(Updated November 13, 2019)

1. What is a VRU?

A VRU, or Vapor Recovery Unit, is a compression system used to collect and compress low volume gas streams for injection into the suction of a larger compressor, a meter run, a local site fuel gas system or directly into a gas gathering line. Mechanical VRUs consist of a driver motor or engine that supplies the power to the compressor. They are often used by oil and gas operations to recover vent gas.

Existing federal and state air quality and permitting regulations require oil and gas (O&G) production facilities to control emissions from crude oil, condensate and produced water storage tanks. The primary federal EPA rules for storage tanks (and other O&G sources) are in NSPS OOOO and NSPS OOOOa. These NSPS rules affect facilities construction after August 23, 2011. State environmental regulatory agencies have their own standards and permitting regulations that require storage emission controls for existing and new facilities.

These federal and state air permitting rules require the storage tank vapor controls systems to be designed and operated such that emissions are continuously controlled. Inadequately designed storage tank emission control systems that result in venting of VOCs are a focus of the EPA.

The EPA intends to collect emission inventory related data from the oil and gas industry to gather information that will be used to develop emission standards (reductions) for existing facilities. 

The New Source Performance Standards in 40 CFR 60 Subpart OOOO and OOOOa exempt existing oil and gas facilities that were constructed on or prior to August 23, 2011 (and not modified or reconstructed after that date). These “existing” facilities are the target of this data collection.

The method that will be used to obtain the data is an Information Collection Request (ICR).  The EPA is not required to go through rulemaking to request this information. EPA has authority under Section 114 of the Clean Air Act to request the information provided the request is approved by the Office of Management and Budget (OMB). 

(Updated January 2, 2020)

The federal EPA rules regulating VOC emissions from oil and gas operations are known as New Source Performance Standards (NSPS) OOOO and OOOOa. NSPS OOOO affects O&G gas facilities constructed, modified or reconstructed after August 23, 2011, and on or before September 18, 2015. NSPS OOOOa affects facilities constructed, modified or reconstructed after September 18, 2015.

There are some pending changes to NSPS OOOO/OOOOa regarding

• Regulation of methane
• Applicability of the rules to transmission and storage facilities
• Frequency of fugitive leak monitoring at well sites and compressor stations
• Well site pneumatic pump standards
• Requirements for certification of closed vent systems by a professional engineer

This summary focuses on requirements for the oil and gas industry upstream of gas processing facilities.

This rotary screw compressor package was designed for a customer for an offshore application in the Gulf of Mexico. Utilizing an encapsulated screw compressor design (Rotorcomp NK series), HY-BON/EDI was able to minimize the overall footprint of the Vapor Recovery Unit.

(Updated 28 November 2019)

The oil and gas (O&G) industry uses Leak Detection and Repair (LDAR) programs to reduce methane and VOC emissions from their operations. Existing federal and state regulations require LDAR at O&G production facilities. Also, voluntary industry programs are an integral part of the effort to reduce methane and VOC emissions form O&G facilities and equipment.

Existing Source Regulations and Information Collection Requests (ICR) for Oil and Gas Sources

On March 10, the EPA announced their plans to develop methane rules for existing sources located in the oil and gas production, processing and transmission segments under Clean Air Act Section 111(d). Building off of proposed regulations requiring methane reductions from new and modified sources (i.e., NSPS Subpart OOOOa for oil and gas sources), EPA is now developing standards for existing sources as well (not entirely unlike the process used for developing requirements for existing electric generating units under the Clean Power Plan).  EPA announced their intent to "move quickly" and to "start immediately" to develop regulations controlling methane emissions from existing oil and gas industry sources.

The Bureau of Ocean Energy Management (BOEM) is proposing to modify its air quality regulations applicable primarily to operations in the Outer Continental Shelf (OCS) of the Gulf of Mexico and Alaska’s Arctic waters.

(Updated December 18, 2019)

Heater treaters can be significant sources of “flash gas” from oil and gas production facilities. Flash gas is natural gas that is released from a well stream when the liquid undergoes a pressure drop or when the liquid’s temperature is increased. In a heater treater, the crude oil/condensate and produced water experience a pressure drop and a temperature increase. The greater the pressure drop and operating temperature, the greater the amount of flash gas generated per barrel of oil throughput.