RU2418246C1 - Hot-water boiler - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: boiler includes radiant burner for combustion of gaseous or liquid fuel, and vertical cylindrical housing with distributing chamber of hot flue gases, collecting chamber of cooled flue gases and inlet and outlet branch pipes of working media. Along vertical axis of housing there in-series arranged in flue gas direction is water heater and air heater, each of which consists of two or more heat exchange units, as well as peripheral and central headers. Heat exchange unit is assembled around vertical axis of housing in the from of annular row of heat transfer elements with radial spiral slot channels for movement of heated media (water and air) and vertical slot channels of spiral-shaped section for movement of heating medium - flue gas. Between adjacent heat exchange units of each of heaters in peripheral and central headers there installed in turn are horizontal partitions which guide water and air flows subsequently from one heat exchange unit to the next unit.

EFFECT: reduction of metal consumption and overall dimensions of boiler, and decrease of fuel consumption.

3 cl, 4 dwg

Description

The invention relates to a device for heating water and can be used to provide hot water heating systems and hot water supply to industrial, residential and public facilities.

A well-known boiler type KVG, containing a burner, a cylindrical body with nozzles for supplying and discharging heated water, as well as a furnace and convective heating surfaces placed inside the boiler body, which are made of vertical pipes fixed by the ends in the bypass ring collectors (Boilers and boiler plants for industrial and municipal energy. The industry catalog. - M.: Publishing house TsNIITEIityazhmash, 1998, p. 38-39).

The disadvantages of this boiler are:

- a significant volume of the furnace, which results in large dimensions and metal consumption of the boiler;

- the low speed of the water circulating in the heat exchange pipes, leading to intensive scale deposition, accompanied by overheating and destruction of the pipes and, as a result, to the low reliability of the boiler and high maintenance costs for its repair;

- high temperature of the exhaust gases, which leads to significant heat loss and, consequently, increased fuel consumption;

- burning fuel at a high temperature (approximately 2000 ° C), as a result of which a large amount of harmful substances (СО, NO _x ) are released into the environment.

A well-known hot water boiler containing a burner, a horizontal cylindrical body with nozzles for supplying and discharging heated water, a firebox and a convective heating surface placed inside the boiler body, made of horizontal straight pipes fixed at their ends in two vertical bypass ring collectors, one of which is equipped with a in the lower part a water supply pipe, and the second - a heated water discharge pipe located in the upper part, thanks to the installed inlet multi-way horizontal-lifting movement of water is provided to the quick collectors in a checkerboard pattern for partitions (patent RU No. 2146790, Cl. F24H 1/00, publ. 03.20.2000, bull. No. 8).

The main disadvantages of this invention include:

- a significant volume of the furnace, leading to large dimensions and metal consumption of the boiler;

- the inability to ensure uniform washing of the heat exchanger pipes with combustion products and the transverse-direct-flow diagram of the flows of heat transfer media that do not provide a sufficiently high value of the average heat transfer coefficient, resulting in increased dimensions and mass of the heat transfer surface of the boiler;

- burning fuel at a high temperature (approximately 2000 ° C), as a result of which a large amount of harmful substances (СО, NO _x ) are released into the environment.

Known hot water boiler containing installed in the housing front, ceiling, rear and side screens, which are made of gas-tight fin pipes and connected to the respective horizontal collectors. Screens have partial openings for the passage of flue gases (USSR copyright certificate No. 1719806, Cl. F24H 1/32. 1989).

The disadvantage of this boiler is its low efficiency, since when moving inside the boiler, the flue gases do not have enough time to give off enough heat and leave the boiler with a high temperature, resulting in large heat losses, and in addition, a large amount of flue gases is emitted into the environment harmful impurities (СО, NO _x ).

Also known is a hot water boiler containing frontal, rear, ceiling and side screens located in the housing, made of gas-tight fin pipes and connected to the respective horizontal collectors. Each side screen consists of three separate panels - the outer and two inner. The boiler is also equipped with an internal horizontal gas tight screen dividing the furnace space into radiation and convection parts. Due to the absence of fins in certain sections of the inner panels, the presence of openings, partitions and an additional gas duct formed between the ceiling and the inner screen, the path of the flue gases in the volume of the boiler is increased, which ensures a higher heat transfer rate and lower temperature of the flue gases at the outlet of the boiler (patent RU No. 2210702, CL F24H 1/00, publ. 08/20/2003, bull. No. 23).

The disadvantages of the boiler are as follows:

- high metal consumption of the boiler due to the large number of screens, each of which contains two collectors;

- increased hydraulic resistance of the flue gas flow due to the large number of turns in the gas path;

- fuel combustion is carried out at a high temperature, which leads to the discharge of a large amount of harmful impurities (СО, NO _x ) with flue gases into the environment.

The objective of the invention is to increase the efficiency and decrease the metal consumption of the boiler due to the intensification of heat transfer and deep heat recovery of the exhaust flue gases.

The objective of the invention is the elimination or minimization of emissions of harmful substances into the environment with exhaust flue gases.

To solve the tasks, a hot-water boiler was developed, which contains a burner for burning gaseous or liquid fuels and a vertical cylindrical body with a distribution chamber of hot flue gases coming from the burner, a pre-assembled chamber of cooled flue gases, and nozzles for supplying and discharging working fluids;

along the vertical axis of the casing, a water heater and an air heater with an intermediate chamber between them are arranged sequentially along the flue gas stream;

a water heater and an air heater contain two or more heat exchange units mounted one above the other with the formation of peripheral and central collectors, separated from adjacent cavities by sealed plugs;

each heat transfer unit is formed of vertically mounted, adjacent to each other heat transfer elements welded together by vertical seams and forming an annular row around the vertical axis of the housing, each heat transfer element is made hollow of two walls with spacing protrusions having a cross-section in the form of a spiral welded between each other on two horizontal sides and forming in the inner cavity a radial-spiral slotted channel that communicates with the peripheral and central th collectors respectively to move heated water and heated air, and between adjacent to each other by the heat transfer elements formed by vertical slotted channels spiral section communicated with the junction, and the intermediate collecting chamber and adapted to move in the axial direction of the flue gases cooled;

between the adjacent heat exchange blocks of each of the heaters, horizontal partitions are installed alternately in the peripheral and central collectors, separating the collectors into separate isolated cavities and directing the flows of water and air, respectively, after the heat transfer elements of one unit have expired from the internal cavities into the internal cavities of the subsequent unit heat transfer elements.

In addition, the proposed hot water boiler provides for the selection of part of the cooled flue gases from the total flow to mix with the air supplied to the burner, as well as the use of a flameless type burner.

Below the essence of the invention is illustrated by a specific example of its implementation and the accompanying drawings, in which:

figure 1 depicts a General view of the boiler, a longitudinal section;

figure 2 - section aa in figure 1;

figure 3 - fragment B in figure 2;

figure 4 - section bb in figure 3,

The boiler contains a flameless burner 1, a vertical cylindrical casing 2 with a hot flue gas distribution chamber 3, a chilled flue gas collection chamber 4, pipes 5 and 6, respectively, for supplying and discharging heated water and pipes 7 and 8 for supplying and discharging heated air, respectively. Along the vertical axis of the housing 2, a water heater 9 and an air heater 10 with an intermediate chamber 11 between them are arranged sequentially along the flue gas stream. In this example, the water heater 9 consists of four heat exchange units 12, and the air heater 10 consists of two heat exchange units 13. The heat exchange units 12, as well as the heat exchange units 13 are mounted one above the other to form the peripheral 14 and central 15 collectors of the water heater 9 and the peripheral 16, and central collector 17 of the heater 10. The peripheral manifolds 14 and 16 are separated from adjacent cavities by sealed plugs 18, and the central collectors 15 and 17 are sealed by plugs 19. Heat-exchange blocks 12 and 13 are formed Ans are made of vertically mounted, adjacent to each other and forming an annular row of heat transfer elements 20, each of which is made hollow of two walls 21, which have a cross-section in the form of a spiral, are equipped with spacing protrusions, are welded together on two horizontal sides and form in the inner cavities radial-spiral channels 22, communicating with peripheral 14 and 16 and the central 15 and 17 collectors. Between adjacent heat transfer elements 20 are formed vertical slotted channels 23 of a spiral cross section, communicated with the distribution 3, team 4 and the intermediate 11 chambers. Between adjacent heat exchange blocks 12 of a water heater 9, and also between adjacent heat exchange blocks 13 of a water heater 10, horizontal partitions 24 and 25 are installed in the peripheral collectors 14 and 16 and in the central collectors 15 and 17, separating the collectors into separate isolated cavities. A fan 26 is installed on the air supply line to the air heater, and a smoke exhaust 27 is installed at the outlet of the cooled flue gases from the collection chamber 4. A line 28 is provided for mixing part of the cooled flue gases to the cold air, and for supplying a heated mixture of air and flue gases to the burner 1 - line 29.

In this example, the installation of burner 1 is provided in the lower part of the boiler, and the placement of the air heater 10 is above the water heater 9. However, in principle, it is possible to design the boiler with the installation of burner 1 in the upper part of the boiler; in this case, the air heater 10 is installed under the water heater 9.

The hot water boiler operates as follows. Hot flue gases, after burning fuel in a flameless burner 1, enter the distribution chamber 3, then, rising up successively through the vertical slotted channels 23 of the heater 9, the intermediate chamber 11 and the vertical slotted channels 23 of the heater 10, are gradually cooled, giving off heat to water and air , and then enter the collection chamber 4, from where they are pumped out by a smoke exhaust fan 27. Cold water is supplied from the system through the pipe 5 to the upper cavity of the peripheral collector 24 separated by a partition 24, water heating Atelier 9, passes through the radial-spiral channels 22 of the upper heat exchange unit 12, enters the upper cavity of the central collector 15, separated by a partition 25, then similarly pumps sequentially through the radial-spiral channels 22 of three downstream heat-exchange blocks 12; in this case, the water, taking heat from the flue gases, is heated, after which the hot water is discharged through the pipe 6 into the system. A part of the cooled flue gases along the line 28 is mixed with the cold air supplied to the boiler, then the resulting mixture of air and flue gases is fed by the fan 26 through the pipe 7 into the upper cavity of the peripheral channel 16 of the air heater 10, is pumped sequentially through the radial-spiral channels 22 of two heat exchange units 13, heats up in them, taking away heat from flue gases, after which it is removed through the pipe 8 and fed through line 29 to the burner 1.

The significant advantages of the proposed hot water boiler are as follows:

1. Due to the implementation of the heat exchange surfaces of water and air heaters in the form of slotted channels and countercurrent heating (flue gases) and heated (water and air) heat transfer media, high efficiency of the heat transfer process and the possibility of deep heat recovery of flue gases are ensured, which, in turn, allows to achieve a significant reduction in the metal consumption and dimensions of the boiler, as well as reducing fuel consumption.

2. Dilution of air with chilled flue gases reduces the adiabatic combustion temperature to 1000-1200 ° C, at which the formation and emission of harmful impurities (CO and NO _x ) into the environment with flue gases is virtually eliminated.

3. Thanks to the use of a flameless type burner, a stable combustion process is ensured, despite the low oxygen content in the air entering the burner due to the mixing of recirculated flue gases to it.

Claims (3)

1. A water boiler containing a burner for burning gaseous or liquid fuel and a vertical cylindrical body with a distribution chamber of hot flue gases coming from the burner, a chilled flue gas collection chamber and nozzles for supplying and discharging working fluids, moreover, along the vertical axis of the casing are arranged sequentially along the flue stream gas water heater and an air heater with an intermediate chamber between them, each of which consists of two or more heat exchange units installed one above the other In order to form peripheral and central collectors separated from adjacent cavities by hermetic plugs, each heat exchange unit is formed of vertically mounted, adjacent to each other heat transfer elements welded together by vertical seams and forming an annular row around the vertical axis of the housing, each heat transfer element is made hollow of two walls with spacing protrusions having a spiral shape in cross section, welded together on two horizontal sides and a radial-spiral slotted channel in the inner cavity that communicates with the peripheral and central collectors to move respectively heated water and heated air, vertical slotted channels of spiral cross section are connected between adjacent heat transfer elements, connected to the distribution, intermediate and prefabricated chambers and designed to axial movements of cooled flue gases, and between adjacent heat exchange units of each of the heaters alternately, horizontal partitions are installed in the peripheral and central collectors, dividing the collectors into separate isolated cavities and directing water and air flows, respectively, after the heat-transfer elements of one heat-transfer unit flow from the internal cavities to the internal cavities of the heat-transfer elements of the subsequent heat-exchange unit. 2. The boiler according to claim 1, characterized in that part of the flue gas cooled therein is taken from the general stream and mixed with air intended for supply to the burner. 3. The boiler according to claim 1, characterized in that it uses a flameless type burner.

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