Preparation of binderless 3A adsorbents
AssigneeW. R. Grace & Co.
InventorsJames N. Pryor, Chang W. Chi
Life of this patent
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Abstract
Shaped products of a 3A zeolite are formed either as beads or extrudates without any binder remaining. In the case of beads, a 4A powder is mixed with a caustic solution and a metakaolin clay binder to form beads. The beads are converted to a binderless 4A product which is given a partial calcium exchange followed by a potassium exchange to obtain the desired 3A binderless bead. The 3A extrudates are produced by forming binderless 4A extrudates from a 4A powder and clay mixture that contains 40-60% by weight clay. These binderless 4A extrudates are then given a potassium exchange. Both the beads and the extrudates can be used to dry a mixture of a hydrocarbon compound such as ethylene and water.
Claims12
A process of making 3A zeolite binderless beads comprising
- forming beads from a mixture of 4A zeolite powder, a clay binder and a sodium hydroxide solution;
- treating the beads with additional sodium hydroxide to convert the clay binder to a 4A zeolite to provide a 4A binderless bead;
- partially exchanging the 4A binderless bead with a calcium containing solution to form an intermediate bead product;
- exchanging the intermediate bead product with a potassium exchanging solution selected from the group consisting of an aqueous solution of a potassium salt, a potassium hydroxide solution and mixtures thereof to obtain a 3A zeolite binderless bead;
- and
- recovering and activating the potassium exchanged bead product.
A process for making a binderless 3A extrudate from an extrudable mixture of a synthetic 4A zeolite, metakaolin clay, and sodium hydroxide solution, said clay comprising about 40-60% by weight of the total weight of the clay and the zeolite on a dry basis and the amount of sodium hydroxide being in the range of about 90-120% of the stoichiometric amount to convert the clay to a zeolite, said process comprising
- extruding the extrudable mixture to form extrudates;
- aging the extrudates;
- treating the aged extrudates with a dilute solution of sodium hydroxide at an elevated temperature to complete the crystallization of the aged extrudates;
- washing the crystallized extrudates;
- contacting the washed extrudates with a potassium exchanging solution selected from the group consisting of an aqueous solution of a potassium salt, a potassium hydroxide solution and mixtures thereof;
- and
- recovering and activating the potassium exchanged extrudate product.
A 3A binderless bead adsorbent made from a mixture of metakaolin clay and a synthetic 4A zeolite where the clay is present from about 40-60% by weight on a dry basis of the total weight of the clay and zeolite.
A 3A binderless extrudate adsorbent made from a mixture of metakaolin clay and a synthetic 4A zeolite where the clay is present from about 40-60% by weight on a dry basis of the total weight of the clay and zeolite.
Dependencies are inferred from the claim text.