Reactor for hydrothermal growth of structured materials
Design, fabrication, and usage of a reactor are presented for synthesis of structured materials from a liquid-phase precursor by heating. The structured materials are particles, membranes or films of micro-porous molecular sieve crystals such as zeolite and meso-porous materials. The precursor solution and structured materials in the reactor are uniformly heated by a planar heater with characteristic heat transfer dimension in the range of 3 mm to 10 cm. A planar heater having width and length at least three times of the characteristic heat transfer dimension provides at least one surface of uniform temperature distribution for heating purposes. Heating is conducted over a temperature range of 20 to 300° C. The planar heater can be heated by electrical power of by thermal fluid.
1. A method of making a porous structured material comprising:
providing a hydrothermal growth reactor comprising:
a reactor vessel for containment of a precursor and a structured material, the reactor vessel comprising at least two planar heaters configured with even spacing having an aperture in the range of 3 mm to 10 cm and for uniform heating at a controllable rate of the precursor and the structured material, wherein a width and a length of the planar heater is at least three times the spacing; and
at least one removable cover configured to transport the structured material into and out of the reactor vessel;
providing a growth solution comprising the precursor to the aperture; and
synthesizing the porous structured material by heating the growth solution in the hydrothermal growth reactor, wherein the hydrothermal growth reactor is at a temperature less than 300° C.
2. The method of claim 1 , further comprising maintaining a temperature difference of a plurality of growth zones in the hydrothermal growth reactor, wherein the temperature difference between each of the plurality of growth zones is less than 20° C.
3. The method of claim 1 , further comprising heating the growth solution at a heating rate less than 2° C./min.
4. The method of claim 3 , further comprising heating the growth solution at a heating rate less than 1° C./min.
5. The method of claim 1 , wherein providing a growth solution comprises providing an aqueous growth solution containing Al compounds and Si compounds capable of being converted into a micro-porous zeolite material when heated.
6. The method of claim 1 , further comprising heating the hydrothermal growth reactor in a temperature range of 20-300° C. and a pressure range of 1-30 bar.
7. The method of claim 1 , the reactor vessel is heated by providing heated oil to flow channels located in the reactor vessel.
8. The method of claim 7 , wherein the heated oil is providing via a manifold.
9. The method of claim 1 , further comprising maintaining a uniform temperature distribution over surface of the planar heat as measured by a standard deviation of less than 20° C.
10. The method of claim 9 , wherein the standard deviation is less than 10° C.