natural gas. Though domestic oil and gas development has slowed considerably in 2016 due to lower prices, growth is expected to resume as supply and demand dynamics reach equilibrium in the coming years.  Growth in the oil, gas, and petrochemical market is expected to continue along the U.S. Gulf Coast and in the Northeast and mid-Atlantic U.S., which contain the Marcellus and Utica shale formations.  Industry publications consulted for this article, such as Petrochemical Update1 and various Daily Alerts published by the American Fuel & Petrochemical Manufacturers (AFPM) compare and contrast the advantages of ethylene production in these portions of the country based on infrastructure, environmental regulations, and workforce availability. The Northeast/mid-Atlantic U.S. regions are mature markets for petrochemical production. However, their aging infrastructure lags behind the Gulf Coast such that the cost to build an ethylene plant in the Northeast/mid-Atlantic region is expected to be $1 to $2 billion greater than a comparable plant on the Gulf Coast. Insufficient road and rail access are the primary factors driving this cost difference in the Northeast/mid-Atlantic U.S.  For reference, Petrochemical Update estimates that the construction of a 1.0 million tons per year ethane cracker (which is the nucleus of an ethylene plant) at a brownfield site in the Northeast/mid-Atlantic U.S. would cost approximately $1.61 billion, with another $1 billion likely required for site development at a greenfield location.

This influx of growth is coinciding with increasingly complex air quality regulations, including, but not limited to: the recently lowered ozone National Ambient Air Quality Standard (NAAQS); RACT 2 in Pennsylvania; and, the ongoing development of an updated Ethylene MACT standard (40 CFR Part 63, Subpart YY). With the scale of economic investment required for an ethylene plant, the air quality regulatory permitting requirements for such a facility often are the critical path for a project. New Source Review (NSR) permitting, which will require control technology analyses; the implementation of stringent emissions limits; purchasing emissions offsets for projects located in nonattainment areas; and modeling; will be part of most, if not all, ethylene projects. For an appreciation of the value that ALL4 will bring to a project, consider the fact that air permitting services typically are much less than 1% of a project’s capital budget. However, without the air quality permit in hand, construction of the plant cannot start. For even more perspective, think about this: ALL4 understands that in some industry sectors, bank funding for large capital projects will not be approved until the air quality permit has been issued!

In an article last year, we discussed the status of an Information Collection Request (ICR) for the Ethylene MACT. The ICR process for the Ethylene MACT continues (slowly but steadily) and the next component of the process (Component 2) is underway. The remainder of this article will focus on what is next for the Ethylene MACT ICR, and how ALL4’s experience with the ICR process (and beyond) can make the process more bearable.

Ethylene MACT ICR

In 2015, the U.S. Environmental Protection Agency (U.S. EPA) completed Component 1 of the Ethylene MACT ICR, which focused on source category characterization with respect to the emissions inventory, as well as data collection of site-specific information on existing ethylene production units. In 2016, U.S. EPA will launch Component 2 of the ICR, with a focus on emissions testing. Component 2 is under development as of the date of this article, and a draft has been issued to industry and non-government organizations (NGOs) for review and comment. The current plan for Component 2 is to complete emissions testing by November 30, 2016. The focus of the testing program will be ethane cracking furnaces, including the decoking stacks. What is interesting about this testing focus is that while ethane cracking furnaces and associated decoking operations are included as part of the Ethylene MACT-affected source category [40 CFR §63.1103(e)(1)(i)], the emissions of hazardous air pollutants (HAPs) from ethane cracking furnaces, including emissions during decoking operations, are not subject to the control requirements specified in 40 CFR §63.1103(e)(3).  According to §63.1103(e)(3), organic HAP emissions must be controlled by meeting the applicable requirements specified in Table 7 to Subpart YY. Under Subpart YY, organic HAP means the following compounds listed in Table 1 to 40 CFR Part 63, Subpart XX:

  • Benzene
  • 1,3-Butadiene
  • Cumene
  • Ethyl benzene
  • Hexane
  • Naphthalene
  • Styrene
  • Toluene
  • o-Xylene
  • m-Xylene
  • p-Xylene

Based on these recent actions, all signs appear to be pointing to the development of new emissions standards for ethane cracking furnaces. This does not seem overly complicated until you actually consider the operations of an ethane cracking furnace. Ethane cracking furnaces typically cycle in multiple operating modes:

  • Ethane cracking: The normal operating mode of the unit during which ethylene is being produced by cracking ethane.
  • Cold startup and shutdown: This mode covers both the operation of the unit when it is initially started up following a turnaround and the period following feed being taken out of the unit until it is off-line.
  • Decoking: During the ethane cracking mode, coke is formed within the radiant coils. Coke build-up eventually leads to high tube wall temperatures requiring decoking of the furnace. Every 30 to 60 days a furnace will go through decoking cycle, which will last for approximately 24 to 48 hours. The coke buildup is removed by injecting steam into the radiant coils while increasing the concentration of air to achieve controlled combustion of the coke in the furnace tubes.
  • Hot steam standby: Once a furnace has been decoked, it is placed into hot steam standby until it is needed for cracking [i.e. one (1) of the other furnaces requires decoking].
  • Feed in/Feed out: As part of the process of bringing a furnace down for purposes of decoking or maintenance, the furnace’s firing rate is reduced to a point where the feed to the furnace can be stopped. Similarly, when a furnace is being brought back online from hot steam standby, there is a period during which the firing rate is increased prior to when feed is placed into the furnace. These periods are referred to as feed in and feed out.

A review of recent air quality permit applications for ethylene production facilities indicates that best available control technology (BACT) emissions limitations for criteria pollutants have been established for the various operating modes of ethane cracking furnaces. Contrast this to HAP emissions, which to date are typically based on U.S. EPA AP-42 emissions factors for natural gas combustion. The lack of HAP emissions data for ethane cracking furnaces will be addressed by Component 2 of the ICR. The emissions data could then be used to set organic HAP emissions standards for one (1) or more of the operating modes of ethane cracking furnaces in the forthcoming Subpart YY.

ICR Experience

ALL4 has been involved with the testing components of multiple ICR efforts for MACT standards (and otherwise) in various industry sectors. While we do not conduct the testing personally (though many on our staff have performed stack testing throughout their careers), we often lead the development and execution of testing on a programmatic basis (identifying the range of operating conditions to be tested; identifying the critical process data to monitor and record; preparing test plans and protocol for submittal and approval by agencies; providing on-site testing program oversight; and reviewing, interpreting, and preparing test program results for submittal). We also have prepared and submitted comments on the ICR process on behalf of clients and/or industry trade organizations, which is where we find ourselves right now with respect to Component 2 of the Ethylene MACT ICR process.

So where do we go from here? If you are a facility affected by the Ethylene MACT ICR, reach out to us to discuss what is being requested from you, and how to make sense of it. There are significant data management obligations through this process, and while stack testing companies will obtain that data for you, ALL4 is prepared to evaluate and understand the implications of the data that will be reported to U.S. EPA, your state agency, and the general public. The emissions and related data that are being collected now could impact future projects at your (or your company’s) operations, and it is essential that you understand what is occurring now in other regulations such as the Petroleum Refinery MACT that could be setting a precedent for ethylene production plants. With our experience in these sectors, we can provide the proper perspective from an air quality regulatory compliance vantage point that will make this marathon feel like a 5K race.


[1] Northeast US Petrochemical Projects: Seize Opportunities, Confront Challenges


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