SU498024A1 - Mixer - Google Patents

Description

(54) MIXER

one

The invention relates to equipment for mixing gas components, it can be used in the petrochemical and chemical industries.

A tubular type mixer is known for the preparation of mixtures, comprising a housing, inlet and outlet fittings, distribution grids in which tubes of porous material are installed.

In a known mixer, it is possible to prepare hydrocarbon-oxygen mixtures at temperatures up to 300 ° C. At temperatures above 300 ° C, the mixture self-ignites in the mixer.

Self-ignition of the mixture in the mixer due to the lack of homogeneity of hydrocarbon-oxygen mixtures. In addition, in a known mixer, the speed of the mixture along the length of the tubes in which the mixing takes place is uneven. The pore size is different, and therefore through them comes a different amount of oxygen. This leads to the fact that zones rich in oxygen appear in the mixing chamber, causing the mixture to ignite at temperatures above 300 ° C.

The purpose of the invention is to eliminate these drawbacks and to obtain homogeneous hydrocarbon-oxygen mixtures heated to a high temperature, as well as to maintain a uniform mixture rate throughout the length of the tubes and to eliminate stagnant zones. The goal is achieved by the fact that the ratio of the average cross-sectional area of the tubes to the cross-sectional area of the holes in them is 3.6-5.0, and the ratio of the pitch of the holes to their diameter is 10-20, the ratio of the cross-sectional area of the tubes at the mixture inlet to the area the output section of the tubes is 0.7-0.8. In addition, an additional grid is installed in the housing, the cross-sectional area of the openings of which is 2-3% of the average cross-sectional area of the tubes.

FIG. 1 shows the proposed mixer, a longitudinal section; in fig. 2 is a section along LL in FIG. 1; FIG. 3-section on BB

g g 1 1 tp1

hd fn1 i.

in the cylindrical housing 1 of the mixer there are upper 2 and lower 3 grids in which tubes 4 with openings 5 are mounted. To dampen the velocity pressure of the oxidizer and distribute it through the tubes, there is a scroll 6. At the bottom of chamber C}, esh1; ; There is a grill 7 with openings 8: i fitting 9 for supplying inert gas. To quench the velocity head of hydrocarbons, nocTynaionj; iix for mixing, and to evenly distribute them, a grate 10 is installed in the tubes.

The described mixer works as follows.

Hydrocarbons through the fitting 11 and the distribution grid 10 are fed to the mixture in the tube 4. Oxygen through the fitting 12, mine scissors 6, the slits 14 in the reactor vessel and the holes 5 in the tubes 4 is fed to the mixture with hydrocarbons. At the outlet of the tubes 4, an inert gas is supplied through the fitting 9 and the openings 8 in the grid 7 to the hydrocarbon-oxygen mixture, thus eliminating the formation of stagnant zones and ignition of the mixture.

Example. On the experimental model of the mixer, methane-oxygen mixtures are prepared at a temperature of 750 ° C. Methane consumption 200, oxygen consumption 105. The mixer consists of 4 tubes with a total cross-sectional area at the inlet of 10 meters and at the outlet of the mixture 5-10 m. The cross-sectional area of the holes with a diameter of 2 mm in the tubes is 1.1-10 m, the distance between the holes is 15 diameters ( 30 mm). At the outlet of the mixture from the tubes, nitrogen is fed in an amount of 3 vol. % of methane.

The mixing device operated for 100 hours; no self-ignition of the mixture was observed.

When the ratio of the cross-sectional area of the tubes to the cross-sectional area of the holes in them, through which the oxidant is 3.6-5.0, uniform penetration of oxygen jets into a stream of hydrocarbons and high-quality mixing of components during a time shorter than the period of self-ignition is ensured mixes.

With a hole pitch equal to 10–20 diameters, a stream of oxygen 2-3 mm in diameter manages to move, thereby eliminating the formation of areas rich in oxygen, and at a step less than 10 diameters of the holes, there is no quality mixing and the mixture at 600 ° C ignites. A step of more than 20 diameters leads to an elongation of the apparatus and, thus, an increase in the mixing time.

In the mixing device, there should be no stagnant zones that can ignite the hydrocarbon-oxygen mixture.

To eliminate stagnant zones that

occur at the outlet of the mixture from the tubes; an additional grid is installed, through which inert gas is supplied. The cross-sectional area of the holes in the grid is 2-3% of the average cross-sectional area of the tubes,

which feeds the mixture. When the cross-sectional area of the holes in the grille is below 2% of the total cross-sectional area of the tubes, the completely stagnant zones are not eliminated and the mixture self-ignites in the mixer. An increase in the opening cross-section of more than 3% leads to an increased consumption of inert gas and dilution of the mixture with inert gas.

Claims (3)

1. A tubular type mixer for preparing gas mixtures, comprising a housing, inlet and outlet fittings, distribution grids in which tubes with holes for blending are installed in parallel, characterized in that in order to obtain homogeneous hydrocarbon-oxygen mixtures heated to a high temperature, the ratio of the average cross-sectional area of the tubes to the cross-sectional area of the holes they are 3.6–5.0, and the ratio of the pitch of the holes to their diameter is 10–20. 2. A mixer according to claim 1, characterized in that, in order to maintain a uniform mixture velocity throughout the length of the tubes, the ratio of the cross-sectional area of the tubes at the inlet of the mixture to the cross-sectional area of the tubes at the outlet is 0.7-0.8. 3.Mixer according to paragraphs. 1 and 2, characterized in that, in order to eliminate stagnant zones, a lattice is additionally installed in the housing, the cross-sectional area of the openings of which is 2-3% of the average cross-sectional area of the tubes. / J / J.