RU2528462C1 - Method and apparatus for feeding paraffin inhibitor into hydrocarbon pipeline - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: in order to feed a paraffin inhibitor into a hydrocarbon pipeline, the inhibitor is mixed with a lower alcohol and then sprayed through at least one atomiser into the pipeline.

EFFECT: improved method.

11 cl

Description

The invention relates to the field of transportation of hydrocarbons by pipelines and can be used both on trunk pipelines and on pipelines of short length.

Known (SU, copyright certificate 755337) is a method for supplying a paraffin inhibitor to a hydrocarbon transportation pipeline. According to a known method, a triple copolymer of ethylene with vinyl lapetate and maleic anhydride is fed into the pipeline in an amount of 0.01-0.5%.

The known method is inefficient and expensive.

Known (SU, copyright certificate 1745744) is a method for supplying a paraffin inhibitor to a hydrocarbon transportation pipeline. According to the known method, surfactants are supplied to the pipeline, in which quality sodium dialkylbenzenesulfonate is used in an amount of at least 200 mg per liter of oil.

This method is also inefficient and did not find application in the transportation of hydrocarbons.

Known (SU, copyright certificate 1364699) is a method of inhibiting paraffin deposition in transported hydrocarbons by introducing tar into the transported hydrocarbon dissolved in gas condensate.

The known method is also ineffective.

It is known (RU, patent 2173203) the use of methanol as a complex reagent to prevent the release of hydrates and paraffins from gas condensate. Methanol is introduced into the gas condensate at the stage of preparing it for transportation.

As practice has shown, the introduction of methanol in gas condensate, and even more so in transported oil or natural gas, in relation to the inhibition of paraffin deposition does not show any effect.

Known (TU 39-1018-85) is a dosage dosing unit designed for the dosed introduction of liquid demulsifiers, as well as paraffin inhibitors, scaling, corrosion (hereinafter referred to as reagents) into the pipeline of the oilfield transport and oil preparation system for the implementation of in-line oil demulsification, and also protection of pipelines and equipment from paraffin deposition, scaling and corrosion. The known installation is equipped with a metering electric pump, a reagent tank with a volume of 225 or 450 l, an electro-contact pressure gauge, shut-off valves, a check valve, a reagent filter, a level gauge, a ruler with a division price of 1 mm for estimating the amount of liquid in the tank, and a control cabinet.

The unit is designed for dosed supply of the reagent in predetermined volumes and under a certain pressure into the pipeline, indicating the inclusion of the dosing pump and transmitting data on the status of the UDE dosing pump via communication channels.

Installation works as follows. The reagent from the tank through the valve of the level gauge and the filter enters the pump inlet through the pipeline. The pump delivers the reagent through a pipeline on which an electrical contact pressure gauge, a shut-off valve and a check valve are installed to prevent the reagent and well fluid from returning in the absence of pressure from the pump.

It was experimentally established that the introduction of any paraffin inhibitor using a known installation is ineffective, since in this case the inhibitor enters the hydrocarbon medium transported by pipeline, by stream, and the contact of the inhibitor with the hydrocarbon is negligible.

The technical result obtained by the implementation of the developed technical solution consists in increasing the inhibition of paraffin deposition in the flow of hydrocarbons transported through the pipeline.

To achieve the specified technical result, it is proposed to use the developed method of inhibitor supply. According to the developed method, a paraffin inhibitor is combined with a lower alcohol and is injected into the pipeline through at least one nozzle. The lower alcohol per se, in particular methanol, is not a paraffin deposition inhibitor and, when implementing the method, acts as a solvent / diluent for the paraffin deposition inhibitor. All currently known effective paraffin inhibitors are high viscosity liquids that cannot be introduced into the pipeline by spraying through a nozzle. The introduction of paraffin deposition inhibitors into the pipeline through the nozzle makes it possible to obtain a finely dispersed paraffin deposition inhibitor over the entire cross section of the pipeline and, accordingly, to contact the entire volume of the transported hydrocarbon with the inhibitor, thereby increasing the efficiency of paraffin deposition inhibition. The characteristics of the introduction of the inhibitor (the composition of the inhibitor, the pressure of the mixture of the paraffin inhibitor and lower alcohol, the ratio of the lower alcohol to the paraffin inhibitor, the type of lower alcohol used, the characteristics of the nozzle and the number of nozzles used) are determined by the characteristics of the pipeline, as well as the type and properties of the hydrocarbon being transported.

Preferably, methanol, ethanol, isopropanol, ethylene glycol are used to mix with the paraffin inhibitor.

Since pipelines, especially main pipelines, have a significant diameter, when implementing the method, usually two or more nozzles are used, located around the circumference of the pipeline at an equal distance from each other. In this case, nozzles are preferably placed at the edges of the pipeline, which protects them from mechanical damage from mechanical impurities moving together with the hydrocarbon through the pipeline. To increase the efficiency of introducing the inhibitor, it is preferable that the nozzles are arranged so that their longitudinal axes are set at an acute angle in the direction of flow of hydrocarbons. In this case, the orientation “upstream” or “upstream” is possible. Also, the nozzle (or nozzles) can be installed in the flow of hydrocarbons along the axis of the pipeline "upstream" or "upstream".

In a preferred embodiment, depending on various conditions, the paraffin inhibitor is combined with a lower alcohol in a ratio of from 3% to 97%.

In the case of using a paraffin inhibitor with a very high viscosity, the inhibitor can be heated. Preferably, the inhibitor is heated to the stage of combining it with a lower alcohol.

It is also proposed to use the developed paraffin deposition inhibitor feed device to achieve the indicated technical result. The developed device for introducing a paraffin inhibitor contains a line - a source of lower alcohol, on which the first control valve is installed, a line - a source of a paraffin inhibitor, on which a second control valve is installed, a tee, to the inputs of which these lines are connected, the output of the tee is connected to at least the entrance of one nozzle, the nozzle of which is discharged into the hydrocarbon transportation pipeline.

The developed device provides controlled, through the use of valves, the supply of both components of the mixture (a paraffin inhibitor and lower alcohol) introduced into the pipeline, the use of a tee that acts as a mixer / connector of two liquids, combining them into a single composition, the nozzle inlet and the nozzle inlet through the nozzle into the pipeline.

In the case of using pipelines of significant diameter, the outlet of the tee is connected to the inlets of two or more nozzles that are led into the pipeline transporting hydrocarbons, preferably at an equal distance from each other.

Usually the longitudinal axis of the nozzle is located at an acute angle (not more than 45 °) to the axis of the pipeline.

The device may further comprise a heating unit for a viscous inhibitor, preferably located in front of the tee.

The developed device operates as follows.

Previously, on the model hydrocarbon transportation system, the desired type of inhibitor and lower alcohol, the amount of mixture per unit volume of transported hydrocarbon, the ratio of inhibitor and lower alcohol, the number of nozzles, their characteristics, and the location of the nozzles are determined.

The required number of nozzles with pre-selected characteristics is placed in the pipeline, orienting them relative to the flow in an optimal way for a particular case. The nozzles of the tee are connected to the nozzles, the low alcohol supply lines and the paraffin inhibitor are connected to the tee inputs. The action of control valves establish the necessary ratio of lower alcohol and paraffin inhibitor, as well as their total consumption.

The developed technical solution is further illustrated by an example.

For the main pipeline with a diameter of 1420 mm, the inhibitor SNPCH-IPG-11 (TU 2458-179-057670-2009) was chosen as a paraffin inhibitor. Isopropanol was used as the lower alcohol at a ratio of paraffin deposition inhibitor: isopropanol = 1: 10. The mixture was fed into the transported oil from 4 nozzles located at an equal distance from each other around the circumference of the pipeline. The nozzles were oriented according to the flow of transported oil.

When applying an inhibitor mixed with isopropanol in an amount of 100 g of inhibitor per ton of oil, the efficiency of the method, determined by the “cold rod” method, was approximately 62-69%.

The developed method can be applied to pipelines corrosion inhibitors, paraffin waxes, anticoagulants, antifoams, detergents, etc.

Claims (11)

1. A method for supplying a paraffin inhibitor to a hydrocarbon transport pipeline, characterized in that the paraffin inhibitor is combined with a lower alcohol and is injected into the pipeline through at least one nozzle. 2. The method according to claim 1, characterized in that methanol, ethanol, isopropanol, ethylene glycol are used. 3. The method according to claim 1, characterized in that at least two nozzles are used, the longitudinal axes of which are installed at an acute angle in the direction of hydrocarbon flow. 4. The method according to claim 1, characterized in that the paraffin inhibitor is combined with lower alcohol in a ratio of from 3% to 97%. 5. The method according to claim 1, characterized in that the inhibitor is heated before connecting with a lower alcohol. 6. A paraffin inhibitor supply device to the hydrocarbon transport pipeline, characterized in that it contains a main line - a source of lower alcohol on which the first control valve is installed, a main line - a source of a paraffin inhibitor, on which a second control valve is installed, a tee, to the inputs of which are indicated the line, the outlet of the tee is connected at least to the inlet of one nozzle, the nozzle of which is brought out into the hydrocarbon transportation pipeline. 7. The device according to claim 6, characterized in that the outlet of the tee is connected at least to the inputs of two nozzles, the outputs of which are brought into the pipeline for transporting hydrocarbons at an equal distance from each other. 8. The device according to claim 6, characterized in that the longitudinal axis of the nozzle is located at an acute angle to the axis of the pipeline. 9. The device according to claim 6, characterized in that the longitudinal axis of the nozzle is located at an angle not exceeding 45 ° from the axis of the pipeline. 10. The device according to claim 6, characterized in that it further comprises an inhibitor heating unit. 11. The device according to claim 6, characterized in that the longitudinal axis of the nozzle is located along the axis of the pipeline.