SU1257517A1 - Method of determining the thermooxidizing stability of fuel - Google Patents

Abstract

The invention relates to the study of motor fuels, in particular, to a method for determining their thermal-oxidative stability. In order to increase the reliability of the determination and reduce its time, the determination is carried out by adding to the test fuel when it is pumped through a heated control element of 2.5–3% by volume of the test fuel, which is a mixture of the test fuel from 0.8–1.0 wt.% dinitroso-N, N-didecyl-n-enylenediamine, and the time of entry of the control fuel is chosen while maintaining the temperature at the outlet of the refrigerator constant for 3-4 hours from the start of determination. The method allows to obtain more reliable results in a shorter period of time. 3 tab., 2 Il. Q SL Is9 SP m

Description

The invention relates to the study of motor, in particular re; active, fuels, and can be used in

petrochemical, automotive and aviation pro1-a. scale to determine the thermal-oxidative stability (TOC) properties of fuels.

The purpose of the invention is to increase the reliability of the definitions of TOC fuels and reduce the time of determination.

FIG. 1 shows a schematic of a device for determining TOC fuels; in fig. 2 is a graph explaining the definition of TOC and monitoring the correct operation of the installation.

The device (Fig. 1) contains a pre-filtering system 1 and a TonjoiBa filling station, including a filling tank 2, a jet 3, a fuel pre-filter 4. The device includes a compensation tank 5 with regard to the pressure gauge 6, the housing 7, consisting of a lifting pipe 8 with a plug 9 and a heater 10, an ice cold 11, a control filter 12 and connecting pipes - the top 13 and the bottom 14, fitting 15, located: on pipe 14, containing: check valve 1pan 16 and syringe 17, thermocouples 18 and 19, filling and drain valves 20 and 21.

The TOC of the fuel is determined as follows.

The device is assembled according to FIG. 1. In the filling tank 2 pour the test fuel, while the plug 9, the compensation tank 5, the gauge assembly 6 and the syringe 17 are not installed. The valve 20 is opened by adjusting the filling rate of the device with fuel so that it does not get into the test filter 12 through the riser pipe 8 before the refrigerator 11 and the test filter unit are filled, otherwise an air bubble may remain under the filter, preventing fuel circulation. After the device is filled with fuel, a compensating tank 5 is installed, a plug 9, refueling the device, and a gauge assembly is installed.

An electrical voltage is supplied to the heater, adjusting it so that the fuel temperature at the control filter t | reached a predetermined time (for example, 180 ° C in 20 minutes), and

12575172

set temperature during the test. At the same time, a certain temperature is automatically set at the exit from the refrigerator, the value of which depends on the density of the fuel. If the fuel has a high TOC, the control filter remains clean, the degree of circulation does not change and tj remains unchanged for 3-4 hours. If TOC is low, then the control filter is clogged with sediment formed during oxidation of the fuel with oxygen dissolved in the fuel and in the gas phase.

5 compensation tank. Wherein

the hydraulic resistance of the line increases and the degree of fuel circulation decreases, it cools in the refrigerator, as evidenced by a decrease in the outlet temperature

t (see Fig. 2). With respect to him

initial value at the moment of entering the mode corresponds to driving

 control filter 12 to 80%. Fridge refrigerator t live t-, on

life t,

thirty

35

40

45

50

55

at

const also indicates the circulation of fuel in the installation and thus the correctness of its operation. In this case, special control over the operation of the device is not required. The absence of change 12 (which may mean either high TOC of the fuel — the filter remains clean, or cessation of the fuel circulation, i.e. incorrect operation of the device) leads to a decrease in the reliability of the TOC determination, and in operation to allow unstable fuel to be used on the equipment, including aviation. In the absence of a change in t within 3-4 hours of work from the start of testing, it is allowed to fluctuate by 1-2 C during this time, which can be associated with a change in ambient temperature (without stopping the test, it is proposed to apply special monitoring for the correct operation of the device) . The essence of this control is that, in the absence of a change in tj within 3-4 hours or the cessation of its change, the previously prepared control fuel, which is a mixture of the test fuel and 0.8-1.0% of the additive XT-5, is introduced into the working yc-j - capacity is 2.5-3.0 of the total amount of fuel, and tj remains unchanged for 3-4 hours. If TOC is low, then the control filter is clogged with sediment formed during oxidation of the fuel with oxygen dissolved in the fuel and in the gas phase.

5 compensation tank. Wherein

the hydraulic resistance of the line increases and the degree of fuel circulation decreases, it cools in the refrigerator, as evidenced by a decrease in the outlet temperature

t (see Fig. 2). With respect to him

initial value at the moment of entering the mode corresponds to driving

 control filter 12 to 80%. Fridge refrigerator t live t-, on

life t,

at

const witness

It also concerns the presence of fuel circulation in the installation and thus the correctness of its operation. In this case, special control over the operation of the device is not required. The absence of change 12 (which may mean either high TOC of the fuel — the filter remains clean, or cessation of the fuel circulation, i.e. incorrect operation of the device) leads to a decrease in the reliability of the TOC determination, and in operation to allow unstable fuel to be used on the equipment, including aviation. In the absence of a change in t within 3-4 hours of work from the start of testing, it is allowed to fluctuate by 1-2 C during this time, which can be associated with a change in ambient temperature (without stopping the test, it is proposed to apply special monitoring for the correct operation of the device) . The essence of this control is that, in the absence of a change in tj within 3-4 hours or the cessation of its change, the previously prepared control fuel, which is a mixture of the test fuel and 0.8-1.0% of the additive XT-5, is introduced into The working yc-j is 2.5-3.0% of the total amount of fuel through a medical syringe 17, the cone of which is hermetically attached to the internal cone of the check valve 16 (Fig. 1). If after some time the temperature tj starts to decrease (for example, 1-2 ° C per minute), then it can be concluded that the device is working properly (see Fig. 2, cr. 3).

To prove the effectiveness of the proposed method, comparative tests were carried out to determine the TOC by the proposed method and the prototype method (see Table 1). The evaluation of TOC was carried out according to the driving speed of the filter W, characterized by the ratio of the temperature change at the outlet temperature from the refrigerator to the time of this temperature change, W, ° C / hour.

From tab. 1 it can be seen that when testing the fuels with the prototype method on individual fuel samples, there is a probability () of their circulation in the device, which reduces the reliability of the results, requires a large number of consecutive determinations (at least 5) and therefore check the correct operation of the device.

The results of research on the effect on TOC of fuel estimated by the rate of change of tg, the amount of control fuel and the content of XT-5 additives in it (s 3 h, t:, 180 c / W u ti / t,; C / h)

From the data table. 2, it follows that the optimal concentration of the XT-5 additive for preparing the reference fuel is 0.8-1.0%, and the optimum amount of the reference fuel introduced into the device is 2.5-3.0%, since the rate of temperature change

s

About 5

0 5

0

about

five

on the code from the refrigerator (W) at these ratios is maximum. Thus, the TOC determination time is significantly reduced.

In order to justify the introduction of control fuel, research was also conducted, the results of which are shown in Table 3.

From the data of table 3 it follows that the reliability of the results of the TOC assessment is shown by 3 hours of testing and practically not. changes after 4 h.

Thus, the proposed method makes it possible to reduce the determination time at the control verification stage (after entering the control fuel), reduce the number of determinations of the thermo-oxidative stability of the fuels, and increase their reliability.

Claims (1)

Invention Formula The method for determining the thermo-oxidative stability of the fuel, including pumping it through a heated control element and a refrigerator with an assessment of the stability of the fuel based on the rate of temperature change at the exit from the refrigerator, is due to the fact that, in order to increase the reliability of the determination and reduce its time, the process is carried out with the addition of 2.5–3 vol.% of the control fuel, which is a mixture of the fuel under study with 0.8–1.0 wt.% dipitroso-K, K-didecyl-n-phenylenediamine, to the test fuel. , etc Why the time of entry of the control fuel is chosen when the temperature at the exit from the refrigerator is kept constant for 3-4 hours from the beginning of the determination. n) a s c; YU rt H with; you nj f01 X (U about tt o l g 01 “Oh .. Z (bi o (Tp, t 0) oo. Svo fM go II P uh oh eight n to P S x table 2 tf c with PP g G7 t ,, C 180 BSof then t / 6th C / Chry / / WITH 234 gflfM t. Editor A. Dolinich Compiled by N. Bogdanova Tehred L.Oleynik Proofreader M. Demchik Order A910 / 41 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