Hydrotreater Turnaround Vapor Control

Hydrotreater Turnaround Vapor Control

Portfolio Categories: Case Studies, GHG Emission Control, Turnaround Services, Vapor Control, and Vapor Scrubbing.

Challenge

The customer needed to clear their hydrotreater of volatile vapors and product in order to allow manned entry for maintenance activities. During this process, there would be limited availability to use the flare or FGRU to purge vapors from the unit. Additionally, there were high concentrations of hydrogen gas and H2S that needed to be managed to make entry safe. Ultimately, the customer needed a supplemental system that could receive, scrub, and process excess unit vapors to maintain their project timeline.

Solution

Envent provided (2) EMECS thermal oxidizer units to combust process vapors at a 99.9% destruction rate efficiency. Additionally, Envent’s system included (4) ESCRUB recirculating scrubbers that neutralized H2S in the streams, (2) heat exchangers to cool and condense vapors, and a collection system to move condensates back to a designated containment. Lastly, additional safety measures were implemented on the thermal oxidizer to allow for safe combustion of up to 100% hydrogen streams.

Benefit

Envent’s system aided the customer by providing an additional avenue to process unit vapors, thereby allowing the customer to purge their system more quickly. The recirculating scrubbers were able to neutralize all H2S vapors in the vapor stream, eliminating any chance of hazardous SOx emissions from being formed. Additionally, the high thermal capacity of each EMECS allowed Envent to process heavily hydrocarbon-ladened vapors without compromising on flow rates. Nitrogen purge capacity was also increased due to Envent’s presence by providing the customer’s FGRU with additional capacity to manage an inert stream. Overall, the system provided by Envent reduced the customer expected turnaround timeline by ~2 days, thereby saving the end user several million dollars!

Envent’s solution to landfills logistical and regulatory challenges

Portfolio Categories: Case Studies, GHG Emission Control, Odor Control, Soil Vapor Extraction and Remediation Systems, and Vapor Control.

Challenge

A landfill facility undergoing expansion required supplemental soil vapor extraction (SVE) and vapor control services to support its existing vapor recovery system. As new SVE wells were installed along the periphery of the plant, the site’s legacy blowers could no longer maintain the required vacuum levels, and the existing flares lacked sufficient thermal capacity to destroy the high volumes of methane gas being extracted.

The customer needed a custom-engineered vapor control solution capable of:

  • Maintaining a vacuum of 50 inches of water column (INWC) on the SVE header

  • Processing high-moisture, high-solids, and highly combustible landfill gas

  • Achieving full regulatory compliance for methane and VOC emissions

This project presented unique challenges associated with landfill gas control technologies, including the need for moisture separation, solids filtration, and a safely managed inert vapor stream.

Solution

Envent Corporation designed and deployed a turnkey system for landfill vapor mitigation and soil vapor extraction, leveraging both proprietary equipment and industry-best engineering:

  • A specialized SVE blower system, capable of 60 INWC and 2,500 CFM, equipped with spark-resistant housing, explosion-proof electrical components, and continuous-duty construction

  • The deployment of an EMECS 70—a direct-fired mobile thermal oxidizer with a 70 MMBTU/hr thermal capacity—ideal for handling pressurized, inert, and high-BTU vapor streams without the addition of dilution air

  • Inline liquid knockout pots, solid separation filters, and an automated liquid drain system enabled continuous operation without shutdowns due to condensate accumulation

  • Full 24/7 on-site operation by Envent technicians, with real-time compliance monitoring, safety logging, and support to ensure adherence to local, state, and federal air quality regulations

Benefit

Envent’s engineered solution allowed the landfill to maintain environmental compliance, avoid costly violations, and continue full-capacity operations during a critical site expansion. By combining soil vapor extraction, methane vapor control, and thermal oxidation in a fully integrated system, Envent eliminated the plant’s risk of uncontrolled emissions and created a safer working environment for both personnel and the surrounding community.

This project demonstrates Envent’s leadership in landfill vapor control, emission control services, and mobile thermal oxidizer deployment—delivering scalable, regulatory-compliant results in even the most complex vapor management scenarios.

Mobile Multi/Dual Phase Extraction Pilot Test

Portfolio Categories: All, Case Studies, GHG Emission Control, Soil Vapor Extraction and Remediation Systems, and Vapor Control.

Challenge

There was a large plume of MTBE below grade near a waterway strait. Envent had been collecting ground water and treating it from this site for approximately 10 years but due to multiple years of drought ground water was no longer mobilizing large concentrations of MTBE for removal.

Solution

Envent was asked to provide a multi-phase or dual phase extraction system to target the heart of the plum since we were already onsite providing groundwater treatment services. We brought is a full vacuum DVT blower with a 300 gallons KO pot, automatic pump on level control, and a thermal oxidizer for destruction of the vapor phase MTBE/GRO gases.

Benefit

We were able to target the heart of the plum with soil vapor extraction, while still managing the water that came from the extraction wells. It was a great way to keep the clean up/remediation efforts moving forward when the amount of groundwater slowed down due to draught.

Duct Removal NOx Vapor Control – Richmond, CA

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

Challenge

A customer needed to remove 50 feet of 60-inch ducting containing hazardous nitrogen oxide (NOx) vapors. The facility, located next to a major highway and bridge in the California Bay Area, posed a high-risk scenario due to its proximity to a heavily populated area. Without proper vapor control, the NOx could have created a toxic orange cloud, violating air quality regulations and endangering public health. The customer relied on Envent Corporation, a leader in industrial degassing and vapor mitigation, to ensure safe and compliant removal.

Solution

Envent deployed a mobile vapor control system using a 2,000 CFM blower connected to an 8″ flange provided by the facility. To manage emissions throughout the project, multiple 8″ connections were utilized.

To scrub the NOx vapors effectively, Envent provided three ESCRUB 6000 recirculating vapor scrubbers, a trusted system in our mobile scrubbing services fleet:

  • Scrubber 1 was filled with a sulfamic acid solution for primary NOx neutralization

  • Scrubber 2 was filled with a caustic solution for secondary treatment

  • Scrubber 3 was placed on standby as a redundant unit, enhancing safety and operational reliability

In addition, Envent extended vapor scrubbing to a hooch, where cut ducting sections were stored, cleaned, and prepared for disposal. Vapors from this enclosure were also treated using chemical scrubbers connected via a customer-supplied fitting.

Benefit

By leveraging Envent’s engineered vapor control solutions, the facility remained in full compliance with Bay Area Air Quality Management District (BAAQMD) regulations. The operation eliminated the risk of a visible toxic cloud and prevented NOx emissions from impacting the surrounding community. This project highlights Envent Corporation’s ability to deliver customized, mobile vapor control services that ensure regulatory compliance, protect public health, and support complex industrial maintenance efforts in high-risk areas.

 

 

Gulf Coast Refinery Changing Focus

Portfolio Categories: Case Studies, GHG Emission Control, Marine Vapor Recovery, and Vapor Control.

Challenge

A gulf coast refinery was recently the target of a large hurricane: a storm that caused them significant damages. It was at this point, the refinery decided to change their model from a refinery into a storage terminal facility. During this process, the facility found value in selling their current product via marine vessels. When loading vessels with certain hydrocarbon products, the US Coast Guard mandates the use of a Dock Safety Unit (DSU) or MVR (Marine Vapor Recovery) system as an added safety feature to prevent the possibility of a flame. Unfortunately, however, the facility’s MVR had been destroyed in the storm.

Solution

The facility reached out to Envent with their problem, and Envent responded with a BACT (Best Available Control Technology) solution. Envent maintains and operates their own MVR; the EDSU. The Envent Dock Safety Unit (EDSU) is a portable equivalent to many facilities’ permanent MVR installations. This, paired with Envent’s EMECS style thermal oxidizer, saved the facility from having no means to transport this product from their facility via marine vessels.

Benefit

The facility benefited from utilizing Envent’s mobile equipment at time they needed it most. The facility was able to quickly move product without spending a significant amount of resources (time and money) repairing the fixed MVR system on site. Envent earned a deserved trust with this facility, and this opportunity has led to future growth between Envent and this company, which is one of the country’s largest refining companies.

 

 

Liquid Natural Gas (LNG) Bunkering

Portfolio Categories: Case Studies, GHG Emission Control, Marine Vapor Recovery, and Vapor Control.

Challenge

A customer of ours has two cargo ships that constantly transfer cargo up and down the west coast. These ships are always sailing back or forth with commerce and are on extremely tight schedules. Envent Corporation was challenged with assisting in the commissioning a new LNG fuel system on one of these cargo ships, while minimizing downtime. LNG Bunkering requires cooling in steps with nitrogen to cryogenic temperatures of ≤-156 °C or ≤-250°F in order to prepare the fuel system materials to receive liquid natural gas (LNG) at -260°F. Once the fuel system is cooled, liquid natural gas is introduced, but the system cannot be utilized until all N2 has been removed.

Solution

The customer will set up a liquid nitrogen pumper to cool the fuel system in prep for LNG. Envent Corporation will set up ambient air vaporizers and an EMECS 70 thermal oxidizer to receive N2 and natural gas from the commissioning process, until all N2 has been removed. The cryogenic gases will be transported through ss braided hose from the ships fuel system to our ambient air vaporizers, bringing the gas temperature up above minimum allowable working temperatures. The gas mix will then continue to be safely oxidized by our EMECS 70.

Benefit

Envent Corporation’s engineering, equipment selection, and expertise allows us to take this dangerous cryogenic/explosive fuel from the bunkering process and quickly/safely combust it in a controlled burn. Thus allowing, our customer to safely convert their cargo ship into a clean burning fuel vessel without emitting large volumes of greenhouse gases in the process.

 

 

Envent Vapor Control Assisting with COVID 19 Vaccine

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

Challenge

In response to the COVID-19 pandemic, the Biomedical Advanced Research and Development Authority (BARDA) and its Contract Development and Manufacturing Organization (CDMO) network were rapidly established to scale vaccine production.

One of Envent’s customers was approved to join the network to manufacture COVID-19 vaccines and needed to begin production quickly. The client required an automated vapor control system to safely manage VOC emissions and process vapors from pharmaceutical manufacturing units—while ensuring compliance with strict environmental and safety regulations.

Solution

Envent Corporation provided a custom-engineered vapor control solution by modifying one of its mobile thermal oxidizer systems to support automation and real-time monitoring. Key enhancements included:

  • Automated inlet valve regulation based on process vapor flow

  • Integrated temperature monitoring and recording for compliance and safety documentation

  • Alarm and communication upgrades: a cell phone alert system and control room integration for immediate shutdown notifications

  • On-site support by Envent’s engineers and safety supervisors for system setup, safety meetings, and operator training

This tailored solution combined Envent’s emission control expertise with pharmaceutical-grade operational reliability.

Benefit

Envent’s vapor control system enabled the client to safely begin COVID-19 vaccine production in under 10 days, meeting urgent national health needs. The automated solution eliminated the need for constant manual oversight, saving the customer hundreds of thousands of dollars in labor costs.

This project showcased Envent’s strength in engineered vapor control solutions, thermal oxidizer automation, and rapid mobilization. Whether for chemical manufacturing, refinery vapor control, or emergency response, Envent continues to lead with innovation, safety, and compliance-driven performance.

Envent provides a customized Noise Emission Control System

Portfolio Categories: All, GHG Emission Control, and Vapor Control.

Challenge

A customer in the Midwest needed to reduce noise coming from a natural gas pipeline blowdown. Pipeline blowdown operations can be very loud have the potential to disrupt the immediate area. The gaseous contents of the pipeline are at high pressure and when that pressure is under controlled release, creates an unpleasant rushing sound. ENVENT was called upon to assist with the noise emissions.

Solution

ENVENT engineers developed a portable pipeline silencer and constructed it in-house. This silencer was designed to lower noise emissions while allowing for a quick de-pressure of the pipeline. We also used our pipeline liquid/gas separator upstream of the silencer to capture any condensate or residual product in the pipeline during de-pressure and subsequent pigging.

Benefit

The customer was very pleased with the performance of the silencer, allowing for a faster blowdown with no complaints from the adjacent neighborhood. Moreover, the pipeline liquid/gas separator ensured there was no risk of any liquids touching the ground. ENVENT provided a noise emissions control system that doubled as a spill prevention system.

 

Emergency Response, Hydrogen Sulfide (H2S) Vapor Control Project

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

Challenge
A petroleum refinery scheduled a turnaround that required taking several gasoline vessels and process units out of service. As part of the refinery turnaround services, the first step was to identify the vapor point on where we would perform the vessel degassing—depressurizing and decontaminating the units of Volatile Organic Compounds (VOCs) and Hydrogen Sulfide (H₂S).
Solution
Envent was contracted to supply two temporary vapor degassing and Hydrogen Sulfide (H₂S) vapor control systems to safely and efficiently combust VOCs from the process units. As part of its refinery turnaround services, Envent provided two high-pressure regulators to manage high inlet pressures and reduce them to a controlled level. Additionally, two recirculating caustic scrubbers were deployed to neutralize Hydrogen Sulfide (H₂S) before the vapors were combusted by Envent Mobile Emission Control Units (EMECs). Envent delivers the most advanced degassing technology available for gas scrubbing and tank and vessel degassing applications.
Benefit
Envent delivered a safe, efficient, and compliant solution for vessel degassing and vapor control during the refinery turnaround. The high-pressure regulators ensured a controlled pressure reduction for safe operation. Recirculating caustic scrubbers effectively neutralized Hydrogen Sulfide (H₂S), minimizing environmental and health impacts. The thermal oxidizers in the Envent Mobile Emission Control Units (EMECs) efficiently combusted vapors, achieving regulatory compliance and reducing emissions. The integrated vapor control system—combining H₂S scrubbing with Envent Mobile Emission Control Units (EMECs)—streamlined the turnaround process and enabled VOC controls, maintenance and modifications to proceed on schedule, achieving vapor-free status and environmental compliance ahead of plan.

Envent Finds Themselves Inside Another Houston Refinery

Portfolio Categories: Turnaround Services, Vapor Control, and Vapor Scrubbing.

Challenge

A major Houston refinery engaged Envent Corporation in a competitive bidding process alongside several thermal oxidizer companies to support the cleaning and degassing of an underground API separator. This rectangular tank with an external-floating roof had accumulated years of wastewater hydrocarbons from multiple refinery operations—resulting in a potentially hazardous, unidentified mix of vapors and an estimated 5–6 feet of sludge.

Due to the high vapor pressure of residual hydrocarbons and the potential presence of benzene, H₂S, and other volatile organic compounds (VOCs), the project required an experienced team capable of delivering compliant, high-performance vapor control services.

Solution

The refinery employed frac tanks, pumps, a centrifuge, and a manway cannon to conduct the physical cleaning process. Envent Corporation supported the operation with comprehensive, mobile vapor control throughout every stage.

Key highlights of Envent’s solution:

  • Vapors displaced during frac tank filling were routed to Envent’s EMTOS (Envent Mobile Thermal Oxidizer System)—engineered to exceed EPA BACT guidelines with >99.9% destruction efficiency (DRE)

  • EMTOS units operated at temperatures exceeding 1400 °F, providing full combustion of VOCs and ensuring regulatory compliance

  • Once the API tank was physically cleaned, Envent utilized the mobile thermal oxidizer fleet to complete the final degassing stage

Envent’s system configuration prevented emissions, controlled tank vapor management, and protected both workers and the surrounding community from toxic exposures.

Benefit

Thanks to Envent’s mobile degassing and thermal oxidizer technology, the refinery successfully completed the project safely, efficiently, and 100% in compliance with environmental regulations.

This marked Envent’s first major project at the facility, and the flawless execution built a solid foundation for future collaboration. The refinery team commended Envent for its clear communication, engineering support, and reliable vapor control solutions—leaving a lasting impression and demonstrating why Envent is the trusted name in refinery vapor control and tank degassing for refineries.

Downtown Soil Vapor Extraction

Portfolio Categories: Soil Vapor Extraction and Remediation Systems, Vapor Control, and Vapor Scrubbing.

Challenge

Extremely high levels of Methane and over 10,000ppm of H2S in the soil under downtown Los Angeles near the La Brea Tarpits was making the path for a large tunnel boring machine very difficult. To get through the worst sections they knew they were going to need a solution to keep the levels in a safe range to keep the crew and equipment underground safe and avoid costly evacuations and subsequent delays due to hazardous gasses.

Solution

Envent provided equipment over a three-year span ranging from small carbon vessels all the way up to our 42 MMBTU/H EMECS42 Thermal Oxidizer along with three other Smaller thermal oxidizers. All of these are working in parallel with recirculating scrubbers to process the high levels of H2S and destroy the methane.

Benefit

Alternative solutions were estimated to be 4-5 times as costly and had major safety concerns. The Envent solution left almost no long term underground infrastructure and required very little disturbance aboveground besides the traffic control for the work area.

 

Pipeline Hydro Test – Water Treatment – West Coast

Portfolio Categories: Mobile Water Treatment.

Challenge

Envent Corporation was called upon to treat approximately 619,758 gallons of hydro-test water from two newly constructed pipelines on the west coast.  The newly constructed pipelines required hydro-static testing after they were installed to ensure there are no leaks and the pipelines are ready for full scale operation.  The challenge was what to do with all of the water once it has been used for the hydrostatic test?  Off hauling the water in tanker trucks to a treatment facility would be extremely cost prohibitive due to the remote location of the pipeline.

Solution

The solution was to have Envent acquire discharge permits, safely treat the water and discharge it on site.  After the pipeline testing was complete, a pig was ran through the line displacing the water into multiple temporary storage tanks while Envent simultaneously treated/discharged the hydro test water at ~400GPM to safe discharge specifications. The system included chemical injection, pH control, granular activated carbon, pumps, and filters. Envent obtained local discharge permits, created a treatment scheme based off the analytical, provided equipment and the manpower  to operate the onsite treatment system.

Benefit

The client was able to perform the necessary hydro-static testing of both lines with no delay to the project because Envent’s treatment system was designed to treat the water as fast it could be removed from the pipeline.  The water was safely, environmentally and economically treated then discharged to permit conditions. Additionally, the surrounding rural area was not subject to heavy hauling traffic and the treated water was returned to the environment where it came from, meaning no environmental impact.

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