CN-121994742-A - Rapid detection method for rolling oleic acid value in emulsion for cold rolling production

CN121994742ACN 121994742 ACN121994742 ACN 121994742ACN-121994742-A

Abstract

The invention discloses a rapid detection method of a rolling oil acid value in emulsion for cold rolling production, which comprises the following steps of S1, taking cold rolling emulsion to be detected, filtering, sequentially mixing and extracting an organic solvent, performing high-speed centrifugal separation and negative pressure rotary evaporation operation on the cold rolling emulsion to be detected, further obtaining a rolling oil sample to be detected, S2, preparing rolling oil standard samples with different acid values, S3, detecting the rolling oil standard samples with different acid values and the rolling oil samples to be detected respectively by using an infrared spectrum method, obtaining infrared spectra of corresponding samples, thereby obtaining a standard curve of the rolling oil acid value, and obtaining the acid value of the rolling oil in the cold rolling emulsion to be detected by comparison. The method can quickly read and acquire the acid value of the rolling oil in the field emulsion, has higher result accuracy, can meet the requirements of quick measurement and quick adjustment of the field production of the modern cold rolling unit, and has higher practicability.

Inventors

QU PEILEI
HONG TAO
HE XIAOLEI
YE XUEWEI
OU RONGFENG
CHEN JUN

Assignees

宝山钢铁股份有限公司
宝钢湛江钢铁有限公司

Dates

Publication Date: 20260508
Application Date: 20241108

Claims (9)

1. A rapid detection method of a rolling oleic acid value in emulsion for cold rolling production is characterized by comprising the following steps: S1, taking cold rolling emulsion to be detected, filtering, and sequentially carrying out mixing and extraction of an organic solvent, high-speed centrifugal separation and negative pressure rotary evaporation operation on the cold rolling emulsion to be detected, so as to obtain a rolling oil sample to be detected; s2, preparing rolling oil standard samples with different acid values; And S3, respectively detecting rolling oil standard samples with different acid values and rolling oil samples to be detected by using an infrared spectrum method, obtaining infrared spectra of the corresponding samples, thereby obtaining a standard curve of the rolling oil acid value, and obtaining the acid value of the rolling oil in the cold-rolling emulsion to be detected by comparison.
2. The method for rapidly detecting the rolling oleic acid value in an emulsion for cold rolling production according to claim 1, wherein the process of the step S1 is as follows: S11, taking cold-rolled emulsion to be detected, and filtering the cold-rolled emulsion in filtering equipment with a microporous filter; S12, pouring an organic solvent into the filtered cold-rolled emulsion to be tested, putting the cold-rolled emulsion into a high-speed stirrer for stirring and mixing, and extracting rolling oil in the emulsion to be tested into the organic solvent; S13, immediately performing centrifugal separation after stopping stirring the mixed solution of the cold-rolled emulsion to be detected and the organic solvent; S14, taking the upper organic solvent phase clear liquid of the centrifuged liquid, and placing the upper organic solvent phase clear liquid in a hot water bath for negative pressure rotary evaporation to obtain a rolling oil sample to be detected.
3. The method for rapidly detecting a rolling oleic acid value in an emulsion for cold rolling production according to claim 2, wherein in the step S11, the sampling amount of the cold-rolled emulsion to be detected is 400-800 ml, and the emulsion with a concentration of 1.5% or more is selected as the cold-rolled emulsion to be detected.
4. The method for rapid detection of rolling oleic acid value in emulsion for cold rolling production according to claim 2, characterized in that in step S12: The organic solvent is one of butanone, dichloroethane, isopropanol and petroleum ether, and the addition amount of the organic solvent is 40-100 ml; The stirring speed of stirring and mixing is more than or equal to 8000rpm, and the stirring time is 5-10 min.
5. The method for rapidly detecting a rolling oleic acid value in an emulsion for cold rolling production according to claim 2, wherein the centrifugal separation in the step S13 is as follows: and respectively placing the mixed solution into a multi-tube polypropylene centrifuge tube, controlling the addition of 15mL of the mixed solution into each tube, and placing the mixed solution on a high-speed centrifuge for centrifugal separation for 5-15 min.
6. The method for rapid detection of rolling oleic acid value in emulsion for cold rolling production according to claim 2, characterized in that the procedure of step S14 is as follows: and taking 30-90 mL of supernatant of the upper organic solvent phase of the centrifuged liquid, placing the supernatant in a rotary evaporator, performing negative pressure rotary evaporation in a hot water bath at 60-85 ℃, controlling the negative pressure at-640+/-20 mm Hg, and evaporating to remove the organic solvent and trace water to obtain the rolling oil to be measured.
7. The method for rapidly detecting the rolling oil acid value in the emulsion for cold rolling production according to claim 1, wherein in the step S2, the rolling oil standard samples with different acid values are prepared as follows: S21, taking the crude oil of the rolling oil with the emulsion used by the field unit, titrating the acid value, and marking the titrated acid value as a 1# standard sample; S22, taking crude oil of rolling oil, adding mineral oil with different addition amounts, heating to fully mix the crude oil, then titrating an acid value, and marking the crude oil as a No. 2 standard sample, a No. 3 standard sample, a No. 4 standard sample and a No. 5 standard sample according to the addition amounts of the mineral oil, wherein the addition amounts of the mineral oil in the No. 2 standard sample, the No. 3 standard sample, the No. 4 standard sample and the No. 5 standard sample are arranged from low to high.
8. The method for rapid detection of rolling oleic acid value in emulsion for cold rolling production according to claim 7, wherein the mineral oil is Kunlun L-HM46 hydraulic oil.
9. The method for rapidly detecting the rolling oleic acid value in the emulsion for cold rolling production according to claim 1, wherein the specific process of the step S3 is as follows: S31, preparing an instrument, opening an infrared spectrometer, simultaneously opening a high-purity nitrogen valve, and purging nitrogen for at least 20 minutes for the first time until no interference peak exists in the infrared spectrometer; S32, setting an instrument, opening infrared software, and setting scanning of an infrared spectrometer as scanning blank before each scanning of a sample; S33, scanning rolling oil standard samples with different acid values sequentially after scanning blank, storing an infrared spectrum, and cleaning a sample cell used for measurement after each sample scanning; S34, manufacturing a standard curve, opening infrared spectrum data processing software, setting the path length of an infrared data processing method, setting peak height values of the peak value of a measured standard sample at 1710cm -1 wave numbers, sequentially introducing infrared maps of rolling oil standard samples with different acid values, and correspondingly inputting the acid values of the titrated standard samples, thereby obtaining a standard curve of the rolling oil acid values; s35, standard curve analysis, namely calculating the correlation coefficient of a standard curve of the rolled oleic acid value by using infrared spectrum data processing software, wherein if the correlation coefficient is more than 0.995, the standard curve of the rolled oleic acid value meets the requirement, and if not, rescanning or reconfiguring an emulsion standard sample; S36, sample analysis, namely taking out a clean sample pool, loading a rolling oil sample to be measured, placing back to a pool seat, closing a top cover, continuing to purge nitrogen, scanning the rolling oil sample to be measured, and preserving an infrared spectrum; And S37, opening a standard curve of the rolling oil acid value, and calculating the acid value of the rolling oil in the cold-rolling emulsion to be measured according to a linear interpolation fitting principle.

Description

Rapid detection method for rolling oleic acid value in emulsion for cold rolling production Technical Field The invention relates to the technical field of steel cold rolling production, in particular to a rapid detection method of a rolling oleic acid value in emulsion for cold rolling production. Background Modern steel production enterprises usually carry out cold rolling processing on part of steel materials, emulsion is prepared in the cold rolling process, namely, industrial desalted water and rolling oil are prepared into liquid with concentration of usually less than or equal to 5% and are sprayed onto strip steel and rollers, the emulsion has excellent lubricating and cooling effects, so that the use wear of the rollers, the energy consumption of a rolling mill and the surface quality of the strip steel depend on the performance of the emulsion, a large amount of detection is required in daily cold rolling production, the performance of the emulsion covers multiple aspects, and common detection items are the detection of saponification value and acid value of the rolling oil in the emulsion. The acid number is one of the most important conventional tests for evaluating the performance of fats and oils, and represents the milligrams of potassium hydroxide (KOH) required to completely neutralize the free carboxylic acid groups in 1 gram of the rolling oil material, and, in chemical principle, directly represents the amount of fatty acids free in the fat and oil sample. Unlike conventional industrial oils, the acid value is one of the most important performance detection indexes for cold rolling oil, and since cold rolling oil itself contains a large amount of free fatty acids as a lubricating additive and also contains a large amount of animal and vegetable oils and fats and synthetic oils, free fatty acids are extremely easily produced under aqueous conditions. The detection is mainly used for judging whether the rolling oil in cold rolling production is deteriorated or whether the lubricating property can meet the production requirement, and the quality assurance of the whole production is highly dependent on the acid value. As described above, since the emulsion is used for cold rolling production and the rolling oil therein is detected, when detecting the state of the cold rolling emulsion, it is necessary to separate the oil from the water in the emulsion on site to obtain the rolling oil therein. The process adopts heating negative pressure rotary evaporation to remove partial water, heating (more than or equal to 80 ℃) the emulsion after a large amount of sodium chloride is added to accelerate the oil-water delamination speed, oil-water separation phenomenon can occur after long-time operation, then the oil phase is sampled and then the rolled oil is extracted by dissolving organic solvents such as butanone, then the extraction liquid is sampled and heated to remove the solvent, finally the rolled oil sample is obtained, then the titration of standard potassium hydroxide solution is carried out, the reaction end point is also carried out by using a phenolphthalein indicator in the process, the operation is time-consuming and labor-consuming, the titration operation using the reagents is usually carried out in a laboratory, the time required from sampling to obtaining the final titration result is usually more than one day in actual production working condition, and the quick adjustment requirement on a machine set is often difficult to meet. Therefore, how to quickly measure the rolling oleic acid value of the emulsion used in the cold rolling production, and simplify the measured process operation are very important and practical. Based on the above, technical materials of methods for detecting relevant acid values are searched in the field, and mainly gather in some aspects as follows: Japanese patent JP20190826 proposes a device for determining the degree of degradation of oil, a program for determining the degree of degradation of oil and a method for determining the degree of degradation of oil, wherein the oil to be measured is placed in a special optical instrument, a professional camera device is used for recording the color of the oil and analyzing the data of computer chromaticity, and standard oil samples with different acid values are compared in color, so that the approximate acid value range of the oil can be rapidly determined. The Chinese patent application number 202011007644.5 proposes a full-automatic fatty acid value measuring system and method for grains, specifically, a machine vision judging principle is also used, a flow of manually and visually observing color change of a phenolphthalein reagent in the traditional chemical titration process is automatically completed by using a machine, so that the labor amount of rolling oleic acid value measurement can be integrally saved, the process still faces the process of time-consuming demulsification for preparing rolling oil