Methods and systems for adsorbing organometallic vapor
Described are methods, devices, and systems useful for adsorbing organometallic vapor onto solid adsorbent material to remove the organometallic vapor from a gas mixture that contains the organometallic vapor and other vapor, particulate materials, or both.
1. A method of removing gaseous organometallic vapor from a gas mixture comprising the organometallic vapor and a non-organometallic vapor, the method comprising:
passing the gas mixture through a first particle filter to substantially remove first particles of a first size;
after passing the gas mixture through the first particle filter, passing the gas mixture through a solid adsorbent;
adsorbing the organometallic vapor onto the solid adsorbent; and
after adsorbing the organometallic vapor onto the solid adsorbent, passing the gas mixture through a second particle filter to substantially remove second particles of a second size less than the first size.
2. The method of claim 1 , wherein the gas mixture passes through the solid adsorbent at ambient flow pressure and at a temperature in a range from 0 to 50 degrees Celsius.
3. The method of claim 1 , wherein the non-organometallic vapor comprises one or more of gaseous ammonia, gaseous hydrogen, gaseous nitrogen, and a combination thereof.
4. The method of claim 1 , wherein the organometallic vapor comprises an organometallic compound including gallium.
5. The method of claim 4 , wherein the organometallic vapor is trimethylgallium.
6. The method of claim 1 , wherein the solid adsorbent is selected from a carbon adsorbent, a zeolite, silica, and alumina.
7. The method of claim 1 , wherein the solid adsorbent has a surface area in a range from 100 to 1500 square meters per gram.
8. The method of claim 1 , wherein the solid adsorbent has an average pore size in a range from 3 to 8 angstroms.
9. A method of filtering a gas mixture comprising organometallic vapor, particles, and non-organometallic vapor, the method comprising:
reducing a temperature of the gas mixture by passing the gas mixture through a heat exchanger to produce a cooled gas mixture;
passing the cooled gas mixture through a first particle filter to substantially remove first particles of a first size; and
passing the cooled gas mixture with substantially removed first particles of the first size through a solid adsorbent to adsorb organometallic vapor onto the solid adsorbent; and
after passing the cooled gas mixture with substantially removed first particles of the first size through the solid adsorbent, passing the cooled gas mixture with substantially removed first particles of the first size through a second particle filter to substantially remove second particles of a second size less than the first size.
10. The method of claim 9 , wherein the non-organometallic vapor is selected from gaseous ammonia, gaseous hydrogen, gaseous nitrogen, and a combination thereof.
11. The method of claim 9 , wherein the gas mixture has a temperature greater than 50 degrees Celsius.
12. The method of claim 11 , the temperature of the gas mixture is reduced to a temperature in a range from 0 to 40 degrees Celsius.
13. The method of claim 9 , wherein the step of reducing the temperature of the gas mixture comprises passing the heated gas mixture through a heat exchanger that includes a cooling element having a cooling liquid flowing through the cooling element, the cooling liquid having an inlet temperature of below 30 degrees Celsius.
14. The method of claim 13 , wherein the heat exchanger is a counterflow coil heat exchanger comprising:
a heat exchanger body comprising a body inlet, a body outlet, and a body interior volume, and
a hollow coil body located within the heat exchanger body interior volume and comprising a coil inlet, a coil outlet, and multiple coil turns between the coil inlet and the coil outlet, wherein:
the gas mixture enters the heat exchanger body at the body inlet, flows through the interior volume and over an exterior surface of the hollow coil, and exits the heat exchanger body at the body outlet, and
a cooling liquid enters the hollow coil body at the coil inlet, flows through the hollow coil body in a direction opposite of a direction of flow of the gas mixture passing through the heat exchanger body, and exits the hollow coil body at the coil outlet.
15. The method of claim 9 further comprising vibrating the heat exchanger to prevent organometallic material from collecting on interior surfaces of the heat exchanger.
16. The method of claim 9 , wherein the gas mixture comprises:
from 15 to 40 volume percent gaseous ammonium,
from 0 to 60 volume percent gaseous hydrogen,
from 0 to 70 volume percent gaseous nitrogen, and
organometallic vapor.
17. The method of claim 16 , wherein the organometallic compound is trimethyl gallium.
18. The method of claim 9 , wherein the non-organometallic vapor comprises ammonia, the method further comprising:
after removing the first particles of the first size and the second particles of the second size from the cooled gas mixture and after removing organometallic vapor from the cooled gas mixture, recovering ammonia from the cooled gas mixture.