CN-122006490-A - Film coating effect testing and calculating method and system

CN122006490ACN 122006490 ACN122006490 ACN 122006490ACN-122006490-A

Abstract

The invention relates to the technical field of membrane materials and discloses a method and a system for testing and calculating a membrane coating effect, wherein the method comprises the steps of testing a small test membrane module, testing membrane wires of the small test membrane module before and after coating, and calculating physical performance parameters of the membrane wires, including a permeability coefficient and a friction coefficient of the inner wall of the membrane wires; the method comprises the steps of coating leakage point membrane wires on an industrial membrane module, sampling and counting the ratio of membrane wires which are completely coated on a selection layer in the industrial membrane module in the total membrane wire number, recording the ratio as non-leakage point membrane wire ratio, calculating the coverage of the selection layer of the industrial membrane module, measuring the fluid parameters of each port of the industrial membrane module, combining the physical performance parameters of the membrane wires with the ratio of the non-leakage point membrane wires, and calculating the average coverage of the selection layer of the membrane wires with coating leakage points in the industrial membrane module by using a simultaneous material conservation equation, a friction pressure loss relation equation and a permeation resistance loss relation equation. The invention is particularly useful for evaluating the selective layer coverage of hollow fiber membranes employing an internal coating process.

Inventors

YIN DENGGUO
CHEN ZHUO
DU WENTAO
HOU WEN
WU YUANMING
GUO JUNDONG
LI YUN
ZHUANG YUANFA
DENG YI

Assignees

东方电气集团东方锅炉股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260116

Claims (10)

1. A film coating effect test and calculation method, characterized by comprising: testing the membrane wire of the small-scale membrane assembly before and after coating, and calculating physical performance parameters of the membrane wire, including permeability coefficient and friction coefficient of the inner wall of the membrane wire; sampling and counting the proportion of the membrane wires which are completely coated by a selection layer in the industrial membrane assembly in the total membrane wire number, and marking the proportion as the non-leakage membrane wire proportion; and calculating the coverage of the selective layer of the industrial membrane component, namely measuring the fluid parameters of each port of the industrial membrane component, including the pressure and flow of a feed gas inlet, a residual gas outlet and a permeation gas outlet, and calculating the average coverage of the selective layer of the membrane wire with the coating leakage point in the industrial membrane component by combining the physical performance parameters of the membrane wire with the non-leakage point membrane wire ratio, a simultaneous material conservation equation, a friction pressure loss relation equation and a permeation resistance loss relation equation.
2. The method for testing and calculating the film coating effect according to claim 1, wherein in the test of the small test film assembly, the test is performed before and after film wire coating of the small test film assembly, and the method comprises the following steps: The method comprises the steps of controlling gas in a feed gas cylinder to sequentially pass through a feed gas valve to regulate flow, a feed gas flow meter to measure flow q 1 and a feed gas pressure meter to measure pressure p 1 , and then entering a small test membrane module measuring device from a feed gas inlet, wherein at least 1 membrane wire is arranged in the small test membrane module measuring device, the part of the feed gas which passes through a membrane wire selection layer and reaches the outer side of the membrane wire is permeated gas, the part of the feed gas which flows out of a permeated gas outlet through a pipeline on the inner side of the membrane wire is permeated residual gas, the permeated residual gas flow q 2 is measured by the permeated residual gas flow meter, the pressure difference deltap between the feed gas inlet and the permeated residual gas outlet is measured by the pressure difference meter, and then calculating and obtaining the pressure p 2 of the permeated residual gas outlet; Taking the permeate gas passing through the membrane wires out of the small test membrane module measuring device by adopting inert purge gas, wherein in the process, the inert purge gas from a purge gas cylinder enters a purge gas inlet of the small test membrane module measuring device after the flow rate is regulated by a purge gas valve and the flow rate q Purging is measured by a purge gas flow meter, and flows out of a permeate gas outlet after the permeate gas is taken out; After the osmotic air is measured by the osmotic pressure meter and the pressure p 3 and the flow q 3 , the osmotic air enters the gas detector to measure the ratio y Infiltration process of non-sweeping gas components in the osmotic air.
3. The method for testing and calculating the film coating effect according to claim 2, wherein in the test of the small test film assembly, the calculating the film wire physical performance parameter comprises: The osmotic coefficients α φ0% and α φ100% before and after coating were calculated by the osmotic resistance loss relation equation: Wherein, the superscript ". X" represents the measurement result of the hollow fiber membrane substrate directly adopting the uncoated selective layer; The coefficient of friction f φ100% of the inner wall of the film wire under the fully coated film wire was calculated by the modified darcy-Wei Siba hz formula: wherein ρ g is the density of the gas inside the membrane filament.
4. The method for testing and calculating the membrane coating effect according to claim 1, wherein when the industrial membrane module is used for coating the leakage point membrane wires, the method for judging the membrane wires with the completely coated selective layers in the industrial membrane module comprises the steps of coating a layer of surfactant on the cross section of a hollow fiber membrane wire bundle at the upper end closure head of the industrial membrane module, pumping air at the permeation side of the membrane module at a preset vacuum degree and flow rate, and observing the change condition of a surfactant bubble membrane, wherein the bubble membrane is the membrane wires with the completely coated selective layers when being kept still, and the bubble membrane is the membrane wires with the incompletely coated leakage points when being pumped and sunk into a membrane wire tube.
5. The method for testing and calculating the coating effect of the membrane according to claim 4, wherein the step of sampling and counting the proportion of the membrane wires which are completely coated by the selection layer in the industrial membrane assembly in the total membrane wire number when the industrial membrane assembly is coated with the leakage point membrane wire is performed comprises the steps of equally dividing the sampling area into a plurality of fan-shaped areas with the same shape and area according to the symmetry and the uniformity of the coverage of the selection layer, randomly selecting partial areas for counting during counting, and sucking and sinking the bubble film in the selection area into the membrane wire tube, and further calculating the proportion eta of the membrane wires which are completely coated by the selection layer in the total membrane wire number.
6. The method for testing and calculating the film coating effect according to claim 1, wherein in the test of the small test film assembly, the length of the film wire to be tested is 0.08-0.25 m, the measuring range of the differential pressure gauge is selected according to the different lengths of the film wire to be tested, and the maximum measuring range of the differential pressure gauge corresponding to each 0.1m of the film wire length is 100-200 Pa.
7. The method for testing and calculating the membrane coating effect according to claim 1, wherein in the statistics of the membrane filaments of the industrial membrane module coating leakage points, after a layer of surfactant is coated on the section of the hollow fiber membrane filament bundle at the end enclosure of the upper end of the industrial membrane module, the pressure difference between the ambient pressure P 0 and the pressure P 3 at the permeate gas outlet is 5-15 kPa during the pumping operation; In the calculation of the coverage of the selective layer of the industrial membrane component, the pressure difference range between the inlet pressure P 1 and the ambient pressure P 0 adopted in the measurement of the fluid parameters of each port of the industrial membrane component is 20-100 kPa.
8. A film coating effect test system for use in the film coating effect test and calculation method of claim 1, wherein the film coating effect test system comprises a small test film assembly test subsystem, the small test film assembly test subsystem comprising a small test film assembly measurement device, a feed gas input assembly, a purge gas input assembly, a permeate gas measurement assembly, a differential pressure gauge and a permeate gas flow meter; At least 1 membrane wire is arranged in the small test membrane component measuring device, the part of the feed gas which passes through the membrane wire selection layer and reaches the outer side of the membrane wire is permeated gas, and the part of the feed gas which flows out from the permeated gas outlet through the pipeline on the inner side of the membrane wire is permeated gas; The feed gas inlet of the small test membrane component measuring device is connected with the feed gas input component and the first end of the differential pressure meter, the purge gas inlet is connected with the purge gas input component, the permeate gas outlet is connected with the permeate gas measuring component, and the permeate gas outlet is connected with the second end of the differential pressure meter and the permeate gas flowmeter.
9. The film coating effect test system of claim 8, wherein the feed gas input assembly comprises a feed gas cylinder, a feed gas valve, a feed gas flow meter, and a feed gas pressure gauge connected in sequence, the feed gas pressure gauge being connected to a feed gas inlet; The purge gas input assembly comprises a purge gas cylinder, a purge gas valve and a purge gas flow meter which are sequentially connected, and the purge gas flow meter is connected with a purge gas inlet; The osmotic gas measurement assembly comprises an osmotic gas pressure meter, an osmotic gas flow meter and a gas detector which are sequentially connected, and the osmotic gas pressure meter is connected with an osmotic gas outlet.
10. A film coating effect test system for use in the film coating effect test and calculation method of claim 1, wherein the film coating effect test system comprises an industrial film assembly selective layer coverage test subsystem comprising an industrial film assembly, a feed gas control assembly, a permeate gas control assembly, and a retentate gas measurement assembly; The feed gas inlet of the industrial membrane component is connected with the feed gas control component, the permeate gas outlet is connected with the permeate gas control component, and the permeate gas outlet is connected with the permeate gas measuring component; the feed gas control assembly comprises a blower, a first flowmeter, a first valve and a first pressure gauge which are sequentially connected, and the first pressure gauge is connected with a feed gas inlet of the industrial membrane assembly; the permeate gas control assembly comprises a vacuum gauge, a third flowmeter and a vacuum pump which are sequentially connected, and the vacuum gauge is connected with a permeate gas outlet of the industrial membrane assembly; The residual gas seepage measurement assembly comprises a second pressure gauge and a second flowmeter which are connected with the residual gas seepage outlet.

Description

Film coating effect testing and calculating method and system Technical Field The invention relates to the technical field of film materials, in particular to a film coating effect testing and calculating method and system. Background Membrane separation technology is a commonly used separation and concentration technology of mixed gas or mixed solution in industry, and the part which plays an effective role in separation is a selective layer on a membrane, wherein the selective layer can realize separation of components by utilizing different permeabilities of components in feed when the components pass through the membrane. Hollow fiber membranes are widely used in industry because of their extremely high packing density (high membrane area per unit volume), and the coating process of coating a casting solution on a hollow fiber membrane substrate to construct a selective layer is a key step in the manufacturing process of such membrane modules. If the selection layer is coated outside the hollow fiber membrane wires, the membrane wires are in an oscillation state under the flow of gas due to the longer length of the membrane wires when the membrane assembly actually runs, the selection layer coated on the outer surfaces of the membrane wires can be damaged and fall off due to mutual friction collision among the membrane wires, and the selection layer is coated inside the hollow fiber membrane wires, so that the mechanical friction damage of the selection layer in running can be avoided, but in the inner coating process of the membrane assembly, the problem that the selection layer is not completely coated on the surface of the membrane base material easily occurs due to the reasons that air bubbles are entrained in casting solution, the membrane wires are locally bent, the process operation is poor and the like, leakage points are formed, and the corresponding membrane wires become coating leakage point membrane wires. When the mixed gas passes through the membrane wires, a short circuit is formed, and the mixed gas cannot be effectively separated, so that the overall selectivity of the membrane assembly is reduced, and the product concentration cannot meet the separation requirement. Therefore, it is necessary to examine and evaluate the coating effect of the selective layer of the membrane module after the inner coating. The industrial hollow fiber membrane component is formed by parallelly packaging thousands of membrane wires, the coverage condition of a selection layer of each membrane wire cannot be directly observed after the coating, and whether the coating of the selection layer of the membrane component is qualified or not is difficult to judge. Among the various indirect indexes, the pressure and flow of each passage opening of the industrial membrane module are the most easily obtained measurement parameters, and in general, the higher the pressure difference between the feed gas inlet and the permeate gas outlet is, the smaller the permeate gas amount is, which means that the higher the selective layer coverage is, the better the coating effect is. However, whether the selective layer of the membrane module is coated or not cannot be judged according to the relative magnitude of the pressure difference, and even the membrane module with the largest pressure difference in the same batch of membrane modules may not meet the coating qualification requirement. At present, no literature exists yet to explain the quantitative relation between the pressure, flow and selective layer coverage of each channel opening of the membrane module, and in view of the fact that the selective layer coverage is an important judgment index for subsequent screening, recoating, plugging, repairing or discarding treatment, the method for evaluating and evaluating the selective layer coverage of the industrial membrane module based on a certain test method has very important industrial application value. The conventional detection scheme (such as the patent CN104353364B, CN114130205B and the patent CN 115753332A) aiming at the small test membrane component only sets a pressure gauge at the upstream of the small test membrane component, the downstream lacks a pressure detection point, the pressure difference of fluid before and after passing through a membrane wire pipe cannot be obtained, on the other hand, even if the pressure gauge is added at the downstream of the membrane wire, if the selected measuring range of the pressure gauge is directly the same as the specifications of the pressure gauges at other positions of the small test component test system, the measurement error of the pressure gauge exceeds 100 percent even if the high-precision pressure gauge with the precision grade of 0.1 (precision grade) is adopted, therefore, the conventional test scheme cannot accurately calculate the friction coefficient f of the inner wall of the membrane wire, and under the condition of lacking the parameter, the referenc