June 16, 2015
Tanker truck loading of crude or condensate presents unique challenges for producers in the area of safety and regulatory compliance, operating integrity and economic return. AEREON’s patent pending Air Defender product line represents proprietary technology based on carbon bed adsorption with proven performance characteristics superior to other conventional alternatives.
The Air Defender:
- Minimizes VOC emissions and the buildup of undesirable combustible gases.
- Eliminates excessive oxygen introduction in storage tanks and downstream operations.
- Provides an incremental economic return by increasing liquid recovery and lowering costs.
Conventional technologies have not kept pace with the rapid pace of development of oil and condensate rich shale production and the growing reliance on tanker trucks for getting product to market. Recent history has demonstrated that operators are suffering economic losses or taking on unnecessary safety and operational risks, including: excessive VOC emissions; unintentional induction of oxygen into volatile storage tank head space creating safety concerns; and rising operational integrity downstream in pipeline and compression assets.
Data has been collected from existing truck loading sites using conventional technologies to determine VOC and oxygen levels emitted from truck vapors. Additional information has been collected comparing various technologies that, to date, have offered the best solutions for safe truck loading. This data is used to compare the efficacy of AEREON’s carbon bed recovery solution, Air Defender.
Three Points of Concern with present methods of loading:
- Truck Vapor Displacement by venting
In all loading situations saturated hydrocarbon vapor in the headspace of the truck container must be displaced by the incoming liquid during the loading process. Often this vapor is vented into the atmosphere. As shown in table1, in a typical 200 barrel load out, these displaced vapors can contain on average 78 lbs. of VOCs. If a facility loads one truck per day, the total annual vented emissions would be over 14 tons. These levels of emissions can result in operators being in violation of air permits which in turn would require re-permitting for a larger emission value. Vented vapors are also explosive and contain harmful carcinogenic compounds which put both people and facilities at risk.
An alternative to simple venting is to balance load. This process directs the displaced vapors, containing a mixture of VOCs and air, from the truck that is being loaded back into the newly available head space of the unloaded liquid storage tank. While this minimizes the risks of VOC emissions and the formation of explosive vapor clouds, it introduces a different risk-excessive oxygen ingestion which may negatively effect field compression and pipeline operations. As illustrated in Table 2, the oxygen content in these displaced vapors are sent back to the storage tank via vapor balancing and may contain on average 126 ft3 of pure oxygen from a 200 barrel truck load. High oxygen levels in natural gas collection systems can impair operation and cause compressor stations to shut down. This in turn can cost tens of thousands of dollars in lost revenue.
- Burning vented truck vapors
A third method of VOC removal from tank truck loading operations is to direct the displaced vapors to a combustion device such as elevated flares, enclosed flares or natural draft thermal oxidizers. Extreme caution must be used in selecting the appropriate equipment to burn the waste vapors due to the nature of the loading operation itself. Without carful management, waste vapors could go through the explosive range. As with every truck load, specific loading rates could vary, ranging from no flow to full flow within minutes requiring assist gas to be supplied to the waste stream at all times in order to prevent flashback and potential explosions.
An alternative combustion product is an enclosed thermal oxidizer built for truck loading operation conditions. With the appropriate controls such as detonation arrestors, waste control valves and assist gas this can be a costly but viable alternative.
Appendix I provides an advantage/disadvantage table on types of recovery and combustion equipment. All facilities must be careful when deciding to install combustion to eliminate free venting or balance loading. Re-permitting issues for combustion can be costly and finding the available safe space for combustion can be a real estate problem.
The Air Defender
Overcoming the loading challenges operators face in today’s market requires a new technological approach. Combustion is frowned upon, permits lock in operators to set emission limits, oxygen ingestion can cause compressor station shut in and safety is a major concern. AEREON’s Air Defender offers an innovative solution to every stated issue.
Air Defender technology relies on 35 years of experience in building and supplying carbon bed vapor recovery systems worldwide for truck, rail and marine loading terminals to a majority of the largest oil companies. We have now created and introduced the first single carbon bed vapor processor (patent pending) that recovers VOC emissions and removes oxygen.
The fundamentals of Operations (Refer to Figure 1)
As a truck connects to the facility to load, a vapor collection hose is also connected to the truck for vapor recovery. As the truck fills with product, the displaced vapors are sent to the Air Defender carbon bed. In this stage of operation, the VOC are adsorbed on the carbon bed for further processing while the clean air, including oxygen, is emitted into the atmosphere.
Once the truck has completed loading, the carbon beds are cleaned by simple vacuum regeneration. The recovered, oxygen depleted, hydrocarbons that are removed from the carbon bed are then sent directly back as a recovered gas to the head space of the liquid storage tank facility as salable product.
The Jordan Results
The Air Defender is designed to recover all truck emissions (less methane) while removing oxygen from the vapor stream that enters the storage tank head space. The recovered gas products can then be sold as a clean pipeline quality natural gas that won’t shut in a compressor station due to high oxygen levels.
This “first of its kind” is a game- changer when it comes to vapor recovery at condensate and crude loading facilities. Thanks to its ability to achieve 99% VOC recovery (see table 3) and 98.8% oxygen removal (see table 4) without a flame, re-permitting is not an issue.
Our goal at Jordan is to provide a system that reduces safety concerns, cleans up the environment and turns those lost gases back to the bottom line. A pure and simple environmental solution is what we offer. For further information on how the Air Defender can be applied to your facilities please visit our contact us page or call us at 502-267-8344.