KR20230035547A - By Pre-Condensate Evaporation Heat, Oxyfuel Combustor Exhaust Gas Cooling Heat Recovery and CO2 Capture Device, and Its Heat Pump and Net Zero Operation Method of Gas-Boiler Steam Turbine Power Plant - Google Patents

Abstract

The present invention relates to a CO_2 capture device and an operation method thereof for carbon neutrality (CO_2 net zero) in a gas boiler of a thermal power plant, wherein circulating steam as a working fluid is recycled to a combustion chamber and pure oxygen combustion is realized, so that CO_2 is captured; 80 mol% of circulating steam and 20 mol% of steam produced by combustion, which are exhausted from the combustion chamber, are cooled and condensed, and the pre-condensate as a refrigerant cools exhaust gas entering the combustion chamber with huge evaporation heat and absorbs and cools the huge condensation heat of the exhaust gas, so that the exhaust gas is cooled and condensed; and the pre-condensate is heated to 90℃ steam, all the exhaust heat from the combustion chamber is recovered by means of a heat pump, CO_2 is captured, and therefore carbon neutrality is realized.

Description

Thermal Power Plant Exhaust Cooling Exhaust Heat Recovery and CO2 Capture Device, Heat Pump and Carbon Neutral Operation Method {By Pre-Condensate Evaporation Heat, Oxyfuel Combustor Exhaust Gas Cooling Heat Recovery and CO2 Capture Device, and Its Heat Pump and Net Zero Operation Method of Gas-Boiler Steam Turbine Power Plant}

The present invention relates to a CO ₂ capture device and an operating method thereof for carbon (CO ₂ Net Zero) neutralization in a gas boiler of a thermal power plant, and circulating steam as a working fluid is (8H ₂ O + 2O ₂ + CH ₄ = 8H ₂ O + CO ₂ + 2H ₂ O), recirculated to the combustion chamber, pure oxygen combustion is realized, CO ₂ is captured, and 80 mol% of circulating steam (working fluid) exhausted from the combustion chamber and 20 mol produced by combustion % steam becomes cooling condensate, and this (group-plural) gas condensate cools the combustion chamber inlet exhaust with enormous evaporation heat as a refrigerant, absorbs and cools the enormous (condensation) condensation heat of this (steam) exhaust, and this exhaust is cooled condensate, and this condensate is heated to 90°C with steam, and by means of a heat pump, all exhaust heat from the combustion chamber is recovered, and carbon neutrality is realized by collecting CO ₂ .

Nitrogen in the air is about 78%, oxygen 21%, and other (CO ₂ , argon, etc.) 1%. In gas turbines, NG is usually air-combusted as fuel. Therefore, it was not easy to capture carbon dioxide (CO ₂ ) due to nitrogen (78%) during combustion chamber exhaust. In order to solve this problem, oxy-combustion has recently been studied. In other words, if pure oxygen is injected into the combustion chamber instead of air, the combustion chamber exhaust consists of only steam and CO ₂ , so it is a study to recover the steam generated by cooling the exhaust and easily capture CO ₂ . This pure oxy-combustion became a new problem of overheating of the combustion chamber as the working fluid decreased as nitrogen was removed. Therefore, in order to solve the problem of overheating of the combustion chamber, steam as a working fluid must be circulated into the combustion chamber as in the gas turbine CES cycle, or CO ₂ must be recycled into the combustion chamber as in the Allam cycle.

In coal-fired power plants, pulverized coal is usually injected into the boiler combustion chamber along with air. Therefore, environmental pollutants such as coal dust, fine dust, and sulfur oxides are inevitably discharged during exhaust from the combustion chamber. To solve this problem, if a gas boiler is used instead of a coal boiler, and circulating steam as a working fluid is recycled to the combustion chamber for pure oxygen combustion, carbon neutrality can be realized, but this steam cannot be found in any gas. There is a characteristic of an enormous condensation heat without condensation, so there is a problem that is not easily condensed, and also, as in a steam turbine condenser, the problem of loss of up to 50% of the exhaust heat from the combustion chamber must be solved.

It is known that carbon dioxide (CO ₂ ) dissolves relatively well in seawater and dissolves better when pressure is applied at a lower temperature. Recently, a technology has been developed to produce electricity and hydrogen by dissolving this CO ₂ into carbonated water. Hydrogen has a very low boiling point of -252.87℃, so commercial hydrogen is not produced as a liquid, but is usually compressed at high pressure and used. Ammonia (NH ₃ ), which is a colorless gas at room temperature and is mainly used as a raw material for fertilizer, has a boiling point of -33.34 ° C and is liquefied at a low pressure (8.6 bar) at room temperature (20 ° C). This NH ₃ has been conventionally produced at high temperature and high pressure (200 bar at 450° C.), but recently (UNIST), a new technology for producing at 45° C. at 1 atm has been developed at the Ulsan Institute of Science and Technology. Due to these characteristics, it has recently been actively studied as a medium for storing and transporting hydrogen. In other words, it is a technology that does not pollute the environment by utilizing nitrogen, which is 78% of the air, to make NH ₃ and store it, then extract hydrogen from NH ₃ and release nitrogen back into the atmosphere. In addition, 1.5 times more hydrogen is stored in NH ₃ than in liquid. Also recently, at the Korea Advanced Institute of Science and Technology (KIST), a hydrogen extractor has been developed that separates this hydrogen from nitrogen from NH ₃ at a temperature below 450 °C using a catalyst and a membrane device. In other words, it shows the possibility of a future new technology that stores hydrogen in a storage container (NH ₃ ) at a low pressure (8.6 bar) at 1.5 times that of liquid, and can easily take the hydrogen out of the storage container and use it.

In the present invention, in order to easily capture carbon dioxide (CO ₂ ), only pure oxygen is injected into the combustion chamber, pure oxygen combustion is implemented, and steam is condensed, as in a steam turbine condenser, exhaust heat is recovered, and CO ₂ is returned to the atmosphere. It is collected so that it is not released.

Coal-fired boilers in thermal power plants generate not only carbon dioxide (CO ₂ ) but also coal dust, fine dust, and sulfur oxides, which are then released into the atmosphere. If a gas boiler is used instead of this coal boiler, coal dust and fine dust are not emitted.

In a thermal power plant, CO ₂ , the main culprit of global warming, is continuously generated in an extremely large amount due to the combustion of fuel. Therefore, carbon (CO ₂ Net Zero) neutrality is essential. This CO ₂ constantly generated in the combustion chamber must be captured so that this carbon neutrality can be realized.

In order to achieve carbon (CO ₂ Net Zero) neutrality, oxy-combustion must be realized and CO ₂ must be easily captured. For this oxy-combustion, steam must be recycled to the combustion chamber or CO2 must be recycled. In the present invention, steam as the working fluid, (8H ₂ O + 2O ₂ + CH ₄ = 8H ₂ O + CO ₂ + 2H ₂ O), is recycled to the combustion chamber, and this steam is condensed, as in a steam turbine, 50% Emission losses up to However, this circulating steam has a characteristic of enormous heat of condensation not found in any gas, and it is impossible to recover this exhaust without using seawater by ordinary heat exchange methods.

In the present invention, in a thermal power plant, a gas boiler is used instead of a coal boiler, and oxygen and nitrogen are produced separately from air so that carbon (CO ₂ Net Zero) neutrality is realized, used as a refrigerant, and only pure oxygen is injected into the combustion chamber. , and circulating water (steam) as a working fluid is recirculated to the combustion chamber, (8H ₂ O + 2O ₂ + CH ₄ = 8H ₂ O + CO ₂ + 2H ₂ O), realizing pure oxygen combustion, While maintaining a constant operating pressure, the exhaust from the combustion chamber is (suctioned) introduced into the special heat exchanger of the present invention (exhaust cooler) with a back pressure of 0.2 bar or less, is cooled with oxygen as a refrigerant, condensation of steam in the exhaust gas, condensation heat of the enormous steam is absorbed as steam-condensation heat of vaporization, all of this exhaust heat is recovered, CO ₂ in the exhaust gas is collected at -13°C, and the above carbon neutrality is realized. do.

The combustion chamber (steam) exhaust is characterized by enormous (atmospheric pressure 539 kcal/kg) condensation heat, so it is not easily cooled, but this enormous condensation heat is utilized as evaporation heat (as cooling heat) (as a refrigerant), leading (exhaust) steam is cooled and condensed, (fresh condensate) gas-condensate, with enormous evaporation heat, cools the subsequent exhaust, this combustion chamber exhaust becomes cooled condensate, and this gas-condensate absorbs the (condensate) condensation heat of the enormous steam and turns it into 90 ° C steam The entire amount of exhaust heat of this steam is recovered by means of temperature raising and heat pump.

In this way, the combustion chamber exhaust is introduced (intake) into the exhaust cooler at a back pressure of 0.2 bar, and steam is condensed, and this group-condensation cools the subsequent (exhaust) steam with enormous heat of evaporation and raises the temperature to 90 ° C steam. In order to do this, since a constant operating pressure of 1 atm or more must be maintained in the combustion chamber, the gas boiler combustion chamber exhaust is discharged through the power generator of the present invention (special exhaust device), and this exhaust is (suctioned) to the present exhaust cooler at a back pressure of 0.2 bar. is introduced

In this way, the combustion chamber exhaust is introduced (intake) into the exhaust cooler at a back pressure of 0.2 bar, and steam is condensed, and this group-condensation cools the subsequent (exhaust) steam with enormous heat of evaporation and raises the temperature to 90 ° C steam. In order to do this, since a constant operating pressure of 1 atm or more must be maintained in the combustion chamber, the gas boiler combustion chamber exhaust is discharged through the power generator of the present invention (special exhaust device), and this exhaust is (suctioned) to the present exhaust cooler at a back pressure of 0.2 bar. is introduced

In the present invention, in the gas boiler of a thermal power plant, the preceding exhaust gas-condensate cools the exhaust heat following (steam) of the combustion chamber with enormous evaporation heat and absorbs the exhaust heat as evaporation heat, so that the entire amount of this enormous exhaust heat is recovered, and furthermore, Hydrogen is produced from CO ₂ , and ammonia (NH ₃ ) is produced from this hydrogen and nitrogen used as a refrigerant, and eventually, hydrogen is produced from CO ₂ , and 1.5 parts of the liquid are stored in this NH ₃ , It is characterized by being configured to realize carbon (CO ₂ Net Nero) neutrality.

FIG. 1 is a flow diagram showing the flow of a working fluid, showing that exhaust gas from a combustion chamber of a gas boiler is cooled in a plurality of (preceding exhaust) phases, so that exhaust heat is completely recovered and CO ₂ is captured.
2 is a diagram showing the structure of the present exhaust cooler symbolically showing that exhaust gas from a combustion chamber of a gas boiler is introduced (intake) into the exhaust cooler of the present invention to be cooled, vapor is condensed, and CO ₂ is collected at a low temperature of -13 ° C. .
3 is a view showing the shape of a main part of a blade for collecting and discharging non-condensable gas such as oxygen in the present exhaust cooler.
4 is a flow diagram showing the flow of a working fluid in a nitrogen liquefaction cooling system, showing a process in which nitrogen is cooled and liquefied.
Fig. 5 is a flow diagram showing a process in which exhaust heat (of the combustion chamber) absorbed as evaporation heat by (group-plural) fresh condensate as refrigerant is recovered by means of a heat pump.
6 is a view showing the shape of a main part of a power generator in which a pressure of 1 atm or more is maintained in a sealed state of the boiler combustion chamber, and power is produced and discharged at a back pressure of 0.2 bar while exhaust from the combustion chamber is discharged.
7 is a view showing the shape of general, Lobe pumps used in the power generator of the present invention.

1 is a flow diagram showing the flow of a working fluid, showing that (steam) exhaust from a gas boiler of a thermal power plant is refrigerated in a ki-plural (of a preceding exhaust), its exhaust heat is recovered, and CO ₂ is captured. . In the present invention, for carbon (CO ₂ Net Zero) neutrality, 80 mol% of circulating water (steam) as a working fluid, (8H ₂ O + 2O ₂ + CH ₄ = 8H ₂ O + CO ₂ + 2H ₂ O), It is recirculated to the combustion chamber to realize pure oxy-combustion, and therefore, the combustion chamber exhaust consists of 80 mol% steam as a working fluid, 20 mol% generated steam, and 10 mol% CO ₂ . Exhaust from the combustion chamber is sucked in with the exhaust cooler of the present invention at a back pressure of 0.2 bar and 110 ° C, and the condensate (the group of the preceding exhaust) uses the enormous evaporation heat as cooling heat as a refrigerant and evaporates into steam while entering the combustion chamber. In addition to cooling the exhaust, the liquid refrigerant oxygen further cools it, and the steam in this combustion chamber exhaust is cooled to 60 ° C at 0.2 bar, and this condensate, as a refrigerant, cools the subsequent (steam) exhaust, its enormous ( Plural) Condensation heat is absorbed as enormous evaporation heat, the temperature is raised to 90℃ steam, and CO ₂ generated by combustion is discharged (collected) at -13℃. The exhaust heat from the combustion chamber absorbed by this gas and condensate is then recovered in its entirety by means of a heat pump. Figure 2 is a diagram symbolically showing the structure of the exhaust cooler of the present invention, the combustion chamber exhaust is sucked into the exhaust cooler, and in the exhaust heat absorber at the inlet, the gas-condensate is converted into enormous evaporation heat as a refrigerant, refrigerant oxygen and In addition, the combustion chamber exhaust is cooled, evaporated into steam to absorb the exhaust heat thereof, and the temperature is raised to 90°C. In FIG. 2, CO ₂ produced by combustion is discharged (captured) at -13°C.

In the present invention, for carbon neutrality, CO ₂ generated by (fuel NG) combustion is captured and not released to the atmosphere by pure oxygen combustion, and circulating steam as a working fluid is (8H ₂ O + 2O ₂ + CH ₄ = 8H ₂ O + CO ₂ + 2H ₂ O), which is recycled to the combustion chamber, realizing pure oxygen combustion. This circulating steam and the generated (80+20) 100 mol% steam are cooled and condensed in this exhaust cooler, and all of this exhaust heat is recovered. Steam has a characteristic of enormous condensation heat that cannot be seen in any gas. In all steam turbines around the world, the turbine (steam) exhaust is converted into a huge amount of (sea water) cooling water, which is discharged into the sea and has a significant impact on the marine environment. there is. This steam has (condensation) heat of condensation of 563kcal/kg at 0.2bar 60℃, and water absorbs 1kcal/kg of heat when the temperature rises by 1℃, The temperature rises by 1 degree Celsius. As such, steam is not easily recovered due to the enormous heat of condensation. However, in the present invention, in the exhaust cooler, (80 + 20) 100 mol% exhaust from the combustion chamber with only 40% of the liquid (-183 ° C) refrigerant (20 mol% x 130%) oxygen as the refrigerant with the preceding exhaust-condensation is cooled, vapor condensed, and 10 mol% CO ₂ is collected by cooling to -13°C. That is, for pure oxygen combustion, 100 mol% vapor in the exhaust of this combustion chamber is cooled only by the amount of heat (340 kcal) in which the liquid refrigerant -183°C 40% oxygen among the oxygen (20 mol% x 130%) supplied to the combustion chamber is preheated to 50°C. condensate, and 10 mol% CO ₂ is collected by cooling to -13 °C. As such, the reason why steam with the characteristics of enormous condensation heat is cooled is that (ki-plural) gat condensate utilizes the enormous heat of evaporation as cooling heat as a refrigerant, cools (steam) exhaust, absorbs enormous condensation heat, and This is because it evaporates into steam at °C and cools the combustion chamber (inlet) exhaust. For example, put (1+0.1) 1.1atm 100g 110℃ steam in one balloon bag, put saturated water at 1atm 100g 100℃ saturation temperature in another balloon bag, and keep all of these balloon bags warm. If you put it in a container for a while, all of this 110℃ steam will be converted to 100℃, and all of this 100℃ saturated water will evaporate into steam. As such, according to the principle of thermodynamics, the 110°C inflow exhaust is cooled and condensed, and the 60°C circulating water absorbs the exhaust heat (condensation heat) of the combustion chamber inflow and exhaust with enormous evaporation heat and evaporates into 90°C steam. The enormous (condensation heat) exhaust heat absorbed by the gas and condensate is entirely recovered by means of a heat pump. In summary, this enormous exhaust heat is (temporarily) transferred to composite recycle nitrogen (explained next), and this vapor is condensed to the operating pressure of the combustion chamber to (temporarily) retaining the combustion chamber exhaust heat, to the composite recycle nitrogen, 270 ° C) is preheated, and all of the exhaust heat from the combustion chamber is recovered. This exhaust heat recovery process is described in detail below.

In the present invention, exhaust from the boiler combustion chamber is introduced (intake) to the exhaust cooler at a back _{pressure of 0.2 bar, and is circulated in the exhaust heat absorber absorber, vapor cooler cooler, and CO 2 cooler} . Steam and product steam are cooled with gas-condensation (of the preceding exhaust) and a small amount of refrigerant oxygen, so that the steam in the exhaust is condensed and the exhaust 10 mol% CO ₂ is captured at -13°C. In this exhaust heat absorber, the gas-condensate in the saturation temperature state of back pressure 0.2 bar cools the inlet exhaust of the combustion chamber (suction) with enormous evaporation heat, absorbs the enormous (convergent) condensation heat and raises the temperature to 90 ° C steam, and this combustion chamber exhaust is , in the Vapor Cooler cooler, it is further cooled by the refrigerant oxygen flowing through the tube, the vapor in the exhaust is condensed, and the remaining CO ₂ , unburned oxygen, etc. are further cooled by the refrigerant oxygen in the CO ₂ cooler on the far right , CO ₂ is cooled to -13°C and discharged (captured) by the vacuum pump, and the excess supplied unburned oxygen and non-condensable gases such as CO ₂ are sucked into the cold air circulation pipe (described below) and returned to the front. This liquid phase is preheated to 50 °C by the refrigerant oxygen. Fresh condensate is transferred to the exhaust heat absorber tube by a condensate pump in a hot well, and, as described above, cools the inflow exhaust from the subsequent combustion chamber, raises the temperature to 90 ° C. steam, and is sucked and discharged by the vacuum pump. In the CO ₂ cooler, liquid refrigerant oxygen is injected into its tube and then supplied to the steam cooler. The structure of this exhaust cooler and the process of cooling and condensing the exhaust will be described in detail next.

FIG. 3 (FIG. 2) is a diagram showing the shape of a main part of a cold gas circulation blade for collecting and discharging non-condensable gases, such as excess oxygen and carbon monoxide (CO) generated by incomplete combustion, in this exhaust cooler. . Since non-condensable gases, such as unburnt oxygen and carbon monoxide generated by incomplete combustion, exist in the combustion chamber exhaust, these non-condensable gases must be removed. As shown in FIG. 3, as the blade rotates, these non-condensable gases, together with a small amount of CO ₂ , are sucked in from the ceiling of the cooler chamber of the CO ₂ Cooler and circulated toward the center front, and non-condensable gases lighter than CO ₂ such as oxygen and CO captured and released 4 and 5 are diagrams related to a process in which exhaust heat from the combustion chamber is recovered, which will be described next. 6 is a view showing the main part of a power generator for recovering exhaust heat from the combustion chamber, and FIG. 7 is a view showing the shape of commercial lobe pumps having a structure similar to this power generator. As shown in FIG. 1, this power generator is installed at the rear end of the outlet where the combustion chamber exhaust is discharged, so that the combustion chamber is in a sealed state, a constant pressure of 1 atm or more is maintained, and the combustion chamber exhaust is discharged, and the combustion chamber exhaust is discharged through the power generator. Through this, exhaust is discharged to the present exhaust cooler, and a bypass passage is installed from the front to the back of the power generator so that the pressure at the rear end of the power generator can be controlled. With this means, the combustion chamber exhaust is discharged through this power generator, rotating the power generator (lobe) rotor at the pressure of the combustion chamber, and is discharged while producing power.

Through the bypass passage through the power generator and the diffuser (FIG. 2), combustion chamber exhaust flowing into the exhaust cooler can be maintained at a back pressure of 0.2 bar and 110°C. In this exhaust cooler, since the circulating steam and the generated (80+20) 100 mol% steam are condensed, the steam volume is usually reduced by 1/1650 times, so the combustion chamber exhaust is sucked into this exhaust cooler, as in the steam turbine condenser, and the combustion chamber operates The pressure can be maintained at the back pressure of 0.2 bar by controlling the flow rate through the power generator and the bypass passage, and the exhaust temperature flowing into the exhaust cooler is controlled through the diffuser bypass passage and maintained at 110 ° C. do. For example, steam has an adiabatic index value of k = 1.327, so when 1atm 300℃ steam adiabatically expands to 0.2bar, the temperature of the steam drops to 110℃. Therefore, in this exhaust cooler (Fig. 2), the combustion chamber exhaust is sucked in through this power generator at a back pressure of 0.2 bar and a temperature of 110° C. The exhaust gas from the combustion chamber is cooled and condensed by the heat of evaporation. In fact, effective power cannot be obtained from this power generator, but the combustion chamber exhaust (suction) flows into this exhaust cooler at a back pressure of 0.2 bar, so that the combustion chamber exhaust (80+20) 100 mol% steam is cooled and condensed, and its enormous exhaust heat is all The effect of recovery is truly enormous.

The power generator has the same structure as the Lobe pump shown in FIG. 7, which transfers general liquid, and has a diffuser nozzle-shaped pressure reducing nozzle attached to the pump inlet. With this pressure reducing nozzle, the combustion chamber exhaust is resisted, so the combustion chamber pressure is kept higher, and the exhaust with pressure expands in this power generator to produce some power. As shown in FIG. 7, the pressure of the exhaust in the pocket by the lobe of the rotor is discharged without being converted into power, so that all of the pressure energy of the gas in this power generator is not converted into mechanical power, but the pressure reduction nozzle As a result, losses are minimized. In other words, the pressure energy (PV) of this working fluid is converted into kinetic energy (1/2mv^2) as it passes through this diffuser nozzle, and as in a turbine, the effect of the fluid particles running at high speed colliding with the rotor lobe is More power is produced with the impulse (Δmv) of the generated and exhausted particles, minimizing heat loss.

In the present invention, the boiler combustion chamber exhaust passes through the power generator described above, the pressure drops to a back pressure of 0.2 bar and a temperature of 110 ° C, and is introduced (suction) to the exhaust cooler, and as described above, it is cooled and condensed, and group-plural. The temperature is raised with 90°C steam, pressurized to 1 atm or more by means of a heat pump, and cooled. Of this 1 atm condensate, 20 mol% product steam is utilized for carbon neutrality (described below), and 80 mol% circulating steam is recycled to the combustion chamber. That is, circulating steam continues to circulate with this 80 mol% working fluid. Therefore, since a small amount of environmental pollutants may melt (accumulate) and exist in this circulating steam, (Fig. circulated water is supplied to this hot well.

In the present invention, for pure oxygen combustion, nitrogen is produced in a liquid phase along with oxygen from compressed air and used as a refrigerant, and 40% of this 20 mol% x 130% oxygen is, as described above, (FIG. 2) In this exhaust cooler, the combustion chamber exhaust is cooled, preheated to 50 ° C, and CO ₂ captured at 0.2 bar -13 ° C for carbon neutrality with 10% oxygen among the remaining 60% oxygen, (FIG. 1) outside ( CO ₂ ExCooler) In the CO ₂ cooler, it cools down to 5℃ at 1atm and raises the temperature to 80℃. In more detail, 0.2bar -13℃ CO ₂ is pressurized at 1atm with a vacuum pump and the temperature is raised to 100℃, and then the liquid refrigerant 20mol% x 130% oxygen 10%, in an external CO ₂ cooler, to 5℃ Cooled down, this oxygen is heated to 80 °C. The remaining 50% liquid -183 ° C oxygen is mixed with 50 ° C 40% oxygen and 80 ° C 10% oxygen at -179 ° C, and preheated to a high temperature in an oxygen preheater (described next) shown in FIG. injected into the combustion chamber.

In the distillation tower where oxygen and nitrogen are produced separately, compressed air heated to 210℃ by compressing the atmosphere to 5.5 kg/cm ² is recycled and cooled with 30 mol% nitrogen as a liquid refrigerant in the compressed air cooler (Compressed Air Cooler) cooler. , Compressed air that meets the distillation column operation condition (5.5kg/cm ² 77°C) is supplied to the distillation column, as shown in FIG. % Nitrogen cools compressed air at 210°C under distillation column operating conditions and raises the temperature to 190°C. This 190°C nitrogen heats (Boost up) 90°C circulating steam that has absorbed the exhaust heat to 120°C by means of a heat pump in the combustion chamber exhaust heat recovery system (FIG. 5) described below. The operating conditions of the distillation tower refer to the patented 'nitrogen gas production system' invented by POSCO. Of the 104 mol% liquid nitrogen produced along with oxygen in this oxygen and nitrogen production system (80 mol% x 130%), the remaining nitrogen except for 40 mol% nitrogen, which is 30 mol% nitrogen plus 10 mol% nitrogen used for cooling this compressed air, is It is not produced in liquid form at all, or used for other purposes.

The coal boiler has an economizer, and in this economizer, the feed water supplied to the combustion chamber of the boiler is preheated. The exhaust of this economizer is usually hot, over 350°C. Even in gas boilers, exhaust from the combustion chamber is predicted to be 350 ° C or more, and with this combustion chamber exhaust, as shown, in the circulating steam (Circ.Stm PreHte # 3) preheater # 3 and oxygen (Oxygen PreHtr) preheater, (next described above) is preheated to a higher temperature and injected into the combustion chamber and recirculated, and the oxygen is preheated to a higher temperature and supplied to the combustion chamber.

Exhaust from the combustion chamber of the boiler, as shown in FIG. 1, passes through the circulating steam preheater #3 and the oxygen preheater, and then mostly passes through the power generator and is sucked into the exhaust cooler at 110°C. A small amount of exhaust does not pass through this power generator, but flows directly to the rear end of this power generator through a bypass passage with a diffuser (Diffuser). As the combustion chamber exhaust expands through a flow control valve that controls the flow rate of the bypass passage, the pressure and temperature drop significantly. By means of this power generator and bypass passage, (Fig. 2) the temperature of this exhaust air drawn into this exhaust cooler is maintained at 0.2 bar 110°C.

In order to be carbon (CO ₂ Net Zero) neutral, pure oxy-combustion must be implemented and CO ₂ must be captured, and therefore, for this pure oxy-combustion, steam is circulated as a working fluid into the combustion chamber in a gas turbine, or CO ₂ should cycle. In the gas turbine oxy-combustion CES cycle, circulating steam is recirculated into the combustion chamber, and in the Allam cycle, CO ₂ is recirculated into the combustion chamber, thereby preventing overheating of the combustion chamber and improving power production efficiency in the turbine. In the present invention, as in the CES cycle, circulating steam is recirculated into the combustion chamber to prevent overheating of the combustion chamber, and furthermore, even without seawater being used as cooling water, this combustion chamber exhaust is multiplied, and its exhaust heat is recovered in its entirety, so that the heat pump means , subtracting the compressor driving power, 77% of net heat compared to this exhaust heat is recovered.

In the present invention, 0.2bar -13℃ CO ₂ collected in this exhaust cooler is heated by 100℃ at 1atm with a vacuum pump by pure oxy-combustion to realize carbon neutrality, and then dissolved well in water, (FIG. 1) In an external (CO ₂ ExCooler) CO ₂ cooler, a small amount of refrigerant (20 mol% x 130%) 10% oxygen, cooled to 5° C., and 20 mol% product steam, described next ( FIG. 5 ), condensate (Condensate Cooler) ) In a cooler, it is cooled with 5℃ cooling water, and in this cooling water (H ₂ O+CO ₂ Mixer) mixer, the CO ₂ is dissolved in carbonated water. Although this CO ₂ is known to be well soluble in seawater, it is expected that a catalyst soluble in water will be developed in the course of realizing the present invention in the future. This carbonated water (recently developed technology) is supplied to a system that produces hydrogen with CO ₂ to produce clean energy hydrogen. ₃ ) is produced, and this hydrogen, 1.5 times more than liquid, is stored in NH ₃ at room temperature and low pressure (8.6 bar). Since ultra-high pressure is required to store this hydrogen as a liquid, this hydrogen storage means, for example, magnesium-nickel alloy, titanium-manganese alloy, _etc. Hydrogen storage alloys, in which is stored, have been studied. However, in ammonia, which is mainly used as a raw material for fertilizer, this hydrogen has already been liquefied and stored at low pressure at room temperature, 1.5 times more than liquid, so this ammonia has recently attracted attention as a means of storing and transporting hydrogen. In addition, a new technology for producing this HN ₃ at a low pressure and low temperature of 1 atm and 45 ° C has recently been developed, and a catalyst and membrane for separating ammonia into hydrogen and nitrogen have been recently developed at the Center for Hydrogen Fuel Cell Research at the Korea Advanced Institute of Science and Technology (KIST). . In other words, this KIST technology means that hydrogen can be easily extracted and used from ammonia. This era of clean energy hydrogen economy is expected to be realized in the near future. In the present invention, this CO ₂ constantly generated by combustion is not released into the atmosphere, but is captured by pure oxygen combustion, and hydrogen is produced from this CO ₂ , and this hydrogen is produced from nitrogen used as a refrigerant to produce ammonia. , Eventually, clean energy hydrogen is stored in ammonia, and carbon (CO ₂ Net Zero) neutrality is realized.

4 is a flow diagram of a system for liquefying nitrogen to use nitrogen already used as a refrigerant as a refrigerant. In the present invention, 20 mol% x 130% more oxygen supplied to the combustion chamber is produced and supplied to the combustion chamber than the theoretical supply amount of combustion, so nitrogen is also produced (80 mol% x 130%) 104 mol% more. However, in the combustion chamber exhaust heat recovery system (FIG. 5), 48 mol% liquid nitrogen is required as a heat pump means, 30 mol% liquid nitrogen is required for compressed air cooling, and a total of 78 mol% liquid nitrogen is required. 38 mol% nitrogen preheats the circulating water in the nitrogen liquefaction cooling system (FIG. 4) and must be cooled in liquid phase, so the remaining nitrogen except for 40 mol% nitrogen out of 104 mol% produced with oxygen can be used for other purposes or used in liquid phase. do not produce at all. In the nitrogen liquefaction cooling system described below (FIG. 4), 38 mol% nitrogen is cooled to 120° C. while preheating circulating water (steam), which is recycled to the combustion chamber, to 620° C., cooled to liquid phase, liquefied, and liquid phase. of refrigerant is supplied.

Russian (Kapitza) Kapitza, who received the 1978 Nobel Prize in Physics in the field of cryogenic physics, is a method of cooling and liquefying air. The air liquefaction efficiency was greatly improved by replacing the expander with the expander, and this air liquefaction method is still widely used today. In the present invention, this method of liquefying air is utilized, and after nitrogen already used as a refrigerant is stored, it is cooled and liquefied again to be used as a refrigerant. Below is a description of this nitrogen liquefaction cooling process.

As shown in FIG. 4, the stored 1 atm pressure 120°C nitrogen is compressed at 20 bar and the temperature is raised to 650°C, and in the circulating water (CircWtr PreHtr#2) preheater #2, the circulating water (CircWtr) is preheated to 620°C, 650°C nitrogen is first cooled to 120°C. Subsequently, the 20 bar 120 ° C nitrogen is further compressed to (Δ10 bar) 30 bar, the temperature raised to 160 ° C, and further cooled in the secondary (2ndN ₂ Cooler) cooler. This 1 atm nitrogen is originally compressed to 30 bar in the Kapitsa cooling system and cooled (cooled) in the secondary cooler, but in the present invention, it is compressed to 20 bar in the primary compressor and further compressed to 30 bar in the secondary compressor. Circulating water (CircWtr PreHtr#2) In preheater #2, 100°C (80mol% x 14%) circulating water (described next) is preheated to 620°C with 20bar (38+2) 42mol% 650°C nitrogen, This 650°C nitrogen is cooled (cooled) to 120°C. Of this cooled 20 bar 120°C 42 mol% nitrogen, 4 mol% nitrogen is stored in a low-temperature nitrogen storage tank after adiabatic expansion at 1 atm through an expansion valve and a temperature drop to -100 °C. In addition, the flow rate of 1 atm low-temperature nitrogen recirculated to the compressor is controlled, as shown in the figure, so that 1 atm 42 mol% nitrogen is not compressed to a set temperature of 650 ° C or less in the compressor, and nitrogen in the high-temperature nitrogen storage tank and 120 ° C is mixed into and injected into the compressor, and the rest is stored in a low-temperature nitrogen storage tank. After cooling to 120 ° C in the primary cooler and raising the temperature to 160 ° C under pressure at 30 bar, this compressed nitrogen is further cooled with (preceding) 1 atm (expansion) low-temperature nitrogen in the secondary cooler, followed by 80% flow rate of this cooling nitrogen. As it is gradually adiabatically expanded by this rotary vacuum pump (not the inverse turbine expander of Kapicha), the temperature of this nitrogen is greatly reduced. With this low-temperature nitrogen, the remaining 20% of nitrogen is cooled and liquefied as it flows from the nitrogen (N ₂ Condenser) condenser to the tube. This liquid nitrogen moves to the liquid nitrogen cooler, flows through the tube and is further cooled, and this 30 bar liquid nitrogen is pumped to the evaporator vessel, passes through the expansion valve, and expands to 1 atm by the vacuum pump, resulting in the Joule-Thomson effect. As a result, the nitrogen temperature (saturation temperature -195.79 ° C) is reduced to -196 ° C, some of this expanded nitrogen is liquefied at -196 ° C, and the rest is vaporized. This gaseous nitrogen, whose temperature has dropped significantly, is mixed with nitrogen discharged from the nitrogen condenser after cooling the subsequent 30 bar liquid nitrogen flowing into the tube in the liquid nitrogen (Liq.N ₂ Cooler) cooler, and then in the secondary cooler At , the subsequent 30 bar nitrogen is cooled and sucked into the vacuum pump, and most of this nitrogen is stored in a low-temperature nitrogen storage tank, and some is injected and recycled to the compressor. The nitrogen liquefied at 1 atm in the evaporator vessel is supplied by a low pressure pump to the outlet pipe of the liquid refrigerant nitrogen supply pump shown in FIG. 1 . In the above description, the reason why 4 mol% of the nitrogen cooled to 120 ° C after being compressed at 20 bar bypassed the secondary cooler is that in normal operation, the circulating water at 100 ° C is preheated to 620 ° C, and liquid nitrogen This is because only 38 mol% nitrogen needs to be cooled to the liquid phase to avoid overproduction. This is used as a means of controlling the production of liquid refrigerant nitrogen according to the load in the combustion chamber.

In the nitrogen liquefaction cooling system, the pressure at which nitrogen is compressed is compressed to a pressure lower than 30 bar in the realization stage of the present invention. Through trial and error, this economical nitrogen compression pressure is set so that this nitrogen is compressed to a pressure as low as possible, thereby reducing the compressor drive power and liquefying into the liquid phase. 78 mol% 120° C. nitrogen of the 628 mol% nitrogen for composite recycle (FIG. 5) described below is returned to the nitrogen storage tank, of which 38 mol% nitrogen, (FIG. 4) in the nitrogen liquefaction cooling system, must be liquefied. Therefore, for example, when the 120° C. nitrogen is compressed to 20 bar, the temperature rises to 650° C., so the circulating water can be preheated to 620° C. with this compressed nitrogen, and the compressor driving power is also required much less. For this reason, in the present invention, (preceding) the low-temperature nitrogen expanded to 1 atm is immediately re-entered into the compressor, so that the compressed nitrogen temperature does not fall below 650 ° C., as shown, stored in a low-temperature storage tank. configured so that In the secondary compressor, 120 ° C nitrogen is set to 30 bar 160 ° C, this nitrogen compression pressure is set to a lower pressure through trial and error in the present invention realization stage.

As shown in FIG. 4, the compressed nitrogen expander of the nitrogen liquefaction cooling system and the (CO ₂ Cooler) CO ₂ cooler in the present exhaust cooler (FIG. 2) are equipped with a special rotary piston vacuum pump. This vacuum pump is a 'rotary piston gas transfer (suction/compression) pump' that has not yet been commercialized but has been patented (10-24115730000, 2022-06-16). and rotates, and the disk is blocking the piston, but the piston and the disk are cycloid curves of pin gears (used for teeth of clocks, gauges, etc.), so they rotate without colliding with each other. It is configured in the form of a helical gear (with only one tooth) so that while the piston rotates, the working fluid is sucked in from the back of the piston and compressed and discharged from the front of the piston. These rotary piston vacuum pumps pump the working fluid (like a piston pump but continuously like a centrifugal pump).

Steam has more heat of condensation than any other gas (539kcal/kg based on 1atm), so in a boiler where steam circulates as a working fluid, seawater is not used as a cooling water, and the combustion chamber exhaust is (8H ₂ O + 2O ₂ + CH ₄ = 8H ₂ O + CO ₂ + 2H ₂ O), it is impossible to obtain condensation by means of ordinary heat exchangers, and besides, the method of recovering this (steam) exhaust heat with circulating water of the working fluid is not easy by means of ordinary heat pumps. In all power plant steam turbines around the world, the exhaust from the combustion chamber is converted to (seawater) cooling water, and the fact that 50% of the exhaust heat applied to the steam is released to the sea proves this. However, in the present invention, as follows, the enormous evaporation heat is utilized as cooling heat, the combustion chamber exhaust is cooled, and steam is condensed, and this enormous combustion chamber exhaust heat is recovered in its entirety by the heat pump technology as follows , subtracting the compressor driving power, 78% net heat is recovered compared to the exhaust heat. This exhaust heat recovery process is described below.

FIG. 5 shows that in the exhaust heat absorber in the exhaust cooler (FIG. 2), the exhaust heat of the combustion chamber is cooled by the enormous evaporation heat, the exhaust heat is absorbed, and after the temperature is raised to 90° C., the heat pump means, the exhaust heat of the combustion chamber This is a flow diagram showing the recovery process. The exhaust from the combustion chamber (intake) flows into the exhaust cooler (FIG. 2), and is cooled in an exhaust heat absorber at the inlet (Exhaust Heat Absorber) at a saturation temperature of 0.2 bar (group-condensate). That is, as this gas-condensate evaporates into steam, the inlet exhaust is cooled and condensed due to the enormous evaporation heat, and the temperature of this steam is raised to 90°C. This 90°C steam is pumped to the combustion chamber exhaust heat recovery system (FIG. 5), in a steam (StmHtr) heater, by means of a heat pump, to 120°C (boost up) with 133°C 163 mol% recycle nitrogen (described below). It is heated, pressurized to 1 atm, heated to 310°C, and (StmCond) pumped to a condenser. The 90℃ steam is heated to 120℃ and the 133℃ recycle nitrogen is cooled to 110℃ and injected as a refrigerant into the condenser. In this condenser, the 310°C 1atm (20+80) 100 mol% steam is cooled to 87°C and 628 mol% composite recycle nitrogen condensed to 100°C, and the composite recycle nitrogen is heated to 295°C. This composite recycle nitrogen is as follows, 163 mol% 110°C nitrogen above, 120°C 417 mol% recycle nitrogen injected as refrigerant directly to the condenser in circulating water (CircWtr PreHtr#1) preheater #1 (described next), It is recycled nitrogen that is a mixture of 85°C 11 mol% nitrogen and liquid -196°C 37 mol% nitrogen cooled to 5°C in a condensate cooler from 20 mol% steam generated by combustion at 87°C. This composite recycle nitrogen condenses the 310 ° C steam to 100 ° C and raises the temperature to 295 ° C, and is converted into a heat transfer medium holding a huge amount of exhaust heat absorbed by the steam and condensate, and the exhaust heat is completely recovered as follows.

In the condenser, in the 1 atm 100 ° C condensate, the 20 mol% condensate produced by combustion moves to the condensate (Condensate Cooler) cooler and is cooled to 5 ° C with 11 mol% nitrogen as a liquid refrigerant, and as shown, this cooling water is a low-pressure (LP) pump, and for carbon neutrality, 10 mol% CO ₂ produced by combustion is dissolved in carbonated water in cooling water, (H ₂ O+CO ₂ ) is transferred to a mixer (Mixer). The remaining 80 mol% (plural) circulating water is pressurized to the operating pressure of the combustion chamber. At the current stage of the invention, the operating pressure of the combustion chamber is 1 atm, but when the operating pressure of the combustion chamber is higher, more exhaust heat is recovered. Of this circulating water, 14% of the circulating water is pumped to the circulating water preheater #2 (described above) (Fig. 4) by the condensate pump, and most of the circulating water (80mol%x86%) is (CircWtr PreHtr#1) circulating water It is pressurized to preheater #1 and is preheated to 280°C with 295°C 628 mol composite recycle nitrogen having the exhaust heat, and the nitrogen is cooled to 120°C. 87 mol% nitrogen of this 120 ℃ complex recycle 628 mol nitrogen is stored in the nitrogen storage tank, 417 mol% nitrogen of the remaining 550 mol% nitrogen is directly injected and recycled as a refrigerant to the (StmCond) condenser, and the remaining 120 ℃ (550-417) 133 mol% nitrogen was mixed with 30 mol% nitrogen at 190°C and 163 mol% 133°C in the compressed air cooler described above, and as described above, in a steam (StmHtr) heater, by means of a heat pump, the 90°C steam was heated to 120°C. After heating to 110° C., the (StmCond) condenser is injected as a refrigerant and recycled. In this way, this composite recycle nitrogen injected into the condenser cools and condenses 310 ° C (20 + 80) 100 mol% steam as a refrigerant, raises the temperature to 295 ° C as a heat transfer medium, and recovers all exhaust heat from the combustion chamber. The remaining (100-86) 80 mol% x 14% circulating water among the (plural) circulating water is circulating water of the nitrogen liquefaction cooling system (CircWtr PreHtr#2) in the preheater #2 (FIG. 4), as described above, at 20 bar With 650 ° C nitrogen, it is preheated to 620 ° C, and 20 bar 620 ° C nitrogen is cooled to 120 ° C so that (78-40) 38 mol% nitrogen required in this (Fig. 5) exhaust heat recovery system is cooled and liquefied.

The following describes a process in which the combustion chamber exhaust is cooled and the exhaust heat is recovered in the present invention from a thermodynamic point of view. As shown in FIG. 2, the combustion chamber (inflow) exhaust drawn into the exhaust cooler at 110° C. and a back pressure of 0.2 bar is (8H ₂ O + 2O ₂ + CH ₄ = 8H ₂ O + CO ₂ + 2H ₂ O) at the inlet 80 mol% 0.2bar 60℃ (0.2bar saturation temperature 60.06℃) (saturation temperature 60.06℃), flowing into the exhaust heat absorber tube, is freshly cooled as condensate, and this condensate evaporates into 90℃ steam. 10 mol% CO ₂ of this inlet exhaust is cooled and discharged at -13℃ in the CO ₂ cooler. In this cooling process, the sum of the heat amount by which (20+80) 100 mol% steam is cooled from 110°C to 90°C in the inlet and exhaust and the heat amount by which the inlet and exhaust 110°C CO ₂ is cooled to -13°C is -186°C. The liquid phase is in thermal equilibrium with the amount of heat preheated to 50℃ by refrigerant 20mol% x 130% oxygen 40%. That is, since the amount of heat converted from 90℃ steam to 60℃ and the amount of heat evaporated from 60℃ steam-condensate to 90℃ steam during the inflow and exhaust of the combustion chamber are the same, 100 mol% 110℃ steam has a small amount (40%) of liquid refrigerant oxygen. It is cooled and condensed only with the amount of heat preheated to 50℃.

In a compressed air cooler for producing oxygen and nitrogen, 130 mol% 210°C compressed air is cooled to 77°C with liquid 30 mol% -196°C refrigerant nitrogen, and this nitrogen is heated to 190°C in thermal equilibrium. Then, this 30 mol% nitrogen was mixed with 133 mol% nitrogen in 120 ° C composite recycle nitrogen at 163 mol% 133 ° C in the steam (StmHtr) heater of the exhaust heat recovery system (Fig. 5), (20 + 80) 100 mol% 90 ° C The 0.2 bar steam is heated (boost up) to 120°C and cooled to 110°C to achieve thermal equilibrium. This 0.2 bar 120℃ 100 mol% steam is pressurized at 1 atm, heated to 310℃, cooled with 87℃ 628moo% composite recycle nitrogen, condensed to 100℃, and this composite recycle nitrogen is heated to 295℃ to achieve thermal equilibrium. . The 20 mol% portion produced by combustion of this 100 ° C (condensate) 628 mol% condensate is cooled in a condenser cooler with liquid refrigerant -196 ° C 11 mol% nitrogen and 5 ° C cooling water, and this nitrogen is heated to 85 ° C, achieve thermal equilibrium. Most (86%) of the remaining 80 mol% circulating water is preheated to 280°C with the 297°C 628 mol% complex recycle nitrogen in the circulating water preheater #1, and the 295°C nitrogen is heated to 120°C in thermal equilibrium. cooled and recycled. The remaining (100-86) 80mol% x 14% 100℃ circulating water is, (FIG. 4) circulating water of nitrogen liquefaction cooling system (CircWtr PreHtr#2) in preheater #2, (38+4) 42mol% 650℃ 20bar nitrogen It is preheated to 620 ℃, and this 20 bar nitrogen is cooled to 120 ℃ to achieve thermal equilibrium.

Below, the exhaust that has flowed (intake) into the exhaust cooler seen from the combustion chamber is cooled by a plurality of groups and pressurized to 1 atm by means of a heat pump (FIG. 5), and the amount of heat recovered by this 80 mol circulating water (steam) is This is an explanation of exhaust heat and comparison. When pressure is applied to a gas in a cylinder, (enthalpy) enthalpy (PV) increases, and when the piston moves backward, this enthalpy decreases, and the enthalpy decrease is converted into mechanical power. More specifically, when a gas is compressed with a piston, the kinetic energy of the gas particles increases as the enthalpy due to the increase in PV increases, so the temperature rises and the internal energy (U) of the gas also increases. do. That is, the enthalpy of a gas is given by H = PV + U. Therefore, the power applied to this gas is given by Δh = h2 - h1, the enthalpy difference before compression (h1) and after (h2), and the amount of heat lost or recovered is also given by Δh = h2 - h1, enthalpy difference. (FIG. 5) In the steam compressor, 0.2 bar 80 mol% 120 ° C steam pressurized at 1 atm and heated to 310 ° C, 0.2 bar 120 ° C h1 = 2,724.60 kJ / kg, 1 atm 310 ° C h2 = 3,094.70 kJ / kg, Δh = 3,094.70 - 2,724.60 = 370.1 kJ/kg, where the flow rate is applied, the compressor driving power is calculated as Pwr = 370.1 x 18 x 80 mol% = 6,662 kJ. (FIG. 4) In the primary nitrogen compressor of the nitrogen liquefaction cooling system, (38+4) 42 mol% 1 atm 120 ° C nitrogen is compressed to 20 bar 650 ° C, 1 atm 120 ° C h1 = 408.11 kJ / kg, 20 bar 650 ° C h2 = 987.78 kJ/kg, Δh =579.67 kJ/kg, Pwr = 579.67 x 28 x 42 mol% = 6,817 kJ power is required. Next, in the secondary compressor, 38 mol% 120 ° C nitrogen is compressed to 30 bar, so 20 bar 120 ° C h1 = 406.04 kJ / kg, 30 bar 160 ° C h2 = 447.74 kJ / kg, Δh = 41.7 kJ / kg, Pwr = 41.7 x 28 x 380 mol% = 444 kJ power is used, so the total driving power of the compressor adds up to (6,662 + 6,817 + 444 ) 13,923 kJ.

The 20 mol% CO ₂ produced by combustion among the combustion chamber exhaust cannot be regarded as an exhaust loss, so its exhaust heat amount is ignored, and only the heat amount exhausted as a multiple of 80 mol% circulating steam circulated as a working fluid at 110℃ to 60℃ is considered an exhaust loss. Looking at it, 0.2 bar 110 ℃ h1 = 2,705.40 kJ/kg, 0.2 bar multiple h2 = 251.18 kJ/kg, Δh = -2,454.22 kJ/kg, exhaust heat is calculated as -2,454.22 x 18 x 80 mol% = -35,341 kJ. 80 mol% circulating water corresponding to this (steam) exhaust was evaporated at 0.2 bar 90 ° C in this exhaust cooler, and then condensed at 1 atm 100 ° C in the (StmCond) condenser by means of a heat pump, so 0.2 bar 60 ° C circulation Number h1 = 251.18 kJ/kg, 1 atm 100°C multiple h2 = 417.5 kJ.kg, Δh = 166.32 kJ/kg, RcvH1 = 166.32 x 18 x 80 mol% = 2,395 kJ heat is recovered. Next, in the circulating water preheater #1, since this (plural) circulating water 100°C 80 mol% x 86% circulating water is preheated to 1atm 280°C, 1atm 100°C h1 = 417.50 kJ/kg, 1atm 280°C h2 = 3034.40 kJ/kg , Δh = 2,616.9 kJ/kg, RcvH2 = 2,616.90 x 18 x 80 mol% x 86% = 32,408 kJ heat is recovered. Next, 1atm 100℃ remaining 14% circulating water (FIG. 4) is preheated to 1atm 620℃ in circulating water preheater #2, so 1atm 100℃ h1 = 417.50 kJ/kg, 1atm 620℃ h2 = 3749.80 kJ/kg, Δh = 3,332.3 kJ/kg, RcvH3 = 3,332.3 x 18 x 80 mol% x 14% = 6,718 kJ heat recovered, adding up the total heat recovered to (2,395 + 32,408 + 6,718) 41,521 kJ. If the driving power is subtracted from this recovered heat amount, (Net) net (41,521-13,923) 27,598 kJ heat is recovered, which is 78% of (Net) net heat (27,598 / 35,341) heat recovery. As such, the reason why a large amount of heat is recovered is that steam has a characteristic of an enormous heat of vaporization (Latent Heat). For example, CO ₂ has a heat of evaporation of (282.44 kJ/kg) 67.46 kcal/kg at 20 bar -20°C and steam has a heat of evaporation of 539 kcal/kg at atmospheric pressure. If steam does not have the characteristics of enormous heat of vaporization like this CO ₂ , in the present invention, by means of a heat pump, exhaust heat is not recovered much. That is, it is because the power obtained is not so great as the driving power of the compressor.

Below, the structure of this exhaust cooler, shown in FIG. 2, will be explained in detail. This exhaust cooler is composed of (Air Fin) air fin cooler type (Shell & Tube) shell-tube heat exchanger. At the inlet where the combustion chamber exhaust (intake) flows in, an exhaust heat absorber is installed, which cools the combustion chamber (intake) inflow exhaust with enormous evaporation heat and absorbs the exhaust heat, followed by an exhaust mini cooler. Next, there are a number of cold air circulation pipes that emit cold air from the ceiling of the chamber, then a number of water spray nozzles that emit water vapor spray from the ceiling, and then, refrigerant oxygen A vapor (Vapor Cooler) cooler is installed that cools the incoming exhaust as it flows through the tube and finally condenses the steam, and a CO ₂ cooler (CO ₂ Cooler) that supplies liquid refrigerant oxygen to the tube is installed on the far right. , and a plurality of cold air circulation pipes are installed in the far right ceiling of the CO ₂ cooler chamber, through which cold gases are sucked in and blown out from the ceiling on the right side of the exhaust mini cooler. Non-condensable gases such as oxygen, CO, N ₂ and a small amount of CO ₂ are inhaled and circulated. At the T-junction above the inlet of the cold air circulation pipe, a cold air circulation (Blade) blade shown in FIG. The space is equipped with a sensor that detects this non-condensable gas. The structural function of this exhaust cooler will be described in detail below.

In the present invention, 130% more oxygen is supplied to the combustion chamber than the theoretical supply amount. Therefore, (20mol% x (130%-100%)) 6mol% traces of unburnt oxygen, carbon monoxide (CO) generated from incomplete combustion, and ultra-trace nitrogen, which are excessively supplied to the combustion chamber, are collected and removed, In addition, through the exhaust mini cooler, the inlet exhaust is somewhat cooled by its cooling heat. When the cold air circulation blade rotates, non-condensable gas and a small amount of CO ₂ are sucked in, and the heavy (large mass) CO ₂ flows by centrifugal force to the circulation pipe outside the circumference of the blade, and the CO ₂ escapes (empty) Filling the space with light non-condensable gas, it rises upward and rises to the non-condensable gas collection space. This non-condensable gas is mostly composed of a trace amount of oxygen (6 mol%) that is oversupplied to the combustion chamber. As the circulation blade rotates, this collected non-condensable gas is sucked into the vacuum pump as shown in the figure, and is forced to the exhaust mini-cooler, cools the intake exhaust air somewhat, and is discharged to the atmosphere. The cold air from the CO ₂ cooler chamber is sucked into this cold air circulation pipe and blown out from the upper ceiling, effectively cooling the incoming exhaust. In addition, so that this exhaust is more effectively cooled, after the cold air outlet of this cold air circulation pipe, (preceding exhaust) steam is cooled and condensed, and water vapor spray is ejected from the ceiling through a plurality of water spray nozzles, so that the inflow exhaust is It is directly cooled by this water vapor spray and becomes condensate, then further cooled in a vapor cooler, and finally vapor becomes condensate. Under this steam cooler, (Hot Well) fresh condensate collected in the hot well is transferred to the tube of the exhaust heat absorber, and in this exhaust heat absorber, the inflowing exhaust is cooled with enormous heat of evaporation, and the enormous (condensed) condensation heat After absorbing and raising the temperature to 90℃ steam, it is suctioned and discharged with a vacuum pump. _CO2 and non-condensable gases lighter than water vapor from this inlet exhaust rise to the _CO2 cooler _located higher than the steam cooler, where the _CO2 is further cooled to -13°C with the liquid refrigerant -183°C oxygen. and is discharged (collected) by the vacuum pump.

In the present invention, the operating pressure of the combustion chamber of the gas boiler is set to 1 atm, and based on this, the exhaust heat of the combustion chamber, as described above, subtracts the driving power of the compressor, and 78% net heat compared to (Net) exhaust heat is recovered. However, if the operating pressure of the combustion chamber is increased to 5 bar, the 0.2 bar 90 ° C steam-condensate steam can be heated to 150 ° C, and can be heated to 580 ° C (Boost up) with a compressor, and the composite recycle nitrogen can be heated to 560 ° C. Since the temperature can be raised by , 90% net heat compared to the exhaust heat can be recovered. On the other hand, in all steam turbines, the amount of exhaust heat amounting to 50% of the amount of heat added to the steam is released to the sea. However, in the future, with the exhaust heat recovery method of the present invention, 70% or more of the exhaust heat reaching this 50% can be recovered, so that all steam turbines are expected to have thermal efficiencies of at least (Net) 75% or more.

In gas boilers for steam turbines, circulating steam is recirculated to the combustion chamber as a working fluid, and oxygen and nitrogen are separated and produced from air and used as refrigerants, realizing pure oxygen combustion, and exhausting the combustion chamber while maintaining a constant pressure in the combustion chamber. (Intake) flows into this exhaust cooler, and uses the enormous evaporation heat of (preceding exhaust) as cooling heat to cool the inflow exhaust from the subsequent combustion chamber, so that the inflow exhaust from the combustion chamber is condensed, and the vast amount of exhaust heat thereof is recovered. , CO ₂ is captured, hydrogen is produced from this CO ₂ , and ammonia (NH ₃ ) is produced from this hydrogen and nitrogen used as a refrigerant for pure oxygen combustion, so that carbon (CO2 Net Zero) neutrality is realized. It is characterized by

Code Description None.

Claims (6)

In a gas boiler for a steam turbine of a thermal power plant, oxygen and nitrogen produced separately from air are used as refrigerants, only oxygen is injected into the combustion chamber, 80 mol% circulating water is preheated as a working fluid, injected into the combustion chamber, and recirculated, resulting in pure oxygen combustion. is implemented,
(Claim 2) While maintaining a constant pressure in the combustion chamber, the combustion chamber exhaust is discharged through the power generator (Fig. 6) and introduced into the exhaust cooler (Fig. 2), so that the power generator is connected to the bypass passage. In addition, it is installed at the rear end of this combustion chamber, and the exhaust from this combustion chamber enters (suction) into this exhaust cooler,
(Claim 3) The group-condensate (of the preceding exhaust) cools the exhaust inflow to the combustion chamber in the exhaust heat absorber (FIG. 2), absorbs its (condensate) exhaust heat, with enormous evaporation heat as a refrigerant, 90 The temperature is raised to ℃ steam, (FIG. 5) is sucked into the vacuum pump of the exhaust heat recovery system and transferred to the steam (StmHtr) heater,
Cold and water vapor spray is blown from the ceiling, the vapor is cooled by the refrigerant oxygen in the vapor cooler, and the vapor is finally condensed, and the condensate collected in the hot well is transferred to the exhaust heat absorber tube , Inlet exhaust is cooled with enormous heat of evaporation, the temperature is raised to 90 ° C steam, and CO ₂ is cooled (captured) to -13 ° C with liquid refrigerant oxygen in the CO ₂ cooler (captured) and discharged,
(Claim 4) (Fig. 5) In the steam (StmHtr) heater of the exhaust heat recovery system, steam at 90 ° C is heated to (Boost up) to 120 ° C or higher with (133 ° C) recirculating nitrogen by means of a heat pump. After heating to 310℃ or higher, pressurized to 1 atm or more, (628 mol% 87℃) is cooled with complex recycle nitrogen (100℃) condensate, and circulating steam (80 mol%) condensate is pressurized to the combustion chamber operating pressure, and this (condensate ) Among the circulating water, most (86%) of the circulating water (FIG. 5) circulating water (CircWtr PreHtr#1) is preheated to 270 ° C. or higher in the preheater #1,
(Claim 5) The remaining (14%) circulating water, (FIG. 4) Circulating water (CircWtr PreHtr#2) In preheater #2, 1 atm nitrogen in the nitrogen storage tank is cooled and liquefied (FIG. 5) in the turbine exhaust heat recovery system To supply the necessary liquid nitrogen, 20 bar 620 ℃ nitrogen is cooled to 120 ℃, preheated to 620 ℃ or more, and this 120 ℃ 20 bar nitrogen is pressurized at 30 bar to liquefy into a liquid refrigerant, the second (2nd N ₂ Cooler) is injected into the cooler,
(Claim 6) The inflow exhaust CO ₂ produced by combustion is cooled (collected) to -13°C in the exhaust cooler (FIG. 2) and discharged, pressurized to 1 atm. In the external (CO ₂ ExCooler) CO ₂ cooler, refrigerant oxygen It is cooled to 5 ℃, dissolved in 5 ℃ cooling water, (Fig. 1) with carbonated water in a mixer (Mixer), supplied to the system where hydrogen is produced, and hydrogen is produced, with this hydrogen and nitrogen used as a refrigerant, Ammonia (NH ₃ ) is produced, thereby realizing carbon (CO ₂ Net Zero) neutrality, a thermal power plant gas boiler exhaust cooling exhaust heat recovery and CO ₂ capture device, heat pump, and carbon neutral operation method by gas-condensation heat of vaporization.
The method of claim 1, while maintaining a constant pressure in the combustion chamber, the combustion chamber exhaust is discharged through the power generator (Fig. 6) and introduced into the exhaust cooler (Fig. 2), the power generator is located at the rear end of the combustion gas outlet of the combustion chamber. , In addition, this bypass passage, in which the flow rate flowing to the bypass passage through the diffuser with the flow control valve (Diffuser) is controlled, is mounted, so that the combustion chamber exhaust is supplied to the present exhaust cooler with a back pressure of 0.2 bar of 110 ° C (suction ) A thermal power plant gas boiler exhaust cooling exhaust heat recovery device by multiple evaporation heat configured to flow in. The method of claim 1, (FIG. 2) in this exhaust cooler, (FIG. 7) at the inlet through which exhaust (suction) flows from the power generator,
An exhaust heat (Exh.Heat Absorber) absorber is installed, then an exhaust mini cooler is installed, and then, cold gas is sucked from the ceiling above the CO ₂ cooler chamber on the far right (CO ₂ Cooler) to the ceiling. emanating from
A plurality of cold air circulation pipes are installed, and a cold air circulation (FIG. 3) blade is installed at the T-junction above the cold air circulation pipe inlet, and above the T-junction, O ₂ , CO, N ₂ , and other non-condensable gases. A collection space is formed, and a vacuum pump is installed to eject and discharge this non-condensable gas, and then, as condensed gas that has already been cooled and condensed, steam spray is spewed from the ceiling.
A plurality of water spray nozzles are installed, and then a circulating water (Vapor Cooler) cooler is installed, in which refrigerant oxygen flows into the tube and cools the inlet exhaust,
Below, (Hot Well), a condensate pump is installed so that the (group-plural) condensate of the hot well is transferred to the exhaust heat absorber tube, and in this exhaust heat absorber, the steam-condensate uses the enormous evaporation heat as cooling heat, While evaporating with steam, cooling the subsequent inflow exhaust, absorbing enormous condensation heat, and raising the temperature to 90 ° C steam, the inflow exhaust is cooled,
On the far right, a (CO ₂ Cooler) CO ₂ cooler is installed, in which the refrigerant oxygen flows into the tube higher than the steam cooler and the CO 2 produced by combustion is cooled. Below this _{CO 2 cooler} , CO cooled below zero ₂ is installed with a vacuum pump that sucks (collects) and discharges
The inflow exhaust is directly cooled with cold air and water vapor spray blown from the ceiling, the steam in the inlet exhaust is condensed, and in the circulating water cooler where the refrigerant oxygen flows through the tube, it is further cooled and the steam is finally condensed, and then in the exhaust. Oxygen in excess, lighter than water vapor, Non-condensable gas such as CO ₂ rises to the upper CO ₂ cooler, and in this CO ₂ cooler, CO ₂ is cooled to -13℃ with oxygen as a refrigerant, and is sucked (collected) and discharged by the vacuum pump installed below the cooler, and is discharged from the hot well. (Group-plural) Gas boiler exhaust cooling exhaust heat recovery and CO ₂ capture device for thermal power plant gas boiler exhaust by condensate evaporation heat, configured to transfer condensate to the exhaust heat absorber tube. The method of claim 1, wherein the 90° C. mild steam that absorbed the inflow exhaust heat is heated to 120° C. or higher (Boost up) with 133° C. or higher composite recycle nitrogen in the exhaust heat recovery system (FIG. 5), and pressurized to 1 atm or higher to 310° C. After the temperature rises above (StmCond), in the condenser, 628 mol% 86 ° C composite recycle nitrogen is cooled to 100 ° C, and this nitrogen is heated to 290 ° C or higher, and the enormous exhaust heat of steam is converted into the heating heat of the heat transfer medium steam , Then, this 100 ° C) (plural) circulating water is preheated to 270 ° C or higher with 290 ° C nitrogen holding exhaust heat as a heat transfer medium in most (86%) of the circulating water (CircWtr PreHtr # 1) preheater # 1, Gas boiler exhaust cooling exhaust heat recovery heat pump operation method by gas-condensation heat of evaporation. The method of claim 1, wherein the remaining (80 mol% x 14%) small amount of circulating water (FIG. 4) circulating water of the nitrogen liquefaction cooling system (CircWtr PreHtr#2) in the preheater #2, 1 atm 110 ° C. nitrogen in the primary compressor Compressing at 20 bar, raising the temperature to 650 ° C, and preheating to 620 ° C or higher with this nitrogen, this nitrogen is cooled to 120 ° C, pressurized at 30 bar, (Fig. 5) to liquefy into a liquid refrigerant required in the exhaust heat recovery system 2 The low-temperature nitrogen injected into the primary (2nd N ₂ Cooler) cooler and cooling this 30bar compressed nitrogen in the secondary cooler is mostly stored in the low-temperature nitrogen tank, and 1atm nitrogen is not compressed below 650℃ in the primary compressor. The flow rate re-input to the compressor is controlled so as to be mixed with the high-temperature nitrogen storage tank nitrogen and re-input to the compressor. The method of claim 1, (FIG. 2) CO ₂ generated by combustion in the exhaust cooler is collected at -13 ° C, pressurized at 1 atm with a vacuum pump, heated to 100 ° C, and then in an external (ExCooler) CO ₂ cooler, 5 Cooled to ℃, dissolved in carbonated water in 5 ℃ cooling water (Fig. 1) in a mixer (Mixer), supplied to a system that produces oxygen and hydrogen, hydrogen is produced, and this hydrogen and nitrogen used as a refrigerant are ammonia (NH ₃ ) A gas boiler exhaust cooling CO ₂ capture device and carbon-neutral operation method configured to achieve carbon (CO ₂ Net Zero) neutrality by being supplied to a manufacturing plant and producing ammonia.

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