LU103035B1 - Energy-efficient carbon dioxide capture, especially for a cement plant - Google Patents

Abstract

The present invention relates to a device for treating a mineral material, wherein the device has at least one preheater 11, a treatment device 12, 13 and a material cooler 14, wherein the device has a carbon dioxide separation device 32, wherein the carbon dioxide separation device 32 has a carbon dioxide compressor 31, wherein the carbon dioxide compressor 31 is connected to a first turbine 30, wherein the first turbine 30 is designed to drive the carbon dioxide compressor 31, wherein the material cooler 14 has a cooler gas outlet 81, wherein the device has a first heat exchanger 20, wherein the first heat exchanger 20 has a first gas side and a first heat exchange medium side, wherein the cooler gas outlet 81 is connected to the first gas side of the first heat exchanger 20, wherein the first heat exchange medium side of the first heat exchanger 20 is connected to the first turbine 30 via a first heat exchange circuit.

Description

thyssenkrupp Industrial Solutions AG 221483P00LU thyssenkrupp AG 14.11.2022 LU103035 1/9

Energy-efficient carbon dioxide capture, especially for a cement plant

The invention relates to a device and a method for energy-efficient

Separation of carbon dioxide, especially in clinker production.

The prevention of carbon dioxide emissions is becoming increasingly important. Therefore, corresponding plants, for example in the cement industry, are increasingly being equipped in such a way that carbon dioxide is separated, either for further separate use or for final storage.

Oxygen-enriched combustion in an industrial process is known from US 2009 / 0308073 A1.

WO2011/082193A1 describes an integrated material cooler and

Heat recovery is known.

From CN 112393597 A a cement burning system with a process for

Combustion with pure oxygen is known.

EP1338848A discloses a method and a device for integrated

Air separation and heat recovery in a furnace.

From US 8 236 093 B2 an emission control of a power plant using an Organic Rankine Cycle is known.

EP2167 794 B1 discloses a device and a method for force

Heat generation is known.

An integrated process for oxyfuel combustion and oxygen production is known from CN 105980776 A.

From KR 2162987 B1 a method for separating and storing

Carbon dioxide from exhaust gases in cement production is known.

thyssenkrupp Industrial Solutions AG 221483P00LU thyssenkrupp AG 14.11.2022 LU103035 2/9

For example, downstream devices are integrated to separate carbon dioxide from the exhaust gas. Other processes, such as the oxyfuel process, attempt to produce the purest carbon dioxide possible within the process by using oxygen that is as pure as possible instead of air (especially without

Nitrogen). Regardless of the type of separation and/or recovery of the

Carbon dioxide must be compressed regularly after separation in order to be able to be transported or used further. This compression creates a new energy requirement.

One challenge here is that the increasing complexity creates additional energy requirements. The aim is therefore to no longer just optimize individual processes, but to abandon traditional solutions, for example for the production of clinker, and to develop new concepts in order to work in a holistic, energy-optimized manner.

The object of the invention is to provide a method and a device to be particularly efficient throughout the entire process.

This object is achieved by the device with the features specified in claim 1

Features and by the method having the features specified in claim 8.

Advantageous further developments result from the subclaims, the following

Description and drawing.

The device according to the invention serves to treat a mineral material.

For example and preferably, it is a device for producing

Cement clinker. The device comprises at least one preheater, a

treatment device and a material cooler. For example and in particular, a second treatment device can also be provided. For example and preferably, the first treatment device is a calciner and the second

Treatment device is a furnace, in particular a rotary kiln. The device has a carbon dioxide separation device. Carbon dioxide separation device is to be understood broadly in the sense of the invention. On the one hand, the thyssenkrupp Industrial Solutions AG 221483P00LU thyssenkrupp AG 14.11.2022 LU103035 3/9

Carbon dioxide separation device classic devices for the separation of

Carbon dioxide from an exhaust gas stream, for example by means of an amine solution or the

Carbonate looping process. Cryogenic processes can also be used to

separation. If, however, the device is used, for example, after the

If you use the oxyfuel process, i.e. use oxygen instead of air, then theoretically quite pure carbon dioxide is produced, but mostly contaminated with water and dust, and sometimes with other organic components. In such a case, the carbon dioxide separation device is designed much more simply. The

Carbon dioxide separation device can also be designed to adjust the purity of the carbon dioxide produced. The carbon dioxide separation device has a carbon dioxide compressor. For most applications, a

Compression of carbon dioxide is necessary, for example for storage and

Transport is advantageous. For high compressions, a two-stage compression can also be used. The second compression can also be carried out separately from the one described here, separated in time and/or space. The carbon dioxide compressor is equipped with a first

Turbine. The first turbine is designed to drive the carbon dioxide compressor. The material cooler has a cooler gas outlet. The device has a first heat exchanger. The first heat exchanger has a first gas side and a first heat exchange medium side. The cooler gas outlet is connected to the first

Gas side of the first heat exchanger. Thus, the heat transferred to the

The gas stream flowing through the material cooler is heated there, led through the cooler gas outlet into the first heat exchanger and releases the heat there to a heat exchange medium, for example steam. The first heat exchange medium side of the first

The heat exchanger is connected to the first turbine via a first heat exchange circuit. The heat exchange medium drives the turbine and thus the

carbon dioxide compressor. The heat from the material cooler is therefore not transferred to the

process, but is used to compress the separated carbon dioxide. This means that, for example, an electrical energy supply for the

Compression of carbon dioxide can be avoided.

In a further embodiment of the invention, the first heat exchange circuit is a

Steam cycle. The heat exchange medium is therefore water. At the comparatively high temperature level, preferably above 400°C,

Water vapor is a particularly suitable medium.

In a further embodiment of the invention, the preheater has a

preheater gas outlet. The device comprises a second heat exchanger. The second heat exchanger comprises a second gas side and a second

The preheater gas outlet is connected to the second gas side of the second heat exchanger. This also allows the heat from the

gas stream leaving the preheater.

In a further embodiment of the invention, the device comprises a system for

Air separation is required, for example, if the device is operated using the oxyfuel process, i.e. with enriched or technically pure oxygen, which makes the separation of carbon dioxide at the end much easier, since the exhaust gas contains no or very little

Nitrogen. The air separation has an air compressor. For the

Air separation usually requires increased pressure. The air compressor is connected to a second turbine. The second turbine is used to drive the

air compressor. The second turbine is connected to the first

Heat exchange medium side of the first heat exchanger About a first

Heat exchange circuit or with the second heat exchange medium side of the second

Heat exchanger via a second heat exchange circuit. Preferably, the second turbine is connected to the second heat exchange medium side of the second heat exchanger via a second heat exchange circuit. The lower energy level is typically sufficient, and when the system is started up, the

Air separation is required immediately and the waste heat from the preheater is available early

available even before solid material is passed through the device. Therefore, this

Arrangement particularly advantageous.

In a further embodiment of the invention, the second heat exchange circuit is a

Organic Rankine Cycle. Here, a different heat carrier is used instead of water to build up sufficient pressure to operate the turbine even at lower temperatures. Examples are ammonia, butane and pentane. The much lower boiling point of these compounds is exploited here.

In a further embodiment of the invention, the first heat exchange circuit is connected to a generator in addition to the first turbine. In this way, additional electricity can be generated, in particular to cover the energy requirements, for example in air separation or carbon dioxide capture. Preferably, the

Generator can be separated, for example via valves. This allows the

Generator should only be switched on if there is surplus energy to

Electricity generation is available.

In a further embodiment of the invention, the

Carbon dioxide separation device has an absorber stage and/or a cleaning stage. As already mentioned, the carbon dioxide content of the exhaust gas varies greatly.

In most cases, water and volatile compounds must be separated, and in many cases nitrogen must also be removed. Therefore, it can be advantageous to

Carbon dioxide selectively with an absorber stage, for example an amine or after the

Carbonate looping process to selectively wash out the exhaust gas. If the exhaust gas is already very rich in carbon dioxide, for example in the oxyfuel process, a

Cleaning stage, for example for the separation of water and organic

components are sufficient. The exhaust gas can also be processed in a cryogenic plant.

In a further aspect, the invention relates to a method for operating a device according to the invention. The method is characterized in that the

The gas heated by the material cooler is fed to the first heat exchanger to at least 95%. The point is that the heat does not enter the treatment device in

The carbon dioxide is not transferred to the form of preheated air, but is used to compress the carbon dioxide. This is unfavourable for the actual thermal treatment process and therefore initially appears to be disadvantageous in terms of energy. However, it has been shown that in combination with the carbon dioxide separation this is ultimately advantageous.

thyssenkrupp Industrial Solutions AG 221483P00LU thyssenkrupp AG 14.11.2022 LU103035 6/9

In a further embodiment of the invention, enriched oxygen is fed directly from an air separation unit to the treatment device. The oxygen is thus not preheated or only very slightly preheated. However, it has been shown that in this case

Constellation by combustion in (relatively) pure oxygen the

The heat of combustion is so high that the supply of cold oxygen is possible and thus the use of the heat of the product for the compression of the carbon dioxide is possible and advantageous.

In a further embodiment of the invention, the material cooler is provided by the

The gas leaving the cooler gas outlet has a maximum temperature of 400 °C. This distinguishes the process from processes in which the highest heat is used to preheat the air supplied to the treatment device to the maximum and thus only gas at a very low temperature level is available for other processes.

makes available.

In a further aspect, the invention relates to a method for operating a device according to the invention. The method is characterized in that the

The gas heated by the material cooler is fed to the first heat exchanger at 30% to 70%. The gas leaving the material cooler through the cooler gas outlet has a

Temperature of at least 400 °C, preferably at least 600 °C, particularly preferably at least 750 °C. This distinguishes this process from

Processes in which the highest heat is used to

The aim is to preheat the air supplied to the treatment device to the maximum and thus only make gas available at a very low temperature level for other processes. The point is that the heat is not transferred to the treatment device in the form of preheated air, but is used to compress the carbon dioxide. This is unfavorable for the actual thermal treatment process and therefore initially appears to be energetically disadvantageous. However, it has been shown that in

In combination with carbon dioxide separation, this is ultimately advantageous.

The device according to the invention is explained in more detail below using an embodiment shown in the drawing.

thyssenkrupp Industrial Solutions AG 221483P00LU thyssenkrupp AG 14.11.2022 LU103035 7/9

Fig. 1 exemplary device

An exemplary device is shown in Fig. 1. The device has three primary

Material flows are shown, which are used to illustrate the device and thus also the process in a very simplified manner.

Mineral material to be thermally treated, for example ground limestone, is fed to the device via the material inflow 70, heated in a preheater 11 and then processed in a calciner 12 (as the first treatment device) and a kiln 13 (as the second treatment device). The finished product, for example the fully fired clinker, leaves the device via the material outflow 71.

In order to cool the finished product in the material cooler 14, the material cooler 14 is provided with a

Gas flow is fed via the gas supply 80. Heated, the gas flow leaves the

Material cooler 14 via the cooler gas outlet 81 and is led into the first heat exchanger. There, the heat is transferred to a first heat exchange medium, preferably steam. The cooled gas stream leaves the device via the

Gas discharge 82. The steam generated in the first heat exchanger 20 is discharged to a first

Turbine 30 and a third turbine 60 and drives them. The third turbine 60 drives a generator 61 so that electricity can be generated. The first turbine 30 drives the carbon dioxide compressor 31.

The third material flow described is the gas flow passed through the treatment device. Air is fed to an air compressor 50 via an air supply 90.

The compressed air is then fed to an air separation unit 51 and separated into nitrogen and

Oxygen separated (in a first approximation, impurities in technical

degrees of purity are ignored here for simplicity). The nitrogen is

Nitrogen discharge 91 is released again, the oxygen is fed to the furnace 13 via the oxygen line 92 directly and without preheating in the material cooler 14. In the furnace 13, combustion takes place to generate energy. Due to the comparatively high

Due to the high energy release during combustion in pure oxygen, preheating is easily dispensable. The gas stream is then fed from the furnace 13 into the calciner 12, where a second combustion usually takes place to generate energy. After this, the gas stream preferably consists of more than 90% carbon dioxide (based on dry

Gas, i.e. without water). For example, the oxygen content is less than 2-4%. This facilitates the subsequent separation of carbon dioxide from the exhaust gas. The hot

Gas flow is led from the calciner 12 into the preheater 11 and there transfers most of the heat to the reactant, for example limestone. The gas flow leaves the preheater 11 at, for example, 200 to 250 °C and is fed into a second

heat exchanger 40. The second heat exchanger 40

The heat exchange cycle is an Organic Rankine Cycle. Butane, for example, is used as a heat exchange medium. This enables the use of the comparatively low temperatures to drive the second turbine 41, which in turn drives the

The advantage is that during start-up, before the introduction of reactant and thus before heat is introduced into the material cooler 14, the second

Heat exchanger 40 is already operating the air separation 51, which produces the oxygen for the

The gas flow is fed after the second heat exchanger 40 into the

Carbon dioxide separation device 32 and is divided there into a carbon dioxide stream and an exhaust gas stream. The exhaust gas stream may contain residues of carbon dioxide and can be released into the environment as exhaust gas 93, for example. The

Carbon dioxide stream is fed into the carbon dioxide compressor 31 and compressed there and then discharged via the carbon dioxide discharge 94. The

Carbon dioxide compressor 31 is, as stated above, driven by the first turbine 30 and thus with the waste heat from the material cooler 14.

Reference numerals 11 Preheater 12 Calciner 13 Furnace 14 Material cooler 20 First heat exchanger First turbine 30 31 Carbon dioxide compressor 32 Carbon dioxide separation device Second heat exchanger 41 Second turbine thyssenkrupp Industrial Solutions AG 221483P00LU thyssenkrupp AG 14.11.2022 LU103035 9/9 50 Air compressor 51 Air separation 60 Third turbine 61 Generator 70 Material inflow

71 Material drain 80 Gas supply 81 Cooler gas outlet 82 Gas discharge

90 Air supply 91 Nitrogen discharge 92 Oxygen line 93 Exhaust gas 94 Carbon dioxide discharge

Claims (11)

thyssenkrupp Industrial Solutions AG 221483P00LU thyssenkrupp AG 14.11.2022 LU103035 1/2 Patent claims 1. Device for treating a mineral material, the device comprising at least one preheater (11), a treatment device (12, 13) and a material cooler (14), the device comprising a carbon dioxide separation device (32), the carbon dioxide separation device (32) comprising a carbon dioxide compressor (31), the carbon dioxide compressor (31) being connected to a first turbine (30), the first turbine (30) being designed to drive the carbon dioxide compressor (31), the material cooler (14) comprising a cooler gas outlet (81), the device comprising a first heat exchanger (20), the first heat exchanger (20) having a first gas side and a first heat exchange medium side, the cooler gas outlet (81) being connected to the first gas side of the first heat exchanger (20), the first heat exchange medium side of the first heat exchanger (20) being connected to the first turbine (30) via a first heat exchange circuit. 2. Device according to claim 1, characterized in that the first heat exchange circuit is a water vapor circuit. 3. Device according to one of the preceding claims, characterized in that the preheater (11) has a preheater gas outlet, the device comprising a second heat exchanger (40), the second heat exchanger (40) having a second gas side and a second heat exchange medium side, the preheater gas outlet being connected to the second gas side of the second heat exchanger (40). 4. Device according to one of the preceding claims, characterized in that the device has an air separation (51), wherein the air separation (51) has an air compressor (50), wherein the air compressor (50) is connected to a second turbine (41), wherein the second turbine (41) is designed to drive the air compressor (50), wherein the second turbine (41) is connected to the first heat exchange medium side of the first heat exchanger (20) via a thyssenkrupp Industrial Solutions AG 221483P00LU thyssenkrupp AG 14.11.2022 LU103035 2/2 first heat exchange circuit or to the second heat exchange medium side of the second heat exchanger (40) via a second heat exchange circuit. 5. Device according to one of claims 3 to 4, characterized in that the second heat exchange circuit is an Organic Rankine Cycle. 6. Device according to one of the preceding claims, characterized in that the first heat exchange circuit is connected to a generator (61). 7. Device according to one of the preceding claims, characterized in that the carbon dioxide separation device (32) has an absorber stage and/or a cleaning stage. 8. Method for operating a device according to one of the preceding claims, characterized in that the gas heated in the material cooler (14) is fed to at least 95% to the first heat exchanger (20). 9. Method according to claim 8, characterized in that enriched oxygen is supplied to the treatment device (12, 13) directly from an air separation. 10. Method according to one of claims 8 to 9, characterized in that the gas leaving the material cooler (14) through the cooler gas outlet (81) has a temperature of less than 400 °C. 11. Method for operating a device according to one of claims 1 to 7, characterized in that the gas heated in the material cooler (14) is fed to 70% to the first heat exchanger (20), wherein the gas leaving the material cooler (14) through the cooler gas outlet (81) has a temperature of at least 400 °C, preferably of at least 600 °C, particularly preferably of at least 750 °C.