RU2265770C2 - Water-gas-tubular boiler - Google Patents

Abstract

FIELD: heat power engineering.

SUBSTANCE: water-gas-tubular boiler has outer heat exchanging surface defined by the ring set of vertical pipes spaced at a distance equal to their outer diameter. The pipe set is mounted in the space on the outer surface of the furnace, and its ring periphery is at a distance from the inner cylindrical shell of the steam-water drum equal to two or three outer diameters of the pipes of the ring set. The pipe set comprises two ring bank of alternating pipes. The distance between pipes in the first bank is twice outer diameter of the pipes, and the pipes are in communication with the steam-water drum. The pipes of the second pipe bank are connected with the water and steam-water collectors which are in communication with the steam-water drum through water and steam-water branch pipes. The gas duct with vertical and horizontal baffles that define several sections of the gas duct is interposed between the ring set of pipes and inner cylindrical shell of the steam-water drum. The bottom section of the gas duct is in communication with the bottom section of the furnace, and the top section is in communication with the fire tube. The furnace device is positioned at the top of the boiler, and the outer diameter of the ring water and steam-water collectors does not exceed the diameter of the furnace.

EFFECT: improved structure and enhanced efficiency.

1 cl, 2 dwg

Description

The invention relates to the field of power engineering, and specifically to boiler building, and can be used in steam boilers for stationary and transport energy.

Known steam water tube boiler of the Finnish company "Rauma-Repola" type UNEX NA, containing fastened to each other steam and water drums of a mountain shape with a flat upper bottom and a tube board through two rows of vertical evaporation pipes. The furnace device is located along the axis of the boiler above the steam-water drum, and the furnace space in the form of a furnace is provided on the outside with a radiation heat exchange surface in the form of the first and second rows of pipes, which together form a tube bundle. Gases from the furnace pass through a bundle of pipes and are discharged into a gas outlet pipe (see the book by Enin V.I. et al. Ship boiler installations. M: Transport, 1993. p. 107, 109-110). The disadvantages of the known steam tube boiler are:

- low efficiency of convective heat transfer and, as a result, low boiler efficiency due to the small number of pipes in the gas duct (two rows) and low gas flow rate in the annular space of the gas duct due to the high height and free (in the light) cross-sectional area of the gas duct in the outer space of the furnace;

- the difficulty of cleaning the annular space of the gas duct due to its inaccessibility for inspection or mechanical cleaning.

These disadvantages limit the use of known steam boilers in ship and stationary conditions.

Known steam water-gas boiler containing a steam and water drum formed by the upper and lower generators in a flat design as well as vertical inner and outer cylindrical shells, a water collector, elements of the duct and gas duct with a consecutive arrangement of the air supply pipe, furnace device, firebox with external water-tube evaporative heat exchange surface formed by an annular vertical row of evaporation tubes placed around the furnace, smoke weaving and gas chamber (see A.S. SU 8945, F 22 B 21/06, 04/30/1929). This boiler, as the closest, is selected as a prototype of the proposed solution for most of the features.

The disadvantages of the known steam boiler are:

- insufficient heat transfer efficiency of the water-pipe part of the heat exchange surface, since evaporative pipes only take up half their surface heat, facing the internal volume of the furnace space;

- use as a heat exchange element of the smoke tube, characterized by low heat transfer efficiency;

- low efficiency of water circulation and the steam-water mixture, including in the area of the smoke tube of the steam-water drum and, as a result, the formation of deposits in it, deposits with the subsequent development of fatigue cracks during operation.

Thus, the steam boiler prototype has significant design flaws that reduce the technical and economic performance of the boiler.

The task to be solved by the claimed invention is directed is the elimination of the indicated technical, economic and structural disadvantages, namely:

- ensuring efficient heat transfer in the water and gas pipe parts of the boiler with the exception of the development of fatigue cracks in operation;

- improving the efficiency of heat transfer by attracting the use of an additional heat transfer surface;

- ensuring reliable circulation of water and steam-water mixture in the steam-water drum.

The problem is achieved in that in a known steam boiler containing a steam-water drum formed by the upper and lower generators in a flat design, as well as vertical inner and outer cylindrical shells, a water collector, elements of the duct and duct with the consecutive arrangement of the supply pipe air, a combustion device, a furnace with an external water-tube evaporative heat exchange surface formed by an annular vertical row of evaporation pipes located DC furnace, a flue gas outlet chamber and, in contrast to the claimed additional steam has an annular manifold disposed above the combustion chamber in the space inside the sleeve steam drum. The outer water tube evaporative heat exchange surface, placed around the furnace, is formed by an annular vertical row of pipes with a step equal to their outer diameter, placed in space on the external surface of the furnace with the ring circumference of the row from the inner cylindrical shell of the steam-water drum by an amount equal to two to three outer diameters pipes of the annular row. In this case, the annular row of pipes contains two annular bundles of alternating pipes, the first of which is made with a step along the perimeter equal to the double outer diameter of these pipes, and communicated along each tube of the bundle at its upper and lower ends with the cavity of the steam-water drum, and the second bundle also performed with a step along the perimeter equal to the double outer diameter of the pipes, similarly communicated along each of its pipes in its lower and upper ends with annular respectively water and steam-water collectors in communication with steam-water arabanom respectively by water and steam pipes. Between the annular row of pipes and the inner cylindrical shell of the steam-water drum there is a gas duct with vertical and horizontal partitions with the formation of several consecutive sections of the gas duct with a spiral-annular upward movement of the gas flow, communicated in the lower part with the lower part of the furnace and in the upper part with a smoke pipe bonded with the inner and outer cylindrical shells of the steam-water drum and the gas chamber. In this case, the furnace device is located in the upper part of the boiler and is aligned with its axis, and the outer diameter of the ring water and steam-water collectors does not exceed the diameter of the furnace. It is advisable that the ductwork in which the duct further comprises a heat-retaining air heater located in the space between the outer shell of the steam-water drum and the outer shell of the boiler, provided with vertical and horizontal partitions with the formation of several consecutive sections of the duct with a spiral-circular movement of the air flow and connected at the inlet with the nozzle air supply, and at the exit with a combustion device.

The claimed combination of restrictive and distinctive features improves the technical, economic, operational and structural characteristics of the boiler.

The placement in the space on the outer surface of the furnace of the annular row of pipes at a distance of two to three outer diameters of the pipes from the inner cylindrical shell of the steam-water drum allows, firstly, to form a gas duct in the gap between the outer surface of the furnace and the inner cylindrical shell of the steam-water drum, and secondly, to use for convective heat transfer, which increases its efficiency, the outer surface of the annular row of evaporation pipes and the surface of the inner cylindrical shell of the steam Nogo drum.

Placement of vertical and horizontal partitions in the specified flue with the formation of several consecutive sections of the flue with a spiral-circular movement of the gas stream allows optimizing the gas flow rate and obtaining high heat exchange efficiency between gases and the wall surface with an increase in the length of the gas duct and the contact time between the heat-exchanging media. Moreover, these partitions provide an increase in the strength of the cylindrical part of the inner shell of the steam-water drum. The connection of the aforementioned gas duct with the volume of the furnace space in the lower part and with the chimney in its upper part makes it possible to create an upward movement of the gas flow and reduce the aerodynamic resistance of the gas duct.

Placing two bundles of pipes in an annular row of pipes around the furnace, one of which is made with a step along the perimeter equal to the double outer diameter of the pipes and communicated in the upper and lower ends with a steam-water drum, and the other, also made with a step along the perimeter equal to the double outer the diameter of the pipes communicated at the lower and upper ends with annular respectively water and steam-water collectors with an external diameter slightly smaller than the inner diameter of the furnace, allows access to the internal space of the gas duct for its inspection and cleaning during operation by displacing the second beam relative to the first in the axial direction of the furnace after disconnecting from the water and steam-water pipes by using collapsible connections communicated with the steam-water drum.

Placing in the duct in the space between the outer shell of the steam-water drum and the outer shell of the boiler an additional heat-retaining air heater, equipped with vertical and horizontal partitions with the formation of several consecutive sections of the duct with a spiral-circular movement of the air flow and connected at the inlet to the air supply pipe, and at the outlet to the furnace device, allows for such a design of the duct, firstly, to reduce the loss of heat into the surrounding space to breaking off and thereby increase the boiler efficiency, secondly, reduce the consumption of insulating materials on the outer surface of the boiler shell, thirdly, increase the temperature of gases in the volume of the furnace space by supplying heated air to the furnace with an increase in the efficiency of radiation heat exchange in the furnace, fourthly, eliminate the possibility of sulfuric acid corrosion when installing an additional gas air heater in the boiler; fifthly, improve the circulation of water and the steam-water mixture in the steam-water drum due to some cooling the outer shell of the steam-water drum with the creation of a downward movement of water without steam bubbles in the wall layer of the outer shell of the drum.

Thus, an improvement is achieved in the structural, technical, economic, and operational characteristics of the boiler when a number of additional effects appear.

The claimed technical solution is illustrated by the following illustrations. Figure 1 presents a diagram of a longitudinal section of the boiler, and figure 2 is a diagram of a cross section (section AA according to the view in figure 1) of a steam boiler.

The steam boiler has the following device. The steam boiler contains (Fig. 1) a steam-water drum 1 with a space formed by the inner 2 and outer 3 cylindrical shells paired with flat upper 4 and lower 5 bottoms. A furnace 6 is located along the axis of the steam-water drum, the outer side surface of which is formed by an annular row of pipes 7 installed in increments equal to the outer diameter of the pipes. This annular row of pipes is formed by two annular bundles of alternating pipes 8 and 9 with steps along the circumference of each equal to the double outer diameter of the pipes. In this case, the upper and lower ends of the tube bundle 8 are communicated through the inner shell 2 with the cavity of the steam-water drum, and the upper and lower ends of the tube bundle 9 are in communication with the cavities of the annular steam-water 10 and water 11 collectors. The collectors 10 and 11 are communicated through steam-water 12 and water 13 pipes through the inner shell 2 with the cavity of the steam-water drum. The outer diameter of the annular collectors 10 and 11 is slightly smaller than the diameter of the furnace and the inner diameter of the annular row of pipes 7. The circumference of the annular row of pipes 7 is spaced from the inner cylindrical shell 2 by an amount equal to 2-3 outer diameters of the pipes 7, which corresponds to the ratio that the diameter of the annular row pipes 7 is less than the diameter of the inner shell 2 by four to six external diameters of the pipes 7. The space between the annular row of pipes 7 and the inner shell 2 forms a gas duct 14 containing vertical 15 and horizontal 16 partitions, to torye flue 14 is divided into successive portions flues with ascending spiral motion of the annular gas flow. The gas outlet from the furnace 6 is communicated with the inlet of the gas duct 14 in the lower part of the furnace between the pipes 8 and 9, and the gas outlet from the gas duct 14 is communicated with a smoke pipe 17 fixed to the drum shells 2 and 3 and a gas outlet chamber (not shown).

At some distance from the outer shell 3 of the steam-water drum, there is an outer cylindrical shell of the boiler 18 with an air supply pipe 19 installed on it. The space between the shells 3 and 18 forms a heat-saving air heater in the form of an air duct 20, equipped with vertical 21 and horizontal 22 partitions. Partitions 21 and 22 together form an air duct with an upward spiral-circular movement of the air flow, which at the outlet is connected to the furnace device 23 of the boiler. The furnace device 23 is located in the upper part of the boiler and is aligned with the axis of the furnace 6.

Under the furnace 6 at the bottom, it is provided with thermal insulation 24 from a heat-resistant material (brick), combined with the level of the water collector 11.

Water-gas boiler is used as follows. Air from the boiler fan (not shown) is supplied to the air supply pipe 19. Next, the air passes through a heat-retaining air heater in the form of an air duct 20 and after some heating from contact with the outer shell 3 of the steam-water drum enters the furnace device 23, as shown by the bright arrows in FIG. 1 and 2. Fuel furnace is also supplied to the combustion device 23 from a fuel pump (not shown). The fuel-air mixture formed in the device 23 enters the furnace 6 and burns in the form of a torch with the release of heat. The radiation part of the torch heat is perceived by the inner heat exchange surface of the annular inflow row of pipes 7. In the region of the lower sections of the evaporation tubes of bundles 8 and 9, the combustion products from the lower part of the furnace 6 between pipes 8 and 9 enter the lower part of the duct 14, equipped with horizontal 22 and vertical 21 partitions with the formation of several consecutive sections of the duct 14 with a spiral-circular movement of the gas stream, as shown by the bright arrows in figures 1 and 2. Due to convective heat transfer of temperatures and the gases at the outlet of the duct 14 are reduced, and the heat is transferred to the outer surface of the evaporation tubes 7 and the inner surface of the shell 2 of the steam-water drum 1. Next, the gases from the upper section of the duct 14 enter the smoke pipe 17. Here the final heat is removed from the gases to the walls of the smoke pipe 17, performing the function of an evaporation pipe. Cooled gases from the boiler are discharged through a gas chamber to a chimney or gas air heater (not shown).

Feed water is supplied to the steam-water drum 1. When heat is supplied from the gases to the evaporation pipes 7 and the inner surface of the shell 2, steam is formed, which in the form of a steam-water flow moves up and down inside the pipes 7 and in the wall layer of the shell 2, as shown by light-dark arrows in figure 1. In the near-wall layer of the shell 3, due to its cooling by air from the side of the heat-preserving air heater 20, a stable lowering movement of water is provided, as shown by the dark arrows in Fig. 1. This ensures the circulation of water and steam-water mixture in the boiler.

Cleaning the inner space of the duct 14 from deposits is as follows. Dismantle the combustion device 23 and fix the position of the annular collector 10 by means of a lifting device (not shown). Then, the fasteners are removed from the flanges of the nozzles 12 and 13 and the tube bundle 9 with collectors 10 and 11 is lowered into the lower space under the steam-water drum 1. The pipe part and the outer surface of the shell 2 are cleaned of deposits through the gaps between the tubes of the bundles 8 and 9. Then, lifting and installing a bundle of pipes 9 with collectors 10 and 11 in a regular place with the installation of fasteners, remove the lifting device and install the combustion device in a regular place. After the pressure test, the boiler can be put into operation.

This operation to clean the duct 14 is associated with the need for free space under the lower level of the steam-water drum 1 with a height not less than the height of the tube bundle 9. The specified operation to dismantle the tube bundle 9 with collectors 10 and 11 provides the convenience of the necessary repair or replacement of the heat exchange surface during operation .

Claims (2)

1. A gas-and-gas boiler containing a steam and water drum formed by the upper and lower generators in a flat design, as well as vertical inner and outer cylindrical shells, a water collector, elements of the duct and gas duct with a sequential arrangement of the air supply pipe, furnace device, and furnace with an external water-tube evaporative heat exchange surface formed by an annular vertical row of evaporation pipes located around the furnace, smoke tube and gas outlet of the second chamber, characterized in that it further comprises an annular steam-water collector located above the firebox in the space of the inner shell of the steam-water drum, the outer water-tube evaporative heat exchange surface, placed around the firebox, is formed by an annular vertical row of pipes with a step equal to their outer diameter placed in space on the outer surface of the furnace with the distance of the circumference of the ring of the row from the inner cylindrical shell of the steam-water drum by an amount equal to two or three outer dia meters of pipes of an annular row, and containing two annular bundles of alternating tubes, the first of which is made with a step along the perimeter equal to the double outer diameter of these pipes, and communicated along each tube of the bundle in its upper and lower ends with the cavity of the steam-water drum, and the second the beam, also made with a step along the perimeter equal to the double outer diameter of the pipes, is likewise communicated along each of its pipes in its lower and upper ends with annular respectively water and steam-water collectors communicated with the steam nym drum respectively by the water and steam pipes; between the annular row of pipes and the inner cylindrical shell of the steam-water drum there is a gas duct with vertical and horizontal partitions with the formation of several consecutive sections of the gas duct with a spiral-circular upward movement of the gas stream, communicated in the lower part with the lower part of the furnace, and in the upper part with a smoke pipe, bonded to the inner and outer cylindrical shells of the steam-water drum and the gas chamber, and the combustion device is located in the upper part of the boiler and aligned with its axis, and the outer diameter of the annular water and steam-water collectors does not exceed the diameter of the furnace. 2. The gas and gas boiler according to claim 1, characterized in that the duct further comprises a heat-retaining air heater located in the space between the outer shell of the steam-water drum and the outer shell of the boiler, provided with vertical and horizontal partitions with the formation of several consecutive sections of the duct with a spiral-circular movement of the air flow and connected at the inlet to the air supply pipe, and at the outlet to the combustion device.

Images