US 6,280,503 B1 · Carbon dioxide adsorbents containing magnesium oxide suitable for use at high temperatures

Abstract

Adsorption of carbon dioxide from gas streams at temperatures in the range of 300 to 500° C. is carried out with a solid adsorbent containing magnesium oxide, preferably promoted with an alkali metal carbonate or bicarbonate so that the atomic ratio of alkali metal to magnesium is in the range of 0.006 to 2.60. Preferred adsorbents are made from the precipitate formed on addition of alkali metal and carbonate ions to an aqueous solution of a magnesium salt. Atomic ratios of alkali metal to magnesium can be adjusted by washing the precipitate with water. Low surface area adsorbents can be made by dehydration and CO2 removal of magnesium hydroxycarbonate, with or without alkali metal promotion. The process is especially valuable in pressure swing adsorption operations.

Claims9

Dependent claims

In a pressure swing adsorption process for adsorbing carbon dioxide from a gas stream containing carbon dioxide the improvement which comprises bringing said gas stream into contact with a magnesium oxide-containing adsorbent at a temperature in the range of 300 to 500° C., said adsorbent represented by the chemical formula:

{(M2CO3)m(2MHCO3)(1−m)}n(MgCO3)p(MgO)(1−p).xH2O
wherein M is an alkali metal, 0≦m≦1, 0≦n≦1.30, 0≦p<1 and x represents the extent of hydration, with the proviso that when n equals 0 the MgO is made by the dehydration and CO2 removal of {MgCO3}y.{Mg(OH)2}(1−y).xH2O;
in which 0.1≦y≦0.9 and x indicates the extent of hydration.

Dependencies are inferred from the claim text.

Facts

Application

09/370,006Filed 6 Aug 1999

Granted

28 Aug 2001

Term ends

Not estimatedThe source records don’t support an estimate.

Classification19 codes

B01D 53/62
Removing components of defined structure: carbon oxides
B01D 53/02
Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g.…: by…
B01J 20/041
Comprising compounds of alkali metals, alkaline earth metals or magnesium: oxides or hydroxides
B01J 20/043
Comprising compounds of alkali metals, alkaline earth metals or magnesium: carbonates or bicarbonates, e.g. limestone, dolomite, aragonite

Carbon dioxide adsorbents containing magnesium oxide suitable for use at high temperatures

Life of this patent

Carbon dioxide adsorbents containing magnesium oxide suitable for use at high temperatures

Life of this patent

Abstract

Claims9