Cimarron’s senior technical staff gave presentations for the 2022 Onshore Wellsite Facilities Conference held in Houston, TX on September 20-22, 2022. Mr. James Sidebottom, Senior Technical Advisor at Cimarron, gave a presentation regarding vapor recovery units (VRU).
This very informative talk (about 30 minutes) is well worth your time if you work with VRUs. In his talk, Mr. Sidebottom starts by giving valuable technical information on vapor recovery units (VRUs). He then discusses a case study of a how a VRU system’s uptime was increased from a low of 82% to 99% runtime by using the latest advancements In VRU real-time telemetry to achieve ultra-high performance.
You can view the talk on YouTube at https://youtu.be/d8iolSj1NZE
Below is a summary and key information from the presentation.
Since the early 1950’s, VRUs have been used to efficiently recover natural gas vapors generated from standard oil and gas production and biogas processes. Selling this gas or using the gas as a useful fuel reduces venting and flaring and increase profits. For the oil production upstream and midstream industry, VRUs are used to capture flash gas from storage tanks, vapor recovery towers or other pressure vessels (e.g., heater treaters). Multiple compressor types are available based upon the needed application. These include oil flooded screw, rotary vane and vertical reciprocating compressors, available as natural gas or electric drive packages. The most common VRUs used by Cimarron customers are oil flooded screw compressors and rotary vane compressors.
Cimarron customers want to maximize VRU runtime to reduce air emissions (venting/flaring) and to increase profits from the recovered gas streams.
Actionable Remote Monitoring
Advances in technology allow operators to remotely monitor their operations and equipment. This has resulted in large amounts of data streaming into an operator’s monitoring system. But lots of data without review or action does not improve operation of a VRU. Sytelink360TM, Cimarron’s Actionable Remote Monitoring is used to increase the uptime for VRU. Cimarron’s system includes the following to ensure greater VRU runtime:
- Correct, informative data is collected to obtain the root cause of issue.
- Appropriate review and interpretation of data
- Meaningful and timely action is taken to correct the issue
The talk highlights a case study that used Sytelink360TM, an Actionable Remote Monitoring system for an oil and gas production facility located in New Mexico. The facility used remote monitoring and appropriate action to improve VRU uptime. The runtime improved from a low 82% uptime to 99% uptime.
The VRU using Cimarron’s Sytelink360TM Remote Monitoring system was designed to recover 1 million standard cubic feet per day (MMSCFD). The increased uptime (an additional 17% uptime) at 1 MMSCFD resulted in the following improvements:
- 1 days extra runtime per month.
- Value of additional gas recovered was $13,566 per month in 2021 (based on gas price of $2.66/MSCF).
- At $8.71/MSCF of natural gas equates to $44,421/month increase in gross revenue (October 2022 natural gas price).
- Additional 5.1 MMSCFD per month recovered by VRU.
- Reduced emissions by 68,000 tons CO2e/year (primarily methane that would have been vented).
Other topics discussed include the following on VRU applications:
- Most common VRUs used for oil gas facilities include flooded screw compressors and rotary vane compressors.
- Vapors typically recovered are from storage tanks, vapor recovery towers (gas boot), and heater treater flash gas.
- Recovered gas typically has higher specific gravity (mole weight) than sales gas.
- Variable frequency drives (VFD) are commonly used and results in more flexibility in capacity control.
- Operate screw compressors at 230 to 250 degrees F. This is important for gas dewpoint considerations.
- Run the VRU continuously, even if it stays in recycle mode.
Dewpoint and VRUs
The dewpoint of the natural gas recovered is one of the most important factors that can affect VRU performance. The dewpoint is the temperature at which liquids begin to condense from the vapor phase of a gas stream.
Dewpoint considerations include:
- Natural gas streams encountered in oil and gas operations tend to be higher specific gravities of 1.2 to 1.5 (34 – 43 lbs/lb-mole) and are rich with hydrocarbons that can condense out at lower operation temperatures.
- Maintain gas temperature during the compression cycle at 25 to 30 degrees F above the gas dewpoint temperature to avoid liquids condensing in the wrong place.
- Use a site-specific/equipment-specific gas analysis as input for VRU sizing/design. This alerts the VRU supplier about the expected dewpoint of the gas to be recovered.
Summary and Conclusions
Vapor recovery units (VRU) are effective in recovering natural gas vapors from oil and gas operations. Sending the recovered gas to a sales pipeline or using the gas as a useful fuel reduces air emissions and increases profits.
The typical VRU used in oil and gas operations uses a flooded screw compressor or a rotary vane compressor. VRUs are commonly equipped with variable frequency drives (VFD) and result in more flexibility in capacity control.
Using a Cimarron’s Sytelink360TM remote monitoring system allow operators to remotely monitor their VRUs resulting in increased VRU uptime. Sytelink360TM, an actionable remote monitoring system, requires collection of the correct data, appropriate interpretation of the data, and timely action taken to correct the issue.
Recovery of gas vapors with higher specific gravities requires VRU suppliers to consider the dewpoint of the recovered gas. VRUs should maintain the gas temperature during the compression cycle at 25 to 30 degrees F above the gas dewpoint temperature. This is required to avoid liquids from condensing in critical parts of the system. A site-specific gas analysis should be used to size a VRU.
Cimarron – Who We Are
Cimarron’s vision is to work with our clients to create a cleaner environment.
The company engineers and manufactures environmental, production and process equipment for the upstream, midstream and downstream energy industries, as well as environmental control solutions for biogas at wastewater facilities, digester tanks and landfills.
Cimarron offers our customers the know-how and environmental expertise to meet the environmental standards of today and tomorrow. Cimarron is committed to bring value to the Energy industry and their shareholders based on our financial strength, experienced personnel, and engineering capabilities.
As a company, we thrive every day to make a difference through innovation (e.g. ESG), customer focus, and operational efficiency. In addition to being present in all major regions in the US, Cimarron serves more than 45 countries around the world, ranging from offshore to desert. From key operational centers in the United States, Italy and the United Arab Emirates, Cimarron offers ongoing service and support through its own field service personnel and strategic third-party partners, creating a cleaner environment for our customers and their shareholders.
Since its founding in the mid-1970’s in Oklahoma, the company’s product offering has expanded from production equipment to include the largest line of environmental solutions that capture or incinerate fugitive vapors. With the acquisitions of HY-BON/EDI in 2019 and AEREON (including Jordan Technologies) in 2020, Cimarron has added strong brands, products, and services to its portfolio.