SU1239592A1 - Method of determining storage life of lubricating oil - Google Patents

Abstract

The invention relates to the field of analysis of lubricating oils and can be used to predict their shelf life. The aim of the invention is to reduce the duration of the determination and reduce the oil consumption. The method is implemented as follows. The oil sample is divided into two parts, one of which is kept in conditions of high humidity at a temperature of 97-1ОЗ С with periodic sampling until the acid number increases sharply to determine the induction period of chemical stability and to carry out a preliminary assessment of the shelf life of the oil by chemical stability according to q, p MA io 2 (c-1, p) 710 s-G, where is the induction period of chemical stability, h; t, is the oil retention temperature of 97-103 ° C; .1 p is the average annual temperature in the climatic zone of the predicted storage, C, and the second part of the oil is centrifuged and the time is set to the amount of 0.0045 - 0.0055 % and determine the shelf life of the oil based on physical stability according to: 1.14 10 F, - h / where), CR, kinematic viscosity of the oil at temperatures, respectively, centrifugation and predicted storage, mm / s, and acceptable storage time oils evaluated by the smallest of the two defined. The determination of the permissible shelf life of the oil according to the proposed method takes 15 people, days instead of 300 man-days with field tests, and is 1 month instead of 60 months. The amount of oil required to determine is significantly reduced. Table 3, 1 Il t. (O (L to QP QP SL with 1 hr

Description

 eleven

The invention relates to the field of analysis of lubricating oils and can be used to predict their shelf life.

During long-term storage, lubricating oils undergo periodic (daily and seasonal) heating and cooling due to environmental temperature fluctuations, are in contact with humidified air, etc.

Prolonged impact of these factors on lubricating oils, pred. multicomponent systems that form a basis can break their stability and lead to stratification, precipitation, hydrolysis, oxidation, etc.

In this connection, research has been constantly carried out on the experimental natural storage of oils, the purpose of which is to establish the maximum permissible storage time for them in warehouses. . .

The aim of the invention is to reduce the detection time and reduce the oil consumption.

The drawing shows a graph of the change in acid number versus test time.

The method is implemented as follows.

In laboratory conditions, the test images of the 1 oils of the VNII NP and VM-6-20 oils are divided into two parts each in quantity. 250 ml.

One part of the oil is first moistened at 20 ± 3 ° C and a relative humidity of 80% for 24 hours, then glass vials of the cherry type are filled with this oil, sealed, and filled in a thermostat at 100 + for up to 30 days. those. carried out the process of artificial aging of the oil. Every 24 hours, two ampoules are taken from a thermostat and the acid number is determined.

The measurement results in this example implementation are given in table 1.

Table

Continued table. one

According to the obtained results, the graphical dependence of the acid number on the test time is constructed and by a sharp increase in the acid number, i.e. at the inflection point, determine the Indication period tj of chemical stability (Fig. 1).

Then, according to the experimentally found mathematical dependence (Eq. 1), the permissible storage period for the oils VNIISH1 50-1-4f and VM-6-20 is determined by chemical stability

 xp

to 1 14 10

-BUT

(one)

Where. CXP - preliminary storage time - oil by chemical stability, year; e - induction period of chemical stability, h; tj - holding temperature

oils 97 - 103 ° C; - the average annual temperature in the climatic zone of the projected storage, C. The result obtained for the moderate climatic zone (10 ° C) is

for oil VNIINP 50- | -4f - 5 years (-, 86 h, t SO) for oil VM-6-20 - 40 years.

31

The second part of the tested oils is filtered through a blue filter paper with a pore size of up to 1 µm and then centrifuged in a horizontal plane with a centrifuge separation factor of 10 thousand. After every hour of centrifugation, remove one centrifugal tube, measure the oil temperature and determine the amount sediment from the oil, i.e. physical stability.

The measurement is continued until the amount of sediment is 0.005 + 0.0005%. Upon reaching a sediment value of 0.005 + 0.0005%, the centrifugation time and the oil temperature are noted. The kinematic viscosity of the oil is determined at the centrifugation temperature and the storage temperature.

The results of the measurement in this example of implementation are given in table 2.

Table 2

Missing

||.

7.0

8.0.

8.5

81

210

300

315

ii

ten

eleven

12

1, 14- F g h

 h i

 1dr

sikm alny j as ntrao i-yu

p, t li5% f5 and

awn o20

re

a 2

25

thirty

35

40

45

50

55

where is - C

"R

g,

KR

t Л tiAl t.p

2)

shelf life of oil according to physical stability, year;

centrifuge separation factor of 4-10 thousand; centrifugation time until a critical mass of precipitate is deposited equal to 0.0045-0.0055%; the kinematic viscosity of the oil at temperatures according to centrifugation and predicted storage j,

Then, according to the experimentally found dependency (equation 2), the shelf life of the tested oils is determined by physical stability: for an oil, the VNII NP 50-1-4F is 10 years old.

for butter

VM-6-202 years

Of the two mathematically determined terms of storage of lubricating oils, the shortest possible storage time for oils is the shortest. Thus, the tested oils VNIINP 50-1-4f and VM-6-20 in real conditions can be stored in a moderate climate zone for no more than 5 and 2. Years, respectively, while retaining all the necessary physicochemical and operational properties.

The results obtained correspond to the data of natural storage of these oils under real conditions: for oil, VNII NP 50-1--4F is 5 years, for VM-6-20 oil is 2 years.

The proposed method makes it possible to estimate the totality of all chemical and physical processes occurring in a multicomponent system (lubricating oil) through the formation of acidic products formed during oxidation and hydrolysis, i.e. at artificial aging of oil, and loss of a deposit at centrifuging of oil.

The method of estimating the maximum permissible storage time of an oil by chemical stability is based on one of the isothermal methods, based on the van't Goffd rule, according to. which the rate of chemical reaction increases by 2-4 times with a temperature increase of 10 ° C.

The choice of acid number of oil as a criterion. The determinative induction period of artificial aging is due to the results of oil research under actual storage conditions: the indicator most likely to change during the storage of oils is the acid value of the oil.

Physical stability characterizes the ability of an oil to preserve its original physical state during storage: do not delaminate or form a precipitate.

Oils, as complex multicomponent fine systems, occupy an intermediate position between suspensions and solutions. In the process of storage under the action of gravitational field forces, gradual sedimentation of additive particles in the form of a precipitate is possible.

The tendency of oils to precipitate or delaminate into components of the suspension, t on the nature of the base oil and additives and their quantitative ratios. In finely dispersed systems, the deposition of particles is very long, and during dissolution it may not even appear at all when the diffusion and intermolecular forces exceed the strength of the graphitational ones. the floor

Dp evidence of the effectiveness of the method (reducing the duration, reducing labor costs and oil consumption; comparative tests of the same oil VNII NP 50-1-AF were carried out using the proposed and known methods.

The conditions for determining the maximum shelf life of an oil by a known method are as follows.

The test oil VNII NP 50-1-AF in the packaging of the manufacturer (20-liter cans) in the amount of 540 kg lay on the experimental storage in three climatic zones (southern, middle and northern) of 10 .bidonov in each zone, Store t in unheated rooms. Every year storage is opened at a single bidor in each zone and analyzed according to GOST indicators and a set of methods. According to the results of the analysis, the quality of the oil and the maximum permissible storage period are judged. If the oil does not comply with the requirements of GOST for any of the indicators, it is considered inappropriate for use for its intended purpose. Maximum allowed storage time

it is set for 1 year after another check. The quality of the oil, when it turned out to be non-standard. In our example, the oil VNII NP 50-1-4F turned out to be non-standard in the sixth year of testing. The maximum shelf life of the oil is 5 years.

Table 3 presents the technical and economic characteristics of the methods for determining the maximum permissible shelf life of an oil.

Ta.litza 3

The required amount of oil, kg

1.0

540

Duration

test, month .1,060,

3Q Effort, man- days

15

300

The accuracy of determining the maximum permissible storage time of lubricating oils according to the proposed method can be evaluated when compared with the results of full-scale storage. Thus, the maximum permissible storage period for the oil of the VNII NP 50-1-4f oil in the middle climatic zone, determined by the proposed method, is 5 years. Natural storage ensures the stability of the performance properties of this oil also for 5 years. However, the determination of the maximum permissible shelf life of the oil according to the proposed method takes only 15 man-days instead of 300 man-days in full-scale storage. In addition, the determination time for the proposed method is 1 month instead of 60. months. The amount of oil required to determine is significantly reduced.

When choosing the optimal test conditions, the assumption is that the duration of determining the storage period does not exceed 1 month for all types

oils and the results obtained under optimal conditions of testing correspond to the results of natural storage, the optimal test temperature

  BUT

is 100 ° C, and a critical sediment mass is 0.005 with a separation factor

centrifuges within 4-JO thousand. At the same time, the required test duration is ensured and the results obtained correspond to the results of full-scale storage.

Determining the maximum permissible storage time for oils at temperatures below is possible in principle, however, at the same time, the process of aging will slow down considerably and the definition may be from several months to several years. .

An increase in the temperature of artificial aging above 100 ° C leads to a change in the mechanism of the oxidation process, hydrolysis and other thermal transformation and, accordingly, distorts the results of the determination of the storage period.

Centrifugation is used to speed up the process. Depositing oil from a precipitate. The centrifuge separation factor mainly determines the duration of the test in determining physical stability.

..

FORUMUA AND 3 ABOUT AND

The method for determining the shelf life of lubricating oil, including its fulfillment in the environment, periodic sampling and determination of their quality indicators,

This is done in order to reduce the duration of the test and reduce the oil consumption, the test sample of oil is divided into two parts, one of which is filled under conditions of increased humidity at 97 - with periodic sampling until a sharp increase acid number to determine the induction period of chemical stability and carry out a preliminary assessment of the shelf life of the oil by chemical stability according to

from 1.14 / 10

-four

10 ° С

where tj is the induction period of chemical stability, h; t 5 - holding temperature

oil equal to 97-103; - average annual temperature of the tour

in the climatic zone of projected storage. C, and the second part of the oil is centrifuged, the time until sedimentation (n) is fixed in the amount of 0.0045-0.0055% and the shelf life of the oil is determined by physical stability according to

tt

s; p 1.14. fb- .Pr.g

Where

FP - centering factor i,., V / t

fugues, equal to 4-10 thousand;

h. kinematic viscosity

oils at temperatures according to centrifugation and forecasted storage, MMVc, and the permissible storage period for lubricating oil are estimated from the smallest of the two specified.

I

t

I I

five

.9 t5

i.0

1.5 1.0

0.5

24

W 72 25 5

Editor V. Ivanova

Compiled by D. Ivanova

Tehred N. Bonkalo Proofreader M. Pojo

Order 3389/43 Circulation 778 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

Dyaninp oil SO l-tip

Macao VM 5-I

n / o

--- f

t t 168

Vrvny ispngani h

Claims (1)

Claim A method for determining the shelf life of lubricating oil, including maintaining it under ambient conditions, periodic sampling and determination of their quality indicators, is characterized by the fact that, in order to reduce the duration of determination and reduce oil consumption, the test oil sample is divided into two parts one of which is kept in high humidity conditions at 97 - ¹⁰³ C with periodic sampling until a sharp increase in the acid number to determine the chemical stability of the induction period and spend Pre An estimate of the shelf life of the oil in terms of chemical stability according to s' _p = 1, 14/1 (P 2, where is the induction period of chemical stability, h; t ₉ - oil holding temperature equal to 97-103 ° C; - the average annual temperature in the climatic zone of the predicted storage, ° C, and the second part of the oil is centrifuged / the time until precipitation C \) is fixed in the amount of 0.0045-0.0055% and the shelf life of the oil is determined by physical stability according to where is the separation factor center. Fugues, equal to 4-10 thousand; . .xr ~ kinematic viscosity of the oil at the temperatures of respectively centrifugation and predicted storage, mm ² / s, and the permissible shelf life of the lubricating oil is estimated from the lower of the two defined.