LNG Plants – Small Scale Liquefaction Technology


Wärtsilä’s larger liquefaction plants are easy to operate, reliable, and fully automated. They represent a low lifecycle cost solution in the small to medium size liquefaction capacity range.

These liquefaction plants are based on the Reversed Brayton nitrogen refrigeration cycle. Nitrogen is the sole refrigeration medium, and is used in a process of compressing and expanding the nitrogen to obtain the required cryogenic temperature.

Wärtsilä provides the basic complete process package, to which can be added civil engineering and construction services. The complete plant can also be supplied as an EPC delivery. Once installed, Wärtsilä further offers Operation & Maintenance agreements that are tailored to the customer's specific needs.

    Technical data

    Main Technical data:

    • Energy consumption: ~ 0.35 kWh/kg LNG
    • Capacities between 60-800 tons/day
    • Based on proprietary reversed Brayton technology
    • Simple process and less equipment needed because the refrigerant (Nitrogen) is always in gas phase
    • Smaller plants designed for unmanned operation
    • Delivery time: 18-22 months.
    Small Scale Liquefaction
    3D model for 400 ton per day plant

    Small scale liquefaction plants open new market opportunities for the development of local or regional gas distribution networks, where gases did not previously exist as an alternative environmentally friendly and competitive energy source. Small scale LNG is also highly interesting as a price competitive and environmentally friendly fuel for ships, trucks and general industry. Cost and energy efficient small scale LNG plants also open possibilities to monetize previously stranded gas sources.

    Gas sources can typically be pipeline gas, well gas or flare gas.

    Such gases need to be cleaned to achieve low contents of water (1 ppm), CO2 (<50 ppm) and H2S (< 4ppm). Gas cleaning systems can also be delivered by Wärtsilä upon request.

    The Kollsnes II plant (below) located near Bergen, Norway features a complete LNG plant scope including a total gas cleaning system.

    The Kollsnes II 240 ton per day plant
    Key benefits

    The benefits of the Brayton Nitrogen Cycle from Wärtsilä include:

    • Low power consumption - reducing OPEX.
    • A nitrogen-only cooling cycle reduces complexity and increases ease of operation.
    • Nitrogen cycle offers high inherent process safety.
    • High availability.
    • Refrigerant (nitrogen) will be produced directly from air on site. No logistics or complex make up system connected to refrigerant handling.
    • Refrigerant always in gaseous phase, no liquid levels to control, and no risk of mal-distribution on heat exchanger headers.
    • Installation is simple and time efficient, as all equipment comes as ready-made modules. No stick building on site.
    • Compact technology – small footprint required.
    • Robust, reliable and simple to operate technology.
    • Capacity control is easy and with fast response – within minutes.
    • Easy start up and shut down of all systems.
    • Simple energy supply, only electric power needed.
    • Smaller plants are designed for unmanned operation.
    • There is no required handling of chemicals.
    • Our design provides a ZERO FLARE solution. During normal operations, hydro-carbon losses will be zero.



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