RU2168460C2 - COAXIAL MIXING MEMBER-BURNER, TYPE "GAS-GAS" FOR COMBUSTION CHAMBER OF highly productive SYNTHESIS GAS GENERATORS - Google Patents

Abstract

FIELD: organic synthesis; devices and technology of processing gaseous hydrocarbon raw materials to synthesis gas (пH₂+CO) by method of nonequilibrium partial oxidizing f hydrocarbon gas by oxygen. SUBSTANCE: proposed mixing member has cooled cylindrical housing, two and more coaxial passage for separate introducing of oxidizer and combustible component into reaction zone of combustion chamber in mixture with corrector gases CO₂ and H₂O or without these gases, end cooled bottom, oxidizer and combustible component delivery units, cooling component delivery and discharge units. Coaxial passages whose flow areas are equal to 0.02-0.1 of free area of end bottom are made for tangential twisting of combustion component and oxidizer; to this end, inlet of each coaxial passage is provided with tangential bypass holes and screw feeders are mounted at outlet of each coaxial passage. EFFECT: enhanced efficiency of mixing and high completeness of combustion. 4 dwg

Description

The invention relates to the field of organic synthesis, namely to devices and technology for processing gas hydrocarbon feedstocks into synthesis gas (nH ₂ + CO) by the method of non-equilibrium, partial oxidation of hydrocarbon gas by oxygen. This invention can be used to create synthesis gas generators with high volumetric productivity and high, not less than 0.9, the conversion rate of the source gas into synthesis gas (carbon).

Gas-to-gas coaxial burners are known and widely used in various heat engineering devices, including high-temperature hydrocarbon-gas reactors. Known burner, made in the form of a rod with a water-cooled casing, in the upper part of which are placed the supply of oxidizing agent, natural gas, gas-corrector composition of the synthesis gas (H ₂ O, CO ₂ ), and in the lower part is a device for introducing components into the reaction zone in the form of two coaxial channels located on the periphery of the end of the bottom cooled by water. Convertible gases are introduced into the reaction zone of a large volume reactor with lined walls or by axial flow along different axes at different speeds, or one of the flows has a tangential twist. The burner forms a macro-vortex, circulation flow of combustion products in the reaction volume (the reactor, together with the burner, essentially forms an ideal mixing apparatus).

 Known coaxial burners mounted in synthesis gas generators (see US patents 2582938, NKI 48-196, 01/15/52; U.S. 3945942, NKI 252-373, MKI C 01 B 1/16, 03/23/77, U.S. 4582630, NKI 252-373, MKI C 01 B 3/36, 04/15/86; USA 5087270, NCI 48-127.9, MKI B 01 J 7/00, 02/11/92; USA 5358696, NCI 423-610, MKI C 01 B 3 / 24, 10/25/94). In these patents, not only the burners themselves are described, but also the organization of circulating flows in an ideal mixing apparatus.

Known multifunctional coaxial burner for synthesis gas reactors, which is presented in UK patent 2219003, NKI C5E, MKI C 01 B 3/36, 11/29/89 (Shell company applicant), adopted as a prototype. It contains five concentric channels for the axial inlet of convertible gases, liquid-phase hydrocarbons and solid pulverulent fuel (coal), but the last two components may be absent. In the absence of the spirit of the latter components, the burner is a gas-gas coaxial burner having five zones for introducing convertible gases. The intensification of mixing of convertible components was achieved by setting substantially different axial velocities for each of the five zones. In this case, the oxidizing agent is supplied, for example, through the first and third zones at a speed of 50 - 150 m / s, natural gas is supplied through the central and fourth peripheral zones at a speed of 5 - 84 m / s, and through the second peripheral zone at a speed of 0 - 15 m / s a mixture of gases with a low hydrocarbon content (for example, a mixture of natural gas and CO ₂ ) is supplied. The multifunctional coaxial burner according to this patent is intended for use in synthesis gas generators with a ratio of H ₂ / CO = 1 - 1.6, operating at a pressure of up to 12 MPa (mainly at 4 MPa) and at an average temperature of 1400 ^o C, forming an ideal apparatus blending.

 The fundamental difference that defines the purpose of the present invention, the proposed coaxial mixing element - burner from the prototype is to ensure effective mixing and high combustion only near the end of the burner bottom (from the combustion chamber of the generator) by creating a structured vortex zone when using the burner in the direct-flow synthesis generators gas, in which the schemes of ideal mixing and ideal displacement are combined.

 This goal is achieved by ensuring high-speed regimes of the outflow of coaxial jets, namely, by intensive and mutually opposite tangential twist of each of the coaxial flows, while maintaining approximately equal modulo moments of the momentum of the flows and observing a certain ratio of the areas of the passage section of the coaxial channels in which swirling flows move to the free end face area burner bottoms.

 To achieve this goal in a coaxial mixing element-burner, containing coaxial channels for separately entering into the reaction zone of the combustion chamber of the synthesis gas generator of a gaseous oxidizer and a combustible component, an end cooled bottom, nodes for supplying an oxidizer and a combustible component, nodes for supplying and discharging a cooling component, tangential bypass holes are made at the input of each coaxial channel, screws (swirlers) are installed at the output of each of them, and the cross-sectional area of the coax cial channels is 0.02 ... 0.1 the mechanical burner bottom free area.

 In FIG. Figure 1 shows a general view of a coaxial mixing element - a burner with two coaxial channels (one belt) for introducing components, which is the main modification.

 In FIG. 2 is an end view of the coaxial mixing element — the burner shown in FIG. 1.

 In FIG. 3 and 4 show options for the main modification.

 The proposed coaxial mixing element - the burner contains a cooled cylindrical body 1, a cooled end bottom 2, a peripheral path for supplying one of the main components, for example a combustible component 3, a central path for supplying a second main component (for example, an oxidizing agent) 4, made in the form of coaxial cylinders, nodes the supply of the main components 5 and 6, the supply and outlet of the cooler 7, the mounting device with adjacent assemblies 8. On the paths of the supply of oxidizing and combustible components containing additives g Adjustment nozzles 9 and 10 are installed at the inlet to the mixing element or without them, and tangential bypass holes 11 and 12 are made at the entrance to the component input channels into the reaction zone, which ensure the flow twist required by the magnitude and direction, reinforced by screws - multi-screw helical fins 13 and 14 installed at the outlet of each coaxial channel, near the cut-off of the flows entering the reaction zone of the combustion chamber of the synthesis gas generator.

 The proposed coaxial mixing element - burner operates as follows. The combustible component and the oxidizing agent are separately fed through the adjusting jets 9 and 10 to the supply nodes of components 5 and 6, and from there to the coaxial channels, at the entrance to which tangential bypass openings 11,12 are made. Passing through the indicated bypass holes, the threads swirl in exactly opposite directions. The thread twist is enhanced by 13.14 screws. Each of the swirling flows flows in the form of circular jets outward (into the combustion chamber of the synthesis gas generator), forming a structured vortex zone near the end face.

The tangential twist of both flows is such that the moduli of the angular momentum of the flows are approximately equal. The moment of momentum of the flow is rm V _τ, where r is the effective radius, m is the mass flow rate, V _τ is the tangential component of the velocity at the channel section (see Fig. 2, view A). The tangential flow velocity lies in the range of 50 ... 150 m / s, the axial flow velocity, determined by the passage sections of the channel, is 10 ... 30% of the tangential velocity. The characteristic size for the coaxial mixing element - the burner - is the outer diameter of the end face D (see Fig. 1), lying in the range of 70 ... 180 mm.

 The formed developed vortex zone near the end bottom of the coaxial mixing element - the burner depends, as the calculations show, not only on the flow velocity parameters, but also on the end bottom geometry: on the ratio of the total output flow area (the area of the passage sections of the coaxial channels) to the free area of the end bottom. The optimal ratio of the areas is 0.02 ... 0.1.

In FIG. 3 shows a modification of a coaxial mixing element with a free portion of a cooled end face in the center. The ratio of the diameter D _{1 of} this section to the outer diameter of the end of the bottom D lies in the range 0.2 - 0.5, while the ratio of the total passage area of the coaxial channels to the free area of the end of the bottom is 0.02 - 0.1.

 In FIG. 4 shows a modification of the mixing element with the number of component entry belts more than one, the ratio of the total input area of the components to the free bottom area is 0.02 - 0.1. In each of the additional coaxial channels, tangential bypass holes are made at the inlet, and screws are installed at the outlet. The proposed coaxial mixing element - a burner as a single gas-gas mixing element can be used for combustion chambers of synthesis gas generators with a flow rate of a combustible component (hydrocarbon gas) of 0.375 - 3.75 t / h and a pressure in the reaction zone of the combustion chamber 2 - 15 MPa

Claims (1)

Gas-gas coaxial mixing element-burner for combustion chambers of high-performance nH ₂ + CO synthesis gas generators, containing a cooled cylindrical body, two or more coaxial channels for separately introducing an oxidizer and a combustible component in the gas mixture into the reaction zone -korrektorami composition of CO _2, H ₂ O or without mechanical cooled bottom, the oxidant supply units and fuel component feeding units and discharging cooling component on the opposite side, characterized in that the coaxial s channels, whose opening area is equal to 0.02. .. 0.1 of the free area of the end bottom, made with the possibility of tangential swirling in opposite directions of the jets of the combustible component and the oxidizing agent, for which tangential bypass holes are made at the input of each coaxial channel, and screws are installed at the output of each of the coaxial channels.

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