XL-Bore Vacuum-Jacketed Pipe (VJP) can aid aerospace and vehicle-fueling applications
One of the most historic and significant achievements in world history undoubtedly occurred at 10:56 p.m. EDT on July 20, 1969. That’s when American astronaut Neil Armstrong became the first human being to set foot on the moon’s surface, while uttering the immortal words: “That’s one small step for man, one giant leap for mankind.”
In the ensuing decades, men and women have continued to push the envelope of space exploration, from launching unmanned probes and satellites to Venus, Mars and Jupiter to building massive Space Stations that could support human life for months. While the U.S. governmental agency NASA was the driving force for most of space exploration’s history in North America, in recent years, privately owned companies have taken a more active role in developing and providing the spacecraft, launch services and satellite technologies that propagate humankind’s continued presence in space.
A common denominator in many of the excursions into outer space — whether federally or privately funded — is rockets fueled by cryogenic liquids that create enough thrust to break through the Earth’s atmosphere. Those liquids include liquid hydrogen (LH2), liquefied natural gas (LNG), liquid oxygen (LOX) and methane, all of which must be safely maintained at extremely cold temperatures that can be as low as -425ºF (-254ºC).
Coincidentally, it was in 1970, a few short months after Armstrong’s historic stroll, that John Bockris, a University of Pennsylvania chemistry professor, during a presentation at the General Motors Technical Center, coined the term “Hydrogen Economy,” which he viewed as an economy in which the use of hydrogen would address growing concerns about fossil-fuel depletion and environmental pollution. Bockris’ premise received a boost when a technical report by Lawrence W. Jones, a physics professor at the University of Michigan, echoed Bockris’ rationale behind the creation of a Hydrogen Economy while adding that hydrogen could be used to overcome some of the negative effects of using hydrocarbon-based fuels, such as excessive greenhouse-gas emissions.
Today, hydrogen functions as an environmentally sensitive feedstock in the production of a wide range of products, while also being used to power an array of industrial equipment, all with lower emission levels than those of traditional fossil fuels. The growth in the Hydrogen Economy is concurrently buttressed by a maturing infrastructure that encourages the utilization of hydrogen as a renewable energy source for heating homes, schools, hospitals and businesses, facilitating manufacturing, powering vehicles, energy storage and the long-distance transport of energy.
This puts the space-exploration business and the Hydrogen Economy on parallel paths as operators within those realms look to maximize their potential. It also means that ensuring safety within space-launch and hydrogen-based applications remains a front-of-mind task buoyed by the knowledge that the diffusivity, wide flammability range and ultra-low temperatures that are characteristic of cryogenic liquids require specialized product-handling technologies that can not only ensure safe operation but also their reliable and economical production, storage, distribution and consumption.
The Challenge
Handling and transporting cryogenic liquids like LNG and LH2 requires plenty of give and take. As mentioned, they must be kept at extremely cold temperatures lest they are allowed to revert to their natural gaseous state, which can result in huge ambient losses in volume or catastrophic consequences if the flammable gas is concentrated in a way that it can ignite.
At the same time, the liquid volume of LNG, for example, is 600 times smaller than its volume when it is in a gaseous state. Therefore, liquefying natural gas makes it much easier and more efficient to transport with trucks capable of carrying the load to places off-grid if the LNG were shipped in its natural gaseous state.
Therefore, the main challenge in handling and transporting cryogenic liquids is finding and deploying equipment and systems that are able to help ensure that cryogenic substances maintain their liquid state with minimal risk of reverting to their natural gaseous form.
The second challenge concerns volume. It’s not surprising that the amount of LNG, methane or LOX needed to lift a rocket from the launchpad and into space is enormous. Similarly, as the use of LH2 as a motor fuel has grown, its users have determined that it can be most efficiently consumed when used to power long-haul vehicles such as transport trucks, ships, barges and planes.
So, the main task becomes creating a distribution system that possesses the capability to keep cryogenic liquids in their liquid state while simultaneously being able to deliver large volumes of the fuels where they need to be and when they need to be there.
Traditionally, a specific type of piping has been used to accomplish this task, namely a “pipe within a pipe” style that has an inner pipe with a typical diameter of 1/2” to 6” with that pipe surrounded by an outer pipe with a diameter of 2” to 8” — creating a 1/2” x 2” or 6” x 8” configuration. The area between the pipes — called the “annular” space — is traditionally filled with a substance, most commonly foam, that acts as insulation for the inner pipe, which helps the transported cryogenic liquid maintain its proper temperature.
Foam-insulated piping has proven to be less effective in normal 1/2” x 2” to 6” x 8” configurations and applications. Specifically, when used in what are called large-bore and XL-bore sizes with pipe diameters from 12” x 16” up to 24” x 28” — the sizes that are needed to fuel rockets or supply fuel depots for long-haul vehicles — vacuum-insulated piping provides superior thermal efficiency over conventional foam-insulated piping.
Maintaining thermal efficiency is a critical consideration since any decrease in a foam-insulated piping system’s level of thermal efficiency — typically in the form of heat leaks — can compromise any cryogenic liquid’s extremely cold temperature. This can result in harmful performance issues that can negatively affect the overall cryogenic operation. So, when considering the type of insulated piping to deploy in a cryogenic-handling system, keep in mind that VJP can be up to 40 times more effective in reducing heat leaks than foam-insulated piping.
The challenge then becomes what type of piping can be developed and used to defeat the shortcomings of foam-insulated piping in high-volume cryogenic-liquid handling and transport activities?
The Solution
Since 1969, ACME Cryogenics, Allentown, PA, a product brand of OPW Clean Energy Solutions, has been a leading manufacturer of cryogenic gas equipment and systems. One of its major innovations is vacuum-jacketed piping (VJP) systems, equipment and components that can be a safe, reliable and cost-effective method of handling and transferring the full array of cryogenic liquids, from LNG and LH2 to carbon dioxide (CO2) and helium.
Similar to foam-insulated piping, VJP is essentially two pipes in one, with both constructed of stainless steel: an inner pipe that carries the cryogenic liquid and an outer pipe that supports and seals the annular space between the pipes. In the case of VJP, the inner pipe is wrapped with multi-layer insulation (MLI) — also known as “superinsulation” — that is composed of thin sheets of thermal insulation made of a plastic or fiber material that is coated with a metallic material, usually aluminum foil, that blocks radiative heat transfer.
The inner pipe is suspended inside the outer pipe by a series of non-conductive supports while, in some installations, internal or external expansion joints can be used to compensate for the occurrence of any thermal contraction of the inner pipe. During construction, the annular space between the inner and outer pipe is completely evacuated to prevent convective heat transfer. Then, the vacuum space is factory-sealed, forming a “static vacuum.” Finally, chemical “getters” are inserted into the vacuum space, where they remove any residual gas; this allows the VJP to operate maintenance-free for 20 or more years.
Because of its proven success in building VJP systems and equipment, ACME has a number of customers in the space-exploration market. Recently, one of these customers asked if the company had the capability to produce VJP in 16” x 18” or 20” x 24” sizes. While proficient in VJP systems up to 12” x 16”, ACME had never manufactured VJP in XL-bore sizes, but did not shy away from the challenge and set about satisfying the customer’s request.
The result is the company’s first-ever 16” x 18” and 20” x 24” XL-bore VJP piping systems, which are being built in 40-foot “spools,” also called “sticks” or lengths. Piping this big needs to be handled by cranes and other special equipment, but if 15 40-foot spools can be loaded onto a truck and 10 trucks can caravan to the job site, that’s 6,000 feet of VJP ready for installation.
Like all other ACME VJP, these XL sizes are engineered to minimize heat leaks, enhance operational efficiency and reduce costs. With their dual stainless-steel pipe design, they offer superior insulation that surpasses the capabilities of foam-insulated pipe while ensuring optimal thermal performance.
The benefits to the user of XL-bore VJP systems are:
- Higher flow rates for faster liquid transfer
- Enhanced cryogenic-cooling efficiency
- Minimized heat leaks for improved operational efficiency
- Superior performance when compared to traditional insulation methods
- Full customizability to meet the needs of specific cryogenic-liquid handling and transfer applications
- Ability to handle a wide spectrum of cryogenic liquids, including LNG, LH2, LOX, liquid argon (LAR), liquid nitrogen (LIN), CO2 and helium
The overriding benefit of the XL-bore VJP is that it is able to maintain the integrity of the user’s cryogenic-liquid handling processes, with all sizes of ACME VJP designed and manufactured to meet the highest industry standards for safety, reliability and cost-effective performance. The result is substantial savings in terms of lost-gas prevention, reduced maintenance costs and exceptional return on investment over the life of the system.
Conclusion
The ultimate goals of space-exploration companies — viable colonies on the moon, Mars, Venus, “to infinity and beyond” — can only be realized if the methods used to reach space are safe and efficient. At the same time, back on Mother Earth, similar future-focused companies are looking for ways to power vehicles, homes, factories and hospitals in the safest and most environmentally sensitive way. Serving both of these masters are piping systems that are significant links in the cryogenic-liquid supply chain. When these extremely cold liquids are needed in high volumes, the task becomes creating a piping system that can meet all volumetric needs while having the ability to maintain the extremely cold temperatures necessary for effective cryogenic-liquid transfer. The new XL-Bore Vacuum-Jacketed Piping from ACME Cryogenics can play a leading role in optimizing all types of high-volume cryogenic-liquid-handling applications.
About The Author:
Bennett Allred is the Director, Technical Sales and Installation Services for ACME Cryogenics and OPW Clean Energy Solutions and can be reached at bennett.allred@acmecryo.com. OPW Clean Energy Solutions was formed in December 2021 when OPW acquired both ACME Cryogenics and RegO® Products. Since then, the company has continued to expand its reach as a supplier of clean-energy fluid-handling equipment and systems, most notably with the acquisitions in 2024 of Demaco, Marshall Excelsior Company (MEC) and SPS Cryogenics/Special Gas Systems (SPS-SGS). ACME is a leading provider of mission-critical cryogenics products and services that facilitate the production, storage and distribution of cryogenics liquids and gases. RegO is a leading provider of highly engineered flow-control solutions for the cryogenic and liquified-gas end markets. Demaco specializes in the development of vacuum-insulated piping solutions for the cryogenics industry. MEC and its subsidiaries CPC Cryolab, BASE Engineering, Inc., and Xanik develop and supply mission-critical flow-control products and solutions for the LNG, propane and anhydrous ammonia (NH3) markets. SPS-SGS is a manufacturer of vacuum-insulated pipeline systems for use in the handling of a wide array of industrial gases. Together, they are taking OPW beyond conventional fueling solutions and helping define what’s next for alternative energy markets. For more information on OPW Clean Energy Solutions, please visit opwces.com.