SU1786335A1 - Method of pipeline transporting viscous oils and oil products - Google Patents

Description

The invention relates to pipeline transport, mainly in the field of viscous and solidifying oils.

A known method of transporting viscous and solidifying oils, which consists in their preliminary heat treatment. With this method, the oil is heated to a certain temperature, then it is cooled and changes its rheological properties - yield strength, pour point and then pumped,

However, with the known method, the properties of heat-treated oils are greatly influenced by the conditions of oil cooling, the higher the ratio of the paraffin content to the content of asphalt-resinous substances in oil, the less the heat treatment effect, and finally, over time, the rheological properties of the oil — solidification temperature, yield strength, take their original meanings.

The most famous method of transporting viscous and solidifying oils is heated pumping or hot pumping,

In this method, the pumped liquid is heated at thermal stations and pumped. The distance between thermal stations is determined according to the well-known formula of V.G.Shukhov:

(L

FROM

I = bp with Ιη * ^{Т T} К K 7G O vn Г k G b (1) where B is the length of the section between the thermal stations, m; ·

About - productivity, m ³ / s;

p is the density of the pumped liquid, kg / m ³ ;

C is the specific heat, J / kg. hail; k - heat transfer coefficient, W / m ² deg;

Aries - the inner diameter of the pipeline, m; .

Tn - temperature of the beginning of pumping, ° С; ΐκ - temperature of the end of pumping, ° С; t _in - ambient temperature, ° C; those. for the implementation of the trans

It is necessary for the liquid port to operate in such a thermal regime when the final temperature of the liquid in the area between the thermal stations is greater than or at least equal to the pour point of the pumped liquid or a critical point. In addition, it must be borne in mind that planned and unscheduled shutdowns of the pipeline lasting no more than three days are possible, and at the same time, to further start the pipeline so as not to carry out additional operations (pushing liquid into barns during stops, diluting with a low-viscosity liquid, etc.), it is necessary also, withstand such a thermal regime in which the final temperature ΐκ of the liquid after three-day cooling in the area between the thermal stations is greater than or equal to the ΐ * - critical point. These measures are taken into account when arranging thermal stations.

The disadvantage of this method of transporting liquid is that taking into account the phenomenon of stopping the pipeline reduces the distance between the thermal stations and on long pipelines leads to significant capital and operating costs for the construction and operation of additional thermal stations.

The purpose of the invention is to reduce the number of thermal stations.

The goal is achieved by the fact that they carry out heating of the liquid at a thermal station, pump it to a critical point and install a throttling device at this point, which ensures throttling of the pressure with the effect of heat generation.

The essence of the method is as follows. The final temperature ΐκ (critical point) in the area between the thermal stations is determined so that it’s equal to the freezing temperature x * after the cooling process during a three-day stop. and the length of the plot is calculated according to the formula of V.G. Shukhov (1).

Then, the pressure losses R _T r are determined by the length of the calculated section using known methods (see RD 39-30-139-79 Thermal and hydraulic calculation of trunk pipelines under stationary and non-stationary modes of pumping Newtonian and non-Newtonian oils in various climatic conditions. Minneftegzzprom, VNIISPTneft Ufa, 1979, p. 55).

Given the difference between the pressure created by the pumps at the beginning of the Rnas pipeline, and the friction pressure loss P _t p in the section between the vehicle:

Rnas - Rtr - Rp · ± Δ 2 r d = Δ R, where Rnas - the maximum pressure of the pumping station;

RP - backwater in front of the pumping station;

ΛΖ - elevation difference between the beginning and the end of the pipeline section, at the end of the section (critical point) a throttling body is installed, and the temperature rises by the following amount (see RD 39-30-577-81 Methods of thermal and hydraulic calculation of pipelines during stationary pumping of Newtonian oils taking into account the heat of friction. Minnefteprom-, Tyumen branch of the Institute Giprotruboprovod, UNI, 198! p.15):

_A. 0.924 10 ~ ⁷ · γΔΡ · 0 Tdr “-” “

+ 0.403 x ^W 8,1-10 _to .stanovleniya;

0 = _100; . ,

RC - ~ Prandl criterion;

V-kinematic viscosity, m / s.

Due to the temperature obtained during the throttling process, an additional section is calculated from the critical point to the next thermal station. The length of the additional L section is determined by the well-known formula 8. G. Shukhov, where under the sign of the logarithm instead of x _n substitute instead of ΐκ + Δ Tdr. Thus, the length between stations will be.

ί + Δ ^{ί =} I — dr, where Ldr is the length of the section due to the installation of a throttling organ.

Then, according to the well-known relation to gr 5 tr _ „ί ίηρ’ where Ι_τρ is the total length of the pipeline, km; ί - length of the section without throttling, km;

1786335 6

CR - the length of the site with a throttle body, km, determine the number of reduced thermal stations.

Thus, given that they usually try to avoid throttling (see the book Tugunov P.I., Nechval M.V., Novoselov V.F., Akhatov Sh.N. Operation of main pipelines' ¹ , Bashkir book publishing house, Ufa , 1975, p. 50), in the invention, the goal is achieved by using a throttling body as a heat source to increase the distance between thermal stations, which meets the criteria of novelty and significant differences.

The proposed method of transporting liquid is most effective in the initial period of operation of the pipeline, when the pumping capacity is lower than the design capacity.

To implement the necessary thermal regime for pumping liquid through the pipeline in the initial period, it is necessary to build additional thermal stations, since the length of the pipeline section is directly proportional to the pumping capacity. When the pipeline reaches its design capacity, the required thermal regime can be achieved with fewer pumping stations. The proposed method avoids the construction of thermal plants, and with an increase in pumping capacity, throttling stops.

.Example. Initial data: En = 0.72 m - pipe diameter:

p = 840 kg / m ³ - density:

C = 2000 J / kg ° C - heat capacity; k = 0.5 W / m ² . ° С - heat transfer coefficient;

= 0.1 m ³ / s - pipeline productivity;

ΐ ₈ = -25 ° С - ambient temperature;

t'n 60 ° С - temperature of the beginning of pumping;

ΐ * = 20 ° С · - pour point; p 15 = 860 kg / m ³ - density; ν = 8.3 "10 m / s - kinematic viscosity;

En “0.14 WAl ° C - thermal conductivity coefficient;

1_tr - 300 km - the length of the pipeline; ΐκ = 44.5 ° C. - critical temperature.

1. Determine the length of the plot with the parameters ΐ _Η = 60 ° C; ΐκ = 44.5 ° C: ι = | ΐ n - g in _

ΚπϋοΗ ΐ to -ΐ _Β

0,1 · 840 · 2000, 60 +25 _

0.5 · π · 0.7 ^η 44.5 + 25 = 30000 μ - 30 km.

We determine the pressure loss in the pressure section of the section according to the methodology (see, RD 39-139-79 Methods of thermal and hydraulic calculation of main pipelines under stationary and non-stationary modes of pumping Newtonian and non-Newtonian oils in various climatic conditions. Minnefteprom,

VNIISPTneft, Ufa, 1979, SIZE program ”):

Rgr = 5 "10 ⁵ Pa (5 atm).

Considering that the strength properties of the pipeline are designed for 55 atm, and the pumps develop the same pressure, a pressure of 55 atm is created at the beginning of the pipeline, and a throttling body (for example, a valve) is installed at the thirtieth kilometer, with Δ Р = Рнас - Ртр = 50 -atm = 5.10 ⁶ Pa (for illustrative purposes, neglect the values of P _p> Δ Ζ) throttling occurs, while the temperature increases by 30 by the following value:.

0.924 -10 ⁷ · g · ΔΡ · ά

0.403 + 8.1 / 10 “ ³ ί ky = · 100 = 3.49;

grS _p 8.3 -10 ⁵ -840 -2000

P gG =

0.14

1003;

G = 1 +0.3 = 3.99;

RP-1_,, _{n п} 1003 - 1 ο /, ”ι и, ό п / _

P, t ³ 1003 ⁴³

0.924-10 ⁷ · 3.99 · 5 · 10 ⁶ · 3.49 / = 8.5 ° С.

0.403 + 8.1 -10

44.5

Given the increase in temperature by 8.5 ° C, i.e. ΐκ + Δ t _D r = 53 ° С, we calculate the length of the Additional section Δ ί to the next thermal station, fulfilling the condition that the minimum temperature in the section is not less than 44.5 ° С:

Δ b = W 1 - +. 4-A-Cr. - 1c =

KtgOvn X to ~ T about

0.1-840 -2000, 53 +25 _ ~ 0.5 · π · 0.7 44.5 +25 = 17629 ~ 17.5 km.

Thus, b _dr = B + ΔΙ = 30 + 17.5 = 47.5 km.

We determine the number of reducible thermal stations η = к! Е-Ι + β. 300 _ 300 ^P B Ιςρ 30 47.5

10-6 = 4.

If the pumping capacity O = 0.1 m ³ / s was the initial one for the pipeline under consideration, then when the pumping capacity increases to 0.16 m ³ / s, throttling stops, since the length of the section with parameters r _and = 60 and ΐκ = 44.5 according to the calculations of section 1, it will reach 47.5 km. In this case (the start of operation of the pipeline) it will not be necessary to build an additional four thermal stations.

Obviously, the use of a throttling body installed at a critical point and providing throttling with the effect of heat generation allows increasing the distance between 5 thermal stations, thereby reducing the number of thermal stations from ten to six, which leads to significant savings in capital costs.

Claims (1)

Formula of the invention 10 A method of transporting viscous oils and oil products through a pipeline, including heating oil at a heat station, creating additional pressure at the pump station and converting mechanical energy into heat energy, including by throttling, and pumping it to a critical point with a given temperature, characterized in that the additional pressure created at the pump 20 stations, transmit to critical points with a given temperature, where oil is throttled with the effect of heat generation.