Case study

Industry: Oil & Gas, LNG

ISSUE

LNG is gaining greater notice for decarbonization efforts

LNG (Liquefied natural gas) is expected to have an important role in reducing the carbon footprint in the next few decades. Natural gas emits significantly lower amount of CO₂ than coal, so switching fuel from coal to natural gas is an available solution. An example of this transition can be seen in power generation.

System-wide LNG carbon emissions are high

A series of LNG plants were built around the world in the 1960s and 1970s. Many of these plants, especially larger ones (1 MTPA and above), use gas turbines for the refrigeration compressors in the liquefaction process. While LNG is a more cleaner energy alternative, it can still create emissions from fuel gas combustion, flaring and venting, fugitive emissions and plant upsets. This creates multiple sources of greenhouse gas emissions in the LNG production chain.

SOLUTION

KEY POINTS TO THE SOLUTION

  • Hybrid combined cycle, which recovers heat from the natural gas liquefaction process, improves the overall thermal efficiency of the LNG plant
  • Combined cycle plant can be used as a clean energy source for liquefaction facilities and other LNG plants
  • Two-shaft H-100 gas turbine, which does not flare during start-up, reduces CO₂ and methane emissions

Waste heat recovery from H-100 gas turbine drives steam turbine and compressor to improve thermal efficiency

Implementation of a hybrid combined cycle that reuses waste heat in the liquefaction train enables recovery of an estimated 50% of the H-100 gas turbine’s output, helping to reduce CO₂ emissions by improving the overall thermal efficiency of the LNG plant. An estimated 50% of the H-100’s gas turbine power can be recovered by implementing a heat recovery system.

The below illustration shows one example of how the recovery and reuse of waste heat in the Hybrid Combined Cycle solution significantly improves the overall thermal efficiency of the entire LNG complex.

Figure of GTCC LNG liquefaction Unit with Separate Power Block
Figure of GTCC LNG liquefaction Unit with Separate Power Block

Cutting carbon emissions by using a power source for motor-driven liquefaction facilities

Standard combined cycle plants can be used as a power source for motor-driven liquefaction facilities. The H-100 gas turbine's productivity and outstanding thermal efficiency make it ideal for combined cycle applications. Overall plant efficiency is greater than 50%, CO₂ emissions to be minimized through power generation.

Figure of Motor Drive LNG Liquefaction unit with Power Block
Figure of Motor Drive LNG Liquefaction unit with Power Block

Dual-shaft gas turbine reduces CO₂ emissions and provides flexibility in operations

Single-shaft gas turbines flare when restarting, but this dual-shaft gas turbine starts without flaring, which is effective in reducing CO₂ emissions. The option of start-up under full settle-out pressure also reduces the possibility of shutdown and enables a quick restart. The H-100 gas turbine has a dual-shaft design. It offers a wide range of/ operating speeds and can respond easily to variations in demand and process conditions.

H-100 Gas Turbine
H-100 Gas Turbine

EXPECTED OUTCOME

Implementing a combined system for waste heat recovery in both the power block and the liquefaction plant enables recovery of an estimated 50% of the H-100's gas turbine power. This increases energy efficiency, contributing to reductions in CO₂ emissions.

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Solution

LNG Solution

“Mitsubishi Heavy Industries (MHI)’ LNG Solution” combines the H-100 gas turbine, one of the world's largest and most efficient dual-shaft gas turbines, with advanced compressor technology to maximize the availability of LNG plants. Our highly efficient equipment for LNG plants can lead to a reduced environmental impact.
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