CO2-Sorptive Pellets and Uses Thereof

• US 20100196259A1
• Filed: 12/03/2009
• Published: 08/05/2010
• Est. Priority Date: 02/05/2009
• Status: Abandoned Application

• Current Assignee: Air Products and Chemicals Incorporated (Linde Plc)
• Original Assignee: Air Products and Chemicals Incorporated (Linde Plc)
• Inventors: Wilhelm, Frederick Carl, Garg, Diwakar
• Application Number:
  US12/630,388
• Publication Number:
  US 20100196259A1
• Time in Patent Office: Days
• US Class Current: 423/651
• CPC Class Codes: B01D 2251/404 of calcium
• CPC Class Codes: B01D 2253/112 Metals or metal compounds not provided for in B01D2253/104 or B01D2253/106
• CPC Class Codes: B01D 2253/304 Linear dimensions, e.g. particle shape, diameter
• CPC Class Codes: B01D 2253/308 Pore size
• CPC Class Codes: B01D 2253/311 Porosity, e.g. pore volume
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/02 by adsorption, e.g. preparative gas chromatography solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: B01J 20/041 Oxides or hydroxides
• CPC Class Codes: B01J 20/28004 Sorbent size or size distribution, e.g. particle size
• CPC Class Codes: B01J 20/28011 Other properties, e.g. density, crush strength
• CPC Class Codes: B01J 20/2803 Sorbents comprising a binder, e.g. for forming aggregated, agglomerated or granulated products
• CPC Class Codes: B01J 20/28054 characterised by their surface properties or porosity
• CPC Class Codes: B01J 20/28069 Pore volume, e.g. total pore volume, mesopore volume, micropore volume
• CPC Class Codes: B01J 20/28085 being more than 50 nm, i.e. macropores
• CPC Class Codes: C01B 2203/0233 the reforming step being a steam reforming step
• CPC Class Codes: C01B 2203/0425 In-situ adsorption process during hydrogen production
• CPC Class Codes: C01B 2203/043 Regenerative adsorption process in two or more beds, one for adsorption, the other for regeneration
• CPC Class Codes: C01B 2203/0475 the impurity being carbon dioxide
• CPC Class Codes: C01B 2203/1005 Arrangement or shape of catalyst
• CPC Class Codes: C01B 2203/1041 : Composition of the catalyst
• CPC Class Codes: C01B 2203/1058 : Nickel catalysts
• CPC Class Codes: C01B 2203/1082 : Composition of support materials
• CPC Class Codes: C01B 2203/1088 : Non-supported catalysts
• CPC Class Codes: C01B 2203/1241 : Natural gas or methane
• CPC Class Codes: C01B 2203/1614 : Controlling the temperature
• CPC Class Codes: C01B 3/38 : using catalysts
• CPC Class Codes: C01B 3/56 : by contacting with solids; Regeneration of used solids C01B3/508 takes precedence
• CPC Class Codes: Y02C 20/20 : of methane
• CPC Class Codes: Y02C 20/40 : of CO2
• CPC Class Codes: Y02P 20/151 : Reduction of greenhouse gas [GHG] emissions, e.g. CO2

Abstract

CO₂ sorptive pellets and/or granules and their use for removing CO₂ from CO₂-containing gases and for producing hydrogen. CO₂ sorptive pellets are suitable for use in fixed bed reactors and the like due to sufficient crush strength. CO₂ sorptive granules are suitable for moving, ebullated, expanded and fluidized beds. The CO₂ sorptive pellets and/or granules comprise calcium oxide and/or magnesium oxide and at least one binding agent such as calcium titanate, calcium aluminate, calcium zirconate, magnesium titanate, magnesium aluminate, and magnesium zirconate. A method for making the CO₂-sorptive pellets is described. The CO₂ sorptive pellets optionally comprise at Ni, Pd, Pt, and/or Rh.

Claims

1. An aggregate suitable for carbon dioxide sorption comprising:

25 to 85 mass % of at least one binding agent selected from the group consisting of calcium titanate, calcium aluminate, calcium zirconate, magnesium titanate, magnesium aluminate, and magnesium zirconate; and

15 to 75 mass % of calcium oxide, magnesium oxide or mixture of calcium oxide and magnesium oxide;

wherein the aggregate is a pellet or a granule having a median pore diameter in a range of 500 nm to 5000 nm and a porosity in a range of 45% to 80%.

2. The aggregate of claim 1 further comprising:

0.1 to 10 mass % of at least one metal selected from the group consisting of Ni, Pt, Rh, and Pd.

3. The aggregate of claim 1 wherein the aggregate is a pellet and has a characteristic length of 0.1 mm to 3 mm.

4. The aggregate of claim 1 wherein the aggregate is a pellet and has a crush strength of 1 to 15 lbf/mm (4 to 67 N/mm) as determined in accordance with ASTM standard test method D 6175-03.

5. The aggregate of claim 1 wherein the aggregate is a pellet and has a structure wherein the crush strength of the pellet is retained within 1 to 15 lbf/mm (4 to 67 N/mm) after 50 cycles of CO₂ sorption and CO₂ desorption wherein the CO₂ sorption is by exposing the pellet to a humidified CO₂-containing gas comprising 97 to 98 vol. % CO₂ and 2 to 3 vol. % H₂O at 750°

C. and CO₂ desorption is by exposing the pellet to humidified air at 750°

C.

6. The aggregate of claim 1 wherein the aggregate is a granule and has a characteristic length of 50 microns to 3 mm.

7. The aggregate of claim 1 wherein the aggregate is a granule and has a structure wherein the granule retains its shape and size after 50 cycles of CO₂ sorption and CO₂ desorption wherein the CO₂ sorption is by exposing the granule to a humidified CO₂-containing gas comprising 97 to 98 vol. % CO₂ and 2 to 3 vol. % H₂O at 750°

C. and CO₂ desorption is by exposing the granule to humidified air at 750°

C.

12. The aggregate of claim 1 made by the method of claim 8.

13. The aggregate of claim 1 made by the method of claim 9.

14. The aggregate of claim 1 made by the method of claim 10.

16. An apparatus for producing a CO₂-depleted gas from a CO₂-containing gas, the apparatus comprising:

a bed containing a plurality of CO₂-sorptive aggregates, wherein the plurality of CO₂-sorptive aggregates comprise an aggregate as claimed in claim 1.

17. A process for producing a CO₂-depleted gas from a CO₂-containing gas in an apparatus as claimed in claim 16, the process comprising:

(i) passing the CO₂-containing gas through the bed under conditions sufficient to sorb CO₂ and form calcium carbonate and/or magnesium carbonate with the plurality of aggregates and thereby forming the CO₂-depleted gas;

(ii) regenerating the bed by passing a purge gas through the bed under conditions sufficient to liberate CO₂ from the plurality of aggregates and withdrawing a by-product gas comprising CO₂ from the apparatus; and

(iii) repeating (i) and (ii) in a cyclic manner.

18. The process of claim 17 wherein the conditions sufficient to sorb CO₂ and form calcium carbonate and/or magnesium carbonate include a temperature ranging from 600°

C. to 800°

C. and a pressure ranging from 1 to 100 atmospheres, and wherein the conditions sufficient to liberate CO₂ include a temperature ranging 650°

C. to 900°

C. and a pressure ranging from 0.9 to 100 atmospheres, and wherein the purge gas comprises at least one of nitrogen and steam and the purge gas optionally comprises oxygen.

19. A reactor for producing a hydrogen-containing gas, the reactor comprising:

a bed containing CO₂-sorptive aggregates, optionally containing steam-hydrocarbon reforming catalyst aggregates comprising a reforming catalyst, and optionally containing a metal oxide of at least one of Cu, Fe and Ni, wherein the CO₂-sorptive aggregates comprise an aggregate as claimed in claim 1, and wherein if the bed does not contain the steam-hydrocarbon reforming catalyst aggregates and does not contain the metal oxides, then at least a plurality of the CO₂-sorptive aggregates include the at least one metal selected from the group consisting of Ni, Pt, Rh and Pd.

20. A process for producing a hydrogen-containing gas in a reactor as claimed in claim 19, the process comprising:

(i) in a production step, introducing steam and a feed gas containing methane into the reactor, reacting the methane and the steam in the bed in the presence of at least one of the reforming catalyst, the metal oxide and the at least one metal under reaction conditions sufficient to form hydrogen, sorb CO₂ and form calcium carbonate and/or magnesium carbonate, and withdrawing a product gas comprising hydrogen from the reactor;

(ii) in a regeneration step, regenerating the CO₂-sorptive aggregates by passing a purge gas through the bed under conditions sufficient to liberate CO₂ from the CO₂-sorptive aggregates and withdrawing a by-product gas comprising CO₂ from the reactor; and

(iii) repeating (i) and (ii) in a cyclic manner.

21. The process of claim 20 wherein the reaction conditions sufficient to form hydrogen, sorb CO₂ and form calcium carbonate and/or magnesium carbonate include a temperature ranging from 350°

C. to 800°

C. and a pressure ranging from 1 to 100 atmospheres, and wherein the conditions sufficient to liberate CO₂ include a temperature ranging 450°

C. to 900°

C. and a pressure ranging from 0.9 to 100 atmospheres, and wherein the purge gas comprises at least one of nitrogen and steam and the purge gas optionally comprises oxygen.

8. A method for making an aggregate suitable for carbon dioxide sorption, the method comprising the steps of:

(a) preparing a mixture, the mixture comprising;

at least one of calcium carbonate and magnesium carbonate in an amount to provide the 15 to 75 mass % of calcium oxide, magnesium oxide or mixture of calcium oxide and magnesium oxide in the aggregate;

at least one of a calcium precursor and a magnesium precursor in an amount to provide the 25 to 85 mass % of the at least one binding agent in the aggregate;

at least one of TiO₂, Al₂O₃, ZrO₂, Al(OH)₃ and AlO(OH) in an amount to provide the 25 to 85 mass % of the at least one binding agent in the aggregate; and

20 to 80 mass % water;

(b) forming a green aggregate from the mixture;

(c) heating the green aggregate from a first temperature to a second temperature at a first average heating rate of 0.1°

C./minute to 10°

C./minute,

wherein the first temperature is within a first temperature range wherein the first temperature range is between 5°

C. and 50°

C., and

wherein the second temperature is a minimum temperature of a second temperature range, the second temperature range extending from the minimum temperature of the second temperature range to a maximum temperature of the second temperature range wherein the minimum temperature of the second temperature range is 600°

C. and the maximum temperature of the second temperature range is 750°

C.;

(d) maintaining the green aggregate within the second temperature range for a first time period of between 15 minutes and 4 hours;

(e) heating the green aggregate from the maximum temperature of the second temperature range to a third temperature at a second average rate of 0.1°

C./minute to 10°

C./minute,

wherein the third temperature is a minimum temperature of a third temperature range, the third temperature range extending from the minimum temperature of the third temperature range to a maximum temperature of the third temperature range wherein the minimum temperature of the third temperature range is 900°

C. and the maximum temperature of the third temperature range is 1050°

C.;

(f) maintaining the green aggregate within the third temperature range for a second time period of between 15 minutes and 4 hours; and

(g) cooling the green aggregate to a fourth temperature, wherein the fourth temperature is within a fourth temperature range wherein the fourth temperature range is between 0°

C. and 50°

C., to make the aggregate;

wherein the green aggregate is exposed to an atmosphere comprising oxygen during at least one of steps (a) through (f).

9. The method of claim 8 wherein the mixture comprises 20 to 40 mass % water and wherein the green aggregate is a green pellet and the aggregate is a pellet.

10. The method of claim 8 wherein the green aggregate is exposed to the atmosphere comprising oxygen during all of steps (a) through (f).

11. The method of claim 8 wherein the mixture further comprises 0.1 to 10 mass % of at least one metal selected from the group consisting of Ni, Pt, Rh, and Pd.

15. The aggregate of claim 2 made by the method of claim 11.