Vapor Control

Flare Gas Recovery, Vapor Recovery, Vapor Combustors, and more

flare gas recovery

Flare Gas Recovery (FGR) is the process of recovering the waste gases that would normally be flared, so they can be used as fuel gas elsewhere in the facility. This results in reduced emissions and cost savings.

Flare Gas Recovery Systems (FGRS) perform the following processes:

  • Isolating the flare header with a proprietary-design liquid seal or staging valve
  • Recovering normally flared gases and delivering them back into the facility so they can be processed and re-used as fuel gas
  • Removing liquids
  • Compressing gases up to a defined pressure level

A facility’s safety depends on properly integrating the Flare Gas Recovery System into the relief header and the flare system. The compressor skid is only one piece of the package – all components must be properly designed and built to ensure safe and reliable operation of the entire package. This is why it is so important to utilize the expertise of a company like Zeeco with Flare Gas Recovery and Flare System experience.

Typical FGR Sizing:

  • Flowrate Ranges: 0.1 to 10MM SCFD (11,100 Nm3/hr)
  • Pressure Ranges: 35 to 300 psig (20.7 barg)

Services Offered:

  • Engineering Studies – let us help you determine if a FGR system is right for your facility. Our engineers will recommend system sizing, compressor technology, and ancillary equipment. They will develop the cost estimate and evaluate the payback period to help you decide the economic feasibility.
  • Engineering, design, fabrication, supply, installation, and startup of FGR packages.
  • Field support after equipment startup.

Put Zeeco’s Experience to Work for You

Zeeco’s staff members have extensive experience in design, fabrication, and installation of Flare Gas Recovery Systems, along with a full range of vapor control, vapor combustors, and vapor recovery units (VRU). We can evaluate the existing flare system, including the normal flow to the flare, size the Flare Gas Recovery system, design the liquid seal drum, and recommend proper integration of all the equipment and controls for your specific application.


vapor recovery

Wherever liquids are loaded into trucks, ships, or rail cars, a vapor stream, laden with Volatile Organic Compounds (VOCs), is generated and must be controlled to prevent it from escaping into the atmosphere and creating both harmful emissions and lost product.

There are two primary methods for controlling these vapors, burning them in a vapor combustor unit (VCU) or recovering them in an activated carbon vapor recovery unit (VRU). Typically, a VCU requires less capital and can achieve very high VOC destruction efficiencies, but it will also generate other emissions, such as NOx, CO, and CO2. A VRU, on the other hand, requires more capital, can achieve similar equivalent VOC destruction efficiencies, but does NOT generate any other emissions and will recover approximately one to two gallons of product for every 1,000 gallons of product loaded. It is one of the few vapor control technologies with a payback.

Zeeco offers the industry's most advanced vapor recovery units (VRUs) that are tailored to meet your precise needs, which ensures maximum recovery of hydrocarbon vapors. We custom engineer our VRU’s for crude oil and refined products, at any flow rate and ambient conditions.


Standard systems for crude and refined products, including:

    • Marine loading terminals
    • Truck loading terminals
    • Railcar loading
    • Storage terminals

Key Features include:

    • State-of-the-art dry screw vacuum pumps
    • Modular design, which minimizes footprint
    • Simple operation
    • Low operating costs

VAPOR Combustors

Zeeco's fully automated Vapor Combustor Units (VCU) are primarily used to control the VOC laden vapors generated during the loading of crude oil and refined petroleum products into trucks, railcars and marine vessels. They are also used to control the vapors generated by the venting of petroleum storage tanks.  Zeeco's vapor combustors are fully enclosed, have automated temperature control, and can achieve VOC destruction efficiencies of up to 99.9%. These high-efficiency vapor combustors can operate on a wide range of vapors without smoke or visible flames. Units can be sized to fit the smallest truck rack to the largest marine loading systems. Flow rates up to 80,000 BPH or higher by combining multiple VCUs in parallel.


    • Destruction efficiencies up to 99.9%
    • USCG Certified Anti-Flashback Burners.
    • Dedicated, Variable Frequency Driven (VFD), air-assist fans deliver combustion air directly to each burner pack.
    • Burner packs can be staged to meet a wide range of operating requirements.
    • Automated dampers for more precise control of combustion air, which allows tuning of the VCU for optimal emission performance.
    • Designed for minimum pressure drop in order to ensure backpressure on truck rack is less than 18” W.C.
    • High turndown capability.
    • Smokeless performance from 0% to 100% operation.
    • Detonation arrestors on the vapor inlet line to prevent flashbacks into terminal piping.
    • Operation can be tied to loading operations to turn system on and off as needed.
    • PLC based control system with HMI for fully automatic flame ignition and monitoring
    • Standard emissions
      • - VOC DRE: 98% up to 99.9%
      • - NOx: 0.12 to 0.2 lbs./MMBTU
      • - CO: 0.1 to 0.5 lbs./MMBTU

biogas & landfill flares

Biogas flare systems are used to dispose of gases that are produced from decomposition of organic matter or biomass. Typical examples are gases produced from landfills, wastewater treatment (anaerobic digesters), or other biomass sources. Gases are typically mixtures of methane, carbon dioxide, small amounts of nitrogen, oxygen, hydrogen sulfide, and others. Biogas must be handled in a specific manner to ensure combustion to a high degree of efficiency. In addition, the possibility of oxygen in the gas mixture coming to the flare means flame arrestors and special flame arresting burners must be employed. Biogas can be burned to a high degree of efficiency in either an elevated flare or an enclosed ground flare system.


If your facility is an environmentally sensitive area where NOx emissions are tightly regulated, such as one of the EPA’s 8-hour ozone Nonattainment areas, then you will also need an ultra-NOx VCU.  Zeeco has developed the TriClean VCU, which is an ultra-low emission VCU that can achieve NOx emission of less than or equal to 15 ppm (0.018 MMBTU/hr.) and CO emissions of less than 10 ppm (0.01 MMBTU/hr.).

Exterior of Biogas and Landfill Flare System


Zeeco can provide combustion and emissions control solutions wherever hydrocarbon processing takes place. Customers can find our equipment and services in upstream, midstream, and downstream oil and energy processes.

We also offer products and support for other industries and applications such as tank/terminal loading and storage, pharmaceutical, carbon black, pulp & paper, steel, food processing, and more.