CN110045036B - Regeneration capacity evaluation method of industrial lubricating oil regeneration adsorbent - Google Patents
Regeneration capacity evaluation method of industrial lubricating oil regeneration adsorbent Download PDFInfo
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- G—PHYSICS
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Abstract
The invention discloses a regeneration capacity evaluation method of an industrial lubricating oil regeneration treatment adsorbent, which adopts a quantitative detection method of furfural content in oil liquid to respectively evaluate the change of furfural content in base oil before and after regeneration treatment of a regeneration adsorbent to be evaluated, wherein the larger the reduction amount of furfural content in oil liquid after the treatment of the regeneration adsorbent to be evaluated is, the better the regeneration capacity of the regeneration adsorbent is; the characterization method provided by the invention has good accuracy and simple operation, and plays an important role in evaluating the performance of the regenerated adsorbent.
Description
Technical Field
The invention belongs to the technical field of industrial lubricating oil regeneration treatment, and particularly relates to a regeneration capacity evaluation method of an industrial lubricating oil regeneration adsorbent.
Background
The industrial lubricating oil mainly comprises hydraulic oil, gear oil, turbine oil, compressor oil, refrigerator oil, transformer oil, vacuum pump oil, bearing oil, metal processing oil, antirust oil, cylinder oil, heat treatment oil, heat conduction oil and the like. The industrial lubricating oil mainly plays important roles of insulation, lubrication, heat dissipation, hydraulic transmission and the like in the operation process of equipment. In the actual operation process, the oil product is inevitably aged due to the influence of the external temperature, oxygen, moisture, metal catalysis and the like, and polar aging products such as alcohol, aldehyde, ketone, carboxylic acid, ester and the like are generated.
At present, due to the fact that the cost is high when new oil is replaced, a plurality of environmental problems are caused when waste oil is treated, and enterprises mostly adopt adsorbents such as silica gel, diatomite, ion exchange resin and activated alumina to carry out regeneration treatment on deteriorated and deteriorated oil, so that the service life of the oil is prolonged. However, the manufacturers for preparing the oil treatment adsorbent in the market are various, and no clear evaluation index is provided for the regeneration performance of the oil treatment adsorbent, so that great confusion is brought to the selection of the oil treatment adsorbent and the purchase of oil treatment equipment of users. At present, for the performance evaluation of the oil treatment adsorbent, the chemical composition, the shape, the active surface, the activation temperature, the optimal working temperature and the components capable of being adsorbed of the oil treatment adsorbent are mostly used for description, and no characterization means is provided for the adsorption capacity of the oil treatment adsorbent.
Disclosure of Invention
In order to solve the problems in the prior art, the invention aims to provide an evaluation method for the regeneration capacity of an industrial lubricating oil regeneration treatment adsorbent, which can effectively evaluate the regeneration performance of different types and models of oil treatment adsorbents, select products with excellent regeneration performance for users, and provide an analysis means for research personnel of the regeneration adsorbents; the evaluation method is simple and convenient and has good accuracy, and plays an important role in the development of the oil regeneration treatment adsorbent technology.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a regeneration capacity evaluation method of an industrial lubricating oil regeneration treatment adsorbent is characterized in that a quantitative detection method of furfural content in oil is adopted to respectively evaluate the change of furfural content in base oil before and after regeneration treatment of a regeneration adsorbent to be evaluated; the method comprises the following steps:
1) respectively pretreating the base oil and the regenerated adsorbent to be evaluated; the pretreatment process specifically comprises the following steps: carrying out vacuum drying on the base oil and the regenerated adsorbent to be evaluated for 2-6 h;
2) adding furfural which accounts for no more than 2 wt% of base oil into the pretreated base oil, stirring for 30-90 min at the rotation speed of 500-1200 r/min until the mixture is uniform, heating the base oil containing the furfural to 40-60 ℃, adding the pretreated regenerated adsorbent to be evaluated, adding the regenerated adsorbent to be evaluated, wherein the mass fraction of the added regenerated adsorbent to be evaluated is no more than 5% of that of the base oil containing the furfural, stirring for 20-60 min at the condition of 200-800 r/min, and filtering by using filter paper to obtain regenerated base oil;
3) the representation of the regeneration capacity of the regenerated adsorbent is completed by comparing the reduction amount of the furfural content in the base oil before and after the regeneration treatment of the adsorbent to be evaluated; namely, the larger the reduction amount of the furfural content in the oil liquid after being treated by the regenerated adsorbent to be evaluated, the better the regeneration capability of the regenerated adsorbent.
Preferably, the method for quantitatively detecting the furfural content in the oil liquid is liquid chromatography.
Preferably, the quantitative determination method for the furfural content in the oil liquid adopts an instrument of high performance liquid chromatography.
Preferably, the base oil in step 1) is a mineral oil base oil or a synthetic PAO base oil.
Preferably, the kinematic viscosity of the base oil in the step 1) at 40 ℃ is not more than 50.6mm2/s。
Preferably, the grade of furfural purity in step 1) is analytical purity.
Preferably, the regenerated adsorbent to be evaluated in the step 1) is silica gel, diatomite, ion exchange resin, activated alumina, a silicon-aluminum adsorbent or an adsorbent which is obtained by removing polar aging products in oil and is subjected to oil liquid regeneration treatment through clay.
Preferably, the filter paper in step 1) is qualitative filter paper, and the filtering speed of the filter paper is medium or slow.
The invention provides a characterization method of the regeneration capacity of an oil product regeneration adsorbent on the basis of data of analysis of regeneration treatment work of a large amount of lubricating oil, hydraulic oil, insulating oil and the like in operation. The characterization method provided by the invention has good accuracy and simple operation, and plays an important role in evaluating the performance of the regenerated adsorbent.
In addition, the evaluation method provided by the invention is applied to the model selection work of the regeneration oil filter, can compare the regeneration performance of the regeneration adsorbent used in the regeneration oil filter, improves the model selection efficiency of the owner regeneration oil filter, avoids resource waste caused by improper model selection, provides an important basis for the research field of the regeneration adsorbent, and promotes the development and application of the oil regeneration adsorbent.
Detailed Description
The present invention will be described in further detail with reference to the following embodiments.
The first embodiment is as follows:
for four commercially available regenerated adsorbents, respectively, J-614 type silica gel, CDX-2 type diatomaceous earth, 4M type activated alumina and 1M type activated alumina, and mineral insulating oil (kinematic viscosity at 40 ℃ C. is 5.02 mm)2And/s) are respectively pretreated. Accurately measuring four parts of mineral insulating oil each 100g and regenerated adsorbent each 2g, and vacuum drying for 4h to obtain four groups of base oil and regenerated adsorbent respectively.
Respectively adding 0.1g of furfural of analytical grade into four groups of base oil, stirring for 40min at the rotation speed of 600r/min until the furfural content in the oil liquid is uniform, carrying out quantitative detection on the furfural content in the oil liquid by adopting high performance liquid chromatography according to SH/T0812-2010 (determination method for 2-furfural and related components in mineral insulating oil), heating the base oil added with furfural to 40 ℃, respectively adding 2g of regenerated adsorbent, stirring for 30min at the speed of 300r/min, filtering by using slow quantitative filter paper to obtain regenerated base oil, and carrying out quantitative detection on the furfural content in the base oil again. The results of furfural content determination are shown in table 1.
TABLE 1 evaluation data of regeneration capacities of different regenerated adsorbents
Therefore, through the comparative test of the regeneration performance of the actual four oil regeneration adsorbents, the regeneration performance of the four oil regeneration adsorbents is ranked as follows: 1M type activated alumina > 4M type activated alumina > J-614 type silica gel > CDX-2 type diatomaceous earth. The 1M type activated alumina has optimal regeneration performance, and can better remove polar aging products in oil compared with other three adsorbents.
The four adsorbents listed in table 1 are adopted to regenerate the phosphate fire-resistant oil which is operated in a power plant for nearly ten years, and the regeneration effect is shown in table 2. As can be seen from Table 2, the 1M type activated alumina with the strongest regeneration capability has the best regeneration treatment effect, the largest increase amplitude of the resistivity of the anti-fuel oil and the largest reduction amplitude of the acid value, and the regeneration effect of the three regeneration adsorbents after treatment is not mud-free, and the sequence of the regeneration effects of the rest three regeneration adsorbents is consistent with the regeneration performance sequence shown in Table 1.
TABLE 2 comparison of results of operating fire resistant oil of a certain power plant after treatment with different regenerated adsorbents
Example two:
three commercially available regenerated adsorbents were H107 type ion exchange resin, 1060 type clay and CJ type silica-alumina adsorbents, and synthetic PAO base oil (kinematic viscosity at 40 ℃ C. of 32.12 mm)2And/s) are respectively pretreated. Accurately weighing 100g of each of the synthetic PAO base oil and 2g of each of the regenerated adsorbents, and performing vacuum drying for 6 hours to respectively obtain three groups of base oil and regenerated adsorbents.
Respectively adding 0.3g of furfural with analytical grade into three groups of PAO base oil, stirring for 80min at the rotation speed of 1100r/min until the furfural is uniform, quantitatively detecting the furfural content in the oil liquid by adopting high performance liquid chromatography according to SH/T0812-2010 (determination method for 2-furfural and related components in mineral insulating oil), heating the base oil added with furfural to 60 ℃, respectively adding 2g of regenerated adsorbent, stirring for 50min at the speed of 800r/min, filtering by using medium-speed quantitative filter paper to obtain regenerated base oil, and quantitatively detecting the furfural content in the base oil again. The results of furfural content determination are shown in table 3.
TABLE 3 evaluation data of regeneration capacities of different regenerated adsorbents
Therefore, through the comparative test of the regeneration performance of the three actual oil regeneration adsorbents, the regeneration performance is ranked as follows: CJ type silicon aluminum adsorbent > H107 type ion exchange resin > 1060 type white clay. The CJ type silicon-aluminum adsorbent has the optimal regeneration performance, and compared with the other two adsorbents, the CJ type silicon-aluminum adsorbent can better remove polar aging products in oil.
After the three adsorbents listed in the table 3 are adopted to perform regeneration treatment on the turbine oil which runs in a power plant for eight years, the regeneration effect is shown in the table 4. It can be seen from table 4 that the CJ-type silica-alumina adsorbent having the strongest regeneration ability has the best regeneration treatment effect, the greatest reduction range of the chroma, acid value and demulsification degree of the operating turbine oil, no sludge is produced after treatment, and the sequence of the regeneration effects of the other two regenerated adsorbents is consistent with the sequence of the regeneration performances shown in table 3.
TABLE 4 comparison of results of turbine oils from certain power plant operations treated with different regenerated sorbents
Example three:
for three commercially available regenerated adsorbents, 650C type ion exchange resin, ZX104 type oil regenerated adsorbent, SY11 type silica gel adsorbent, and mineral base oil (kinematic viscosity at 40 deg.C)Is 45.33mm2And/s) are respectively pretreated. Accurately measuring 100g of mineral base oil and 5g of regenerated adsorbent, and vacuum drying for 4h to obtain three groups of base oil and regenerated adsorbent.
Adding 1g of furfural of analytical grade into three groups of mineral base oil respectively, stirring for 90min at the rotation speed of 1200r/min until the furfural is uniform, carrying out quantitative detection on the furfural content in the oil liquid by adopting high performance liquid chromatography according to SH/T0812-. The results of furfural content determination are shown in table 5.
TABLE 5 evaluation data of regeneration capacities of different regenerated adsorbents
Therefore, through the comparative test of the regeneration performance of the three actual oil regeneration adsorbents, the regeneration performance is ranked as follows: ZX104 type oil regeneration adsorbent > SY11 type silica gel adsorbent > 650 type C ion exchange resin. The regeneration performance of the ZX104 type oil regeneration adsorbent is optimal, and compared with other two adsorbents, the adsorbent can better remove polar aging products in oil.
The three adsorbents listed in Table 5 are adopted to regenerate the insulating oil of a power plant operating for five years, and the regeneration effect is shown in Table 6. As can be seen from table 6, the ZX 104-type oil-regenerated adsorbent having the strongest regeneration capacity has the best regeneration treatment effect, the largest reduction range of the chromaticity, acid value and dielectric loss factor of the operating insulating oil, the largest increase range of the resistivity and interfacial tension, and the regeneration effect ranks of the other two regenerated adsorbents are consistent with the regeneration performance ranks shown in table 5.
TABLE 6 comparison of results of turbine oils from certain power plant operations treated with different regenerated adsorbents
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (8)
1. A regeneration capability evaluation method of an industrial lubricating oil regeneration treatment adsorbent is characterized by comprising the following steps: evaluating the change of the furfural content in the base oil before and after the regeneration treatment of the regenerated adsorbent to be evaluated by adopting a quantitative detection method of the furfural content in the oil liquid; the method comprises the following steps:
1) respectively pretreating the base oil and the regenerated adsorbent to be evaluated; the pretreatment process specifically comprises the following steps: carrying out vacuum drying on the base oil and the regenerated adsorbent to be evaluated for 2-6 h;
2) adding furfural which accounts for no more than 2 wt% of base oil into the pretreated base oil, stirring for 30-90 min at the rotation speed of 500-1200 r/min until the mixture is uniform, heating the base oil containing the furfural to 40-60 ℃, adding the pretreated regenerated adsorbent to be evaluated, adding the regenerated adsorbent to be evaluated, wherein the mass fraction of the added regenerated adsorbent to be evaluated is no more than 5% of that of the base oil containing the furfural, stirring for 20-60 min at the condition of 200-800 r/min, and filtering by using filter paper to obtain regenerated base oil;
3) the representation of the regeneration capacity of the regenerated adsorbent is completed by comparing the reduction amount of the furfural content in the base oil before and after the regeneration treatment of the adsorbent to be evaluated; namely, the larger the reduction amount of the furfural content in the oil liquid after being treated by the regenerated adsorbent to be evaluated, the better the regeneration capability of the regenerated adsorbent.
2. The method for evaluating the regeneration capability of an adsorbent for industrial lubricant oil regeneration treatment according to claim 1, characterized in that: the method for quantitatively detecting the furfural content in the oil liquid is liquid chromatography.
3. The method for evaluating the regeneration capability of an adsorbent for industrial lubricant oil regeneration treatment according to claim 1, characterized in that: the quantitative detection method for the furfural content in the oil adopts an instrument of high performance liquid chromatography.
4. The method for evaluating the regeneration capability of an adsorbent for industrial lubricant oil regeneration treatment according to claim 1, characterized in that: the base oil in the step 1) is mineral oil base oil or synthetic PAO base oil.
5. The method for evaluating the regeneration capability of an adsorbent for industrial lubricant oil regeneration treatment according to claim 1, characterized in that: the kinematic viscosity of the base oil in the step 1) at 40 ℃ is not more than 50.6mm2/s。
6. The method for evaluating the regeneration capability of an adsorbent for industrial lubricant oil regeneration treatment according to claim 1, characterized in that: and 2) the purity grade of the furfural is analytically pure.
7. The method for evaluating the regeneration capability of an adsorbent for industrial lubricant oil regeneration treatment according to claim 1, characterized in that: the regenerated adsorbent to be evaluated in the step 1) is an adsorbent which is used for removing polar aging products in oil and is regenerated by the oil, wherein the adsorbent is silica gel, diatomite, ion exchange resin, activated alumina, a silicon-aluminum adsorbent or clay.
8. The method for evaluating the regeneration capability of an adsorbent for industrial lubricant oil regeneration treatment according to claim 1, characterized in that: the filter paper in the step 2) is preferably qualitative filter paper, and the filtering speed of the filter paper is preferably medium or slow.
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| CN113073000A (en) * | 2021-03-08 | 2021-07-06 | 安徽中天石化股份有限公司 | Method for improving performance of phosphate flame-retardant hydraulic oil |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105056886A (en) * | 2015-07-29 | 2015-11-18 | 国网山东省电力公司电力科学研究院 | Absorbent for processing transformer waste oil and preparation method thereof |
| CN105866390A (en) * | 2016-06-21 | 2016-08-17 | 林光琴 | Evaluation method for insulating properties of power transformer |
| CN108998193A (en) * | 2018-07-16 | 2018-12-14 | 浙江大学 | A kind of regeneration method of waste lubricating oil |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4846962A (en) * | 1987-02-12 | 1989-07-11 | Exxon Research And Engineering Company | Removal of basic nitrogen compounds from extracted oils by use of acidic polar adsorbents and the regeneration of said adsorbents |
| CN106019091B (en) * | 2016-05-14 | 2018-11-02 | 东盟电气集团南京股份有限公司 | power system transformer performance evaluation system |
| CN106124701B (en) * | 2016-06-21 | 2018-06-26 | 王元廷 | Power transformer performance monitoring system |
| CN207423904U (en) * | 2017-11-01 | 2018-05-29 | 华电青岛发电有限公司 | Transformer oil monitors pretreatment unit on-line |
| CN110045036B (en) * | 2019-05-05 | 2022-03-25 | 西安热工研究院有限公司 | Regeneration capacity evaluation method of industrial lubricating oil regeneration adsorbent |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105056886A (en) * | 2015-07-29 | 2015-11-18 | 国网山东省电力公司电力科学研究院 | Absorbent for processing transformer waste oil and preparation method thereof |
| CN105866390A (en) * | 2016-06-21 | 2016-08-17 | 林光琴 | Evaluation method for insulating properties of power transformer |
| CN108998193A (en) * | 2018-07-16 | 2018-12-14 | 浙江大学 | A kind of regeneration method of waste lubricating oil |
Non-Patent Citations (4)
| Title |
|---|
| REGENERATION OF INSULATING MINERAL OIL BY CARBONATED AMORPHOUS CALCIUM PHOSPHATE--CHITOSAN ADSORBENT;A. C. Laurentino 等;《Process Safety and Environmental Protection》;20071231;第85卷(第B4期);第327-331页 * |
| 净油器中吸附剂对变压器油中糠醛含量的影响;李国兴 等;《全国电力用油技术学术研讨会》;20051231;第284-290页 * |
| 变压器油中固体绝缘老化分解产物的检测与研究;谭乔甜 等;《中国优秀硕士学位论文全文数据库 工程科技II辑》;20180115(第1期);第42-43页第4.2.1节 * |
| 废润滑油再生工艺的研究;李璐 等;《辽宁石油化工大学学报》;20081231;第28卷(第4期);第20-23页 * |
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