DD210733A1 - CARBON BURNERS AND METHOD FOR ITS OPERATION - Google Patents

Abstract

The invention relates to a pulverized coal burner and a method for its operation, wherein the coal dust is supplied in a concentrated stream. The goal is to increase the operational reliability of the burner and to improve the quality of the gasification gas produced from the pressure gasification of dust-containing carbonaceous materials. The object is in the structural design of the pulverized coal burner, which corresponds to the operating conditions in the pressure gasification of coal dust, works reliably and is technologically easy to create. According to the invention, the pulverized coal burner consists of a housing, a built-in channel in its central axis for the supply of coal dust, arranged at the periphery of the channel channels for the supply of the oxidant, which are provided with outlet openings, and with a nozzle for the Wassereinampfeinfuehrung and a Duese is provided for the exit of the same.

Description

Title of the invention

Pulverized coal burner and method for its operation

Field of application of the invention

The invention relates to a pulverized coal burner and a method for its operation, wherein the coal dust is supplied in a concentrated stream. The field of application is primarily in the chemical industry in the gasification of coal.

Characteristic of the known technical solutions

There is known a pulverized coal burner having a housing, a channel arranged along the central axis for the supply of pulverized coal and arranged along the periphery and directed at an angle to the burner axis channels for the Säuerstoffzuführung. It should be considered that the exit ends of these channels are fixed to the channel for the supply of coal dust (Patent Prankreichs No. 23 65 628, Class C 10 J 3/46, 1976).

The burner works in the following way: "the central channel is used to feed the concentrated pulverized coal stream (with carrier gas), through which the oxidizing agent feeds the oxygen that flows directly into the coal dust stream from the burner to the reactor supplying a mixture of coal dust and oxygen.

Such a burner has significant disadvantages:

1. In the burner, internal flame propagation is possible when the regime is changed, and particularly when the load is depressed, because the exit ends of the oxidant supply channels are attached to the coal dust feed channel and the mixing process of oxygen and pulverized coal within the burner takes place , This reduces its operational reliability,

2 "Delaying the pulverized coal gasification process by passing the pulverized coal feed from the burner into the reactor together with the oxygen in a compact, straight (untwisted) jet.

3 'difficulties in the delivery and mixing of the water vapor with the pulverized coals in that the coal dust is zugefühit at temperatures below 50 to 60 ⁰ C and is the required amount of steam in the range of 0.1 to 0.3 kg / kg and at the feed the vapor into the Kohlenstaubstram together with the oxygen the condensation of the steam will take place, which leads to a clogging of the coal dust channel,

4. Uneconomic consumption of oxygen and the possibility of burning the burner mouth in that the concentration of oxygen in the exiting mixture jet-very high and therefore when mixing the effluent stream with the hot gases from the gasification, the combustion of the latter to the occurrence of very high temperatures in near the burner.

The burner closest to the invented burner in terms of technical character and effect achieved is a pulverized coal burner comprising a housing, a duct for supplying the pulverized coal along the central axis of the burner and channels for the supply of oxygen with discharge nozzles along the periphery which are mutually exclusive

arranged overhead and directed at an angle to the burner axis (copyright USSR Ur. 787786, class G 23 D, 1/06, 1979).

The well-known burner operates in the following manner: About the central channel, the supply of coal dust (with carrier gas) takes place directly into the reaction space, Through the channels for the supply of the oxidizing agent, the supply of oxygen, which also flows into the reaction space. The fact that the exit of the channels are directed at an angle to the axis of the burner, the oxygen jets enter the coal dust stream and mix with him. Thereafter, the combustion and gasification process,

However, this burner has the following disadvantages:

1. The low-intensity process of mixing pulverized coal with the oxidant when the straight beams meet due to the arrangement of the exit ends of the channels of the oxidant, which delays the mixing process and hence the gasification process, which in turn leads to a Deterioration of the quality of the gasification gas produced (its composition and calorific value),

2. Uneconomic Säuerstoffverbrauch and risk of combustion of the burner mouth in that the escaping oxygen burns in the immediate vicinity of the exit point before hitting the coal dust in the recirculation flow of the gasification gas. This leads to a reduction in the quality of the gas produced and to a deterioration of the operational reliability of the burner,

3. Possibility of slagging the burner mouth at the exit point of the coal dust stream characterized in that the gasification gases contained slag particles in the molten state, the coal dust stream a

has very low temperature and at the exit cross section of the coal dust channel cooling the Schlakke and her Pestkleben the burner is possible. This phenomenon reduces the operational reliability of the burner,

Object of the invention

The aim of the present invention is to increase the operational reliability of the burner and to improve the quality of the gasification gas produced from the pressure gasification of dusty carbonaceous materials.

Explanation of the essence of the invention

The object of the invention is the structural design of a pulverized coal burner, which corresponds to the operating conditions in the pressure gasification of coal dust, works reliably and is technologically easy to create.

According to the invention, the pulverized coal burner consists of a housing, a built in its central axis channel for the supply of coal dust, arranged at the periphery of the channel channels for the supply of the oxidant, which are provided with outlet nozzles, which are directed at an angle to the burner axis, and which is provided with a nozzle for the supply of water vapor and a nozzle for the outlet thereof, wherein the outlet nozzles of the channels for the supply of the oxidizing agent in the direction of the tangent of the base circle with the radius r show:

0.5 .R ^ r - 0.8. R

R - radius of the outlet opening of the channel for the supply of coal dust, wherein the distance $ between the centers of the outlet openings of the channels for-,

the supply of the oxidizing agent and the pulverized coal is in the following range:

R f I <r:? - R f 5. d

d - diameter of the outlet openings of the channels for the supply of the oxidizing agent is *

According to the invention, the pulverized coal is mixed with the oxidizing agent in a steam stream which contains 6.5 to 9.5 percent by volume of oxygen.

Figure 1 shows the change in the relative momentum of the coal dust flow as a function of the radius of the base circle (r / R),

M - moment of movement of the oxidant flow

at maximum radius r = R. The "dotted line corresponds to the moment of movement of the oxidant flow at variable radius r. At a value r < 0.5 * R, a sudden decrease in the total moment of movement of the pulverized coal flow is determined by the oxidant flow penetrating deeply into the coal dust stream, forcing the inner layers to rotate, the outer layers being thrown away from the total flow and receiving no rotational movement. At r> 0.8 R, a tearing of the outer layers of the pulverized coal stream and even a and passing a portion of the oxidant stream. The inner layers receive no torque.

Figure 2 shows the dependence of the relative mo-

^ mm R

If this is the movement of the parameter - ~ jr- ( since R and d are constants, this dependence on S ) is shown.

 «« M isfc the moment of movement of coal dust moment

with minimum possible distance between the

Centers of exit soff riungen for the oxidant stream and the coal dust stream:

In a reduction of the distance £ below this limit, the nozzle for the oxidant generally meets the coal dust flow, It is an early ignition of the pulverized coal with decommissioning of the pulverized coal burner and destruction of the pulverized coal flow possible. At a value of £> R f 5. d, a sudden reduction in the momentum of the movement of the coal dust stream is noted, which is related to the fact that at a distance from the nozzle edge for the oxidant to the point of encounter with the coal dust stream $ - R> 5, d the core of the Oxidant jet disappears at maximum speed and the mean velocity of the outgoing stream begins to drop sharply.

The calculation of the acid content in water vapor is based on the following empirical formula, which was established on the basis of an analysis of test results for gasification and combustion-solid fuels:

t - required temperature at the point of coincidence of the steam flow with the gasification gases at the burner mouth, which guarantees that no slagging occurs. It is determined to be t = t / 200,

ils

wherein tv temperature of the normal HLüssigschlackenabnz

management of the coal in question;

t, - average temperature of the incoming media streams (water vapor, oxidizing agent, coal dust).

Since virtually all coal t • is in the range of 1100 to 1500 ⁰ C and the average temperature of the incoming media streams in the range of 100 to 200 ⁰ C are, the range of change of oxygen concentration in the range of 6.5 to 9.5 vol. -%. At an oxygen concentration below the lower limit, a slagging of the burner mouth will occur for all types of coal. At oxygen concentration above the upper limit, overheating of the burner mouth will occur with a shortening of the operating time or an immediate forced shutdown of the burner.

Figure 3 shows the proposed burner in longitudinal section.

Figure 4 shows the cross-section of the burner.

The proposed burner consists of a cylindrical housing 1, which is arranged with a nozzle 2 for the supply of water vapor and a nozzle 3 for its exit, a built-in in the central axis of the burner round duct 4 for the supply of pulverized coal, on the periphery ( also round) channels 5 for the supply of the oxidizing agent is provided with outlet nozzles 6, which are installed at an angle to the axis of the burner, wherein the axis of the outlet nozzles in the direction of the tangent of the base circle with the radius r, wherein

0.5 £ _r 6 o, 8 .R

and the distance S between the centers of the outlet openings of the oxidizing agent and the pulverized coal is in the range:

The channels 5 for the supply of the oxidant

are attached to a pipe guide 7, which is located between the housing 1 and the chamber 8 for the distribution of the oxidizing agent, which is provided with an inlet connection 9.

The proposed burner operates as follows: After the Gaspilot burner ignited in the reactor and the operating pressure (30 atm) was adjusted via channel 4, the supply of concentrated coal dust stream with carrier gas (nitrogen), per 400 kg lignite dust are fed per one operating cubic meter of nitrogen , About the nozzle 2, the supply of water vapor, which flows out of the nozzle 3. About the nozzle 9, the supply of oxygen, which enters the chamber 8 and is distributed over the channels 5. The oxygen enters the water vapor from the outlet nozzles »

embodiments

Pure gasification is used for lignite with an increased content of iron oxide. In this case, the temperature for the normal Flüssigsefrlackeabführung t ν 1100 ⁰ G, On a kilogram of coal dust with a temperature of 50 ⁰ C leads to 0.3 Nirr water vapor having a temperature of 600 ⁰ G and 0.5 Mm oxygen at a temperature of 200 C too. The average temperature of the media streams 200 ⁰ G, the water vapor is added to the oxygen so that its concentration in the mixture is 6.5 % . The outlet nozzles 6 are arranged so that the distance between the centers of the outlet openings of the pulverized coal and the oxidizing agent is ε = R fw and the axis of the nozzles 6 for the oxidizing agent in the direction of the tangent of the base circle with the radius r = 0.5. R show.

The oxygen exiting the nozzles 6 arranged in the aforesaid manner causes a rotation

Movement dec coal dust out. The concentrated stream is dissolved and mixed vigorously with the oxygen and water vapor. Then begins the intensive combustion and the subsequent gasification of the coal dust.

Characterized in that in the water vapor 6, -5 % oxygen are contained, a temperature of 1300 ⁰ C is maintained at the burner mouth and a slagging of the burner mouth does not take place.

Example 2

For the gasification a coal with a temperature ti '= 1500 ⁰ C is used. The media streams are maintained in terms of throughput as in Example 1. But the temperature of the water vapor is 230 ⁰ C and the Säuerstofftemperatur 120 ⁰ C. The average temperature of the media streams is 100 ⁰ C. The water vapor is led to oxygen to a concentration of 9.5%. The outlet nozzle 6 is in the direction of the tangent of the base circle with the radius r = 0.8. R and at a distance S = R + - 5. d arranged between the centers of the outlet openings of the oxygen and the pulverized coal. A slagging of the burner mouth does not take place in this way and the process of combustion and gasification proceeds intensively.

The proposed pulverized coal burner has the following advantages:

1. The fact that the channels for the supply of coal dust and the oxidizing agent are made round and show the axes of the outlet nozzles of the channels for the supply of the oxidant in the direction of the tangent of the base circle with the radius r:

0,5. R - r - 0.8. R in which: R - radius of the outlet opening of the channel for the feeding of the pulverized coal,

and jde ^. ^ stif ^ d., J ,. between the centers of the outlet openings _; for d, feed, oxidizer and coal dust . in the, ^ range is:,. ' _r ~

& $ - ί> ψ \ d / ³ '*' ^u * "In what: - ¹ - ^; -

d - d _; eryPurphmesser. 4.er .4ustrittsöffnung fiär the supply of the oxidizing agent is,] '' to reach an intense mixing of Kohlenstäubströmes with ^one of the 'E ^ dätioÄsriiittei'unter'Bildung^'; s a red he ι end en ¹ Ot ro nies'' Öabei 'is performed "" a tack ^strength: combustion' RHIT and gasification äes ^{köhlenstäubes';} Brzeu- supply ^r ', a high cooking Customize' gas (in terms of composition and iäes' liei ^ viärtöB). ^{1 : ;} Characterized in that 'Breriheirgehäüse'^;mii; 6ihem \ ^y stud ^; ! ^zen: for the ^l ^ ^supply: - 'v © n • LASB-erdampf - and ieiner _{AustrittsdU-;} , se fi3r * vd £ ese1n ^; Jverseli ^ ni i s _"t;?, And" the fact that the Ver-- _i;. Irait Kohlenstaub'es;; mischuiSg of Vd em / oxidation Smitt el ^ri in Wasserdämpf done strdm; ^ cliegt Seini uneconomic fields ^ _·?; · ,. Ii rather -ver ^ not Oudh avoii oxygen _x; ^ before it -and:; '. · ¹ danger einesr ^ Wegbiteniiensι of, burner mouth This leads zuoeiner ^ Verbesserungvder'Gasqualität _and;; to'entfallt-'the"öirier Increaseoroperational reliability of;;: _; :.

3. By that, 'that the; Wasserdampfa6, -5 /; contains up to 9.5 vol .-% oxygen, the temperature of the flow is maintained in the immediate vicinity of the burner mouth above the temperature of the normal liquid slag removal and a slagging of the burner does not take place. This increases the operational reliability of the burner.

Since there are no burners in the USSR operating in gas-fired pressure gassing plants intended for the use of a concentrated coal dust stream with oxygen, and since foreign burners are not accessible for comparison, the base objects selected were coal dust burners cyclone firing, with regard to its con-

~ 11 -

the apparatus for the pulverization of coal dust under pressure analog apparatus, are installed (Ju. L, Marsak "combustion plants with vertical cyclone chambers", linergöizdat, 1966, page 60, Figures 2 - 3a). Sine cyclone firing is installed in a liquid slag boiler of the Zakamsk thermal power plant (Perm region).

Since in the base object in the zone of intensive mixing at most 16 % of the oxidant (air) are enforced, the degradation process is greatly delayed. At the time of exit from the furnace, it is only 90 % complete. In addition, it was found during operation a slagging of the burner,

Examinations of the model of the proposed pulverized coal burner in a reactor with a capacity of 100 kg / h showed that the mixing process and the reaction process of the oxygen take place in a very short section and practically the entire reactor volume is used for the gasification process. This makes it possible to obtain a high-quality gas with a completeness of the process of 97 to 98%. In this case, no slagging of the burner was found in all experiments carried out.

Claims (2)

iSrfindungsansprttchi " 1. pulverized coal burner, consisting of a housing, a in
its central axis built-in channel for the supply of coal dust, arranged on the periphery channels for the supply of the oxidant with outlet nozzles, which at an angle
directed to the burner axis, characterized in that to increase the reliability of the operation and to improve the quality of the generated
Gasification gas of the burner is provided with a nozzle for supplying the steam and a nozzle for the exit thereof and the axis of the outlet nozzles
the channels for the supply of the oxidant
in the direction of the tangent of the base circle with the radius r: 0.5.R-r-0.8.R wherein: R - radius of the outlet opening of the channel for the Feeding the coal dust, wherein the distance ε between the centers of the outlet openings of the channels for the supply of the oxidizing agent and the pulverized coal lies in the range: R f I < § - R f 5. where: d - diameter of the outlet openings of the channels for the supply of the oxidizing agent, 2. A method for operating the pulverized coal burner according to item 1, characterized in that the mixture of the oxidizing agent is carried out with the coal dust in the stream of water vapor containing 6.5 to 9 _S 5 vol. -% oxygen. For this 2 sheets of drawings