DE3115083A1 - Boiler - Google Patents

Abstract

The boiler (1) contains a gas flue (2) with, arranged therein, wall-cooling screens (3) consisting of pipes. The wall-cooling screens (3) are connected to an upper (4) and a lower (5) collector. In the gas flue (2), partition walls (11) consisting of pipes are arranged, which are connected to autonomous upper (12) and lower (13) collectors. These autonomous collectors (12 and 13) are respectively connected to the upper (4) and the lower (5) collectors of the wall-cooling screens (3). The partition walls (11) consist of pipes which are arranged at a distance from one another of 4 to 20 outside diameters of one of the pipes which form the partition wall (11). Each partition wall (11) is designed in the form of a bow, the ends of which are bent off towards the side of the wall-cooling screens (3). Each autonomous upper (12) and lower (13) collector is likewise bent off towards the side of the wall-cooling screens (3). <IMAGE>

Description

P 85 2Ö0-M-61 April 14, 1981

DESCRIPTION I / Ho

The present invention relates to boilers and, more particularly boilers for generating steam _a i _s fuels and waste-heat boilers in which flue gases of various technological processes are cooled.

The present invention can be used in the planning and construction of boiler heating surfaces for large power plant boilers in those solid fuels with a high ash particle content are burned, as well as for waste heat boilers in which process gases from industrial furnaces in the iron and non-ferrous iron industry and be cooled in the chemical industry.

The invention can also be used in heat exchangers of any desired purpose in which gases with an ash particle content of over 50 g / nmr have to be cooled.

The present invention can, however, be used most effectively in waste heat boilers in the iron and steel industry and the chemical industry, in which process gases with an ash particle content of more than 50 g / nn are used need to be cooled down, though. the ash particles to it tend to lead either to the wear of metal walls of the heating surfaces or not insignificant deposits on them that affect the "effectiveness of heat transfer" can.

In industry, waste heat boilers whose heating surfaces are designed according to the ^M tube-in-tube type are known; they are also called smoke tube waste heat boilers - or

Cool flotation gravel. The gases flow in the pipes at high speeds of 15 to 20 m / s. When moving of the gases with such velocities will be a

( Ensures the effective heat transfer between the hot gases and the pipe surface, the high gas velocities cause rapid wear of the pipes due to abrasive ash particles and thus frequent disruptions in boiler operation -in-pipe "-type heating surfaces to avoid, especially at their bin and outlet ends,

ceramic or metallic contactor insert pieces are placed in the inner tubes, which often have to be replaced while the boiler is in operation. In addition, it must be taken into account that if there are fluctuations in the gas temperature at the inlet to the heating surface or if the composition of the roasting material changes, the properties of the ash particles in the gas flow will also change. ^Be * increase in gas temperature to over 900 ⁰ C or with an increase in - ^ rsenic and selenium

The ash particles, for example, are retained in the roasted sulfur gravel a condition that leads to the fact that on the pipes, especially at their entry and exit, sticky deposits form, which rapidly increase the aerodynamic Resistance to the gas flow and, as a result, emergency shutdowns of the boiler to clean the heating surfaces. This reduces the effectiveness of the heat transfer to a significant extent.

The strength of the "tube-in-tube" type heating surfaces is inadequate, for the reason that due to its special design features on the welded parts of the

j NACHG EREtCHTf I * Ί 'III' l "I \ 31 1 5 Q 8

-ein- and outer pipes with the collector during operation high temperature original stresses occur, which can be attributed to different temperatures of the inner and outer pipe wall and to the different length of this bore. This fact, in turn, limits the use of such heating surfaces in the construction ^of waste heat boilers for

great linear performance because of the length of the inside and outer pipes must be greatly enlarged. In addition, the measures to remedy the temperature difference close the Inner and outer pipe walls are hit by heating the outer pipes, dis with the wear and the pollution problems related to heating surfaces.

Heat recovery boilers of this type require a high level of metal

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wall for making the heating surfaces / are complicated in the production as well as the repair and monitoring of the welded joints at the welding points of the pipes with the Manifolds.

Waste heat boilers are also known, which e.g.

Cooling of the roasting furnace can be used when roasting pebble-sulphurous gases, which are very dusty, and the heating surfaces of which are made of pipes of small diameter. The gases flow around the pipes from the outside, the pipes are in a room enclosed by heating surface pipes. The pipes are arranged in space with an inclination: _{to the} horizontal and place one of the gases across or in one

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certain angle / mspül end snake surface. In such Boilers are provided between the bundles of inclined pipes, gaps around the heating surfaces wait during the operation and repair of the boiler

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to be able to. Maintenance access points are located in the columns, which is an additional source of cold air access represent from the outside. Because of the gaps between the tube bundles, the boiler in question is not sufficient compact design. ^ aIIs in the pipes. more natural Circulation is used, it turns out that its reliability is low, and to increase it one has to build in a large number of circulation downpipes, which the Complicate the boiler in its execution and the tube expenditure and increase the labor costs in the manufacture of the boiler.

The heat transfer takes place in such heating surfaces at high gas velocities, preferably by convection and the heating surface itself has a raised surface because of the gas flow around the tubes in the transverse direction Susceptibility to wear and tear and contamination.

In the industry, boilers are also known that cool a Gaüsug with a wall arranged therein and made of pipes which are connected to an upper and a lower collector of these wall cooling screens and located in the gas flue Bulkheads contain pipes that are connected to the autonomous upper and lower headers, each with the connected upper and lower collector of the wall cooling screens are. Each bulkhead is made of straight pipes, while the autonomous upper and lower headers are horizontal are arranged.

In view of the fact that the autonomous collector of the bulkhead walls have a high rigidity and the pipes are designed as straight tubes, arise during the thermal expansion of the tubes at their connection points with the

Collectors of the bulkhead walls as well as on the connecting parts of these lastixen with the collectors of the wall cooling screens additional tensions, which lead to a decrease in strength in ^the construction. Sin of such boiler also has still the disadvantage of larger dimensions, for it comes with a horizontal arrangement of the autonomous collectors of the ^above chottenwände in fact minimal technologically comply dependent distances, between the welds at the points where the Eohre the Scots walls to them associated autonomous collector are connected, as well as between the weld seams at the points where the autonomous collector of the bulkheads are connected to the collector of the wall cooling screens and the pipe next to the wall cooling screen is connected to its autonomous collector. This leads to an increase in the overall dimensions of the boiler in the direction perpendicular to the plane of arrangement of the bulkhead walls. ■ The horizontally arranged autonomous collectors of the S _c hpttenwände cover also to a considerable extent the flow section for gases, whereby the gas flow speeds increase locally and clogs the sintering and Austrittsbereiohe the boiler locally and dirty. In an effort to avoid local increases in gas velocities, attempts were made not to arrange the bulkhead walls on the entire circumference of the radiant heating surfaces.

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Order of the bulkheads disturbs) the aerodynamically uniform Gas flow along the heating surface and also leads to local wear and contamination.

The purpose of the present invention is to remedy the aforementioned shortcomings.

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1 NACHÖEREIOHTJ

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The invention is based on the object of creating a boiler with a structural design of the heating surfaces that enables an effective cooling of heavily dusty gases (with a dust content of over 50 g / only), with the occurrence of a heat transfer, preferably by radiation, when the gases flow on the heating surfaces at low speeds (2 to 5 m / s), at which there is practically no wear on the pipes, the heating surfaces are less soiled with ash particles and the boiler itself can be built compactly.

This object was "achieved with a boiler that cools a gas flue with a wall arranged therein from pipes which are connected to an upper and a lower header of these wall cooling screens and which contains bulkheads made of pipes in the gas flue, which are connected to upper and lower autonomous headers are connected, which ^ are each connected to the upper and lower collector of the wall cooling screens,

/ are formed , according to the invention the bulkhead walls are made of corrugated

dsr are arranged at a distance of 4 to 20 outside diameter of one of the pipes of the bulkheads and each bulkhead is designed in the form of a bracket, the linden trees are bent towards the side of the wall cooling screens, and each autonomous upper and lower collector is bent towards the same side.

Because the bulkheads in a considerable Are arranged at a distance from each other, there are favorable conditions for effective heat transfer Radiation from the hot gases to the pipes of the bulkheads. This is due to the fact that the thickness of the

Radiation layer of a gas volume enclosed between the adjacent bulkheads is enlarged. In addition, this fact also favors a reduction in the flow rate of the gases to be cooled and thus the erosion wear of the pipes and reduces their pollution by ash particles. The latter is explained by the fact that the asoh particles adhere so weakly to the pipe surface at low speeds that they
<after reaching a certain contamination layer thickness

begin to fall off the pipes under their own weight, and the stabilized coating layer that has remained behind from the Pipe surface in a relatively simple way of cleaning can be easily removed. If necessary, there is a method that consists in passing the pipes through

mechanical impact periodically to vibrate bring.

The bow-shaped bulkheads, which are arranged at a certain distance from one another, allow effective cooling of the heavily dusted gases with a dust content of over 50 g / nm. With the presence of the bulkheads, which are arranged at a certain distance from one another and are designed as brackets with the ends bent towards the side of the wall cooling screens, as well as with the presence of the autonomous upper and lower collectors with the also bent towards the side of the wall cooling screens On the other hand, there is the option of choosing minimal distances between the pipes of a bulkhead wall and making the boiler compact.

It is advantageous to have the bulkhead walls in the entire hollow

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Space de a throttle cable to be arranged as evenly as possible.

This ensures that the pipes of the bulkheads evenly distributed in the cavity of the throttle cable and from the gases are evenly flushed around and the turbulence of the gases is eliminated, which leads to the intensive formation of. ' Partial ash deposits contributes.

Bs is advantageous when a portion of the bulkhead wall pipes or · are all connected to each other by metal plates ⁱⁿ O ^.

This rules out an overflow of gases between the pipes, reduces the turbulence of the gases, reduces the pollution of the pipes with ash particles and continues reduces the pipe expenditure for the production of the heating surfaces.

The invention is described below with reference to

the attached drawings:

Fig. 1 in a schematic representation of a boiler in Longitudinal section,

fig. 2 shows a section along the line U-II of Fig.l,

3 shows an assembly A from FIG. 1 (on an enlarged scale).

The boiler 1 (Fig.l) contains a gas flue 2 in which Wall cooling screens 3 are housed from tubes. These wall cooling screens 3 are attached to an upper 4 and a lower 5 Collectors connected.

These collectors 4 and 5 are with a drum 6 means Downpipes 7 and riser pipes 8 connected.

The throttle cable 2 has a fall area 9 and a Climbing area 10. In the climbing area 10 of the throttle cable 2, bulkhead walls 11 made of pipes are accommodated. Any of these

Bulkheads 11 is formed in the form of a bracket. this allows the choice of minimal distances between the pipes of each bulkhead wall 11 and a compact design of the Boiler 1.

In the example given, the bulkheads 11 are in Increase area IO of the throttle cable 2 housed. The bulkhead walls 11 can, however, also in the fall area 9, i.e. evenly in the entire cavity of the throttle cable 2. This ensures that the tubes of the bulkhead walls 11 in The cavity of the throttle cable 2 is evenly distributed and the gases are evenly flushed around it. In addition, the turbulence of the gases that otherwise contribute to the intensive formation of ash particle deposits.

The partition walls 11 are arranged at a distance "s ^M (Pig. 2) from one another, which is 6 outside diameters of one of the pipes in the partition walls 11. Although in the given example the soot walls 11 are arranged at a distance" s "from one another, the 6 outside diameter one of the tubes in the bulkhead walls II is, this distance "s" can be 4 to 20 outside diameter of one of the tubes of the bulkhead walls 11. If the distance "s" is less than 4 outside diameter of one of the tubes in the bulkhead walls 11, one must with Rise in gas velocities, decrease in heat exchange due to radiation and increase in pollution of the pipe surfaces and wear and tear on the pipes. If one of the pipes in the bulkhead walls 11 exceeds the value of 20 outside diameters by the distance "s", the outside dimensions of the boiler increase * 1 very.

The bulkhead walls 11 are made of Ronren small diameters

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Knife manufactured and open into each partition wall 11 assigned = upper 12 and lower 13 (Fig. 3) collector a, which in turn in the upper 4 and the lower 5 collectors of the wall cooling screens 3 open. The collectors 12 and 1 $ (Fig.l) of the bulkhead walls II have variable Slope to the gas flow direction on and .the sections, to which the pipes of the bulkhead walls 11 are connected, are towards the side of the wall cooling screens 3 turned. This will block the passage cross-section for gases in the plane that runs normal to the plane of the bulkhead walls 11, reduced to a minimum. this in turn has the consequence that the gas flow rates are low, which contributes to the fact that the pipe wear is reduced and the strength of the Pipes formed deposits decreases. A larger part of the surface of the bulkhead walls ü is from the gas flow in the longitudinal direction washes around and this affects the pipe sole and reducing ear pollution. That the sections the collector 12 and 13 of the bulkhead walls 11 are arranged inclined to the side of the wall cooling screens 3, creates the Conditions for that, in comparison to the other arrangement of the collector 12 and 13 of the bulkhead walls 11, the passage cross-section a minimum value can be set for gases. This eliminates the influence of the strength requirements to collectors 12 and 13 on the choice of

ςββ would stand between the pipes of the bulkhead walls 11 and i would have a relatively greater freedom in the choice of the distances between the pipes in the bulkhead walls 11.

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enough. The pipes in the Schot tenssandsn 11 can be arranged at any distance from each other (from close together to a distance of several pipe diameters) and must first be separated at the connection points to the autonomous collectors 12 and 13 at distances that are determined by the strength conditions the collector 12 and 13 of the ^ bulkhead walls II result. Thus is achieved that with minimal outer dimensions of the boiler 1 of the utageschlossene of the wall cooling screens 3 Schotten space is ^ hott walls with S _G II densely filled in turns.

To the kettle 1 G _a se be able to supply ^from a not shown in the drawing furnace, the boiler 1 with a Bintrittskammer 14 and an outlet chamber 15 for gases is provided, and has in its lower! Part for transferring the gas from the i ' all area 9 in the riser area IO of the gas train 2 has a bunker 16, which at the same time serves as a receptacle for the falling out of the gas stream and

. from the surfaces of the bulkheads 11 and the wall cooling screens 3 falling ashes are used.

In each partition wall 11 and each wall cooling screen 3 all tubes are connected to one another by metal plates 17. This eliminates the overflow of gases between the bores, the turbulence of the gases is reduced, the pollution of the pipes with ash particles and the pipe expenditure is reduced reduced for the production of the heating surfaces. There are however, other designs of the boiler 1 are possible in which only a part of the pipes in the bulkheads 11 through Spacer 17 is connected to each other or the tubes are not connected at all.

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If necessary, "by using the metal plates 17 between the pipes in the bulkheads 11 and Shield the wall cool 3. A high gas tightness of the boiler 1 brought about affecting the effective further processing of process gases has a positive effect. For example, the

Exclusion of air ingress from outside in the sulfuric acid production a dilution of the gases with air and ensures the maintenance of a high SO ₂ concentration and thus a higher sulfuric acid emission (H ₂ SO ^).

Bs is aiioh advantageous, namely for reasons that

manufacturing technology for the bulkheads 11, the latter from pipes of small diameter (as they are used for the production of serpentine surfaces of the boiler 1) produce and the diameter ratio of the pipes of the bulkhead walls 11 and their associated autonomous collection

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For 12 and 1 $ ϊ to choose at least 1 to 2, with smaller diameter ratios difficulties arise in a quality-appropriate welding of the pipes of the bulkhead walls 11 to their autonomous upper 12 and lower IJ headers.

For the manufacture of the boiler 1, common materials are used in boiler construction, namely boiler steels. the Metal plates 17 between the tubes can depending on the size of the heat flow can be made from a material of lower quality.

Ss is recommended for exhaust gases with an abrasive content Ash particles. Gas flow velocities of at most 5 ra / s to choose, while for exhaust gases with a content the gas velocities on sticky ash particles should be in a range of 0.5 to 5 m / s.

ORIGINAL BATHROOM.

A boiler of this kind is suitable for the cooling of gases from any high temperature to a temperature of at least 400 to 45O ⁰ C for a dust content of the gas stream in excess of 50 g / nm. That of the tubes of the 7 / andkühlschirme 3 umgeschlcssßS0. ^ Chnitt of G _a szuges 2 should be sized at most 5x6, with a further increase in boiler output by turning on a plurality of such G _a szüge 2, in other words, soloher by increasing the number of gas ducts 2 can be achieved. For cooling gases to a temperature from 900 to 950 ⁰ C it is recommended that the Scots room no Scots walls or bulkheads evaporator accommodate mm to use mit'einer Scots division of at least 1200th Such a constructive execution allows a reliable functioning of the heating surfaces of the boiler in conditions with a heavily dusty gas flow, eliminates the wear of pipes by abrasion particles, reduces the soiling of the heating surfaces, strongly reduces the strength of the coverings and thus creates favorable conditions for the cleaning of the Heating surfaces.

In individual cases, a highly effective boiler 1 can be created in which heavily dusty gases without the use of Special devices for cleaning the heating surfaces can be cooled »A high level of gas tightness of the can be achieved Boiler 1, a reduced amount of metal used to build the boiler 1, an extension of the life of boiler 1 between the heating surface cleaning and as a result the Increase in. . average number of hours worked of boiler 1, a growth in the annual average production of steam and technological sulfuric acid or

ORIGINAL

other products. The operational reliability of the boiler 1 increases overall compared to the known types of sow.

The operation of the boiler 1 according to the invention is the following.

The ash particles with strong dusty exhaust gases from a technological furnace are fed at a temperature from 800 to 1300 ⁰ C of arranged in the upper part of the Sallbereicb.es 9 des'Gaszuges 2 inlet gas chamber fourteenth The gases, which contain a large amount of fine ash particles, at least 50 g / nar, enter the fall area 9 of the gas flue 2. By cooling down in the fall area 9 of the gas flue 2, they give their heat to the tubes of the wall cooling screens 3 from and into the hopper 16 of the vessel 1, from where they are guided in the DEA Stetlgbereich 10 of the throttle cable 2 »the rabbit with a high Aschenteilchengehalt ⁰ C to a temperature of 600 to 800 cooled, wherein the ash particles lose their sticky texture whereupon the gases in the un-r direct part 10 of the Gaszugea 2 pass and be cooled there to a temperature of 400 to 450 ⁰ C, then currents ^ they men in the outlet chamber 15 and for further processing, for example, introduced into a contact reactor to move into the subsequent process. Sulfuric acid to be processed

While the gases durefc. the potash area 9 and the riser area 10 of the gas cable 2 flow, it happens that the _{Asohteileohen} contained in the gases partially fall out in the bunker 16 of the boiler 1 and partially see the ears of the wall cooling screens 3 and the Eofaren of the bulkhead walls II drop. The accumulated in bunker 16 of boiler 1

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Aehentelichen are periodically removed from the boiler. normal way of working. The drum 6 of the boiler is via the downpipes 7 (not surrounded by the gases)

Feed water supplied to the lower collector

5 of the wall cooling screens 3 flows in. From the collector 5 occurs the water in the autonomous collector 13 of the bulkheads and into the tubes of the wall cooling screens 3, where the gas heat through the drilling walls of the wall cooling screens 3 and the Partition walls 11 heated and converted into a steam-V / water mixture, which shields 3 and cool in the pipes of the wall the bulkhead walls 11 rising into the upper autonomous collector 12 of the bulkhead walls II and in the upper collector 4 of the Wall cooling screens 3 reached. In the upper collector 4 of the wall cooling screens 3 is the steam / water mixture from the top autonomous collectors 12 of the bulkhead walls 11 with the steam-water mixture from the drilling of the wall cool schir me 3 mixed and the resulting steam-water mixture thus formed enters the drum 6 via the riser pipes 8. In the drum 6, the steam-water mixture separates into steam and water, the steam being passed on to the consumer and the water is fed back into the downpipes 7, and the entire water cycle repeats itself,

Claims (3)

"" Ti, - · ■ - ·., «- ■. . ■■ T f.; .-. SP - Tt * YXadimir A. Zaitsev, Ing.
Belgorod / lJdSSR, taad 9 other applicants P 85 200-H-61 14. (W-. 1981 L / Ho KESSSL
Claims 1J boiler, containing a gas suction with arranged therein Wall cooling screens made of pipes which are connected to an upper and a lower collector of these wall cooling screens and bulkhead walls in the gas eye are made of pipes, which are connected to upper and lower autonomous collectors which are connected to the upper and lower header of the wall cooling screens, which means that y formed si ncJU die; draws that the bulkheads (il) from iionren / from ^ each other at a distance (s) of 4 to 20 outside diameter one of the bores that form the bulkhead wall (11) <that
is arranged utuT Each bulkhead wall (11) is designed in the form of a bracket, the ends of which are bent towards the side of the wall cooling screens (3), and each autonomous upper (12) and lower (13) collector is bent towards the same side. 2. Boiler according to claim!, Characterized by show that the soot walls (11) are almost uniform are arranged in the entire cavity of the throttle cable (2). 3. Boiler according to claim 1 or 2, characterized In each bulkhead wall (11) some of the pipes or all of them are connected to one another by metal plates (17) are connected.