RU2470213C1 - Method of processing high-viscosity and waxy oil for pipeline transportation - Google Patents

Abstract

FIELD: oil-and-gas industry.

SUBSTANCE: invention relates to transportation of oil and oil products. High-viscosity and waxy oils are prepared for pipeline transportation by adding hydrocarbon diluter thereto. Note here that said diluter represents the product of 340-540°C oil fraction thermolysis extracted in heated oil fractionation. Note here that cuts with initial boiling point of -340° and >540°C produced in fractionation are combined with thermolysis product to cool the mix produced and to stabilise it with extraction of stabilisation gas and prepared oil. Note also that thermolysis is performed at 450-520°C and 0.4-2.5 MPa for 0.1-0.5 h.

EFFECT: higher process efficiency.

1 cl, 1 dwg

Description

The invention relates to the transport of oil and oil products and can be used to improve the preparation for pipeline transport of high-viscosity and paraffinic oils by reducing their viscosity.

A known method of preparing high viscosity and paraffin oils for pipeline transport, which consists in the fact that when transporting oil into the pumped oil, hydrocarbon diluents are introduced [Gubin EV, Gubin VV "Pipeline transport of oil and oil products." - Nedra, 1982, p. 157].

The disadvantage of this method is the use of expensive and scarce diluents.

Closest to the claimed is a method of preparing highly viscous and paraffinic oils for pipeline transport, which consists in introducing hydrocarbon diluents into highly viscous and paraffin oil, which are used, in particular, a liquid product of the processing of associated petroleum gases (a mixture of light aromatic hydrocarbons, mainly benzene, toluene and xylene) in the transport of oil in an amount of 1-20%. Liquid products are obtained on zeolite-containing catalysts at 600-650 ° C, a volumetric feed rate (mixture of C ₂ -C ₄ hydrocarbons) of 90-220 h ^-1 and atmospheric pressure. [RF patent No. 2089778, Cl. F17D 1/16, publ. September 10, 1997].

The disadvantage of this method is its low efficiency when used in real fishing conditions:

- due to the impossibility of obtaining a sufficient amount of hydrocarbon diluent due, as a rule, to the limited resource of associated petroleum gas (5-15% wt. per oil) and the insignificant yield of a liquid product of its processing (20-35% wt.), resulting in a potentially the achieved amount of diluent is only 1-5% of the mass. and, accordingly, the viscosity and pour point of the oil are reduced slightly;

- the known method only slightly reduces the content of solid paraffins in oil, causing its high viscosity and pour point, and reduces them only due to dilution with a liquid product, and therefore cannot be used to reduce the viscosity of paraffinic oils, since the prepared oil is in accordance with GOST R 51858-2002 should contain no more than 6% of the mass. paraffins;

- upon receipt of a liquid diluent product in the method according to the prototype, 65-80% of the mass is formed as a by-product. non-condensable low pressure hydrocarbon gases requiring further disposal;

- the method requires significant energy costs for the preparation of raw materials, namely for the allocation of fractions C ₂ -C ₄ from associated petroleum gas, and for heating the raw material to 600-650 ° C.

EFFECT: increased efficiency of the process of preparing highly viscous, both paraffinic and / or resinous, oil by reducing viscosity, pour point of oil, and also the content of solid paraffins by isolating solid paraffins from oil and converting them into a liquid product used to dilute oil .

The specified technical result is achieved by the fact that in the known method of preparing highly viscous and paraffinic oils for pipeline transport by introducing a hydrocarbon diluent into the transported oil, the peculiarity is that the liquid product of thermolysis of the oil fraction 340-540 ° C, isolated during the fractionation of heated oil, while the fraction of NK -340 ° C and> 540 ° C obtained by fractionation of oil, combined with the product of thermolysis, the resulting mixture is cooled and stabilized with evolution of stabilization gas, and thermolysis is carried out at 450-520 ° C, pressure 0.4-2.5 MPa within 0.1-0.5 hours.

The selection of the oil fraction of 340-540 ° C during the fractionation of heated oil containing the bulk of solid paraffins, its thermolysis with the destruction of solid paraffins to obtain a low molecular weight, low viscosity and low solidification liquid product, and the use of this product as a diluent leads to a multiple decrease in the viscosity and pour point of oil due to a significant reduction in the content of solid paraffins in oil due to their destruction, as well as due to dilution of the oil with the resulting product. As an additional effect, an improvement in the quality of oil in terms of the "paraffin content" indicator is achieved.

The method is as follows (a process diagram is shown in the drawing).

The original oil (stream I) preheated in a heat exchanger 1 to a temperature of 200-250 ° C, is subjected to fractionation in a fractionating apparatus 2 with the separation of the fraction 340-540 ° C (II), which is heated in the furnace 3 to 450-520 ° C and subjected thermolysis in thermolysis apparatus 4 at 450-520 ° C, pressure 0.4-2.5 MPa for 0.1-0.5 hours. Obtained by fractionation of heated oil fractions n.k. -340 ° C (III) and> 540 ° C (IV) are combined with the thermolysis product (V), the resulting mixture (VI) is cooled in heat exchanger 1, stabilized in stabilization apparatus 5 with evolution of stabilization gas (VII), which is disposed of together associated petroleum gas, and prepared oil (VIII), which is transported to the consumer.

Examples of the method

Example 1

To prepare for the transport of pipelines high viscosity paraffin Uzen oil with a design viscosity at 20 ° C of 360 cSt, pour point + 33 ° C and a solid paraffin content of 14.2% by weight, oil preheated in heat exchanger 1 to a temperature of 250 ° C is subjected fractionation in fractionation apparatus 2 with the release of 35% of the mass. fractions 340-540 ° C, which is heated to 480 ° C and subjected to thermolysis in a thermolysis apparatus 3 at a pressure of 0.8 MPa for 0.2 hours. Fractions n.k. -340 and> 540 ° C obtained by fractionation of oil, combined with the product of thermolysis, the mixture is cooled and stabilized to obtain 1.4% of the mass. stabilization gas and 98.6% of the mass. prepared oil with a viscosity of 14.5 cSt, pour point minus 3 ° C and a paraffin content of 2.4% by weight.

Example 2

To prepare for the transport of pipelines high viscosity resinous Karazhanbass oil with a viscosity at 20 ° C of 920 cSt, a pour point of minus 26 ° C and a solid paraffin content of 1.5 wt%, oil preheated in heat exchanger 1 to a temperature of 280 ° C is subjected to fractionation in fractionation apparatus 2 with the release of 32% of the mass. fractions 340-540 ° C, which is heated to 450 ° C and subjected to thermolysis in a thermolysis apparatus 3 at a pressure of 0.4 MPa for 0.1 hour. Fractions n.k. -340 and> 540 ° C, obtained by fractionation of oil, combined with the product of thermolysis, the mixture is cooled and stabilized in yield to obtain 1.1% of the mass. stabilization gas and 98.9% of the mass. prepared oil with a viscosity of 53 cSt, pour point + 1 ° C and a solid paraffin content of 0.4% by weight.

Example 3

To prepare high-viscosity paraffin Gerasimov oil with a viscosity at 20 ° C 28 cSt, pour point minus 6 ° C and a solid paraffin content of 4.0 wt%, pipeline oil preheated in heat exchanger 1 to a temperature of 220 ° C is fractionated in fractionation apparatus 2 with the release of 42% of the mass. fractions 340-540 ° C, which is heated to 520 ° C and subjected to thermolysis in a thermolysis apparatus 3 at a pressure of 2.5 MPa for 0.1 hour. Fractions n.k. -340 and> 540 ° C obtained by fractionation of oil, combined with the product of thermolysis, the mixture is cooled and stabilized in yield, obtaining 2.5% of the mass. stabilization gas and 97.5% of the mass. prepared oil with a viscosity of 11 cSt, pour point minus 15 ° C and a solid paraffin content of 0.5% by weight.

Example 4

Under the conditions of example 3, the fraction 340-540 ° C is heated to 450 ° C and subjected to thermolysis at a pressure of 1.2 MPa for 0.5 hours, obtaining 2.1% of stabilization gas and 97.9% of the mass. prepared oil with a viscosity of 9 cSt, pour point minus 13 ° C and a solid paraffin content of 0.2% by weight.

These examples are summarized in table.

From the table it follows that the process at 450-520 ° C, a pressure of 0.4-2.5 MPa for 0.1-0.5 can reduce the viscosity of oil by 7-25 times, lower the pour point by 5-36 ° C, to provide a paraffin content below the normalized value of 6% of the mass. The achieved performance indicators of the oil preparation process significantly exceed the performance of the prototype.

The proposed method for the preparation of highly viscous and paraffinic oils for pipeline transport finds industrial application at many oil production facilities in the Russian Federation.

Table Characteristic Oil Uzen Karazhanbass Gerasimovskaya According to the prototype Example one 2 3 four Crude oil Viscosity at 20 ° С, cSt 360 ¹ 920 28 28 Pour point, ° C 33 -26 -6 -6 The content of paraffins,% wt. 14.2 1,5 4.0 - Process parameters Temperature ° C 480 450 520 450 600-650 Pressure, MPa 0.8 0.4 2.5 1,2 0.1 The duration of the process, h 0.2 0.1 0.1 0.5 0.011-0.005 The amount of diluent,% wt. 35 32 42 42 5 Oil prepared Viscosity 14.5 53 eleven 9 21.9 Pour point, ° C -3 <-35 <-35 <-35 -8 The content of paraffins,% wt. 2,4 0.4 0.5 0.2 -

Claims (1)

A method of preparing highly viscous and paraffinic oils for pipeline transport by introducing a hydrocarbon diluent into the transported oil, characterized in that the thermolysis product of the oil fraction is 340-540 ° C, isolated by fractionation of heated oil, the fraction of n.k. -340 and> 540 ° C, obtained by fractionation of oil, combined with the thermolysis product, the resulting mixture is cooled and stabilized with the release of stabilization gas and prepared oil, and thermolysis is carried out at 450-520 ° C, pressure 0.4-2.5 MPa within 0.1-0.5 hours

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