Activated Carbon Bed Vapor Recovery Units

The transportation of petroleum liquids (crude oil, gasoline, other refined products) and organic chemicals is often done by tank truck, rail tank cars and marine barges and ships. Also, gasoline is delivered by tank truck to service stations. The loading of products to the transportation vessels and service station tanks results in evaporative losses of volatile organic compounds (VOCs) that may be required to be controlled to reduce emissions to the atmosphere.

The VOC evaporative losses generated during loading operations are a function of the liquid’s vapor pressure, temperature, vapor chemical composition and loading method used. Equations in AP-42, Chapter 5, Section 5.2 can be used to estimate VOC emissions from loading petroleum liquids.

One method used to control these VOC emissions is to use Activated Carbon Bed Recovery Units.

Activated carbon bed recovery units are vapor recovery systems used to recover VOC vapors generated from organic liquids loading operations. The process uses activated carbon as the adsorption media to remove and recover volatile organic compounds (VOCs) from gas/vapor streams. Activated carbon bed adsorbers are used at crude oil facilities, petroleum refineries and chemical manufacturing facilities.

Process Description

Fixed-bed, regenerable carbon bed recovery units use adsorbers that can operate intermittently or continuously. Typically, two or more activated carbon beds are used. One bed is used for recovery/removal of VOC vapors and one or more beds will be in standby mode or in regeneration mode.

The cycle for typical treatment consists of the following.

1. The VOC stream flows to an activated carbon bed where adsorption of VOCs occurs.
2. Once the activated carbon bed is saturated with VOCs, the VOC stream will be sent to a standby/regenerated carbon bed.
3. The saturated activated carbon bed is then regenerated. Regeneration can be accomplished by:

• Vacuum regeneration using a vacuum pump to lower the pressure below the vapor pressure of the adsorbed VOC. This causes the VOC to boil off from the adsorbent. This is a preferred method used by many systems. Dry vacuum pumps are often used due to their reliability and lower contamination of recovered vapors by lubricating oils.
• Thermal swing regeneration can use steam to increase the temperature of the bed to desorb the VOC molecules from the activated carbon bed. Steam flow is normally in opposite direction of treated gas flow.

 

Fixed-bed regenerative adsorbers designed to operate continuously consist of two or more carbon beds where at least one regenerated carbon bed is available for adsorption/recovery continuously

allowing the emissions source to operate continuously.

Canister-type adsorber units are often used to control to lower flowrate and intermittent gas streams. For these units, one or more smaller cannister are used to adsorb the VOCs with the saturated cannisters sent offsite for regeneration. In gasoline applications the life cycle is between 10 to 15 years. For crude oil loading applications expected replacement would range from 6 to 10 years.

Applications

Activated carbon bed vapor recovery systems are commonly used for the following listed below. These applications are typically intermittent uses.

• Loading terminals (oil and gas production, rail, land-based on marine storage) of crude oil, gasoline, diesel and organic chemicals
• Oxygen removal for tank truck or rail loading of crude oil and condensate where vapor recovery used to compress vapors and send them to sales pipeline or system.
• Bulk gasoline loading facilities
• Retail gasoline stations

Control Efficiencies

Properly designed, operated and maintained carbon adsorber systems can attain VOC removal efficiencies equal to or greater than 99%.

Benefits

• Increase profit from product recovery
• Measurable return on investment (ROI): 12 to 24 months depending on throughput
• Non-destructive control technology so no NOx, CO, CO2 or SO2 generated
• Lower cost
• Suitable for waste streams containing wide range of VOCs

Disadvantages

• Not effective for VOCs with high polarity (e.g., alcohols, organic acids)
• Not effective for highly volatile compounds (e.g., vinyl chloride)
• Reduced capacity in high moisture applications
• Fire hazard if used with oxygen bearing compounds or VOCs having high heat of adsorption

Conclusions

Vapor Recovery Units (VRUs) are one of the most efficient ways of capturing the vapors generated from standard oil and gas production processes and generating revenue from this by-product as a result. Since 1980, our Jordan Technologies division has designed, manufactured and serviced VRUs across multiple industries, including liquid-loading terminals, as well as retail gasoline stations.

For terminals (rail, marine storage) loading as well as retail gasoline station unloading applications, an activated-carbon based Vapor Recovery Unit is preferred. While our VRU designs continue to evolve based on constant field feedback from our service technicians, customers, and changing industry requirements, we rely primarily on dry vacuum pumps technology (manufactured by industry leaders HORI and Busch) due to its overall reliability and lower contamination of recovered vapors by lubricating-oils and glycol.

Cimarron – Who We Are

The company engineers and manufactures environmental, production and process equipment for the upstream, midstream and downstream energy industries, as well as environmental control solutions for biogas at wastewater facilities, digester tanks and landfills.

Cimarron offers our customers the know-how and environmental expertise to meet the environmental standards of today and tomorrow. Cimarron is committed to bring value to the Energy industry and their shareholders based on our financial strength, experienced personnel, and engineering capabilities.

As a company, we thrive every day to make a difference through innovation (e.g. ESG), customer focus, and operational efficiency. In addition to being present in all major regions in the US, Cimarron serves more than 45 countries around the world, ranging from offshore to desert. From key operational centers in the United States, Italy and the United Arab Emirates, Cimarron offers ongoing service and support through its own field service personnel and strategic third-party partners, creating a cleaner environment for our customers and their shareholders.

Since its founding in the mid-1970’s in Oklahoma, the company’s product offering has expanded from production equipment to include the largest line of environmental solutions that capture or incinerate fugitive vapors. With the acquisitions of HY-BON/EDI in 2019 and AEREON (including Jordan Technologies) in 2020, Cimarron has added strong brands, products, and services to its portfolio.

The Jordan Carbon Bed VRUs can be designed to recover up to 99.9%+ of VOCs (or as low as 0.15 mg/l or 150 mg/nmg) generated during product loading with no NOx. The VRUs turn vapors back into sale-able gasoline during truck loading, marine loading, tank breathing or retail gas station truck unloading applications. #CreatingACleanerEnvironment

Find out more at www.cimarron.com.

+1 844-746-1676 | sales@cimarron.com

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