CARBON DIOXIDE ADSORBENTS CONTAINING MAGNESIUM OXIDE SUITABLE FOR USE AT HIGH TEMPERATURES

摘要

Adsorption of carbon dioxide from gas streams at temperatures in the range of 300 to 500 .degree.C is carried out with a solid adsorbent containing magnesium oxide, preferably promoted with an alkali metal carbonate or bicarbonate so that th e atomic ratio of alkali metal to magnesium is in the range of 0.006 to 2.60. Preferr ed adsorbents are made from the precipitate formed on addition of alkali metal and carbona te 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, wi th or without alkali metal promotion. The process is especially valuable in pressu re swing adsorption operations.