FI87106B - Hot-water or steam boiler - Google Patents

Description

87106

HOT WATER OR STEAM BOILER HETVATTEN- ELLER ENGLAND

The present invention relates to a flue gas boiler, i.e. a steam or hot water boiler for recovering the heat contained in the flue gases or hot process gases as steam or hot water. The boiler comprises a convection section arranged in a substantially horizontal flue gas duct, in which water and / or steam pipes are arranged to pass from an upper chamber 10 above the convection section to a lower chamber below it.

In currently used flue gas boilers, water or steam pipes are generally connected to other upper and lower chambers of a horizontal cylinder, so-called upper and lower cylinders, or to several horizontal manifolds. In boilers using cylinders, the water pipes must be bent to a suitable shape before being welded to the circumference of the cylinder. Bending and fitting the tubes perpendicular to the circumference of the cylinder 20 is cumbersome. Rib or fin pipes cannot usually be used in boiler structures where the pipes have to be bent. However, from the point of view of heat recovery, fin or fin pipes would be advantageous. On the other hand, known boiler bases, in which it is already possible to use straight water pipes, require a large number of horizontal chambers or horizontal manifolds into which one row of water pipes can be welded per manifold. The known boiler structures are considerably cumbersome and expensive in this respect from a manufacturing point of view.

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The object of the invention is to provide a better and simpler water or steam pipe boiler structure in which the above-mentioned disadvantages are minimized.

It is a particular object of the invention to provide a boiler structure in which direct water or steam pipes can be used.

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It is a further object of the invention to provide a boiler structure for the heat recovery of flue gases in which fin or fin pipe structures can be used.

To achieve the above objects, the present invention is characterized in that the upper chamber of the convection section is formed of side walls, an upper end and a substantially planar horizontal lower end and is arranged on a horizontal flue gas duct, and that the lower chamber is formed of side walls, lower end and . In addition, the water and / or steam pipes are substantially straight along their entire length and fixed perpendicular to both the lower end of the upper chamber and the upper end of the lower chamber and adapted to pass through the gas passage perpendicular to the gas flow from the upper chamber to the lower chamber.

The boiler preferably has an upper and lower chamber with a steel plate structure, between which there are water pipes, which may be smooth pipes, fin pipes, fin pipes or other pipes suitable for heat transfer. A flue gas duct is arranged between the upper and lower chambers, in which the flue gas or some other hot process gas passes perpendicular to the water pipes. 25 Depending on the flue gas temperature, the walls of the flue gas duct can be a steel plate, a membrane pipe wall or some other heat-resistant material. Membrane pipe walls are formed of water pipes connected to each other by so-called lattaevillä. The walls may also be coated with refractory mass, masonry or similar steel plate protection.

The upper and lower chambers are preferably in the form of vertical shallow cylinders, the ends of which may be straight, convex or plate ends. The ends of the chamber are supported by support plates according to pressure vessel standards for the duration of the internal pressure.

3 87106 The shape of the ends is round if the chamber forming the convection part is in the shape of a conventional round cylinder. If the convection part so requires, the ends can be, for example, oval, elliptical or in the shape of a stretched circle. The ends can be formed, for example, by connecting semicircular parts to a rectangular plate. The upper and lower chambers are then of similar shape. The ends can also be square or rectangular.

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The boiler according to the invention is simple and inexpensive to manufacture. The solution according to the invention avoids cumbersome bending of water pipes and welding of bent pipes to the circumference of steam cylinders. Boiler 15 also does not require a large manifold network to collect water and steam from the water pipes. The solution according to the invention makes it possible to use rib tubes or fin tubes and thus to increase the efficiency of heat transfer.

The flue gas boiler according to the invention is mainly intended for the recovery and utilization of the heat contained in the flue gases. Heat is transferred through heat transfer surfaces to a heat transfer fluid, e.g. water in a district heating system. In a hot water or hot water boiler, heat is recovered as hot water and in a steam boiler as low pressure steam. With the steam boiler version, the necessary steam can be produced in a power plant or industry. The heat transfer medium can also be another liquid, e.g. so-called hot oil in low pressure systems.

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The source of flue gas is mainly the combustion of natural gas or fuel oil, for example in a gas turbine or diesel engine, the flue gas produced at a temperature of approx. 400 - 600 ° C is led to the boiler. Heat can also be recovered in the boiler from hot gases from other combustion processes or other processes, preferably at a temperature of at most 1000 to 1500 ° C. In the boiler, the gases are cooled to approx. 70 - 200 ° C depending on the composition of the gas or e.g. 4 87106 steam values. Temperatures can vary greatly depending on the process mentioned above.

In the steam boiler version, the upper chamber acts as a steam space, from which the produced steam is led to the application. The upper connection is equipped with the necessary connection connections for safety devices, etc. The upper chamber is also fitted with other conventional necessary steam cylinder equipment, manholes, droplet separators, etc.

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Between the upper and lower chambers there are downcomers, which may be one or more for conducting water from the upper chamber to the lower chamber. Some of the water pipes can also act as downpipes either outside or inside the flue. Usually there are 15 downpipes outside the flue gas duct. In the steam boiler, saturated water flows from the upper chamber to the lower chamber, from where it rises along the water pipes under the influence of the flue gas heat, while partially evaporating into the upper chamber. The cycle takes place in a continuous natural cycle due to the density of water and steam 20.

The water to be heated in a hot water or hot water boiler is usually introduced into a lower chamber, where the incoming water, depending on the amount of water, is distributed by water guide plates to flow into pipes on the flue gas duct outlet side. The water pipes in the water boiler are preferably divided in the flue gas flow direction by water guide plates into two or more groups of equal size. Water flows upwards in every other group of pipes and downwards in every other one. The arrangement provides a partial countercurrent flow of water and flue gas. The upper chamber has the same water guide plates as the lower chamber. The heated water is usually led from the upper chamber of the boiler to the application. Water can also pass through the water pipe from the lower chamber to the upper chamber at once.

35 The distribution of water pipes in the flow direction of the flue gas can be square or triangular or something else depending on the solids content of the gas. If the pipes are divided in a triangular section or arranged in an interleaved manner, the flue gases have to change direction of the ground as they flow past the pipes, which advantageously affects the heat transfer. The pipe spacing used and the pipe size depend on e.g. boiler power and gas volumes.

In the boiler according to the invention, the flue gases can pass through the entire water pipe package at once. The pipe package can also be divided in half in the middle of the spacer so that the flue gases run in one direction on one side of the spacer and in the opposite direction on the other side of the spacer and exit from the same side of the pipe package as they came from the boiler.

The invention will now be described in more detail with reference to the accompanying drawings, in which Figure 1 schematically shows a cross-section of a vertical water pipe boiler according to the invention, Figure 2 shows a section of Figure 1 along line A-A and Figure 3 shows an axonometric view of a boiler according to the invention.

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Figures 1 and 2 show a cylindrical steam boiler 10 according to the invention. The walls of the steam boiler are thermally insulated. The steam boiler consists essentially of a cylindrical convection section 12, a low cylindrical upper chamber 14, a low cylindrical lower chamber 16, water pipes 18 and a flue gas duct 20. The flue gas duct walls 22 may be .water pipe ice-30 dytite membrane pipe walls.

The upper chamber 14 is formed of vertical side walls 24, an upper end 26 and a lower end 28. The side walls are in the shape of a conventional cylinder. In other embodiments of the invention, the sidewalls may form an elliptical or stretched circular vertical cylinder. The upper end 26 and the lower end 28 of the cylinder are horizontal and planar in the boiler shown in the figure.

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The water pipes are attached to the openings 30 in the planar lower end 28 of the upper chamber. The lower end is quite straight in the boiler shown in the figure, but can of course be somewhat convex.

5 However, it must be possible to attach the water pipes to the end in such a way that they do not have to be bent. The upper end of the upper chamber is shown in the figures as completely planar, but may be slightly convex accordingly.

10 A support plate 32 is further arranged in the upper chamber to support the cylindrical structure. The support plate has openings 34 through which water and steam can move freely in the upper chamber. Steam is removed from the upper chamber through a pipe opening 36. The feed water is introduced into the upper chamber through a pipe opening 56. In addition, safety valves 38 and other means necessary for controlling the process are arranged in the upper chamber 15. Connected to the openings 40 at the lower end 28 of the upper chamber are downcomers 42 for conducting water separated from the steam to the lower chamber 16.

The lower chamber 16 is also formed of vertical side walls 44, a lower end 46 and an upper end 48. In the embodiment shown in the figures, the ends are horizontal and completely planar. However, like the ends of the upper chamber, they may be slightly convex if necessary. The water pipes 18 are attached to openings 50 in the upper end 48 of the lower chamber. The lower chamber also has a support plate 52 with openings 54.

The chamber 12 forming the convection part has a large number of vertical unbent water / steam pipes 18. In Fig. 30 only a part of the pipes is shown. The diameter of the pipes is generally smaller than what is shown in the figure. In order to increase the efficiency of heat transfer, the pipes can be fin pipes, in which case ribs 58 are attached to the pipes. For example, the fin pipes are also suitable for use as heat transfer pipes.

As shown in Figure 2, the flue gas duct 20 is passed through a cylindrical boiler so that part of the cylindrical boiler 60 remains outside the flue gas duct. The actual 35 7 87106 convection chamber, in which the water / steam pipes are fitted, remains inside the flue gas duct. The downcomers 42 pass through a portion 60 outside the flue gas duct. The downcomers may also be arranged to pass through the actual convection section 5.

Figure 3 shows a hot water or hot water boiler 62. The ends 26, 28, 46 and 48 of the upper and lower chambers of the boiler are so-called plate ends. The water is introduced into the boiler through a pipe opening into the lower chamber 10 and passes through the water pipes into the upper chamber. from which the heated water is led out of the boiler through a pipe opening.

The invention is not intended to be limited to the embodiments set forth above, but may be modified and applied within the scope of the inventive idea defined by the appended claims.

Claims (15)

A steam or hot water boiler for recovering heat from flue gases or hot process gases in the form of meadow or hot water, comprising a boiler - a convection member (12) arranged in a substantially horizontal straight flue gas duct (20), in which water or duct tubes ( 18) are arranged to run from an upper chamber (14) located above the convection member to a lower kairan (16) located below the convection member, characterized in that - the upper chamber (14) consists of side walls (24), an upper end (26) and a substantially lower lower end (28) and arranged on the horizontal flue gas duct (20), the lower chamber (16) consisting of side walls (44), a lower end (46) and a substantially upper upper end (48) and is arranged beneath the horizontal flue gas duct (20) and, that - the water or meadow tubes (18) are straight throughout their length 20 and attached substantially perpendicularly to both the lower end (28) of the upper chamber and to the lower one chamber upper end (48) and is arranged to run through the flue gas duct perpendicular to the gas flow from the! the upper chamber to the lower chamber thus forming; A convection member (12) in the gas duct. 2. Boiler according to claim 1, characterized in that. the boiler comprises a chamber having the shape of a standing cylinder through which the flue is arranged to run. 30 Boiler according to claim 1, characterized in that. that the upper chamber is in the form of a standing cylinder. 4. Boiler according to claim 1, characterized in that. that the lower chamber has the shape of a standing cylinder. 5. Boiler according to claim 3 or 4, characterized in that. that the ends of the cylindrical chamber are straight or flat. 12 87106 Boiler according to Claim 3 or 4, characterized in that the ends of the cylindrical cannula are plate ends. 5 Boiler according to claim 1, characterized in that the upper chamber and the lower chamber have the shape of an ellipse or a long stretched circle. 8. Boiler according to claim 2, characterized in that in the standing cylinder outside the flue there is arranged one or more drop pipes (42) which are parallel to the meadow or water pipes. 9. Boiler according to Claim 1, characterized in that one or more drop tubes (42) which are parallel to the meadow or water pipes are arranged in the convection part inside the flue duct. 10. Boiler according to claim 1, characterized in that. that fins (58) have been provided in the meadow or water pipes for improving the heat transfer. 11. Boiler according to claim 1, characterized in that. that gun flanges have been provided in the meadow or water pipes for improving the heat transfer. 12. Boiler according to claim 1, characterized in that support plates (32) are provided in the upper and / or the lower chamber for supporting the chambers and controlling the chirping in the chambers. Boiler according to claim 1, characterized in that. that the upper and lower chambers are designed so that the water and / or the meadow move in the same direction in all tubes. 14. The boiler according to claim 1, characterized in that the upper and lower chambers are designed so that the water and / or the meadow move in one direction in single tubes and in the other tubes in the opposite direction. 15. The boiler according to claim 1, characterized in that the upper and lower chambers are made of steel.