Boiled Off Gas Compressor
Boiled Off Gas Compressor
A Boiled Off Gas Compressor (BOG compressor) plays a vital role in LNG (Liquefied Natural Gas) and cryogenic gas storage systems. Designed to handle low-pressure vapors generated due to heat ingress into cryogenic tanks, these compressors recover and re-compress evaporated gases—commonly referred to as boil-off gas—ensuring product conservation, environmental compliance, and operational efficiency.
What Is a Boiled Off Gas Compressor?
Boil-off gas is the vapor generated when cryogenic liquids like LNG warm up and partially evaporate inside insulated storage tanks. A boiled off gas compressor is engineered to handle these low-density vapors, compressing them to higher pressures for reinjection, re-liquefaction, power generation, or safe flaring.
Features of Boiled Off Gas Compressors
- Oil-Free and Gas-Tight Design
Most modern BOG compressors are oil-free and hermetically sealed to prevent any risk of hydrocarbon contamination. This is particularly critical in LNG and hydrogen storage systems where gas purity and environmental safety are priorities.
- High Efficiency at Low Pressure Ratios
Due to the low suction pressure and high gas volumes, BOG compressors are optimized for high volumetric flow rates with low pressure ratios, ensuring stable operation even under fluctuating load conditions.
- Cryogenic Gas Handling Capability
These compressors are specifically built to process cryogenic gases such as methane, nitrogen, hydrogen, and helium, often with extremely low molecular weights and densities.
- Customizable and Modular Design
Depending on the application, BOG compressors can be tailored as centrifugal compressors, screw compressors, or piston-type compressors, with modular skids for easy integration into LNG trains, floating storage regasification units (FSRUs), or marine LNG systems.
- Reliable Operation in Harsh Environments
Designed for continuous duty cycles, these units are engineered for offshore, onshore, and marine applications, delivering robust performance in challenging temperature and humidity conditions.
Applications of Boiled Off Gas Compressors
- LNG Storage Terminals
Recompress boil-off gas from storage tanks for reinjection into pipelines or liquefaction systems.
- Marine LNG Carriers
Compress and redirect evaporated LNG for use as marine fuel or to maintain tank pressure.
- Floating LNG Units (FLNG, FSRU)
Manage BOG in offshore production and regasification platforms where compact and explosion-proof equipment is essential.
- Hydrogen and Helium Storage
Capture and compress ultra-light gases evaporating from cryogenic tanks to minimize product loss.
- Power Recovery and Flare Minimization
Redirect BOG to gas turbines or engines for energy recovery, or to flare stacks in regulated volumes to reduce emissions.
Why Choose a High-Quality BOG Compressor?
Minimizes LNG losses and enhances system efficiency
Reduces environmental emissions by controlling venting and flaring
Protects storage integrity by maintaining safe tank pressure
Improves energy recovery by reusing otherwise wasted gases
Complies with global standards, including ISO, ASME, and API 617
Industry-Proven Technologies
Manufacturers like Huayan offer industry-leading BOG compressor technologies:
- HuanyanHP BOG Centrifugal Compressor
Specifically built for high-pressure boil-off gas recovery, this centrifugal unit handles large flow rates, is API 617-compliant, and features dry gas seals, magnetic bearings, and integrated control systems.
- HuayanBOG Compression Systems
Huanyan provides custom-engineered BOG systems with options for multi-stage centrifugal and screw compression, offering high efficiency and seamless integration into LNG trains and regasification units.
Custom Engineering and Support
Most BOG compressor systems are offered with:
Turnkey engineering packages
On-site commissioning and training
Remote diagnostics and IoT monitoring
24/7 global support network
