Washington Refinery – Sulfur Loading Rack Vapor Control

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.

 

 

Pipeline Clearing + LPG Bullet Depressurization and Degas

Portfolio Categories: Degassing and Vapor Control.

Challenge

A customer in the Gulf Coast engaged Envent with the need to depressure and clear a pipeline running from its refinery to 3.5 miles South of refinery for an emergency repair and inspection. The customer also brought up the need to a depressurization and de-inventory for an LPG Bullet tank during the same time frame.

Solution

Envent, with efficient emergency response and state-of-the-art equipment was able to provide a cost effective solution that not only cleared the pipeline, but also de-pressurized and degassed the LPG bullet with the same crew and EMECS, one after another. This in turn helped our customer perform necessary maintenance and repairs to the pipeline as well as LPG Bullet tank.

Benefit

With Envent’s response time, it not only provided the depressure and degas service for the customer, but saved them time and money, cutting each job in half and performing a 2-in-1 service (1 mobilization, 1 demobilization). With the time that Envent saved them, they were able to perform additional maintenance to pipeline that might not have been available had we not responded.

 

Envent Provides Vapor Recovery System to Underground Toxic Cleanup

Portfolio Categories: Odor Control and Vapor Control.

Challenge 

A chemical manufacturing facility in the Southeastern US had a large underground cleanup of toxic chemicals that had been spreading underground for many years. They had a design for the tent enclosure that the heavy equipment would be working in but needed a vapor recovery system to make sure none of the hazardous vapors affected any of the workers in the area or the nearby town. The system had to keep contaminant levels below one part per billion to stay within specs.

Solution

Envent’s Engineering team were able to provide custom designed redundant 5,000cfm systems utilizing over 100,000lbs of carbon at one time to keep the job on schedule and within discharge limits to keep everyone safe. Envent also provided additional equipment to provide fresh air for the large excavators’ engines so the same contaminants didn’t destroy the expensive equipment and incur large repair bills. Envent also provided custom piping to duct out the high temp exhaust from the equipment. With turn key services, Envent also provided backup power for the whole site along with temporary large industrial Air Conditioners to keep the inside of the tent at a safe level for workers even with 100+ degree heat with high humidity in the middle of summer.

Benefit

Envent was able to provide a safe redundant turnkey system that helped our client get the job done and provide a safe area for the workers performing the work in Hot humid weather. Envent’s top level engineering and project team was able to adapt to multiple changes in scope on the project and get design done and equipment to the site in minimal time to minimize delays and keep the project moving forward. This project was completed with no violations from DTSC even with the very strict limits placed on outlet of the system.

 

Envent Engineers ensure Environmental Compliance

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

Envent Engineers ensure Environmental Compliance During Tank Cleaning

 

Challenge

Envent provided vapor control on 5 temporary frac tanks during a tank cleaning. The source tank was emptied of a slop oil mixture. The product was going to be separated by a centrifuge into water, oil, and solid components. The temporary tanks in use accepted water/oil outputs and contained a heavy oil/sludge input mixture. The main technical challenge in this project was ensuring that the passive carbon system would not be spent at a faster pace than what was expected, and possibly result in compliance violations. The amount of product being pumped into the frac tanks would vary along the vapor control and could not be predicted. In addition to trying to comply with our emission limits, we had to be sure that all the system was the most cost and time effective solution.

Solution

Once the scope was outlined, calculations were performed to infer the amount of carbon needed based on the vapor pressure of the tank mixture. After we gather all the products data, we were able to design a carbon system according to the type of product in the tanks, the number of tanks, the pumps output, etc. Envent used a system of two EVAC 2000 (2,000 lbs carbon vessels), including a flame arrestor, interconnecting hoses, and tank fittings.

Benefit

SCAQMD permits are particularly complex for centrifuge operations and the compliance of centrifuge projects requires attention to detail. Envent engineers experience was valuable when laying out the equipment in the most efficient way so that in case of an equipment failure we would still comply with all the SCAQMD permit limits.

 

Envent helps to provide a solution to handle Liquid Ammonia

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

Envent helps to provide a solution to handle Liquid Ammonia tank skid evacuation

Challenge 

A customer tasked Envent to help evacuate an Ammonia tank skid and the surrounding piping so that multiple valves in the system could be replaced safely. Envent would have to provide a solution to handle liquid ammonia, associated temperature issues, and chemical hazards.

Solution

Envent provided the customer with a High Pressure Regulator, a SS Knockout Vessel, and an EMECS 20 Thermal Oxidizer all connected by SS Hose. The customer system had an initial pressure of 200 psig which was reduced to a manageable pressure by the High Pressure Regulator. However, as pressure decreased, the temperature of the vapor stream would decrease as well, resulting in freezing of the liquid ammonia. To combat this issue, a constant heat source was applied to the SS Knockout Vessel, thereby preventing the ammonia from freezing and allowing it to vaporize sufficiently. The ammonia vapors were routed into the EMECS 20 Thermal Oxidizer where they were combusted with over 99.9% efficiency. Using the EMECS 20 onboard blower, Envent maintained a vacuum on the system so once ammonia levels reduced to nearly zero, the valves could be removed and replaced. The constant vacuum helped to prevent any release of ammonia vapor into the atmosphere, and eliminated worker exposure to the chemical. The process was continued until all valves were replaced safely.

Benefit

Using Envent’s solution allowed the customer to complete their maintenance work in a timely manner. Additionally, using Envent’s thermal oxidizer significantly reduced the amount of emissions that the customer would create. Therefore, the customer was able to proceed with standard operations immediately and cut costs significantly.

 

Degassing of an LNG-powered Freight Vessel

Portfolio Categories: Degassing and Vapor Control.

Envent Corporation | Marine Vapor Degassing

CHALLENGE 

A customer has tasked Envent to create a temporary system allowing for the degassing of an LNG-powered freight vessel while it docks in port to remove cargo. The solution would allow the customer to continue standard operations without delay, clear unwanted vapors from within the fuel tanks, and maintain compliance with Environmental Protection Agency regulations.

SOLUTION 

Envent supplied the customer with an EMECS 70, the industry leading mobile thermal oxidizer unit, as well as cryogenic-rated SS hose, a knockout drum, and a high-pressure regulator. The freighter has two 900 m3 LNG tanks each containing trace amounts of liquid LNG and pressurized vapors. The process stream was routed through the cryogenic-rated SS hose down to the knockout drum allowing for the vaporization of LNG to a gaseous state while simultaneously increasing its temperature from subzero to suitable levels. Fire water was run past the knockout drum in order to aid with the heat exchange. Vapors were 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 depressured.

BENEFIT 

Envent’s depressure 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.

 

Envent helps in overcoming local Environmental regulations

Portfolio Categories: Case Studies, Degassing, and Odor Control.

Odor Control Units from Envent Corporation for Pipelines, Refinery, Sewer, Industrial Tanks and emergency response

Challenge

A large Oil and Gas customer needed to perform much-needed maintenance on one of their Crude Oil tanks in the North East. The processes of degassing and cleaning crude tanks are relatively common throughout the industry; however, this project inherited some issues that first needed to be addressed. To start off: the crude oil contained a high level of H2S ( 1500ppm), the sulfur and entrained mercaptan made it so that the odors of this tank would be immediately detectable to any residents in the area. The composition of the crude was also very light, meaning that the tank would liberate vapor very quickly, this vapor could easily enter the atmosphere and dispense among the surrounding area. The risk for exposure to H2S to the neighboring residents would also be extremely critical. The tank was located in a small terminal, where it was surrounded by a residential subdivision to the south, a retirement community to the north, and a large community center to the east. The concern for public opinion in a region where Oil and Gas companies are not seen favorably was also important, this was made clear to them when their last maintenance event at the site was met with public complaints, and local camera crews in regards to the odors during the event. To worsen the situation: the local environmental department had limited the vapor control devices allowed to only one option: Carbon Adsorption.

Solution

Envent Corporation worked with our customer’s Engineers, and Compliance Specialists in order to develop a plan that not only met the needs of the site to be “Good neighbors” but also addressed their safety concerns while expediting the project to minimize the downtime for the tank. Envent developed a liquid/carbon scrubber system that was capable of adsorbing all of the VOCs that saturated the vapor space in the tank. The system was capable of a high volume flow of ~4,000 SCFM. This flow kept the tank seals and roof openings from reliving any vapors onto the atmosphere. Multiple monitoring devices were placed around the tank to ensure that no vapors were escaping around the tank or any processes. Liquid phase chemical media was used to safeguard the activated carbon, while a multi-port manifold was used to divert and manage flow to specific scrubber trains. A nitrogen suppression system was also engineered for the safety of the crew and integrity of the system. Lastly, Envent also prepared multiple support structures for media and chemical change-outs to ensure the system was designed so that no downtime would be had during the project.

Benefit

Envent’s solution kept the vapor space in the tank safe from the initial vapor space opening until the tank was deemed gas free and safe for entry. The system adsorbed well over 12,000 lbs of VOCs while maintaining a 100% DRE throughout the multiple scrubber trains. While the tank was estimated to reach a gas-free state in about 3 days, degassing was completed in just 26 hrs. This rapid completion of the degas allowed the customer to move-up scheduled work, saving them extra costs from the multiple contractors who were on standby. The project received no complaints from the neighbors, and no attention from the local media, which in this case; is very good news.

 

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 in the Port of Brownsville; the tank was a mid-sized High RVP Gasoline tank with a pipeline feeding into it. The tank was due to come out of service for an API 653 inspection. The customer as well as cleaning company had assumed the tank to be product free, but upon closer inspection, realized that there was over 1 ft. of product remaining in the tank toward the middle of the sump and water draws.

 

Solution

We were able to work with the customer as well as cleaning company to provide vapor control and degas capabilities around the clock until the remaining product was completely removed and tank was degassed to below their permit requirements <10% LEL.

 

Benefit

With Envent Corporation, although we faced a few small road bumps along the way, we were able to come through and provide excellent customer support and satisfaction, finishing the job under the proposed amount of time and working with the customer as well as cleaning contractor to finish the job. At Envent Corporation, we are always prepared to adapt and overcome when faced with adverse situations and projects. Our three main priorities are 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.

 

 

Request a Quote

    How can we help?

    Services

    Skip to content