Scrubber Utilization and Maintenance at a Mid-Western Facility

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.

 

 

Vapor Control on Temporary Storage Tanks Requires Real Time Analysis

Portfolio Categories: Vapor Control.

Challenge

Envent was contracted to provide vapor control on two temporary storage tanks placed at a recovery and recycle area. The system abated vapors from temporary tanks that held rinse water. The water contained low levels of VOC founded in the vac truck rinse water and the roll-off bin rinse water. This project required a close analysis of the different parameters since the vapor flow and VOC’s concentration had a great variability. Normally Envent provides once/daily monitoring for a certain amount of time until the system becomes idle, then adjusts it to weekly monitoring. In this case, this was not an option since the inlet was continuously changing.

Solution

There was a need to select the equipment accordingly to handle the vapor flow and products. Calculations were required every time the water recovered showed distinct components and/or ppm concentrations. If the concentration increased to a certain percentage, the amount of carbon, or even the system arrangement, would need to be reevaluated based on the SCAQMD permitted limits and the adsorption capability of the material used. If needed, depending on the pollutants presented a different type of carbon would be used. Envent provided two EVAC 2000 SCAQMD permitted vapor control system pre-loaded with 1000 lbs of carbon in each vessel. In addition, Envent procured two 500 BBL temporary storage tanks.

Benefit

Envent always tries to adapt each project to the equipment and permits available so that their clients get the system that suits them the best. Due to the uncertainty of this project, our major concern was how to provide a cost-effective solution continuously and, at the same time, guarantee compliance with the emission limits.

 

Envent helps Louisiana Refinery stay Environmentally Compliant

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

Challenge

A major oil and gas refinery in Louisiana was fast approaching on a major turnaround where the coker flare and adjacent unit would need to be taken down for maintenance. The adjacent unit was home to the flare scrubber where all daily vents from multiple units, such as the Coker, Diesel Hydrotreater, Sulfur Plant, Sour Water Stripper, and Gasoline Hydrotreater, came from. Having this unit shut down along with the specially designed flare would mean that all vents would need to be routed to a backup flare, one that was ill-equipped to handle the “sour” vapor streams of the plant. The option to route the vents to their onsite amine scrubbers would cost the facility around $7 to $8 MM in production.

Solution

Envent’s technical team along with project engineers worked with the refinery to scope and design a scrubber system that would perform H2S and SO2 removal before vapors would be routed to their backup flare. Envent sized and built blowers that allowed the vent header to retain its day to day pressures while routing vapors from their flare header to Envent’s temporary scrubber system. The system was equipped with High-Pressure KO Drums, HP Stainless Steel Caustic Scrubbers, Automatic isolation valves, temperature, and pressure transmitters and sensors. All equipment was installed per strict MOCs guidelines and Class I Div II location requirements. Envent provided a fully-manned operation with two technicians around the clock for the entire duration of the 30 plus day outage.

Benefit

The customer was able to keep the operation of their site’s amine scrubbers and save upwards of $8,000,000 in production cost, all while continuing to operate their main units during a planned shutdown. Envent was able to keep the refinery environmentally compliant by ensuring that all vapors vented to their backup flare were below ~5ppm of H2S/SO2.

Northern California, Mobile Water Treatment – Multi Phase Extraction

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

Challenge 

Contaminated water at a Northern California Refinery where groundwater must be extracted before it enters the bay.  There is a series of groundwater wells and pumps that maintain hydraulic control of the area’s sub surface water system and prevent the contaminated water from reaching the Bay. The source of contamination was a Methyl tert-butyl ether (MTBE) tank with an underground transfer pipe that leaked. This leak was pretty substantial in size causing a fairly large underground plumb of MTBE. We have been onsite since 2008.

 

Solution

Multi-Phase Extraction utilizes a high vacuum blower to pull a mixture of both liquid and vapor from an existing ground well. The high vacuum extracts water and vapor until ground water level drop allowing a high vacuum to be pulled on the surrounding contaminated soil.  Extract a liquid/vapor mixture separate them then send the liquid to our existing water treatment system and destroy all hydrocarbons extracted to speed up the soil remediation process.  We provided the customer with a 450 SCFM Liquid Ring DVT blower and an EMTOS 2000.

 

Benefit

Envent’s engineered multi-phase extraction, water treatment and vapor abatement system continues to be successful at cost effectively removing and treating both the groundwater to NPDES standards and the vapor stream to BAAQMD and EPA standards.  The oil refinery is in full compliance and impact on the environment mitigated.

Envent performs Soil Vapor Extraction near Public School

Portfolio Categories: All.

 

Challenge

A customer was in need of a soil vapor extraction system for a project located within 2,000′ of a public school for a three month pilot project duration. The system was needed to scrub the following VOCs: BTEX, TCE and PCE. Upon successful completion of the pilot project, our customer could then determine the need for a permanent system. Given the close proximity of sensitive receptors (children), the customer had to be assured our system would perform.

Solution

Given Envent’s experience in Soil Vapor Extraction and already having a portable various locations air permit on-hand, we had the solution on the shelf ready to go. A fully self-contained SVE scrubber trailer was dispatched to the job site. This one trailer had everything needed to pull vapors from below ground, pass through lead/lag carbon vessels and vent to atmosphere through a 14′ vent stack. A chart recorder logged VOC concentration, and daily monitoring samples were drawn from sample ports at the inlet, midpoint and outlet of the scrubber. An on-board blower was throttled to provide the best flow rate, and power was provided by an electrical tie-in to existing job power pole.

Benefit

The benefit to the customer was the ability to test the equipment sizing and flow capabilities prior to spending capital on an unproven system. Envent’s system gave the customer the confidence they needed to move forward with the construction phase of their project. This project complied 100% with local regulations and the regional air permit. All emissions data logged during the project was presented to the customer in a project closure report.

Washington Refinery – Sulfur Loading Rack Vapor Control

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

 

Challenge

A refinery sulfur recovery loading rack was giving off foul/hazardous odors to truck drivers and personnel located in immediate surrounding area of sulfur recovery unit (SRU) during truck loading events. Truck drivers inside the refinery were required to dawn SCBA’s and load trucks with truck dome hatches open. They had to visually validate fill levels during loading events to prevent overfilling. Envent was requested to quickly find a solution to eliminate foul/hazardous odors and maintain an automated/unmanned long term solution, keeping truck drivers and SRU personnel safe from high H2S vapors during truck loading.

Solution

Envent engineered an unmanned, automated vapor control solution tied into existing plant power. Envent system consisted of an interchangeable truck dome hatch with windows for truck drivers to verify loading events. A movable vapor line arm creating 500 CFM of vacuum was then steam traced and fit up to a skid mounted ESCRUB 1000-P (knocking out sulfur fines) followed by ESCRUB 1000-SS Re-Circulating Packed Column Scrubber filled with an H2S scrubbing liquid media (removing all H2S).

Benefits

Envent’s engineering department was able to custom design and build an unmanned vapor control solution alleviating refinery engineering manpower. Furthermore, Envent engineering streamlined a significant portion of an otherwise lengthy refinery MOC process by supplying system design specifications and drawings for Envent equipment (which is designed and fabricated in-house by Envent). Envent removed an ongoing odor control concern by creating a long term solution within weeks of design inception. Ultimately, Envent was able to eliminate H2S hazards all together; knocking inlet vapors from 1500ppm H2S to 0.0 ppm H2S.

Truck drivers, refinery operators and contractors are now working freely in the SRU without any odors or H2S hazards.

 

Vapor Control of Fuel Gas Recovery Line Provides Client Quickest Turnaround Ever

Portfolio Categories: Turnaround Services and Vapor Control.

 

Challenge

A client asked Envent to help them to do the vapor control on the fuel gas recovery line at their refinery during their hydrogen plant turnaround event. As the hydrogen plant was being taken offline, the refinery fuel gas consumption would decrease, causing an excess of fuel gas. The excess capacity of the fuel gas line that Envent needed to control was as high as 3 million standard cubic feet per day, while also maintaining compliance with Envent’s Alternative Monitoring Plan from the Environmental Protection Agency.

Solution

Extensive engineering efforts were involved to overcome the customer’s challenge. A pressure loss study for two parallel streams of high pressure fuel gas was conducted to size regulator systems. Project-specific upgrades were implemented on the thermal oxidizer control systems. Control and isolation valves were designed into the system during a project PHA to handle unforeseen process conditions. Specialty, auxiliary detonation arrestors were installed to mitigate additional hazards; analyzers were installed to monitor key process conditions.

Benefit

With this flexible, but thoroughly engineered solution, the fuel gas vapors were treated successfully without any environmental or safety incidents. Knowing that their fuel gas recovery system was in good hands, our customer completed their turnaround faster than it had ever been done before.

 

 

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