RU1831366C - Gas-liquid separator - Google Patents

Abstract

Usage: for the separation of biphasic media, in particular during gas pipeline transport. SUMMARY OF THE INVENTION: in a gas-liquid separator containing a gas pipeline with a screw rib and a side outlet installed under the flange of the shaped diaphragm located inside the gas pipeline, the screw rib is made with a step t 2tg Rtg the height of the rib is selected from the condition 0.0015 h / R 0.032, rib made with a T-shaped cross section and drainage holes in the lower part of the gas pipeline, while the end turn of the rib is introduced into the mouth of the branch. 2 ill.

Description

With

with

The invention relates to apparatuses for separating two-phase media, in particular to gas-liquid flow separators, and can be used in pipeline gas transportation when the liquid phase forms a film flow.

The purpose of the invention is to increase the separation efficiency relative to the efficiency of one separation stage while reducing hydraulic losses.

Figure 1 - cross section of the gas pipeline with the elements of the separator; figure 2 is a cross section of a helical rib with a drainage hole.

A gas-liquid separator is mounted inside the gas pipeline 1, equipped with a branch 2 for removing the liquid fraction, installed under the flare shaped. a diaphragm 3 directed against the gas flow shown by an arrow. The diaphragm is made with a rounded gas inlet and a pocket on the rear side

flanges to provide the smallest input impedance — to reduce hydraulic losses and to reliably trap fluids. The latter means that the pocket prevents fluid from flowing from the diaphragm wall to its entrance. An annular coil of a helical rib 4 with a T-shaped cross section is tangentially introduced into the outlet 2. The helical rib is directed from the diaphragm in the direction opposite to the direction of gas flow and has a helix pitch less than the product of the circumference of the inner diameter of the gas pipeline 1 by the tangent of the effective critical angle of elevation of the helical rib 4. i.e.: t 2rRtg Ozf (1)

 The height of the screw rib h must satisfy the condition

0.005 h / R 0.032 (2)

The indicated ratios depend on the internal radius of the gas pipeline t. moreover

00

with

with

oh oh

with

the effective critical angle of elevation is determined experimentally or calculated theoretically from the condition that when the liquid film is twisted by a screw rib 4. the liquid particles do not break off under the action of gravity from the ceiling of the gas pipeline, i.e. so that the centrifugal force of rotation is equal to the force of gravity. The indicated equality of forces is determined by the equality of accelerations

(3)

where g is the acceleration of gravity;

w is the angular frequency of rotation of the film;

R.- radius of the gas pipeline. 2 pm

a) -t

where t is the pitch of the helical rib;

V is the circumferential velocity of the liquid film.

The simplest transformations of formulas (3) and (4), taking into account (1), will give the value of the effective critical angle of elevation

tg bf V / / fV

(5)

The radius of the pipes of real gas pipelines ranges from 75 mm to 750 mm. The peripheral velocity of the liquid film varies in a very narrow range of velocity of 0.5-1 m / s in the boundary layer of liquid and gas with an average axial velocity of gas of 5 m / s - 30 m / s, therefore

20 ° "eff 50 °

For a gas pipeline with an internal diameter of 1 m, the effective critical angle is 24 °, then the pitch of the screw rib 4 should be less than 1.4 m. It is practically advisable to choose a step t of 0.4-1.2 m.

Relation (2) ensures the swirling of the liquid film without swirling the gas component of the flow and is found from the condition that the height of the rib is such that rib 4 is immersed in the laminar sublayer of the turbulent gas boundary layer and protrudes above the liquid boundary layer. From here the coefficients 0.032 and 0.0015 are calculated. Numerically for the same diameter (1 m), the height of the rib is selected within the range of 5-15 mm.

In the lower part of the gas pipeline 1, drainage holes 5 are made in the wall of the screw rib 4 (FIG. 2) in case the number of turns of the screw rib 4 is more than one. The drainage holes are intended for the overflow of liquid film when there is an excess of it at the bottom of the gas pipeline. Usually this phenomenon is rare, since the film flow

evenly distributed over the surface of the gas pipeline 1, however, with volley discharges of liquid into the gas pipeline, the drainage holes 5 increase further

separation efficiency, this also provides a smooth tangential fluid injection along the edge 4 in the outlet 2.

In the process, the gas-liquid separator serves the medium in the gas pipeline 1 through

direction of arrow (FIG. 1). The screw rib 4 twists the liquid film washing the walls of the gas pipeline 1. Moreover, due to the fact that the height of the rib is limited by relation (2) and the rib is immersed in

5, the laminar sublayer of the turbulent boundary layer, the rotation of the liquid does not have time to transmit to the gas component. The gas enters without rotation through the shaped diaphragm 3 cleaned of liquid fraction, the twisted film is cut off by this diaphragm and directed along the annular screw of the rib 4 at the mouth of the outlet 2. By means of the outlet 2, the separated liquid leaves the gas pipeline 1. A T-shaped profile of the cross section of the screw rib 4 prevents fluid from flowing over the edge of the rib. The selected step is less than critical by condition (1). ensures liquid adhesion (continuous flow) in the ceiling part of gas pipeline 1, due to the fact that centrifugal acceleration exceeds the acceleration of gravity.

Thus, the choice of geometric relationships, the shape of the screw petipa and its

5 positions relative to the diaphragm and the outlet, provide an increase in the efficiency of separation of the liquid film flow in the gas, due to the twisting of only the liquid phase without gas during continuous flow of liquid along the rib and in the drain. Liquid spatter and secondary entrainment of droplets are also excluded. In this case, a decrease in hydraulic losses takes place, since the gas component does not twist. No additional turbulent losses also occur, since the rib does not protrude beyond the laminar sublayer of the turbulent boundary layer of gas. The hydraulic loss of friction gas is reduced, so

0 as a liquid film is distributed with the help of a helical rib evenly along the inner surface of the gas pipeline and floods all the roughnesses of the gas pipeline wall.

5 The achieved efficiency of liquid film separation is 100%, excluding fluid entrainment in the aerosol and vapor state. These types of entrainment are not intended to be captured by this separator. Hydraulic resistance

compared with the prototype is reduced by 15%.

SUMMARY OF THE INVENTION A gas-liquid separator comprising a gas pipeline with a helical rib and a side bend installed under a flange of a shaped diaphragm located inside the gas pipeline, characterized in that. in order to increase the separation efficiency while reducing hydraulic losses, the screw rib you // ///////////////,

is completed with a step t determined from the condition

t 27rRtgOa0, where R is the internal radius of the gas pipeline;

 Oeff is the effective critical angle of elevation of the screw rib equal to the 20th Oeff 50 °, the height of the rib h is selected from the condition 0.0015 h / R 0.032, the rib is made with a T-shaped cross-section and drainage holes in the lower part of the gas pipeline, this end of the rib is located at the mouth of the branch.