There are some incorrect assumptions being made by those who believe that ethanol accelerates the drying process to any significant extent. A more accurate description of the mechanism is that the alcohol helps to soften the lignin enough to relieve some of the stresses that develop as water leaves the wood and it begins to shrink. Back in the early 20th century, there were several patents granted that involved using alcohol to accelerate the time to market when processing dimension lumber. None of the alcohol treatment methods proved to be commercially competitive with kiln drying. The claims that the patents were based on did not include faster drying. Instead, they were based on a method to stabilize the wood against things like checking, twisting, bowing, winding, and shake. The idea was to deliver stable wood more quickly to the customer regardless of its MC. Once it was stable, then it could air dry at the lumber yard.
Personally, I feel that soaking rough turned bowls in alcohol is a waste of time and money -- not that it does not help to reduce warping and cracking, but that there are much cheaper ways to accomplish the same goal and the small amount of time saved is offset by extra work.
As far as your question is concerned, a pressure vessel would be very expensive. If you already have a vacuum pump then making a vacuum enclosure is fairly simple. You could use the same type materials use for vacuum veneering. However, given the limited benefit of alcohol soaking, I would suggest that doing anything beyond just throwing the wood in a bucket of alcohol would, by comparison, make a WPA project look like serious business.