Apparatus and method for producing low-temperature compressed gas or liquefied gas
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Solution Overview
Problem
Existing methods for liquefying nitrogen gas using liquefied natural gas (LNG) face inefficiencies due to fluctuations in LNG supply, high energy requirements for compressing gases to low temperatures, and suboptimal use of LNG cold, leading to energy wastage and reduced production efficiency.
Innovation Solution
A Rankine cycle system is employed, comprising adiabatic compression and expansion devices, heat exchangers for constant-pressure heating and cooling, and multiple compression stages to efficiently transfer cold from LNG to nitrogen gas, reducing energy consumption and optimizing LNG usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If nitrogen gas is compressed by a compressor to a pressure for liquefaction and then heat exchanged with LNG, then nitrogen gas can be liquefied, but a large amount of energy is consumed for compression and the cold of LNG is not efficiently used
Solution Approach 1:
The invention changes the pressure parameter of nitrogen gas during the process. Instead of compressing to high pressure before heat exchange, the system first performs heat exchange at low pressure to cool the nitrogen, then compresses the cooled gas. This parameter sequencing reduces the energy required for compression while efficiently utilizing LNG cold for liquefaction.
Solution Approach 2:
The invention applies preliminary cooling action before compression. By first cooling the nitrogen gas through heat exchange with LNG at low pressure, the gas temperature is reduced beforehand. This preliminary action reduces the work required for subsequent compression and maximizes the utilization of LNG cold for achieving liquefaction.
2Productivity
If the amount of LNG supplied increases, then more cold is available, but the existing apparatus cannot efficiently utilize the additional cold, leading to wasted opportunities for increased production
Solution Approach 1:
The invention introduces dynamic adaptability to match LNG supply conditions. The system can adjust its operation based on the amount of LNG supplied, allowing increased production when LNG supply is abundant. This dynamic capability enables the apparatus to fully utilize variable LNG cold resources without wasting opportunities for increased productivity.
Solution Approach 2:
The invention creates a multi-functional system that can operate under various LNG supply conditions. The apparatus is designed to handle both limited and abundant LNG scenarios, enabling it to adapt its production level and operational mode to match supply conditions, thereby maximizing productivity across different operational contexts.
3Temperature
If nitrogen gas is cooled by heat exchange with LNG in a liquid state, then liquefaction can occur, but the LNG with large latent heat is not sufficiently utilized
Solution Approach 1:
The invention ensures continuous utilization of LNG cold throughout the process. By maintaining heat exchange between LNG and nitrogen gas in a continuous manner and optimizing the heat transfer conditions, the system fully exploits the latent heat of LNG for cooling and liquefaction, minimizing wasted energy and maximizing the useful action of the cold source.
Solution Approach 2:
The invention strategically utilizes the phase transition of LNG (liquid state heat exchange) to achieve nitrogen liquefaction. By optimizing the heat exchange process during LNG's liquid phase, the system maximizes the utilization of LNG's latent heat for cooling nitrogen gas to its liquefaction temperature, thereby reducing energy loss and improving overall efficiency.
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
The system significantly reduces energy needed for producing low-temperature compressed fluids and liquefied nitrogen, achieving improved energy efficiency by efficiently utilizing LNG cold and maintaining stable fluid production despite supply fluctuations.
Implementation Method 1
heat exchangers for constant-pressure heating and cooling
Implementation Method 2
adiabatic compression and expansion devices
Implementation Method 3
adiabatic compression and expansion devices
Implementation Method 4
adiabatic compression and expansion devices
Implementation Method 5
vaporize the LNG by raising the temperature
Implementation Method 6
the LNG that is subject to heat exchange with this nitrogen is still in a liquid state having a large latent heat
Data Source
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AI summary
An apparatus and a method for cooling and compressing a fluid to produce a low- temperature compressed fluid that can efficiently use the cold of LNG and can reduce the energy needed, the apparatus using a Rankine cycle system comprising; a first compression device(1), a first heat exchanger (2), an expansion device(3), a second heat exchanger (4), and a first flow passageway for guiding the heat transfer medium from the second heat exchanger to the first compression device; and at least one second compression device(6) that is coupled to the expansion device, wherein, at the second heat exchanger, a low-temperature liquefied natural gas and the heat transfer medium undergo heat transfer, wherein, at the first heat exchanger, a fed material gas and the heat transfer medium undergo heat transfer to produce a low-temperature fluid from the material gas, and wherein, the low-temperature fluid is thereafter compressed at the second compression device to produce a low-temperature compressed fluid.