RU2533591C1 - Liquid heating method and liquid heater on its basis - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: invention involves liquid heating in a contact heat exchanger by heating gaseous medium, further separation of the heated liquid from the heating gaseous medium, compression of the separated heated liquid to the pressure exceeding the saturation pressure, at the required end temperature of liquid heating, by a value of margin for non-boiling and hydraulic losses, and final liquid heating, after its compression, with the heating gaseous medium, after separation from it of the heated liquid, through a separating solid heat exchange wall with further discharge of the heated liquid to the user.

EFFECT: providing increase of liquid heating temperature without any compression of gaseous medium at use of contact heat exchange between the heating and heated media in a high-temperature zone of gaseous medium.

5 cl, 1 dwg

Description

Technical field

The group of inventions relates to the field of power engineering, and in particular to methods and installations for heating a liquid, mainly water, for technological or domestic heating, and can find application in various fields of the national economy.

State of the art

There is a method of heating a liquid, which consists in heating an intermediate liquid coolant by sparging its layer with the combustion products obtained as a result of burning fuel with the formation of a water-gas-gas stream, transferring heat of the latter through the wall of a heated liquid, separating water from the water-gas-gas stream by separation, followed by its return to the layer and transferring it heat when returning through the wall of the heated fluid, while the gas-vapor flow before throttling is throttled, and the excess pressure e above the layer of the intermediate coolant support in the range of 0.02-0.005 MPa (see RF patent for the invention No. 2091673, F24H 1/10, publ. 09/27/1997).

A disadvantage of the known method of heating a liquid in a gas-liquid heat exchanger is the impossibility of heating an intermediate liquid coolant above the saturation temperature of this coolant, corresponding to the pressure of the fuel combustion products. Increasing the pressure of the combustion products to increase the temperature of the heated fluid in this method necessitates a significant expenditure of energy on the compression of the gaseous oxidizer and gaseous fuel (if used), which dramatically reduces the energy efficiency of heating the liquid.

The closest in technical essence to the proposed invention is a known method of contact heating of a liquid with gaseous products of fuel combustion with countercurrent flow of heating and heated streams in a heating stage (see the book Sosnin Yu.P. Contact water heaters. - M .: Stroyizdat, 1974, p. 134-135, Fig. 60).

In the known method of contact heating a liquid, a heated liquid is supplied to the contact chamber while simultaneously supplying gaseous products of fuel combustion into the chamber from the combustion chamber. Before the heated fluid is supplied to the contact chamber, the liquid is partially heated by the products of fuel combustion leaving the contact chamber.

A disadvantage of the known method of contact heating of a liquid with fuel combustion products is the inability to heat the liquid above the saturation temperature of this coolant, corresponding to the pressure of the fuel combustion products. Increasing the pressure of the combustion products to increase the temperature of the heated liquid in this method requires a significant expenditure of energy on the compression of the gaseous oxidizer and gaseous fuel (if used), which dramatically reduces the energy efficiency of heating the liquid. In turn, the impossibility of economically increasing the temperature of the heating fluid in the known method limits the scope of the possible use of cheap contact heating of the fluid with high-temperature gases.

Also known is a liquid heater having a hollow body and a flow-through shell-and-tube heat exchanger connected to the body, the cavity of which serves as a furnace and which is equipped with a nozzle for outputting the heated liquid to the consumption of at least one burner and a contact heat exchanger with a nozzle and a droplet separator, between which a distributor for irrigation nozzles supplied with heating fluid, while the housing is made in the form of an intermediate tank equipped with an overflow nozzle in the middle for a heated fluid bones, on the cover of which the shell-and-tube and contact heat exchangers are rigidly fixed, while the burner is installed above the firebox on the end cover of the shell-and-tube heat exchanger, which is connected through the circulation pump to the intermediate tank below the level of the overflow pipe, and the cavity of the furnace and contact heat exchanger communicate through the corresponding openings made in housing cover for the counter passage of combustion products and heated fluid above the level of the overflow pipe (see RF patent for utility model No. 9051, F24H 1/00, publ. January 16, 1999).

The disadvantages of this liquid heater are the high metal consumption and the cost of the water heating system using a shell-and-tube heat exchanger due to the need to use an expensive high-temperature (screen) heating surface in it, as well as high operating costs due to the corrosion wear of the shell-and-tube heat exchanger during operation in the high temperature zone of products combustion, or because of water treatment to prevent corrosion, which reduces the efficiency of heating the liquid.

A heat generator is known comprising a supercharger, the pressure and suction nozzles of which are connected by a technical fluid circulation pipe equipped with a consumable nozzle, an inkjet apparatus located in the pipeline and including a fluid supply nozzle connected to the pressure nozzle, a nozzle, a receiving chamber with a gas nozzle and a mixing chamber, a heat exchanger heated product with a product heater, including a housing with a product supply pipe and placed on the mixing chamber, a settler of a gas-liquid mixture a liquid removal pipe connected to a suction pipe, located in the pipeline and including a technical liquid filter, a drain pipe, a liquid feed pipe and a gas chamber, and also containing a furnace including a combustion chamber and a burner with a gas exhaust pipe connected to the gas pipe, a liquid superheater , a steam generator and a superheater with a nozzle for issuing superheated steam, while the heat exchanger housing is vertically placed, provided with thermal insulation, a heat compensator, for example, a lens, and its bottoms are made with holes in the form of upper and lower flanges, the lower flange is fastened, for example, by bolts with nuts with a sump by means of an additionally installed flange pipe on it, the mixing chamber is made in the form of several pipes fixed in the said holes of the flange bottoms of the body, the aforementioned superheater liquid product, a steam generator and a superheater with a superheated steam outlet are placed in the heat exchanger housing, a tank with a technical fluid inlet includes flange days e apertured flange secured to the upper bottom of the hull, for example, studs and nuts, with the formation of said receiving chamber with the gas jet apparatus nozzle, and the nozzle jet apparatus mounted coaxially mixing chambers in the holes of the bottoms tank, e.g., on the thread (see. RF patent for the invention No. 2137052, F24H 3/02, publ. September 10, 1999).

The disadvantages of the known heat generator are the high metal consumption and cost due to the use of an expensive steam generator heating surface, as well as low energy efficiency due to the use of a steam injector to increase the pressure of the mains water, the efficiency of which in pump operation is only a few percent and leads to excessive fuel consumption.

A known liquid heater (a system for utilizing heat of combustion products) comprising a gas duct connected respectively to a heat generator and a chimney with a contact heat exchanger and a condenser with a heated path connected in series along the gases and communicated at the inlet to the return pipe of the heat consumer and equipped with a condensate collector communicated via a pump with a spray device, while in order to increase the economy and fuel efficiency, a spray device placed in the duct after the condenser, and in order to increase the reliability of the system by descaling condensate saturated with carbon dioxide, the condensate collector is communicated with the heated path of the condenser through the pump (see RF patent for the invention No. 2045696, F24B 1/18, publ. 10.10. 1995).

The disadvantages of the known liquid heater are the high metal consumption and the cost of the system for heating water to a high temperature with the help of a hot-water heat generator due to the need to use expensive screen heating surfaces in the heat generator's furnace. In addition, in a contact gas-liquid heat exchanger it is impossible to heat the liquid above the saturation temperature of water, corresponding to the pressure of the combustion products. Increasing the pressure of the combustion products to increase the temperature of the heated liquid for this device necessitates a significant expenditure of energy on the compression of the gaseous oxidizer (in this case, air) and gaseous fuel (if applied), which sharply reduces the energy efficiency of the water heater. In a surface condenser of water vapor of combustion products, the temperature of heating the liquid is limited by the temperature of condensation of water vapor of the combustion products. Thus, in this system of heat recovery of combustion products, neither a contact gas-liquid heat exchanger, nor a condenser of water vapor of the combustion products can replace a heat generator with expensive screen heating surfaces when heating water to a high temperature (above the saturation temperature of the water corresponding to the pressure of the combustion products), which reduces the efficiency of heating the liquid.

Also the closest in technical essence to the proposed invention is a known combined-cycle water heater containing a vertical casing with a cylindrical wall, bottom and cover, partially filled with liquid of the first heating circuit, a heat pipe with an immersion burner and a circulation pipe coaxially placed in the casing with ring gaps relative to each other and the latter, a gas outlet and a separation device above the circulation pipe in the gap between the housing and the flame tube, while The aration device is made in the form of an annular hemispherical screen partially overlapping the gas outlet from the circulation pipe, located obliquely to the axis of the housing of the breaker and separation rings, interconnected by blades radially placed between these rings, and the down pipes connected to the lower edge of the separation rings and wound in the lower cavity of the housing, and the baffle separation rings are installed relative to each other with a gap narrowing and then expanding along the course of the combined-cycle gas flow in the first heating circuit, while the water heater is equipped with elements for input, output and circulation of the liquid in the second heated circulation circuit (see RF patent for the invention No. 2079796, F24H 1/20, publ. 05/20/1997).

A steam-gas water heater contains, as a first stage of heating a liquid, a contact heat exchanger (a submersible combustion apparatus), with which combustion products from an immersion burner are directed through a layer of liquid and heat it, and as a second stage of heating a liquid through a heated medium and a first heating medium, surface heat exchanger (expensive heat pipe), in which the plume of the submersible burner through heat transfer through the heat exchange surface carries out the final heating of the liquid.

The disadvantages of the known water heater are high metal consumption and cost, as well as significant operating costs associated with the use of a surface heat exchanger - a heat pipe operating in the zone of high temperatures of combustion products, a limited scope due to the inability to heat the liquid above the saturation temperature of the water corresponding to the pressure of the combustion products . In the case of increasing the pressure of the combustion products to increase the temperature of the heated liquid in this device, there is a need for a significant expenditure of energy on the compression of the gaseous oxidizer (in this case, air) and gaseous fuel (if applied), which sharply reduces the energy efficiency of the water heater.

Disclosure of invention

The main objective of the present invention is to increase the efficiency of heating a liquid with a high-temperature gas medium while reducing material and operating costs.

The only technical result achieved in solving this problem is to provide an increase in the temperature of heating the liquid without compressing the gaseous medium when using contact heat exchange between the heating and heated media in the high temperature zone of the gaseous medium.

The specified technical result is achieved by the fact that the method of heating the liquid includes preliminary contact heating of the liquid with a heating gaseous medium, subsequent separation of the heated liquid from the heating gaseous medium, compressing the separated heated liquid to a pressure exceeding the saturation pressure, at the required final temperature of heating the liquid, by the amount of margin non-boiling and hydraulic losses, and the final heating of the liquid, after its compression, by the heating gaseous medium, after separation from the heating liquid through the separation solid heat-exchange wall with subsequent removal of the heated liquid to the consumer.

It is advisable that either combustion products of fuel, or hot air, or hot gases of technological processes, or hot gas allowing contact heat exchange with a liquid be used as a heating gaseous medium.

The specified technical result is also achieved by the fact that in the liquid heater containing a contact heat exchanger for heating the liquid with the inlet and outlet pipelines of the heated fluid supplying and discharging ducts of the heating gaseous medium, a surface heat exchanger heating the liquid with the inlet and outlet pipelines of the heating fluid, inlet and outlet ducts of the heating of a gaseous medium, according to the invention, a device for increasing pressure and pumping liquid is introduced, to the input of which an outlet is connected hydrochloric conduit heated liquid contact heat exchanger and to the outlet - inlet line heated liquid surface heat exchanger, wherein the outlet of the heating gas flue gaseous medium contact heat exchanger is connected to a supply of the gaseous medium heating gas flue surface heat exchanger.

It is advisable that as a device for increasing pressure and pumping liquid, a pumping unit or other liquid supercharger should be used.

It is preferable that either the combustion products of the fuel, or hot air, or hot gases of technological processes, or hot gas allowing contact heat exchange with the liquid be used as a heating gaseous medium.

An increase in the pressure of the heated fluid (for example, in a device for increasing pressure and pumping the fluid), after the first stage of heating — the contact heater, allows the second stage of heating (for example, a cheap low-temperature surface heat exchanger) to heat the fluid to the required temperature exceeding the maximum temperature of the heated fluid in the contact heater, while maintaining the advantages of contact heat transfer in the high temperature zone of the heating gaseous medium.

The introduction of a device for increasing pressure and pumping liquid, the inlet of which is connected to the outlet pipe of the heated liquid from the contact heat exchanger, and to its outlet, the inlet pipe of the heated liquid of the surface heat exchanger, as well as the connection of the exhaust gas duct of the heating gaseous medium of the contact heat exchanger to the inlet gas duct of the heating gaseous medium of the surface heat exchanger allows you to get the temperature of the heated fluid above the boiling point in the contact heat exchanger without additional energy costs for compression of the gaseous medium, which increases the efficiency of the fluid heating medium at high temperature gaseous reducing material and operating costs.

The proposed method for heating the liquid is as follows.

Contact liquid heating is preliminarily carried out (for example, for technological or domestic heat supply) with a heating gaseous medium (for example, hot gases of technological processes), for example, heated liquid and hot gas are supplied to a contact heat exchanger (first heating stage), where the liquid is partially heated due to the heat of hot gases. Heated fluid is diverted from the contact heat exchanger, for example, to the inlet of the pressure increasing and pumping device, for example, a pump unit, and the heating gaseous medium is diverted, for example, to the inlet pipe of the surface heat exchanger. Increase the pressure of the heated liquid in the device for increasing the pressure and pumping the liquid to a value exceeding the saturation pressure at the required temperature of the heated liquid in the outlet pipe of the surface heat exchanger by the amount of non-boiling margin and subsequent hydraulic losses. The saturation pressure is determined by the thermophysical properties of the liquid and its temperature, and the numerical value is in the reference literature (see, for example, Thermodynamic properties of water and water vapor: Reference / Rivkin S.L., Aleksandrov A.A. - M .: Energoatomizdat , 1984, p. 7-13) or experimentally. The non-boiling stock is determined by the regulatory documents of the Gosgortekhnadzor of Russia, for example, clause 3.5.2 of the Rules for the design and safe operation of steam and hot water boilers (PB 10-574-03) provides a non-boiling stock of at least 20 ° C. Hydraulic pressure loss in the channel is determined depending on the channel configuration, mass flow rate of the medium, its physical properties according to the reference data (see, for example, Hydraulic calculation of boiler units (normative method). / Baldina OM, Lokshin VA, Peterson D.F. et al .; Edited by V.A. Lokshin et al. - M .: Energia, 1978, pp. 8-21, 60-62) or experimentally.

Then, the final heating of the liquid is carried out, after its compression, by the heating gases, after separation of the heated liquid from them, through a solid separation heat exchange wall, for example, a heated liquid is supplied from the output of the pressure increasing device and pumping liquid to the surface heat exchanger inlet (second heating stage), heating gaseous medium from a surface heat exchanger, for example, into the environment, or into an economizer (for heating a liquid in front of a contact heat exchanger or for heating another heat carrier), or an air heater, or other heat exchanger, and the heated liquid is diverted to the consumer for technological or municipal heating.

The best embodiment of the invention

The invention is illustrated in the drawing, which shows a schematic diagram of the proposed liquid heater. The positions in the drawing show the following: 1 - contact heat exchanger; 2 - inlet pipe of the heated fluid of the contact heat exchanger 1; 3 - output pipeline of the heated fluid contact heat exchanger 1; 4 - supply gas duct of the heating gaseous medium to the contact heat exchanger 1; 5 - exhaust gas duct heating gaseous medium from the contact heat exchanger 1; 6 - surface heat exchanger fluid heating; 7 - inlet pipe of the heated fluid of the surface heat exchanger 6; 8 - output pipeline of the heated fluid surface heat exchanger 6; 9 - inlet gas duct of the heating gaseous medium to the surface heat exchanger 6; 10 - exhaust gas duct heating gaseous medium from a surface heat exchanger 6; 11 - device for increasing pressure and pumping liquid.

The liquid heater contains a contact heat exchanger 1 for heating the liquid with inlet 2 and outlet 3 pipelines of the heated fluid supplying 4 and 5 exhaust ducts of the heating gaseous medium, a surface heat exchanger 6 heating fluid with the inlet 7 and outlet 8 pipelines of the heating fluid supplying 9 and the exhaust ducts 10 10 gaseous medium, a device for increasing pressure and pumping liquid 11. To the input of the device for increasing pressure and pumping liquid 11 is connected directly or through an auxiliary The second device (intended, for example, to change the mass flow rate, chemical or fractional composition, temperature or other parameters of the medium) is the outlet pipe 3 of the heated fluid from the contact heat exchanger 1, and is connected directly or through an auxiliary device to the output of the pressure boosting and pumping fluid 11 intended, for example, to change the mass flow rate, chemical or fractional composition, temperature or other parameters of the medium) the inlet pipe 7 of the heated liquid the surface heat exchanger 6. In this case, the exhaust gas duct 5 of the heating gaseous medium of the contact heat exchanger 1 is connected directly or through an auxiliary device (intended, for example, to change the mass flow rate, chemical or fractional composition, temperature or other parameters of the medium) to the supply gas duct 9 of the heating gaseous medium surface heat exchanger 6. The surface heat exchanger 6 is equipped with a discharge duct 10 for discharging a heating gaseous medium, for example, into the environment, and output pipe 8 for the output of the heated liquid for consumption.

As a contact heat exchanger 1 for heating a liquid, for example, the designs of contact liquid heaters presented in the book Sosnin Yu.P. can be used. Contact water heaters. - M: Stroyizdat, 1974, p. 241-248. Fig. 96-104, or in the book Alabovsky A.N., Udyma P.G. Devices of submersible combustion. - M.: Publishing House MPEI, 1994, p. 147, 148, Fig. 6.2, 6.3.

As a surface heat exchanger 6 for heating a liquid, for example, a design similar to a water-tube economizer used to heat the feed water of boiler units with the products of fuel combustion leaving the boiler can be used (see the book Steam Generators / Ed. By A.P. Kovalev. - M .: Energoizdat, 1985, p.26, Fig.2.1), or gas pipe (smoke) heating surface (see the book Zykov AK Steam and hot water boilers: Reference manual. - M .: Energoatomizdat, 1987, p .53, Fig. 15).

As a device for increasing pressure and pumping liquid 11, for example, a pumping unit presented in the book of Lysov KI, Grigoryev KT can be used. Pumps and pumping stations. - M .: Kolos, 1977, p. 33, fig. 15.

As a heating gaseous medium, for example, products of fuel combustion, hot air, hot gases of technological processes, or any hot gas allowing contact heat exchange with a liquid can be used.

The fluid heater operates as follows.

The heated fluid through the inlet pipe 2 is supplied to the contact heat exchanger 1 (the first heating stage), where a heating gaseous medium is also sent through the supply duct 4. Then, through the outlet pipe 3, the heated liquid is discharged from the contact heat exchanger 1 to the inlet of the liquid pressure increasing and pumping device 11, in which its pressure rises to a pressure exceeding the saturation pressure at the required temperature of the heated liquid in the outlet pipe 8 of the surface heat exchanger 6 by the non-boiling margin and subsequent hydraulic losses. After that, using the device for increasing pressure and pumping liquid 11, the heated liquid through the inlet pipe 7 is fed to the inlet of the surface heat exchanger 6 (second heating stage), into the supply duct 9 of which the heating gaseous medium comes from the exhaust duct 5 of the contact heat exchanger 1. After passage along the heat exchange surface of the heater 6, the heating gaseous medium through the exhaust gas duct 10 is removed from the surface heat exchanger 6, for example, into the environment or heat exchanger, and on retaya liquid enters the outlet conduit 8. From the outlet conduit 8 of the surface of the heat exchanger 6 the heated liquid is supplied to the consumer and can be used for industrial or municipal domestic heating.

Using the proposed method for heating a liquid and a liquid heater based on it allows to increase the energy efficiency of heating a liquid with a high-temperature gas medium while reducing material, operating costs and the level of technogenic environmental pollution.

Claims (5)

1. A method of heating a liquid, including pre-contact heating of the liquid with a heating gaseous medium, subsequent separation of the heated liquid from the heating gaseous medium, compressing the separated heated liquid to a pressure exceeding the saturation pressure, at the required final heating temperature of the liquid, by the amount of non-boiling margin and hydraulic losses , and the final heating of the liquid, after its compression, by the heating gaseous medium, after separation of the heated liquid from it, through the separation solid loobmennuyu wall, followed by withdrawal of the heated liquid consumer. 2. The method according to claim 1, characterized in that either the combustion products of the fuel, or hot air, or hot gases of technological processes, or another hot gas allowing contact heat exchange with the liquid are used as a heating gaseous medium. 3. A liquid heater comprising a contact heat exchanger (1) for heating a liquid with inlet (2) and output (3) pipelines of a heated liquid, inlet (4) and outlet (5) ducts of a heating gaseous medium, a surface heat exchanger (6) for heating the liquid with inlet (7) and outlet (8) pipelines of a heated fluid, inlet (9) and outlet (10) flues of a heating gaseous medium, characterized in that a device for increasing the pressure and pumping fluid (11) is introduced, to the input of which an outlet (3) pipeline is connected heated lumens from the contact heat exchanger (1), and the outlet (7) pipe of the heated liquid of the surface heat exchanger (6), and the outlet duct (5) of the heating gaseous medium of the contact heat exchanger (1) is connected to the inlet duct (9) of the heating gaseous medium surface heat exchanger (6). 4. The heater according to claim 3, characterized in that as a device for increasing pressure and pumping liquid, a pumping unit or other liquid supercharger is used. 5. The heater according to claim 3, characterized in that either the combustion products of the fuel, or hot air, or hot gases of technological processes, or another hot gas allowing contact heat exchange with the liquid are used as the heating gaseous medium.

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