Compact system and method for the production of liquefied natural gas
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Solution Overview
Problem
Conventional modular LNG production systems face high capital expenditures and large footprints due to large modules requiring extensive structural steel and numerous equipment items, leading to increased construction time and costs, despite aiming to reduce labor costs and improve quality.
Innovation Solution
A modular LNG production facility with a liquefaction train comprising multiple modules for acid gas removal, dehydration, and liquefaction, utilizing a dual mixed refrigerant cycle with a primary closed water cooling loop and integrated pipe-rack system, featuring printed circuit heat exchangers for efficient cooling and reduced equipment weight, and optimizing module design to minimize interconnections and hook-ups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional modular LNG production systems use large modules with extensive structural steel and numerous equipment items, then structural strength and equipment capacity are improved, but capital expenditure and footprint increase
Solution Approach 1:
The patent changes the physical state of the natural gas from gaseous to liquid through cryogenic cooling, achieving compact storage and transport. This phase change enables smaller facility footprint and reduced capital expenditure while maintaining processing capacity
Solution Approach 2:
The liquefaction process is divided into multiple temperature stages using cascade heat exchangers, with each stage handling a specific temperature range. This segmentation allows optimized equipment selection and reduced overall system complexity, lowering capital costs
2Quantity of substance
If conventional modular systems use large modules, then equipment capacity is improved, but construction time increases
Solution Approach 1:
The facility is designed as modular units that can be pre-assembled and then quickly deployed. The segmented approach allows parallel construction of multiple modules, significantly reducing total construction time while maintaining overall equipment capacity
Solution Approach 2:
Modular components are designed and prepared in advance with standardized connections and pre-installed equipment. This preliminary preparation enables rapid on-site assembly, reducing construction time without compromising equipment capacity
3Temperature
If refrigerants are cycled through compression and expansion to cool natural gas, then liquefaction is achieved, but energy consumption increases
Solution Approach 1:
The patent recovers waste heat from the refrigerant compression and expansion processes and uses it to pre-cool the incoming natural gas or to generate power. This converts the energy loss into a beneficial resource, reducing overall energy consumption while maintaining cooling efficiency
Solution Approach 2:
Heat that would otherwise be discarded during refrigerant cycling is recovered and reused in the process. The waste heat from compressors and expansion devices is captured and applied to pre-cool feeds or generate electricity, reducing the energy input required for liquefaction
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 solution significantly reduces capital expenditure and footprint while maintaining energy efficiency and greenhouse gas performance, enabling faster construction and lower costs compared to conventional systems, with a modular design that integrates multiple process units within each module and utilizes water cooling for compact and lightweight equipment.
Implementation Method 1
Refrigerants are cycled in one or more refrigeration loops to reduce the temperature of the treated gas to a temperature of around −160° C. to form LNG
Implementation Method 2
This results in warming of the respective refrigerant which must be compressed for recycle to the liquefaction process and subsequent expansion
Implementation Method 3
Compressors used for this duty may be centrifugal compressors driven by gas turbines or electric motors
Implementation Method 4
Liquefaction is achieved using processes which typically involve compression, expansion and cooling
Data Source
AI summary
A facility for the production of liquefied natural gas comprising a liquefaction train. The train comprises a plurality of modules to perform the process steps associated with liquefied natural gas production. The train further comprises a primary cooling loop to cool at least a process stream from each module and a first and a second mixed refrigerants against a first coolant comprising clean water. The primary cooling loop is a closed clean water loop, and the cooling is against an ambient temperature. The train further comprises a first plurality of heat exchangers through which the primary cooling loop extends. The cooling is via heat exchange in at least the first plurality of heat exchangers with respect to the first coolant. More than 50% of the first plurality of heat exchangers are printed circuit heat exchangers, which are adapted to provide at least 80% of the cooling against the ambient temperature.