RU2464484C1 - Plant for investigation of outflow of liquefied hydrocarbon gases - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: plant is designed for investigation of outflow and determination of liquid flow rate coefficient at emergency break of wall of pipeline transporting liquefied hydrocarbon gases. Pressure measuring instrument for saturated vapours in cavitation zone of pumped liquid is introduced to the plant scheme, and the scheme itself is tight during operation and excludes the escape of liquefied hydrocarbon gases to atmosphere. As pressure measuring instrument for saturated vapours there used is Venturi pipe or conical convergent-divergent head piece with intermediate cylindrical part, which allows simulating the cavitation zone in model hole or in head piece, measuring medium pressure (for example at outflow of the liquid from the hole in "thick" wall of pipeline or long head pieces at available flow separation, which is determined with cavitation).

EFFECT: higher measurement accuracy of flow rate coefficient; providing the flexibility of its value for various component composition of liquefied hydrocarbon gases, as well as providing environmental and fire safety.

2 cl, 1 dwg

Description

The invention relates to pipeline hydraulics and can be mainly used to determine the coefficient of fluid flow during emergency rupture of the wall of the pipeline transporting liquefied hydrocarbon gases.

In the event of an emergency rupture of the pipe wall, the question arises of the amount of fluid flow from the gap formed at the place of pipe rupture. A reliable determination of the flow rate primarily depends on how correctly determined the flow coefficients, the living area of the slit, having a complex configuration. The task is further complicated by the fact that direct measurements of the area and assessment of the configuration of the gap during an accident are practically impossible.

A technical solution is known (see D.S. Wilker "Laboratory Workshop on Hydraulics" - Fizmatgiz. - 1959. - P.150-153), which includes a vertical cylindrical vessel, a drain, a piezometer, a metal ruler with millimeter divisions and a slider moving on it.

The disadvantage is that this installation is applicable for small heads, in addition, in the absence of liquid in the vessel, a round hole is installed, the diameter of which is previously measured, and the inability to use for the investigation of fluids with high vapor pressure P _p ≈ (2 ÷ 20) · 10 ⁵ Pa.

A technical solution is known (see. Laboratory course of hydraulics, pumps and hydraulic gears. Edited by S. S. Rudnev and L. G. Podvidza. Ed. 2nd, revised and enlarged M .: Mashinostroenie, 1974. - P.177 -179), which includes a supply pipe with a gate valve, a bell with a manometer and a needle throttle, a stilling tank with a honeycomb jet straightener, a thermometer, a piezometer and a crane, as well as a transfer device, a measuring tank, a three-way valve and a mercury cup manometer.

The disadvantage is that due to leaks in the hydraulic system, the installation cannot be used for liquefied petroleum gases.

The closest technical solution is (see Topical issues of oil pipeline transportation. VNIISPTneft. - Ufa. - 1986. - p. 74), which includes pressure and acceptance tanks connected to the pump unit, an overpass serving as an observation point during removal indications of the process of fluid flow through the diamond-shaped slots from the pressure vessel to the receiving. In addition, the pressure vessel is equipped with a piezometer and a flange, on the surface of which specially made metal plates are mounted - washers with slots of various sizes.

The disadvantage is that due to the limited pressure, the phenomenon of cavitation and flow stall in the outflow channel of the tested model are not taken into account. In addition, the working fluid is in contact with the atmosphere, i.e. tightness is not ensured and, therefore, unsuitable for working with an unstable liquid - LPG.

The objective of the invention is to improve the accuracy of measuring the flow coefficient, ensuring the universality of its value for LPG of various component composition, as well as ensuring environmental and fire safety.

The problem is solved and the technical result is achieved by the fact that the installation for studying the outflow of liquefied petroleum gases (LPG) from model holes or nozzles simulating the outflow through emergency slots of pipelines consists of an injection unit for LPG, a test container with an outlet unit, while the new one is the fact that a device for measuring the pressure of saturated vapors in the cavitation zone of the pumped liquid is introduced into the installation circuit, and the circuit itself is leakproof during operation, eliminating the emission of LPG into the atmosphere.

In this case, the best technical result is achieved if a Venturi tube or a conical converging-diverging with an intermediate cylindrical part of the nozzles is used as a device for measuring the pressure of saturated vapors, which allows simulating the cavitation zone in a model hole or nozzle, and measuring the pressure of the medium into which the outflow takes place ( for example, when liquid flows out of an opening in a “thick” wall of a pipeline or long nozzles in the presence of a flow stall due to cavitation).

The figure shows the technological scheme of the installation.

The installation includes a nozzle for receiving liquefied gas 1, a supply tank 2, a pump 3, a bypass line 4, a relief valve 5, a cavitation tube 6, a battery of flowmeters 7, pressure gauges 8, a test tank 9, safety valves 10, a gas discharge line 11, a collecting tank 12 , inert gas cylinder 13, pressure regulator 14, shutoff valve 15, flame arrester 16, diffusion candle 17 and expiration unit 18.

The method is as follows.

Before receiving the liquefied gas, the testing apparatus 9 and the piping system are purged with nitrogen from a cylinder 13 provided with a pressure regulator 14, and the consumable capacity-testing apparatus is gradually gaining pressure in the piping system. In the apparatus for testing pressure is visually controlled by a manometer 8.

Between the test tank 9 and the collection tank 12 there is a test assembly 18 in which replaceable models of the emergency gap are located - test objects.

Liquefied gas through the inlet pipe 1 enters the flow tank 2, from where it is pumped to the bypass line 4, the discharge valve 5, the LPG bypass line and then to the flowmeter battery 7 and the cavitation tube 6 of the Venturi type, then into the test tank 9 with the installed manometers 8 at its inlet and outlet and safety valves 10 at the outlet of containers 2 and 9, the discharged gas from which, as well as gas from the discharge line 11 from the discharge tank 12, enters the dispersion candle 17 with a flame arrester 16.

Using the invention, it will be possible with high accuracy and reliability to determine the flow rate of unstable (LPG, unstable condensate) fluid through model openings and, with a known pressure drop, to determine the desired value — flow coefficient.

Claims (2)

1. Installation for studying the outflow of hydrocarbon gases (LHG) from model holes or nozzles simulating the outflow through emergency slots of pipelines, consisting of an LHG injection unit, a test container with an expiration unit, characterized in that a device for measuring saturated pressure is introduced into the installation diagram vapor in the cavitation zone of the pumped liquid, and the circuit itself during operation is tight, eliminating the emission of LPG into the atmosphere. 2. Installation according to claim 1, characterized in that as a device for measuring the pressure of saturated vapors use a venturi or conical converging - diverging from the intermediate cylindrical part of the nozzles, allowing to simulate the cavitation zone in a model hole or nozzle, to measure the pressure of the medium into which an outflow occurs (for example, when a fluid flows out of an opening in a “thick” wall of a pipeline or long nozzles in the presence of a flow stall due to cavitation).