Increased thermal conductivity monolithic zeolite structures
A monolith comprises a zeolite, a thermally conductive carbon, and a binder. The zeolite is included in the form of beads, pellets, powders and mixtures thereof. The thermally conductive carbon can be carbon nano-fibers, diamond or graphite which provide thermal conductivities in excess of about 100 W/m·K to more than 1,000 W/m·K. A method of preparing a zeolite monolith includes the steps of mixing a zeolite dispersion in an aqueous colloidal silica binder with a dispersion of carbon nano-fibers in water followed by dehydration and curing of the binder is given.
1. A monolith, comprising:
zeolite, thermally conductive material, and a binder, wherein said material has a room temperature thermal conductivity greater than 100 W/m·K.
2. The monolith of claim 1 , wherein said zeolite is in the form of beads, pellets, powders or any mixture of beads, pellets, or powders.
3. The monolith of claim 1 , wherein said material is carbon.
4. The monolith of claim 3 , wherein said carbon has a room temperature thermal conductivity of between 200 and 2,500 W/m·K.
5. The monolith of claim 3 , wherein said carbon comprises carbon nano-fibers.
6. The monolith of claim 3 , wherein said carbon comprises about 2 to about 40 weight percent of said monolith.
7. The monolith of claim 1 , wherein said binder comprises a ceramic binder.
8. The monolith of claim 7 , wherein said ceramic binder is derived from colloidal silica.
9. The monolith of claim 1 , wherein said binder comprises about 5 to about 20 weight percent of said monolith.
10. A method of preparing the monolith of claim 1 , comprising the steps of:
providing a zeolite suspension in a binder or binder precursor in a liquid or solution state;
providing a suspension of a thermally conductive carbon in a liquid miscible in said binder liquid or solution;
mixing said zeolite suspension with said thermally conductive carbon suspension to form a mixture;
filling a mold with said mixture;
removing volatile components from said mixture in said mold; and
heating said mold to form a monolith article.
11. The method of claim 10 , further comprising the step of removing said monolithic article from said mold.
12. The method of claim 10 , further comprising the step of machining said article.
13. The method of claim 12 , wherein said machining comprises cutting or drilling.
14. The method of claim 10 , wherein said binder precursor comprises colloidal silica.
15. The method of claim 10 , wherein said suspension of thermally conductive carbon includes a dispersing agent.
16. An evaporative cooling system, comprising:
a water-containing chamber;
a monolith chamber containing the monolith claim 1 , and
a vapor transport channel connecting said water-containing chamber and said monolith chamber.
17. The evaporative cooling system of claim 16 , further comprising a valve in said channel.