A method and apparatus for carrying out a reaction between streams of fluids

as) DENMARK

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(12) PUBLICATION NOTICE and 148697 B

DIRECTORATE OF THE PATENT AND TRADE MARKET (21) Patent Application No .: 2922/75 (22) Filing Date: 27 Jun 1975 (41) Aim. available: 29 Dec 1975 (44) Submitted: 02 Sep 1985 (86) International Application No: (30) Priority: 28 Jun 1974 FR 7422620 (51) Intel.⁴: F23D 14/00 (71) Applicant: 'RHONE-POULENC INDUSTRIES; Paris, FR.

(72) Inventor: Francois' Prudhon; FR, Augustin 'Sclcluna; FR.

(74) Prosecutor: Hofman-Bang &amp; Boutard Patent Office (54) Apparatus for conducting a thermal reaction between streams of flowable media

UK 14BO9S D

The invention relates to an apparatus for conducting a thermal reaction between streams of flowable media and of the nature specified in the preamble of claim 1.

From the specification of French Patent No. 2,071,012, such an apparatus is known for combustible combustible waste gases, where the flame can reach all the way to the inner wall of the inner pipe, so that it acts as a heat exchanger between the hot internal combustion gases and those through the annular room supplied waste gases. Thus, the wall of the inner pipe is thermally heavily loaded and heated, so that the heat output provided by the apparatus cannot be quickly adapted to the current requirements.

From the disclosure of U.S. Patent No. 2,564,700, a carbon black furnace is known in which the combustion gases are caused to make a helical movement in the inner tube, from which the axial region of the carbon black is discharged, and whose refractory casing is essentially only heat gases which thermally strongly stress and heat the refractory lining, so that this furnace is also thermally sluggish.

The invention has for its object to provide an apparatus of this kind which is thermally more flexible and thereby enables fine-tuning of the reaction processes by keeping the inner tube wall thermally cold.

This is achieved according to the invention by a construction of the nature specified in the characterizing part of claim 1.

Here, the flow initiated through the annular space penetrates completely in a rotationally symmetrical manner into the interior of the insert, where a helical flow is effected which flows out along the wall of the inner tube. As the pressure ratios are completely rotationally symmetric, at the axis of the inner tube an underpressure region is formed which ensures that the interacting media remain in the inner axial region of the inner tube and does not touch its wall. As this wall is thus neither thermally nor chemically loaded, no special demands are placed on the material, so that, for example, normal steel can be used. The reaction conditions are determined solely by the two streams and not by the actual temperature of the wall of the inner tube, whereby the reaction can be finely and quickly controlled.

The openings in the perforated insert are usually circular and should exhibit at least at the front wall end of the insert a relationship between the hole diameter and wall thickness of more than 5 ·

In the construction of claim 2, the mixing of the two media is promoted and it is prevented that the medium introduced through the inlet pipe does not reach the inner wall of the inner tube.

The tangentially inlet of the annular space is usually disposed near the end of the annular space facing away from the front wall, since this outside of the annular space facilitates the smooth inlet of the helical stream in the openings of the insert.

By placing the inlet pipe further back in the apparatus and distributing the outlet of the gas from the annular space as claimed in claim 3, the flow of cold pipe wall which has already been obtained as a result of the helical flow is promoted.

The ratio between the cross-sectional area of ​​the annular space and the total cross-sectional area of ​​all the openings is preferably between 5 and 15 on a cylindrical casing. The diameter of the inner tube must not be less than 500 mm when a viscous reaction agent is applied in the rectilinear axial flow, for example heavy fuel oil, which is preferably dispersed very finely and homogeneously.

In the construction set forth in claim 4, due to the helical flow, the constricted diameter of the flame burning in the inner tube can be maintained all the way to the pipe end.

Preferably, the helical flow from the annular space passes through the insert apertures at a rate of approx. 15-50 m / s, but also at high starting speeds of the axial current, for example 100150 m / s, the flame is completely enclosed by the helical current. As a result of the suppression prevailing in the central core, hot gas particles are returned to the axis of the core and the flame remains within a cylinder whose radius is approx. 1/3 of the radius of the inner tube when no tuning disc is used. The diameter of the flame is essentially independent of the flow rate of the fuel, but the length of the flame changes as a function of the flow rate.

The invention is further explained below in connection with the drawing, in which:

FIG. 1 is a longitudinal section through a first embodiment of the apparatus according to the invention; FIG. 2 is a section along the line AB in FIG. 1 with access lines projected in the sectional plane, and fig. 3 is a longitudinal section through another embodiment of the apparatus according to the invention.

As shown in FIG. 1, the apparatus according to the invention has a sheath 1 which is closed at one end with a front wall 7 · A cylindrical inner tube 2 is inserted in the sheath 1 so that at the end facing away from the wall 7 a closed annular space 4 is formed. In the direction of the wall, the inner tube 2 is extended with an insert 2 'with openings 3 so that the annular space 4 extends to the front wall 7.

At the end of the annular space 4 facing away from the wall 7, an inlet tube 5 through which gas is introduced tangentially enters into it. Through the wall 7 there is inserted coaxially with the insert 2 'and the inner tube 2, ie. in the axis of the combustion chamber 6 formed by the inner tube 2, an inlet tube 8 which opens into the interior of the insert 2 * and is used for fuel delivery.

On the side 7 of the front wall 7 facing away from the insert 2, there is a cylindrical chamber 10 which is closed by an outer wall 11 extending parallel to the front wall 7 of the apparatus and which is connected to the interior of the insert 2 'through the opening 9 in the front wall 7. In the cylindrical chamber 10, an inlet line 12, which in FIG. 2 is shown tangentially aperture, but which can, however, form any angle with the cylindrical outer surface of the chamber 10.

Through the sheath 1 and the insert 2 there is a spark plug 13 which can be retracted after ignition. In the interior of the combustion chamber 6, at the transition point between the inner tube 2 and the insert 2 *, a tuning disk 15 with a central opening 17 is placed, and at the free end of the inner tube 2 a tuning disk 14 with a central opening 16 is arranged. .

In operation, fuel is introduced through the inlet pipe 8, gas through the inlet pipe 5 and air through the inlet pipe 12. The gas flows through the annular space 4 into a helical stream and enters equally distributed through the openings 3 in the insert 2 'and moves in a helical stream along the outside. of the combustion chamber 6 outwardly. The axial currents which arise in the axial core of the helical current thereby suck in and feed axial currents emerging from the inlet pipe and openings 9. Upon ignition of the spark plug 13, a combustion is initiated, whereby a flame is formed in the interior of the helical stream, the diameter of which is determined essentially by the diameter of the central openings 17 and 16. The parts of the flame which seek to move outwardly towards the inner tube 2 are brought back by the negative pressure prevailing in the axial core towards the axis as shown by the dashed arrows.

In the embodiment of FIG. 3, the outer wall 11 is missing and the front wall 7 is formed without the openings 9.

Instead, there is provided a screen 18 which is attached to a rod 19, which in turn is secured to the inlet pipe 8 by means of a traverse or a cross 20. The air is supplied here through a conduit 21. The mixture of air and fuel, which, in an apparatus of this type, must be substantially gaseous, is first deflected by the screen 18 before it enters the combustion chamber 6 and here assumes the rectilinear flow shape in the central core of the helical gas stream.

A burner of the device shown in FIG. 3 may, for example, have the following main dimensions:

Total length of the appliance: 45cm; inner diameter of sheath 1: 55cm, inner diameter of inner tube 2 and insert 2 ': 42.5cm, wall thickness of insert 2': 5mm. The insert 2 * has 75 openings with a diameter of 20 mm, which form a mesh with the mesh width 5x5 near the front wall 7^cmThe inner tube 2 further has at its end facing away from the wall 7 'a apertures 23, spaced along a circumferential line, 8 mm in diameter.

The apparatus is fed with 100 nP / h methane and with 3000 m 2 / h air. The gases emitted from the burner have a temperature of 800 ° C; the temperature of the perforated insert 2 'is 150 ° C and the temperature of the jacket 1 is 60 ° C.