DD212786A1 - DEVICE FOR COMBUSING DUST-FUSED FUELS - Google Patents

Abstract

The invention relates to a device for the combustion of Staubfoermigen fuels, which can be used in particular on boilers, but also on lined with refractory materials Brennraeumen. As a result of the achievable high heat density u. good automatability, it is preferably as a substitute f. previously used with fuel oil or gas burner suitable. The essence of the invention is that the secondary air flow with a the design cross section of the inlet channel corresponding and variable by a valve disposed in the inlet channel variable speed tangentially enters the housing so that a stable swirl flow with inner recirculation zone, even without complex spoiler with comparatively complicated internal structure especially in twist adjustability, builds.

Description

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Title of the invention -

Apparatus for burning pulverulent fuels

Field of application of the invention

The invention relates to a device for the combustion of pulverulent fuels with the even in narrow and highly cooled combustion chambers, as they represent in particular the flame tubes in boilers, a homogeneous rotating flame can be generated. The device is also in combustion chambers, which are lined with refractory materials, used. As a result of their high degree of automation and heat density, the device can be used in particular as a replacement for burners previously operated with fuel oil or gas.

Characteristic of the known technical solutions

In boilers and combustion chambers of industrial heat application systems are increasingly used both to increase performance over conventional grate firing as well as the substitution of fuel oil or gas devices for burning pulverulent fuels that produce rotating flames with high heat density and technically solved several times.

So also in a burner according to WP 0153 911, in which the swirl momentum of the secondary air flow is generated by an axially fixedly arranged around the fuel dust tube swirl vane ring,

In patent DE-AS 29 33 060 such a swirl trough crane is adjustable angeord.net.

According to patent DE-PS 31 06 824, the swirl momentum is achieved by the combination of a swirl device on the burner mouth with fixed blades, which are arranged at an angle of 25 ° to 35 ° to the burner axis.

As a deficiency in the aforementioned solutions is recognized that they require to achieve the necessary swirl impulse consuming louvers, which causes a relatively large volume and an associated increased cost of materials for the burner and a relatively complicated internal structure of the spoiler requires in particular with swirl adjustability.

Furthermore, it is recognized that the burner with swirl vane or, air guide at the same power rating require a relatively high pressure for the secondary air flow.

Object of the invention

The invention has the aim of providing a device that offers favorable conditions for optimal combustion of different pulverulent fuels with a comparatively small volume and material expenditure as well as with the simplest construction and production costs. Compared with comparable devices, the secondary air-side pressure requirement in the nominal load range is to be lowered, and the insensitivity to control interventions in the fuel and / or combustion air flow is to be increased. This creates the prerequisites for improved automation with frequent on / off operation and high load change speeds.

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Explanation of the essence of the invention

The essence of the invention is that the secondary combustion air is introduced tangentially into the housing (4) through a correspondingly formed inlet channel (2). The introduction takes place on one side in the through the housing (4) and the central tube (5) formed annular channel (6), whereby the secondary combustion air receives a swirl pulse, the strength of which by the dimensions of the inlet channel (2) dependent entry velocity is determined To adjust the flame to predetermined combustion chamber geometries or applications or different fuels required regulation of the degree of swirl is carried out by the erfindungsgeraäße valve (?) in the inlet channel (2).

Due to the found solution for swirl generation can be dispensed with the elaborate spoiler and possibly necessary adjustment, which leads to a material and space-saving and cost-effective. Design and requires a lower pressure of the secondary air flow.

To regulate the necessary for optimal combustion, according to the amount of fuel supplied, secondary air flow to the burner a per se known throttle valve (8) is connected upstream.

According to the invention, a premix traction is formed in the housing (4) in that the central tube (5) serving to introduce the pulverized fuel / primary air mixture (9) terminates before the diffuser (7). The tangentially entering at high speed secondary air causes a rotating flow with a strong inner, brought directly into the premixing chamber recirculation, die.zu a good premix of the fuel dust-primary air mixture with the secondary air before entering the diffuser (7), and a thus more uniform distribution of the fuel dust in the combustion air leads, resulting in

the characteristic short rotationally symmetric flame is formed.

Due to the fact that the entire supplied combustion air is directly involved in the combustion, comparatively higher combustion technology efficiencies, _{r can be} achieved.

The solution found, compared to others'. Although comparatively shallower performance characteristics require an exact power adjustment, on the other hand they lead to a greater insensitivity to rapid load changes, as they occur when using fast-acting actuators, and thus allows better automation.

Embodiment;

The device will be explained in the following embodiment with reference to Figures 1 and 2. ,

The use of solid fuels instead of fuel oil or gas in heat generation plants or industrial furnaces requires the use of improved or new burner systems. Here, swirl or vortex burners in which dusty fuels are used, in the foreground because comparable heat flux densities can be achieved with them. The solution according to the invention represents such a burner, which is due to its teohnisch simple solution very material, cost and space-saving.

As a field of application for this device, in particular, those boilers are to be considered, which were originally designed for solid fuels by means of grate firing, later converted to the use of liquid fuels or were built up as new systems based on fuel oil or gas. The thereby used oil burner systems with low

Construction volume require "when you switch to coal dust such burners that fit well due to small external dimensions in existing plant configurations and cause a small Ums partial expenditure.

At a thus converted to lignite briquette dust boiler steam generator with a capacity of 5.2 t / h, the inventive solution for burning the fuel dust was used.

_r -. _% The fuel dust is supplied by carrier air, which is also part of the total required combustion air as fuel dust-primary air mixture (9) the burner in accordance with laid out pipelines with safety-related! .Lindestgeschwindigkeiten and passed in the central tube (5) to the premixing chamber. The necessary secondary air (1) is as so-called forced air with a design the cross section of the inlet channel (2) entspre-.,. ohenden speed, tangentially into the annular channel (6) formed by the housing (4) and the central tube (5), whereby the secondary air (1) receives a strong pressure pulse. The degree of swirl can thereby be adjusted by a control flap (3) arranged in the inlet channel (2).

() match conditions determined by adapting the flame to given combustion chamber geometries and uses or fuels. The regulation of the necessary for the optimal combustion management secondary air flow takes place with a known, before the inlet channel (2) arranged throttle valve (8). The secondary air mixes in the pre-mixing chamber with the Brennstaub-Primärluft Gemiseh both by the Brall of the secondary air as well as by sieh see .aufbauende recirculation in the flame, so that a very homogeneous distribution of coal dust enters the combustion air.

The ignition of the fuel-air mixture takes place in the combustion chamber (10), for example by means of known, with Die-

self-fuel or propane fueled pilot burner. As a result of the high swirl momentum and the good mixing of the pulverized fuel and air mixture, a short rotationally symmetric flame characteristic of the solution is formed, which is regulated and automatically controlled to the extent that the same degree of automation occurs as in oil-fired plants.

Claims (2)

claims 1, apparatus for combustion of pulverulent fuels, characterized in that the secondary air flow (1) with a the design cross section of the inlet channel (2) and by a in the inlet channel (2) arranged special valve (3) variable speed tangentially in the from the housing ( 4) and from the central tube (5) formed annular channel (6) occurs, that builds up a stable swirl flow with inner recirculation zone in the combustion chamber (1O). 2, device according to Ί, characterized in that in the housing (4) by the considerably before the diffuser (7) ending .Central tube (5), a premixing zone is formed, which up to the diffuser (7) Rüokführende design of the recirculation zone and an improved Mixture between fuel dust and combustion air while minimizing the combustion air flow causes. - For this 1 sheet drawings -