LNG Pump Column Baffle for Rapid In-Tank Maintenance
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Solution Overview
Problem
Current rail LNG tenders with in-tank submersible pumps require the tank to be completely emptied for maintenance, leading to undesirable heat loss and operational inefficiencies due to the need for re-priming external sumps during pump reactivation.
Innovation Solution
A pump column design that allows for easy and safe removal and access to the pump within a cryogenic vessel, featuring a structurally robust and manufacturable design with a bellows transition to accommodate differential movements and minimize heat loss, including a lift mechanism and sealing system to maintain vacuum integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the pump is placed in an external sump, then the pump can be accessed for maintenance, but the tank must be emptied and re-primed during maintenance causing operational disruptions
Solution Approach 1:
The pump is nested within the inner tank instead of being placed in an external sump. The pump column extends into the inner tank, allowing the pump to be positioned inside the LNG while maintaining accessibility through the column structure. This eliminates the need to empty the tank for maintenance while preserving operational continuity.
Solution Approach 2:
The pump column acts as an intermediary structure that provides access to the pump without requiring tank emptying. The column serves as a mediator between the internal pump environment and external maintenance access, allowing technicians to service the pump through the column opening while the tank remains filled and operational.
2Ease of repair
If the tank is emptied for pump maintenance, then the pump can be accessed, but significant heat loss occurs during the emptying and re-priming process
Solution Approach 1:
The pump is nested within the inner tank on the pump column, allowing maintenance access without removing LNG from the tank. This eliminates the cyclic heat loss associated with emptying and refilling the tank, as the LNG remains in place throughout the maintenance process.
Solution Approach 2:
The pump column serves as an intermediary access point that enables maintenance without exposing the cryogenic environment to ambient conditions. By providing a sealed access path through the column, the system maintains thermal isolation and prevents heat ingress that would occur during tank emptying and refilling operations.
3Productivity
If the pump remains primed in an in-tank position, then immediate pumping capability is available, but the pump positioning requires a complex column structure
Solution Approach 1:
The pump column serves multiple functions: it provides structural support for the pump, enables maintenance access, maintains sealing between inner and outer tanks, and allows pump positioning. By consolidating these functions into a single multi-functional component, the overall system complexity is reduced despite the sophisticated requirements.
Solution Approach 2:
The bellows section of the pump column provides flexible accommodation for differential thermal contraction and expansion between the inner and outer tanks. This flexible element handles the complex thermal movement requirements without requiring a rigid, overly complex structural design, thereby managing device complexity while maintaining immediate pumping capability.
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
Enables rapid and efficient maintenance without emptying the tank, reducing heat loss and operational disruptions, while maintaining the integrity of the cryogenic storage vessel.
Implementation Method 1
The column has a structurally robust design that gives consideration for high vibration mobile environments as well as differential movements of an inner tank containment shell and an outer vacuum jacket shell of the storage tank
Implementation Method 2
the inner tank being nested inside an outer tank such that a vacuum space exists between the inner and outer tanks
Data Source
Figure 1
Figure 2
AI summary
Disclosed is a pump column for use with a submersible pump in an croygenic tank, such as for use in a rail tender fueled by liquid natural gas. The pump column is configured to enable rapid removal and access to a pump submerged within a tank containing liquid natural gas.