LNG Re-gasification via Pressure Difference Power Generation
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Solution Overview
Problem
Current natural gas power generation systems face inefficiencies due to energy loss during pressure reduction and re-gasification processes, which can impact both gas turbine and supercritical fluid power generation, and may have adverse environmental effects from seawater use.
Innovation Solution
A combined power generation system that heats natural gas through a pressure difference power generation facility and uses cold energy from liquefied natural gas as a coolant, integrating a gas turbine and supercritical fluid power generation system with waste-heat recovery and heat exchange facilities to enhance efficiency and eliminate external heat sources for re-gasification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If natural gas is burned by a burning system to generate heat for LNG re-gasification, then re-gasification can be achieved, but energy is wasted
Solution Approach 1:
The patent converts the cold energy that would otherwise be wasted during LNG re-gasification into a useful resource by using it to drive a power generation cycle. The cold energy from LNG is used to cool the working fluid in the power generation system, replacing the need for external cooling sources and simultaneously generating electricity.
Solution Approach 2:
The patent merges the LNG re-gasification process with the power generation process into a single integrated system. The heat exchanger serves dual purposes: facilitating heat transfer for re-gasification and enabling the power generation cycle by cooling the working fluid with LNG cold energy.
2Loss of energy
If a pressure reducing valve is used to control the pressure of natural gas, then pressure control is achieved, but energy is lost during decompression
Solution Approach 1:
The patent converts the energy loss during natural gas decompression into useful work by using the pressure difference to drive a turbine. The pressure reducing valve's decompression process is coupled with a turbine that generates electricity, transforming the previously wasted energy into a beneficial output.
Solution Approach 2:
The patent introduces a turbine as an intermediary device between the pressure reducing valve and the natural gas flow. The turbine acts as a mediator that captures the energy from the pressure drop and converts it into rotational motion and electricity, rather than allowing the energy to be dissipated.
3Object-affected harmful factors
If seawater is used for LNG re-gasification, then re-gasification can be performed, but marine ecosystems are adversely impacted
Solution Approach 1:
The patent converts the cold LNG into a beneficial cooling resource for power generation, eliminating the need to use seawater for cooling purposes. The LNG cold energy drives the power generation cycle, replacing seawater as the cooling medium and thereby protecting marine ecosystems.
4Productivity
If natural gas is heated to high temperature for gas turbine, then power generation efficiency is improved, but additional energy input is required
Solution Approach 1:
The patent merges the heating process with the power generation cycle by using the waste heat from the gas turbine exhaust to heat the natural gas. The heat exchanger captures thermal energy that would otherwise be wasted and uses it to preheat the natural gas before it enters the gas turbine, improving overall efficiency without requiring additional external energy input.
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 system improves power generation efficiency by heating natural gas before it enters the gas turbine and utilizes cold energy for re-gasification without external heat, reducing energy waste and environmental impact.
Implementation Method 1
a pressure difference power generation facility for generating electricity by using a pressure change of natural gas
Implementation Method 2
a heating unit configured to heat the natural gas discharged from the pressure difference power generation facility, the heated natural gas being heated to a high temperature
Implementation Method 3
a combustor that mixes the compressed air and the natural gas discharged from the pressure difference power generation facility and burns the resulting fuel-and-gas mixture to produce a flue gas
Implementation Method 4
a turbine provided with turbine blades rotated by the flue gas, and a generator connected to and rotated by the turbine to generate electricity
Implementation Method 5
a waste-heat recovery heat exchange facility configured such that heat exchange occurs between the flue gas produced by the gas turbine power generation facility and the working fluid to be used in the supercritical fluid power generation facility
Implementation Method 6
a supercritical fluid power generation facility for generating electricity by using a supercritical working fluid heated by the flue gas produced by the gas turbine power generation facility
Implementation Method 7
a liquified natural gas (LNG) heat exchange facility in which heat exchange occurs between the working fluid discharged from the supercritical fluid power generation facility and liquefied natural gas so that the working fluid is cooled and the liquid natural gas is heated to be re-gasified into natural gas
Data Source
AI summary
A combined power generation system performing pressure difference power generation includes a pressure difference power generation facility generating electricity by using a pressure change of natural gas; a gas turbine power generation facility including a compressor, a combustor, a turbine, and a generator; and a heating unit to heat the natural gas discharged from the pressure difference power generation facility. A first bypass channel enables the natural gas to bypass the pressure difference power generation facility, and a second bypass channel enables the natural gas to bypass the heating unit. The heated natural gas is heated to a high temperature and then introduced into the combustor of the gas turbine power generation facility. Since the natural gas to be used in the gas turbine power generation facility is preliminarily heated while passing through the preceding power generation facility, the generation efficiency of the gas turbine power generation efficiency is improved.