KR101298543B1 - Apparatus and Method for Treating Waste Gas - Google Patents

Abstract

Provided is a combustion exhaust gas treating apparatus and method configured to liquefy and separate harmful components such as carbon dioxide or nitrogen oxide contained in combustion exhaust gas through a press-cooling method.

The combustion exhaust gas treatment apparatus includes a compressor for pressurizing combustion exhaust gas, a main heat exchanger for recovering cold heat from the pressurized combustion exhaust gas associated with the compressor, and a combustion exhaust gas for which cold heat is recovered in association with the main heat exchanger It includes a liquefaction means for liquefying and separating the harmful components of, and a turbine associated with the compressor and the pressure energy associated with the liquefaction means to recover the pressure energy contained in the combustion exhaust gas separated from the harmful components.

According to the present invention, it is possible to discharge the combustion pollutants emitted from various combustion furnaces through mechanical compression liquefaction process using a minimum amount of energy to discharge the environmental pollutants of the epidemic component by the combustion of fossil fuels. An improved effect can be obtained that allows for maximum inhibition.

Combustion exhaust gases, harmful components, pressurized, cooled, liquefied, carbon dioxide, nitrogen oxides

Description

Apparatus and Method for Treating Waste Gas

1 is a block diagram of a combustion exhaust gas treatment apparatus according to the present invention

Description of the Related Art [0002]

1 .... Combustion Emissions Treatment System 10,10 ', 10 ", 10a, 10b .... Combustion Emissions

20 .... Compressor 30 .... Evaporator

40 .... Organic Rankine Cycle Apparatus 42 .... Working Fluid

44 .... Organic Turbine 46 .... Generator

48 .... condenser 50 .... main heat exchanger

52 .... Auxiliary Heat Exchanger 60 .... Expansion Turbine

70 .... Liquefaction means 80 ... Power recovery turbine

82 .... Axis

The present invention relates to a combustion exhaust gas treatment device, and more particularly, to exhaust the combustion exhaust gas discharged from various combustion furnaces through a mechanical compression liquefaction process using a minimum amount of energy. The present invention relates to a combustion exhaust gas treatment apparatus and method for suppressing the emission of environmental pollutants as much as possible, thereby eliminating the problem of global warming gas emissions.

Most of the energy necessary to maintain human civilization is obtained by the burning of fossil fuels, except in exceptional cases.

However, in the combustion of such fossil fuels, the generation of combustion products such as nitrogen oxides and carbon dioxide is essential.

At present, such combustion products are acting as a major factor in air pollution and global warming, and their severity is gradually accelerating.

In particular, since the amount of environmental pollutants such as carbon dioxide emitted from large combustion furnaces such as power generation boilers is considerable, intensive studies on the treatment techniques of such environmental pollutants have been conducted and related technologies have been proposed.

For example, known representative techniques for removing environmental pollutants such as carbon dioxide contained in combustion exhaust gas include a pressure swing adsorption (PSA) method or an absorption removal method using an absorbent liquid.

In such a removal method, nitrogen oxides are mainly removed through the use of activated carbon.

In other words, these techniques utilize common technical features to separate and remove harmful combustion products using intermediate media such as adsorbents or absorbents.

However, this known conventional PSA or absorbent removal method is substantially costly because of the need to periodically replace the absorbent or adsorbent material for removal of the noxious combustion products.

In particular, there is a problem in that the application is disadvantageous in the operating environment in which the exhaust gas must be treated continuously without stopping the equipment.

Therefore, in an actual industrial process, the method of separating the harmful substances in the exhaust gas by the configuration of a mechanical device without the need for an intermediate medium for separation is most desirable.

Accordingly, the present invention proposes an exhaust gas treatment apparatus that effectively treats exhaust gas continuously without interruption by using only mechanical device configuration by applying the principle of liquefaction by compression-cooling and without using intermediate media such as absorbent material. Such a device has been required.

The present invention has been made to solve the conventional problems as described above, the object of which is to discharge the combustion exhaust gas discharged from various combustion furnaces through a mechanical compression-liquefaction process using a minimum of energy, the fossil fuel An object of the present invention is to provide a combustion exhaust gas treating apparatus and method for suppressing the emission of environmental pollutants caused by combustion as much as possible, thereby preventing the emission of gases that cause global warming.

The present invention as a technical aspect for achieving the above object, a compressor for pressurizing the combustion exhaust gas;

A main heat exchanger associated with the compressor and recovering cold heat from pressurized combustion exhaust gas;

Liquefaction means associated with the main heat exchanger to liquefy and separate toxic components of combustion exhaust gas from which cold heat is recovered; And

A power recovery turbine associated with the liquefaction means and recovering the pressure energy contained in the combustion exhaust gas in which noxious components are separated, and connected to the compressor;

It provides a combustion exhaust gas treatment apparatus configured to liquefy to separate the harmful components of the combustion exhaust gas, including.

At this time, the organic Rankine cycle device may be linked between the compressor and the main heat exchanger via an evaporator.

Preferably, the organic Rankine cycle apparatus is configured such that the working fluid receiving heat through the evaporator is vaporized by the high temperature combustion exhaust gas, the organic medium turbine and the generator driving through the working fluid, and the organic medium turbine It may include a condenser for liquefying the expanded working fluid in the evaporator and may be configured in a cycle form.

In addition, an auxiliary heat exchanger is disposed between the main heat exchanger and the liquefaction means, and in the auxiliary heat exchanger, an expansion turbine for cooling the combustion exhaust gas to the liquefaction temperature through expansion with the compressor is further connected.

In this case, the liquefaction means is provided as a separation vessel for liquefying and separating the harmful components of carbon dioxide and nitrogen oxides contained in the combustion exhaust gas cooled to the liquefiable temperature while passing through at least one of the main heat exchanger and the expansion turbine and the auxiliary heat exchanger. It is possible.

In another aspect, the present invention is to recover the heat of compression generated by compressing the combustion exhaust gas in the compressor as the operating heat source of the organic Rankine cycle apparatus,

The compressed combustion exhaust gas is recovered by cold heat using a main heat exchanger, and toxic components contained in the combustion exhaust gas are liquefied by the liquefaction means.

Provided is a combustion exhaust gas treatment method for recovering pressure energy contained in combustion exhaust gas in which harmful components are liquefied for power of a turbine directly connected to the compressor, and liquefying and separating harmful components contained in combustion exhaust gas with minimum energy.

At this time, the combustion exhaust gas pressurized by the compressor to increase the temperature is transferred to the working fluid of the organic Rankine cycle unit in the evaporator mediated between the compressor and the organic Rankine cycle unit, and cooled to a liquefiable temperature while passing through the main heat exchanger It is preferable that the harmful components of the carbon oxides and nitrogen oxides are separated from the liquefaction means and discharged to the outside.

More preferably, some of the combustion exhaust gas delivered from the evaporator to the main heat exchanger is cooled to a temperature necessary for liquefaction through an expansion process in the expansion turbine so that harmful components of carbon dioxide and nitrogen oxides are liquefied and discharged from the associated liquefaction means. It is.

Alternatively, the combustion exhaust gas passing through at least one of the main heat exchanger and the expansion turbine further promotes liquefaction of harmful components through an auxiliary heat exchanger further disposed between the main heat exchanger and the liquefaction means, and the liquefaction means separates the toxic components from the liquefied separation. It can be unified.

The residual combustion exhaust gas in which the toxic components are liquefied and separated is subjected to heat exchange again in the main heat exchanger, and after the power is recovered from the power recovery turbine, the low pressure and the low pressure components decompressed to atmospheric pressure are finally separated. Discharged.

Hereinafter, the present invention will be described.

First, carbon dioxide and nitrogen oxide, which are representative hazardous environmental pollutants contained in combustion exhaust gas generated from a combustion facility such as a power plant for burning fossil fuel, can be liquefied at high temperature and low pressure.

For example, in the case of carbon dioxide, the critical pressure and temperature are 74 bar and 31 ° C., respectively, and the lower the temperature, the lower the pressure that enables liquefaction.

If the temperature is about -50 ℃, carbon dioxide can be liquefied at 10 atmospheres.

Therefore, in the present invention, the combustion exhaust gas is first compressed in the apparatus by using such a phenomenon, that is, liquefied carbon dioxide.

Next, a portion of the compressed combustion exhaust gas is expanded to obtain cold heat, and the combustion exhaust gas temperature is lowered by using the same to liquefy and separate toxic combustion products such as carbon dioxide and nitrogen oxides.

In this case, of course, the pressure and temperature of the combustion exhaust gas can be selected to the optimum range depending on the installation conditions of the device.

In addition, the compression power required for the compression of the combustion exhaust gas and the heat of compression generated during the compression process can be recovered by using a power recovery turbine and an organic Rankine power generation unit, thereby compressing and liquefying the combustion exhaust gas using minimal energy. Let's do it.

Hereinafter, a preferred embodiment of the present invention according to the accompanying drawings in more detail as follows.

First, in FIG. 1, the whole structure of the combustion waste gas processing apparatus 1 which concerns on this invention is shown.

That is, as shown in FIG. 1, the combustion exhaust gas 10 discharged from a combustion facility (not shown) such as a power plant that burns fossil fuel is typically at a temperature of about 200 ° C., and this combustion exhaust gas 10 is provided. Pressurizes to the required pressure using the compressor 20.

At this time, reference numeral 22 denotes a compressor operating motor, which is connected to the shaft 82 and the power recovery turbine 80 described below, not the compressor main power source, so that the compressor main power source is transmitted.

Therefore, when the combustion exhaust gas 10 introduced from the compressor 20 is pressurized, the temperature of the combustion exhaust gas 10 is increased.

Next, the combustion exhaust gas pressurized by the compressor 20 at a high temperature and a high pressure transfers heat to the working fluid 42 of the organic Rankine cycle apparatus 40 through the connected evaporator 30.

Subsequently, the combustion exhaust gas 10 ′ in the state of being heated and cooled in the evaporator 30 is further cooled to a temperature at which liquefaction is possible while passing through the main heat exchanger 50.

At this time, in the evaporator 30, the working fluid 42 is vaporized by the heat transfer of the compressed high-temperature combustion exhaust gas 10 '.

Accordingly, the vaporized working fluid 42 generates a power source for driving the organic medium turbine 44 and the generator 46 while implementing the cycle.

In addition, the working fluid 42 expanded in the organic medium turbine 44 is liquefied in the condenser 48 and then boosted in the pump P to implement a cycle that is sent back to the evaporator 30.

Therefore, through the organic Rankine cycle device 40, the heat loss generated during the compression process of the combustion exhaust gas 10 can be recovered to the power again.

In particular, the process of compressing and increasing the temperature of the combustion exhaust gas 10 at a temperature of 200 ° C. is a temperature raising process in a heat pump, and in view of the organic Rankine cycle, the working fluid 42 in the evaporator 30 by combustion or other methods. Compared to obtaining the heat of evaporation, the advantage of generating the combustion exhaust gas 10 pressurized to a higher temperature more efficiently can be obtained.

Next, as shown in FIG. 1, the portion 10 ″ of the combustion exhaust gas cooled while being heated through the evaporator 30 is subjected to the expansion process in the expansion turbine 60 branched before the main heat exchanger 50. It is further cooled to the temperature required for liquefaction.

The combustion exhaust gas 10 'cooled through the main heat exchanger 50 is also cooled to a temperature necessary for liquefaction.

Next, as shown in FIG. 1, the cooled combustion exhaust gas 10 ′ having passed through the evaporator 30 is passed through the main heat exchanger 50 to the separator, which is the liquefaction means 70, before being transferred to the secondary heat exchanger ( 52, further cooled, and at the same time the low-temperature, high-pressure combustion exhaust gas 10 "cooled by the expansion turbine 60 also before the auxiliary heat exchanger 52 before reaching the separation vessel, the liquefaction means 70. It is cooled more while going through.

Therefore, harmful components such as carbon dioxide and nitrogen oxide contained in the cooled combustion exhaust gases 10 'and 10 " are liquefied in a separator, which is the liquefaction means 70, and are discharged after they are accumulated under their own gravity by their own gravity. Externally discharged through the pipe (72).

Next, the combustion exhaust gas 10a in which toxic components such as carbon dioxide and nitrogen oxide discharged from the liquefaction means 70 are liquefied and separated through heat exchange again in the main heat exchanger 50, and then, in the power recovery turbine 80. Swell.

After the power is recovered in this process, the low pressure combustion exhaust gas (gas in which carbon dioxide and the like is liquefied) 10b is finally discharged.

In this case, the shaft 82 of the power recovery turbine 80 is directly connected to the compressor 20 in which the first continuous exhaust gas is introduced and pressurized from the front.

Therefore, the power required to compress the combustion exhaust gas 10 in the compressor can be provided by the apparatus 1 itself, so that the required energy is minimized.

On the other hand, the motor 22 connected to the compressor 20 may additionally be provided as an auxiliary power source for generating compressed power if necessary.

Therefore, in the case of the combustion exhaust gas treating apparatus 1 of the present invention, the power required for the compression of the combustion exhaust gas 10 can be recovered through the power recovery turbine 80.

In addition, the heat loss generated during the compression process is recovered by applying the organic Rankine cycle, and the cold heat held by the low-temperature combustion exhaust gas is also recovered through the main heat exchanger 50, thereby generating the compression-cooling-liquefaction process. It is possible to make the whole system operate even if only the loss heat is compensated.

Thus, according to the combustion exhaust gas treatment apparatus and method of the present invention, by causing the combustion exhaust gas discharged from various combustion furnaces to be discharged through a mechanical compression-liquefaction process using a minimum of energy, environmental pollution by burning fossil fuel It is to provide a combustion exhaust gas treatment apparatus which suppresses the emission of materials as much as possible and thereby prevents the emission of gases that cause global warming.

While the invention has been shown and described in connection with specific embodiments so far, it will be appreciated that the invention can be varied and modified without departing from the spirit or scope of the invention as set forth in the claims below. It will be appreciated that those skilled in the art can easily know.

Claims (10)

A compressor for pressurizing combustion exhaust gas; A main heat exchanger associated with the compressor and recovering cold heat from pressurized combustion exhaust gas; Liquefaction means associated with the main heat exchanger to liquefy and separate toxic components of combustion exhaust gas from which cold heat is recovered; And A power recovery turbine associated with the liquefaction means and recovering the pressure energy contained in the combustion exhaust gas in which noxious components are separated, and connected to the compressor; Combustion exhaust gas treatment device configured to liquefy and separate the harmful components of the combustion exhaust gas, including. The combustion exhaust gas treating apparatus according to claim 1, wherein an organic Rankine cycle apparatus is connected between the compressor and the main heat exchanger via an evaporator. The organic Rankine cycle apparatus according to claim 2, wherein the organic Rankine cycle device is configured such that a working fluid receiving heat through an evaporator is vaporized by a high temperature combustion exhaust gas, and an organic medium turbine and a generator driving through the working fluid, and organic A combustion exhaust gas treatment apparatus comprising a condenser for liquefying an expanded working fluid in a media turbine and configured in a cycle form with an evaporator. The method of claim 1, wherein an auxiliary heat exchanger is disposed between the main heat exchanger and the liquefaction means, and the auxiliary heat exchanger is further associated with an expansion turbine for cooling the combustion exhaust gas to the liquefaction temperature through expansion with the compressor. Combustion exhaust gas treatment device. The liquefaction means according to claim 1 or 4, wherein the liquefaction means includes harmful components of carbon dioxide and nitrogen oxide contained in combustion exhaust gas cooled to a liquefiable temperature while passing through at least one of the main heat exchanger and the expansion turbine and the auxiliary heat exchanger. Combustion exhaust gas treatment apparatus, characterized in that consisting of a separator for liquefied separation. Compressed heat generated by compressing the combustion exhaust gas in the compressor is recovered as axial power by using as an operating heat source of the organic Rankine cycle apparatus. The compressed combustion exhaust gas is recovered by cold heat using a main heat exchanger, and toxic components contained in the combustion exhaust gas are liquefied by the liquefaction means. A combustion exhaust gas treatment method for recovering pressure energy contained in combustion exhaust gas in which noxious components are liquefied, for power of a turbine directly connected to the compressor, and liquefying and separating the noxious components contained in combustion exhaust gas with only minimal energy. 7. The combustion exhaust gas pressurized by the compressor to be elevated in temperature is capable of transferring heat to the working fluid of the organic Rankine cycle apparatus in an evaporator mediated between the compressor and the organic Rankine cycle apparatus, and liquefied while passing through the main heat exchanger. The combustion exhaust gas treatment method characterized in that the harmful components of carbon dioxide and nitrogen oxides are separated from the liquefaction means and discharged to the outside while being cooled to a temperature. The method of claim 7, wherein a part of the combustion exhaust gas delivered from the evaporator to the main heat exchanger is cooled to the temperature required for liquefaction through the expansion process in the expansion turbine, so that harmful components of carbon dioxide and nitrogen oxides are liquefied separated from the associated liquefaction means and the external discharge Combustion exhaust gas treatment method characterized in that. The combustion exhaust gas passing through at least one of the main heat exchanger and the expansion turbine further promotes liquefaction of harmful components through an auxiliary heat exchanger further disposed between the main heat exchanger and the liquefaction means. The liquefaction means is a combustion exhaust gas treatment method, characterized in that the separation component is liquefied separation of harmful components. 9. The method of claim 8, wherein the residual combustion exhaust gas in which the toxic components are liquefied and separated is subjected to heat exchange again in the main heat exchanger, and after the power is recovered from the power recovery turbine, the low pressure state and the harmful components separated to atmospheric pressure are separated. Combustion gas treatment method characterized in that the gas of the final discharge.

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