Everything you should know about storing liquefied natural ...

06 May.,2024

 

Everything you should know about storing liquefied natural ...

Liquified natural gas is projected to become a key source of energy in the coming decades. Propelled by its undeniable advantages (it’s the cleanest fossil fuel, abundant and complements renewable energy sources), LNG is redefining the market as it helps provide energy during demand peaks for a global scenario. 

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Find out what LNG gas is exactly, what uses does this liquified gas present, and what type of LNG tank is the best to store it. 

What is LNG?

Liquefied natural gas (also known as LNG) is natural gas cooled to a liquid state for the purpose of easier storage and transportation

When natural gas reaches about -260° Fahrenheit, through a liquefaction process using cryogenic heat exchangers, it becomes 600 times smaller than natural gas. This facilitates its management and has become its main advantage.

While its liquefaction process was developed in the 19th century, it’s today’s uses of liquefied natural gas that have boosted this element. Thanks to this process, it’s easier to transport LNG through long distances (for instance, from the U.S.A to South Korea) without using gas pipelines, which are not feasible in such cases. 

Demand for LNG has grown over the past years and is expected to continue growing. For instance, U.S. exports of liquefied natural gas continued to grow in the first six months of 2021, at an average that marks an increase of 42%, or 2.8 Bcf/d, compared with the same period in 2020 (following figures by the U.S. Department of Energy’s LNG Monthly).

The main advantages of liquefied natural gas include:

  • Vast resources at a global scale compared to other fossil fuels 
  • The capacity to easily distribute and store it, facilitating having access to it whenever patterns of demand shift.
  • A greener option compared to other fossil fuels, generating cleaner burning than other alternatives. 

Main uses of liquefied natural gas

The main use of liquified natural gas consists of its power as an energy supply. 

energy supply for the following scenarios: 

  • Domestic heating. Liquefied natural gas has become the right answer for peak consumer demands above normal parameters. 
  • The industrial sector uses LNG as fuel for manufacturing diverse items such as electronic devices, fabrics, pharmaceutical products or plastics, among many others. 
  • The transportation sector is beginning to consider LNG as an alternative to petrol.

Storing liquefied natural gas

LNG is a clear and non-corrosive liquid which weighs less than water and is made up of at least 85% methane. It presents several characteristics that must be taken into account when looking for storage alternatives.

Different containers and its characteristics

In order to store it, the right LNG tank is needed, using cryogenic technology to guarantee its optimal and safe storage until LNG is needed. 

These systems usually include above-ground, low-pressure tanks (less than 10 kilopascals), with double walls for enhanced protection and a vacuum that provides thermal insulation and thus maintains the cold temperatures needed. All in all, small amounts of heat enter the system and must be safely removed periodically.

Typically, an LNG tank can have a capacity ranging from 1,000 to 30,000 m³. The bigger tanks present a cylindrical shape with a domed roof, while smaller versions may be stored in both horizontal or vertical pressure vessels, where pressure may range from less than 50 to over 1,700 kPa (7.3–246.6 psi).

Today, an additional high-nickel steel wall or an outer tank made of concrete are often added to provide extra containment. 

Cryospain’s role

Cryospain provides the expertise and technical knowledge to design and implement flat bottom cryogenic tanks for LNG storage

We design our gas storage tanks with double-wall steel structures using high tech insulating materials (cellular glass, expanded perlite, rockwool, etc.).

All the cryogenic storage equipment we produce complies with the most recognized quality and safety certificates on an international level. Our standards include:

  • Mechanical and seismic design: API620, API650, ASME and EN14620, EN14015, EUROCODE
  •  External access: EN ISO14122-1/3 and OSHA 1910.23/24
  • Other regulations including EIGA/CGA/127/13/E and NFPA 59A

Regarding liquefied natural gas, a recent success story in Santa Cruz de la Sierra, (Bolivia) highlights our role as trusted partners. 

This project was both extremely challenging on many levels and hugely gratifying in terms of the benefits it has brought to the area.

This Flat-Bottom Cryogenic Tank is for the storage of Liquid Natural Gas (LNG). This type of installation is known as a “virtual pipeline”. It consists of liquefying natural gas for liquid distribution in areas where it is difficult to install a pipeline network.

The main issue that made our task more daunting was the location itself: deep in the jungle, high in the mountains, far from any urban centres and difficult to access. It was also challenging to find qualified workers in the area. Added to that was the task of building a base camp in the jungle, where heat and rain were constant obstacles.

Transport was also a huge logistical challenge. Parts could not be sent gradually so over 25 containers from all over Spain had to be put on one ship. Not only that, Bolivia has no port, meaning two customs processes, one in Bolivia, but prior to that another upon entry into neighbouring Chile. Getting the trucks to the site wasn’t easy either, given the nature of the terrain.

The project was a success, however, both for our clients and for the environment, allowing access to natural gas to many citizens who have opted to make the switch from heavy hydrocarbons (fuel oil, diesel) to natural gas.

All in all, a challenging project that became a success that benefited both our satisfied customer as well as the local environment.

Want to learn more about LNG and its storage possibilities? Discover our Reference list for cryogenic tanks.

How to make maintenance facilities CNG compliant

Making the switch to compressed natural gas (CNG) as a fueling source can be an easy decision once you crunch the numbers and see the possible savings. You may have already decided to take advantage of those savings by converting your fleet to CNG.

You conducted a feasibility study, calculated your ROI and even applied for federal and state funding to help with the conversion. Now you just have to commission the design for the station and build, right? Wrong. There’s more to it than you think.

In your cost-benefit analysis you probably included the cost of the fueling station and applicable components, and even the cost of the vehicle conversions or new CNG vehicles, depending on what makes sense for your fleet. But what about storing and/or maintaining your new or retrofitted CNG vehicles? Did you know that because of the gaseous state of CNG and its tendency to rise that your maintenance and storage facilities need to be compliant with the applicable codes and regulations?

For more information, please visit LPG Storage Tank manufacturer.

If you get too far into your CNG conversion before considering and accommodating these issues, your project could be delayed, come to a complete halt or even crash and burn. Enlisting a trusted advisor, most likely a design or consulting firm with CNG conversion experience who is familiar with the requirements, codes and regulations surrounding CNG, can help you to achieve a seamless conversion.

WHY CNG?

CNG as an alternative fuel to diesel or gasoline makes economic sense. Making the switch to CNG improves your bottom line, a benefit that a variety of fleets can enjoy. Whether you are a private or public fleet, regional delivery fleet, municipality, school district, taxi fleet or airport, the savings are universal.

You can save an average of 30 to 50 percent on fueling and associated vehicle and maintenance costs. CNG is clean, green, affordable, abundant and most importantly, American. Major regional and even national fleets that have already made the decision to switch include Frito-Lay, Pepsi, UPS, Smith’s Dairy, Dr. Pepper/Snapple and Waste Management, to name a few.

THE WRONG PERCEPTIONS

Most individuals involved in CNG conversions for their fleets tend to think it’s all about the vehicles and station. While those are two major components, there is a third, more "incognito" factor that tends to get overlooked: the maintenance/storage facility. This is one of the major operational components for fleets that need to be upgraded in order to store and perform even light maintenance on CNG vehicles.

There are a lot of players involved in CNG conversions and some of them just want to make money. It is easy to get caught up with manufacturers and salesmen directing you “to do this” and “buy that.” Some of them play on the ignorance and fear of people involved in their fleet’s conversion in order to sell products.

Moreover, there are a lot of over compliance rumors out there, and companies are capitalizing on the misinformation.

Jeff Gicewicz, vice president of corporate holdings for Try-it Distributing, a beverage distributor in Western New York, openly admitted that he didn’t have all of the answers when he pitched the conversion project to his boss. “Plain and simple, there is more to it than I anticipated,” Gicewicz said. “But you don’t know what you don’t know, right?”

Conversions to bring maintenance facilities up to code can be costly and complicated. This is not something most fleets are equipped to handle themselves. Choosing the right trusted advisor can help you through it while minimizing the cost of mistakes or rework, and ensuring a safe working atmosphere.

THINGS YOU NEED TO CONSIDER

Facilities where CNG vehicles are stored or maintained follow a different set of rules because of the chemistry of CNG. Because CNG is a gas, it rises and collects in pockets in the ceiling. Therefore, any items that fall within 18" of the ceiling (for example lighting fixtures or fans) must be Class 1 Division 2.

Class 1 Division 2 references an area where ignitable concentrations of flammable gases, vapors or liquids are present within the atmosphere under abnormal operating conditions. As a result, any equipment that resides in that area must be classified in order to operate under such conditions.

On the other side of that, diesel and gasoline is heavier than air and, therefore, pools on the ground and fumes/liquid seep into the floor and pits. In facilities where maintenance or storage occurs on diesel- or gasoline-powered vehicles, all equipment that falls within 18” of the floor must be Class 1 Division 2.

This is important to consider because if you are building a new facility and considering switching to CNG in the future, making your new garage CNG compliant from the start is much cheaper than retrofitting it down the road. 

In most cases, if the building being retrofitted already meets today’s codes, the cost to get it compliant with CNG codes is incremental. The problem lies in the fact that there are a lot of facilities being used regularly that do not even meet today’s standards for ventilation. These facilities cost more when being retrofitted due to the need to make them current with today’s requirements before considering CNG code compliance.

THE MANY PATHS TO COMPLIANCE

There are several different ways to become CNG compliant. There is not one correct way, or a one-size-fits-all solution.

For example, when retrofitting your garage you have the option of increasing the number of air changes, operating the ventilation system continuously or installing a bunch of methane detectors in order to detect a leak. You can also make alterations to your facility to eliminate pockets in the ceiling where gas collects, or designate a confined area where maintenance and/or storage of CNG vehicles occur to limit the amount of modifications needed.

In some cases, it may be more cost effective to build a brand new facility altogether.

If you prefer not to upgrade your facility, you can outsource the maintenance and storage of your CNG vehicles. That was the decision Try-it Distributing made when it realized that funding for facility upgrades was non-existent.

“The third part beyond the trucks and the filling station would be the building modifications to support the trucks when inside the building for maintenance,” explained Try-it’s Gicewicz. “Because we are not doing it on-site, that really took that third component off the table for us.

“I fully expected us to have to drop $500,000 to $600,000 into our facility to come up to code. It was nice that that price tag went away.”

Try-it entered into a design-build, own and operate contract with Kenworth Truck Company to service Try-it’s CNG vehicles at the OEM’s facility in Buffalo, NY. Kenworth is making the necessary upgrades to its maintenance facility there in order to service Try-it’s fleet, taking a sizable chunk of change out of Try-it’s project cost altogether. 

Try-it will still be making minor upgrades to a limited part of its facility to accommodate the CNG vehicles that are indoors briefly when being loaded with product.

The type of modifications needed depends on what the maintenance facility is being used for. For example:

  • Storage/Light Maintenance: Requires continuous ventilation or methane detection using methane detectors and then implementation of an approved response, such as increasing ventilation, shutting down electric devices and/or opening doors.
  • Heavy Maintenance: Requires continuous ventilation or methane detection using methane detectors and then implementation of an approved response, such as increasing ventilation to exceed normal ventilation rates, shutting down electric devices and/or opening doors.

WHAT CODES AFFECT CNG?

Your trusted advisor can help to make sense of international, national, state and local codes and their contradictions, and navigate you through the facility retrofit. The major codes that affect maintenance facilities come from the National Fire Protection Association (NFPA). They include:

  • NFPA 30A
    • Relevance: Motor Fuel Dispensing Facilities and Repair Garages.
    • In short: Defines major and minor repair garages, which determines the type of codes that are required to store and/or maintain a CNG vehicle.
  • NFPA 52
    • Relevance: Vehicular Gaseous Fuel Systems.
    • In short: Pertains to the design, construction, installation and operation of containers, pressure vessels, compression equipment, buildings and structures, and associated equipment used for storage and dispensing of CNG as an engine fuel.
  • NFPA 70
    • Relevance: National Electrical Code.
    • In short: Addresses the installation of electrical/communications conductors and equipment, and optical fiber cables in commercial, residential and industrial occupancies. 
  • NFPA 88A
    • Relevance: Standard for Parking Structures.
    • In short: Pertains to the parking and storage of CNG vehicles in open and closed parking structures. It also concerns the storage, handling and dispensing of fuels.
  • Other important codes include:
    • International Fire Code.
    • International Building Code.
    • Federal Regulations, such as the Alternative Fuel Vehicle Acquisition and Fuel Use Requirements. (For more information on federal regulations visit the Department of Energy (DOE) website at www.afdc.energy.gov/fuels/laws.)
    • Mechanical Codes.
    • Energy Codes.
    • Local Codes. (For example, the New York City Fire Code is a major factor in Wendel’s CNG facilities upgrade project with the New York City Transit Authority.)  

WHAT’S THE DEAL WITH THE AHJ?

The Authority Having Jurisdiction (AHJ) enforces the codes in their respective state, county or city/town, depending on who it is. The AHJ can be the local fire department, state fire marshal, insurance company or the like.

Although CNG-powered vehicles have been around since the 1930s, they have just recently begun to take off due to the decoupling of crude oil and natural gas. As a result, a large number of AHJ’s have little experience concerning codes that affect CNG vehicles and facilities where they are stored and maintained.

This process is just as new to them as it is to you and your fleet. Finding a trusted advisor who knows the codes and how they affect the design of your facility will truly help to expedite the process and save you money.   

One issue that has come up when Wendel was serving its clients is the conflicts that exist between codes. For example, the international and national codes do not always agree. The AHJ tends to lean toward the more restrictive end of things, or over-compliance.

The most restrictive code is not always the correct answer and having someone there to debate intelligently on your behalf could save you money.

It is also very important to get the AHJ involved in your project as early on as possible. It is much easier to explain what you are doing and why to the AHJ during the design process, rather than presenting them with a finished design and trying to get them on board. That way all comments and concerns can be addressed early on, keeping your project on track.

One way Wendel proactively tackles potential conflict is by employing a process where all team members, including stakeholders and the AHJ, fully immerse themselves into the design by way of several regimented Charrettes and meetings over a two- to three-day period.

One of our recent CNG fueling station/building modification projects in St. Cloud, Minn., got off to a great start as a result of this process, with all stakeholders bought in on the design and the AJH in agreement concerning applicable codes and regulations.

THINGS YOU CAN DO

If you are on the cusp, knee-deep in it or just toying with the idea of upgrading your maintenance facility, there are a few things you can - and should - do:

  1. Do your research. Attend seminars and seek out advice from fleets that have already converted or are in the process. Educate yourself on who the key players are in your region.
  2. “Align yourself with quality people within the industry,” cautioned Gicewicz of Try-it. “I did a lot of research on my own, but we aligned ourselves with the team that seemed to have the most knowledge about this, and that was Wendel’s team.”
  3. Seek out a trusted advisor who will work with you and on your behalf. Choose a firm that is experienced, understands the codes and regulations, and has completed projects of similar scope.

Code review and design approach to the storage and maintenance facility may be the determining factor if CNG is economically feasible for your fleet. This is why an experienced trusted advisor is critically important when deciding on converting.

As someone who is leading the charge and at the heart of Try-it’s conversion, Gicewicz wanted to stress that their decision to switch involved more than the savings on fuel costs.

“We really like to push the fact that it [converting to CNG] lessens our dependence on foreign oil and all of the troubles and heartaches that come with that,” he said. “Not all those companies have our best interests in mind, or our troops’ best interests in mind. That’s definitely a priority for us to get that word out.”

If you are not sure if CNG is a possibility for you, we can conduct a quick, free analysis that estimates possible savings and even a payback period. See Wendel’s website, www.wendelcompanies.com, for contact information.

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