Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
  • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
  • C01B3/06—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents
  • C01B3/12—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of inorganic compounds containing electro-positively bound hydrogen, e.g. water, acids, bases, ammonia, with inorganic reducing agents by reaction of water vapour with carbon monoxide
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
  • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
  • C01B3/22—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by decomposition of gaseous or liquid organic compounds

Definitions

• the invention generally relates to the carbon monoxide shift reaction CO + H 2 O-> CO 2 + H 2 .
• the large-scale use of this reaction is considered.
• the carbon monoxide shift reaction is one of the most important reactions in the chemical industry. Recently, this chemical reaction has also become important for fossil fuel power plants. The background for this is the current trend of low-carbon power generation with fossil fuels
• a commonly used prior art combination demonstrates the pre-combustion approach with carbon dioxide separation combined with the gas-phase carbon monoxide shift reaction.
• a second subprojects process the separation of the carbon dioxide by physical gas scrubbing, for example, a Rectisol laundry.
• the carbon dioxide into cooled methanol is absorbed at about -40 0 C., Since these low temperatures are needed to In order to be able to sufficiently separate the carbon dioxide, a large amount of energy must be expended for the cooling, which lowers the overall efficiency of the power plant.
• European Patent EP 0 299 995 B1 discloses a process for the conversion of carbon monoxide and water to carbon dioxide and hydrogen
• the combination of a carbon monoxide shift reaction described above with simultaneous removal of the carbon dioxide formed from the fuel gases is carried out in the liquid phase, in particular by mentioning Example No. 6 and Patent Document 2 in this process about 2% water content as solvent l, wherein its pH is increased by the addition of a carbonate such as potassium carbonate.
• the chemical reactions, which can be spatially separated, are as follows:
• the invention has for its object to provide a method and an apparatus for carrying out the carbon monoxide shift reaction with improved overall efficiency.
• the solution of this task corresponds in each case to a combination of features of an independently formulated patent claim.
• Advantageous embodiments can be found in the dependent claims.
• the invention is based on the finding that the thermal decomposition of the hydrogencarbonate HCO 3 " or of the carbonates CO 3 and the expulsion of the carbon dioxide CO 2 can not in each case be carried out completely in the methanolic solution of the second reactor, since this solution
• a solid can be separated from the reaction mixture and subsequently decomposed in an additional fourth reactor for the expulsion of carbon dioxide
• the carbon monoxide shift reaction is doing in f Lüssiger phase performed.
• the formation of the two gases hydrogen and carbon dioxide takes place at different locations, as a result of which their representation can be achieved separately from one another.
• the energy demand of such a designed process is lower than that of a carbon monoxide shift reaction in the gas phase with subsequent separation of hydrogen and carbon dioxide.
• the decomposition of the solid, a bicarbonate or a carbonate does not proceed without further measures, the dissolution of the solid can be preceded by a solvent which has the highest possible boiling point, such as water, in order to prevent high solvent losses.
• a preferred precipitation of the bicarbonate can be brought about for example by lowering the temperature in the precipitation reactor advantageous.
• the use of a saturated bicarbonate solution results in that bicarbonate formed in the first reactor and in the third reactor can not be dissolved and thus precipitates by itself.
• the precipitation may be carried out further by addition of apolar, but miscible with the first solvent, the second solvent, wherein the second solvent serves as a precipitant for salts. After the precipitation, corresponding additives can be distilled off again.
• a further advantageous possibility for precipitating the bicarbonate is the addition of a readily soluble salt with the same cation as is present in the hydrogencarbonate.
• the solubility product of the hydrogen carbonate salt is already achieved at a low bicarbonate concentration.
• Figure 1 shows an arrangement of four reactors, wherein in the second reactor, a solid bicarbonate is separated, which in the fourth reactor is decomposed thermally under carbon dioxide release,
• Figure 2 shows an arrangement of four reactors corresponding to Figure 1, wherein a carbonate as
• Figure 3 shows a listing of equations (1), (2) and (3), these three equations representing in sum the carbon monoxide shift reaction, as known in the art.
• equations (1), (2) and (3) based on the reactions according to equations (1), (2) and (3), further reaction equations are given for how the carbon monoxide shift reaction proceeds in a first reactor, second reactor and third reactor.
• formation of formate takes place with simultaneous formation of hydrogencarbonate.
• equation (3) occurs a reaction of formate with water to bicarbonate and hydrogen.
• Equation (2) bicarbonate is decomposed elsewhere in the course of the reaction to release carbon dioxide.
• reaction equations 2.1 and 4.1 are exemplarily formulated for the use of alkali metal ions. Other cations may equally be suitable for carrying out the reactions, with the reaction equations 2.1 and 4.1 then changing accordingly.
• Solvent and dissolved components from the second reactor 2 and non-gaseous components from the fourth reactor 4 can be recycled to the first reactor 1
• fourth reactor 4 is carried out after an optional drying of the precipitate from the second reactor 2, a thermal decomposition according to equation 4.1.
• the carbonate M 2 CO 3 is brought together with the water in the recirculated stream of the second reactor 2 to the first reactor 1, so that thereby the Bonatatniklauf is closed.
• the process presented can also be carried out with other cations in an analogous manner, for example with the ammonium ion or alkaline earth metal ions.
• a further adaptation of the method provides that instead of a weakly alkaline carbonate buffer system, a strongly alkaline solution of hydroxides is used.
• a strongly alkaline solution of hydroxides is used instead of a weakly alkaline carbonate buffer system.
• reaction equations 2.2 and 4.2 are not intended to be limiting to a particular alkali metal (M). Other cations may equally be suitable for carrying out the reactions; the reaction equations change accordingly.
• the second variant according to the reaction equations (1.2), (3.2), (2.2) and (4.2) takes place in the additional fourth reactor 4 after drying of the precipitate from the second reactor 2, a thermal decomposition of the carbonate M 2 CO 3 .
• the oxide M 2 O is introduced into the recirculated stream of the second reactor 2 to the first reactor 1. There it reacts with water to the hydroxide, so that thereby the material cycle is closed.
• the corresponding equation is:
• the reaction system according to the second variant has the advantage that after the first reactor 1 in the solvent, the equilibrium concentration of carbon dioxide CO 2 will be substantially lower than when using the first variant according to the equations (1.1), (3.1), (2.1), (4.1). As a result, the undesirable desorption of the carbon dioxide together with the hydrogen H 2 formed in the third reactor 3 is very strongly suppressed and thus the carbon dioxide losses are reduced with or into the hydrogen stream.
• the solvent used may be aqueous methanol, water or even a polar solvent.
• the condition is that the salts involved are soluble.
• the decomposition of the bicarbonate or of the carbonate does not take place in a pumped-over solution which also contains dissolved fuel gases, but takes place after the precipitation of a solid.
• the solid is, according to variant 1, the bicarbonate and according to variant 2, the carbonate. In a separate reactor, the decomposition of the solid is carried out accordingly. This measure can both Solvent losses and fuel gas losses are avoided.
• the pH range can be increased, thus significantly reducing the carbon dioxide equilibrium concentration in the solution and at the same time reducing unwanted carbon dioxide desorption with the residual gases in the first reactor 1 or with the hydrogen in the third reactor 3. Overall, this increases the degree of carbon dioxide capture and the losses of fuel gas fall.
• the first variant is shown, which as a solid in the second reactor 2, a hydrogen carbonate ausbringt, which is thermally decomposed in the 4th reactor 4 with release of carbon dioxide.
• FIG. 2 shows a scheme corresponding to the second variant, which has a carbonate as solid instead of the hydrogen carbonate.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Inorganic Chemistry (AREA)
• Carbon And Carbon Compounds (AREA)
• Gas Separation By Absorption (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Treating Waste Gases (AREA)

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• 2009
  • 2009-07-30 DE DE102009035388.7A patent/DE102009035388B4/de not_active Expired - Fee Related
• 2010
  • 2010-06-25 CN CN201080033865.8A patent/CN102471052B/zh not_active Expired - Fee Related
  • 2010-06-25 IN IN350DEN2012 patent/IN2012DN00350A/en unknown
  • 2010-06-25 WO PCT/EP2010/059094 patent/WO2011012385A1/de not_active Ceased
  • 2010-06-25 RU RU2012107708/04A patent/RU2542983C2/ru not_active IP Right Cessation
  • 2010-06-25 US US13/387,170 patent/US8623240B2/en not_active Expired - Fee Related
  • 2010-06-25 EP EP10728652.8A patent/EP2459480B1/de not_active Not-in-force

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