DE2039329A1 - Process to improve the transportability of paraffin-rich crude oils - Google Patents

Description

Patent assessor Homberg, July 30, 1970

Dr. G. Schupfner T 70 022

Deutsche Erdöl AG (D 70.973) 4102 Homberg / Ndrh.
Baumstrasse 31

TEXACO DEVELOPMENT CORPORATION

135 East 42nd Street New York, N.Y. 10017

UNITED STATES.

Process to improve the transportability of paraf-

fin-rich crude oils

The invention relates to a method for improving the Flow properties of crude petroleum, which have high pour points and have a high paraffin content.

The extraction of paraffin-rich crude oils is likely to increase significantly in the next few years. Lots of these crude oils are beneficial because of their low sulfur content because they have little or no hydrogenation treatment for the production of middle distillates and heating oil with a low risk of air pollution require. Since the air pollution caused by the combustion of sulfur-containing heating oils, Increased importance in both the United States and Western Europe is the increased extraction of paraffinic crude oils with a low sulfur content are very desirable.

Unfortunately, however, the handling and transportation of these paraffin-rich crudes can be difficult because of their relatively high levels Pour points especially in geographical areas with cold

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Weather can lead to difficulties. Many of these paraffin-rich crude oils for example, have pour points in the range of about -1 10 bis, O ⁰ C or higher. This temperature range is commonly encountered during cold weather in much of the United States and Western Europe. In the cold seasons there is always the possibility that the flow of crude oil in pipelines and storage facilities is impaired. Not only can the transport of these crude oils be interrupted, but considerable expenditure of time, labor, and money is required to restore the normal flow properties of these crude oils. To solve these costly and troublesome handling and transportation problems, it is essential to keep the pour point of these paraffin-rich crudes at about -1. ⁰ C or below.

The following three methods are essentially used to lower the pour points of paraffin-rich crude oils:

1. Dilute the crude oil with a suitable cutter fluid with a low pour point.

2. Mixing the crude oil with other crude oils that have a much lower pour point.

J>. Distillation and solvent dewaxing.

It has been found, however, that none of these known methods are entirely satisfactory. The dilution of paraffin-rich crude oils with extenders, for example, requires the addition of the same with up to 50 % of the crude oil volume. Not only is this costly, but the large amount of co-solvent also decreases the amount of crude oil you get. can pump through a pipeline. Furthermore, for economic reasons, the diluent must be grown back. However, due in turn relatively expensive recovery methods such as distillation and the shipment of large volumes requires extenders to ¹ I ^ Iz zsur crude source. Mixing the paraffin-rich crudes with other low-pour point crudes can also cause difficulties, especially

_3-203S329

when the low-stock crude oils are used in large proportions. For example, many of the crude oils which have sufficiently low pour points for mixing, relatively high sulfur contents. This will however the advantage of the low-sulfur crude oil with a high pour point is negated because the crude oil mixture has a relatively high Has sulfur content. Since you have to add up to 70% by volume of the crude oil that is rich in paraffin, the volume of paraffin-rich crude oil that can be transported is significantly reduced. After all, that's with associated with a solvent dewaxing treatment Distillation is not only expensive but also reduces the product yield. Purely the large amounts of paraffin obtained are created In addition, there is a considerable storage and recycling problem.

In view of the disadvantages of the known methods, there is one Need for a viable, relatively inexpensive way of reducing the pour point of high-paraffin wax Crude oils without reducing the yield of the products obtainable therefrom.

It has now been found that the pour point can be made more paraffin-containing Surprisingly, mild heat treatment can reduce crude oils considerably. This heat treatment can be done with carry out the currently used processing plants without the disadvantages of the known methods described and in many cases also has the advantage that the yield increases in the more popular middle distillates.

The invention relates to a method for improving the transportability of paraffin-rich crude oils with a pour point of about -1 to 30 ° C or higher, characterized in that the crude oil under a pressure of slightly below atmospheric pressure up to about 176 atü is enough, heated to a temperature of around 300- - 650 ° C until its "pour point" is considerably reduced. A first embodiment of the method of the invention provides a paraffin-rich crude oil with an initial pour ρ ο ir t of

about -1 to 30.4 ⁰ G under a pressure that ranges from slightly below atmospheric pressure to about 176 atü to a temperature of about 340 - 65O ⁰ C until the pour point is considerably reduced and an easier handling and transportable crude oil is produced.

In a second embodiment of the invention, a paraffin-rich crude oil which has a pour point of -1 to 16 ⁰ G or higher is to be heated to a temperature of 371-538 ° C. for 1 to 120 minutes under a pressure of 0-53 atmospheres until the pour point has dropped ^{to at least below I 0 C.}

In the preferred embodiment of the invention, a 1-10 paraffinreiches.Rohöl, which originally has a viscosity of less than about 300 centistokes at 50 ° C and an initial pour point of about -1.11 to 4.44 ⁰ C or higher, minutes under a pressure of 17.6 to 52.7 atm at a temperature of 399 - 538 ⁰ C heated until no significant changes in viscosity or boiling range of the crude oil to be Pour point has dropped below approximately -3.89 ° C.

For a better understanding of the invention, the following are intended Terms are explained in more detail:

A) Transportability. The invention is based on the fact that the transport, pumping, mixing and handling of certain paraffin-rich crude oils can be improved by a mild heat treatment which lowers the pour point without a simultaneous reduction in viscosity or a change in the boiling point distribution. This improvement in properties is commonly referred to as portability. In order to improve the transportability, it is necessary to lower the pour point considerably. As a considerable reduction is here a reduction of about 50% for crude oils which have a pour point of 4.44 - 29.4 ⁰ C own or a decrease by at least 25% in the crude oils whose anfäng-

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2033329

Licher pour point is around -1.11-4.44 ° C. The pour point should preferably even be reduced to -3 »89 ^° C. or below.

B) Paraffin content. The invention relates to the treatment of crude oils with a high initial paraffin content. Since the paraffin content of a given crude oil can vary considerably depending on the method of determination used, other features are used here to identify crude oil substrates which are suitable for the treatment according to the invention, namely their viscosities and pour points. The crude oils by the process of the invention to be treated are initially viscosities below about 300 centistokes at 50 ⁰ O, and a pour point of about 1.1 - 29.4 ° C or possess higher. This is an indirect but more convenient way of designating the properties of the crude oils accessible to the process of the invention.

G) Types of paraffin-rich crude oils. The usable paraffin-rich crude oils should have a viscosity below about 300 centistokes at 50 ⁰ C, and a pour point of about 1.11 -

² J- ⁰ C. These crude oils should preferably be low in sulfur, ie contain about 0.05-1.0% by weight of sulfur. These crude oils are preferred because they are available in large quantities and can be refined cheaply into low-sulfur heating oils.

D) The plant. The mild heat treatment carried out according to the Invention to improve the transportability of paraffin-rich Crude oils is required, does not require any special facility. Rather, each can be directly heated Use a heating system that consists of a combustion chamber surrounded by pipes through which the oil flows and absorbs the heat generated in the combustion chamber by both radiation and convection. Examples of this "' are large boiler systems with separate parts for rising or falling convection currents. Such-

ge heating systems are in the technical as well as 3? at ent liberator adequately described, e.g. in the "Petroleum Processing Handbook", Part 4, edited by Bland and Davidson, McGraw-Hill Verlag, 1967. To increase the residence time, one can use a direct-heated boiler also connect to a storage tank ("soaking drum").

E) Reaction conditions:

1. The G limits of the working temperature are between about 343 - 64-9, preferably 399 - 538 ⁰ G.

2. The pressure can vary from slightly untartialb of atmospheric pressure move up to 176 atmospheres, with a range between atmospheric pressure and about 52.7 atmospheres preferred will. Since heating costs decrease when a high proportion of the crude oil remains in the liquid state, will a pressure range of 17.6-52.7 atmospheres is particularly preferred.

3. Response time. Depending on the nature of the crude oil being treated, the heating temperature and the pressure used, the reaction time can vary from a fraction of a second (0.1 sec.) To 50 hours. An advantageous range of the reaction time is about 1 for 120 minutes when a typical crude oil having a pour point of -1.11 - 29.4 ⁰ C in the preferred temperature and pressure is heated areas. The preferred reaction time is about 1-10 minutes.

The following examples illustrate the method of the invention further explained. Unless otherwise stated, parts and percentages are by weight.

1Ö9S19 / 1692

Example 1: Mild heat treatment of an Orito crude oil

In this example, two samples of a crude oil-Columbian Orito, originally, a kinematic viscosity of 4.77 Gentistokes at 50 ° C, a sulfur content of 0.5% wt., And a pour point of 4.44 ⁰ C has, in a customary spiral test cracking system under the conditions given in Table 1 for tests no. 9285 A and 9286 C. The properties of the two hollow oils treated according to the invention are compared with those of the untreated original (virgin) hollow oil. The values shown in Table 1 show a considerable reduction in the pour point of the treated oil compared to the untreated, and this pour point reduction is maintained even after three months of storage. In addition, the yields of the more popular middle distillates are higher in the case of the heat-treated crude oils. There was no significant change in viscosity.

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Table 1 Orito crude oil

Reaction conditions

Untreated trial run Trial run original No. 9285 A No. 9286 C crude oil

Feed rate, g / h

Boiler pressure, atm

Boiler temperature, C

Response time, minutes

3350 3010 24.6 24.6 480 498.5 2.0 2.2

Yield, wt% of fresh feed

Gas, total 0.7 0.4 0.7 Naphtha,
Bp 46.1-121.1 ° C 18.1 18.1 18.6 Light gas oil,
B.p. 177-343 ° C 35.5 55.6 55.9 Residue,
343 ^O C 47.9 45.9 44.8 Visibility, cSt at 50 ° C 4.77 4.55 5.58 at 98.9 ° C 2.08 2.07 1.77 Pour point, ⁰ G

of the entire liquid product

After 3 months of storage

4.44

-28.9
-28.9

-37.2 -57.2

10 9 819/1692

Example 2; Mild heat treatment of a Pennington crude

In this example, a sample was a Nigerian Pennington crude oil, which initially has a viscosity of 2.7 cSt at 50 ⁰ C, a sulfur content of 0.07 wt.%, And a pour point of 12.8 ° C had, in a conventional spiral -Cracking test facility heated under the conditions given in Table 2 for test No. 9289 B. As in Example 1, the pour point of the treated crude oil was lowered considerably (compared to the untreated crude oil) without the viscosity having changed significantly.

Reaction conditions

Table 2 Pennington crude

Uri treated

original

Pennington crude

Experiment No. 9289 B

Feed rate, g / h

Boiler pressure, a tu boiler temperature.

⁰ C

Response time, min.

Yield, wt%

the fresh Beschik kung

of the entire liquid product

Stable pour point

12.8
12.8

3054 3.52

482.5 2.2

Initial boiling point -177 ° C 17.9 17.1 Light gas oil,
Bp. 177-343 C 55.7 54.6 Residue 343 ⁰ C 26.4 28.3 Viscosity, cSt at 50 ⁰ C
at 98.9 ⁰ C 2.7
1.35 2.54
1.28 Pour point, ⁰ C.

-9.44; -6.67 1.67; 1.67

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Example 3 ' - Mild Heat Treatment of Amna Crude Oil

In this example, a sample was a Libyan Amna-crude oil (Experiment Nr.9288 G), which initially has a viscosity of 11.5 cSt at% 50 ⁰ O, a sulfur content of 0.17 wt., And a pour point of 21.1 ⁰ G, heated in a customary spiral grack test facility under the conditions given in Table 3 for test no. 9288 G. WMerum the pour point of the treated crude oil was significantly lower than that of the untreated crude oil. In this case stepped

__. of viscosity ₃ __, _ _ ,, .._,.,. "a decrease" in the treated crude oil (compared to the untreated) and a corresponding shift in the boiling range distribution of the treated crude oil was observed. The yields of the more valued middle distillate were increased.

Reaction conditions

Feed rate, g / h

Boiler pressure, atm

Boiler temperature, - Response time, min. - Yield, wt %
the fresh delivery
kunp; Initial boiling point -177 ° C 16.3 Light gas oil,
Kp. 177-343 ⁰ C. 26.6 Residue 34-3 ° C 57.1 Viscosity, cSt at 50 ° C
at 98.9 ° C 11.5
2.8 Pour point, ⁰ C. of the entire year
sigprodukts 21.1 Stable pour point 21.1

Table 3 Attempt no
9288 G Amna - crude oil 6181 Untreated
original
Amna crude oil 3.52 - 4-70.5
7.3 - -

15.6

33.5 50.9

, 7 2.1

-6.67 -6.67

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Example 4;

In this example, a sample of a crude oil-Amna denoted by test 9403 "which point a Sehwefelgehalt% of 0.17 wt., And a pour of 21 'was 1 ⁰ C, under the conditions shown in Table 4 Working conditions in a Eesselanlage The properties of the heated crude oil were compared with untreated original (virgin) crude oil. The values in the table confirm not only that the desired substantial reduction in the pour point has occurred, but also that it was maintained during three months of storage remains and that the yields of the more popular middle distillates are increased by the method of the invention.

Table 4 Experiment # 9403
Amna Sohöl Amna - crude oil Conditions of Action Untreated
Amna-Hohöl Atmospheric pressure Loading speed
speed, g / h - 385 Pressure, atü - 6 hours Temperature, ⁰ C - reaction time - 36.9 Physical.Constants -12.2 Density, ⁰ API 35.2 - 9.44 Pour point, C. 21.1 Stable pour point, ⁰ C 21.1 17.2 Yield, wt.% Of
fresh loading 33.9 Initial boiling point -177 ° C 16.3 48.9 177-343 ° C 26.6 343 ° C + 57.1

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Example 5:

Comparative- In this example, the pour point of the Amna crude oil is from Example 3 by blending with high sulfur crude from low pour point.

In this example, the untreated Amna crude oil is owned by Example 3 ", the point a pour of 21.1 ⁰ C, mixed with an Arabian crude oil a pour point of -28.9 ° C and a sulfur content of 1.6 wt .% possesses in order to investigate the influence of the already mentioned mixing process on the reduction of the pour point to an acceptable level. The values reported in Table 5 show that this mixing process is relatively ineffective. As can be seen from this, for example, 70% by volume of the Arabian crude oil must be mixed with 30% by volume of the untreated Amna crude oil in order to achieve a pour point that is even half acceptable. This greatly reduces the amount of paraffin-rich Amna crude that can be transported, and the sulfur content of the blend is considerably greater than the initial sulfur content of the Amna crude. These? significant increases in sulfur content is particularly undesirable as it results in the production of middle distillate fuel oils and residual oils which contribute to air pollution.

- 13 109819/1692

- 13 Table 5

Composition of the crude oil mixture% by volume

Pour point wt.% S.

Untreated Ainna Eoh Oil

100 90 80 70 60 50 40 30 20 10 0

Arabic
crude oil

0 10 20 30 40 50 60 70 80 90 100

21.1 0.17 17.8 0.33 12.8 0.46 10.0 0.60 10.0 0.74 4.44 0.89 1.67 1.03 -1.11 1.17 -3.89 1.31 13.3 1.46 28.9 1.60

Example 6;

Comparative- In this «example the pour point of the Amna crude oil is taken from Example 3 reduced with the aid of diluents.

An attempt should be made to lower the pour point of the Amna crude oil from Example 3 to below -1.1 ° C. with various co-solvents. The following table 5 shows that it is possible to add up to 45 vol.% Of various cosolvents, without achieving the desired reduction of pour point, even when the co-solvent have pour points from -160 ⁰ C.

- 14 -

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- 14 Table 5a

Blending agent Leichtes "FC" - light ison-butane

Cycle "straight pentane gas oil run"

naphtha

Pour point, C.

Vol .-% extender

10 14 15 20 25 29 35 40 4-5

-26.1

-98.84 '-160 -138.2

Pour points of the mixture, C

21.1

12.8 7.22

21.1 21.1 - 23.9 23.9 21.1 18.3 18.3 18.3 18.3 18.3 18.3 12.8 12 ₁ 8 4.44 4.44

21.1

21.1

As can be seen from the above description and examples, the method according to the invention is useful in various respects advantageous. The process offers, for example, an inexpensive method to improve the transportability of crude oils, which have both a high paraffin content and high pour points, without the previously known, relatively expensive ones Mixing, distillation and dilution processes must be used. The method of the invention can be also using those found in petroleum processing and common equipment. The process of the invention also does not require solvents recover and for the paraffin neither storage nor To accept sales problems. Finally, according to the new process, crude oils rich in paraffin, the high pour point and possess low sulfur content for making

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of middle distillate fuel oils that use their combustion only makes a negligible contribution to air pollution. In contrast, the known mixing process, although it improves the pour point, increases the risk of air pollution the paraffin-rich crude oils because they have to be mixed The crude oils used have a significantly higher sulfur content.

The method of the invention also accomplishes an important one and bring about unexpected result compared to the already known mild heat treatments of residual oils. To that extent namely, when, according to the method of the invention, a substantial reduction in the pour point of the total crude oil is obtained without significantly affecting the viscosity of the treated crude oil at the same time. In contrast to causes the already known mild heat treatment of Residue oils significantly reduce both the pour point and the viscosity. As "was already mentioned, However, for some purposes, such as the production of lubricating oils, it is the retention of the original viscosity of the treated crude oil is very desirable.

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Claims (4)

- 16 - T 70 patent claims 1. A method for improving the transportability of paraffin-rich crude oils with a pour point of about -1 to 30 ⁰ C or higher, characterized in that the crude oil is under a pressure that ranges from slightly below atmospheric pressure to about 176 atmospheres, 650 ⁰ C heated until its "Pour point" has decreased significantly - to a temperature of about the 340th 2. The method according to claim 1, characterized in that the crude oil to about 370-540 ⁰ C is heated. 3. Process according to Claim 1 or 2, characterized in that the heat treatment reduces the pour point of the crude oil to below about -I ⁰ C. 4. The method according to claim 1-3 »characterized in that a crude oil, the high paraffin content, a sulfur content of about 0.05-1.0% by weight, a viscosity of less than 300 centistokes at 50 ⁰ C and a pour point has from about -1 to 10 ⁰ C, - heating 54O ⁰ C, said boiling point and viscosity of the crude oil substantially "unchanged äeiben - under a pressure of about 17-53 atmospheres gauge to a temperature of about the 400th 5. The method according to claims 1-4, characterized in that an Amna, Orito or Pennington crude oil with an initial pour point of about -I ⁰ C to 15.6; -1 to 10 ⁰ C or -1 to 4.44 ⁰ C, is assumed. 109819/1692 COPY