Vapor recovery towers (VRT) were originally implemented into oil and gas production facilities to prevent oxygen from entering into the sales line. This was achieved by installing a VRT in between the production tanks and the separator while capturing the VOC emissions upstream of the tanks. Typically they operate in conjunction with a vapor recovery unit. Whether a VRU is installed within the process or after, EPA refers to them as “process equipment,” therefore allowing the owner/operator to discount the total VOCs emitted from storage vessels and rerouted and captured by a VRU when determining affected facility status.
Today, OTA provides top of the line vapor recovery units and the industry standard VRT, but is proud to announce our patent pending VRT-MAX. Both models are designed to improve vapor recovery efficiencies and prevent oxygen from entering into sales line; however, there are definite improvements by utilizing a VRT-MAX. OTA’s MAX vessel is designed to MAXimize flashing and simulate working and breathing losses that would otherwise occur at the storage vessel facility, possibly resulting in an affected facility status. The oil has time to stabilize at a minimum retention time of 30 minutes, ensuring that maximum vapor breakout occurs.
The max VRT operates reverse from the standard VRT with a bottom-to-top product flow direction. The liquid enters the vessel at a lower pressure than the separator, therefore gas vapor will break out of the liquids or “flash” will occur. As the product enters through the bottom of the vessel, there are internal coils that will provide a rise in temperature from utilizing the heat off of a compressor’s discharge. This rise in temperature (typically 30-40 degrees above ambient) and decrease in pressure will cause the flash from the liquids to intensify as the product spirals up. An additional benefit to this style of VRT would be that operators can possibly run their heater treaters at a lower temperature and save on fuel gas by using the recycled heat generated from the compressors discharge.
By creating the worst case for the liquids potential to emit scenario, you have the ability to produce and capture more flash emissions than before. The space above the vessels liquid level in a VRT is where these rich vapors are stored. The vapors are then routed to the VRU for recovery. This process keeps the flashed gas from reaching the tanks which also helps minimize fugitive leaks from tank hatches and enardos.
These vessels come in various sizes based on liquid production and tank height. OTA’s VRTs can be used in singular or dual setups. It is recommended that a dual VRT be utilized when high VOC content is entrained in water samples in order to maximize capture efficiency and eliminate the need for control devices such as a combustor.
Be sure to contact your OTA representative to find out which VRT design is right for your facility @ (972) 835 – 6383 or by e-mail at sales@OTACompression.com.
