Cryogenic Deriming Solvent Injection Without High-Pressure Metering Pumps
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Solution Overview
Problem
The accumulation of heavy hydrocarbons, wax, or ice on the interior surfaces of cryogenic heat exchangers and other equipment reduces heat transfer efficiency, pressure, and flow rates, necessitating an effective method for removal without the limitations of motor-driven metering pumps in high-pressure applications.
Innovation Solution
A method and apparatus utilizing a pumping vessel with controlled valves to inject a solvent, utilizing process gas for re-pressurization and pressure regulation, allowing for continuous monitoring and automated operation to deliver the solvent into cryogenic equipment, ensuring efficient removal of buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If motor-driven metering pumps are used to inject solvent into high-pressure cryogenic equipment, then solvent injection capability is provided, but the system becomes complex and reliability decreases due to limitations in high-pressure service
Solution Approach 1:
The patent replaces motor-driven metering pumps with a gas-pressure-driven injection system. Process gas from the cryogenic equipment itself is used to pressurize and deliver the solvent through a manifold system, eliminating the need for external motor-driven pumps that have reliability issues in high-pressure cryogenic service.
Solution Approach 2:
The system uses the process gas already present in the cryogenic equipment to provide the pressure needed for solvent injection. The equipment's own operating conditions are utilized to drive the deriming process, eliminating the need for external power sources and complex pump systems.
2Manufacturing precision
If solvent is injected into cryogenic equipment to remove buildup, then heat transfer efficiency is improved, but pressure drop increases during the injection process
Solution Approach 1:
The patent divides the solvent injection into multiple sequences through a manifold system with multiple injection points. Instead of a single high-pressure injection event, the solvent is delivered sequentially through different sections of the heat exchanger, distributing the pressure impact and maintaining more stable operating conditions.
Solution Approach 2:
The solvent injection is performed in periodic sequences rather than continuously. The system injects solvent in controlled bursts, allows it to act, then pauses before the next injection sequence. This periodic action prevents sustained high pressure drops while still achieving effective buildup removal.
3Device complexity
If manual deriming procedures are used, then system complexity is reduced, but productivity decreases due to frequent shutdowns and manual intervention
Solution Approach 1:
The system is designed to be self-regulating using the existing process conditions. Process gas automatically pressurizes the solvent delivery system, and the solvent injection sequences are controlled by pressure differential and timing mechanisms that require no external power or complex control systems, maintaining simplicity while enabling continuous operation.
Solution Approach 2:
The patent enables continuous solvent injection cycles that can be performed during normal plant operation. The deriming process is integrated into the continuous operation of the cryogenic equipment, allowing solvent injection sequences to occur without shutting down the main LNG production process, thereby maintaining continuous productivity.
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 effectively removes buildup in cryogenic equipment, maintaining operational efficiency by ensuring consistent solvent delivery and pressure management, thereby enhancing LNG production and reducing pressure drops.
Implementation Method 1
opening the second inlet valve of the pumping vessel to re-pressurize the pumping vessel with a process gas
Implementation Method 2
re-pressurize the pumping vessel with a process gas
Implementation Method 3
injecting a solvent into the cryogenic equipment to compensate for the pressure reduction and maintain a relatively constant pressure
Data Source
AI summary
The present invention relates to a method and an apparatus for liquefying natural gas.