Pumpless LNG Dispenser Using Gravity Flow and Heat Exchange
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Solution Overview
Problem
Existing LNG dispensing systems are inefficient, costly, and complex due to the need for pumps and lack of accuracy in dispensing pressurized fluids, posing environmental and safety concerns, especially when handling cryogenic liquids like LNG.
Innovation Solution
A pumpless fluid dispensing system that uses gravity-fed or pressure-fed fluid transfer between tanks, incorporating a conditioning system with a heat exchanger and programmable logic controller for accurate and efficient LNG dispensing without pumps, ensuring minimized venting and precise pressure control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If pumps are used to transfer and pressurize LNG, then the required pressure gradients for transfer and saturation are achieved, but the system complexity, energy consumption, and maintenance costs increase significantly
Solution Approach 1:
The patent removes the pump component entirely from the LNG dispensing system. Instead of using mechanical pumps to create pressure gradients, the system relies on gravity-fed flow from the bulk storage tank through the dispense tank to the vehicle tank, eliminating the complexity, energy consumption, and maintenance requirements associated with pump equipment.
Solution Approach 2:
The system uses the natural gravity flow of LNG from higher elevation storage tanks to lower elevation dispensing points to self-generate the required pressure gradients. The LNG fluid itself drives the transfer process without requiring external mechanical assistance, and the system uses portions of the LNG to condition and saturate other portions, achieving pressurization and saturation without additional equipment.
2Productivity
If pumps are installed in the dispensing system, then fluid transfer and pressurization are enabled, but the size, weight, and maintenance requirements of the system increase
Solution Approach 1:
The patent eliminates pump equipment from the dispensing system, removing the source of maintenance problems. The system achieves fluid transfer and pressurization through gravity flow and strategic heat exchange processes, requiring no mechanical moving parts that wear or fail.
Solution Approach 2:
The patent replaces the mechanical pump system with a thermal field-based system using heat exchangers. By controlling heat addition and removal at different locations in the LNG system, the desired pressure gradients and flow rates are achieved through thermal expansion and contraction rather than mechanical forcing.
3Stress or pressure
If LNG is vented to the atmosphere during dispensing, then pressure control is simplified, but environmental safety concerns and LNG waste increase
Solution Approach 1:
The patent implements a closed-loop system where vapor returned from the vehicle tank is fed back into the bulk storage tank or used for conditioning purposes. Pressure control is achieved through controlled thermal processes and vapor recovery rather than atmospheric venting, creating a closed system that prevents LNG waste and environmental contamination while maintaining proper pressure levels.
Solution Approach 2:
The patent converts what would normally be wasted vented vapor into a useful resource. The vapor returning from the vehicle tank is not discarded but instead is utilized for conditioning LNG in the dispense tank or returned to bulk storage, transforming a potential environmental hazard into a beneficial component of the system operation.
4Reliability
If traditional pump-based systems are used, then reliable fluid transfer is achieved, but the cost of purchase, operation, and maintenance increases
Solution Approach 1:
The patent removes expensive pump equipment from the system, eliminating capital costs, operational energy costs, and maintenance expenses associated with mechanical pumping. The system achieves reliable fluid transfer through gravity flow and thermal management, using simpler, less expensive components.
Solution Approach 2:
The system uses the LNG itself as the conditioning medium, circulating portions of the LNG through heat exchangers to saturate and pressurize other portions. This self-conditioning approach eliminates the need for external utilities or additional equipment, reducing both capital and operational costs while maintaining reliable operation.
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 system provides a compact, economical, and safe method for dispensing LNG, reducing energy consumption and maintenance costs while ensuring accurate mass flow measurement and environmental safety by eliminating the need for pumps and improving pressure management.
Implementation Method 1
a heat exchanger, wherein the heat exchanger includes a vaporizer configured to facilitate the transfer of energy with ambient conditions to at least partially vaporize the LNG passed through it
Implementation Method 2
the LNG in the first tank is configured to be gravity-fed or pressure-fed to the second tank
Data Source
AI summary
A fluid dispensing system may include a first tank configured to contain a first fluid and a second tank configured to contain a second fluid. The system may also include a conditioning system fluidly connected to the second tank. The conditioning system may include at least one conduit fluidly coupled to a lower region of the second tank. The conditioning system may also include a heat exchanger. In addition, the conditioning system may include at least one conduit fluidly coupled to an upper region of the second tank.