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.
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.
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
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.
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.
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.
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.
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.
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
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
A California refinery had a need to load gasoline, ethanol, and other high vapor pressure materials (classified as MVR products) onto barges. MVR products are required to have vapor control on them during transfer onto the vessel. The loading terminal is not equipped with any form of vapor recovery device on the dock. Without the ability to load product, the refinery and terminal will miss out on potential profits for the sale of the MVR products. A temporary solution is needed to control vapors during loading events while maintaining compliance with strict US Coast Guard regulations (33 CFR 154 Subpart P).
Envent implemented a vapor control system designed specifically for compliance with USCG regulations. The industry leading EMECS thermal oxidizer was utilized along with Envent’s Dock Safety Unit (EDSU). Envent engineers worked with various crafts to facilitate the installation and testing of the equipment per USCG regulations. These regulations limited distances from the dock, pipeline size, PRV/VRV requirements, and many more. Lastly, Envent received a certification letter from an approved third party USCG representative confirming compliance with 33 CFR 154 Subpart P. A copy of this letter is filed in the office of the terminal manager.
The refinery terminal was able to load MVR products onto ships and barges at a flow rate of 7500 BBL/hr. The terminal vastly increased their profit margins by having a faster, better, and more cost effective route for moving product. Choosing Envent proved to be a great choice for the refinery, as it will make the terminal company millions over the next few years.
A customer was facing EPA fines in the tens of thousands of dollars per day for the release of H2S and VOC’s to atmosphere from a tank not permitted to contain H2S-laden material. The customer reached out to Envent to solve the problem within a short deadline of three months.
Envent was able to design and construct a specialized vapor control system that stripped the vapors of a sticky aerosol residue and pull the H2S-laden vapors through a bank of Envent ESCRUB 1000 circulating scrubbers. This system operates continuously at 1,000 CFM and treats 7,000 PPM of H2S.
For nearly three years, Envent has operated this system with ZERO breakthrough of H2S and ZERO safety incidents. Envent crews have operated this system safely and efficiently, day and night, 24/7/365. The onsite Envent technicians have been able to optimize the system to utilize as few consumables as possible, lowering the costs to the customer. The customer was able to avoid EPA fines and now has the time to design and construct a permanent process unit slated for construction in 2020.