(19)
(11)EP 2 544 998 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
05.08.2020 Bulletin 2020/32

(21)Application number: 11715029.2

(22)Date of filing:  01.03.2011
(51)Int. Cl.: 
C01B 32/50  (2017.01)
B01D 53/86  (2006.01)
(86)International application number:
PCT/IB2011/000423
(87)International publication number:
WO 2011/110915 (15.09.2011 Gazette  2011/37)

(54)

SYSTEM AND METHOD FOR GENERATING A CARBON DIOXIDE STREAM

SYSTEM UND VERFAHREN ZUR ERZEUGUNG EINES KOHLENDIOXIDSTROMES

SYSTÈME ET PROCÉDÉ POUR GÉNÉRER UN COURANT DE DIOXYDE DE CARBONE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 11.03.2010 US 721638

(43)Date of publication of application:
16.01.2013 Bulletin 2013/03

(73)Proprietor: General Electric Technology GmbH
5400 Baden (CH)

(72)Inventors:
  • BIALKOWSKI, Michal, Tadeusz
    CH-5417 Untersiggenthal (CH)
  • KAEFER, Gisbert, Wolfgang
    CH-5413 Birmenstorf (CH)

(74)Representative: BRP Renaud & Partner mbB Rechtsanwälte Patentanwälte Steuerberater 
Königstraße 28
70173 Stuttgart
70173 Stuttgart (DE)


(56)References cited: : 
EP-A2- 0 469 781
US-A- 4 364 915
WO-A1-03/070635
  
  • DUESO C ET AL: "Syngas combustion in a chemical-looping combustion system using an impregnated Ni-based oxygen carrier", FUEL, IPC SCIENCE AND TECHNOLOGY PRESS, GUILDFORD, GB, vol. 88, no. 12, 1 December 2009 (2009-12-01), pages 2357-2364, XP026587333, ISSN: 0016-2361, DOI: 10.1016/J.FUEL.2008.11.026 [retrieved on 2008-12-12]
  • HOSSAIN M M ET AL: "Chemical-looping combustion (CLC) for inherent CO2 separations-a review", CHEMICAL ENGINEERING SCIENCE, OXFORD, GB, vol. 63, no. 18, 1 September 2008 (2008-09-01), pages 4433-4451, XP025467861, ISSN: 0009-2509, DOI: 10.1016/J.CES.2008.05.028 [retrieved on 2008-05-29]
  
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description

BACKGROUND


1. Field



[0001] The present disclosure generally relates to a system and method for generating a carbon dioxide stream. More particularly, the present disclosure relates to generating a carbon dioxide stream in a flue gas stream processing system employing a chemical looping combustion system.

2. Related Art



[0002] Chemical looping combustion (CLC) is a combustion technology that affords inherent separation of carbon dioxide (CO2), as, e.g., described in the article "Syngas combustion in a chemical-looping combustion system using an impregnated Ni-based oxygen carrier" by Cristina Duesco et al. in Fuel, IPC Science and Technology Press, Guildford, GB, vol. 88, no. 12, 1 December 2009, pages 2357-2364, DOI: 10.1016/J.FUEL.2008.11.026; or in "Chemical-looping combustion (CLC) for inherent CO2 separations-a review" by Mohammad M. Hossain et al. in Chemical Engineering Science, Oxford, GB, vol. 63, no. 18, 1 September 2008, pages 4433-4451, DOI: 10.1016/J.CES.2008.05.028. Typically, CLC employs two reactors: an air reactor and a fuel reactor. A solid oxygen carrier, which may be a metal, transfers the oxygen from the air to the fuel. The fuel is fed to the fuel reactor where it is oxidized by the oxygen carrier and the oxygen is carrier is reduced and retuned to the air reactor, where it is oxidized and the loop of oxidizing the fuel and reducing the carrier continues. The exit stream from the fuel reactor, commonly referred to as the flue gas, typically contains CO2 and water vapor. However, depending on the fuel, the flue gas may also contain trace contaminants, as described, e.g. in EP 0 469 781 A2, related to separation of carbon dioxide and nitrogen from combustion exhaust gas with nitrogen and argon byproduct recovery. The water vapor in the flue gas is separated from the CO2 by cooling and condensation, while the CO2 is liquefied or compressed for further transport.

[0003] Due to its limited residence time in the fuel reactor and the lack of free oxygen, the CO2 stream may be contaminated with products of incomplete combustion, such as carbon monoxide (CO), hydrogen (H2), and methane (CH4). Additionally, the flue gas stream may be diluted with air, which may in-leak to the boiler.

[0004] Contaminants such as CO, H2, and CH4 are more difficult to liquefy than CO2 during liquification of the CO2. The contaminants take the form of a non-condensable phase commonly referred to as a exhaust gas. The level of contaminates within the exhaust gas as is often too high to be released to the atmosphere without further treatment. Recycling of the exhaust gas to the fuel reactor would result in gradual accumulation of N2 and other inert gases in the flue gas and may also dilute the CO2 stream, thereby reducing the efficiency of the CLC system.

[0005] WO 03/070635 A1 describes a method for removing contaminants from gases, in which carbon dioxide is purified through the use of catalytic oxidation, wherein carbon dioxide is exposed to at least one catalyst, oxidizing at least a portion of the nonvolatile organic residues to form purified carbon dioxide that is directed to an application. Carbon dioxide that is in a near-critical, critical, or supercritical phase can be exposed to the catalyst.

[0006] US 4,364,915 A describes a process for recovery of carbon dioxide from a flue gas stream containing residual oxygen wherein a combustible fuel, such as methane, is admixed with the flue gas stream and the flue gas stream is then passed into a combustion zone in which it may be contacted with a catalyst which promotes the consumption of the residual oxygen in a combustion reaction.

[0007] Accordingly, a method or system for processing the exhaust gas in an efficient way without impacting the CLC system is desired.

SUMMARY



[0008] According to aspects illustrated herein, there is provided a method of generating a liquefied carbon dioxide stream, the method comprising: generating a flue gas stream including carbon monoxide and water vapor by a chemical looping combustion system; subjecting the flue gas stream to an oxidation catalyst for oxidizing the carbon monoxide, thereby generating a carbon dioxide rich flue gas stream; and processing the carbon dioxide rich flue gas stream to form a liquefied carbon dioxide stream; returning at least a part of the exhaust gas to an air reactor of a chemical looping combustion system, if the carbon monoxide present in the flue gas stream is less than one percent by volume of the carbon dioxide concentration in the flue gas stream.

[0009] According to other aspects illustrated herein, there is provided a method for reducing an amount of contaminants released by a flue gas stream processing system, the method comprising: generating a flue gas stream by combustion of a fuel in a fuel reactor of a chemical looping combustion system, the flue gas stream includes water vapor and carbon monoxide; forming a liquefied carbon dioxide stream by removing water vapor and carbon monoxide from the flue gas stream; generating an exhaust gas during formation of the liquefied carbon dioxide stream; and providing at least a portion of the exhaust gas to an air reactor in the chemical looping combustion system, thereby reducing an amount of contaminants released by a flue gas stream processing system.

[0010] The above described and other features are exemplified by the following figures and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS



[0011] Referring now to the figures, which are exemplary embodiments, and wherein the like elements are number alike:

FIGURE 1 is a schematic block diagram of one embodiment of the system disclosed herein; and

FIGURE 2 is a schematic block diagram of one embodiment of the system disclosed herein.


DETAILED DESCRIPTION



[0012] FIG. 1 illustrates a flue gas stream processing system 100 having a combustion system 120. The combustion system 120 may be any system capable of combusting a fuel 122 to form a flue gas 124. The combustion system 120 illustrated in FIG. 1 is a chemical looping combustion system that includes an air reactor 126 and a fuel reactor 128. The flue gas stream processing system 100 is not limited in this regard since the combustion system 120 may be other combustion systems, including, but not limited to boilers, furnaces, and the like.

[0013] In operation, the chemical looping combustion system 120 includes an oxygen carrier 130, which transfers oxygen from the air present in the air reactor 126 to the fuel 122 provided to the fuel reactor 128. The fuel 122 is oxidized by the oxygen carrier 130 in the fuel reactor 128 and the oxygen carrier is reduced and returned to the air reactor 126 as a reduced oxygen carrier 132. The reduced oxygen carrier 132 is oxidized in the air reactor 126 and the loop of oxidizing the fuel 122 and reducing the oxygen carrier 130 continues. The oxygen carrier 130 may be a metal, such as, but not limited to nickel, copper, iron, manganese, cadmium, and cobalt.

[0014] As shown in FIG. 1, the chemical loop combustion system 120 may include one or more cyclones 134, which facilitate the separation of the oxygen carrier 130 from depleted air and separation of the flue gas stream 124 from the reduced oxygen carrier 132.

[0015] Oxidation of the fuel 122 in the fuel reactor 128 produces the flue gas stream 124, a portion of which may be recycled to the fuel reactor 128. The flue gas stream 124 typically contains carbon monoxide (CO) carbon dioxide (CO2) and water vapor. However, depending on the fuel, the flue gas stream 124 may also contain varying concentrations of trace contaminants, such as, but not limited to sulfur oxides (SOx), nitrogen oxides (NOx), mercury, hydrogen (H2), and methane (CH4). The flue gas stream 124 may also include contaminants such as fly ash as well as unburnt fuel (referred to as "unburnts").

[0016] The oxygen required for the oxidationof the carbon monoxide can be introduced by an air stream 152 that leaks into a boiler 154, through which the flue gas stream 124 passes. Oxidation of carbon monoxide forms carbon dioxide, which can be condensed and liquefied in the processing unit 150. The leakage of air stream 152 into the boiler 154 is typically about 2% of the volume flue of the flue gas stream 124.

[0017] Removal of the contaminants present in the flue gas stream 124 may be conducted by providing the flue gas stream to a contaminant removal system 140 prior to introduction to a processing unit 150. Examples of contaminant removal systems 140 include, but are not limited to, particle removable devices, desulfurization systems such as wet flue gas desulfurization (WFGD) or dry flue gas desulfurization (DFGD), nitrogen oxide (NOx) removal systems, mercury removal systems (e.g., activated carbon), and the like, and combinations thereof. Removal of at least a portion of the contaminants from the flue gas stream 124 produces a carbon dioxide rich flue gas stream 124', which is introduced to the processing unit 150.

[0018] The processing unit 150 condenses and liquefies the carbon dioxide present in the carbon dioxide rich flue gas stream 124', while removing any remaining contaminants to produce a carbon dioxide stream 156 and an exhaust gas 158. The carbon dioxide stream 156 is transported in liquefied form to another location for compression, use and/or storage.

[0019] The exhaust gas 158 typically contains material that was not removed from the flue gas stream 124, such as nitrogen, hydrogen, oxygen and carbon monoxide.

[0020] In one embodiment, as shown in FIG. 1, if the carbon monoxide present in the flue gas stream 124 is less than about one percent by volume (1% by vol.) of the carbon dioxide concentration in the flue gas stream, at least a portion of the exhaust gas 158 may be returned to the air reactor 126.

[0021] Measurement of the carbon monoxide concentration in the flue gas stream 124 may be obtained by a measuring device 160. The measuring device 160 may be any device capable of obtaining measurements of a carbon monoxide concentration. Examples of the measuring device 160 include, but are not limited to a sensor or a combustion gas analyzer, e.g., a Fyrite® analyzer. The measuring device 160 may be coupled to a controller 170, e.g., a data processor, capable of accepting operating instructions 172 from a user and provide the user with data 174 concerning the measured concentration.

[0022] In another embodiment, as illustrated in FIG. 2, if the concentration of the carbon monoxide present in the flue gas stream 124 is about one percent by volume (1% by vol.) or greater than the carbon dioxide concentration in the flue gas stream 124, the exhaust gas 158 is not returned to the air reactor 126 and is instead provided to the atmosphere. Additionally, the carbon dioxide rich flue gas stream 124' is subjected to further processing prior to introduction to the processing unit 150. Specifically, an oxidation catalyst 180 is placed downstream from the fuel reactor 128 at a location between the contaminant removal system 140 and the processing unit 150. The oxidation catalyst 180 facilitates the oxidation of carbon monoxide present in the carbon dioxide rich flue gas stream 124' to form carbon dioxide.

[0023] The oxidation catalyst 180 works in conjunction with the air stream 152 to oxidize the carbon monoxide present in the flue gas stream. If the carbon monoxide concentration in the flue gas stream 124 is less than about 3% by volume of the carbon dioxide concentration in the flue gas stream, the air stream 152 that is 2 % of the volume of the flue gas stream should be sufficient for oxidation. However, if the volume of air stream 152 is less than 2 % of the flue gas stream 124, or the carbon monoxide concentration is 3 % by volume or greater, additional oxygen maybe added for oxidation purposes. To increase efficiency of oxidation of the carbon monoxide, or to ensure the volume of air stream 152 is at the desired level, the amount of air stream that leaks through the boiler 154 can be increased. Alternatively, an oxygen producing unit, such as an air separator, may provide an oxygen stream 182 to increase the oxidation of the carbon monoxide.

[0024] Oxidation of carbon monoxide present in the flue gas stream 124 allows the exhaust gas 158 to either be reused within the flue gas processing system 100 or contain concentrations of contaminants that are acceptable in release to the atmosphere.


Claims

1. A method of generating a liquefied carbon dioxide stream (156), the method comprising:

generating a flue gas stream (124) carbon dioxide, carbon monoxide and water vapor, wherein the flue gas stream (124) is generated by a chemical looping combustion system (120) including an air reactor (126) and a fuel reactor (128) wherein an oxygen carrier (130) circulates between the air rector (126) and the fuel reactor (128);

subjecting the flue gas stream (124) to an oxidation catalyst (180) for oxidizing the carbon monoxide, thereby generating a carbon dioxide rich flue gas stream (124'); and

processing the carbon dioxide rich flue gas stream (124') to form a liquefied carbon dioxide stream (156) and

returning at least a portion of the exhaust gas (158) to the air reactor (126) if the carbon monoxide present in the flue gas stream (124) is less than one percent (1%) by volume of the carbon dioxide concentration in the flue gas stream (124).


 
2. The method according to claim 1, further comprising:
storing the liquified carbon dioxide stream (156).
 
3. The method according to claim 1, wherein the flue gas stream (124) further comprises contaminants selected from the group consisting of sulfur oxides, nitrogen oxides, mercury, and combinations thereof.
 
4. The method according to claim1, further comprising:
adding oxygen to the flue gas stream (124).
 
5. A method for reducing an amount of contaminants released by a flue gas stream processing system (100), the method comprising:

generating a flue gas stream (124) by combustion of a fuel (122) in a fuel reactor (128) of a chemical looping combustion system (120), wherein the flue gas stream (124) includes water vapor and carbon monoxide;

forming liquefied carbon dioxide (156) by removing water vapor and carbon monoxide from the flue gas stream (124);

generating an exhaust gas (158) during formation of the liquefied carbon dioxide; and

providing at least a portion of the exhaust gas (158) to an air reactor (126) in the chemical looping combustion system (120).


 
6. The method according to claim 5, wherein the chemical looping combustion system (120) includes an air reactor (126) and a fuel reactor (128) wherein an oxygen carrier (130) circulates between the air rector (126) and the fuel reactor (128).
 


Ansprüche

1. Verfahren zum Erzeugen eines verflüssigten Kohlendioxidstroms (156), wobei das Verfahren umfasst:

Erzeugen eines Kohlendioxid-, Kohlenmonoxid- und Wasserdampfrauchgasstroms (124), wobei der Rauchgasstrom (124) durch ein Chemical-Looping-Verbrennungssystem (120), einschließlich eines Luftreaktors (126) und eines Brennstoffreaktors (128), erzeugt wird, wobei ein Sauerstoffträger (130) zwischen dem Luftreaktor (126) und dem Brennstoffreaktor (128) zirkuliert;

Unterziehen des Rauchgasstroms (124) einem Oxidationskatalysator (180) zum Oxidieren des Kohlenmonoxids, wodurch ein kohlendioxidreicher Rauchgasstrom (124') erzeugt wird; und

Verarbeiten des kohlendioxidreichen Rauchgasstroms (124'), um einen verflüssigten Kohlendioxidstrom (156) zu bilden, und

Rückführen zumindest eines Teils des Abgases (158) zu dem Luftreaktor (126), wenn das im Rauchgasstrom (124) vorliegende Kohlenmonoxid weniger als ein Volumenprozent (1 Vol.-%) der Kohlendioxidkonzentration in dem Rauchgasstrom (124) beträgt.


 
2. Verfahren nach Anspruch 1, ferner umfassend:
Aufbewahren des verflüssigten Kohlendioxidstroms (156).
 
3. Verfahren nach Anspruch 1, wobei der Rauchgasstrom (124) ferner Verunreinigungen umfasst, die aus der Gruppe ausgewählt sind, bestehend aus Schwefeloxiden, Stickoxiden, Quecksilber und Kombinationen davon.
 
4. Verfahren nach Anspruch 1, ferner umfassend:
Zusetzen von Sauerstoff zu dem Rauchgasstrom (124).
 
5. Verfahren zum Reduzieren einer Menge von Verunreinigungen, die durch ein Rauchgasstromverarbeitungssystem (100) freigesetzt werden, wobei das Verfahren umfasst:

Erzeugen eines Rauchgasstroms (124) durch Verbrennung eines Brennstoffs (122) in einem Brennstoffreaktor (128) eines Chemical-Looping-Verbrennungssystems (120), wobei der Rauchgasstrom (124) Wasserdampf und Kohlenmonoxid einschließt;

Bilden von verflüssigtem Kohlendioxid (156) durch Entfernen von Wasserdampf und Kohlenmonoxid aus dem Rauchgasstrom (124);

Erzeugen eines Abgases (158) während der Bildung des verflüssigten Kohlendioxids; und

Bereitstellen von zumindest einem Teil des Abgases (158) gegenüber einem Luftreaktor (126) in dem Chemical-Looping-Verbrennungssystem (120).


 
6. Verfahren nach Anspruch 5, wobei das Chemical-Looping-Verbrennungssystem (120) einen Luftreaktor (126) und einen Brennstoffreaktor (128) einschließt, wobei ein Sauerstoffträger (130) zwischen dem Luftreaktor (126) und dem Brennstoffreaktor (128) zirkuliert.
 


Revendications

1. Procédé de génération d'un courant de dioxyde de carbone liquéfié (156), le procédé comprenant :

la génération d'un courant de gaz de combustion (124) de dioxyde de carbone, de monoxyde de carbone et de vapeur d'eau, dans lequel le courant de gaz de combustion (124) est généré par un système de combustion en boucle chimique (120) incluant un réacteur à air (126) et un réacteur à combustible (128) dans lequel un porteur d'oxygène (130) circule entre le réacteur à air (126) et le réacteur à combustible (128) ;

la soumission du courant de gaz de combustion (124) à un catalyseur d'oxydation (180) pour oxyder le monoxyde de carbone, générant de ce fait un courant de gaz de combustion riche en dioxyde de carbone (124') ; et

le traitement du courant de gaz de combustion riche en dioxyde de carbone (124') pour former un courant de dioxyde de carbone liquéfié (156) et

le renvoi d'au moins une partie des gaz d'échappement (158) vers le réacteur à air (126) si le monoxyde de carbone présent dans le courant de gaz de combustion (124) est inférieur à un pour cent (1 %) en volume de la concentration de dioxyde de carbone dans le courant de gaz de combustion (124).


 
2. Procédé selon la revendication 1, comprenant en outre :
le stockage du courant de dioxyde de carbone liquéfié (156).
 
3. Procédé selon la revendication 1, dans lequel le courant de gaz de combustion (124) comprend en outre des polluants choisis parmi le groupe constitué par les oxydes de soufre, les oxydes d'azote, le mercure, et des combinaisons de ceux-ci.
 
4. Procédé selon la revendication 1, comprenant en outre :
l'ajout d'oxygène au courant de gaz de combustion (124).
 
5. Procédé pour réduire une quantité de polluants libérés par un système de traitement de courant de gaz de combustion (100), le procédé comprenant :

la génération d'un courant de gaz de combustion (124) par la combustion d'un combustible (122) dans un réacteur à combustible (128) d'un système de combustion en boucle chimique (120), dans lequel le courant de gaz de combustion (124) inclut de la vapeur d'eau et du monoxyde de carbone ;

la formation de dioxyde de carbone liquéfié (156) en éliminant la vapeur d'eau et le monoxyde de carbone du courant de gaz de combustion (124) ;

la génération d'un gaz d'échappement (158) lors de la formation du dioxyde de carbone liquéfié ; et

la fourniture d'au moins une partie des gaz d'échappement (158) à un réacteur à air (126) dans le système de combustion en boucle chimique (120).


 
6. Procédé selon la revendication 5, dans lequel le système de combustion en boucle chimique (120) inclut un réacteur à air (126) et un réacteur à combustible (128) dans lequel un porteur d'oxygène (130) circule entre le réacteur à air (126) et le réacteur à combustible (128).
 




Drawing









REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description




Non-patent literature cited in the description