LNG Regasification Pump Control for Variable Outlet Pressure

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Solution Overview

Problem

Existing methods for regasifying liquefied natural gas (LNG) are inflexible and require significant downtime and costs when pressure changes are needed, as they are designed for narrowly defined pressures.

Innovation Solution

A method involving a first pump unit for removing LNG from storage, a second pump unit with a variable-speed drive motor to increase pressure independently of inlet pressure, and an optional routing unit with flow paths for separation, allowing for flexible pressure adjustment without modifying existing equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the regasification process is designed for narrowly defined pressures, then the process can be optimized for specific operating conditions, but the system lacks flexibility when pressure changes are needed, requiring significant downtime and additional CAPEX and OPEX costs

Engineering Contradiction:
Improvepressure adaptabilityVSAvoiddowntime for pressure changes
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the pump system adjustable rather than fixed. The pump pressure ratio can be dynamically changed to match different LNG inlet pressures, allowing the system to adapt to varying operating conditions without requiring downtime for reconfiguration or replacement of equipment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operating parameters of the pump system by allowing the pressure ratio to be adjusted according to the inlet pressure conditions. This parameter flexibility enables the same equipment to handle different pressure scenarios, eliminating the need for downtime and additional costs associated with pressure changes in conventional fixed-ratio systems.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the pump pressure ratio is fixed, then the equipment design is simplified, but the system cannot accommodate different LNG inlet pressures without modification or replacement

Engineering Contradiction:
Improvepressure flexibilityVSAvoidpump system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The pump system is designed with dynamic adjustability, allowing the pressure ratio to be changed based on inlet pressure conditions. This dynamic capability provides pressure flexibility while maintaining a relatively simple overall system architecture, avoiding the need for multiple fixed-ratio pump sets or complex replacement procedures.

Inventive Principle:
Principle #15Dynamics

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 increases process flexibility, reduces downtime and costs by enabling pressure changes without replacing pumps, and allows for maintenance of separation columns without shutting down the entire regasification unit.

Implementation Method 1

removing liquefied natural gas from a storage tank using a first pump unit

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 2

increasing the pressure of the liquefied natural gas in the second pump unit thereby obtaining pressurized liquefied natural gas

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

vaporizing the pressurized liquefied natural gas thereby obtaining gaseous natural gas

Methodology Applied
Scientific EffectVaporization: Evaporation

Data Source

PatentEP1996855B1Method and system for the regasification of LNG
Publication Date: 2010.04.07 SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV
  • EP1996855B1 patent drawingFigure 1~2

AI summary

The present invention relates to a method for the regasification of liquefied natural gas, the method at least comprising the steps of: a) removing liquefied natural gas (10) from a storage tank (2) using a first pump unit (3); b) passing the removed liquefied natural gas (20) to and feeding it into a second pump unit (4) at an inlet pressure; c) increasing the pressure of the liquefied natural gas in the second pump unit (4) thereby obtaining pressurized liquefied natural gas (50); d) vaporizing the pressurized liquefied natural gas (50) thereby obtaining gaseous natural gas (60); wherein the second pump unit (4) discharges the pressurized liquefied natural gas (50) at a pre-selected pressure value, regardless of the inlet pressure at the second pump unit (4).