Well, I wouldn't use "gel" desiccant.

http://www.ppe.com/16pdf/0124.pdf

That's the stuff I use in my dryers, but the key is to circulate air through the bed of desiccant instead of just in it's general vicinity. A professional system will use 2 or 3 beds and cycle the air stream among them, regenerating the beds which are not actively drying and thus enabling endless drying capacity - at least until the desiccant breaks down over time.

A dual bed system looks like this:
ZEKS Heatless Desiccant Flow Diagram Flat.jpg

The problem is that these systems are prohibitively expensive for the home user. You can spend several thousand dollars on a small drying unit. My suspicion is that even a high speed 3dprinter will never need more than about a kg/hr throughput, while the industrial ones are typically built for a minimum 4-5 kg/hr.