RU2525052C1 - Preparation of high-viscosity oil and associated oil gas for pipeline transportation - Google Patents

Abstract

FIELD: oil-and-gas industry.

SUBSTANCE: proposed method comprises oil heating in recuperative heat exchanger, addition of the product of oil thermolysis at 340-540°C as a diluent mixed low-boiling fractions -340°C and >540°C obtained at oil fractionation. Mix cooling and stabilisation are performed with extraction of stabilisation gas and prepared oil. Note here that thermolysis is executed with production of vapours and liquid residue used as process fuel for auxiliaries. Oil fractionation is performed in the mix with thermolysis vapours. At fractionation, fractionation gas is released and mixed with stabilisation gas, associated oil gas and subjected to catalytic cyclodehydrogenation. Product of the latter is mixed with low-boiling fraction -340°C and subjected to catalytic hydration with production of gas and liquid product. The latter is mixed with fraction >540°C, cooled down in recuperative heat exchanger and directed for stabilisation. Gas is cleaned of acid components and dried to get dry stripped gas and acid gas derived from the plant.

EFFECT: higher quality and yield, recovery of associated oil gas.

2 cl, 1 dwg

Description

The invention relates to the transport of oil and gas and can be used to prepare for the transport of pipelines of high viscosity and paraffin oils by reducing the viscosity of the oil and at the same time processing associated petroleum gas to produce marketable dry stripped gas and oil component.

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. The method does not provide for the simultaneous processing of associated petroleum gas.

A known method of preparing high-viscosity and paraffinic oils for pipeline transport is that hydrocarbon diluents are introduced into high-viscosity and paraffinic oil, in particular, the liquid product of the processing of catalytic dehydrocyclodimerization of associated petroleum gas (a mixture of light aromatic hydrocarbons) is introduced into the amount of 1-20% vol.

The disadvantage of this method is its low efficiency when used in real fishing conditions. Firstly, 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% by weight for oil) and the insignificant yield of the liquid product of its processing (20-35% by weight), resulting in a potentially achievable amount of diluent is only 1-5% of the mass. and, accordingly, the viscosity and pour point of the oil decreases slightly. Secondly, the known method reduces the content of solid paraffins in oil, which determines its high viscosity and pour point, 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.

Closest to the claimed is a method of preparing for pipeline transport of high viscosity and paraffin oils [RF Patent No. 2470213, publ. December 20, 2012, IPC F17D 1/16], including introducing into the oil as a diluent the product of thermolysis of the oil fraction 340-540 ° C, mixed with fractions n.k. -340 ° C and> 540 ° C obtained by fractionation of oil, cooling and stabilization of the mixture with the release of stabilization gas and prepared oil.

The disadvantage of this method is the low quality due to the presence of olefins in the hydrocarbon diluent obtained by thermolysis, as well as the loss of oil due to the formation of thermolysis gas removed in the stabilization gas, and insufficiently high yield of prepared oil. In addition, the known method for the preparation of oil does not provide for the simultaneous processing of associated petroleum gas.

The objective of the invention is to increase the yield and quality of the prepared oil, the processing of associated petroleum gas in the process of oil preparation.

The technical result that can be achieved by implementing the proposed method:

- increasing the yield of prepared oil by processing a mixture of hydrocarbon gases and possibly other light fractions by catalytic dehydrocyclodimerization to obtain an additional amount of oil component,

- Utilization of associated petroleum gas through its catalytic dehydrocyclodimerization.

The specified technical result is achieved by the fact that in the known method, including heating the oil in a recovery heat exchanger, introducing into the oil as a diluent the product of thermolysis of the oil fraction 340-540 ° C, mixed with fractions N. to. -340 ° C and> 540 ° C obtained by fractionation of oil, cooling and stabilization of the mixture with the release of stabilization gas and prepared oil, the peculiarity is that thermolysis is carried out to produce vapors and liquid residue, which is used as a process fuel for own needs oil fractionation is carried out in a mixture with thermolysis vapors; fractionation gas additionally emits fractionation gas, which is mixed with stabilization gas, associated petroleum gas and subjected to catalytic dehydro cyclodimerization, the product of which is mixed with a fraction of N. to. -340 ° C and subjected to catalytic hydrogenation, to obtain a gas and a liquid product, which is mixed with a fraction> 540 ° C, cooled in a recovery heat exchanger and sent to stabilization, and the gas is purified from acidic components and dried to obtain a dry stripped gas and acid gas output from the installation.

In addition to associated petroleum gas, fractionation gas and stabilization gas, any hydrocarbon mixture containing predominantly C ₃ -C ₄ hydrocarbons, for example, condensate from a complex gas treatment unit, condensate deethanization gas, etc., can be additionally directed for dehydrocyclodimerization together with associated petroleum gas, fractionation gas, and stabilization gas. allows you to dispose of these by-products in commercial conditions with the receipt of an additional quantity of marketable products.

The catalytic dehydrocyclodimerization of a mixture of stabilization gas, fractionation gas, associated petroleum gas, and / or another hydrocarbon mixture containing predominantly C ₃ -C ₄ hydrocarbons makes it possible to utilize the resulting mixture to obtain a product containing non-condensable gases, including hydrogen, and additional the amount of oil component (C ₅₊ hydrocarbons), thereby increasing the yield of prepared oil.

Catalytic hydrogenation of a mixture of a catalytic dehydrocyclodimerization product with a n.c. -340 ° C allows you to convert unsaturated hydrocarbons contained in the thermolysis product into saturated ones by catalytic hydrogenation with hydrogen contained in the catalytic dehydrocyclodimerization product, thereby improving the quality of the prepared oil.

Purification of the catalytic hydrogenation gas from acidic components and its drying allows to obtain commercial dry stripped gas and acid gas, which can be disposed of in a known manner.

The method is as follows. Crude oil (I), preheated in a recovery heat exchanger 1, is fractionated in a mixture with thermolysis vapors (II) on fractionation unit 2 to produce gas (III), fractions 340-540 ° C (IV), fractions n.a. -340 ° C (V) and> 540 ° C (VI). Fractionation gas (III) is mixed with stabilization gas (VII), associated petroleum gas and, if necessary, with another hydrocarbon mixture containing predominantly C ₃ -C ₄ (VIII) hydrocarbons — shown in dashed lines, then on block 3 is subjected to catalytic dehydrocyclodimerization to obtain a hydrogen-containing product (IX). The fraction 340-540 ° C (IV) on block 4 is subjected to thermolysis to obtain vapors (II) and the remainder of thermolysis (X) used as a process fuel. Fraction N.K. -340 ° C (V) is mixed with the product of catalytic dehydrocyclodimerization (IX) and, under block 5, is subjected to catalytic hydrogenation to obtain a liquid product (XI) and gas (XII), which are purified from acid gases and dried on block 6 to obtain a commodity dry dry gas (XIII) and acid gas (XI) processed in a known manner. The liquid catalytic hydrogenation product (XI) is mixed with a fraction> 540 ° C (VI), cooled in a recovery heat exchanger 1, and stabilized on block 7 to produce stabilization gas (VII) and prepared oil (XV) with a reduced viscosity and pour point.

The performance of the proposed method is illustrated by the following example. Example. Oil with a density at 20 ° C of 840 kg / m ³ , pour point + 27 ° C and a solid paraffin content of 20.2%, a sulfur content of 0.08% (only 100%, hereinafter% wt.) Is heated with the products of preparation to 250 ° C and fractionated in a mixture with 62% thermolysis vapors to obtain 3.5% gas, 65% of the mass. fractions 340-540 ° C, 71.5% fractions n.a. -340 ° C and 22% fractions> 540 ° C.

The fraction 340-540 ° C is subjected to thermolysis to obtain 62% of the vapor and 3% of the remainder of thermolysis, which is used as fuel for own needs. The fractionation gas is mixed with 1.4% stabilization gas and 7.6% of the compress obtained from the associated petroleum gas compression and subjected to catalytic dehydrocyclodimerization, the product of which containing 0.3% hydrogen is mixed with the NK fraction. -340 ° C and subjected to catalytic hydrogenation to obtain 5.3% gas and 78.7% liquid product.

The gas is purified from hydrogen sulfide, drained, and 0.02% acid gas and 4.98% dry stripped commercial gas are obtained. The liquid product is mixed with a fraction> 540 ° C, cooled and stabilized, to obtain 1.4% of the mass. stabilization gas and 100.7% of the mass. prepared oil with a viscosity of 14.5 cSt, pour point minus 3 ° C, with a paraffin content of 2.4% and an olefin content of less than 0.5%.

From the example it follows that the proposed method allows to increase the yield and quality of the prepared oil, to utilize associated petroleum gas in the process of oil preparation and can be used in the oil and gas industry.

Claims (2)

1. A method of preparing high-viscosity oil and associated petroleum gas for pipeline transport, including heating the oil in a heat recovery heat exchanger, introducing into the oil as a diluent the thermolysis product of the oil fraction 340-540 ° C mixed with fractions n.k. -340 ° C and> 540 ° C obtained by fractionation of oil, cooling and stabilization of the mixture with the release of stabilization gas and prepared oil, characterized in that thermolysis is carried out to obtain vapors and liquid residue, which is used as a process fuel for own needs, oil fractionation is carried out in a mixture with thermolysis vapors; fractionation gas additionally emits fractionation gas, which is mixed with stabilization gas, associated petroleum gas and subjected to catalytic dehydrocyclodi erizatsii, the product which is mixed with a fraction of X.I. -340 ° C and subjected to catalytic hydrogenation, to obtain a gas and a liquid product, which is mixed with a fraction> 540 ° C, cooled in a recovery heat exchanger and sent to stabilization, and the gas is purified from acidic components and dried to obtain a dry stripped gas and acid gas output from the installation. 2. The method according to claim 1, characterized in that the dehydrocyclodimerization together with associated petroleum gas, fractionation gas and stabilization gas additionally serves any hydrocarbon mixture containing mainly C ₃ -C ₄ hydrocarbons.

Images