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    公开号:SE0900353A1
    申请号:SE0900353
    申请日:2009-03-16
    公开日:2010-09-17
    发明作者:Anders Lyngfelt；Tobias Mattisson；Alexander Shulman；Erik Cleverstam
    申请人:
    IPC主号:
    专利说明:

    Characteristic of two-stage combustion is that carbon dioxide can be separated without any realgas separation, which could potentially reduce the cost of carbon capture.
    Three-stage combustion has great fundamental similarities with two-stage combustion. First comestwo-stage combustion, and its limitations to be described below. The most importantThe limitation of two-stage combustion is that the process is more difficult to apply to solidsfuels.3 Two-stage pre-combustionTwo-stage combustion, or chemical-looping combustion, is a process of combustion inwhich CO 2 can be separated. The process involves using a metal / metal oxide to transferoxygen from air to a gaseous fuel. In an "air reactor", the metal is oxidized with air, wherebyheat is developed and a "flue gas" in the form of air with reduced oxygen content leaves the reactor, seefigure 1. The metal oxide is forced to the "fuel reactor" where it reacts with the fuel whereby CO2and water vapor is formed. The water vapor can be removed by condensation, which means that cleanCO; obtained. The total heat development for oxidation + reduction is the same as for onedirect combustion and can be used in a similar way for the production of electricity, e.g. onecombined gas turbine / steam turbine process. The chemical reactions will then be, if the fuel is adoptedbe methane, CH4, and if MeO and Me denote are metal oxide and reduced metal oxide(reduced metal oxide here means an oxide with less oxygen than MeO, or alternatively a metalcompletely without oxygen):4MeO + CH4 => 4Me + CO2 + 2H2O (in the fuel reactor) (1)202 + 4Me => 4 MeO (in the air reactor) (2)The net reaction then becomes (reaction 1 + 2):CH4 + 202:> COZ "l"Nz, O 2 CO 2, H 2 O.MeO (+ Me)Air- 'Fuelreactor A4 _ reactor02 + QMG => 2Me0 CHi + 4MeO => CO2+ 2H2O + 4MeMe (+ MeO)Air FuelFigure 1. Principle / design of the two-stage dye firing. The oxygen carrier is symbolized byMeO / Me where MeO is a meta / oxide and Me is a metal or a metal / oxide with loweroxygen content / l than MeO. The fuel here is methane (CH4).2In the process outlined, CO2 is obtained in pure form without any real energy requiredsacrificed for this. The process will require some extra auxiliary energy for e.g. increasedpressure drop but this energy consumption is marginal compared to the energy requiredfor the separation of CO 2 by commercially available methods. Regardless of the choice of process is requiredhowever, energy to compress separated C02 into a disposable product (liquid). Reactorcan be fluidized beds with metal / metal oxide as bed material. Heat to onepower process is obtained partly by cooling the air reactor, partly as heat in the product gases in the firsthand from the air reactor.
    Two-stage combustion is very suitable for gaseous fuels. But a big part ofenergy production and above all carbon dioxide emissions from larger power plants come fromcombustion of solid fuels such as coal. Two-stage combustion is more difficult to applysolid fuels as it would involve a solid phase-solid phase reaction (fuel particles -metal oxide particles) in the fuel reactor. For this reaction to be possible, oxygen is requiredcan be transferred from the oxide particles to the fuel particles in the fuel reactor.
    This can be done through gases that can transport oxygen, e.g. CO 2 and H 2 O, as illustrated byfollowing reactions in which the solid fuel, in a somewhat simplified manner, is assumed to consist only of carbon (C)):C02 + C => 2C0 (4)2CO + ZMeO => 2Me + 2CO2 (5)The net reaction in the fuel reactor will then be:C + 2Me0 => C02 + 21lVle (6)In the same way, water vapor can transfer oxygen:H20 + c => H2 + co i (7)H20 + CO => H2 + CO221-12 + 2lVle0 => 2l / [e + 21-120 (8)The net reaction in the fuel reactor is again:C + 21Vle0 => C02 + ZMe (9)4 Disadvantages of two-stage combustionHowever, there is a difficulty in carrying out these reactions. This is partly what is requireda large mass flow of particles between the reactors to obtain a sufficient oxygen transport.
    On the one hand, the reactions (4) and (7) are known through many years of work to use and developï gasification of solid fuels, very slow, which means they need a longresidence time to react completely in the fuel reactor. If they do not have time to react completely inthe fuel reactor before being passed on with the circulating metal oxide particles tothe air reactor, they will burn in the air reactor and emit carbon dioxide there. The separation ofcarbon dioxide then becomes incomplete. For the process to be meaningful, it is thereforeit is necessary that most of the carbon dioxide is emitted in the fuel reactor.
    The long residence time in combination with the large fl fate of circulating particles, ieresidence time times fl fate, determines the amount of solid material that needs to be present inthe fuel reactor. It would be a great advantage if you could increase the reaction ratesImproving the process of three-stage combustion.In the two-stage combustion described above, reducing gases, i.e. the gaseous one, reactthe fuel or possibly gases derived from a fuel, directly with the metal oxide particles.In three-stage combustion, the oxidation of the solid fuel takes place in two stages. First decomposesthe oxygen carrier, and emits oxygen in gas form. Then the fuel reacts, which can be a solidfuel, with this oxygen. This requires a different type of oxygen carrier than those used intwo-stage combustion. The oxygen carriers needed for three-stage combustion must have the propertyto be able to both absorb oxygen and decompose at suitable temperatures.
    These oxygen carriers are hereinafter generally referred to as MtO - Mt, where MtO is a metal oxide and Mtis the reduced metal oxide. We again leave the possible solid fuel somewhat simplifiedconsists of carbon (C). The two steps in the fuel reactor are then:2MtO + => 2Mt + 02 (decomposition of metal oxide) (10)O 2 + C => CO; (oxidation of fuel) (1 1)If the fuel also contains hydrogen, some water vapor will be formed, reaction (1 lb)(l + 0.5x) O2 + CHgx => CO; + xHgO (oxidation of fuel) (l lb)The third step is the regeneration of the metal oxide:O; + 2l / lt => 2 MtO (in air reactor) (12)The net reaction then becomes (reaction 10 + 11 + 12):CJfÛz => CÛz (13)We see here that the reactions (10) and (12) cancel each other out and the net reaction (13) is identicalwith reaction (11). If the fuel also contains hydrogen, the net reaction will be identical toreaction (1 lb). The metal oxide particles are thus used to move the oxygen to the fuel reactor,so that the combustion can take place there.
    Figure 2 shows the basic design of the process. The important difference compared to,two-stage combustion, Fig. 1, is that a metal oxide is used which spontaneously decomposes inthe fuel reactor. The fuel does not have to react with the metal oxide, but can burn ”normal way ”by reacting with the liberated oxygen. This creates very great opportunitiesfor the use of solid fuels, which cannot react directly with the metal oxide.
    Three-stage combustion means that the solid fuel does not have to undergo the slow onesthe gasification reactions (4) and (7), but can react directly with the oxygen (a rapid reaction,known as combustion). inNg, Og CO 2, H 2 O.ll TiMio (+ Mi)V FuelAir reactorreactor2Mio => zfxm + ozo, + zivn => ziviioc + o, => co,Mi (+ Mio)Air FuelFig. 2. Basic design of the three-stage combustion. The acid carrier is symbolized byMtO / Me where MtO is a metal oxide and Mt is a metal or a metal oxide with loweroxygen content than MtO. The fuel here is slightly simplified carbon (C). Probably need one toosalvage gas, e.g. recycled CO2, or water vapor, to the fuel reactor in the case of solid fuelused. The reactors are probably designed as fluidized beds..1 Process CombinationIt is also conceivable, if not probable, that a process containing oxygen carriers such ascan emit oxygen in practice can be a combination of two- and three-stage combustion.
    Depending on the type of fuel, the properties of the oxygen carrier, as well as operating conditions such asreactor temperature, bed mass, etc., one or the other process may dominate. It is howeverundoubtedly so that an oxygen carrier that has the ability to deliver oxygen can significantly improvethe conversion of the gas, as well as accelerate the conversion of solid fuels..2 Metal oxides previously proposed for three-stage combustionAs mentioned above, the process requires oxygen carriers that both have the ability to both be able toemit and absorb oxygen at appropriate temperatures. Three of these have previously been identifiedx:CuO1CugO and Mn2O3 / Mn3O4, Co3O4 / CoO. CuÛ decomposes in air spontaneously at temperaturesabove 1030 C, MnzOg at temperatures above 820 C and Co3O4 at temperatures above 890 C.
    Table 1 shows the equilibrium pressure of Og as a function of the temperature of these oxide pairs.
    As shown in Table 1, lVIn3O4 should react with air to form Mn2 O3 andbe able to lower the oxygen content to a maximum of 5% if the temperature is 750 C or lower. (5% correspondsan air excess of 25% 9, which may be a normal level in an incineration plant). Whenthese particles are then fed to the fuel reactor, they will decompose and emit 0; ingaseous form, and at the actual temperature this reaction may give an oxygen partial pressure ofmaximum cza 5%. Due to the fact that the reactions that take place in the fuel reactor as a whole areS Mattisson, T., Lyngfelt, A., and Leion, H., Chemical-Looping with Oxygen Uncoupling for Combustion ofSolid Fuels, accepted for publication in International Journal of Green / house Gas Control9 Note that the calculation of the air factor for this process will be slightly different than with normal combustion due to.that the gas is more concentrated as the combustion products, CO 2 and H 2 O, leave the process as a specialde destiny.exothermic, however, one can get a temperature increase that gives a significantly higher partial pressureof Oz, as shown in the table above. For example, a temperature increase of 50C, to 800 C, give an oxygen partial pressure of maximum cza 14%. Internal balances show that atemperature increase of this magnitude can be realistic.
    Table 1. Equilibrium pressure over oxide mixtures.
    T, C P02 over CUÛ / CU2Û P02 ÖVCI "MIl2O3 / MI13Û4 P02 ÖVCI 'CO3O4 / COQ700 0.017725 0.030750 0.05l 0000635775 0.086800 00012 0.139 0.005 826825 00024 0.222850 00046 0.345 0.043l92875 00084 0.526900 0.0l 5 0.787 0265291925 0.026 l .l 57950 0.045975 0.076l. 000 0.124l025 0. l 99l050 0.313In the same way, CugO can react with air during the formation of CuO and be able to lower the maximumthe oxygen content to just under 5% if the temperature is 950 C or lower, see table l. When these particlesthen fed to the fuel reactor, they will decompose and emit 0; in gaseous form, and at itcurrent temperature, this reaction can give an oxygen partial pressure of a maximum of just over 4%. Ondue to the reaction in the fuel clay reactor is the exotherm, however, one can get a temperature increasewhich gives a significantly higher partial pressure of Og, as shown in the table above. So canfor example a temperature increase of 50 C, to 1000 C, give an oxygen partial pressure of maximumc: a 12%. The friend balances made below show that a temperature increase of this magnitudecan be realistic.
    It is also possible to use the temperature increase in the fuel reactor to select a lower onetemperature in the air reactor. With, for example, 925 C in the air reactor, O 2 can be reduced to a minimum2.6%, and with 975 ° C in the fuel reactor, an Og concentration of a maximum of 7.6% can be obtained.
    In the same way, CoO can react with air to form * Co3O4 and be able to lower the maximumthe oxygen content to just under 5% if the temperature is 850 C or lower, see table l. When these particlesthen fed to the fuel reactor, they will decompose and emit O 2 in gaseous form, and at itcurrent temperature, this reaction can give an oxygen partial pressure of a maximum of just over 4%. Forcobalt oxide, the reactions in the fuel reactor are overall weakly endothermic, so anytemperature increase cannot be obtained in the fuel reactor..2.1. Comments on known oxygen carriers with the ability to release oxygen.
    Cobalt oxide is both very expensive and toxic and therefore unsuitable to use.
    Copper oxide, has proven very promising in lab experiments. The low melting temperature canpossibly give technical problems, and copper is furthermore quite expensive.6Manganese oxide is a much cheaper material, but attempts with manganese oxide have not succeededshow that it emits oxygen at some useful rate. Furthermore, the partial pressures for this areoxide too high, one would have to work with temperatures below 750 C tobe able to oxidize.6 New oxygen carriers with the ability to deliver oxygenIn experiments with manganese oxide, where this has been combined with other oxides, it has been possible tochange the oxidation state of manganese so that it can emit oxygen at higher temperatures.
    The following combinations of oxides have in experiments shown good properties when it comes to emittingoxygen at the appropriate temperature: manganese-magnesium (Mn-Mg), manganese-iron (Mn-Fe), manganese-magnesiumnickel (Mn-Ni) and manganese-silicon (Mn-Si).
    Tables 2 and 3 show the designations and composition of the materials examined.
    Table 2 Materials examined with Mn-Mg.
    Raw material mass Sintering Designation Identified-% temperature substances(° C)MnOg / MgO 68.3 1100 51l / I7M1100 Mg2MnO4Batch 5-1 / 1300 51M7M130031 .7MnOg / MgO 68.3 1125 91M7M1125 Mg2MnO4Batch 9-1 / 1150 91M7M1l5031.7 1200 91M7M1200MnO2 / MgO / Ca (O 66.7 1 100 92M7MC1 100 Mg2MnO4,11); / 1150 92M7MC1150 CaMn2O4,Batch 9-2 28.2 1200 92M7MCl 200 CagMnzOv/ 5.1MngOir / MgO 65.4 1100 71l / 165M1100 MggMnOirBatch 7-1 / 1200 71M65M120034.6 1300 7ll / 165M1300MnOg / MgO / TiOg 60.2 1 100 52M6MT1 100 Mgi .zTiozMni .eBatch 5-2 / 043 1 .9/ 7.9Table 3. Materials examined with Mn-F e, Mn-Ni, and Mn-Si.
    Raw material mass% Sintering Identified Designationtemperature substances(° C)Mn3O4 / Fe2O3 80/20 950 FeMnOg 4ll / I8F950Batch 4-1 1100 41M8Fl 1001300 4lM8Fl300Mn3O4 / Fe2O3 80/20 1150 FeMnOg l02lvI8Fl 150Batch l 0-2Mn_ ~, O4 / Fe2O3 60/40 1100 FeMn03 101M6Fl100-l 1200 l 01 M6F1200IVln3O4 / NiO 80/20 950 Mn2Ni04 + Mn2 42M8N950Batch 4-2 1 100 And 42M8Nl1 001300 Mn2NiO4 42M8Nl 300MÅI13O4 / SiO2 80/950 Mn2O3 + SiO2 43M8S950Batch 4-3 20 1100 Mn2O3 + SiO2 43M8Sl100Experimental performanceExperiments have been performed in a small fluidized bed reactor with 15 g of material. Particles of the size125-180 μm has been used. Experiments have been performed partly where oxygen is given off in inert gas, and partly therecombustible gas, methane, passed through the bed. Between each experiment in which the oxygen carrier has given oxygen,inert gas, alternatively reacted with fuel, it has been reoxidized by a gas with normal% oxygen, That reoxidation with 5% oxygen is also possible has also been tested. The following flowshas been used, methane 450 mL fl / min, oxidizing gas 1000 mLn / min, and inert gas 450 mLn / min.
    The ratio of bed mass / fuel fl fate is relatively low, and corresponds to 57 kg / MW. This means thatif the conversion of the fuel is high, this is a very good result.6.1 Materials that combine Mn with Mg.
    Figure 3 shows examples of oxygen concentrations at different temperatures for a material atswitching from gas containing 10% oxygen to pure nitrogen (inert gas). Oxygen begins to fall at about 20s after switching to nitrogen. In a sand bed that does not emit oxygen, it takes another 20-30 sbefore the oxygen concentration becomes zero. The oxygen concentrations seen after this timeis therefore due to the materials emitting oxygen. in12 -02 °° “° -: sme'% -fl-- ssoc....... ..- '50 ° C8 _6 _4 - x¶2 "øøøv ~ n |» - »| ... T,.: .. .. P,0 I I Tïïïïlïïïïl0 100 200 300 400 500time / sFigure 3. Oxygen concentration as a function of time for the oxygen carrier 92M7MC1l00, at 4 differenttemperature. The vertical double line shows the changeover to inert gas. The acid falls / is burned onea moment later, and the delay is due to the time the gas needs to reach the gas / jet.
    Figure 4, shows oxygen concentrations as a function of a). u) is calculated relative mass change inthe oxygen carrier, ie a measure of how much oxygen has been released in total. The clear change inthe direction coefficient of the curves at the beginning shows when the change to nitrogen gas ends andthe oxygen concentration begins to show how much oxygen is released.7 a) 91 0.9995 06.999 0.9985 0.998. the tree-iii i: nsiiazrf-rriitic «Figure 4, Oxygen concentration as a function of w for the different materials, at two differenttemperatures, a) 900 ° C and b) 950 ° C.
    Figure 5a shows gas concentrations during a period when methane fuel is added. TheIt appears from the fi gure that most of the methane is oxidized to CO2. Furthermore, it is clear thatthe reaction is exothermic, as the temperature in the bed increases by just over 5 degrees. Similartemperature increases or higher, up to 30 C, have been observed for all materials, with the exception9for those who had low reactivity. A similar temperature increase is also seen in Figure 5b which showsgas concentrations during oxidation.100 - Gas H06) ~ 960 14 _ Ozßf fl c- Tec) - 960coiicJ íco2 / F / s ígggg _ / ° 955 12 '~ - ' - '' Temperature (C)- ~ -o2 10 - l. '95560 _ ._ - -Temperature (C) 8 _. _ _ * o _ *"" '.._..___ -950' I "" "-95040 - ° '6' '""_ 4 '__ 945 9452 _0 - - 940 0 - f 9400 50 100 150 200 0 200 400 600 800time, S SFigure 5. a) Gas concentrations and temperature at the time of addition of fuel as a function of timefor 92M7MC1100. b) oxygen concentration and temperature at reoxidation of the sameoxygen carrier.
    Figure 6 shows the degree of conversion of the gas, yæd, as a function of omega. The degree of conversionshows how much of the incoming methane has been oxidized to CO2. At 950 C fl era shows offmaterials very high conversion rate,> 90%.0.4al ”.lH.:"”-I0.2 f 'm' '1 ä Q|0 I I I |1 0.995 0.99 0.985 0.90w* taggiga-f 'gq-ggg; HQ ”5fl- Q-ïliwi: TXlÛfÃI * "-!" ^ *QIH-ïflf fl ii-í fi xlïllšü mi ”Figure 6. Degree of conversion as a function of w, for different matter / and at two temperatures: a)900 ° C and b) 950 ° C6.2 Materials that combine Mn with Fe, Ni, and Si.
    The following shows the corresponding results for manganese materials combined with Fe, Ni andSi, Figures 7, 8 and 9, show oxygen release at temperatures 850, 900 and 950 C. Allmaterial emits acid.; 4 1f 02 conc..2 mrvisæso 41rv1aF11uo mzr-nsnisu ° 2 °° “° '---- miviamzoo -n-mvvisF fl oo ~~ - ~ u «--- ~ 1oiiv1sr1zon f _, _ 43, V, 8s950 wvws fl oo+ 42M8N950 42M8FJ1 1 0D --- A --- 42I '«/ | Sf l1300...., 4 ......_.... §0 _ _ ._ ._._ .. _ _ __. you. a .... ._ 1 03995 0.999 09985 0.998 039751 03998 03996 01-7994 u:(k)Figure 7. Oxygen concentration as a function of w at 850 C.6 _- 10 1I Oacunc. 1 Qzggm;»I 41MaFsso 41rv1a1 = 1 1 on» ------ 1n2w1ar = 115oø i---- 41rwa1 = 1zuo -n-ioixvieFno-J 1n1rv1ß | = 12o0 U 2 Q 5I -v-43I1oS9 AMSL-t- * Üixliššhlšläii 43118011 100 mr "4I-2Nl-9N130O 6 Vl4 l-~ 12 ÉinÛ i "s *” mf ~ '~ "W' r r 'H"' f "m me” * ^ ~~ "“ "" '- "' m * *" w rm ”* ^ - .I 0998 0396 09941 03998 09996 09994 00992 0.999 09988 03986 03984 mNFigure 8. Oxygen concentration as a function of w at 900 C.4 _02 conc.~~~~ 42M8F ~ l1 100 43Tv18S11ÛÛ2ingwv., 'ik-vw"a__ _. ' > int "" K- .... v'** ø§, i i * * * Mk -: - x-a-i- fi- a-fn fi- x-ia-xi-maæåmsanma1 09999 119998 03997 09996 09995 Ü.9994D.)Figure 9. Oxygen concentration as a function of w at 950 C.
    Figures 10-12 show the degree of conversion of the same material at temperatures 850, 900 and 950C.111 'fi à....... _0: 4: MrxnefssoÄ ä ----- ~ - 41rv1sF1100(16 imi .. ,,,.; _: _, __ Q, '&. ,,: ..- ^' M - - 102rv1s | = 11s0x f 'www ---- 41r / | a | = 1300-I-101MsF11000.4 ~ --l --- 101M6F120D43 | V13S1100- | r-42M8I l95O--- k-- 42lv18N1100- 1: - 42MêN1300'I 0.995 0.99 0.985 0.98 0.975 0.97 0.965 0.96la!Figure 10. Degree of conversion as a function of w at 850 C.
    . . . . . . Q. . . . , _ __0.8__- 41M8F950----- - 41Ma | = 1100- - 102Mß | = 1150---- 41 | wsF1s00-p-mnnemmo101rv1eF12000.4 <> -4-43016505043Mas11004% - -n-42MaN0500.2 4 »42rwsN1100-f: zzrwarnsoo0.60- ~~ -'í“1 0.995 0.99 0.985 0.98 0.975 0.97 0.965 0.96 0.955wFigure 11. About degree of irrigation as a function of w at 900 C.12* ¿'I won., Gav; k 4 in;Gig _ § ~ ... O ~ - .. * _ u.n ._. Y0.5 rfl- Q - f 43Nl8 $ l1ÛÛfl- k "4ZM3FH1ÛÜOh, 4 i 0 2 4)OhÜ ._ a-. _ _ a å .. ._ ..._ .y m, H.. ...__,. .. _._., '........, ._, .._.>. _. .IN1 0.995 H99 (IQ-QS G38 0.975 Û.97Figure 12. About degree of irrigation as a function of w at 950 C.6.3 Comment on experiments with new oxygen carriersThe experiments clearly show that the examined materials have the ability to emit oxygen, as well as that many ofthe materials are capable of providing very high conversion of constituent gaseous fuel.
    All materials also show a clearly exotic reaction with fuel, this is a lotadvantageous then enables a higher temperature in the fuel reactor.7 FuelsThe process can be used for both solid, liquid and gaseous fuels. Its the biggestadvantage is when using solid fuels. Solid fuels may include fuels withvarying content of volatile constituents such as petroleum coke, coke, biofuels and coal withvarying fl content from low ant anthracite to high lign lignite. Common to thesefuels are that after fl volatile substances have left a coke residue which is difficult to reactdirectly with a metal oxide, see sections 3 and 4 above. However, the volatile constituents caneither react with liberated oxygen or, by a gas-solid phase reaction, directly withthe metal oxide particles. For the process to which the patent application relates, however, it can be experimentalbe difficult to easily show whether volatile constituents react directly with,the metal oxide or with liberated acid.
    One consequence of the above reasoning is that for most solid fuels one comespart of the fuel to be given off as fl constituent constituents, ie as gas, which can reactdirectly with the metal oxide. This means that the fuel is not necessarily in its entiretyreacts according to the three-step mechanism described above.
    This is even more true if the process is applied to gaseous or liquid fuels,that part of the reaction can take place directly between the metal oxide and the gas.8 Design of process13The process can be conveniently designed by using fluidized beds as reactors.
    The process can then be designed as a modified circulating fl unidised bed boiler, whichmeans that commercially well-known technology for the reactor system can be used in part, see figure 6.l "-â / l / ”lfN2 (and a little O2)t * toê 3_É- fuelfluidizing gasairFigure 13. Example of how reactor systems can be designed. 1 / uft reactor with high speed aspulls particles upwards, 2 particle separation, 3 fuel reactor. Two fluidized so-calledparticle / ridge prevents the gases in the two reactors from mixing.
    In Figure 6, the fuel reactor is designed as a bubbling fl unidised bed, but it can alsobe a circulating fl uidized bed. Furthermore, it can be modified in various ways to reducethe possibility of unburned fuel to follow the particle flow to the lu reactor. It canfor example, sectioned, or equipped with devices that return fuel particles.8 SummaryThe patent application relates to the use of new materials in incineration processes,two-stage combustion or three-stage combustion, as well as combinations of these processes,which enables the capture of carbon dioxide. Three-stage combustion means that the combustion takes place inthree stages in two reactors, an air reactor where a metal oxide absorbs oxygen from the combustion air(step 1), and a fuel reactor where the metal oxide decomposes and emits oxygen (step 2) and wherethis oxygen reacts with a fuel (step 3). Two-stage combustion means that the combustiontakes place in two stages in two reactors, an air reactor where a metal oxide absorbs oxygen fromthe combustion air (step 1), and a fuel reactor where the metal oxide reacts with a fuel(step 2) so that oxygen is transferred to the fuel. The process is applicable to carbon dioxide capturefrom combustion, for example in order to reduce the climate impact.
    Results for the oxides examined, manganese oxides in combination with oxides ofeither iron, magnesium, silicon or nickel, show that they have the ability to give off oxygen. Theseshould thus be able to function in an indirect combustion process where they take up oxygen in a 'air reactor and then spontaneously decomposes during the release of oxygen in a fuel reactor. IN14the fuel reactor can then react further with oxygen with a fuel. The reaction with the fuellowers the oxygen concentration and can thus accelerate the decomposition of the metal oxide particles.
    Furthermore, the summing reaction in the fuel reactor is exothermic, which can give a temperature increase inthe fuel reactor. This temperature increase is favorable for the process as it furtheraccelerates the decomposition of the metal oxide in the fuel reactor, alternatively allows a lower temperature inthe air reactor. The latter can then enable a more complete conversion of the air, ielower oxygen concentration.
    At the same time, the oxygen carrier can also react directly with the fuel and oxidize it. Althoughthe fuel can thus be oxidized directly by the oxygen carrier, or indirectly by oxygen emitted fromthe oxygen carrier, it is undoubtedly so that the oxygen release significantly facilitates the fuelconversion, which can provide more complete conversion of gas, as well as faster conversionof solid fuels.
    The process provides the opportunity to burn solid and gaseous fuels in such a way thatthe combustion products carbon dioxide and water vapor can be obtained in a separate fl fate. Then water vaporis easy to separate from carbon dioxide by lowering the temperature below the condensation point,more or less pure carbon dioxide can be obtained from the proposed combustion process.
    If the separation takes place in order to avoid emissions of this climate-affecting gas, storage canfor example, geologically.
    权利要求:
    Claims (9)
    [1]
    A method in which an oxygen carrier material is used in three-stage combustion, two-stage combustion or a combination of these processes, characterized in that the oxygen carrier material is based on a combination of an oxide of manganese and another oxide, here called auxiliary oxide, and that this combined oxide is capable of releasing oxygen. .
    [2]
    Process according to Claim 1, characterized in that the fuel partially reacts directly with the metal oxide.
    [3]
    Process according to Claim 1 or 2, characterized in that the solid material containing metal oxide is present in particulate form and in that the reactors used are ididised beds.
    [4]
    Process according to one of Claims 1 to 3, characterized in that the fuel reacts to at least 10% with the liberated oxygen.
    [5]
    Process according to one of Claims 1 to 3, characterized in that the fuel reacts to at least 30% with the liberated oxygen.
    [6]
    Process according to one of Claims 1 to 3, characterized in that the fuel reacts to at least 50% with the liberated oxygen.
    [7]
    Process according to one of Claims 1 to 6, characterized in that the fuel is at least 80% a solid fuel.
    [8]
    Process according to one of Claims 1 to 6, characterized in that the fuel is at least 60% a solid fuel.
    [9]
    Process according to one of Claims 1 to 8, characterized in that a temperature increase occurs during the release of oxygen and the oxidation of fuel, or during a direct reaction between fuel and oxygen carrier, as a result of these reactions being exothermic together. Process according to one of Claims 1 to 9, characterized in that the oxygen carrier consists of more than 60% of a manganese oxide and auxiliary oxide. Process according to one of Claims 1 to 9, characterized in that the oxygen carrier consists of more than 80% of a manganese oxide and auxiliary oxide. Process according to one of Claims 1 to 11, characterized in that the auxiliary oxide is iron oxide and in that the mass ratio of iron-manganese is in the range 0.1 to 1. Process according to one of Claims 1 to 1, characterized in that the auxiliary oxide is iron oxide and in that the mass ratio of iron-manganese is in the range 0.2-0.4. Process according to one of Claims 1 to 11, characterized in that the auxiliary oxide is magnesium oxide and in that the mass ratio of the magnesium oxide is in the range 0.3 to 1. Process according to one of Claims 1 to 11, characterized in that the auxiliary oxide is silica and in that the mass ratio of silica-manganese is in the range 0.05-0.5. Process according to one of Claims 1 to 1, characterized in that the auxiliary oxide is silica and in that the mass ratio of silica-manganese is in the range 0.1 to 0.3. Process according to one of Claims 1 to 11, characterized in that the auxiliary oxide is nickel oxide and in that the mass ratio of the nickel oxide is in the range 0.1-0.5. Process according to one of Claims 1 to 1, characterized in that the auxiliary oxide is nickel oxide and in that the mass ratio of nickel-manganese is in the range 0.2-0.4. 17
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    同族专利:
    公开号 | 公开日
    SE534428C2|2011-08-16|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US8555652B1|2008-06-13|2013-10-15|Zere Energy and Biofuels, Inc.|Air-independent internal oxidation|
    法律状态:
    2015-12-01| NUG| Patent has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    SE0900353A|SE534428C2|2009-03-16|2009-03-16|New oxygen carriers for two- and / or three-stage combustion|SE0900353A| SE534428C2|2009-03-16|2009-03-16|New oxygen carriers for two- and / or three-stage combustion|
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