Fresh Water Generator Membrane Cleaning Trouble Detection
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Solution Overview
Problem
Existing fresh water generators using membrane separation methods face instability due to insufficient cleaning, despite control methods like adjusting ozone supply and transmembrane pressure, leading to increased chemical consumption and fouling issues.
Innovation Solution
A method and program for determining cleaning trouble by calculating temporal changes in resistance increase rates during first and second cleaning steps, using regression analysis and reference values, to adjust cleaning conditions and frequencies accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control methods like adjusting ozone supply and transmembrane pressure are used, then cleaning effectiveness is improved, but chemical consumption increases and fouling issues persist
Solution Approach 1:
The patent implements a feedback mechanism by monitoring transmembrane pressure difference trends over time and using this information to adjust cleaning operations. The system calculates the rate of pressure increase and compares it against reference values to determine when cleaning is needed, creating a closed-loop control system that responds to actual membrane condition rather than following a fixed schedule.
Solution Approach 2:
The patent changes the parameter of cleaning timing from fixed-schedule-based to condition-based by monitoring transmembrane pressure difference and its rate of change. This parameter change allows the system to optimize cleaning moments based on actual fouling conditions, preventing both premature cleaning (wasting chemicals) and delayed cleaning (allowing excessive fouling).
2Reliability
If cleaning frequency is increased to prevent fouling, then membrane performance is maintained, but operational productivity decreases
Solution Approach 1:
The patent introduces dynamic adjustment of cleaning frequency based on real-time monitoring of transmembrane pressure difference trends. Instead of static scheduled cleaning, the system adapts cleaning frequency to actual membrane fouling rates, allowing extended operation between cleanings when fouling is slow and triggering earlier cleaning when fouling accelerates.
Solution Approach 2:
The patent performs preliminary assessment of fouling trends by continuously monitoring transmembrane pressure difference before cleaning is actually needed. This allows the system to predict when cleaning will be necessary and plan accordingly, preventing both premature cleaning and excessive fouling accumulation.
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
Stabilizes the operation of fresh water generators by accurately identifying and addressing insufficiencies in the first and second cleaning steps, reducing fouling and chemical consumption.
Implementation Method 1
a filtration step of filtering water to be treated by a separation membrane to obtain filtered water
Implementation Method 2
The air scrubbing is to scrape off adhering substances on the membrane surface by introducing air bubbles to a raw water side of the membrane after ending of each filtration step, vibrating the membrane
Implementation Method 3
The backwashing is to remove the contaminants adhering on the membrane surface or inside the membrane pores by adding membrane filtered water, clear water, or a low concentration of sodium hypochlorite, and forcing it by pressure to flow in a direction opposite to a direction in a membrane filtration method
Implementation Method 4
The second cleaning step is to add a relatively high concentration of sodium hypochlorite to backwash water or using ozone-containing water in the backwash water after a plurality of the filtration steps and the first cleaning steps in order to further enhance a cleaning effect
Data Source
AI summary
The present invention provides a fresh water generator operating method and a determination program that are employed in a method for cleaning a separation membrane module following membrane filtration, and that, while various cleaning steps such as reverse pressure cleaning, air cleaning, chemical solution cleaning are taking place after completion of the membrane filtration, determines cleaning troubles by calculating a temporal change in resistance increase rate on the basis of an increase in membrane differential pressure.