Cascade ORC Regasification Line for Lower LNG Energy Loss
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Solution Overview
Problem
Conventional regasification technologies for liquefied natural gas (LNG) face inefficiencies, including high energy loss, complex designs, and electrical load imbalances, particularly in systems using Organic Rankine Cycles (ORC) and Submerged Combustion Vaporizers (SCV), which result in excessive energy consumption and environmental impact.
Innovation Solution
Integration of a modified regasification line incorporating two Organic Rankine Cycles (ORC) in cascade, utilizing two different organic fluids, where the condensation heat of one cycle is used to evaporate the second fluid and vaporize LNG, with an energy by-pass circuit that includes heating sections and turbines to optimize thermal and electrical energy production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional regasification technologies (ORV, SCV) are used, then regasification of LNG can be achieved, but high energy loss and excessive energy consumption occur
Solution Approach 1:
The regasification process is divided into multiple stages using different heat sources: first stage uses cold well LNG (-160°C) for pre-heating, second stage uses ORC condensation heat for vaporization, and third stage uses seawater for final heating. This segmentation allows optimal utilization of each heat source's temperature level, minimizing exergy loss and improving overall energy efficiency.
Solution Approach 2:
The invention changes the temperature parameters of heat transfer by matching heat source temperatures with process requirements: cold well LNG at -160°C for low-temperature pre-heating, ORC condensation at approximately -40°C to 0°C for vaporization, and seawater at 5°C to 20°C for final heating. This parameter optimization reduces thermal gradients and improves heat transfer efficiency.
2Use of energy by moving object
If ORC systems are integrated to improve energy efficiency, then electrical and thermal energy production increases, but electrical load imbalance occurs
Solution Approach 1:
The system incorporates dynamic load balancing capabilities where the ORC turbines can be selectively activated or deactivated based on real-time electrical demand. The control system adjusts the number of operating turbines and their power output to match grid requirements, while thermal load is continuously met by the heat exchange network. This dynamic adjustment resolves the contradiction between maximizing energy efficiency and maintaining electrical load balance.
3Ease of manufacture
If SCV technology is used for regasification, then vaporization of LNG is achieved, but complex design and excessive fuel gas consumption occur
Solution Approach 1:
The system uses the cold well LNG itself as the heat source for pre-heating incoming LNG, creating a self-service cooling system. The expanded LNG after pressure reduction serves dual purposes: it cools the incoming liquid and provides refrigeration for the condensation section. This eliminates the need for separate fuel gas consumption and simplifies the overall system design compared to SCV technology.
4Loss of energy
If cold well LNG is used for pre-heating, then energy efficiency improves, but freezing of seawater may occur in heat exchangers
Solution Approach 1:
The heat exchanger system is designed with local quality differentiation: the first heat exchanger uses cold well LNG at -160°C for pre-heating in a controlled environment, while the second heat exchanger uses seawater at 5°C to 20°C for final heating. The ORC condensation heat exchanger operates at intermediate temperatures (-40°C to 0°C) specifically matched to the ORC working fluid properties. This local optimization prevents seawater freezing while maintaining maximum energy efficiency at each stage.
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 approach enhances energy efficiency, reduces energy loss, and allows for flexible operation by balancing electrical and thermal loads, enabling continuous regasification even in challenging conditions, while minimizing environmental impact and simplifying seawater treatment requirements.
Implementation Method 1
a first step of heating the liquefied gas by means of a heat exchange with a first organic fluid (OF1)
Implementation Method 2
a second step of heating the liquefied gas with a second organic fluid (OF2), wherein said first organic fluid (OF1) is subjected to a step of heat exchange (HEAT1) by means of which it acquires thermal energy from the second organic fluid (OF2)
Implementation Method 3
wherein the condensation heat of the cycle of a fluid is used for evaporating a second fluid
Implementation Method 4
the condensation heat of the cycle of a fluid is used for evaporating a second fluid and for vaporizing the liquefied natural gas
Implementation Method 5
Organic Rankine Cycle (ORC) type into a traditional regasification line
Data Source
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AI summary
The object of the present invention is a regasification line for a liquefied gas comprising a first heating section (COND1), a second heating section (COND2), wherein said first heating section (COND1) is part of a first cycle which operates with a first organic fluid (OF1) and said second heating section (COND2) is part of a second cycle which operates with a second organic fluid (OF2), said organic fluids (OF1, OF2) being mutually different, and wherein said first cycle further comprises an evaporator (EVA1) of said first organic fluid (OF1) which operates with said second organic fluid (OF2).