Degassing Of An LNG-Powered Freight Vessel

Degassing Of An LNG-Powered Freight Vessel

Portfolio Categories: Case Studies and Marine Vapor Recovery.

 

Challenge

A customer tasked Envent to create a temporary system allowing for the degassing of an LNG-powered freight vessel while it was docked at port in order to perform critical maintenance on the vessel. The solution would allow the customer to continue standard operations without delay, remove Natural Gas Vapors from within the fuel tanks, and maintain compliance with Environmental Protection Agency (EPA) clean air standards as well as the US Coast Guard. Envent has USCG certifications to operate on the marine water ways and docks.

Solution

Envent supplied the customer with an EMECS 70, the industry leading mobile thermal oxidizer unit. The freighter has two 900 m3 LNG tanks each containing trace amounts of liquid LNG and pressurized vapors. Vapors are vacuumed out of the vessel using state of the art blower units and then routed to the thermal oxidizer at a control pressure and incinerated to greater than 99.9% efficiency at a rate of 60,000 CFH. This process continued until both LNG vessels were completely de-pressured. The vapor control, vessel degassing and purging of the vessels is completed within hours. Mobilization and demobilization of the marine vapor control systems is seamless.

Benefit

Envent’s solution allowed for the customer to successfully continue operations without having to delay any standard procedures. In addition, the customer was able to start maintenance work on both LNG tanks immediately after this process was completed. Both of these achievements allowed the customer to save a valuable amount of time and money.

Pipeline Evacuation Project

Portfolio Categories: All, Case Studies, and Compression.

Challenge

A West Coast natural gas transmission and distribution company required inspection & maintenance on a segment of methane pipeline. That section of pipe would need to be drepressured/ evacuated and deinventoried prior to performing the required maintenance. The client did not want to release the natural gas into the atmosphere (~1 Million lbs CO2e), or lose that volume of valuable natural gas to a flaring.  Besides the May 2023 promulgation of Part Two of the Pipeline and Hazardous Materials Safety Administration (PHMSA) MEGA Rule requires measures to enhance pipeline safety and reduce pipeline failures. PHMSA issued the Mega Rule in response to a number of incidents that highlighted the need for improved pipeline regulations. .  The customer opted for the EPA Best Management practice of Pipeline recompression.  Envent was contracted to perform this with our state-of-the-art line of mobile cross-compression pipeline evacuation units.  Operators of natural gas pipeline systems routinely reduce line pressure and discharge (“blowdown”) gas from pipeline sections to ensure safe working conditions during maintenance, testing, repair, and replacement activities.  This impacts the 3 million miles of natural gas pipelines that crisscross the US.

Solution

These portable recompression units require no additional utilities. The natural gas powered 400 Hp engine, drives the portable cooler, compressor, and alternator for battery backups. Equipped with industry standard Safety Shut Off Valve, bolt up consists of a single hose run to and from the compressor. No regulator, no additional fuel line, or no added tie in points. Suction gas pressure is introduced into the compressor, which is compressed high enough to move the volume back into the main pipeline. As suction pressure drops, the unit auto adjusts its compression ratio to meet its target discharge pressure. Envent’s fleet is comprised of 1, 2, and 3 stage compressors capable of evacuating pipelines to <5 psi, from 1400 psi! A summary report is delivered to the client with swept volume, $ saved, CO2e documentation, and much more. We provided our newest unit for this temporary compression project.

Benefit

By using Envent, the client can have the peace of mind knowing that they will have the latest in pipeline evacuation technology. Equipped with Ariel Smart Compressor technology, these units provide a state of the art advancement in temporary pipeline recompression, also known as pipeline evacuation and cross-compression: Remote monitoring, data logging, automated PSV protection (automated recycle loop), and much more. Since 1992, reliability, efficiency, and responsiveness are core values within this business segment and to Envent. In addition to the benefits listed above, the client also benefits financially, as they are able to recover the cost of the gas recovered.

Envent is ready to respond to your next pipeline evacuation needs! We help our customers throughout the US and Canada with methane mitigation and industrial decarbonization.

Compressor Station Pulldown

Portfolio Categories: Compression.

 

Challenge

Envent’s North-East Natural Gas Transmission customer required maintenance of a 52 inch pipeline due to a leak. The problem had to be resolved immediately. The problem could have resulted in adverse environmental impacts and financial loss if it was not addressed immediately

Solution

Envent responded within 24 hours to the jobsite with our newest 3 stage compressor allowing us to draw pressure down to 15 psig within 14 hours. The Envent Cross Compression Unit compressed the natural gas from the impacted natural gas transmission line to another section of natural gas pipeline with zero emissions.

Benefit

Envent played a pivotal role in safeguarding our customer from the potential loss of natural gas resources and yielding environmental benefits of zero emissions. This accomplishment is a testament to Envent’s capability, as we successfully execute the task but also accomplished it well within the client’s timeline. Envent provides established offices throughout North America allow us to immediately mobilize to jobsites in the US and Canada within hours. Our Natural Gas Cross Compression Units are the largest and most efficient units on the market.

Butane Tank Degas

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

Challenge

A client required the stripping and cleaning of a butane storage vessel as part of a facility transition to renewable diesel service. Envent was assigned the responsibility of degassing the tank and delivering continuous vapor control to minimize tank atmosphere to non-explosive levels. Furthermore, the tank needed to be inerted to prevent oxygen ingress into the vapor space, and the sub-freezing ambient temperature conditions had to be taken into account while devising a solution.

 

Solution

Envent supplied two CSA-compliant EMECS 70 thermal oxidizers to offer redundant vapor control for the butane tank. Each oxidizer unit was modified in accordance with Canadian Standards, enabling their operation under local permitting. Both units were integrated into an existing flare line system, allowing tank vapors to be channeled to each combustor. In addition, Envent provided a nitrogen generation system to introduce inert makeup gas into the tank atmosphere. Each generator was capable of heating the nitrogen prior to injection, preventing the formation of condensable materials in the vapor lines. As a result, Envent continuously swept VOC-laden vapors to the thermal oxidizers for 99.9% DRE combustion, while oxygen-free inert gas was introduced into the tank volume.

 

Benefit

The thermal oxidizer system, furnished by Envent, enabled the client to successfully degas the butane tank to levels appropriate for manned entry and maintenance. Envent delivered a turnkey system that complied with all local regulations, resulting in a seamless entry and setup process. The end user was also able to minimize their emissions and adhere to their maintenance schedule.

Refinery Wastewater Treatment – Innovative Benzene Removal Solution


Challenge

A renowned US refinery faced a critical challenge regarding the removal of Benzene from wastewater. The wastewater contained several other constituents of lesser concern, posing a significant environmental and operational hurdle for the refinery.

Solution

Envent rose to the challenge and devised an ingenious solution to address the Benzene removal issue. The team designed, constructed, implemented, and operated a cutting-edge Nitrogen stripping tower system. This specialized system efficiently eliminated 93% of Benzene from the wastewater while allowing the other constituents to pass through unaffected. By integrating this solution, Envent ensured a seamless flow of Benzene-stripped wastewater back into the refinery system, continuing its journey towards the wastewater treatment plant. Moreover, the Nitrogen-stripped Benzene vapors were skillfully directed to a state-of-the-art Thermal Oxidizer, where they were destroyed with an impressive efficiency of 99.9%.

Benefit

The implemented system showcased remarkable advantages, revolutionizing the refinery’s wastewater treatment process. Notably, the system operated flawlessly, eliminating the need to open the towers for media replacement, debris clearing, or any internal servicing. This feature significantly enhanced the system’s reliability and minimized downtime, resulting in improved overall operational efficiency. Furthermore, the solution enabled the customer to conduct extensive parameter testing, fine-tuning the system for optimal performance. As a direct consequence, the  refinery successfully achieved a substantial reduction in Benzene emissions throughout its operations. This notable environmental benefit underscored Envent’s commitment to sustainability and responsible waste management practices.

By implementing this innovative wastewater treatment solution, Envent not only addressed the refinery’s immediate challenge of removing Benzene effectively but also showcased our expertise in designing and deploying advanced environmental technologies. Envent’s success in this project solidified our position as a trusted industry leader in providing tailored and sustainable solutions for complex environmental problems.

Flare Gas Scrubber System & Compliance

Portfolio Categories: Case Studies and Vapor Scrubbing.

Challenge

An Envent customer needed to perform maintenance on their distillation unit, SATS unit, and flare. For this project, the customer rented a temporary flare to combust VOCs while their main flare unit was serviced. The customer came to Envent requesting sour gas scrubbing. H2S levels up to 15,000 ppm were to be expected in their flare gas. Customer also requested that the H2S concentration be neutralized to remain in compliance with the EPA. In order to stay in compliance, H2S concentrations could not exceed 160 ppm at their temporary flare.

Solution

Envent proposed a customized scrubber system to neutralize the sour gas so that the customer could be in compliance with the EPA. Envent mobilized multiple pieces of equipment including three ESCRUB-2000s, three high pressure knockout pots, and two frac tanks. The three scrubbers and knockout pots were connected directly to the customer’s flare header in parallel in order to handle the highest flows and concentrations that were provided. The scrubber system was manned 24/7 by a team of two technicians and one crew lead to ensure operation and caustic change-outs were performed safely and efficiently.

Benefit

Envent provided an efficient setup which neutralized the H2S concentrations in the customer’s sour gas. The scrubber system was manned 24/7 to ensure equipment was fully functional and to keep the customer in compliance. Envent’s customer was satisfied with the professionalism and safe work practices when handling hazardous chemicals.

Hydrotreater Turnaround Vapor Control


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


Challenge

The challenge of this project is to provide supplemental soil vapor extraction (SVE) and vapor control to the plants existing vapor recovery system. Additional soil vapor extraction wells were installed on the periphery of the plant due to the expansion of the landfill. The plants SVE blowers are unable to provide sufficient vacuum and the flares lacked the thermal capacity to maintain regulatory compliance. Envent was tasked with designing and implementing a system that could maintain a vacuum of 50 inches of water column on the new SVE header and provide vapor destruction of the extracted Methane gas. SVE and processing of landfill gas has inherent problems; the extracted vapor is entrained with moisture, solids and is highly combustible. An Engineered solution is necessary to separate the moisture and solids while maintaining an inert process stream to allow safe processing.

Solution

Envent Engineered the following system to solve these challenges. The system includes a SVE blower capable of maintaining a vacuum of 60 INWC and a 2500 CFM flow rate. The blower is equipped with a spark resistant housing and fan blade with an explosion proof electrical panel. An EMECS 70 was selected as the vapor destruction unit due to its large thermal capacity of 70 MMBTU/HR, as well as its advanced safety features. The EMECS 70 is a direct fired thermal oxidizer with no addition of dilution air which is well suited for the pressurized and inert process stream coming from the SVE blower. The challenge of moisture and solids entrained in the gas was solved by adding inline liquid knock out pots as well as solid separating filters. An automatic liquid drain system was also installed that allow the liquids to be pumped out of the KO pots and filters without the need to shut down the process system. Envent has operators onsite 24/7, to ensure the equipment is operating at peak performance and to log all compliance data to meet and exceed all regulatory standards.

Benefit

Envent’s solution to this logistical and regulatory challenge provided immense benefit to the landfill by allowing the facility to maintain environmental compliance and continue operating at full capacity. The system enabled the plant to avoid all environmental violations and maintains a safe working environment for its employees and the public.

 

Mobile Multi/Dual Phase Extraction Pilot Test


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


Challenge

A customer removed 50′ of 60″ ducting which contained NOx. The facility is located next to a major highway and bridge in the California Bay Area. Envent provided vapor control on the NOx so it did not produce a toxic orange cloud over the heavily populated area while the customer was removing the ducting.

Solution

Envent connected a 2,000 cfm blower to the 8″ flange connection on top of the ducting provided by the facility. 8″ connections were provided at multiple locations. Envent provided (3) re-circulation liquid scrubbers, ESCRUB 6000’s, in order to mitigate the NOx in the vapor stream. The first ESCRUB’s were filled with a sulfamic acid solution. The second was filled with a caustic solution. And the third was provided as a back-up unit on standby to be used if need with the sulfamic acid for NOx. Lastly, the cut pieces of ducting were forklifted to a hooch for storage while they were cleaned and prepared for disposal. Envent connected to the hooch via a fitting provided by our customer to scrub vapors while the ducting was cleaned.

Benefit

The facility remained in compliance with the BAAQMD due to Envent’s engineered solutions safely removing the NOx from the ducting. The heavily populated area remained safe while the ducting was removed, cleaned and disposed.

 

 

Gulf Coast Refinery Changing Focus


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


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.

 

 

Request a Quote

    How can we help?

    Services

    Skip to content