RU2559383C1 - Hydrate formation inhibitor supply device - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: device contains the housing, input and output branch pipes for inhibitor supply, the filter installed in the inhibitor supply line, preferably downstream the input branch pipe, the inhibitor flowmeter, the inhibitor flow rate control device. The inhibitor flow rate control device contains the housing with input and output unions and the working body inside the housing. The device is connected to the inhibitor flowmeter, while the working body of the inhibitor flow rate control device is implemented in the form of plunger pair. The piston of the named pair is implemented in the form of the cylinder able to back and forth motion by means of the electric drive. The external surface of the named cylinder has the radial grooves and, at least, one longitudinal groove with variable, preferably, triangular cross section. The through passage area of the longitudinal groove decreases from peripheral part of the cylinder towards its central part. Cavities of the named grooves are interconnected among themselves.

EFFECT: inhibitor flow rate control with pre-set accuracy in all operating modes.

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Description

The invention relates to the gas industry, and in particular to systems for introducing inhibitory substances into pipelines, and can be used to create devices for inhibiting the formation of gas hydrates in a pipeline used for transporting gaseous hydrocarbons.

The task of regulating the supply of inhibitors for the gas industry has become especially urgent at the present time, when it was time to exploit the "old" gas condensate fields, such as Urengoyskoye, Yamburgskoye, which have developed their potential by 60-70 percent. The gas wells of these fields are more susceptible to flooding of the bottom-hole zone and to moisture transfer to the gas gathering network than in the newly developed ones. In this case, the gas temperature decreases, which leads to the formation of hydrates in the wells, in the gas gathering network of the field, plumes and technological devices. The gas hydrate mode during field operation is one of the most negative phenomena causing emergency situations at gas pipelines and wells. This, in turn, requires the use of various measures to prevent hydrate formation, one of which is the introduction of an inhibitor into gas streams.

The inhibition process consists in supplying an inhibitor through a special pipeline network to the protected sections of gas pipelines, which can be produced in various ways.

A known system for supplying methanol to a pipeline containing a methanol supply line on which a first control valve is installed, up to a control valve, a methanol supply line contains two connection pipes, to each of which a first shut-off valve, a filter and a second shut-off valve are connected in series, the outputs of the second shut-off valves are connected to the input of the metering diaphragm, the output of which is connected by means of a second control valve to the input of the non-return valve, the output of which is connected through a lock ny valves to the inputs of the nozzles (patent RU No. 2413900).

A disadvantage of the known system should be recognized as the absence of a relationship between the amount of methanol introduced and the humidity of the hydrocarbon gas transported through the pipeline, which can lead to both excessive methanol consumption and the formation of gas hydrate in the pipeline due to the lack of methanol.

A known system for supplying hydrate inhibitors to a natural gas pipeline containing an inhibitor source line, two nozzles connected to the specified line, each of which is connected in series with a first shut-off valve, a filter and a second shut-off valve, the outputs of the second shut-off valves are connected to the input of the inhibitor flow sensor the output of which is connected to the inlet of the non-return valve, the output of which is connected through shut-off valves with actuators to the inputs of the nozzles, while the system further comprises a control unit and at least one of the sensors of pressure, temperature, flow, moisture content and the amount of condensate per unit volume of gas installed on the pipeline, connected to the input of the control unit, the outputs of the control unit are connected to the actuators of the stopcocks, and the control unit is made with the possibility, depending on the measured parameters of the transported gas, to establish the optimal flow rate of the inhibitor, guaranteeing the absence of hydrate formation, by turning on the necessary shut-off valves that are installed veins on the inlet pipes of the inhibitor, and the nozzles were used with different capacities or flow characteristics (RF Patent No. 2456500, IPC F17D 1/02, F16L 55/24, application No. 2011125804/06 of 06.24.2011).

A comprehensive automated system for distributing and dosing a hydrate inhibitor is known, comprising an electrically driven pump unit, a pressure header, and inhibitor withdrawal pipes from the collector, the system comprising independent pressure stabilization circuits, one of which is formed by a pressure sensor in the pressure header, the output of which is connected to an automatic controller frequency converter, and the output of the latter is connected to the electric drive of the pumping unit, the second stabilization circuit d detecting unit forms a direct-operated pressure regulator, included in the group of selected devices between the pressure manifold and the actuators (RF patent №2376451, IPC E21B 34/16, Application №2008113485 / 03 dated 07.04.2008).

A known methanol distribution unit, consisting of six nodes of the methanol distribution unit, four of which include six manifolds equipped with valves, the unit is equipped with two control valves, two control valves with actuators, a flowmeter set, the first and second nodes of the methanol distribution unit the free ends of the adapters are connected to the flowmeter set and the flanges of the control valves, the third and fourth nodes of the methanol distribution unit are connected by two free flanges flanges of control valves with actuators, and the other two with flanges of control valves, two fifths of the methanol distribution unit are connected by their flanges to the flanges of control valves with actuators, and the free ends of the pipes are connected to the flowmeter kit, while the free ends of the tees of the first and second unit assemblies methanol distribution is connected to a general methanol piping system and an automatic process control station, and is also equipped with a rack and a rack with a pallet, including vertical supports, horizontal supports, guides, a pallet and a pipe, and the components of the rack are interconnected by welding, while the rack is connected to the rack with the pallet by welding (RF Patent No. 2338237, IPC G05D 7/00, F17D 3/12, application No. 2007124257/06 dated 06/27/2007).

The main disadvantages of these devices are:

- insufficiently high accuracy of dosing of the inhibitor, which leads to its cost overrun and off-design operation of the well;

- the inability to automatically maintain a given flow rate of the inhibitor, regardless of fluctuations in the permissible pressure range in the pipelines;

- the inability to provide a metered supply of a hydrate inhibitor for each channel.

The objective of the invention is to remedy these disadvantages and create a device for supplying an inhibitor, the use of which will provide the ability to control the flow of the inhibitor with a given accuracy in all operating modes.

The solution to this problem is achieved by the fact that the proposed device for supplying an inhibitor to a pipeline of natural gas according to the invention comprises a housing, an inlet and an outlet nozzle for supplying an inhibitor, a filter installed in the line for supplying an inhibitor, preferably after an inlet nozzle, a flowmeter of an inhibitor, a device for controlling the flow of an inhibitor, comprising a housing with inlet and outlet fittings and a working body located inside the housing, and the said device is connected to the flow meter of the inhibitor, while the body of the inhibitor flow control device is made in the form of a plunger pair, the piston of the said pair being made in the form of a cylinder having the possibility of reciprocating motion by an electric drive, while on the outer surface of the specified cylinder there are made radial grooves and at least one longitudinal groove of an alternating a section, preferably triangular, the passage area of which decreases from the peripheral part of the cylinder to its central part, while connecting the cavities of these grooves tsya among themselves.

The device is designed to operate under the control of an automated process control system of an object or local automation systems and provides:

- automatic maintenance of a given flow rate of the inhibitor, regardless of fluctuations in the permissible pressure range in the pipelines;

- dosed supply of a hydrate inhibitor for each channel;

- remote control of the flow rate of the hydrate inhibitor according to the tuning signals from the communication line by the flow rate parameters of the inhibitor;

- alarm about the malfunction of the units that make up the devices.

The invention is illustrated by drawings, where in FIG. 1 shows a schematic diagram of a device, FIG. 2 is a longitudinal section through a regulating valve in the closed position; FIG. 3 - a longitudinal section of the control valve in the open position, in fig. 4 is a general view of the piston (plunger) of the control valve; FIG. 5 is a longitudinal section of a piston (plunger), FIG. 6 is a cross section of a piston (plunger).

The hydrate inhibitor supply device to the natural gas pipeline contains an inlet 1 and an outlet 2 nozzles, a filter 3 installed after the inlet nozzle 1, an inhibitor flowmeter 4 and an inhibitor flow control device 5 with a working member 6. The working member 6 of the inhibitor flow control device 5 is made in the form plunger couples. The piston 7 of said pair is made in the form of a cylinder having the possibility of reciprocating motion. On the outer surface of the piston 7 there are made radial grooves 8 and at least one longitudinal groove 9 of variable cross section, preferably triangular. The passage area of the longitudinal groove 9 decreases from the peripheral part of the piston 7 to its central part. The cavities of these grooves 8 and 9 are interconnected, which allows for a uniform supply of the inhibitor while controlling its flow rate in different modes.

Valves 10 and 11 are used to shut off the automatic inhibitor feed control line. The consumption of the inhibitor can be controlled by the readings of the flow meter 12 displayed on the differential adder of the sensor. In the case of preventive maintenance in the automatic line, it is possible to maintain the flow rate through the bypass line with a manual control valve 13. The bypass line is also designed for commissioning. To exclude the possibility of getting the inhibitor from the system back into the inhibitor supply device, a check valve 14 is used.

The proposed feeder inhibitor operates as follows.

A hydrate inhibitor from a main source of methanol or a pumping unit at a pressure higher than the gas flow pressure is supplied to the device inlet, inlet pipe 1. At the device inlet there is an inhibitor mechanical cleaning filter 3 with a cleaning fineness of at least 40 μm. Next, the input line is divided into two input channels of the inhibitor. Through the valve 10, the inhibitor enters the micrometer 4 and the flow regulator 5 with an electric actuator. By a command formed from the operator’s automated workstation (AWP), the control unit supplies power to the electric motor drive, which changes the flow cross section of the flow regulator 5. If necessary, the flow piston 7 of the working body 6 mixes to the outlet pipe of the flow control 5, the flow cross section the channel of the plunger pair, due to the increase in the bore of the profiled grooves 9, increases, and, accordingly, the consumption of the inhibitor increases. When the flow rate decreases, the piston 7 mixes in the direction opposite to the outlet pipe of the flow regulator body 5, the bore of the plunger pair channel is reduced, and the flow rate is correspondingly reduced.

The fluid flow flowing through the product pipe passes through the micrometer 4. The control system receives from the micro meter 4 data on the missed flow rate of the inhibitor. The controller, comparing the obtained data with the calculated, in case of deviation, corrects the position of the working body 6 of the flow controller 5.

If necessary, with the help of valves 10 and 11 block the automatic line for regulating the supply of inhibitor. In this case, the flow of the inhibitor can be controlled by the readings of the flow meter 12 displayed on the differential adder of the sensor. In the event of a malfunction of the flow regulator 5 or the flow meter 12 in the event of preventive maintenance in the automatic line, it is possible to maintain the flow rate through the bypass line with a manual control valve 13. The bypass line is also intended for commissioning. To exclude the possibility of getting the inhibitor from the system back into the inhibitor supply device, a check valve 14 is used.

The tests of the full-sized hydrate inhibitor conducted by the applicant and the authors confirmed the correctness of the design and technological solutions.

Using the proposed technical solution will allow you to measure and supply a given amount of methanol in real time, to regulate the flow at deviations from the set parameters, as well as to supply methanol to the entry point with different flow rate, because each of the lines is autonomous.

Claims (1)

A device for supplying a hydrate inhibitor to a natural gas pipeline, characterized in that it comprises a housing, an inlet and an outlet nozzle for supplying an inhibitor, a filter installed in the supply line of the inhibitor, preferably after an inlet nozzle, a flowmeter of the inhibitor, a device for controlling the flow of the inhibitor connected to the flowmeter inhibitor and containing a housing with inlet and outlet fittings and a working body located inside the housing, while the working body of the flow control device is inhibited ra is made in the form of a plunger pair with an electric drive, and on the outer surface of the plunger there are radial grooves and at least one longitudinal groove of variable cross section, preferably triangular, the passage area of which decreases from the peripheral part of the plunger to its central part, while the cavities of these grooves are connected between themselves.

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