Three Phase Permitted Vapor Control

Three Phase Permitted Vapor Control

Portfolio Categories: Degassing, Odor Control, and Vapor Control.

Challenge 

Pacific Northwest customer need to take a >200′ D sour crude tank filled with several feet of sludge out of service. The sludge was to be processed via centrifuge in a location adjacent to a heavily used toll bridge. However, odor complaints from toll booth operators had the potential to result in customer having to pay daily bridge tolls for every car taking the bridge in by the local Air Quality jurisdiction . Bridge traffic is estimated at >40,000 cars per day. The potential  of an approximate $5 per car penalty fee, totaling nearly $200,000 a day, is an unacceptable result of this needed service. Envent Corporation was tasked with creating a robust vapor control solution ensuring compliance and eliminate the possibility of ANY odor complaints.

Solution 

Envent provided a three phase Permitted vapor control solution. The first phase of vapor control was implemented to manage vapors off the large diameter tank while in the initial degassing phase. Envent’s system was comprised of a recirculating scrubber (for H2S removal), along with a high flow thermal oxidizer. Phase two of vapor control consisted of redundant liquid / carbon / blower system which was manifolded to Permitted temporary tanks, mix tanks, centrifuge and associated hooch. Phase three of vapor control was to maintain a vacuum on the fixed tank as sludge was being removed with manways open after tank was degassed. Envent provided high flow vapor conveyance lines, 5,000 CFM blower and 5,000 CFM high flow carbon trailer.

Benefit

Envent Corporation provided the customer with a vapor control solution which managed to safely eliminate nuisance odors to the surrounding community as well as maintain 100% compliance, resulting in no fines.

 

 

Port of Brownsville, TX – Tank Degas

Portfolio Categories: All, Degassing, Marine Vapor Recovery, and Vapor Control.

Challenge

A customer at the Port of Brownsville was preparing a mid-sized high RVP gasoline tank for an API 653 inspection. The tank, which was fed by a pipeline, was assumed to be empty of product. However, upon further inspection by the client and their tank cleaning contractor, it was discovered that over one foot of gasoline product remained at the bottom—concentrated near the sump and water draws. This unexpected finding introduced potential vapor hazards, compliance risks, and scheduling delays.

Solution

Envent Corporation worked closely with both the customer and the cleaning contractor to provide continuous, 24/7 mobile degassing and vapor control services. Our thermal oxidizer systems and expert operators ensured safe handling of petroleum vapor control throughout the operation.

  • Envent deployed mobile equipment configured to manage low and high BTU vapor streams while reducing vapor concentrations to meet the facility’s air permit limit of <10% LEL

  • We applied vapor scrubbers and thermal oxidation technology tailored for high-RVP gasoline applications

  • Our team continuously monitored vapor levels and adjusted the system to maintain control, ensuring full regulatory compliance under local and federal guidelines

Benefit

Despite a few minor setbacks during execution, Envent’s team adapted quickly, upheld safety standards, and delivered the project ahead of schedule. The collaboration between Envent, the facility, and the cleaning contractor allowed the job to be completed safely and efficiently.

This project highlights Envent Corporation’s expertise in tank degassing for refineries, pipeline vapor control, and turnaround vapor control. Backed by the largest fleet of mobile thermal oxidizers, our team remains committed to our core priorities: Safety, Compliance, and Quality of Service.

 

West Texas Terminal – 3 Tank Vapor Control

Portfolio Categories: Case Studies and Vapor Control.

Challenge

A large Oil and Gas customer needed to perform maintenance on 3 tanks in one of their West Texas terminals. The majority of the maintenance was focused on removing and replacing the shell-side mixers. The problem was that those same tanks were critical to their day to day operations, meaning that the turnaround time from landing the roof to refloating it would need to be as short as possible. Historically, the terminal had taken the tank out of service degassed and cleaned them before performing the maintenance. This process was not ideal since the tanks would come up on API 653 inspection in about a year or so, and performing the entire work twice was not economically viable. The site was also restricted by a very strict environmental permit, along with having tanks with an average H2S concentration of about 2,500 ppm. A solution for a quick and safe manner to perform the maintenance was needed.

 

Solution

Envent worked with the site’s engineering team in planning and preparing a method to safely control vapors from the tanks during the stripping of the tank’s product, the change out of the existing shell-side mixers, and during the recommissioning of the tanks. A process was engineered in order to maximize the vapor draw from the tank’s existing roof connections during the maintenance phase, this allowed the customer to only lower the liquid volume in the tank enough to perform the maintenance instead of fully emptying the tank. This enabled the customer to liquid balanced the other two tanks and avoid any temporary storage. Envent utilized a thermal oxidizer capable of an outstanding 10 million BTU per hour load, along with a Stainless Steel Recirculating Scrubber.

Benefit

The customer was able to perform the needed maintenance on three tanks all in record time. Where in the past similar maintenance had taken a (1) tank one and a half week s to complete; all three tanks were completed in around 10 days total. The environmental impact was much less than ever expected; the thermal oxidizer enabled a 99.99% destruction efficiency of hydrocarbon vapors. Envent’s mobile scrubber also removed all H2S in the vapor stream prior to combustion; this not only kept the maintenance crew safe from any exposure but also kept the Customer within their environmental permit.

Depressurization of a Panhandle LPG Pipeline

Portfolio Categories: Case Studies, Degassing, Turnaround Services, and Vapor Control.

Challenge

Envent was challenged with depressurizing a propane line, within the confines of a gulf coast refinery.  The line measured over 2 miles, was above 200 psig, and was full of liquid propane gas.  Envent needed to ensure the pipeline was cleared and ready for Hotwork within a 2 day time frame due to inclement weather from an approaching tropical storm.  To further complicate matters, the hosting refinery was in turnaround mode and lacked critical support to prolong or accommodate changes in schedule.

 

Solution

Envent deployed a series of LPG vaporizers,  multiple skid regulators, ASME rated liquid knock out pots and the largest mobile thermal oxidizer in the industry; our EMECS 70.

 

Benefit

Envent was able to depressure and N2 purge the pipeline to 0% LEL within 8 hours, from start to finish.  Envent exceeded the goal to degas within the tight time frame; this allowed the customer to perform the maintenance required in record time.

The same pipeline split in two projects:

Our higher pressure >200 psig and 2 mile pipeline completed in less than a shift.  A shorter 3/4 mile long 115 psig pipeline, cleared by a competitor, took 4 full days to complete.

 

 

California Refinery Barge Loading

Portfolio Categories: All, Case Studies, Marine Vapor Recovery, and Mobile Water Treatment.

Challenge

A California refinery terminal needed to load gasoline, ethanol, and other high vapor pressure materials (classified as MVR products) onto barges. These Marine Vapor Recovery (MVR) products require vapor control during marine loading to comply with stringent USCG regulations (33 CFR 154 Subpart P).

However, the terminal lacked any fixed vapor recovery equipment at the dock. Without a temporary vapor control solution, the refinery risked losing substantial revenue opportunities from the inability to load and sell these valuable products.

Solution

Envent Corporation provided a USCG-certified Marine Vapor Control System (MVCS), specifically engineered to meet all marine vapor recovery requirements. The solution included:

  • The industry-leading EMECS (Envent Mobile Emission Control System) thermal oxidizer to destroy vapors safely and in full compliance with EPA BACT standards

  • Envent’s Dock Safety Unit (EDSU) to ensure safe vapor handling at the marine loading interface

  • Full system design and installation in accordance with USCG 33 CFR 154 Subpart P, including pipeline sizing, PRV/VRV requirements, safe distances, and equipment certification

Envent’s engineers and project managers coordinated with site personnel, crafts, and regulatory bodies to ensure seamless installation, testing, and operation. A third-party USCG-certified inspector provided a compliance certification letter, now maintained in the terminal’s regulatory files.

Benefit

With Envent’s mobile vapor control solution, the refinery terminal successfully loaded MVR products at a rate of 7,500 BBL/hr onto ships and barges, unlocking significant operational and financial benefits:

  • Maintained full regulatory compliance with USCG marine vapor recovery regulations

  • Increased throughput and profitability with faster, more efficient loading capabilities

  • Avoided capital investment in permanent infrastructure through Envent’s temporary vapor recovery solution

  • Enhanced operational flexibility to continue marine shipments of gasoline, ethanol, and other high-BTU products

Over the next few years, this project is expected to generate millions in additional revenue for the terminal—further solidifying Envent’s reputation as the industry leader in mobile marine vapor control systems, thermal oxidizer technology, and turnkey emission compliance solutions.

Port Arthur Refinery – H2S Scrubber Control

Portfolio Categories: All, Case Studies, Vapor Control, and Vapor Scrubbing.

Challenge

A customer was facing EPA fines in the tens of thousands of dollars per day for the release of H2S and VOC’s to atmosphere from a tank not permitted to contain H2S-laden material. The customer reached out to Envent to solve the problem within a short deadline of three months.

 

Solution

Envent was able to design and construct a specialized vapor control system that stripped the vapors of a sticky aerosol residue and pull the H2S-laden vapors through a bank of Envent ESCRUB 1000 circulating scrubbers. This system operates continuously at 1,000 CFM and treats 7,000 PPM of H2S.

 

Benefit

For nearly three years, Envent has operated this system with ZERO breakthrough of H2S and ZERO safety incidents. Envent crews have operated this system safely and efficiently, day and night, 24/7/365. The onsite Envent technicians have been able to optimize the system to utilize as few consumables as possible, lowering the costs to the customer. The customer was able to avoid EPA fines and now has the time to design and construct a permanent process unit slated for construction in 2020.

RTO Breakdown Emergency Mobile Replacement

Portfolio Categories: Case Studies and Vapor Control.

Challenge

West Coast customer challenged Envent to create an immediate temporary solution which would enable them to continue production during the 1.5 month lead time it would take to manufacture, transport, and install their new system.

                               

Solution

Envent supplied a Temporary Air Handling and Treatment System consisting of three separate trains of custom built Envent paint particulate filters followed by three 14,000K lbs. / 20,000 CFM carbon units. The particulate filter housings were equipped with pressure differential gauges making it easy to anticipate change outs. The high flow carbon units were equipped with multiple air sample ports providing the opportunity to anticipate potential breakthrough. Envent also supplied a nitrogen source due to possible reactions and overheating. Envent’s treatment system was designed to safely enable high flows continuously during potential recharging events.

 

Benefit

Envent’s vapor control solution and project management support enabled this West Coast customer to meet their aggressive production goals during this short outage for less than 1% of their potential liability.  
 

Golden Triangle Refinery Turnaround

Portfolio Categories: Case Studies, Degassing, Odor Control, and Turnaround Services.

Challenge

An 80,000 bbl. /day crude distillation unit underwent a month long planned shutdown in order to perform maintenance on their exchangers, and pressure vessels. The shutdown began with the de-inventory and decon of the unit, often heralded as an unavoidable slow measure. Depressurizations, high flow nitrogen sweeps, and liquid deinventory can lead to many unanticipated delays. Due to the relatively small size of the unit, footprint was a concern, which added an additional layer of hazards.

Solution

Fortunately for this refinery, Envent designed, engineered, and executed a system that mitigated any potential hazards, as well as effectively and efficiently decreased decon time by three whole days. Liquid carryover was mitigated by adding low point drains in strategic sections of the process lines. Barriers were erected to limit foot traffic through the small footprint. Hose diameters were upsized to reduce pressure drop and allow for higher flows during depressurizations. Additionally, an injection port was installed into the process line to allow for enrichment of high nitrogen flows. These and many other factors contributed to Envent’s success in this turnaround, which shaved off three entire days from the refinery’s schedule!

Benefit

The refinery Turnaround planning team, anticipated at least seven days of runtime with Envent equipment. However, once process began to flow into the thermal oxidizers, higher flows were achieved. This allowed the refinery to complete their objections within four days! Once shutdown was complete, all equipment was removed, cleaned, and out of the refinery within 48 hours of job completion. A refinery turnaround lead summarized it best,” I want to express my appreciation for a job well done! The Envent team showed professionalism and a spirit of team work that allowed us to turn over the unit ahead of our original schedule…Thank you and we look forward to upcoming projects with Envent.”

Gasoline Product Pipeline Degassing

Portfolio Categories: Case Studies, Degassing, and Vapor Control.

Challenge

A West Coast midstream oil company needed to degass 20 miles of pipeline containing crude oil and hydrogen sulfide (H₂S) vapors in preparation for scheduled pipeline maintenance and repair. The pipeline ran near residential areas, raising concerns about the release of toxic vapors, odors, and potential violations of air quality regulations. The customer required a safe, rapid, and fully compliant pipeline degassing solution that would prevent any benzene vapor release and ensure community safety.

Solution

Envent Corporation provided a custom-engineered solution using our advanced industrial degassing equipment:

  • A vapor-liquid separation vessel was deployed to collect and manage up to 100 BBL of liquid hydrocarbons, ensuring effective pre-treatment before vapor destruction

  • Vapors were routed to our EMTOS (Envent Mobile Thermal Oxidizer System), designed to exceed EPA BACT standards and specifically optimized for H₂S vapor control

  • High-pressure flange hoses and fittings were used throughout the system to ensure vapor-tight integrity and prevent leaks during pipeline depressurization

  • The process safely evacuated approximately 60,000 SCF of vapor from 100 PSIG to 0 PSIG in under one hour

  • The separation vessel received fewer than 10 BBL of liquid, minimizing hazardous waste handling

Benefit

Envent’s pipeline vapor control solution delivered significant time and cost savings for the customer. The use of nitrogen purging and mobile thermal oxidation enabled the safe and rapid depressurization of the pipeline, completing the degassing operation in less than an hour—a fraction of the time required by conventional methods.

This solution also prevented a reportable benzene release under EPA emission standards (>10 lbs/day), ensuring full regulatory compliance. Envent’s expertise in H₂S vapor mitigation, pipeline evacuation services, and zero emission pipeline solutions helped the customer meet environmental and safety objectives efficiently and without incident.

Mid-West, USCG Certified Marine Vapor Recovery System

Portfolio Categories: Case Studies, Marine Vapor Recovery, Turnaround Services, Vapor Control, and Vapor Scrubbing.

Challenge

A Mid-West refinery needed to take a refined product pipeline out of service for planned internal maintenance. However, they required a solution that would allow continued refined product shipments to market without disrupting production or creating regulatory compliance risks.

Because vapor emissions and odor control were significant concerns, the solution needed to comply with USCG (United States Coast Guard) marine vapor recovery regulations. Additionally, maintaining vapor emission compliance was essential to avoid fines or operational restrictions. The refinery also wanted to explore options that would allow barge loading flexibility, improving operational efficiency and market access.

Solution

Envent Corporation proposed a temporary, portable Marine Vapor Control System (MVCS) fully pre-certified by the USCG. Envent’s system enabled the refinery to load refined product into barges from the North Dock. Barges then transported the product downstream to the South Dock for offloading—eliminating the risks associated with operating the pipeline during maintenance.

Envent’s Marine Vapor Control System included:

  • A Dock Safety Unit (DSU) equipped with vapor scrubbers for safe vapor handling

  • An Envent Mobile Emission Control System (EMECS) designed to meet or exceed EPA BACT and USCG 33 CFR 154 Subpart E requirements

  • Rapid deployment and operational testing, allowing the system to be fully functional within days

  • Complete removal post-project with zero impact to facility infrastructure

Benefit

Envent’s engineered vapor control solution allowed the refinery to:

  • Maintain full regulatory compliance with vapor emissions limits

  • Avoid costly operational delays by continuing to load and ship product without interruption

  • Eliminate risks associated with the pipeline option

  • Reduce overall project costs and minimize resource strain

The success of this project enabled the refinery to retain a 5-year certified Envent DSU and MVCS for future emergency loading operations. The refinery avoided an estimated $3 million in lost opportunity costs through Envent’s expertise in marine vapor recovery systems, turnkey vapor control, and emission compliance strategies.

Midwest Refinery Turnaround Services

Portfolio Categories: All, Case Studies, Degassing, Mobile Water Treatment, Odor Control, Turnaround Services, and Vapor Control.

Challenge

A Midwest refinery contracted Envent to provide degassing and vapor control services.  The refinery planned a major turnaround and had multiple critical-path process units that needed industrial degassing and industrial vapor control services for safe entry into process vessels.  EPAs mandates and RSR vapor control regulations on flareless turnarounds required eliminating flaring activity and capacity of recovery units, an alternative was needed to remove bottlenecks and minimize delays.

Solution

Envent Turnaround Degassing Services Group engineered solution that included H2S Scrubbers and thermal oxidizers for industrial degassing of vessels and pipe systems.  Envent’s engineers worked with the refinery Operations, Turnaround Coordinators, and Environmental group to provide a safe process for vapor freeing using Envent’s mobile degassing systems.

The Envent solution included H2S Scrubbers – 2 x ASME-rated circulating scrubbers.  The hot-wash system would receive steam and non-condensable material from the low-pressure system through heat exchangers, knock out vessels, ASME H2S Vapor Scrubbers which would vent to Envent’s Mobile Emission Control Systems (EMECS 70s) the largest mobile vapor control systems.  Water collected will be processed through an Envent Mobile Wastewater Treatment System.

Benefits

The results from using this system expedited the decontamination period, prior to a turnaround, from 3 weeks to 7 days.

 

Safety is our #1 priority.

Southern California Refinery Excess Fuel Gas Elimination Project

Portfolio Categories: All, Case Studies, Degassing, GHG Emission Control, and Vapor Control.

Challenge

A Southern California refinery needed to shut down its Hydrogen Plant to perform critical maintenance outside of its normal turnaround cycle. This unit utilized a majority of the refinery’s produced fuel gas, and maintaining operations at the remainder of the facility required a solution for handling approximately 3 million standard cubic feet per day (SCFD) of excess gas.

Routing this volume directly to the flare system would have constituted a major flaring event—triggering regulatory scrutiny and exceeding permit allowances. The refinery required a Flare Minimization Plan and contracted Envent Corporation to provide a compliant, engineered solution to eliminate unnecessary flaring during this high-risk project.

Solution

Envent Corporation designed and executed a custom vapor control solution, complete with all necessary environmental permitting to meet the refinery’s flare minimization goals. Key components of the solution included:

  • Upfront engineering design, incorporating detailed vapor management system schematics and a formal Process Hazard Analysis (PHA)

  • A high-pressure knockout vessel to capture and separate liquids from the vapor stream

  • Deployment of three EMECS (Envent Mobile Emission Control Systems) to safely process the excess fuel gas through thermal oxidation, achieving >99.9% Destruction Removal Efficiency (DRE)

  • Onsite project engineers and field supervisors providing continuous oversight to ensure noise minimization and uphold the refinery’s good neighbor commitments

This solution allowed the refinery to maintain operations without exceeding permitted emissions or resorting to flaring.

Benefit

Envent’s engineered vapor control solution allowed the refinery to:

  • Avoid a major flaring event during the Hydrogen Plant shutdown

  • Maintain full compliance with environmental regulations and air district permit limits

  • Complete critical maintenance with minimal operational disruption to other refinery units

  • Streamline internal processes, as the refinery only needed to oversee the Management of Change (MOC) and provide tie-in points

This project highlights Envent’s expertise in flare minimization strategies, turnaround vapor control, and refinery emissions management—delivering solutions that reduce risk, protect air quality, and maintain operational flexibility.

Quote from Project Manager

“I wanted to thank you guys for the great work in execution of this project. It was definitely a success, and everyone was happy with the outcome. NO FLARING!”

In June 2017, Envent Corporation achieved 1 million man-hours without an OSHA recordable injury. We maintain a TRIR of 0.0 for 6 years. We believe Safety is No Accident.

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