Cost-effective turnaround for an Olefins Unit completed safely and on-time

Cost-effective turnaround for an Olefins Unit completed safely and on-time

Portfolio Categories: Vapor Control.

Challenge

During a turnaround for an Olefins Unit, a customer tasked Envent with providing a vapor control system to process stray hydrocarbon vapors while their normal vapor recovery system was down for maintenance. The customer’s unit superheaters were to be shut down for three months, and without a proper solution in place, the customer would release extraneous VOCs into the atmosphere violating emissions regulations. Therefore, it was important that an effective, low-cost solution would be able to continuously remove VOCs for the full duration of the project.

 

Solution

Envent implemented a two-stage system for this vapor control project. In the first stage, Envent used a scrubbing system that utilized a liquid media and activated carbon to target VOCs. This was designed to strip low concentrations of VOCs from the customer vapor streams. Envent utilized a downstream blower to pull vapor through the scrubbing system. Not only did the blower direct flow to the scrubbers, but it provided a slight vacuum on the customer system to prevent excess gas buildup and pressure release to atmosphere. Two trains of scrubbers were set up so that once media became spent, Envent could divert flow to a scrubber with fresh media. During this process, Envent utilized an FID monitor to keep track of VOC concentration levels entering and exiting the scrubbers. After the first stage of maintenance was completed by the customer, VOC concentration levels increased significantly. Therefore, Envent switched over to a thermal oxidizer system for the second stage of the project. The thermal oxidizer is designed to handle high concentrations of VOCs and combust them at a 99.9% destruction efficiency. With its built-in blower, Envent could pull significant vacuum on the customer system while handling the increased concentration of VOC from the customer side. Envent continued operation of this system until the customer maintenance was complete and the Olefins-1 Unit superheaters were back online.

 

Benefit

This customer benefited from Envent’s solution in a variety of ways. First, the customer was able to avoid releasing VOCs directly into the atmosphere. The significance of this allowed the customer to stay in compliance with emissions regulations and prevent environmental damages. Secondly, Envent’s experienced crew enabled the customer to focus efforts on completing the superheater maintenance in a timely manner rather than waste time and energy manning an additional set of tasks. Envent maintained and operated the implemented system for several weeks safely without issue. Lastly, Envent’s solution was both effective and low-cost. The equipment provided was designed to meet the functions of the project without over bidding materials. Additionally, the complete reduction of stray emissions saves the customer money by avoiding fines from violations. Overall, Envent’s simple solution proved to be highly efficient and cost-effective, and the Olefins Unit project was completed safely and on-time.

Engineered Solution for Gulf Coast Refinery

Portfolio Categories: Vapor Control.

Challenge

Due to the recent pandemic striking the world, a gulf coast refinery adjusted their refining process to allow them to continue production. They found a surplus of C4’s (n-butane, isobutane, etc) that typically sell with ease. During this process, multiple variations of C4’s are made from a single process. 1-3 Butadiene demand remained high, and had no problem selling. The remaining C4’s, however, had no demand at the time, and needed to be disposed of. This would allow their production to continue without delays.

Solution

This refinery reached out to Envent to engineer a solution. Based on their desired flow rates, Envent mobilized two of the largest (70MMBTU/HR) mobile thermal oxidizers available in the United States to meet the refinery’s requirements. Envent also custom designed a manifold to add safety features and pressure regulators to ensure consistent flow. The project is still running today as the country recuperates.

Benefit

The benefit of Envent providing this service is the refinery was able to continue creating 1-3 Butadiene that remains in high demand, and allow them to continue their income, stay in business, and provide jobs for their employees. Had the refinery needed to stop processing, the entire plant would shut down. Envent benefits in the same way, while also feeling a certain accomplishment being an essential business in the trying times of today.

West Coast Pipeline Purge Vapor Control

Portfolio Categories: Vapor Control and Vapor Scrubbing.

Challenge

A West Coast pipeline company contacted Envent Corporation to provide vapor control services during a high-pressure pipeline purging operation. Traditionally, large carbon adsorption vessels are proposed for this type of project. However, due to the elevated operating pressure, using standard atmospheric vessels would have required costly high-pressure-rated alternatives or protective systems to prevent failure under pressure.

Solution

Envent’s engineering team evaluated several approaches during the planning phase and ultimately proposed a customized vapor control solution leveraging a high-flow carbon scrubber system integrated with high-pressure components.

Based on an absorption model developed in-house, our engineers calculated vapor load and system sizing. The final system included:

  • A trailer-mounted BD 6000 vapor scrubber, ideal for mobile vapor scrubbing and pipeline degassing

  • A high-pressure regulator to reduce inlet vapor pressure for safe entry into the scrubber

  • A high-pressure knockout pot to remove entrained liquid during the purging process

This configuration enabled effective control of pipeline vapor emissions while maintaining equipment safety and integrity.

Benefit

By utilizing Envent’s engineered vapor control solution, the client completed their pipeline evacuation safely, efficiently, and at a significantly lower cost than traditional high-pressure vessels. This project reinforced Envent’s role as a trusted provider of custom pipeline degassing services, pressure vessel vapor control, and industrial vapor scrubber systems—ensuring safety, compliance, and cost-efficiency in complex operations.

Envent provides turnaround support for emergency shutdown

Portfolio Categories: Turnaround Services and Vapor Control.

Challenge

A Gulf Coast Refinery was faced with an emergency shutdown on one of their reactors, the catalyst was spent and needed immediate replacement, and it needed to be completed in time for their Alkylation unit was to be brought back online. The reactor needed to be cleaned in three separate phases in order to neutralize the catalyst and prepare the system for maintenance. The system would be at high pressures (>200 PSIG), high temperatures (>320F) and would contain Hydrogen at 90%, along with inbound sweeps of Hot N2. The work needed to be scoped, planned and executed in around 7 days in order to meet the desired timelines.

Solution

Envent worked with the site’s Turnaround planners and engineering team to properly scope a system that would handle the critical parameters, as well as be able to handle and process the changing atmosphere within the reactor. Envent mobilized the EMECS 70, the largest mobile thermal oxidizer in the US, the EMECS along with heat exchangers, regulators, NFPA approved Hydrogen flame/detonation arrestors, and ASME rated pressure vessels ensured that all conditions and phases of the project were dealt with. Envent operated the entire project with Field Supervisors, Project engineers, and the best equipment operators in the industry.

Benefit

The project was completed safely and in a timely manner, the customer was able to meet the deadline set forth by it’s turnaround schedule. The reactor was verified to be gas-free and safe for entry and inspection. Envent’s ability to provide turnaround support at a very short notice allowed the site to bring up a major Unit’s components at the same time without any delays, saving them costly delays in labor and production.

Northern California Waste Water Treatment Solution

Portfolio Categories: Mobile Water Treatment and Vapor Scrubbing.

Challenge

On Christmas Eve 2019 the citizens of a Northern California city woke up to a terrible rotten egg smell. The General Manager of the water treatment facility made a call to Envent around 2:30 p.m. on December 24th, 2019. He said he had a terrible rotten egg smell coming out of one of the digesters. Envent’s engineering team quickly sprung into action.

Solution

The engineering team put together a solution which would mitigate the H2S coming out of the digester. Our technician went to the site and the H2S in the vapor stream venting to atmosphere was at 3,000 ppm. The Water Treatment plant is located in a centralized neighborhood of homes. You could smell the H2S for miles. The team mobilized an ESCRUB 2000-SS and two each 2,000 pound vapor media vessels containing DARCO Carbon. by 9:00 p.m. that evening the smell was gone and the citizens of the Northern California City were safe and enjoying the holiday.

Benefit

The system has been functioning at the Northern California Waste Water Treatment Plant for three months now and everyone is very satisfied. The General Manager said, “I am thankful to Envent for its expertise in engineering and being incredibly responsive”.

Long Term Vapor Control Project in Southern California

Portfolio Categories: Vapor Control.

Challenge 

We have a long term project located in Southern California where we are providing vapor control for tanker trucks being loaded with crude. We decided to use a TO as the carbon spend rate will be very high. The unit is always on hot standby. The challenge of this project comes from the inconsistency of vapor composition and loading schedule. When a truck begins to load, a flood of high BTU vapors are sent directly to our unit. This would cause the unit to reach very high temperatures before the fuel management system could adjust.

Solution

We designed and installed an automated valve solution. This involved a pressure sensor that would sense when a truck began to load. This signal was sent to a UDC programmed with a proportional delay. The UDC would then output the signal to slowly and proportionally open an inlet valve depending on the pressure coming from the truck.

Benefit

This solution allows the unit to adjust to changes in process conditions automatically. After verification and testing of the automated solution, the unit can now provide unmanned vapor control for all truck loading activities.

Scrubber Utilization and Maintenance at a Mid-Western Facility

Portfolio Categories: Vapor Control and Vapor Scrubbing.

Challenge
A mid-west facility was under a time and regulatory constraint to reduce H2S emissions coming from a cold feed storage tank. There were many requirements that had to be met to sufficiently perform this job including having a high flow at the system. Envent had to figure out a way to knock out aerosol and oily carryover, and scrub H2S for an undetermined duration with no equipment failure.

Solution
Envent worked with the facility to provide a series of passive scrubbers, recirculating scrubbers, knockout pots, and blowers to adequately perform the job. Numerous studies were completed to consider pressure drop, clogging/plugging, spikes in LEL and H2S changes in seasonal patterns, including maintenance. Our Envent Engineers worked hand in hand with the facilities engineers to scope the project and account for any potential hurdles to maximize system performance and reliability.   

Benefit
Having the ability to provide engineering, equipment, and specialized technicians allowed the facility to meet the deadline of lowering their H2S. This also allowed them to continue operation. The extensive knowledge of scrubber utilization and maintenance provided by Envent gave the customer various operations to maximize performance. Without this acquired knowledge, longevity and equipment failure would’ve continued to present a challenge for the facility.

 

Envent Mobile Wastewater Solution Saves Client Time and Money

Portfolio Categories: Mobile Water Treatment.

Challenge

A local refinery had a large waste water tank that needed to be deinventoried and cleaned in order to change the service type. The water would either need to be treated on site or hauled off. Standard onsite treatment would take roughly 2 years at the rate they could discharge to the onsite system and the cost to haul it off would be exorbitant. Considering the volume and amount of contaminants in the water the decision was made to have the water pretreated for Benzene, TOC, Sulfides, NH3 & pH before being sent to the onsite system.

Solution

After Envent reviewed the analytics and performed bench tests, our Technical Project Manager and team of engineers put a solution together using solids and oil separation, filtration skids and polishing media. The water was treated down to the acceptable limits in order to be sent to the onsite treatment facility.

Benefit

Envent was able to successfully treat in roughly 2 months what would have taken the customer 2 years. We not only saved them time but also money, as cost to treat on site was considerably less than hauling the water off as hazardous waste.

 

 

Degas of Propane Storage Tanks in Toledo, Ohio

Portfolio Categories: Degassing.

Challenge

A refinery in Toledo, Ohio requested Envent to bring their propane storage tanks to an LEL level acceptable for personnel to make entry. Envent would connect their EMECS units to their connection point, and process vapors until the customer samples, and deems degassed.

Solution

This job proved to have many uncertainties not typically noticed at first glance of a normal degas. The Refinery identified early on there would be traces amount of liquid propane in the tanks, After further investigation and after Envent already mobilized to the job, The customer disclosed they weren’t sure how much liquid propane we could expect, but it could be up to 1700 barrels.

Envent couldn’t process the propane at full capacity due to several limiting factors. For one, every refinery wants to be a good neighbor, and Envent’s job location was across the street from a neighborhood. When increasing the flow, Envent’s units become very loud, and the refinery received noise complaints, to which they requested the units’ noise be toned down. Also, the EMECS units utilize an 8-inch connection to allow vapors to flow quickly into their system. Unfortunately, the connection to the tanks was 2-inch, causing a bottleneck on allowable flow, and slowing the project further.

Envent utilized a third-party nitrogen generator to further purge the tanks of LEL. Envent would pressure the tanks with 120psi of nitrogen, then process the vapors through the EMECS units. The customer would sample the tanks’ LEL levels, and if it was not an acceptable level, Envent would repeat the process.

Benefit

The lack of knowledge of how much liquid in the tanks proved a gruesome process. Envent knew of the trace amount of liquid beforehand, and brought their stand-alone propane vaporizers to convert the propane liquid to gas, allowing the EMECS units to process the vapors efficiently. The adjustment Envent made was simple: Keep vaporizing and monitoring pressure gauges until the liquid was gone. Once the liquid had been removed, Envent bypassed the vaporizers, and went direct to their units.

 Because of the flow restrictions, the only the approach that made most sense is to run the units at an optimal speed as to not make too much noise, but maximize flow. This was done by ensuring balance between both EMECS units remained at around 50% capacity, and pull off the 2-inch vapor line until the degas was completed.

After the initial removal of the liquid and vapor, nitrogen was introduced into the tanks using nitrogen generators. Within this manifold of propane tanks, there were a lot of places stubborn propane could sit. With this in mind, pressuring up the vessels would have to be a multi-step process, but is very difficult to know exactly how many steps it would take to lower the LEL. Our customer, Envent and their third party all worked in tandem to complete this process, pressuring up, burning the vapors, then sampling the LELs, until eventually, the tank’s LELs were lowered completely.

            Among all the scope changes and uncertainties, Envent handled them masterfully, and allowed them to gain this refinerys trust as an engineering-driven thermal oxidation company.

 

Effective Vapor Control to Reduce Nuisance Odor from Gas Pipeline to Surrounding Neighborhoods

Portfolio Categories: Odor Control and Vapor Control.

Challenge

An underground gasoline pipeline had a leak that went undetected for an unknown duration that caused leaching into the ground. As a result of the volume of contaminated soil, strong gasoline odors were detected in the area. Those nuisance odors were affecting nearby neighborhoods causing community concern and complaints.

Solution

Envent scoped out the project and provided a long term, high-flow vapor control solution. Based on the size of the affected area and the concentration of the vapors, Envent sized the system for enough flow to pull sufficient vacuum to capture all off-gassing vapors. Envent was able to strategically determine different areas to focus where the vacuum would be most efficient. Additionally, the engineering team was able to determine the carbon life expectancy to be able to limit the amount of carbon change-outs needed to keep operations running smoothly and uninterrupted. Considering the system would be operating near a neighborhood, Envent took into account minimizing noise pollution and utilizing an enclosed blower.

Benefit

Odors were no longer detectable surrounding the affected area. The system continued to run and between minimal footprint, low noise and NO odors, the results were a satisfied community. Work was able to be completed to remediate the contaminated soil and provide a full environmental cleanup.

Envent Provides Turnkey Dewatering Services for Electrical Substation Relocation

Portfolio Categories: Mobile Water Treatment.

Sphere Tank Degassing | Envent Corporation

Challenge

A general contractor was selected by a local utility company to oversee the relocation of an electrical substation. This process required the construction of several large power lines and installation of numerous underground vaults. The project was located 0.25 miles from the coast, so the water table was very shallow near the construction site. The underground work was going to require significant dewatering installations to allow dry subterranean construction. Due to strict environmental regulations, groundwater could not simply be discharged back to the ground. The groundwater removed for dewatering would also require treatment and to be discharged to a local Publicly Owned Treatment Works (POTW). Envent was contracted to provide turnkey dewatering services with dewatering installation, dewatering permitting, mobile water treatment solutions, water discharge permits, and equipment operations/monitoring.

Solution

The groundwater will continuously regenerate according to the characteristics of the soil and the water table. Unfortunately, these properties were poorly defined for this project. If the majority of the soil was dirt, then groundwater would flow easily and quickly (leading to fewer, larger pumps). However, if the majority of the soil was clay, then the groundwater would not flow easily (which requires more, smaller pumps). Soil boring logs were obtained to estimate the height of the water table, which was used to plan the depth of pump installation in dewatering wells. Additionally, the soil boring logs report the general soil characteristics to plan quantity and size of pumps required. Estimated flowrates and practical treatment rates were used to obtain water discharge permits to the local sewer and size the treatment system accordingly.

Benefit

With this flexible, but thoroughly engineered solution, the customer was extremely satisfied with dry subterranean construction conditions. As Envent helped mitigate wet subterranean soil conditions, the general contractor saved tens of thousands of dollars in reduced cost and was able to complete work ahead of schedule. The utility company was furthermore able to complete the project under-budget and ahead-of-schedule.

Major Turnaround Success for a Large Gulf Coast Refinery

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

Challenge

A large gulf coast refinery was planning major equipment turnaround on multiple process units. While defining the scope of the work, they estimated that their Flare Header would quickly reach maximum capacity with vent gas from the process unit depressure and decontamination steps. The environmental department required the project to limit all emissions to the flare due to increasing regulatory scrutiny for flaring. If the refinery solely relied on their FGR system the turnaround delays would cause the project to be 7x longer and have enormous cost to the refinery operation.

Solution

The refinery selected Envent to design and engineer a vapor control & flareless turnaround system to help them meet their compliance limits, project schedule, and turnaround budget. Envent determined the feeds and makeups for the process units in question and the schedule at which Envent would see different vapor compositions. Envent selected various equipment from their fleet of vapor control solutions to mitigate each phase of the turnaround process. H2S concentrations of up to 100,000 ppm required specialty liquid scrubbers. Steam outs required condensing and knockout equipment. Unique hydrocarbon compounds required upgraded detonation protection equipment.

Benefit

The refinery congratulated Envent for an extraordinary job on this project as they had exceeded their compliance initiatives. Instead of hundreds of thousands of dollars in fines, they paid zero. Instead of the 95% destruction efficiency common to flares, they had >99.99% destruction efficiency common to Envent’s thermal oxidizers. The refinery completed their turnaround ahead of schedule, helping them above average profits for the year. Most important of all, no safety/compliance/equipment incidents occurred.

 

 

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