Cryogenic Liquid Pump Backup Supply With Low-Speed Standby Pressurization
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Solution Overview
Problem
In air separation apparatuses, the cryogenic liquid pump's cold standby state leads to energy loss and vaporization of cryogenic liquid, causing pressure fluctuations and inefficiency in supplying both high and low-pressure products to users.
Innovation Solution
A system with a speed-adjustable cryogenic liquid pump, liquid pump back-flow control valve, and separate product supply pipelines for low and high-pressure products, allowing the pump to operate at low speed during normal operation and high speed during shutdowns, minimizing energy loss and maintaining pressure stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the cryogenic liquid pump is kept in cold standby state during normal operation, then the startup time during shutdown is reduced, but energy loss and vaporization of cryogenic liquid occur
Solution Approach 1:
The patent applies dynamics by making the pump operational status adjustable rather than fixed. The system can dynamically switch between cold standby mode (low speed) and active supply mode (high speed) based on operational needs, resolving the contradiction between maintaining readiness (reducing startup time) and conserving energy during normal operation
Solution Approach 2:
The patent changes the operational parameters of the pump by introducing variable speed control. During normal operation, the pump runs at low speed to minimize energy consumption while maintaining cold standby capability. During shutdown or high-demand periods, the speed increases to provide full backup capacity, thus resolving the energy-loss versus startup-time contradiction through parameter adjustment
2Reliability
If the cryogenic liquid pump circulates cryogenic liquid back to storage tank during cold standby, then the pump maintains readiness, but pressure fluctuation and vaporization occur
Solution Approach 1:
The system dynamically adjusts the pump's operational mode based on system state. During cold standby, the pump operates at minimal speed just sufficient to maintain readiness without causing excessive circulation that would lead to pressure fluctuations and vaporization. This dynamic adjustment resolves the contradiction between maintaining reliability and ensuring pressure stability
3Reliability
If a backup system with storage tank and cryogenic liquid pump is used, then continuous gas product supply is ensured, but pressure variation in user's product supply pipeline occurs during switchover
Solution Approach 1:
The patent applies preliminary action by maintaining the cryogenic liquid pump in a cold standby state during normal operation, with the storage tank pre-filled with cryogenic liquid product. This preliminary preparation ensures that when shutdown or high-demand situations occur, the backup system can immediately activate without causing pressure variations, thus resolving the contradiction between ensuring continuous supply and maintaining pressure stability
Solution Approach 2:
The storage tank acts as a cushioning element, pre-stored with sufficient cryogenic liquid product to handle transition periods. This beforehand cushioning allows the system to absorb demand fluctuations without transmitting pressure variations to the user's product supply pipeline during switchover events
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 solution reduces energy loss during cold standby, ensures rapid startup, and meets user demands for both high and low-pressure products with minimal equipment modifications and installation costs.
Implementation Method 1
a speed-adjustable cryogenic liquid pump (2), which pressurizes the cryogenic liquid product sent out from the storage tank (1)
Implementation Method 2
the cryogenic liquid product is pressurized to the required pressure by a cryogenic liquid pump, and is vaporized by heat exchange to form pressurized gaseous oxygen
Data Source
AI summary
A system and method for supplying a backup product in an air separation device, as well as a system and method for supplying a lower-pressure product to a user by means of pressurization of a cryogenic liquid pump during normal operation of an air separation device, i.e., when the cryogenic liquid pump is in the cold standby state. By means of the system and method, a cryogenic liquid product taken from a storage tank is pressurized by the cryogenic liquid pump to produce a lower-pressure product by taking full advantage of the low-speed operation of the cryogenic liquid pump in the cold standby state, and the lower-pressure product is transmitted to product supply lines of a user, to achieve the function of supplying the lower-pressure product to the user. The system and method not only reduce the energy loss of the cryogenic liquid pump in the cold standby state for a long time, but also avoid the bleeding rate of the cryogenic liquid product generated by sending a part of the cryogenic liquid product back to the storage tank, so that the advantage of quickly starting the cryogenic liquid pump from the cold standby state is ensured, and the requirements of the user to the higher-pressure product and the lower-pressure product can be satisfied.