February 28, 2019
On December 6, 2018, at a New Jersey Department of Environmental Protection (NJDEP) regulatory update meeting, one of the topics discussed was the inclusion of formaldehyde in the calculation of volatile organic compound (VOC) emissions from spark ignited internal combustion (IC) engines which combust gaseous fuels including Natural Gas, Landfill gas and Biogas according to a February 5, 2019 report from ALL4 Inc.
Incomplete combustion of these fuels in IC engines leads to products of incomplete combustion (PIC), which we might often think of as carbon monoxide (CO). However, formaldehyde is also a PIC and was identified as having a high air toxic health risk in New Jersey.
Some health risks linked to formaldehyde include short-term respiratory issues such as coughing and chest pain and in the long term, exposure to formaldehyde increases the risks of respiratory cancers. NJDEP has taken a proactive approach and already issued notification letters to facilities clarifying that formaldehyde emissions must be included and properly accounted for in VOC emissions.
Current stack testing methods used to determine VOC emissions (e.g., U.S. EPA Method 25A, Method 18) are not designed to quantify formaldehyde emissions. However, U.S. EPA Method 323 or Method 320 may be used to determine formaldehyde emissions. The takeaway from this is that the stack testing methods used to determine total VOC emissions could bias the total VOC emissions low when formaldehyde is present in the exhaust stream. Formaldehyde is also not included in the current VOC emissions standard found in Table 1 of 40 CFR Part 60, Subpart JJJJ (Standards of Performance for Stationary Spark Ignition Internal Combustion Engines).
Moving forward, NJDEP is now requiring VOC emissions from combustion of gaseous fuels in IC engines to be calculated as the sum of nonmethane hydrocarbons (NMHC) and formaldehyde.
NJDEP estimates that in 2017, 96% of the formaldehyde emissions from stationary sources in New Jersey resulted from the combustion of natural gas, landfill gas, or biogas. When NJDEP reviewed stack tests on engines which combust landfill gas and natural gas, it was observed that formaldehyde emissions from IC engines varied widely and could represent the majority of total VOC emissions depending on the IC engine.
NJDEP has already required that all facilities must complete a permit modification to adjust for this limit no later than 90 days before the current permit’s expiration date. In the future, IC engines which combust a gaseous fuel and require stack testing will be required to conduct formaldehyde testing to properly quantify VOC emissions in New Jersey.
If you believe your IC engine now exceeds permitted VOC limits with the inclusion of formaldehyde emissions, it may be time to consider adding a control technology to ensure compliance with your limits. NJDEP found through stack testing that up to a 96% reduction in formaldehyde emissions is achievable in natural gas IC engines when using an oxidation catalyst (CO emissions also decreased by up to 98%). Another option for combusting landfill gas is to implement more stringent pre-combustion siloxane controls which will reduce the risk of incomplete combustion.
What this means to you
NJDEP is now requiring VOC emissions from combustion of gaseous fuels in IC engines to be calculated as the sum of nonmethane hydrocarbons (NMHC) and formaldehyde. NJDEP found through stack testing that up to a 96% reduction in formaldehyde emissions is achievable in natural gas IC engines when using an oxidation catalyst (CO emissions also decreased by up to 98%).