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US 12,569,813 B2Granted
Method and program for determining cleaning trouble in fresh water generator
AssigneeToray Industries, Inc.
InventorsKazuki Hagawa, Kazunori Tomioka, Hiroshi Hamada
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Abstract
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.
Claims11
A method for determining cleaning trouble in a fresh water generator, the method comprising:
- a filtration step of filtering water to be treated by a separation membrane to obtain treated water;
- a first cleaning step of cleaning the separation membrane at the end of the filtration step;
- and
- a second cleaning step of chemically cleaning the separation membrane with a chemical solution having a concentration of 50 mg/L to 10,000 mg/L performed following performance of the filtration step and/or the first cleaning step a plurality of times,
- wherein when a temporal change A in a resistance increase rate between performance of the first cleaning step a plurality of times which is calculated based on a resistance increase rate during performance of the filtration step a plurality of times is larger than a reference value, insufficiency or trouble in the first cleaning step is determined, and when a temporal change B in a resistance increase rate between performance of the second cleaning step a plurality of times is larger than a reference value, insufficiency or trouble in the second cleaning step is determined,
- wherein the temporal change A in the resistance increase rate is calculated by a slope of a regression line obtained by a least square method or by the following Equation (1) and the temporal change B in the resistance increase rate is calculated by a slope of a regression line obtained by a least square method or by the following Equation (2):
- [
- Equation
-
- 1
- ]
- Δ
-
- (
- Δ
-
- R
- filt_cycle
- Δ
-
- t
- filt_cycle
- )
- Δ
-
- t
- filt_
-
- 1
-
- st
- =
- temporal
-
- change
-
- A
-
- in
-
- resistance
-
- increase
-
- rate
- (
- 1
- )
- ΔRfilt_cycle:
- resistance increase during filtration step Δtfilt_cycle:
- time of filtration step
- Δtfilt_1st:
- total filtration time between first cleaning steps
- [
- Equation
-
- 2
- ]
- Δ
-
- (
- Δ
-
- R
- after
-
- 2
-
- nd_filt
-
- _cycle
- Δ
-
- t
- filt_cycle
- )
- Δ
-
- t
- filt_
-
- 2
-
- nd
- =
- temporal
-
- change
-
- B
-
- in
-
- resistance
-
- increase
-
- rate
- (
- 2
- )
- ΔRafter2nd_filt_cycle:
- resistance increase during filtration step immediately after second cleaning step
- Δtfilt_2nd:
- total filtration time between second cleaning steps.
102 more elements
A system for determining cleaning trouble in a fresh water generator, the system being configured to perform:
- a filtration step of filtering water to be treated by a separation membrane to obtain treated water;
- a first cleaning step of cleaning the separation membrane at the end of the filtration step;
- and
- a second cleaning step of chemically cleaning the separation membrane with a chemical solution having a concentration of 50 mg/L to 10,000 mg/L performed following performance of the filtration step and/or the first cleaning step a plurality of times,
- wherein the system comprises a processor configured to:
- use a resistance increase rate during the filtration step, a temporal change A in the resistance increase rate between performance of the first cleaning step a plurality of times by a slope of a regression line obtained by a least square method or by the following Equation (3) and a temporal change B in a resistance increase rate between performance of the second cleaning step a plurality of times by a slope of a regression line obtained by a least square method or by the following Equation (4);
- record a calculation result of the calculated temporal change A in the resistance increase rate;
- and
- determine insufficiency or a trouble in the first cleaning step when the temporal change A in the resistance increase rate is larger than a reference value and determine insufficiency or a trouble in the second cleaning step when the temporal change B in the resistance increase rate is larger than a reference value
- [
- Equation
-
- 3
- ]
- Δ
-
- (
- Δ
-
- R
- filt_cycle
- Δ
-
- t
- filt_cycle
- )
- Δ
-
- t
- filt_
-
- 1
-
- st
- =
- temporal
-
- change
-
- A
-
- in
-
- resistance
-
- increase
-
- rate
- (
- 3
- )
- ΔRfilt_cycle:
- resistance increase during filtration step Δtfilt_cycle:
- time of filtration step
- Δtfilt_1st:
- total filtration time between first cleaning steps
- [
- Equation
-
- 4
- ]
- Δ
-
- (
- Δ
-
- R
- after
-
- 2
-
- nd_filt
-
- _cycle
- Δ
-
- t
- filt_cycle
- )
- Δ
-
- t
- filt_
-
- 2
-
- nd
- =
- temporal
-
- change
-
- B
-
- in
-
- resistance
-
- increase
-
- rate
- (
- 4
- )
- ΔRafter2nd_filt_cycle:
- resistance increase during filtration step immediately after second cleaning step
- Δtfilt_2nd:
- total filtration time between second cleaning steps.
105 more elements
Dependencies are inferred from the claim text.