阅读说明：本技术 一种评价清净剂的碱值保持性的方法 (Method for evaluating base number retention of detergent ) 是由 冯涛 翟月奎 袁学军 王海峰 于 2018-06-26 设计创作，主要内容包括：本发明提供了一种评价清净剂的碱值保持性的方法,该方法包括以下步骤：按清净剂碱值,取一定量清净剂加入到基础油HVI400SN中,调制TBN15～50mg KOH/g的油品。将硫酸(33％m/m)与冰醋酸(纯)按1：3调制成混合酸备用。取上述混合酸2～8mL加入到上述80～100g的润滑油样品中,于60-65℃搅拌100～120分钟后,停止反应,并进行碱值、酸值检测。通过碱值、酸值的判定,可以判定出清净剂的碱值保持性差异。本发明所提供的方法简单易行,检测结论可作为润滑油研制人员选定清净剂的依据,同时可作为清净剂生产人员生产性能优异清净剂的依据。(The invention provides a method for evaluating the base number retention of a detergent, which comprises the following steps: adding a certain amount of detergent into base oil HVI400SN according to the base number of the detergent, and preparing an oil product with TBN 15-50 mg KOH/g. Sulfuric acid (33% m/m) and glacial acetic acid (neat) were mixed in 1: 3, preparing the mixed acid for standby. And adding 2-8 mL of the mixed acid into the 80-100 g of the lubricating oil sample, stirring at 60-65 ℃ for 100-120 minutes, stopping reaction, and detecting the base number and the acid number. The difference in the retention of the base number of the detergent can be determined by determining the base number and the acid number. The method provided by the invention is simple and feasible, and the detection conclusion can be used as the basis for selecting the detergent by lubricating oil developers and can be used as the basis for producing the detergent with excellent production performance by detergent producers.)

1. A method for evaluating the base number retention of a detergent, comprising the steps of:

step 1, adding a detergent into base oil to prepare an oil product with a total base number of 15-50 mg KOH/g, wherein the detergent is an alkylbenzene sulfonate detergent, a sulfurized alkylphenate detergent or an alkyl salicylate detergent;

step 2, mixing 25-33% m/m sulfuric acid and pure glacial acetic acid according to a mass ratio of 1: 1-1: 3, blending into mixed acid for standby;

step 3, adding 2-8 mL of the mixed acid prepared in the step 2 into 80-100 g of the oil product with the total base number of 15-50 mg KOH/g prepared in the step 1, stirring at 60-65 ℃ for 100-120 minutes, stopping reaction, and detecting the base number and the acid number;

and 4, judging the base number retentivity of the detergent according to the detection results of the base number and the acid value, wherein the judgment standard is as follows: base number change rate ═ (initial base number-final base number)/initial base number 100%;

for alkyl benzene sulfonate detergents:

when the initial base number of the detergent is less than 300mg KOH/g, if the base number change rate is less than 26 percent and the final detected acid value is less than the volume of the added acid, the base number retention is better in the range;

when the initial base number of the detergent is more than 300mg KOH/g, if the base number change rate is less than 20 percent and the final detected acid value is less than the volume of the added acid, the base number retention is better in the range;

for sulfurized alkylphenate detergents:

if the change rate of the base number is less than 33 percent and the final detection acid number is less than the volume of the added acid, the base number retention is better in the range;

for alkyl salicylate detergents:

if the rate of change in the base number is less than 36% and the final measured acid number is less than the volume of acid added, this indicates that the base number retention is good in this range.

2. A method of assessing the base number retention of a detergent as claimed in claim 1, characterised in that the alkylbenzene sulphonate detergent has an initial base number greater than 290mg KOH/g.

3. A method of assessing the base number retention of a detergent as claimed in claim 1, characterised in that the initial base number of the sulphurised alkylphenate detergent is greater than 240mg KOH/g.

4. A method of assessing the base number retention of a detergent as claimed in claim 1, characterised in that the initial base number of the alkyl salicylate detergent is greater than 240mg KOH/g.

5. A method of assessing the base number retention of a detergent as claimed in claim 1, characterised in that in step 1 the base oil is HVI400 SN.

6. A method of assessing the base number retention of a detergent as claimed in claim 1, characterised in that in step 3 the mixed acid is added to the oil within 30 minutes.

7. The method of evaluating the base number retention of a detergent according to claim 1, wherein the method of base number test in step 3 is SH/T0521.

8. A method of assessing the base number retention of a detergent as claimed in claim 1, characterised in that the method of acid number testing in step 3 is GB/T7304.

Technical Field

The invention relates to the field of marine lubricating oil detergents, and particularly discloses a method for evaluating the base number retention of a marine detergent.

Background

Detergents are the most important additives in marine lubricating oil, and consist of surfactants and internally-wrapped inorganic salts, and the most important function of detergents is to neutralize acidic substances converted from sulfur contained in fuel. The speed of neutralizing the acidic substances determines the quality of the acidic resistance of the detergent applied to the internal combustion engine oil, and can be used as a main judgment basis for preparing internal combustion engine oil products.

The detergent is divided into sulfonate, sulfurized alkylphenate and salicylate detergents according to the types of surfactants, wherein the sulfonate detergent is the most commonly used detergent with the largest dosage, the sulfurized alkylphenate detergent is the detergent with certain extreme pressure anti-wear performance, and the alkyl salicylate detergent is widely applied to the formula of the novel marine medium-speed engine oil due to the excellent detergent dispersing performance

The surfactant in the detergent has a great influence on the performance of the lubricating oil product, and particularly in the marine lubricating oil product, the surfactant in the sulfonate detergent partially determines the anti-rusting property, the anti-emulsifying property and the water-splitting property of the product.

The core part of the detergent, i.e. the part containing inorganic calcium carbonate, calcium hydroxide, calcium oxide, etc., determines the difference in acid neutralization rate and base number retention of the detergent. Different detergents have different detergent particle sizes and different inherent inorganic compound components due to different production processes during production, so that the base number retention of the detergent particles in the specific use of the detergent particles in the preparation of a finished marine oil product is greatly different.

For a four-stroke medium-speed engine for a ship, medium-speed engine oil used by the four-stroke medium-speed engine is recycled in the engine for a long time, and a main index for measuring whether the oil is due to oil change is to measure the base number of the medium-speed engine oil. The base number of the marine oil product is determined, on the one hand, by its detergent itself; on the other hand, by the sulfur content of the fuel used. For fuels with a high sulfur content, the medium speed engine oil used therein will decrease due to a higher sulfur content resulting in a faster consumption, while for fuels with a lower sulfur content, the possibility of a decrease in the base number during use will be slower. Thus, in the formulation of different marine oil products, different detergent products are used whose base number decreases after a long period of use compared to the newly added oil by an amount that is strongly related to the sulphur content of the fuel used and the type of detergent used. Generally, according to the requirement of engine manufacturers, when the base number of the used oil reaches half of the original new base number, the limit of oil replacement is reached, and the lubricating oil needs to be replaced according to the regulation.

Therefore, the retention of the base number of the detergent is a very important technical index for marine four-stroke engine oil, has good base number retention, can ensure that the base number of the engine oil is still maintained at a high level after the engine oil is used for a long time, is beneficial to saving the oil change cost, reduces the extra workload brought by oil change, can bring direct economic benefits to lubricating oil users, and the saved time cost has good indirect benefits.

It is known that the marine medium speed engine oil equipped with a wet oil pan is usually supplied in an amount of 500 to 800 liters per one time, and when a heavy residual oil having a fuel sulfur content of 1.5% is used, the base number is usually reduced to half of that of the new oil in about 2000 hours. And if the oil is changed completely at this moment, on one hand, the shipowner needs to bear the economic loss caused by scrapping old oil in the engine, and on the other hand, the shipboard crew will spend great labor to discharge the old oil, and arrange new oil to fill up simultaneously, and in addition, the discharged old oil needs to be reasonably processed to bring extra cost to the shipowner. If the oil product with better base number retention is used, the service life of the oil product can be effectively prolonged to about 2500 hours under the same operation working condition, the original four oil change periods can be basically maintained in three oil change periods when the oil product with better base number retention is used, so that not only is the cost input of new oil reduced by one oil change period reduced, but also the convenience is brought when old oil is treated, drained and filled with the new oil.

Therefore, in the actual production process, the detergent product with better base number retention is selected for producing the medium-speed marine engine oil, and the advantages are obvious. And the proper method is selected to directly detect the base number retentivity of the detergent product, so that the method has very strong economic benefit, and the proper detection method can improve the product quality of the lubricating oil and bring great convenience.

Currently, there is no direct method for evaluating the base number retention of detergents. In the development of medium speed marine oils, detergents are generally selected based on experience, price, quality, etc., and are generally not considered to have a significant impact on key properties of the marine oil product, such as base number retention. In contrast, the base number retention of marine medium speed engine oils is a very critical indicator of marine oil. In the operation and production at the present stage, the difference of the base number retentivity of the medium-speed engine oil for the ship is generally only detected by the initial and final base numbers, and is used as a judgment whether the base number retentivity reaches the oil change standard or not, and no direct correlation exists in the base number retentivity.

In view of the key role of the base number retention to the marine medium-speed engine oil, in the development process of the marine medium-speed engine oil product, a method for evaluating the base number retention performance needs to be established, and a perfect method can provide favorable conditions for improving the quality of the marine medium-speed engine oil product.

Disclosure of Invention

The invention aims to provide a method for evaluating the base number retention of a detergent, which aims to overcome the defect that the prior art has no direct method for evaluating the base number retention of the detergent.

To achieve the above object, the present invention provides a method for evaluating base number retention of a detergent, comprising the steps of:

step 1, adding a detergent into base oil to prepare an oil product with a total base number of 15-50 mg KOH/g, wherein the detergent is an alkylbenzene sulfonate detergent, a sulfurized alkylphenate detergent or an alkyl salicylate detergent;

step 2, mixing 25-33% m/m sulfuric acid and pure glacial acetic acid according to a mass ratio of 1: 1-1: 3, blending into mixed acid for standby;

step 3, adding 2-8 mL of the mixed acid prepared in the step 2 into 80-100 g of the oil product with the total base number of 15-50 mg KOH/g prepared in the step 1, stirring at 60-65 ℃ for 100-120 minutes, stopping reaction, and detecting the base number and the acid number;

and 4, judging the base number retentivity of the detergent according to the detection results of the base number and the acid value, wherein the judgment standard is as follows: base number change rate ═ (initial base number-final base number)/initial base number 100%;

for alkyl benzene sulfonate detergents:

when the initial base number of the detergent is less than 300mg KOH/g, if the base number change rate is less than 26 percent and the final detected acid value is less than the volume of the added acid, the base number retention is better in the range;

when the initial base number of the detergent is more than 300mg KOH/g, if the base number change rate is less than 20 percent and the final detected acid value is less than the volume of the added acid, the base number retention is better in the range;

for sulfurized alkylphenate detergents:

if the change rate of the base number is less than 33 percent and the final detection acid number is less than the volume of the added acid, the base number retention is better in the range;

for alkyl salicylate detergents:

if the rate of change in the base number is less than 36% and the final measured acid number is less than the volume of acid added, this indicates that the base number retention is good in this range.

The method for evaluating the base number retention of the detergent is characterized in that the initial base number of the alkylbenzene sulfonate detergent is larger than 290mg KOH/g, and if the initial base number is smaller than the initial base number, the base number change rate is larger, so that the base number retention is inaccurate to measure, and the method is not suitable for the measuring method.

The method for evaluating the base number retention of the detergent is characterized in that the initial base number of the sulfurized alkylphenol salt detergent is more than 240mg KOH/g, and if the initial base number is less than the initial base number, the base number change rate is large, so that the base number retention is not accurately measured, and the method is not suitable for the measuring method.

The method for evaluating the base number retention of the detergent is characterized in that the initial base number of the alkyl salicylate detergent is more than 240mg KOH/g, and if the initial base number is less than the initial base number, the base number change rate is large, so that the base number retention is inaccurate to measure, and the method is not suitable for the measuring method.

The method for evaluating the base number retention of the detergent is characterized in that the base oil in the step 1 is HVI400 SN.

The method for evaluating the base number retention of the detergent is characterized in that the mixed acid is added into an oil product within 30 minutes in the step 3.

The method for evaluating the base number retention of the detergent is disclosed in the invention, wherein the method for testing the base number in the step 3 is SH/T0521.

The method for evaluating the base number retention of the detergent is disclosed in the invention, wherein the method for testing the acid number in the step 3 is GB/T7304.

The method for evaluating the base number retention of the detergent is characterized in that the base number is selected to be adjusted within the range of 15-50 mg KOH/g, preferably 30mg KOH/g, and the method is favorable for complete reaction with an acidic substance.

The method for evaluating the base number retention of the detergent is characterized in that the detergent is prepared in specific base oil, a mixture of specific base numbers is formed, an acidic substance is added at the same time, acid neutralization is carried out at specific temperature and time, and the residual base number and acid number of the whole reaction system are measured. The difference in the base number retention performance of the detergent is determined by determining the remaining base number and acid number.

The base oil used in the invention is one of the main raw materials for preparing the marine medium-speed engine oil, and the prepared target base number is the base number range most commonly used by the medium-speed engine oil. The added acid substances, namely sulfuric acid and glacial acetic acid, are acid substances which are easily generated when a ship engine runs, wherein the sulfuric acid is generated by the reaction of sulfur oxides generated during the combustion of sulfur in fuel in water, and the glacial acetic acid is generated by the oxidation of organic substances of lubricating oil at high temperature and high pressure. The method can effectively measure the base number retentivity of the detergent, and provides a certain basis for selecting the marine medium-speed engine oil detergent and improving the performance of the detergent in a detergent production plant.

The invention has the beneficial effects that:

compared with the prior art, the method provided by the invention has the following advantages:

1. the evaluation method of the invention evaluates the conclusion of the base number retention of the detergent, is beneficial to screening the base number retention of the detergent by a lubricating oil product developer, simplifies the product formula design process and improves the product formula design success rate.

2. The evaluation method of the invention evaluates the base number retention of the detergent, is beneficial to additive companies to develop detergent products with excellent performance in a targeted manner, and improves the performance of the additive.

3. The method of the invention has wide application range, is suitable for different types of detergents, and can be used for alkyl benzene sulfonate, sulfurized alkyl phenate and alkyl salicylate.

4. The method has the characteristics of simple operation, easy realization of evaluation means, rapid evaluation of the base number retentivity of the detergent, and guarantee of rapid and effective evaluation.

5. The raw materials related by the invention are easy to obtain, and the used base oil, the additive and the acidic substance are common and easy-to-obtain experimental raw materials, thereby being beneficial to the development of experimental work.

Drawings

FIG. 1 is a process flow diagram of the method of evaluating the base number retention of a detergent of the present invention.

Detailed Description

The invention provides a method for evaluating the base number retention of a detergent, which comprises the following steps:

step 1, adding a detergent into base oil to prepare an oil product with a total base number of 15-50 mg KOH/g, wherein the detergent is an alkylbenzene sulfonate detergent, a sulfurized alkylphenate detergent or an alkyl salicylate detergent;

step 2, mixing 25-33% m/m sulfuric acid and pure glacial acetic acid according to a mass ratio of 1: 1-1: 3, blending into mixed acid for standby;

step 3, adding 2-8 mL of the mixed acid prepared in the step 2 into 80-100 g of the oil product with the total base number of 15-50 mg KOH/g prepared in the step 1, stirring at 60-65 ℃ for 100-120 minutes, stopping reaction, and detecting the base number and the acid number;

and 4, judging the base number retentivity of the detergent according to the detection results of the base number and the acid value, wherein the judgment standard is as follows: base number change rate ═ (initial base number-final base number)/initial base number 100%;

for alkyl benzene sulfonate detergents:

when the initial base number of the detergent is less than 300mg KOH/g, if the base number change rate is less than 26 percent and the final detected acid value is less than the volume of the added acid, the base number retention is better in the range;

when the initial base number of the detergent is more than 300mg KOH/g, if the base number change rate is less than 20 percent and the final detected acid value is less than the volume of the added acid, the base number retention is better in the range;

for sulfurized alkylphenate detergents:

if the change rate of the base number is less than 33 percent and the final detection acid number is less than the volume of the added acid, the base number retention is better in the range;

for alkyl salicylate detergents:

if the rate of change in the base number is less than 36% and the final measured acid number is less than the volume of acid added, this indicates that the base number retention is good in this range.

The method for evaluating the base number retention of the detergent is characterized in that the base number of the alkylbenzene sulfonate detergent is more than 290mg KOH/g.

The method for evaluating the base number retention of the detergent is characterized in that the base number of the sulfurized alkylphenol salt detergent is more than 240mg KOH/g.

The method for evaluating the base number retention of the detergent is characterized in that the base number of the alkyl salicylate detergent is more than 240mg KOH/g.

The method for evaluating the base number retention of the detergent is characterized in that the base oil in the step 1 is HVI400 SN.

The method for evaluating the base number retention of the detergent is characterized in that the mixed acid is added into an oil product within 30 minutes in the step 3.

The method for evaluating the base number retention of the detergent is disclosed in the invention, wherein the method for testing the base number in the step 3 is SH/T0521.

The method for evaluating the base number retention of the detergent is disclosed in the invention, wherein the method for testing the acid number in the step 3 is GB/T7304.

The present invention will now be described in detail with reference to the following examples for better understanding of the technical features, objects and advantages of the present invention, but the present invention should not be construed as being limited to the scope of the present invention.