Device and method for predicting sewage blockage of reverse osmosis membrane

A technology of reverse osmosis membrane and time, which is applied in the field of reverse osmosis system, can solve the problems such as the decline of membrane flux, the decline of produced water quality, and the limitation of stable operation of reverse osmosis process, achieving high accuracy, good prediction effect and excellent fitting high degree of effect

Active Publication Date: 2021-10-08
TSINGHUA UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In theory, the reverse osmosis membrane can intercept most of the pollutants in the water, so as to ensure good water quality. However, some of the intercepted pollutants will adhere to the surface of the reverse osmosis membrane, resulting in a decrease in membrane flux and a decline in the quality of the produced water. It is the core problem that limits the stable operation of the reverse osmosis process

Method used

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  • Device and method for predicting sewage blockage of reverse osmosis membrane
  • Device and method for predicting sewage blockage of reverse osmosis membrane
  • Device and method for predicting sewage blockage of reverse osmosis membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] A device for predicting reverse osmosis membrane fouling, such as figure 1 shown.

[0047] The device includes a reverse osmosis flat membrane unit 5 and a water inlet tank 2, a concentrated water tank 7 and a water product tank 8 connected to the reverse osmosis flat membrane unit 5 through a water inlet pipe, a concentrated water pipe and a water production pipe respectively; A temperature monitor 1 for real-time monitoring of the inlet water temperature, an inlet pump 3 and a pressure gauge 4 are installed on the inlet pipe, a concentrated water valve 6 is installed on the concentrated water pipe, and an electronic balance for real-time recording of the product water quality is installed at the bottom of the product water tank 8 9; The device also includes a computer 10, which is connected to the temperature monitor 1, the pressure gauge 4, the concentrated water valve 6 and the electronic balance 9 respectively.

[0048] When starting the test, the test water sampl...

Embodiment 2

[0073] A method for predicting reverse osmosis membrane fouling, comprising the steps of:

[0074] S1: Control the corrected product water flux J of the reverse osmosis membrane to remain unchanged, and measure the operating pressure ΔP of the water sample at the initial moment 0 , and the operating pressure ΔP at time t, calculate the normalized pressure at time t

[0075] S2: Calculation of normalized pressure Time rate of change at different moments;

[0076] S3: The normalized pressure at time t The membrane fouling model is used for fitting, and the specific process is as follows:

[0077] If normalized pressure When the time rate of change of increases with the increase of filtering time t, the following model 1 is adopted, and its expression is as follows:

[0078]

[0079] Among them, t is the filtration time; ΔP is the operating pressure at time t, ΔP 0 is the operating pressure at the initial moment, is the normalized pressure; j is the dimensionless ...

Embodiment 3

[0100] Model 1 is used to fit the standardized pressure-time change data of the laboratory and the actual operating RO system. The fitting results are as follows: figure 2 As shown, Model 1 is used to simulate the operating pressure change of the RO system of an actual reclaimed water plant. The water plant uses the microfiltration-reverse osmosis (MF-RO) double-membrane process to purify the secondary effluent of the urban sewage treatment plant to produce industrial reclaimed water and supplement drinking water sources. According to formula 1-3, the reaction in the system is calculated The corrected permeate flux of the RO membrane is 17LMH, and the flux J of the RO membrane is set to 17LMH in the computer.

[0101] The fitting process is: input the normalized pressure (ΔP / ΔP 0 )-time data and the expression for model one. Origin 2018 uses the least square method to fit the pressure-time curve. After multiple iterations, the fitted curve and model parameter values ​​are o...

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Abstract

The invention discloses a device and a method for predicting sewage blockage of a reverse osmosis membrane. The method comprises the following steps: the corrected water production flux J of a reverse osmosis membrane is controlled to be unchanged, the operation pressure delta P0 of a water sample at an initial moment and the operation pressure delta P at a moment t are measured, the standardized pressure delta P / delta P0 at the moment t is calculated, and the time change rate of the standardized pressure at different moments is calculated; and the standardized pressure delta P / delta P0 at the moment t is fitted through a membrane sewage blockage model, and the specific process is that if the time change rate of the standardized pressure delta P / delta P0 is increased along with the increase of the filtering time t, a first model (shown in the specification) is adopted, wherein t is the filtering time; delta P is the operation pressure at the moment t, delta P0 is the operation pressure at the initial moment, delta P / delta P0 is the standardized pressure; j is dimensionless flux; delta pi N is osmotic pressure standardized by the initial operation pressure; alpha is a compensation coefficient; k is a resistance increasing coefficient; and b is a model parameter related to the filtering initial resistance. The method can accurately simulate and predict the change of the standardized pressure along with the operation time, and is high in goodness of fit.

Description

technical field [0001] The invention relates to the field of reverse osmosis systems, in particular to a device and method for predicting reverse osmosis membrane fouling. Background technique [0002] The reverse osmosis (RO) process is more and more used in the production of high-standard industrial pure water due to its good water quality, small footprint and stable operation. In theory, the reverse osmosis membrane can intercept most of the pollutants in the water, so as to ensure good water quality. However, some of the intercepted pollutants will adhere to the surface of the reverse osmosis membrane, resulting in a decrease in membrane flux and a decline in the quality of the produced water. It is the core problem that limits the stable operation of the reverse osmosis process. In the actual project operation process, in order to ensure the stability of water production, the operation mode of constant flux and variable pressure is usually adopted. After membrane foul...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D65/10
CPCB01D65/10
Inventor 巫寅虎胡洪营徐雨晴蒋玉明崔勇
Owner TSINGHUA UNIV
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