RU141859U1 - HEAT EXCHANGE BLOCK - Google Patents

Abstract

1. A heat exchange unit containing in series conjugated at least one high-temperature and at least one low-temperature stage, made with the possibility of independent passage through them of hot gaseous combustion products and heated air, the high-temperature stage includes a set of heat exchange tubes, fixed with the possibility passing through them hot gaseous combustion products and washing outside with heated air, the low-temperature stage includes at least one channel for heated air connected to the high-temperature stage, at least one channel for hot gaseous products of combustion, also connected to the high-temperature stage, and located adjacent to the channel for heated air, and a set of heat pipes, each of which is fixed with the location of the evaporation section in the channel for hot gaseous combustion products with the possibility of being washed from the outside by hot gaseous combustion products and the condensation section - in the channel for heated air with the possibility of washing outside with heated air, the evaporation section and the condensation section of each heat pipe are made straight and oriented relative to each other at an obtuse angle, and each heat pipe is fixed by the evaporation section horizontally with the orientation of the condensation section upwards .2. The block according to claim 1, characterized in that each heat pipe is made with an additional section for fastening, made straight and located in continuation at the free end of the condensation section parallel to the evaporation section. Block according to claim 2,

Description

The invention relates to power engineering, and in particular to a heat transfer unit that can be used to heat atmospheric air before it is fed to burner devices of various energy systems, for example, energy boilers (steam generators), furnaces of oil refineries and metallurgical enterprises.

A recuperative air heater is known, which includes a heat exchange unit, consisting of cubes, structurally formed by welding into the tube boards of steel heat transfer tubes, arranged in a staggered crosswise staggered pattern and forming a staggered bundle (Dobryakov T.S., Migay V.K., Nazarenko BC, Nadyrov II, Fedorov II, Air heaters of boiler plants. Leningrad, "Energy", 1977, p. 8, 9, Fig. 1-1).

Hot gaseous products of combustion (flue gases) pass inside the heat exchange tubes and transfer heat through their walls to the heated air flowing through the space between the tubes and washing their outer surface.

A recuperative air heater is recruited from cubes into steps. As a rule, there are two steps: the first along the heating agent is “hot” and the second (output) is “cold”. This stepped design allows to reduce the temperature of hot gaseous products of combustion and heat the air.

The presence of aggressive components in hot, gaseous products of combustion, both the input and output stages are corroded, due to which the recuperative air heater has an insufficient service life, which determines the shutdown of the unit as a whole (boiler, furnace) to repair or replace corrosion-damaged elements of the heat exchange unit . The output stage, due to the significant temperature difference, as well as the aggressiveness of cold air, often significantly humidified, can undergo more corrosion damage than the input stage.

Known recuperative air heaters of the described design provide a reduction in the temperature of the combustion products to a level acceptable for emission into the atmosphere, but they continue to maintain a sufficiently high temperature, that is, the known recuperative air heaters do not provide complete utilization of the heat of the gaseous products of combustion.

A heat transfer unit is known, which is a device that transfers heat by changing the state of aggregation of a substance inside a sealed pipe partially filled with coolant, which is called a heat pipe, part of which is located in the hot gas duct, and part is cold gas. Such a device contains a stack of heat pipes located vertically in the flues. Water or other known heat transfer agents that change the state of aggregation at the required heating and cooling temperatures can be used as a heat transfer medium (L. L. Vasiliev, Heat exchangers on heat pipes. Minsk, Nauka i Tekhnika, 1981, pp. 9, 10, fig. . one).

A heat exchanger unit with heat pipes efficiently utilizes heat, making it possible to achieve a significantly greater temperature reduction than the recuperative air heater before the gas is released into the atmosphere. The degree of corrosion of the heat pipes is also lower, since there is less temperature difference in the evaporation zone and in the condensation zone of the coolant, which are spaced along the length of the heat pipe.

However, when using, for example, water that evaporates as heat carrier in heat pipes, steam enters the cooling zone (giving off heat to the heated medium), condenses and the condensate returns to the heating zone (in the heat pipe, the medium is under saturation pressure, since the pressure and the temperature is interconnected), heat pipes cannot work in the temperature zone above 330 ° C, since the pressure in them can reach values that require exorbitantly high wall thicknesses, which will lead to unreasonably large metal oemkosti installation and reduce heat transfer efficiency of the heat pipe. Thus, the heat exchange unit only on heat pipes cannot work to recover the heat of hot gaseous products of combustion.

The technical result of this utility model is to expand the arsenal of tools that provide air heating by utilizing the heat of hot gaseous products of combustion, a heat exchange unit that effectively removes the heat of hot gaseous products of combustion to temperatures close to the normal temperature of atmospheric air, and also to increase the service life such a heat exchange unit by increasing corrosion resistance.

The achievement of this technical result is provided by a heat exchange unit, which contains at least one high-temperature and at least one low-temperature stage sequentially coupled, capable of independently passing through them hot gaseous products of combustion and heated air.

The high-temperature stage includes a set of heat-exchange pipes fixed with the possibility of passing through them hot gaseous products of combustion and washing from the outside with heated air.

The low-temperature stage includes at least one channel for heated air connected to the high-temperature stage, at least one channel for hot gaseous products of combustion, also connected to the high-temperature stage and adjacent to the channel for heated air, and a set of heat pipes, each of which is fixed with the location of the evaporation section in the channel for hot gaseous products of combustion with the possibility of washing the outside with hot gaseous products of combustion, and condensation - in the cable for heated air with the possibility of washing from the outside with heated air.

The evaporation section and the condensation section of each heat pipe are straight and oriented relative to each other at an obtuse angle, each heat pipe being fixed by the evaporation section horizontally with the orientation of the condensation section up.

Alternatively, to simplify the manufacture of parts and assembly of the heat exchange unit, each heat pipe is made with an additional section for fixing, made straight and located in parallel to the evaporation section at the free end of the condensation section.

Each heat pipe is made, as a rule, airtight with filling the cavity with at least 10% liquid heat carrier, which can be used water, an aqueous solution of ammonium hydroxide, freon, diphenyl mixture.

The feasibility of the utility model is confirmed by a specific example of the structural implementation of the heat exchange unit, illustrated by the schemes:

- in FIG. 1 is a front view in section;

- in FIG. 2 is a side view in section from the side opposite to the location of the condensation sections of the heat pipes;

- in FIG. 3 is a top view in section of a plane passing through a high temperature stage;

- in FIG. 4 is a fragment of a section of a low-temperature stage in the zone of heat pipe evaporation sites with a plane perpendicular to the heat pipe evaporation sites;

- in FIG. 5 is a fragment of a section of a high temperature stage with a plane perpendicular to the heat exchange tubes;

- in FIG. 6 is a fragment of a section of a low-temperature stage in the zone of heat pipe evaporation sites with a plane parallel to the heat pipe evaporation sites;

- in FIG. 7 is a fragment of a section of a low-temperature stage in the transition zone from evaporation sites to sites: condensation of heat pipes by a plane parallel to the planes of the heat pipes;

- in FIG. 8 - a fragment of a section of a low-temperature stage in the location zone is additional to the sections of the heat pipes by a plane parallel to the planes of the heat pipes.

The arrows indicate the directions of motion of the heated air and hot gaseous products of combustion.

The heat exchange unit contains two high-temperature 1 and one low-temperature 2 stages sequentially coupled, made with the possibility of independent passage through them of hot gaseous products of combustion and heated air through the ducts 3 of the housing 4 (Fig. 1, 2).

The high-temperature stage 1 includes a set of heat exchange tubes 5 mounted vertically with the possibility of passing through them hot gaseous products of combustion and washing from the outside with heated air.

The low-temperature stage 2 includes a channel 6 (Fig. 1) for heated air connected to a high-temperature stage 1, a channel 7 for hot gaseous products of combustion, also connected to a high-temperature stage 1 and located adjacent to the channel 6 for heated air, and a set of heat pipes 8, each of which is fixed with the location of the evaporation section 9 in the channel 7 for hot gaseous products of combustion with the possibility of washing the outside with hot gaseous products of combustion, and the section 10 of condensation in the channel 6 d For heated air with the option of washing the outside with heated air.

The evaporation section 9 and the condensation section 10 of each heat pipe are straight and oriented relative to each other at an obtuse angle.

Each heat pipe 8 is fixed by the evaporation section 9 horizontally with the orientation of the condensation section 10 upward (the horizontal slope upwards is 5-7 degrees, which ensures reliable condensate drainage into the evaporation section 9 from the condensation section 10). The horizontal location of the evaporation section 9 allows to achieve a uniform distribution of heat fluxes along their length. In addition, each heat pipe 8 is made with an additional section 11 (Fig. 1, 8) for fixing, made straight and located on the free end of the condensation section 10 parallel to the evaporation section 9. Due to this design, the heat pipes 8 are easily fixed in the pipe boards 12 (Figs. 1, 4-8) at a right angle, which greatly simplifies the manufacture, since the holes 13 (Fig. 4) in the pipe boards 12 are made round rather than oval.

The parts of the heat exchange unit are made, as a rule, of steel according to known technologies. Also, by known technologies, the connection of parts is carried out. Heat pipes are made airtight with filling the cavities with at least 10% liquid heat carrier selected from the group including water, an aqueous solution of ammonium hydroxide, freon, diphenyl mixture. The degree of filling is determined by calculations depending on the temperature parameters of the heat exchange unit. Typically, the internal volume of the heat pipes 8 is filled with coolant by 20%. The level of coolant in the cavity of the evaporation section 9 is 40% of the inner diameter, which ensures free expansion of the coolant at temperatures below freezing.

In FIG. 8 shows a diagram of the air supply to the furnace 14 and the removal of gaseous combustion products.

The fuel enters through the burner 15 into the furnace 14. Hot gaseous products of combustion from the furnace 14 with a temperature of 350 ° C to 500 ° C pass through the gas duct 16 to the upper high-temperature stage 1 of the heat exchange unit, where they pass through the warm exchange tubes 5, heating them. At the same time, the temperature of the hot gaseous products of combustion decreases to 280-330 ° C.

Next, hot gaseous products of combustion enter the low-temperature stage 2, washing the heat pipes 8 and evaporating the coolant, which is from the cavity section. 9 evaporation moves into the cavity of the condensation section 10. At the same time, the temperature of the hot gaseous products of combustion decreases even more and reaches a temperature of 30-40 ° C at the stage of passage through the exhaust fan 17. The smoke exhaust 17 evacuates the gaseous products of combustion into the atmosphere through the chimney 18.

Heated air is pumped into the heat exchanger unit by a blower fan 19, which washes the condensation sections 10 of the heat pipes 8, cooling them and heating, then enters the high-temperature stage 1, washing the heat exchangers 5, where its temperature reaches 260-430 ° C. From the high-temperature stage 1, heated air is supplied to the burner devices 15, ensuring efficient combustion of fuel in the furnace 14.

Claims (3)

1. A heat exchange unit comprising at least one high temperature and at least one low temperature stage sequentially coupled, capable of independently passing through them hot gaseous products of combustion and heated air, the high temperature stage includes a set of heat exchange tubes fixed with the possibility passing through them hot gaseous products of combustion and washing from the outside with heated air, the low-temperature stage includes at least one a channel for heated air connected to a high-temperature stage, at least one channel for hot gaseous products of combustion, also connected to a high-temperature stage and adjacent to a channel for heated air, and a set of heat pipes, each of which is fixed with the location of the evaporation section in the channel for hot gaseous products of combustion with the possibility of washing from the outside with hot gaseous products of combustion, and the condensation section in the channel for heated air with By washing the outside with heated air, the evaporation section and the condensation section of each heat pipe are straight and oriented relative to each other at an obtuse angle, and each heat pipe is fixed by the evaporation section horizontally with the orientation of the condensation section up. 2. The block according to claim 1, characterized in that each heat pipe is made with an additional section for fixing, made straight and located in continuation on the free end of the condensation section parallel to the evaporation section. 3. The block according to claim 2, characterized in that each heat pipe is made airtight with filling the cavity with at least 10% liquid heat carrier selected from the group comprising water, an aqueous solution of ammonium hydroxide, freon, diphenyl mixture.

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