KR20010053453A - Burner - Google Patents

Abstract

A description is provided of a burner (1) for introducing solid, liquid and/or gaseous fuel into a burning zone of a kiln, such as a rotary kiln for manufacturing cement clinker or similar products, which burner (1) comprises one or several substantially concentric pipes (2, 3, 4, 7) for conducting fuel and primary air, where the outermost pipe may comprise a refractory lining (12) to protect the burner against the hot kiln atmosphere. The burner is distinguished in that it comprises a turning means (21) by means of which at least the outermost pipe can be rotated about the longitudinal axis of the burner. It is hereby obtained that build-up of deposits on the upper side of the burner during operation can be avoided, and that the abrasion and radiant heat arising from the product flow will be evenly distributed across the entire circumference of the burner.

Description

Burner {Burner}

From the PCT / EP98 / 00145 owned by the applicant and the contents deemed to be included herein, burners of the kind described above are known.

For example, when using this type of burner in a cement making furnace where the air in the furnace often contains a lot of dust, it is found that deposits form very often on the upper side of the outer pipe of the burner near the sharp end. Can be. Within a few hours, these deposits will consist of clinker dust, inherently partially dissolved, stacked several meters high and stacked into pyramidal mountains. The deposits cause operational problems because they partially block the air nozzles, changing the direction and shape of the flames, in which the flames can affect the internal lining of the furnace, potentially using linings. It can greatly shorten the life. In the case of a large amount of deposit as described above, the burner pipe is subjected to excessive stress load which can cause the burner to fail.

As is well known, the above-mentioned problems can be solved through the regular removal of deposits. To date, there has been a standardized method of manually removing deposits using long tubular lances equipped with nozzles for injecting water at high pressures of about 300 bar. Typically, the lance inserted through one of the observation holes in the furnace lid should be in intimate contact with the deposit. When a water jet impinges on the sediment, high temperatures cause it to explode, causing the sediment to collapse.

The method described above involves a number of disadvantages: the violent vapor explosion presents a risk of injury to the operator, which means that the operator must have the necessary protective equipment, and the sediment typically has a length of 8 to 10 m. Since it is formed at the sharp end of the burner pipe, it is not easy to move a long lance through a small observation hole, and in many cases two people are required to operate the lance. Since the waterjet can inadvertently hit the lining instead of the sediment, there is a clear concern that it will damage the fire resistant lining of the burner pipe. To ensure the effectiveness of this method, sediments should be removed very often at intervals of two or three hours or less, which can be very time consuming.

Another approach that has been attempted is to install a permanent water lance in the burner pipe, which eliminates the risk and time-consuming manual operation, but this method is applied when the waterjet impact is applied over a wide area. Only when effective removal of the deposit can be achieved has been found to be unsuitable for use.

Finally, a third method is described in German Patent Application No. DE-19628487-A1, wherein the burner described in this application has a plurality of nozzle openings in the axial and radial directions with an additional external pipe at the sharp end thereof. The pipe is connected to a pneumatically actuated air blaster, and the deposits can be removed as intended by operating the air blaster at regular intervals, but this method cannot remove all deposits, just a nozzle. Only deposits placed very close to the opening can be removed.

The present invention relates to a burner for injecting solid, liquid or gaseous fuel into a combustion section of a furnace, such as a rotary furnace, for producing a cement clinker or similar product, which burns fuel and main oxygen. One or more generally concentric pipes are provided, with the outermost pipe having a fire resistant lining to protect the burner against air in the hot furnace.

1 is a partial side cross-sectional view of a burner according to the present invention,

2 is a cross-sectional view of the front part of the same burner.

It is an object of the present invention to provide a burner capable of removing deposits without having the disadvantages described above.

According to the invention, this can be achieved by a burner of the type mentioned at the outset, characterized in that it is provided with rotating means such that at least the outermost pipe can be rotated around the longitudinal axis of the burner.

In this way, since any dust deposits can be removed when the pipe rotates, the formation of deposits that accumulate on the upper side of the burner during operation can be prevented. Another important advantage of this method is that friction and radiant heat, which are usually caused by the flow of product which adversely affects the lining on the lower side of the burner, can be evenly distributed across the entire outer circumference of the burner due to the rotation of the pipe. This extends the service life of the burner, improving the working factor of the furnace.

The rotating means may be in any suitable form, but preferably has a mechanical structure such as, for example, a toothed gear. This rotating means can be operated manually or by using a remotely controlled motor.

If the rotary device is motorized, the motor should be suitably set to a rotational speed in the range of 0.25 to 5 revolutions per hour, preferably 1 revolution per hour.

In the most basic construction, the burner has only one pipe for delivering fuel and main air, but it is preferred that the burner has a burner pipe which interacts with one or a plurality of inner pipes located concentrically with the burner pipe. However, the pipes form a plurality of annular ducts that deliver and inject fuel and main air separately. In this embodiment of the burner according to the invention, at least the outermost pipe is rotatable about the longitudinal axis of the burner, but the burner can also be formed to be able to rotate around the longitudinal axis.

In a preferred embodiment, the burner has an envelope pipe arranged concentrically around the burner pipe, in which at least the envelope pipe is adapted to be able to rotate about the longitudinal axis of the burner.

When the burner is equipped with an outer pipe, a part of the main air flow can be induced through a gap provided between the burner pipe and the outer pipe to cool the outer pipe. The air flow through the burner pipe and the shell pipe is preferably composed of 2 to 4% of theoretically required combustion air flow.

Moreover, the envelope pipe may have holes for diverting the injected air flow which may contribute to limiting the amount of dust to accumulate on the burner.

The burner may also have one or more burner lances for delivering and injecting liquid or gaseous fuel and one or more pipes for delivering and injecting supplemental fuel which is a solid.

The invention will now be described in more detail with reference to the schematic drawings.

1 and 2 show a burner 1 which is designed to mix and combust oil and pulverized coal in a furnace such as a rotary furnace for producing cement clinker or similar products, which burner 1 is of a known structure. A separate lance, not shown, is provided with a central protective pipe 2 installed to spray and deliver fuel oil.

Two pipes 3, 4 are formed concentrically around the secondary pipe 2 to form an annular duct 6 therebetween that delivers and injects a mixture of pulverized coal and air. In order to cool the oil lance not shown and to protect it from dust, a small amount of the total main air flow can be delivered and injected through the gap between the pipe 3 and the protective pipe 2. In the addition of the protective pipe 2, one or more pipes for supplying other supplementary fuel can be inserted into the pipe 3.

A burner pipe 7, which forms an annular duct 9 which carries the remainder of the main air stream in relation to the pipe 4, is arranged concentrically around the pipe 4.

The outermost of the burner shown is provided with an outer pipe 11, which has a fire resistant lining 12 on the outside and is supported at the foremost end by a spacer 13. do. Inside the outer pipe, there is a guide ring 15 which is placed correctly with respect to the spacer. The rear end of the pipe 11 is supported by a roller 19. This pipe 11 can be rotated by the toothed gear 21. At the position where the outer pipe is inserted through the furnace wall 23, there is a closing plate 25 with a spring, which allows the outer pipe 11 to rotate and prevents leakage of false air. . In addition, the spring attached to the closing plate 25 allows the guide ring 5 described above to lie correctly with respect to the spacer, so that the outer pipe is fixed in the axial direction irrespective of thermal expansion in the longitudinal direction.

The burner pipe 7 has a plurality of perforated holes 31 which allow a small amount of the main air flow to be introduced into the gap 33 between the burner pipe and the outer pipe for cooling. This cooling air stream, which typically consists of 2 to 4% of the theoretical combustion air flow, should be directed backwards through the gap to minimize the inlet of cooling air into the original furnace to a practical limit. Preferably, the sheath pipe 11 may be provided with a plurality of holes 35 for diverting air through fire resistant linings.

During operation, the formation of deposits in the shell pipe can be prevented manually or by rotating the pipe using toothed gear 21 using a mounted motor not shown. The speed of rotation should allow the pipe to rotate at least one full revolution per hour. Rotation may occur at a constant or irregular rotation speed.

According to the present invention as described above, it is possible to regularly remove the deposits stacked in the burner with a rotating means, it is possible to obtain the effect of reducing the work risk and time and labor.

Claims (10)

Solid, liquid or gaseous fuel is introduced into the combustion section of a furnace, such as a rotary furnace for manufacturing cement clinker or similar products, with one or more concentric pipes (2, 3, 4) actually delivering fuel and main air. In the burner (1), the outermost pipe having a fire resistant lining (12) to protect against air in a hot furnace, The burner, characterized in that it comprises at least the outermost rotating means (21) so that the pipe can be rotated around the longitudinal axis of the burner. 2. The burner of claim 1, wherein the rotating means is mechanical means, for example in the form of toothed gears, and is operable by a motor that can be manually or remotely controlled. 3. The burner of claim 2, wherein the motor is set at a rotational speed within a range of 0.25 to 5 revolutions per hour, preferably about 1 revolution per hour. 4. A burner pipe (7) according to claim 3, comprising burner pipes (7) integrated with one or a plurality of inner pipes (2, 3, 4) located concentrically with the burner pipes, which pipes deliver and inject fuel and main air separately. Burner, characterized in that to form a plurality of annular ducts. 5. The burner of claim 4, wherein the entire burner is configured to rotate about a longitudinal axis of the burner. 6. An outer shell (11) according to any one of the preceding claims, having an outer shell (11) arranged concentrically around said burner pipe (7), at least the outer shell pipe being at least about the longitudinal axis of the burner. Burner characterized by being able to rotate. 7. The burner as claimed in claim 6, wherein a gap (33) is provided between the burner pipe (7) and the outer pipe (11) to guide a part of the main air flow to cool the outer pipe. 8. The burner of claim 7, wherein the air flow induced through the gap (33) between the burner pipe and the outer pipe consists of 2 to 4% of the theoretically required combustion air flow. 9. The burner as claimed in claim 8, wherein the outer pipe (11) is provided with holes (35) for diverting incoming air flow. 10. The burner of claim 9, comprising one or more burner lances for injecting and delivering fuel that is liquid or gas, and one or more pipes for injecting and delivering supplementary solid fuel.