LNG plants - small scale liquefaction technology

REVERSED BRAYTON CYCLE – THE RELIABLE SOLUTION FOR SMALL SCALE LIQUEFACTION

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: ~ 0.38 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

    Applications

    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.

    Kollsnes
    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.

     

    Methane Number

    Wärtsilä Methane Number Calculator

    We have developed this tool for ship owners and operators to calculate the Methane Number of the fuel gas.
    The calculation result indicates whether or not the given gas quality is suitable for use in Wärtsilä dual-fuel engines.

    Methane CH4
    mol%
    EthaneC2H6
    mol%
    PropaneC3H8
    mol%
    Iso-butane (2-Methylpropane)i-C4H10
    mol%
    N-butanen-C4H10
    mol%
    Iso-pentane (2-Methylbutane)i-C5H12
    mol%
    N-pentanen-C5H12
    mol%
    EthyleneC2H4
    mol%
    PropyleneC3H6
    mol%
    Neo-pentane (2,2-Dimethylpropane) neo-C5H12
    mol%
    Mix-hexaneMix C6H14
    mol%
    Mix-heptaneMix C7H16
    mol%
    N-Octanen-C8H18
    mol%
    Carbondioxide C02
    mol%
    CarbonmonoxideC0
    mol%
    HydrogenH2
    mol%
    Nitrogen N2
    mol%
    Hydrogen sulfideH2S
    mol%
    Total mol%
    Wärtsilä Methane number (WMN)
    Propane Knock Index (PKI)
    The calculation tool is owned by Wärtsilä and is made for customer use and is for guidance only. Changes in the tool is reserved at any time.

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