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 had a need to load gasoline, ethanol, and other high vapor pressure materials (classified as MVR products) onto barges. MVR products are required to have vapor control on them during transfer onto the vessel. The loading terminal is not equipped with any form of vapor recovery device on the dock. Without the ability to load product, the refinery and terminal will miss out on potential profits for the sale of the MVR products. A temporary solution is needed to control vapors during loading events while maintaining compliance with strict US Coast Guard regulations (33 CFR 154 Subpart P).

 

Solution

Envent implemented a vapor control system designed specifically for compliance with USCG regulations. The industry leading EMECS thermal oxidizer was utilized along with Envent’s Dock Safety Unit (EDSU). Envent engineers worked with various crafts to facilitate the installation and testing of the equipment per USCG regulations. These regulations limited distances from the dock, pipeline size, PRV/VRV requirements, and many more. Lastly, Envent received a certification letter from an approved third party USCG representative confirming compliance with 33 CFR 154 Subpart P. A copy of this letter is filed in the office of the terminal manager.

 

Benefit

The refinery terminal was able to load MVR products onto ships and barges at a flow rate of 7500 BBL/hr. The terminal vastly increased their profit margins by having a faster, better, and more cost effective route for moving product. Choosing Envent proved to be a great choice for the refinery, as it will make the terminal company millions over the next few years.

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 was preparing for an internal pipeline maintenance project and was exploring options for how to take the vent and a refined product pipeline out of service to sustain refinery production and continue to ship refined project to market. Vapors emissions had to be controlled by a USCG Certified Marine Vapor Recovery System. Vapors and order issues were a major concern. Being in compliance with vapor emission limits was necessary. The refinery may be able to sell product from their dock, greatly increasing flexibility and cost effectiveness to potential customers.                                 

Solution

Envent proposed a temporary, portable United States Coast Guard approved Marine Vapor Control System (MVCS) to load the product into barges at the North side of the refinery. The barges would then float down river and offload at the South side of the refinery. This eliminated nearly all of the risks associated with the pipeline option. Envent’s MVCS is all pre-certified by the US Coast Guard, setup and operational testing occurred within a few days’ time. Upon project completion, the MVCS was quickly removed without a trace. The Envent system consisted of a Dock Safety Unit (DSU) with a vapor scrubber and Envent Emission Control Systems (EMECS). 

Benefit

Not only did Envent’s MVCS control vapor emissions to achieve compliance and eliminate the risks associated with the pipeline option, it reduced refinery cost and minimized resources. The refinery now has a 5 year certified Envent Dock Safety Unit (DSU) and MVCS they call back on site for any emergency loading. The refinery was able to continue to load and ship product to market without interruption. The net result was estimated at $3 Million in lost opportunity costs if Envent was not able to engineer a system that would allow the refinery to load ships.

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 bring down their Hydrogen Plant to perform critical maintenance outside of the normal turnaround cycle. To bring down the unit that utilizes most of the produced fuel gas of the refinery while maintaining operations in the rest the plant, approximately 3 million standard cubic feet per day of gas needed to be processed. Such a release to the flare system would have been an extraordinary event. The refinery needed a Flare Minimization Plan. Envent Corporation was contracted to provide the solution and execute.

Solution

Envent Corporation went to work to provide an engineered solution, complete with the necessary environmental permits for the Refinery Flare Minimization effort. We provided upfront engineering necessary to complete a design of the vapor management systems, culminating with the Process Hazards Analysis (PHA). Envent was able to handle an excess 3 million scf per day to avoid Flaring events. Envent provided a High Pressure Knock Out Vessel followed by 3 EMECS units. Envent’s solution did not stop there, our project engineers maintained strong oversight, minimizing noise and maintaining the refinery’s good neighbor priorities.

Benefits

Envent delivered an efficient solution to support the refinery’s Hydrogen Plant Shutdown only had to oversee the Management of Change (MOC) process and provide our tie-in points. The project was a huge success and the customer was very pleased. Flaring excess gas was avoided during this effort.

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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