Oil & Gas Sealing Solutions with a Low Temperature FFKM
Technology advancements and new-to-world discoveries are constantly creating a new series of challenges for seal materials in the Oil and Gas industry. In today’s environments, seals are being pushed to perform in temperature, pressure and chemical extremes never before thought to be obtainable with rubber products. Application pressures exceeding 20,000 psi, service temperatures ranging from -40°F to upwards of 500°F, and exposure to some of the most aggressive media on the planet are placing immense amounts of stress on sealing elements. Parker’s FF400-80 compound has been formulated to provide a solution to all of these sealing challenges.
FF400-80 Compound – FFKM Product Features
Temperature range: -40° to 527°F
Best-in-Class low-temperature FFKM
Excellent compression set resistance
RGD resistant per ISO 23936-2 and TOTAL GS EP PVV 142
Sour service H2S resistant per ISO 23936-2
Maintained resilience at high pressures and low temperatures
By switching from gasket seals of PTFE to custom gaskets of DuPont™ Kalrez® perfluoroelastomer parts in the sensor head of a process instrument refractometer used by the food, pulp and paper and chemical industries, process instrument manufacturer K-Patents Oy, Vantaa, Finland, was able to dramatically extend instrument service life, increase reliability and safety, and reduce costs for the company and its customers.
Aggressive environment Through permanent in-line fluids immersion, K-Patents’ “PR-01-S” refractometer is exposed to temperatures from –20 ° to +220 °C, pressures from –0,7 to +25 bar, and some 500 process fluids and chemicals, many of which are extremely aggressive. Delicate digital detector circuits and fiber optics in the sensor head are sealed by two gaskets from attack by aggressive fluids. Because of inherent inelasticity, the original PTFE gaskets could not withstand the dynamic temperature fluctuations of many food, pulp and paper and chemical manufacturing processes, creating a leak path allowing process media to enter and damage the device. As a result, costly replacement of the PTFE seal became necessary approximately every 6–12 months.
Semiconductor FFKM Offers Low Particle Generation AND Extreme Etch Resistance
In the world of semiconductor manufacturing, performance requirements are driving circuit sizes smaller and smaller, causing increased sensitivity to wafer defects. In parallel, the number of manufacturing steps has also increased driving a need for improved tool utilization and leaving more opportunity for these defects to be introduced. Identifying and eliminating the sources of defects is a tedious but necessary process to improve wafer yield.
What impact does seal contamination make?
One very distinct source of defects are the seals within a fab’s tool. Plasmas involved in both deposition, etch and cleaning processes utilize aggressive chemistries that put even high-functioning perfluorinated sealing compounds to the test. Much room for improvement has been left in this industry with many seal materials still posing significant threats to defectivity or downtime despite being designed for low particle generation or etch resistance.
How can Parker ULTRA™ change the industry?
Parker’s UltraTM FF302 Perfluorelastomer has proven success in CVD and etch applications, putting this material at the top of its class. Typically, seal materials for semiconductor applications are optimized for low particulation or extreme etch resistance, however, Ultra FF302 provides both attributes in one material. Laboratory testing shows Ultra FF302 has lower erosion in aggressive plasma chemistries even when compared to today’s leading elastomeric materials (Figure 1 below shows comparison erosion levels of various etch resistant perfluoroelastmers after exposure to O2 plasma).
Below is the third and final section of the white paper, which will discuss the importance of proper seal and groove design.
Proper Seal & Groove Design
Proper seal design is a necessity for elastomer seals to perform reliably over the long term. Many of the instrument applications mentioned above use o-ring seals. The suggested compression for an elastomer o-ring seal to perform properly is typically a minimum of 16%, and a maximum of 30%. However, this range must also take into account the thermal expansion of an elastomer at elevated temperatures as well as any swell due to chemical exposure. Many of the elastomer seals used in instruments are small o-rings, which can create design issues. This is especially true for perfluoroelastomer parts which have a relatively high coefficient of thermal expansion (CTE). Fluoroelastomers have a lower CTE, making seal design easier at elevated temperatures.
Below is the second section of the white paper, diving into applications where the measurement is made in analytical laboratories which employ numerous solvents in a wide range of analyses and test equipment.
The final set of instrumentation is laboratory test equipment. As opposed to the laboratories in chemical plants, which often perform the same routine analyses on plant process streams, general analytical labs employ numerous solvents in a wide range of analyses and test equipment. As such, the ability of seals to resist a breadth of chemicals without degradation or leaching contaminants into a sample is of great importance. Although instrument seals are easily replaced in a laboratory environment, this operation still takes a technician time. It is always easier if the system can be flushed with a cleaning solvent and then be ready to run the next sample versus having to change out an elastomer seal due to incompatibility with a solvent.
FFKMs, also known as perfluoroelastomers, were first developed in the 1960s for applications involving high temperatures and/or aggressive chemicals. Perfluoroelastomers exhibit many properties similar to PTFE (polytetrafluoroethlyene, or Teflon®), and are considered inert in almost all solvents. However, PTFE is a plastic, and when compressed, it will not recover to its original shape. On the other hand, elastomers contain crosslinks, which act as springs to give the material resiliency and the ability to recover after a part has been compressed – this resistance to permanent compression gives the material the ability to maintain a seal over time. (To learn more about perfluoroelastomers, download our Introduction to Perfluoroelastomers White Paper).
The article below was recently published on FlowControlNetwork.com, and discusses how FFKMs are being used in oil & gas exploration, as production companies are increasingly operating in high-pressure, high-temperature (HPHT) downhole conditions.
HOW FFKMS PROTECT COMPONENTS IN ENHANCED OIL RECOVERY OPERATIONS
Companies are increasingly operating in high-pressure, high-temperature downhole conditions.
Improving technologies and methods to increase the recovery of oil from existing reservoirs is a global challenge. In the U.S., oil production at reservoirs can include three phases: primary, secondary and tertiary (or enhanced) recovery. The U.S. Department of Energy (DOE) estimates that primary recovery methods — which rely on the natural pressure of the reservoir or gravity to drive oil into the wellbore, combined with pumps to bring the oil to the surface — typically tap only 10 percent of a reservoir’s oil. Furthermore, secondary efforts to extend a field’s productive life — generally by injecting water or gas to displace oil and drive it to a production wellbore — still only push recovery totals to between 20 and 40 percent of the original oil in place. Clearly, much untapped oil and gas remains in existing wells.
Below is the first section of the white paper, diving into applications where the measurement is made at the process and the results then transmitted to a control system. This section will review the four types of in-line measurement devices, all involving slightly different elastomer sealing applications.
In-Line Process Applications
Flowmeters are used to measure the flow of liquid. In this section we will only consider the measurement of liquid flow in a closed piping system. Several examples of flow measurement devices include: flowmeters, Venturi tubes and orifice plates.
Note that these devices are “in-line” and require isolating the process line to remove and repair, or replace the measurement device. Shutting down a process to remove a device is time consuming, involves loss of production, and may require specific procedures to protect the operators and environment when a line is opened. All of these devices require seals to prevent leakage of the process to the environment and the elastomer seals should last the life of the flowmeter. For aggressive chemicals or high temperature applications, FKM or FFKM seals are an excellent choice. These products offer a long service life and resist deterioration in harsh environments.
The term instrumentation covers a wide variety of applications. In the broadest sense, instrumentation may be considered as any equipment used for measurements. This equipment may be in a process stream and include devices such as flowmeters, pressure gages, and inline probes. Data from these devices are used for process control. In automobiles, sensors are used for a variety of applications including measuring the exhaust stream to “tune” the engine to yield maximum performance. Analytical laboratory instruments such as chromatographs and flame ionization detectors are used to determine the composition of samples. Instruments are used in the medical industry for product analysis as well as analysis of blood and urine samples. Of course this is only a partial list of the many applications involving instruments.
Gallagher Fluid Seals recently made our Fluoroelastomer Basics webinar available on the website.
This webinar will discuss:
Differences between an elastomer and a fluoroelastomer
The important role fluorine plays
Types of fluoroelastomers and their features and benefits
Material performance comparisons
Chemical resistance of fluoroelastomers
Temperature ratings of fluoroelastomers
Considerations when choosing the right fluoroelastomer for your application
What is an Elastomer?
An elastomer is made up of long chain polymers which are connected by crosslinks. Crosslinks are analogous to springs and provide an “elastic” (recovery) nature to the material. The crosslinks are relatively stable, but can break down under extreme temperatures and pressures.
Gallagher Fluid Seals recently added a new white paper to its Resources Page, Perfluoroelastomers for the Semiconductor Industry, written by Russ Schnell. Below is an excerpt from the new white paper discussing the key reasons to choose perfluoroelastomers over fluoroelastomers for semiconductor manufacturing. You can download the white paper in its entirety by clicking on the thumbnail to the right.
Perfluoroelastomers (e.g. Kalrez® parts), often replace fluoroelastomer (e.g. Viton®) in semiconductor applications. However, even though perfluoroelastomers are the highest performance elastomers, there are still subtle differences between products. It is suggested that the elastomer supplier be contacted regarding the optimum product and seal design for specific applications. As mentioned above the key characteristics of perfluoroelastomers include:
Lower offgassing than other elastomers, especially at temperatures above 200°C, which lowers the risk of product contamination.
Better sealing force retention (lower compression set) at temperatures over 200°C, which is critical for longer service.
Best overall chemical resistance of any elastomer family.
Formulations with extremely low particle generation in aggressive process environments.
Generally higher gas permeation than fluoroelastomers.
Higher coefficient of thermal expansion when compared to fluoroelastomers. Proper seal design will account for this and optimize performance.