RU2171776C1 - Reactor of claus process thermal stage - Google Patents

Abstract

FIELD: designs of Claus process thermal reactor stage. SUBSTANCE: reactor consists of cylindrical chamber and tangentially installed burner. The latter presents two concentrical tubes for introduction of acid gas. Said tubes are located in center of burner embrasure in which dissector is additionally installed. Dissector is made in form of cone (semiellipse, hemisphere, etc) to intensify combustion process due to preliminary mixing of air and gas and to ensure uniform flow of combustion products in reaction chamber. EFFECT: considerable increase of hydrogen sulfide conversion degree, efficient mixing of air and gas in burner, reduced oxygen concentration in combustion products leaving reaction space, prolonged service life of catalyst. 5 cl, 1 dwg

Description

 The invention relates to the design of a thermal stage reactor for the Claus process.

 Known is the reactor of the thermal stage of the Klaus process (AS No. 1600074, B 02 J 19/26 "The reactor of the thermal stage of the Klaus process"), comprising a cylindrical body, additional coaxial cylindrical chambers (perpendicular to its axis), burner devices and a boiler -recycler. The intensification of the combustion process is carried out in it due to the interaction of counter rotating flows and the uniform flow of combustion products along the axis of the reactor.

 The disadvantages of this design are the significant metal consumption and complexity of the design, significant energy consumption, flamethrough into the embrasures of the burners and, as a consequence, their destruction.

 Also known is a slit-burner reactor (see Grunwald V. R. "Gas Sulfur Technology". M., Chemistry, 1992, p. 154), which are also called "low-tech" ("Low-tech").

 The disadvantages of thermal reactors with burners of this type include insufficiently effective mixing of air and acid gas at the inlet of the furnace, the absence of an ignition stabilizer, flame penetration into the burner embrasure, destruction of the burner head and fuel gas nozzles.

 The closest in essence to the claimed is the reactor of the thermal stage of the Claus process, described in RU 2145257 C1, 02/10/2000 and consisting of a cylindrical chamber and a tangentially mounted burner.

 The disadvantages of this design are the lack of a device for preliminary mixing of air and acid gas, weak gas recirculation in the reactor volume and uneven flow of combustion products along its axis. This leads to a decrease in the efficiency of the acid gas combustion process, inefficient use of the volume of the reaction space of the reactor, and a low degree of conversion of hydrogen sulfide.

 The aim of the invention is to intensify the combustion process due to preliminary mixing of air and gas, as well as ensuring uniform movement of the combustion products in the reaction chamber.

 Pre-mixing of air and gas is achieved by the fact that in the embrasure of the burner in front of the acid gas supply pipes there is a divider with a base diameter equal to 0.65-0.8 of the diameter of the cylindrical part of the embrasure of the burner. The burner is made in the form of two concentric pipes for the injection of acid gas located in the center of the embrasure of the burner.

 The base of the divider is located in a plane perpendicular to the axis of the burner, and the apex is located in the center of the burner inside the acid gas pipes, which leads to the formation of annular channels between the outer surfaces of the divider, the gas pipe shells and the burner embrasure, the passage areas of which are made in a ratio that ensures isokinetic outflow media from ring channels.

 Ensuring a uniform movement of the combustion products in the reaction chamber is achieved by the fact that the outlet opening of the burner embrasure is made equal to 0.45-0.7 of the diameter of the reaction chamber and is located relative to the axis of the reactor with an eccentricity of 0.05-0.2 of its diameter.

 The drawing shows a General diagram of the reactor.

 The reactor contains a cylindrical reaction chamber 1, a tangentially mounted burner 2 with an annular air chamber 3, blades 4, coaxial pipes 5 and 6 for supplying acid gas, an embrasure of the burner 8, made in the form of a mating cylinder and a truncated cone, a manifold with nozzles 9 for supplying fuel gas and a divider 7, fixed with a vertex inside the acid gas pipes and forming annular channels 10, 11 and 12 between the pipe shells and the cylindrical part of the burner embrasure.

 In this case, the divider can be made in the form of a cone, half-ellipse, hemisphere, disk or a truncated cone.

The reactor operates as follows. Acid gas is supplied to the burner mixing zone through central pipes 5 and 6 and annular channels 10.11 at an angle of 60 - 90 ^° to the axis of the burner, and air through the outer annular chamber 3. Fuel gas enters the reaction chamber through manifold 9. the supply of acid gas in the annular gap 12 between the divider 7 and the embrasure of the burner 8 at an angle to the direction of air flow provides intensive mixing of air and acid gas and stabilizes the combustion process by recirculating the combustion products in a vortex behind the divider, and the diameter A projection equal to 0.65 - 0.8 of the diameter of the embrasure of the burner and ensuring the isokinetic flow of the media in the annular channels exclude the breakthrough of the flame into the embrasure, the destruction of the burner and the collector of fuel gas. A further increase in the ratio of diameters leads to flame separation and unstable operation of the reactor.

 The combustion products through a hole at the outlet of the embrasure of the burner are fed tangentially into the cylindrical reaction chamber.

 Since the outlet opening of the burner embrasure is located eccentrically relative to the axis of the reactor with an eccentricity value of 0.05 - 0.2, and its diameter is 0.45 - 0.70 of the diameter of the reaction chamber, a part of the gas stream is led towards its rotation.

 The supply of a part of the gas flow towards rotation causes a deceleration of gas rotation near the axis of the apparatus, minimization of the tangential velocities in this zone, and alignment of the axial velocity field, i.e. uniform flow of combustion products along the axis of the apparatus in a mode close to the regime of complete displacement. The result is the efficient use of the entire reaction space, which leads to an increase in the degree of conversion of hydrogen sulfide.

 The minimum eccentricity at which a noticeable effect is achieved should be greater than or equal to 0.05, the relative diameter of the burner embrasure is slightly greater than 0.5.

 The presence of a divider allows you to expand the lower limit of the relative diameter of the embrasure to 0.45. When the eccentricity is more than 0.2, the relative diameter of the embrasure is more than 0.7, the rotation of the flow becomes unstable, and the movement of the combustion products is pulsating.

 Comparative tests showed significant advantages of the proposed reactor design over existing with TEKNIR burners. Along with a significant increase in the degree of conversion of hydrogen sulfide (67% instead of 45 - 50%), ensuring efficient mixing of air and acid gas in the burner leads to a decrease in the oxygen concentration in the combustion products leaving the reaction space, which contributes to an increase in the service life of the catalyst.

Claims (5)

 1. The reactor of the thermal stage of the Klaus process, consisting of a cylindrical reaction chamber and a tangentially mounted burner, characterized in that the burner is made in the form of two concentric pipes for the injection of acid gas, located in the center of the embrasure of the burner, and in the embrasure of the burner in front of the acid gas pipes install a divider , the base of which is located in a plane perpendicular to the axis of the burner, and the top is directed inside the gas pipes with the formation between the divider, the cylindrical part of the embrasure g torlets and pipe shells of annular channels, the passage area of which is made in a ratio that provides isokinetic flow of media.  2. The reactor according to claim 1, characterized in that the diameter of the base of the divider is 0.65-0.8 of the diameter of the cylindrical part of the embrasure of the burner.  3. The reactor according to claim 1, characterized in that the outlet hole of the embrasure of the burner is eccentric relative to the axis of the reactor with an eccentricity of 0.05-0.2 times the diameter of the reaction chamber.  4. The reactor under item 1, characterized in that the diameter of the outlet of the embrasure of the burner is 0.45-0.7 diameter of the reaction chamber.  5. The reactor according to claim 1, characterized in that the divider is made in the form of a cone, half-ellipse, hemisphere, disk or a truncated cone.