RU2544825C2 - Gas heat pump plant - Google Patents

Abstract

FIELD: power industry.SUBSTANCE: gas heat pump plant includes a compressor, a gas-liquid heat exchanger interconnected at the inlet as to cooled gas to the outlet of the compressor as to gas, a turbine interconnected at the inlet as to gas to the outlet of the gas-liquid heat exchanger as to gas, a drive unit and an intermediate gas cooler. The compressor is of a two-shaft type and consists of low and high pressure compressors interconnected with each other in a gas flow direction through a circuit of an intermediate gas cooler as to gas, the gas-liquid heat exchanger and the intermediate gas cooler are connected as to the cooling heat carrier circuit to a heating circuit of heat carrier of a heat consumer, the low pressure compressor is installed on the shaft of the drive unit and interconnected at the inlet as to gas to a cooled gas source, the high pressure compressor is installed on one shaft with a turbine equipped with a moisture removal system. Turbine 3 at the outlet as to gas is interconnected either with atmosphere or with the cooled gas consumer, or the gas heat pump plant includes a low pressure turbine installed on one shaft with low pressure compressor 6, which is equipped with the moisture removal system and interconnected at the outlet as to gas with atmosphere and/or the cooled gas consumer, and the turbine at the outlet as to gas is interconnected with the low pressure turbine inlet as to gas.EFFECT: increasing efficiency of conversion of mechanical energy to thermal energy; reducing metal consumption of the device.3 dwg

Description

The invention relates to a power system and can be applied in hot-water boiler rooms, combined heat and power plants and other facilities where there is a flue gas outlet, for utilizing the heat of condensation of water vapor contained in the flue gas for heating needs. The invention may also find application in ventilation and air conditioning systems in the summer to use the low-temperature heat removed during air cooling to heat the water supplied to the hot water supply system (DHW).

The greatest effect is expected from the use of the inventive device in the heating season during night and other periods of lowering external power consumption when using excess electricity to drive heat pump units.

State of the art

In the current practice, the network water in the heat supply system is heated in boilers or network water heaters fed by steam supplied from the heat recovery taps of steam turbines or pressure reduction coolers.

In order to avoid low-temperature corrosion of heat exchange surfaces, the minimum temperature of water at the inlet to a steel hot-water or steam gas boiler of full combustion should not be lower than 70 ° C. Accordingly, the temperature of the flue gases from gas-fired boilers is at least 110-130 ° C.

A well-known technical solution for utilizing the heat of condensation of water vapor contained in the exhaust flue gas is based on the use of condensers installed at the outlet of the flue gas from the boiler - recovery boiler (KU) or the boiler of complete combustion. A condenser is a heat exchanger, the heat exchange surface of which is drawn from bimetallic finned heat transfer elements (“Gas Condenser for Utilization of Flue Gas Heat. Energy Saving Technology”, http://www.ideasandmoney.ru/Ppt/Details/297537). Its disadvantage consists in an excessively large heat exchange surface area recruited from an expensive corrosion-resistant material (due to the small average temperature head and poor heat transfer from the gas side due to the appearance of a water film). In addition, the cooling depth of the flue gas and, accordingly, the amount of condensed water vapor are dependent on the initial temperature of the water supplied to the condenser. The temperature of the return network water increases with decreasing air temperature and in the cold period, as a rule, it is higher than the dew point of the flue gases, not allowing the heat of steam condensation to be used just at that time when the heat is most in demand.

The closest analogue (prototype) of the claimed device is a gas heat pump installation used in a thermodynamic energy storage device (www.cnrg.ru/about/presscenter/promotional%20material/SHELF-Thermodvnarnic-energy-storage.pdf "Thermodynamic energy storage as an alternative to the PSP" . - Caspian Energy Group OJSC, February 2012). Her work is based on Brighton's reverse closed loop. This gas heat pump installation (TNU) is designed to convert mechanical (electrical) energy to high temperature heat and low temperature cold and can be used to heat a liquid heat carrier (for example, network water) to the required temperature due to the transfer of heat removed from a cold source - flue gases or atmospheric air - at a much lower temperature, at which condensation of the water vapor contained in them occurs. The working fluid of the installation is air, or nitrogen, or argon, or any other gas mixture of available neutral gases.

The prototype contains (ibid., P. 7): a compressor, a gas-liquid heat exchanger communicated at the gas inlet with a gas compressor outlet, a turbine communicated at the gas inlet with a gas-gas gas exchanger outlet, and a drive unit (electric motor). The prototype also contains heat exchange equipment used to remove heat from a cold source, and a recuperator, while the gas inlet turbine is in communication with the gas-liquid heat exchanger exit through the gas through the recuperator path through the cooled gas. In the application area under consideration (heat supply, ventilation, air conditioning), a recuperator is not required, and the HPU must also contain a condenser or cooler for atmospheric air and a device for supplying cooled flue gases or air to these heat exchangers - a smoke exhauster or a fan with a drive electric motor.

The disadvantage of the prototype in this application is the insufficiently high coefficient of conversion of mechanical energy to heat (the ratio of the heat transferred to the heated coolant to the energy consumption for driving the compressor and auxiliary equipment - a smoke exhaust or fan, etc.) and an excessively large metal consumption of low-temperature heat-exchange equipment.

Disclosure of invention

The problem to which the invention is directed, is to increase the coefficient of conversion of mechanical energy to heat and reduce the metal consumption of heat-exchange equipment of gas HPI.

This problem is solved in the inventive gas HPU containing a compressor, a gas-liquid heat exchanger communicated at the inlet to the cooled gas with the compressor outlet for gas, a turbine communicated at the gas inlet with the outlet of the gas-liquid heat exchanger for gas, and a drive device. Unlike the prototype, the inventive gas ТНУ contains an intermediate gas cooler, the compressor is a twin-shaft compressor consisting of low and high pressure compressors communicated with each other along the gas path through the intermediate gas cooler path through the gas, while the gas-liquid heat exchanger and the intermediate gas cooler are included in the cooling coolant path heat consumer heat carrier circuit, low-pressure compressor mounted on the shaft of the drive unit and communicated at the gas inlet with a cooling source gas, the high-pressure compressor is installed on the same shaft with a turbine equipped with a moisture removal system, while the gas turbine at the gas outlet is either in communication with the atmosphere and / or the consumer of the chilled gas, or the gas HPU contains a low-pressure turbine mounted on the same shaft with the compressor low pressure, equipped with a dehumidification system and communicated at the gas outlet to the atmosphere or / and the consumer of the chilled gas, and the gas turbine at the gas outlet is connected to the inlet of the low pressure gas turbine.

Description of drawings

The invention is illustrated by schematic drawings, which depict:

figure 1 - gas turbine pump, a variant with one turbine, low-pressure steam drive compressor and the use of flue gases of the steam boiler as a cooled (heating) gas;

figure 2 - gas turbine engine, an option with one turbine, an electric low-pressure compressor and using atmospheric air as a cooled gas;

figure 3 - gas turbine engine, an option with two turbines, an electric low-pressure compressor and using atmospheric air as a cooled gas.

The implementation of the invention

Shown in the drawings of figures 1, 2 and 3, a gas HPP contains a compressor 1, a gas-liquid heat exchanger (GHT) 2 communicated at the inlet to the heating gas with the outlet of the compressor 1 for gas, a turbine 3 communicated at the inlet for gas with the outlet of the GHTO 2 for gas , and a drive device 4. According to the invention, the gas HPP contains an intermediate gas cooler 5, the compressor is a twin-shaft compressor consisting of low and high pressure compressors (KND 6 and KVD 7), connected to each other along the gas path through the intermediate gas cooler 5 through gas, this MTF 2 and an intermediate gas cooler (PGO) 5 is included along the cooling coolant path in the heating circuit of the heat carrier (water) of the heat consumer 8, KND 6 is installed on the shaft of the drive unit 4 and communicated at the gas inlet with the source of the cooled gas, KVD 7 is installed on the same shaft with the turbine 3 equipped with a dehumidification system.

In the embodiment of FIG. 1, the drive device is a steam turbine 4 equipped with a condenser — a steam network water heater (PPSV) 9, while PPSV 9, PGO 5 and GZhTO 2 are included along the cooling coolant path in the heating network heating circuit for external consumer 8 in series specified order. The source of the cooled gas is the steam boiler 10, and the flue gases leaving the boiler 10 are the cooled gas. The turbine 3 at the gas outlet is in communication with the atmosphere or the consumer of the chilled gas. In the variants shown in FIGS. 2 and 3, the drive device is an electric motor 4, while the PGO 5 and GZhTO 2 are included along the cooling coolant path in the water heating circuit for the hot water supply of the external consumer 8 in parallel. The source of the gas to be cooled is the environment (atmosphere), and the gas to be cooled is atmospheric air.

In the embodiment of figure 2, the turbine 3 at the gas outlet is in communication with the atmosphere and / or the consumer of the chilled gas — an air conditioning and ventilation system. In the embodiment of figure 3, the inventive gas turbine pump includes a low-pressure turbine (low-pressure turbine) 11 mounted on the same shaft as the low pressure compressor 6, equipped with a dehumidification system and communicated at the gas outlet with the atmosphere and / or the aforementioned consumer of cooled air, and turbine 3 at the outlet for gas communicated with the input of the LPI 11 for gas.

The device operates as follows.

At the KND 6 inlet, gas from an external source is supplied with a cooled gas — flue gases leaving the boiler 10 or atmospheric air, during compression of which its temperature and dew point temperature increase (i.e. the temperature below which condensation of water vapor contained in gases ) Compressed gas from KND 6 is supplied to PGO 5, where the gas is cooled with heated water, then the gas is additionally compressed in HPC 1 and cooled again in GZhT 2, transferring heat supplied to the heated water during gas compression. Further, the gas cooled in the GZhTO 2 is supplied to the turbine 3, where the gas expands and does the work of driving the HPC 7.

In the variants of figures 1 and 2, the gas in the turbine 3 expands to approximately atmospheric pressure, cooling to a low temperature. If there is water vapor in the cooled gas, it will condense all or most of it not in PGO 5 and GZhTO 2 (as in a condenser), but in turbine 3, while the heat of condensation of water vapor released slows down the temperature of the working fluid (gas phase) in the process its expansion and thereby increases the power of the turbine 3. The work performed by the chilled gas in the turbine 3 in the variants of gas HPP with one gas turbine (Fig. 1 and Fig. 2) is spent only on the HPC drive 7.

In the embodiment of FIG. 3, gas from the turbine 3 is supplied to the high pressure fuel pump 11, the expansion work of the chilled gas in this embodiment is distributed between the shafts of the HPC 7 and KPI 6 so that, at an optimal (sufficiently small) level of compression in the KPI 6, the gas temperature behind the KPI 6 and KVD 7 would be about the same. In this case, the installation of the high pressure pump 11 on the KND 6 shaft provides an additional increase in the coefficient of conversion of supplied mechanical energy to heat.

Condensate is removed from the flow part of the turbine (turbines) and from the wet gas stream behind the turbine (s) through moisture removal systems known from the technical level - devices for collecting, separating and removing moisture from the turbine flow part and behind the turbine, which are widely used in humid-steam turbines (A .V. Shcheglyaev, Steam Turbines, Book 1. - M .: Energoatomizdat, 1993, p.335-338).

Thus, in the inventive gas HPI, an open Brighton cycle is implemented with intermediate cooling of the compressible gas, and in the presence of water vapor in the gas, it also heats the working fluid during its expansion by the heat of condensation of water vapor. The required temperature increase in compressors is less than in the prototype by the value of the temperature head in low-temperature heat exchangers. The result is a significant increase in the coefficient of conversion of mechanical energy into heat in comparison with the prototype.

The absence of low-temperature heat transfer and related auxiliary equipment provides a significant reduction in the metal consumption of the inventive gas HPU compared with the prototype.

The examples shown in figures 1, 2 and 3 are presented to illustrate the claimed invention in the most visual form with both alternative distinguishing features (with one or two turbines), different sources of cooled (heating) gas and do not exhaust all possible options for its implementation. In particular, the source of flue gases can be not only a conventional boiler, but also a gas turbine installation, a gas engine, a waste heat boiler, a chimney, a flue gas collector of a group of boilers, etc. In the embodiment of FIG. 1, in KND 6, not all of the source exhaust gas flow can be supplied, but only a part of it, while PGO 5 and GZhTO 2 can be included in the heating water supply circuit not sequentially, but in parallel, and not before, but before 9 (at a sufficiently high temperature of the return network water). The driving device 4 may be not only a steam turbine or electric motor, but also any other engine (gas turbine, gas piston engine), etc. etc.

Claims (1)

A gas heat pump installation comprising a compressor, a gas-liquid heat exchanger communicated at the gas inlet inlet with a gas compressor outlet, a turbine communicated at a gas inlet with a gas-gas heat exchanger outlet in gas, and a drive device, characterized in that the inventive gas heat pump installation contains an intermediate gas cooler, the compressor is made of a two-shaft, consisting of low and high pressure compressors communicated with each other along the gas path through the intermediate gas cooler path dividing by gas, while the gas-liquid heat exchanger and the intermediate gas cooler are connected through the cooling coolant path to the heating circuit of the heat consumer, the low-pressure compressor is installed on the shaft of the drive unit and communicated at the gas inlet with the source of the cooled gas, the high-pressure compressor is installed on one shaft with a turbine equipped with a dehumidification system, while the turbine at the gas outlet is in communication with either the atmosphere and / or the consumer of the chilled gas, or the gas heat pump The assembly contains a low-pressure turbine mounted on one shaft with a low-pressure compressor, equipped with a dehumidification system and communicated at the gas outlet with the atmosphere and / or the consumer of the chilled gas, and the gas turbine at the gas outlet is in communication with the inlet of the low-pressure gas turbine.

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