Luyi Vehicle-Custom Semi Trailers & Truck Manufacturer Since 2019.
What are LNG & LPG Tank Trailer?
POSTED ON 2025-06-10 BY Shandong LUYI Vehicles
2025-06-10
Whether you need to transport liquefied natural gas (LNG) and liquefied petroleum gas (LPG), or solve the transportation problems of large equipment, you are sure to find solutions at LUYI.
A great deal of effort has been devoted to the research, design and manufacture of tanker product transportation. This chapter discusses LNG and LPG tank trailers in detail.
WHAT IS AN LNG TANK TRAILER?
LNG Tank Semi-trailer is a cryogenic pressure vessel vehicle dedicated to transporting Liquefied Natural Gas (Liquefied natural gas, LNG) and is classified as a hazardous chemicals transportation equipment. Its core function is to safely store and transport LNG at an ultra-low temperature of -162°C, maintaining a liquid state and reducing evaporation losses.
Liquefied natural gas (LNG) cryogenic tank trailers are key transportation tools in LNG logistics. They can operate at ultra-low temperatures (-162°C) to keep natural gas in a liquid state. Unlike traditional tank trucks, liquefied natural gas trailers operate under extreme conditions and require advanced engineering technology to ensure safety and efficiency during transportation.
LIQUEFIED NATURAL GAS TANK STRUCTURES
LNG Tanker Trailer Drawing
Key Challenges in LNG Transport
During transportation, LNG continuously undergoes boiling and gasification due to several factors:
-
Heat Ingress – Despite high-performance vacuum insulation, minimal heat transfer occurs, causing gradual vaporization.
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Dynamic Effects – Sloshing from vehicle movement or rapid refilling accelerates gas release.
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Pressure Fluctuations – Changes in atmospheric pressure (e.g., altitude shifts) impact tank equilibrium.
Engineering Solutions for LNG Tank Trailers
To address these challenges, manufacturers integrate specialized systems:
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Pressure Management – Automated relief valves and vapor recovery units maintain safe internal pressure (typically 0.7–1.0 MPa).
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Boil-Off Gas (BOG) Handling – Excess gas is either reliquefied, combusted as fuel, or safely vented.
Enhanced Insulation – Multi-layer vacuum insulation (e.g., perlite or MLI) minimizes heat leakage, keeping evaporation rates below 0.3% per day.
DIFFERENT FORMS OF HEAT HEATINSULATION
At present, four forms of thermal insulation are used in LNG tank trailer. The four types include:
- Packed heat insulation
- High vacuum heat insulation
- Powder fiber insulation (vacuum)
- High vacuum multi-layer insulation (vacuum)
In this article, we will introduce you to the highest level of insulation materials, namely high vacuum multi-layer insulation materials. High vacuum multi-layer insulation materials are one of the most advanced insulation technologies at present, which can significantly reduce heat conduction and evaporation losses, ensuring the safe and efficient transportation of LNG.
Application advantages:
✅ Ultra-low evaporation rate - reduces vaporization loss during LNG transportation and improves economic efficiency.
✅ Lightweight - thinner than conventional perlite insulation, reducing the self-weight of tankers.
✅ Long life - high material stability, not prone to aging, low maintenance cost.
✅ Environmental friendliness - No dust pollution, compliant with strict emission standards.
✅ Lightweight - thinner than conventional perlite insulation, reducing the self-weight of tankers.
✅ Long life - high material stability, not prone to aging, low maintenance cost.
✅ Environmental friendliness - No dust pollution, compliant with strict emission standards.
High vacuum multi-layer insulation materials are the gold standard for the insulation technology of LNG tankers, especially suitable for long-distance and high-value-added LNG transportation. With technological progress, its cost is expected to decrease, promoting broader market applications
WHAT IS AN LPG TANK TRAILER?
LPG (Liquefied Petroleum Gas) tank trailers are distinct from LNG trailers in both design and application. These specialized pressure vessels are engineered to safely transport a wide range of liquefied gases under varying temperature and pressure conditions.
LPG tank trucks (Liquefied petroleum gas transport vehicles) are pressure vessel vehicles specifically designed for transporting liquefied petroleum gas and are widely used in the distribution of civil gas, industrial fuel and chemical raw materials. Its core function is to safely store and transport propane (C₃H₈), butane (C₄H₁₀) or their mixtures under normal temperature and high pressure conditions.
DESIGN AND STRUCTURE OF LPG TRAILERS
LPG (Liquefied Petroleum Gas) trailers are pressurized tankers designed to transport liquefied gases such as propane, butane, ammonia, and other industrial gases in a safe and efficient manner. Unlike cryogenic LNG trailers, LPG trailers operate at ambient temperatures but under high pressure (typically 1.0–2.2 MPa).
To prevent overpressure, the pressure reducing valve is set at 110% of the maximum pressure it can withstand. The shaft configuration is 3-4 shafts, meeting the legal road requirements.
The anti-corrosion internal coating can be selected as epoxy coating, which is suitable for corrosive chemicals (such as ammonia), and the external coating is also selected as corrosion-resistant coating. In this category, there are also cryogenic transport tankers, which are specifically used for transporting liquid oxygen, liquid nitrogen, liquid hydrogen, liquid argon, liquid carbon dioxide and other media.
These tank trucks are made of steel and have insulation layers and pressure shells on the outside. Such vehicle models must be equipped with safety accessories such as rupture disc devices, emergency shut-off devices, static electricity devices, safety valves, pressure gauges, liquid level gauges and thermometers. Tanker trucks can be exposed or have insulation layers or insulation shells. Most importantly, the design, manufacture, use, transportation, inspection, maintenance and refurbishment of the transport tank trucks all comply with industry standards and traffic management regulations.
LPG TANK TRAILER CATEGORIES
Petroleum gas vehicles can be classified according to their specific uses. According to the different materials being transported, they can be classified as: propane transport trailers, butane transport trailers, propylene and butadiene transport trailers, liquid ammonia transport trailers, dimethyl ether and liquid nitrogen transport trailers, acetal transport trailers, etc.
Four materials are commonly used in the manufacture of liquefied petroleum gas storage tanks, namely Q235-C, 20R, 16MnR and 15MnR. The following table shows the comparison of the yield strength and allowable stress of these four materials.
| MATERIAL | YIELD STRENGTH (MPA) | PERMISSIBLE STRESS (MPA) | COMPARISON |
|---|---|---|---|
| Q235-C | 225 | 125 | The allowable stresses of these two materials are relatively small. Therefore, the thicker the tank wall is, the greater the empty weight is, and thus the smaller the load-bearing capacity is. |
| 20R | 235 | 133 | |
| 16MnR | 345 | 170 | This material has a moderate wall thickness, that is, 10-14mm. It is currently a commonly used material for manufacturing LPG storage tanks. The welding technology is mature and has a high cost performance. |
| 15MnVR | 390 | 177 | The properties of this material are similar to those of 16MnR. However, the price of this kind of material is relatively high. |
LPG TANK TRAILER LOADING PRINCIPLE
The loading process of the liquefied gas storage tank trailer is the transfer process between the liquefied gas storage tank and the liquefied gas transport vehicle. This process involves using a sliding pump to unload the storage tank while filling the transport vehicle. This process is mainly divided into four steps and is described in detail as follows:
1.Before the work begins, pressure balancing needs to be carried out between the two storage tanks to facilitate the transfer of liquefied gas.
2. Start the sliding pump and draw liquefied petroleum gas from the bottom of the storage tank through the delivery pipe, and then deliver the gas through the bottom of the delivery tank.
3. When the transport tank is filled with liquefied gas, the accumulated steam is passively transferred from the top of the transport tank to the top of the storage tank. This ensures that pressure balance is maintained during the transmission process.
4. When the conveying tank is filled with the required volume, the LPG conveying process is completed.
2. Start the sliding pump and draw liquefied petroleum gas from the bottom of the storage tank through the delivery pipe, and then deliver the gas through the bottom of the delivery tank.
3. When the transport tank is filled with liquefied gas, the accumulated steam is passively transferred from the top of the transport tank to the top of the storage tank. This ensures that pressure balance is maintained during the transmission process.
4. When the conveying tank is filled with the required volume, the LPG conveying process is completed.
A comparison between LNG and LPG
| Feature | LPG Trailer | LNG Trailer |
|---|---|---|
| Storage Method | Pressurized (ambient temp.) | Cryogenic (-162°C, low pressure) |
| Tank Material | Carbon steel | Stainless steel / Nickel alloy |
| Insulation | Minimal (unless temp.-sensitive) | High-vacuum multilayer insulation |
| Pressure Rating | 1.0–2.2 MPa | 0.7–1.0 MPa |
| Common Gases | Propane, butane, ammonia, DME | Pure methane (CH₄) |
This article provides a simple guide to help you understand the basics of LPG and LNG tanks. Use this information to identify the tank trailer that is best suited to transporting liquefied gases from one location to another.
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