SU1456356A1 - Method of regenerating spent heat carrier of power plants, based on nitrogen tetroxide - Google Patents

Abstract

The invention relates to the field of energy, in particular to the technology of regeneration of spent coolant of power plants based on nitrogen tetroxide, and can be used in electrical installations. In order to reduce the specific energy consumption in the method of regeneration of the spent coolant of power plants, including the conversion of nitrogen tetroxide at 200–700 ° C, mixing the proconverted gas flow with the cooled flow of liquid coolant, subsequent cooling of the gas-liquid mixture in the refrigeration unit, separation of oxygen in the coolant flow incoming to the mixture, and in the spent coolant entering the conversion, reduce the content of nitric oxide to 0.02-0.05 wt.% by rectification . The image makes it possible to reduce the specific energy consumption from an average of 37.5 kW by prototype to 8.8 kW using the proposed method for producing 1 kg of nitric oxide. 1 il. i (L

Description

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The invention relates to the power industry, in particular, to the technology of restoring the properties of a coolant, and can be used in relation to power plants operating on a coolant based on nitrogen tetroxide.

The purpose of the invention is to reduce the specific energy consumption.

The drawing shows a device for carrying out the method.

The device contains a heater 1, a superheater 2, a refrigeration unit 3, heat exchangers 4 and 5, a feeding device 6, a cube 7 of a distillation column, a distillation column 8, a reflux condenser 9, a branch pipe 10

removal of liquid from the distillation column, valves 11-15, pipelines 16-18.

The device works as follows:

The distillation column 8 is brought to the required mode of operation, with E.TOM the coolant is fed to the distillation column through the pipe 16 through the heat exchanger 4 and the valve 14. Purified from harmful impurities (HNO, Fe, etc.) using the .rification column coolant through line 17 is supplied from the dephlegmator 9 to the installation circuit. When operating a distillation column, for example, a plate type

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The plates are constantly maintained at a certain level of heat transfer fluid at saturation temperature. The valve 11 is opened and the liquid NjO with the N0 content of 0.02–0.05 May.%, Which is, for example, on the second plate of the distillation column, is fed to the inlet of the heater

1 and, pass through the superheater

is sent to the inlet of the refrigeration unit 3. In the superheater 2, N204 is converted to form a gas mixture of N0, N0, 0. The required flow rate from the distillation column to the entrance to the electric heater is set by the valve 11 using the flow meter G ,. Then the valve 12 and liquid N204 with a content of N0 at the level of 0.02 0.05 wt.% From the pipe 10 to drain the liquid from the distillation column are introduced to mix with the flow of the gas phase coolant after the superheater. Due to the fact that the coolant is sent to the regeneration with a small (at the level of 0.02-0.05 wt.%) Content of nitrogen oxide, the absorption coefficient during regeneration increases 1.2-1.3 times. The current of the liquid entering the mixture with the gas phase flow passes through heat exchangers 4 and 5 installed at the liquid outlet from the distillation column 8 and at the output of the regenerated heat carrier from the refrigeration unit 3. In the body exchanger 4 the liquid NjO flowing into the mixing with the flow the gas mixture transfers heat to the fuel carrier flow directed through pipeline 16 and valve 14 to power the distillation column 8. As a result, the temperature of the liquid taken from the distillation column 8 decreases from to ambient temperature (20-25 ° C). Then, in the heat exchanger 5, the flow of liquid N, 0 supplied to the mixture with the gas phase flow transfers heat to the supercooled regenerated coolant flow directed from the refrigeration unit 3 to the feed line of the distillation column through the heat exchanger 5 and the fan 15 by means of the feeding device 6. The temperature of the liquid entering the mixture

with the flow of the gas phase, decreases to 10 ° C, which also contributes to an increase in the absorption coefficient of nitric oxide liquid by 8-10%. The required flow rate of the liquid entering the displacement with the gas phase flow is established by the valve 12 via the flow meter G. The gas mixture (NOi, N0, Oi) obtained as a result of the conversion of Nj04 in the superheater 2 is introduced into the flow previously cooled in heat exchangers 4 and 5 with a nitrogen oxide content of 0.02-0.05 wt.% taken from the outlet 10 of the liquid and the distillation column 8. The resulting gas-liquid mixture is sent to the refrigeration unit 3, while N0 is absorbed on, forming N, 03, and goes into the liquid phase. The regenerated coolant is again sent for rectification. The released oxygen is removed from the refrigeration unit 3 through line 18 through valve 13 to the atmosphere. Reducing the content of nitric oxide below 0.02 wt.% In the coolant supplied for regeneration is impractical, since in this case the cost of obtaining such a coolant increases by 30% and the concentration of alumina oxide in the regenerated coolant remains almost unchanged. In addition, in such a coolant, the content of nitric acid increases to 2 wt.%, Which is unprofitable from the point of view of corrosion processes in the apparatus for regenerating the coolant.

It is also impractical to increase the content of nitric oxide above 0.05 wt.%, Since in this case the degree of absorption of nitric oxide by the stream of liquid nitrogen tetroxide decreases and the specific energy consumption increases.

Example 1 o In a power plant, a coolant is fed to the regeneration, the content of N0 in which is reduced by distillation from 0.95 to 0.01 wt.%. The flow rate of the conversion fluid is 4 kg / h, the flow rate of the mixture for mixing the streams in front of the cooler is 20 kg / h, and the energy consumption of the process is 6 kW / h. After regeneration of the samples, the content of N0 in the coolant is 2.85 wt.%.

Consequently, the operating time N0 is 0.6816 kg / h (0.0024 kg is the content of N0 in 24 kg of the initial heat carrier, 0.6840 - the content of N0 in 24 kg of heat carrier obtained after regeneration). The energy required to produce 1 kg of N0 is 8.8 kW.

The content of HNOj in the coolant taken from the column with a N0 content of 0.01 wt.% Is 2 wt.%. Additional cleaning of such a heat carrier from NNCO requires additional energy consumption. In particular, for purification with a distillation column of 24 kg of a heat carrier with a content of HNOj 2 wt.% To its required content (0.2 wt.%), A kW of electric power is required.

Thus, the total energy consumption for the production of 1 kg of nitric oxide, in this case, is 16.8 kW. It is known that it needs 0.2 kg / h to feed nitrogen oxide of the coolant of a small station. The station's annual need for nitric oxide is 1,752 kg. To generate this amount of N0 requires 29,433.6 kW.

Example 2. In the power plant for regeneration serves coolant, the content of N0 which is reduced by distillation to 0.02 wt.%. The flow rate of the conversion fluid is 4 kg / h, the flow rate of the liquid for mixing the streams in front of the refrigerator is 20 kg / h, and energy consumption. The costs of running the process are 6 kW / h. After regeneration, a coolant with a N0 content of 2.87 wt.% is obtained.

The operating time of nitric oxide is 0.684 kg / h, and the energy consumption for the production of 1 kg of N0 is 8.77 kW. To meet the annual demand for the N0 small station, it is necessary to spend 15368.4 kW.

Example Z. In the power plant, a coolant is supplied to the regeneration, the content of N0 in which is reduced by distillation to about 0.05% by weight. At the outlet, a heat carrier is obtained with an N0 content of 2.8 wt.%. With other things being equal (relative to examples 1 and 2), the operating time of N0 is 0.66 kg / h, and the energy consumption for the production of 1 kg of N0 is 9.1 kW. To satisfy

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In order to reduce the annual demand of the small station to N0, it is necessary to spend 15,927.27 kW.

Example 4. In the power plant for regeneration serves the coolant, the content of N0 which is reduced by distillation to 0.06 wt.%. At the outlet, a heat carrier is obtained with an N0 content of 2.5% by weight. Other things being equal (with respect to examples 1 and 2), the operating time N0 is 0.586 kg / h, and the energy consumption for the production of 1 kg NO is 10.24 kW. To meet the annual demand of a small station in N0, it is necessary to spend 17938.6 kW.

Example 5. In the power plant for regeneration serves coolant, the content of N0 which is reduced by distillation to 0.7 wt.%. At the outlet, a heat carrier is obtained with an N0 content of 2% by weight. Other things being equal (with respect to examples 1 and 2), the operating time N0 is 0.312 kg / h, and the energy consumption for the production of 1 kg NO is 19.2 kW. To satisfy the annual demand of the small station at N0, 33,692.3 kW must be spent.

Example 6 (by a known method). In the power plant for regeneration serves coolant with a content of N0 0.95 wt.%. At the outlet, a heat carrier is obtained with an N0 content of 1.62% by weight. Other things being equal (with respect to examples 1 and 2), the operating time N0 is 0.1608 kg / h, and the energy consumption for the production of 1 kg NO is 37.5 kW. To satisfy the annual demand of the small station at N0, it is necessary to spend 65,700 kW.

As can be seen from the above examples, from the point of view of energy consumption, it is most advantageous to apply a coolant with a nitrogen oxide content of 0.02-0.05 wt.% For regeneration. The use of coolant for regeneration with a different content of N0 leads to an increase in energy consumption for the process. Thus, the use of a heat carrier with a content of N0 of 0.06 wt.% (In comparison with a coolant with a content of N0 of 0.02 to 0.05 wt.%) Leads to an increase in

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Claims (1)

Claim The method of regeneration of the spent coolant of power plants based on nitrogen tetroxide, including its conversion at 200-700 ° C, mixing the converted gas stream with the cooled stream of liquid coolant based on nitrogen tetroxide, the subsequent cooling of the gas-liquid mixture in the refrigeration unit, oxygen separation, characterized in that , in order to reduce the specific energy consumption, in the cooled flow of the liquid coolant supplied to the mixture and in the spent coolant entering the conversion o, reduce the content of nitric oxide to 0.02-0.05 wt.% by rectification.