Gas Turbine Regasification with Intercooled Compressor
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Solution Overview
Problem
Existing power station plants face inefficiencies and high costs in vaporizing liquid natural gas (LNG), particularly at large terminals, due to suboptimal utilization of low-temperature cold energy and complex designs with numerous rotating components.
Innovation Solution
A power station plant design incorporating a multistage compressor with intermediate cooling, a combustion chamber, and a turbine, coupled with a nitrogen circuit and water-glycol circuit for efficient heat transfer, utilizing low-temperature cold for air compression and LNG vaporization, and minimizing rotating components for simplicity and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If liquid natural gas is vaporized by means of ambient heat or chemical heat, then vaporization can be achieved, but energy efficiency is low and costs are high
Solution Approach 1:
The invention converts the low-temperature cold energy that would otherwise be wasted during LNG vaporization into a useful resource for intermediate cooling of the compressor. The cold LNG stream cools the compressed air between compression stages, reducing the work required by the compressor and significantly improving overall energy efficiency.
Solution Approach 2:
The invention merges the LNG vaporization process with the gas turbine compression process by integrating the heat transfer device between compressor stages. This combination allows simultaneous vaporization of LNG and cooling of compression air, eliminating the need for separate vaporization equipment and reducing system complexity.
2Power
If a heat transfer device is installed between two compressor stages for intermediate cooling, then compressor power requirement is reduced and efficiency increases, but device complexity and material outlays increase
Solution Approach 1:
The heat transfer device serves multiple functions simultaneously: it acts as an intermediate cooler for the compressor, a vaporizer for the LNG, and a heat exchanger for energy recovery. This multi-functionality reduces the need for separate equipment and minimizes overall device complexity despite the added thermal management capability.
3Loss of energy
If the LNG stream is utilized directly for intermediate cooling of air compression, then maximum cooling is achieved and compressor power requirement is minimized, but safety concerns arise from coupling LNG side to working circuit
Solution Approach 1:
The invention introduces a nitrogen circuit as an intermediary between the LNG stream and the compressor air. The nitrogen acts as a safe mediator that can be cooled by the LNG and then used to cool the compressor air, achieving maximum cooling efficiency while preventing direct contact between LNG and the working circuit, thus eliminating safety concerns.
4Stress or pressure
If air compression occurs to significantly higher pressure for recuperated gas turbine operation, then additional gradient for hot air expander is generated, but power requirement for compressor increases
Solution Approach 1:
The invention applies preliminary cooling to the air during compression by utilizing the cold LNG stream (or nitrogen cooled by LNG) to reduce air temperature between compression stages. This preliminary cooling reduces the specific volume of the air, allowing more effective compression and reducing the total work required to achieve the high outlet pressure needed for the recuperated gas turbine cycle.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design achieves high efficiency, up to 73% plant efficiency, with reduced complexity and costs, and provides safety advantages by leveraging low-temperature cold energy for electric power generation with minimal water usage and reduced material outlays.
Implementation Method 1
a heat transfer device is installed between two compressor stages of the compressor and in the natural gas conduit
Implementation Method 2
a first heat exchanger is installed in the compressor air conduit and in an exhaust gas conduit
Implementation Method 3
a turbine located downstream of the combustion chamber
Implementation Method 4
a multistage compressor with intermediate cooling
Implementation Method 5
the heat transfer device to comprise a nitrogen circuit having a nitrogen conduit in which a third heat exchanger and a fourth heat exchanger are installed
Implementation Method 6
a combustion chamber, a turbine located downstream of the combustion chamber
Data Source
AI summary
A power plant with a multi-stage intercooled compressor, a combustion chamber, a turbine which is arranged downstream of the combustion chamber, a compressor air line which connects the compressor to the combustion chamber, and a first heat exchanger which is connected into the compressor air line and into an exhaust gas line branching off from the turbine. A first compressor air expander is arranged in the compressor air line between the first heat exchanger and the combustion chamber, and the power plant includes a device for regasifying liquid natural gas, having a natural gas line, wherein a heat exchanger device is connected into the natural gas line between two compressor stages of the compressor.