Cryogenic Heat Exchanger Solvent Injection for Deriming Buildup
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Solution Overview
Problem
The accumulation of heavy hydrocarbons, ice, and other solids in cryogenic heat exchangers and associated equipment leads to reduced heat transfer efficiency, pressure drops, and decreased liquefied natural gas (LNG) production due to buildup, which existing systems fail to effectively address.
Innovation Solution
A method and system utilizing a pumping vessel with a mechanical linkage and float mechanism to inject a solvent, such as liquid petroleum gas, into the cryogenic heat exchanger at a variable rate to remove buildup, involving the controlled opening and closing of valves to maintain pressure and engage the float for solvent injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cryogenic heat exchangers operate at lower temperatures to enhance LNG production, then liquefaction efficiency is improved, but buildup of heavy hydrocarbons and ice accumulates on interior surfaces reducing heat transfer
Solution Approach 1:
The system performs preliminary cleaning action by injecting solvent into the heat exchanger before severe buildup occurs, using a timer or temperature differential sensor to trigger periodic solvent injection cycles that prevent accumulation of heavy hydrocarbons and ice on heat exchange surfaces
Solution Approach 2:
A solvent is introduced as an intermediary substance to dissolve and remove the buildup of heavy hydrocarbons and ice on the heat exchanger surfaces, allowing the system to maintain low operating temperatures for high LNG production while periodically clearing accumulated solids that would otherwise reduce heat transfer efficiency
2Productivity
If cryogenic heat exchangers are operated continuously to maximize production, then LNG output increases, but buildup accumulates over time requiring shutdown for maintenance
Solution Approach 1:
The system maintains continuous operation by implementing continuous or periodic solvent injection through the heat exchanger, preventing buildup accumulation that would otherwise require shutdowns, thereby sustaining uninterrupted LNG production while automatically clearing surfaces that become fouled during operation
Solution Approach 2:
The heat exchanger performs self-cleaning by injecting solvent through its own flow paths, using the existing fluid distribution system to deliver cleaning agent to interior surfaces without requiring external disassembly or manual intervention, enabling continuous autonomous operation
3Reliability
If solvent injection rate is increased to improve cleaning effectiveness, then buildup removal is enhanced, but system complexity and control difficulty increase
Solution Approach 1:
The system uses temperature differential sensors or pressure differential measurements across the heat exchanger to monitor buildup conditions and automatically adjusts solvent injection rate accordingly, increasing injection when buildup is detected and reducing or stopping injection when surfaces are clean, eliminating the need for complex manual control systems
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
Effectively removes buildup from cryogenic heat exchangers, enhancing heat transfer efficiency and LNG production by ensuring continuous operation and maintaining pressure within the system.
Implementation Method 1
a moveable float located within the pumping vessel chamber, wherein the moveable float is attached to the pumping vessel chamber by a mechanical linkage
Implementation Method 2
injecting a solvent, such as liquid petroleum gas, into the cryogenic heat exchanger to remove buildup
Data Source
AI summary
The invention relates to a method and apparatus relate for the liquefaction of natural gas. In another aspect, the present invention concerns the deriming the interior surfaces of a cryogenic heat exchanger employed in the liquefaction of natural gas. In another aspect, the present invention concerns the utilization of a pump to derim the interior surfaces of a cryogenic heat exchanger.