Carbon dioxide capture system comprising a compressor and an expander and method of using such system

Abstract

The invention is a CO2 capture system comprising the following features: - a CO2 rich exhaust gas (6g) from an external first source (6s) to the inlet (6) of a compressor (2); and a first CO2 rich gas (6r) compressed at high pressure (P) reaches a manifold (8) to one or more outlets (5) of a housing (10) enclosing at least part of a combustion chamber (11) having a wall (11w), - wherein the combustion chamber (11) comprises a burner (13) arranged to combust fuel (14f) and compressed air (15c) supplied from a fuel line (14) and an air supply pipe (15) respectively at high pressure (P) to form a second CO2 rich gas (15r), - wherein a slit (12) is provided in the wall (11w) in the combustion chamber (11) for the compressed CO2 rich gas (6r) to enter to mix with the other CO2 rich gas (15r) formed in the combustion chamber (11) and cool to a third CO2 rich exhaust gas (60r); - a heat exchanger (16) arranged to operate at high pressure (P) and to exchange heat from the hot CO2 rich exhaust gas (60r) from the combustion chamber (11) with a returning CO2 lean exhaust gas (60L) from a CO2 extraction device (100) mainly at high pressure (P), - wherein the returning, now heated, CO2 lean exhaust gas (60L) is returned via a manifold (9) to an expander (3) and discharged via an outlet (7), the expander driving the compressor (2) and the CO2 extraction device (100).

Description

TECHNICAL FIELD

[0001] The invention is a CO2 capture process. In an embodiment of the invention, it is easily implemented by converting a gas turbine. The invention can, for example, be connected to another gas turbine producing 6 million watts or more, while virtually all the CO2 produced by the gas turbine can be extracted in a non-toxic manner, so that all the CO2 can be stored under pressure in a reservoir, or used as a pressure aid in oil production, or included as part of the raw material for industrial production. The inventors have thus arrived at an economically sustainable method.

[0002] More specifically, it is a CO2 capture method comprising the following steps:

[0003] - compressing a CO2-rich exhaust gas (6g) from an external first source (6s) by means of a compressor (2) and forming a compressed, first CO2-rich gas (6r) and, in order to predict the course of events, the compressed, first CO2-rich gas (6r) and a second CO2-rich gas (15r) formed in the process downstream of the compressor (2) are fed to a carbon capture circuit which returns a now CO2-lean gas (60L) (L for "lean material") to an expander (3) which is preferably connected to the same main shaft as the compressor (2), so that the energy in the CO2-lean gas (60L) is recovered. BACKGROUND

[0004] The applicant himself discloses a patent application WO2019172772 which uses a similar structure with a compressor, a combustion chamber and an expander, in which the flue gas from the combustion chamber is circulated in a so-called hot potassium carbonate (HPC) plant for heat exchange and CO2 extraction. SUMMARY

[0005] The invention is a device and a CO2 capture method comprising the following steps:

[0006] - compressing a CO2-rich exhaust gas (6g) from a [external] first source (6s) by means of a compressor (2) and forming a compressed, first CO2-rich gas (6r),

[0007] - in a combustion chamber (11), combusting a fuel (14f) by means of a burner (13) with compressed air (15c) and forming a second CO2-rich gas (15r) under pressure,

[0008] - mixing the compressed, first CO2-rich gas (6r) into the second CO2-rich gas and cooling it and forming a resulting pressurized, third CO2-rich gas (60r).

[0009] - the pressurized third CO2-rich gas (60r) is discharged through a heat exchanger (16) which exchanges the hotter third CO2-rich gas (60r) with the cooler returning pressurized CO2-lean gas from the CO2 extraction device,

[0010] - wherein the cooled, third CO2-rich gas (60r) is passed from the heat exchanger (16) to the CO2 extraction device through a conduit (17), wherein the resulting cooler CO2-lean gas (60L) is returned to the heat exchanger (16) through a conduit (18) and is heated by the heat exchanger (16),

[0011] - wherein the returning heated CO2-lean gas (60L) is expanded through an expander (3).

[0012] The apparatus and smaller features of the invention are defined in the set of claims attached. The Figure description

[0013] The invention is illustrated in the attached drawings, wherein, Figure

[0014] Figure 0 is a schematic representation of an embodiment of the invention configured with a converted SGT300 gas turbine, Figure and shows some of the central features of the embodiment of the invention, in addition to the CO2 extraction device which is not shown here, Figure ​A converted gas turbine for receiving a CO2 rich exhaust gas (6g) is shown in which the top of the original combustion chamber (19') is replaced with an outlet from a first manifold (8) for delivering compressed first CO2 rich gas (6r) to one or two silo combustion chambers (11) for supplying compressed air with a supply of fuel NG (14f), where the cooler supplied first CO2 rich gas (6r) is mixed and cooled with another CO2 rich gas (15r) resulting downstream of the combustor (13) and forms a third CO2 rich gas (60r) that reaches an undesirably high temperature and is delivered via a second manifold (9) through a heat exchanger (16) to and from a CO2 extraction device into the stem of the original combustion chamber as a CO2 lean gas (60L) for discharge via an expander (3). The combustion chamber (11) burns compressed air (15c) and fuel (14f) to produce a balanced, second CO2 rich exhaust gas (15r) that will be mixed and cooled downstream with the first CO2 rich exhaust gas (6c) to form the third CO2 rich gas (60r). 19' is the original combustion chamber on the gas turbine casing and shows that the combustor has been removed to form the outlet of the first manifold (8) for the CO2 rich exhaust gas (6g) and for the CO2 lean gas (60L) to return from the second manifold (9) under pressure. 6 is the intake for the CO2 rich exhaust gas (6g). 3 represents the expander for the CO2 lean gas (60L). For example, the illustrated SGT300 industrial gas turbine originally has an output of 62 MW and a pressure ratio of 38:1.

[0015] Figure 1 An embodiment of the invention is shown in more detail and gives an overview of the combustion chamber (11) with a wall (11w) with slits (12) to cool the first CO2 rich gas (6r). The CO2 rich exhaust gas (6g) from a first source (6s) is fed into a compressor (2). A heat exchanger (16) receives additional combustion gas from the combustion chamber (11) and the first CO2 rich gas (6r) and exchanges heat with a CO2 lean gas (60L) from a CO2 capture device through a pipe (18). The additional combustion gas is cooled by the CO2 lean gas (60L) and is delivered to the combustion chamber (11) through a second manifold (9) as a second CO2 rich gas (15r) that is mixed and cooled with the first CO2 rich gas (6r) to form a third CO2 rich gas (60r) that is delivered to the CO2 extraction device through the heat exchanger (16) as a CO2 lean gas (60L) for discharge through the expander (3). The CO2 lean gas (60L) is cooled by the CO2 rich exhaust gas (6g) in the heat exchanger (16) and is delivered to the combustion chamber (11) through the second manifold (9) as a second CO2 rich gas (15r) that is mixed and cooled with the first CO2 rich gas (6r) to form a third CO2 rich gas (60r) that is delivered to the CO2 extraction device through the heat exchanger (16) as a CO2 lean gas (60L) for discharge through the expander (3). Figure Reference (1) represents a converted gas turbine in which the combustion chambers on the casing have had their combustion heads removed as described above, the outlets 5 from the casing and the outlets 5 back to the casing are the same as the outlets on the gas turbine (1) from which the gas turbine takes its name. The ordinary combustion chambers end before conversion. Here, the outlets (5) direct the first CO2 rich gas (6r) onto a ring-shaped first manifold (8) and further onto an enclosure (10) that surrounds the combustion chamber (11). In one embodiment, there is an inclined outlet to the combustion chamber (11).

[0016] The generator (G) is on the cold side and serves as a starter motor and after start-up delivers virtually only energy to the CO2 capture process.

[0017] Normally, in the original gas turbine (1) we need to cool the expander (3), which is now not necessary because we run at such low temperatures. (4) indicates the cooling line which is now unnecessary.

[0018] Hereby the design and construction of the heat exchanger (16) becomes easier by only obtaining 760°C from the combustion chamber (11) instead of 1050°C, because we can use "off the shelf" heat exchangers instead of high temperature resistant heat exchangers HE. The unburnt oxygen from the flue gas does not participate in the combustion because it flows in through the slits (12) after combustion between the gas (14) and the compressed air (15) at the top of the combustion chamber (11), so it only cools the combustion gas (15r).

[0019] The fuel line (14) feeds the combustor (13) with natural gas NG (14f).

[0020] The slits (12) are formed in the wall (11w) of the combustion chamber (11), where the first CO2 rich gas (6r) from the outer shell (10) is mixed into the combustion chamber (11) only after combustion to dilute the second CO2 rich combustion gas (15r). The first CO2 rich gas (6r) from the compressor does not participate in the new combustion, it only needs fresh compressed air (15c) and new gas (14f), preferably natural gas (NG).

[0021] The compressed air (15c) from the compressed air line (15) at the top of the combustion chamber (11) feeds the combustor (13) with air, which discharges the combustion gas (15r) from (13) with T = 1800°C - 1900°C, but with a volume of only about 1 / 5 of the first CO2 rich gas (6r). We thus avoid manufacturing a combustor that will burn with a low oxygen content, which will greatly simplify and we can use a normal gas combustor.

[0022] The flue gas (first CO2 rich gas (6r)) from the compressor (2) in the outer shell (10) cools the wall (11w) in the combustion chamber (11). (11w) indicates the wall (11w) in the combustion chamber (11).

[0023] The exhaust gas (7) from the expander (3) has a low CO2 content.

[0024] Figure The temperature is shown in the middle for example 350°C - 500°C, which depends on the pressure from the compressor. The FigureThe mark (5) is the outlet (5) of the compressed first C02-rich gas (6r) from the compressor (2). At a pressure P = 13 bar, T = typically 350 degrees Celsius.

[0025] In this Figure embodiment, the heat exchanger (16) in this embodiment is free of the complexity of a gas supply (15) cooling the shell of the heat exchanger (16), as Figure 4 indicated.

[0026] A significant advantage of this arrangement is that, since it is not necessary to use a combustor designed to burn the compressed first C02-rich gas (6r) with a greatly reduced O2 content, but rather a combustor (13) in which compressed air (15c) and pressurized fuel (14f) are injected upstream of the combustor (13); it is possible to use a common combustor almost "off the shelf" and with a common mixing ratio between gas and fuel, which provides economic savings in terms of structure and calculation, and the combustion of the fuel (14f) is cleaner without having to make special modifications. In one embodiment, the combustion chamber (11) is equipped with ceramic tiles, in which the cooler first C02-rich gas (6r) cools the walls (11w) of the combustion chamber (11). The low flue gas outlet temperature from the combustion chamber (11) helps to prevent corrosion. This also means that if the temperature in the combustion chamber is about 1500g degrees Celsius, which is the normal initial temperature of the expander in modern gas turbines, a cheaper steel quality can be used.

[0027] Figure 2 The perspective Figure view shows the outlet (5) of the compressed first C02-rich gas (6r) from the compressor (2) via a coaxial shell (19) (i.e., where one coaxial "combustor shell") and the inner coaxial return of the shell of the return C02-lean gas (60L) that should return to the expander (3) at a pressure (P). In this case, the shell is oriented obliquely with respect to the axis of the converted gas turbine (2, 3), as Figure 1 indicated. In addition, FigureThe radial outlet from the outlet (5) to the annular first manifold (8) further leading to the outer shell (10) surrounding the combustion chamber (11) and the return from the heat exchanger (16) for the lean C02 gas (60L) back to the annular second manifold (9) which returns to the expander (3). A considerable advantage of this arrangement with annular manifolds is the uniform thermal expansion around the housing which prevents thermal stresses in the equipment. The annular second manifold (9) returns to the expander (3). The annular first manifold (8) leads to the outer shell (10) surrounding the combustion chamber (11).

[0028] Figure 3 is an improvement over Figure 1 and corresponds to the view from above Figure 4 and shows an embodiment of the invention which constitutes an improvement over the embodiment of Figure 2 . Figure 3 is a schematic principle of the converted gas turbine Figure The converted gas turbine comprises in the invention a compressor (2) in the upper left and an expander (3) to the right of the plate material. The coaxial housing (19) is the original "burner housing" of the original combustion chamber, now without the ordinary burner top and connected to the annular first manifold (8) and second manifold (9). The compressed first C02 rich gas (6r) from the compressor (2) pours into the section and outline of the converted burner housing (19) and into the section of the first return annular first manifold (8) further to the burner (11) and is cooled in the heat exchanger (16) and output from the heat exchanger (16) to the C02 extraction equipment from which the lean C02 gas (66L) is returned to the HTHP heat exchanger (16). New in this embodiment is that the compressed air line cooling shell in that it enters the top of the HTHP heat exchanger (16) and as the line (15) continues to run to the top of the combustion chamber (16) is still under pressure (P) but is now preheated and injected with fuel (14f) and ignited by the burner (13). The compressed air (15) comes from a separate electrically powered compressor. This can be pressurized so that the entire system is preheated before starting the entire process. The electric motor can be powered by the electricity from a coal power plant which can also be the first source (6s) of the C02 rich exhaust gas (6g).

[0029] Compressed air (15c) (from a separately driven electric compressor) enters (15) via heat exchanger (16) and is finally fed into the top of the combustion chamber (15) which delivers the gas to the burner (13). The T = 1800-1900 of the combustion gases which exit from (13) but its volume is only about 1 / 5 of the flue gas. Thus we avoid manufacturing burners which will burn with lower oxygen content which will greatly simplify.

[0030] Figure 4 Also relative to Figure 1 improvements and corresponding to Figure 3 but it is a partial section and view of the combustion chamber (11) in the first manifold (8) and second manifold (9) and housing (10) which are annular. Figure The compressed air (15c) in the compressed air line (15) cools the shell on the heat exchanger (16). The compressed air (15) which is introduced into the combustion chamber (finally) enters downwards and cools the housing (16) and continues (15) to the combustion chamber (11). Thus we can regulate the temperature in the combustion chamber (11) while cooling the walls of the heat exchanger (16). The compressed air (15) flows at 350 degrees Celsius on top of the heat exchanger (16) and is heated to about 400 degrees Celsius and further flows at T = about 400 degrees Celsius into the top of the combustion chamber (11). It helps that the housing of the heat exchanger (16) has such a low temperature that it can be more easily and with thinner steel manufactured compared to operating at higher temperatures.

[0031] Furthermore, the vertical part of the heat exchanger (16) is shown with a gas-cooled shell for the compressed air supply which forms part of the compressed air path in the pipe (15) which ends at the top of the combustion chamber (11).

[0032] In the present invention there is no need for coaxial pipes between the combustion chamber (11) and the heat exchanger (16) and between the heat exchanger (16) and the annular second manifold (9). The explanation for this is that the diameter of these pipes is about 1 meter and we can use high-quality steel which can withstand the current temperatures, thus avoiding the necessary coaxial cooling shell in our own process. At this lower temperature we avoid high-temperature oxidation of the steel.

[0033] Figure 4 In the attached Figure label (17) the third CO2-rich gas (60r) to the CO2 extraction device is shown and in the attached Figure label (18) the CO2-lean gas (60L) from the CO2 extraction device is shown.

[0034] Figure 5 is according to Figure 3 and4 One embodiment of the present invention, and a cross section and partial view viewed axially along the axis of the compressor (2) and expander (3). Figure This diagram shows an annular manifold and at least one of two possible pairs of combustion chambers (11) and heat exchangers (16). Figure It can be symmetrical; only half is shown here. There can be two combustion chambers (11) and two heat exchangers (16) connected to a common or two separate CO2 capture unit, and in this embodiment, the casing (19) enters and exits from manifolds (9) and (8) respectively, is radially oriented, and thermal stress becomes very low. Figure It can be symmetrical; only half is shown here. There can be two combustion chambers (11) and two CO2 extraction devices.

[0035] There is a radial outlet leading to the combustion chamber (11). This is the location of the old combustion chamber (19') of the gas turbine. One of the purposes of this conversion gas turbine (1) is to compress air and not actually produce energy for output, even though the process releases energy overall. Therefore, we take an existing gas turbine generator and convert it into the present invention, which includes a compressor to obtain purified CO2 gas in an efficient and advantageous manner. Therefore, we convert CO2 to K2CO3 – “hot potassium carbonate” – at high partial pressure, a method that requires high pressure. HPC is a non-toxic, harmless, and environmentally friendly CO2 capture process. The annular line / first manifold (8) and second manifold (9) are advantageous. Here, since the radial line is radially oriented, there is no thermal stress.

[0036] Figure 6 A perspective view of the SGT A-65 "Industrial Trent 60" aero-derivative gas turbine. Figure The gas turbine is convertible for use in this invention, wherein the gas turbine is shown here, after conversion becoming a generator (G) on the left, an inlet (6) for CO2-rich exhaust gas (6g), a compressor (2), a burner housing (19) (which will be removed to convert to the present invention) having a burner top, and converted into a housing (19) for outlet and return, and an expander (3) on the right. The radial housing (19) corresponds to Figure 3 and 5 The location shown.

[0037] Figure 7 This is the process of the CO2 extraction device included in the embodiments of the present invention. Figure The heat recovery unit (24) has a water inlet temperature of 136°C and a flue gas temperature of 94°C from (21), with a temperature difference of 42°C.

[0038] Figure 7The stripping column (22) is shown, where the absorption fluid flows out from the lower part of the stripping column (22), is heated in a heating unit, reboiler (31) in counterflow with flue gas, and then back up to the stripping column (22).

[0039] The chemical reaction in the stripping column, for example at 1 bar: 2 KHCO3 + heat -> K2CO3 + H2O + CO2 (released).

[0040] Figure 7 The heating unit (31) or reboiler is shown, for heating the absorption liquid.

[0041] The heating unit (31) (reboiler) is supplied with heat from flue gas from the downstream SCR (30).

[0042] Figure 7 The self-cleaning filter (26) is shown.

[0043] Figure 7 The absorber (21) is shown, which is operated at high pressure, 12 bar or higher, and the absorption fluid hot K2CO3 + H2O is sprayed into the top of the absorber (21).

[0044] CO2 + K2CO3 + H2O -> 2 KHCO3 + heat

[0045] P -> 12 bar,

[0046] or P -> 16 bar

[0047] or P -> 19 bar

[0048] Figure 7 The heat exchanger HE (23) is shown, which heats K2CO3 for the absorber (21), and the heat exchanger HE (23) cools 2 KHCO3 to the stripping column (22).

[0049] Figure 7 The centrifuge (28) is shown, which separates water from the cooled flue gas.

[0050] Figure 7 The SCR-unit (30) for NOx capture is shown, ideally at 270°C.

[0051] Figure 0 The CO2-rich gas from the SCR (30) to the reboiler (31) is shown. DETAILED DESCRIPTION

[0052] The invention is a CO2 capture system, comprising the following features:

[0053] - CO2-rich exhaust gas (6g) from an external first source (6s) to the inlet (6) of the compressor (2); and the first CO2-rich gas (6r) compressed at a pressure (P) to the first manifold (8) to one or more outlets (5) of a housing (10) enclosing at least part of a combustion chamber having a wall (1 1w),

[0054] - wherein the combustion chamber (1 1) comprises a burner (13) arranged to combust fuel (14f) and compressed air (15c) supplied from a fuel line (14) and an air supply pipe, respectively, at the pressure (P) to form a second CO2-rich gas as a combustion gas, wherein a slit (12) is provided in the wall (1 1w) of the combustion chamber (1 1) for the compressed first CO2-rich gas (6r) to enter to mix and cool down to a third CO2-rich gas (60r) with the combusted CO2-rich gas (15r) formed in the combustion chamber (1 1) (note that the compressed first CO2-rich gas (6r) does not substantially participate in the combustion of the fuel (14f) and compressed air (15c); it enters downstream combustion, diluting the other CO2-rich gas (15r));

[0055] - a heat exchanger (16), preferably a heat exchanger, arranged to operate preferably at a pressure (P) higher than 12 bar, and at substantially the same pressure (P), to exchange heat from the hot third CO2-rich gas (60r) from the combustion chamber (1 1) with the returned CO2-lean gas (60L) from the CO2 extraction device,

[0056] - the returned, now heated, CO2-lean gas (60L) is guided back to the expander (3) via the second manifold (9) and is discharged via a second outlet, the expander (3) driving the compressor (2) and the CO2 extraction device.

[0057] According to the invention, the compressed air (15c) only causes combustion of the fuel (14f) at the burner (13) and forms a second CO2-rich gas (15r), and the mixing with the first CO2-rich gas (6r) from the compressor (2) first occurs downstream of the formation of the other CO2-rich gas (15r). This is a fundamental aspect of the invention. Thus, the compressed air (15c) can be introduced into the burner (13) only and combusted with the fuel (14f) without mixing with the oxygen-lean compressed first CO2-rich gas (6r) from the compressor (2). This means that a common burner (13) can be used and the combustion of the fuel at low oxygen concentration is avoided, which simplifies the device, provides faster and easier combustion and reduces the resulting temperature in the resulting third CO2-rich gas (60r).

[0058] The invention is a CO2 capture process. More specifically, it is a CO2 capture method comprising the steps of:

[0059] - by compressing the CO2 rich exhaust gas (6g) from the external first source (6s) by the compressor (2) and forming a compressed first CO2 rich gas (6r), and, for the sake of predicting the course of the event, the compressed first CO2 rich gas (6r) and a second CO2 rich gas (15r) formed in the process downstream of the compressor (2) together form a third CO2 rich gas (60r) which is sent out to the carbon capture circuit which returns now a CO2 poor gas (60L) (L for "lean material") to the expander (3) which is preferably connected to the same main shaft as the compressor (2) so that the energy in the CO2 poor gas is recovered.

[0060] Attention is drawn to several points:

[0061] a) This, namely the invention, is not a gas turbine, but looks like one. But the difference is absolutely necessary. Advantageously, a converted gas turbine is used which has a relatively small starting point modification, which is itself a gas turbine and can use existing "off-the-shelf" gas turbines, such as the "SGT-300 industrial gas turbine" with gas burners inclined with respect to the turbine axis, see Figure 6 or the "SGT-A65 (industrial Trent 60) aeroderivative gas turbine", see Figure 4 with radial gas burners with respect to the turbine axis, and wherein the compressor (2) and the expander (3) are used as originally designed and in relation to each other, and in both cases, the top of the burner is dismantled and the compressed gas flow is broken off to flow through a part of the combustion chamber, and the gas flow is indirectly returned to the expander.

[0062] b) The significant difference between the gas turbine and the invention is that the gas turbine generates, by its cold end connected to the shaft, an electrical generator, the energy is output, while in the invention the energy in the compressed first CO2 rich gas (6r) and the additional energy generated in the combustion chamber (11) are improved / adjusted by the invention itself for driving the CO2 capture method, including the CO2 recovery device which itself requires energy, and for driving the second compressor which delivers compressed air and fuel into the combustion process.

[0063] c) By the CO2 extraction device, a certain amount of CO2 is withdrawn. To compensate for this amount of CO2 gas withdrawn between the compressor (2) and the expander (3), in this process, fuel and compressed air are supplied to the combustor in the combustion chamber. The amount of gas and fuel supplied, adjusted according to the "loss" share of CO2, forms a certain amount of CO2-lean gas (15L) which balances the amount through the expander (3) so that a "standard" gas turbine can be formed using the compressor (2) and the expander (3) without the need for upgrading the support bearings, which can be converted for our use. In other words: the system is actually a converted gas turbine designed to drive a generator, which delivers to a high-efficiency compressor, which delivers the flue gas to the device for pressurized capture of CO2, and in which a compensation gas volume is formed for the total extraction of CO2 by burning air and fuel in order to balance the amount through the compressor with the amount through the expander.

[0064] d) The method of the invention does not steal energy from the possible CO2-rich exhaust gas (6g) of its own gas turbine, which consumes the energy of the fuel (14) supplied in its own method. This fuel (14) itself is the cost of running the method, and it is obviously spent on what it does, but under the main condition that the CO2 captured in the CO2 recovery device will be paid for, since in addition to the oil producers paying for the use of CO2 to increase oil production, the United States offers a tax credit for every ton of CO2 captured, so-called EOR: enhanced oil recovery. A significant advantage of the invention is that in the present method, for every ton of carbon dioxide captured, as much (or more) compensation can be obtained as is consumed in our current method.

[0065] e) The invention enables a significant increase in the pressure (P) in the flue gas to at least 8 bar, preferably higher than 12 bar, or higher than 16 bar, or more preferably higher than 19 bar, and thus largely reduces the volume and thermal requirements of the CO2 capture device, while enabling the pressurized capture process as an embodiment of the invention in the CO2 extraction device.

[0066] f) The significant difference is that the invention can advantageously make use of the gas turbine gas combustor casings and their coaxial return tubes, and remove their tops, and fit a transition to the first manifold (8) for the outlet as compressed exhaust gas (6c) and to the second manifold (9) for the return of the return part as CO2-lean return gas (6L, 15L) to the expander. Roughly speaking, on the first manifold (8) a large silo combustion chamber (11) is connected, in which the combustion chamber (11) is connected to a heat exchanger (16) and to the CO2 extraction device, and in which it is returned via the heat exchanger (16) to the second manifold (9) and to the expander (3).

[0067] g) The significant difference with our own method is that the combustion chamber (11) is not a re-combustion chamber, but a combustion chamber. The difference is significant. In the present invention there is no apparent re-combustion, but the mixture of compressed exhaust gases (6c) that dilutes and cools the C02-rich combustion gases (15r) formed by the compressed air (15c) and the fuel (14f) that is burned in a part of the combustion chamber before the very hot C02-rich combustion products (15r) are formed in the combustion chamber (11) are mixed with cooler exhaust gases. A very important advantage of the present invention is that in this new way higher temperatures are not generated in the combustion chamber and in the outlet part of the heat exchanger, so that in the heat exchanger (16) which can be a high pressure heat exchanger, a common type of steel can be used and thus very expensive steels are avoided and in other respects high temperature corrosion (oxidation) is avoided, which would otherwise be subjected to a full re-combustion (which has been avoided in the present invention) in a high pressure - high temperature heat exchanger developed at particularly high temperatures.

[0068] The loss of pressure (P) in the C02extraction device is negligible, in the range of 0.4 bar.

[0069] Regulation system

[0070] In one embodiment of the invention, the system has a regulation system arranged to regulate the supply of compressed air (15c) and fuel (14f) to be substantially equal to the amount of C02extracted in the C02extraction device, so that the amount of gas that flows over the expander (3) corresponds to the amount of gas that flows in through the compressor (2).

[0071] Pressure conditions

[0072] In one embodiment of the invention, therefore, the pressure in the C02capture system, which comprises the outlet of the compressor (2), the first and second manifolds (8, 9), the combustion chamber (11), the heat exchanger (16), the C02extraction device and the inlet of the expander (3), is arranged so that the pressure (P) in the C02-rich gas (6r, 15r, 60r) and the resulting C02-lean gas (60L) is higher than 12 bar, preferably higher than 16 bar, more preferably higher than 19 bar.

[0073] C02extraction based on K2C03

[0074] According to one embodiment of the invention, the C02extraction device is a so-called hot potassium carbonate K2C03device, wherein the C02extraction device comprises an absorption column (21) that is operated at a pressure (P) and with an absorption medium comprising a mixture of water and potassium carbonate K2C03, wherein the reaction in the absorption column (21) is:

[0075] C02+ K2C03+ H20 = 2 KHC03.

[0076] Generator and starter motor

[0077] According to one embodiment of the invention, a generator / starter motor (G) is connected to the compressor (2) and the expander (3), which are preferably mounted on a common shaft, and preferably on the cold side of the inlet (6), and wherein the generator (G) generates energy recovered in the expander (3) to drive the process in the compressor (2), the CO2 extraction plant and the system as a whole.

[0078] In another embodiment, the generator / starter motor (G) is connected to the compressor (2) and arranged to pressurize the system before starting, and wherein the energy to the motor (G) is taken from outside, from the mains or preferably from a generator in a thermal power plant, which also produces the first source (6s), which is a CO2 rich exhaust gas.

[0079] In one embodiment of the invention, the combustion chamber (11) is a silo combustion chamber (11).

[0080] Annular manifold

[0081] In one embodiment of the invention, the first manifold (8) and the second manifold (9) are arranged as an annular manifold, which is arranged around a housing (19) and is connected to the outlet (5) from the compressor (2) and to the return to the expander (3), wherein the housing (19) otherwise constitutes a burner of an original combustion chamber (19') on a converted gas turbine, but the burner top has been removed.

[0082] In one embodiment of the invention, the outlet (5) of the compressor (2) is a coaxial outlet (5) around a modified return around the housing between the compressor (2) and the expander (3), which otherwise serves as a burner of an original combustion chamber (19') in a gas turbine.

[0083] Preheating of compressed air

[0084] According to one embodiment of the invention, the compressed air line (15) passes a cooling shell on the heat exchanger (16), which is arranged to cool the pressure shell of the heat exchanger (16), which preheats the compressed air (15c) before injection at the top of the combustion chamber (11) (see Figure 7 ).

[0085] In one embodiment of the invention, the lower part of the combustion chamber (11) in the housing (10) is clad on the inside with ceramic bricks for shielding against radiant heat from the combustion process of the fuel (14f) and compressed air (15c) at the burner (13).

[0086] The method of the invention

[0087] Above we have described a system for CO2 capture. Below the method of the invention will be described accordingly, which is a CO2 capture method, comprising the following steps:

[0088] - compressing the CO2 rich off-gas (6g) from the external first source (6s) by means of a compressor (2) and forming a compressed first CO2 rich gas (6r),

[0089] - combusting fuel (14f) in a combustion chamber (11) by means of a burner (13) with compressed air (15c) and forming a second CO2 rich gas (15r) at a pressure (P),

[0090] - mixing the compressed first CO2 rich gas (6r) into the second CO2 rich gas and cooling and forming a resulting pressurized third CO2 rich gas (60r);

[0091] - the pressurized third CO2 rich gas (60r) is discharged through a heat exchanger (16), preferably a high pressure, high temperature heat exchanger, which heat exchanger (16) exchanges the hotter third CO2 rich gas (60r) with a cooler returning pressurized CO2 lean gas (60L) from the CO2 extraction plant,

[0092] - wherein the cooled, third CO2 rich gas (60r) is passed from the heat exchanger (16) through a conduit (17) into the CO2 extraction plant and wherein the resulting cooler CO2 lean gas (60L) is returned to the heat exchanger (16) through a line (18) and heated by the heat exchanger (16),

[0093] - wherein the returning heated CO2 lean gas (60L) is expanded by means of an expander (3).

[0094] In one embodiment of the invention, because here we only obtain 760°C from the combustion chamber (11) and not 1050°C, the design and construction of the heat exchanger (16) becomes easier if additionally a re-combustor technology is used, because we can use a "ready-made" heat exchanger (16) instead of a high temperature resistant heat exchanger which can withstand temperatures up to 1050°C.

[0095] The basic advantage of the invention is to obtain pressurized combustion and pressurized cleaning. In one embodiment we now achieve flue gas from 6 up to 19.5 bar (or higher pressure) so that a high efficiency of the CO2 extraction plant is obtained and the footprint is significantly reduced. This increases the power efficiency and significantly reduces the cost of the process, including the process in which we are ourselves involved in the development.

[0096] In and out balance

[0097] According to one embodiment of the method of the present application, the supply amounts of compressed air (15c) and fuel (14f) are adjusted substantially equally with respect to the amount of CO2 extracted in the CO2 extraction plant, so that the amount of gas flowing over the expander (3) corresponds to the amount of gas flowing in through the compressor (2), i.e. the additional gas (15c, 14f) combusted in the combustion chamber, with its CO2 content adjusted, corresponds to the amount of CO2 taken out in the extraction plant, and thus it is possible to use the existing gas turbine structure as a basis for the embodiment of the present application. This saves a large amount of development costs and allows a large amount of time to be saved in the construction of the embodiment of the present application.

[0098] Pressure ratio

[0099] As mentioned earlier, in the process between the outlet of the compressor (2) and the inlet of the expander (3), the pressure in the CO2-rich gas (6r, 15r, 60r) and the CO2-lean gas (60L) is higher than 12 bar, preferably higher than 16 bar, more preferably higher than 19 bar.

[0100] Hot potassium carbonate process

[0101] In the CO2 capture method according to the present application, a so-called hot potassium carbonate (HPC) process is used in the CO2 extraction plant. Preferably, the CO2 extraction plant is operated mainly at the gas pressure of the gas (60r, 60L) corresponding to the gas of the compressor (2) and in the combustion chamber (11) and the heat exchanger (16) and further back to the expander (3). The expander (3) is operated at a pressure corresponding to the pressure in the combustion chamber (11) with a reduction of about 0.4 bar pressure drop in the pipes, heat exchanger, NOx absorption unit (SCR) (30), boiler (31) for heating the absorption liquid and centrifuge (28).

[0102] According to one embodiment of the present application, an absorption column (21) with an absorption medium is used in the extraction plant, which absorption medium comprises a mixture of water and potassium carbonate K2CO3, wherein the reaction in the absorption column (21) is

[0103] CO2 + K2CO3 + H2O = 2 KHCO3.

[0104] The equation is stoichiometrically balanced.

[0105] According to one embodiment of the method of the present invention, a generator / starting motor (G) is connected to the compressor (2) and the expander (3), preferably on a common shaft, and preferably on the cold side at the inlet (6), and wherein the generator (G) generates energy recovered in the expander (3) to drive the overall process in the compressor (2), the CO2 extraction plant and the system. The capacity of the generator will cover the auxiliary systems for the systems for pumping fuel, lubricating oil, compressed air, etc., the generator can be switched to function as a starting motor to cover the auxiliary systems of the overall process, so that the entire system can be pressurized using the compressor (2) before starting the burner (13), the CO2 extraction plant, the pressure injection of fuel (14f), the compression of the supplied supply gas (15c), the circulation of lubricating oil, etc.

[0106] According to one embodiment, the CO2 rich exhaust gas (6g) is supplied from an external gas turbine. In another embodiment, the source is a coal-fired power plant, a cement plant, a refinery cracker or a waste incineration plant, which supplies the CO2 rich exhaust gas (6g).

[0107] We then refer to Figure 1 :

[0108] The function of the converted gas turbine is mainly limited to compressing the flue gas from an external source, and generating sufficient power in the generator (G) to drive the auxiliary systems of the turbine. The generator (G) also has the function as a starting motor. The absorber (21) will work at a pressure (P) of 12 bar or higher. This means that an environmentally friendly absorbent with low selectivity can be used as potassium carbonate (K2CO3). In addition, the cost of the absorber (21) will be reduced to about 1 / 12 compared to absorption at atmospheric pressure. At atmospheric pressure, only absorbents with high selectivity can be used, such as monoethylenamine. Expensive chemicals are added to the MEA to reduce denaturation, corrosion, foaming and the formation of clogging stable salts. In addition, the flue gas emitted from such a plant to the atmosphere will contain carcinogenic chemicals, such as NIR-nitrosophenylamine. Even very low concentrations, greater than 1 nanogram per cubic meter, pose a health risk.

[0109] In one embodiment of the invention, the flue gas, the third CO2 rich gas (60r), has an inlet temperature at the heat exchanger (16) selected to be 760°C (see also Figure 1 ). The relatively low temperature of the flue gas is due to a reduced amount of natural gas supplied to the burner (13). By supplying only gas to the burner, compressed air (15c), a standard burner can be used. The heat exchanger (16) is operated at a flue gas temperature at a level that is sufficiently low to be purchased in the event of guaranteed operation. Also, the temperature is so low that high-temperature oxidation is avoided.

[0110] In one embodiment of the invention, hot third CO2 rich gas (60r) at a temperature of 275°C from heat exchanger (20) is passed to a nozzle (27) for feeding ammonia (NH3). Downstream of the nozzle, NH3 and flue gas are mixed in a tube with "guide vanes" upstream of a NOx capture unit (30) which can operate at a selective catalytic reduction unit (SCR). This unit preferably operates at an optimum temperature of 270 degrees Celsius. From the selective catalytic reduction (SCR) (30), the flue gas is directed by a pipe to a boiler (31) for heating the absorption liquid.

[0111] This arrangement reduces costs compared to conventional steam heating. The flue gas from the boiler (31) is passed to a centrifuge (28). The centrifuge separates water from the flue gas. This is very advantageous as it prevents the supply of water to the absorption liquid in the absorber (21) and contamination of the absorption liquid.

[0112] The water separated from the centrifuge (28) is passed to a self-cleaning filter (26). The water is passed from the filter (26) to a high pressure pump. The pressurised water is then passed to a nozzle in a heat recovery unit (24) so that the temperature of the flue gas from the absorber (21) is increased before entering the heat exchanger (20).

[0113] The gas burner (13) will therefore work in clean air.

[0114] An embodiment of the invention can be based on a gas turbine SGT5-2000E-187MW / 50Hz.

[0115] In the combustion chamber

[0116] The first CO2 rich gas (6r) does not flow into the top of the silo combustion chamber (11). Only compressed air (15c) and fuel (14f) are fed to the burners (13) in the top of the combustion chamber (11).

[0117] The first CO2 rich gas (6r) will be fed into the combustion chamber through slits (12) in the wall (11w) to cool and mix into the combustion gases (15r) from the burners (13).

[0118] Preliminary calculations:

[0119] Natural gas such as fuel (14f) fed to the burners (13): 4 Kg / sec

[0120] Pressurised air (15c) to the burners (13): 111 Kg / sec

[0121] Power supplied by the generator (G): 37 MW

[0122] Temperature of the exhaust gas, third C02 rich gas (60r) coming out of the combustion chamber (11) is: 756 degrees Celsius

[0123] Temperature of the returned C02 lean gas (60L) from heat exchanger (16) to expander (3): 700 degrees Celsius

[0124] Start-up of the system:

[0125] Electric power (60 Hz) provided to the static frequency converter (SFC) for:

[0126] - Generator / power starter (G)

[0127] - Clutch / gas turbine generator

[0128] Power consumers:

[0129] Air compressor: 43 MW / purchased 60 Hz electric power.

[0130] C02 output compressor (101); 40 MW / purchased 60 Hz electric power

[0131] "Catacarb" compressor; 10 MW

[0132] Accessories and utilities; 3 MW

[0133] Excess power / power margin 50 Hz: 24 mW.

[0134] Purchased external power: 83 MW, estimated price of 4 cents / kwh; 3320 $ / h

[0135] We refer to ​ : (1) is the conversion gas turbine that constitutes the starting point of the invention. ( '4') : is the cooling line from the compressor (2) to the expander (3) that is now unnecessary, also not replaced by the gas from number 6, as the expander (3) is sensitive to contaminants. The cooling requirement of the expander (3) usually requires 5% of the total of the compressor (2), but now all goes to C02 capture. This brings a 5% improvement.

[0136] Parts list:

[0137]

[0138]

[0139]

Claims

1. A CO2 capture system comprising the following features: - a CO2 rich exhaust gas (6g) from a first source (6s) to an inlet (6) of a compressor (2); and a first CO2 rich gas (6r) compressed at a pressure (P) to a first manifold (8), to a housing (10) enclosing at least part of a combustion chamber (11) having a wall (1 1w), - wherein compressed air (15c) is introduced only to a burner (13) without mixing with the first CO2 rich gas (6r) from the compressor (2), - wherein the combustion chamber (11) comprises the burner (13) arranged to combust fuel (14f) and compressed air (15c) supplied from a fuel line (14) and a compressed air line (15), respectively, at the pressure (P) to form a second CO2 rich gas (15r) in the burner (13), - wherein a slit (12) is provided in the wall (1 1w) in the combustion chamber (11) for the compressed first CO2 rich gas (6r) to enter to mix with the second CO2 rich gas (15r) formed in the burner (13) and to cool to a third CO2 rich gas (60r); - a heat exchanger (16) arranged to operate at the pressure (P) and to exchange heat from the hot third CO2 rich gas (60r) from the combustion chamber (11) and flowing out from the combustion chamber via a pipe (17) to a CO2 extraction device with a returned CO2 lean gas (60L) from the CO2 extraction device at the pressure (P) via a line (18), - wherein the returned, now heated, CO2 lean gas (60L) is guided via a second manifold (9) back to a turbogenerator (3) and via a second outlet to be discharged, the turbogenerator driving the compressor (2) and the CO2 extraction device.

2. The CO2 capture system according to claim 1, further comprising a regulation system arranged to regulate the supply of compressed air (15c) and fuel (14f) to be substantially equal to the amount of CO2 extracted in the CO2 extraction device, so that the amount of gas flowing over the turbogenerator (3) corresponds to the amount of gas flowing in by the compressor (2).

3. The CO2 capture system of claim 1 or 2, wherein, The compressor, first and second manifolds (8, 9), the combustion chamber (11), the heat exchanger (16), the CO2 extraction device and the turbogenerator (3) are adapted to a pressure (P) in the first, second and third CO2 rich gases (6r, 15r, 60r) and the resulting CO2 lean gas (60L) being higher than 12 bar.

4. The CO2 capture system of claim 1 or 2, wherein, The compressor, first and second manifolds (8, 9), the combustion chamber (11), the heat exchanger (16), the CO2 extraction device and the turbogenerator (3) are adapted to a pressure (P) in the first, second and third CO2 rich gases (6r, 15r, 60r) and the resulting CO2 lean gas (60L) being higher than 16 bar.

5. The CO2 capture system of claim 1 or 2, wherein, The compressor, the first and second manifolds (8, 9), the combustion chamber (11), the heat exchanger (16), the CO2 extraction device and the expander (3) are adapted to pressures (P) in the first, second and third CO2 rich gases (6r, 15r, 60r) and the resulting CO2 lean gas (60L) higher than 19 bar.

6. The CO2 capture system of claim 1 or 2, wherein, The CO2 extraction device is a so-called hot potassium carbonate K2CO3 device, the extraction device comprising an absorption column (21) operating at the pressure (P) and arranged for operation with an absorption medium comprising a mixture of water and potassium carbonate K2CO3, wherein the reaction in the absorption column (21) is: CO2 + K2CO3 + H2O = 2 KHCO3 + heat.

7. The CO2 capture system according to claim 1 or 2, - wherein a generator / starting motor (G) is connected to the compressor (2) and the expander (3), and wherein the generator / starting motor (G) is arranged to generate energy recovered in the expander (3) to drive the processes in the compressor (2), the CO2 extraction device and the CO2 capture system as a whole.

8. The CO2 capture system of claim 7, wherein, The compressor and the expander are on a common shaft.

9. The CO2 capture system according to claim 7, the compressor and the expander are further on the cold side of the inlet (6).

10. The CO2 capture system according to claim 7, - wherein a generator / starter motor (G) is arranged to pressurize the CO2 capture system prior to start-up, and wherein, The energy of the generator / starting motor (G) is externally obtained.

11. The CO2 capture system according to claim 7, - wherein a generator / starter motor (G) is arranged to pressurize the CO2 capture system prior to starting, and wherein, The energy of the generator / starting motor (G) is obtained from the grid.

12. The CO2 capture system according to claim 7, - wherein a generator / starter motor (G) is arranged to pressurize the CO2 capture system prior to starting, and wherein, The energy of the generator / starting motor (G) is obtained from a generator of a thermal power plant, the thermal power plant further producing the first source (6s).

13. The CO2 capture system according to claim 1 or 2, - wherein the combustion chamber (11) is a silo combustion chamber.

14. The CO2 capture system according to claim 1 or 2, - wherein, The first and second manifolds (8, 9) are annular manifolds arranged around a casing (19) and connected to the first outlet (5) from the compressor (2) and to the return to the expander (3).

15. The CO2 capture system according to claim 1 or 2, - wherein, The first outlet (5) from the compressor (2) is a coaxial outlet around a return pipe of the casing (19) between the compressor (2) and the expander (3).

16. The CO2 capture system according to claim 1 or 2, - wherein a compressed air line (15) is guided through a cooling casing on the heat exchanger (16), the cooling casing being arranged to cool a pressure shell of the heat exchanger (16), the heat exchanger (16) preheating the compressed air (15c) before injection at the top of the combustion chamber (11).

17. The CO2 capture system according to claim 1 or 2, - wherein the lower part of the combustion chamber (11) in the housing (10) is internally clad with ceramic tiles for shielding against radiant heat from the combustion process of fuel (14f) and compressed air (15c) at the burner (13).

18. A CO2 capture method using a CO2 capture system comprising the steps of: - compressing a first CO2 rich gas (6g) from a first source (6s) by a compressor (2) and forming a compressed first CO2 rich gas (6r), - burning fuel (14f) by a burner (13) with compressed air (15c), the burner (13) being arranged at the top of a combustion chamber (11) and forming a second CO2 rich gas (15r) at a pressure (P), - passing the compressed first CO2 rich gas (6r) through a slit in the burner wall (11w) into the combustion chamber (11) and mixing into and cooling the second CO2 rich gas (15r) to form a resulting pressurized third CO2 rich gas (60r); - the pressurized third CO2 rich gas (60r) is discharged through a heat exchanger (16) which exchanges the hotter third CO2 rich gas (60r) with a cooler returning pressurized CO2 lean gas (60L) from a CO2 extraction plant, - wherein the cooled, third CO2 rich gas (60r) is passed from the heat exchanger (16) through a conduit (17) into the CO2 extraction plant and wherein the resulting cooler CO2 lean gas (60L) is returned under pressure through a line (18) to the heat exchanger (16) and heated by the heat exchanger, - wherein the returning heated CO2 lean gas (60L) is expanded by an expander (3).

19. The CO2 capture method of claim 18, wherein, The supply of compressed air (15c) and fuel (14f) is equally adjusted with respect to the amount of CO2 extracted in the CO2 extraction plant so that the amount of gas flowing over the expander (3) corresponds to the amount of gas flowing in by the compressor (2).

20. The CO2 capture method according to claim 18 or 19, wherein, The pressure in the first CO2 rich gas (6r), the second CO2 rich gas (15r), the third CO2 rich gas (60r) and the CO2 lean gas (60L) in the method is higher than 12 bar.

21. The CO2 capture method of claim 18 or 19, wherein, The pressure in the first CO2 rich gas (6r), the second CO2 rich gas (15r), the third CO2 rich gas (60r) and the CO2 lean gas (60L) in the method is higher than 16 bar.

22. The CO2 capture method of claim 18 or 19, wherein, The pressure in the first CO2 rich gas (6r), the second CO2 rich gas (15r), the third CO2 rich gas (60r) and the CO2 lean gas (60L) in the method is higher than 19 bar.

23. The CO2 capture method according to claim 18 or 19, wherein, In the CO2 extraction plant an absorption column (21) with an absorption medium is used, the so-called Hot Potassium Carbonate (HPC) process, the absorption medium comprising a mixture of water and potassium carbonate K2CO3, - wherein the reaction in the absorption column (21) is: CO2 + K2CO3 + H2O = 2 KHCO3 + heat.

24. The CO2 capture method of claim 18 or 19, wherein, The CO2 extraction device operates at a third CO2 rich gas (60r) and CO2 lean gas (60L) gas pressure, wherein the third CO2 rich gas (60r) and CO2 lean gas (60L) gas pressure corresponds to the gas pressure in the compressor (2), combustion chamber (11) and heat exchanger (16), and further back to the expander (3).

25. The CO2 capture method according to claim 18 or 19, wherein, A generator / start motor (G) is connected to the compressor (2) and the expander (3), and wherein the generator / start motor (G) generates energy recovered in the expander (3) to drive the processes in the compressor (2), the CO2 extraction device and the system in total.

26. The CO2 capture method of claim 25, wherein, The compressor (2) and the expander (3) are mounted on a common shaft.

27. The CO2 capture method of claim 25, wherein, The compressor (2) and the expander (3) are mounted on the cold side at the inlet (6).

28. The CO2 capture method of claim 25, wherein, A generator / start motor (G) pressurizes the system before start-up, and wherein the energy of the generator / start motor (G) is externally acquired.

29. The CO2 capture method of claim 25, wherein, A generator / start motor (G) pressurizes the system before start-up, and wherein the energy of the generator / start motor (G) is acquired from the grid.

30. The CO2 capture method of claim 25, wherein, A generator / start motor (G) pressurizes the system before start-up, and wherein the energy of the generator / start motor (G) is acquired from a power plant generating the first source (6s).

31. The CO2 capture method according to claim 18 or 19, - wherein the first source (6s) is an external gas turbine, which supplies a CO2 rich exhaust gas (6g).

32. The CO2 capture method according to claim 18 or 19, - wherein, The first source (6s) is a coal fired thermal power plant or a cement plant, a refinery cracker or a waste incineration plant, which supplies a CO2 rich exhaust gas (6g).

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